kgdb in git-x86#mm review

kgdb in git-x86#mm review

[Andi Kleen]

I sent Jan & Jason earlier a quick review of the kgdb code currently in git-x86#mm.

The kgdb code in git-x86#mm is right now is totally broken of course because the CFI
annotations in assembler code are gone now, but they are needed for gdb use. 
And the bogus fault handling code is still in there, but Jason apprently fixed that one.

Here are the other commments I wrote just in case someone is interested.
Overall I would say there is quite a lot of stuff to clean up still.

<snip>

ok, doing a review on the code in git-x86#mm. I have not read
everything in detail, just a quick skip over.

My personal test for clean kernel debugger integration is if the
debugger could be made a loadable (but not unloadable) module with
minor/no effort. How far away is your code from that?

The 32bit in_exception_stack code looks weird. Are you sure you cannot
just use the pt_regs passed to the die notifier?

It might be safer to explicitely disable interrupts early in the notifier.

You should probably use simple_strtoul() instead of inventing an
own hex parser in kgdb.c. And sprintf instead of an own hex writer.
In general more use sprintf would probably shorten a lot of the parser
code.

The num_online_cpu()s check in getthread() looks weird. What is that
supposed to do?

kgdb_softlock_notify: I think the right way to handle this is just
calling touch_softlockup_watchdog() (or perhaps better touch_nmi_watchdog)
Actually it should be only needed once when you exit the debugger
for soft lockup, but regularly for nmi watchdog.

On x86 it is ok, but on other architectures i'm suspect the SMP
synchronization with atomics might benefit from more memory barriers.

gdb_cmd_reboot: always calling emergency_sync looks dangerous.
In fact i suspect if you hold the other CPUs the changes are good
it will lock up. You should at least offer a option to not call that
(or better don't do it by default). Even machine_start is likely
lock up actually if the other CPUs are truly halted (as they should
be) because it will try to halt them. So if anything I suspect you
need to exit the debugger first before executing this.

The logic to halt all the other CPUs in kgdb_handle_exception et.al.
looks a little fragile. It would be probably best to use the same
as kcrash uses factored out into a common function.
One obvious problem is that it is racy against cpu hotplug, but there
are likely others too. With a better implementation you likely
wouldn't need the mdelay(2) hack further down.

You should use raw spinlocks everywhere in the debugger -- i don't
think you want lockdep etc. anywhere.

The unregister hook stuff looks racy against NMIs etc.

-Andi

Re: kgdb in git-x86#mm review

[Frank Ch. Eigler]

Andi Kleen <andi@firstfloor.org> writes:

> [...]  The kgdb code in git-x86#mm is right now is totally broken of
> course because the CFI annotations in assembler code are gone now,
> but they are needed for gdb use.  [...]

This loss of CFI data is unfortunate for other potential consumers
too, such as systemtap, which intends to supplement its current stack
backtracing heuristics with CFI data.

- FChE

Re: kgdb in git-x86#mm review

[Andi Kleen]

On Mon, Feb 11, 2008 at 10:32:46AM -0500, Frank Ch. Eigler wrote:
> Andi Kleen <andi@firstfloor.org> writes:
> 
> > [...]  The kgdb code in git-x86#mm is right now is totally broken of
> > course because the CFI annotations in assembler code are gone now,
> > but they are needed for gdb use.  [...]
> 
> This loss of CFI data is unfortunate for other potential consumers
> too, such as systemtap, which intends to supplement its current stack
> backtracing heuristics with CFI data.

They seem to have reverted these patches now, so that problem 
is gone.

Yes there are a couple of other consumers of CFI too, like crash
or the out of tree (but not dead) in kernel unwinder.

-Andi

[git pull] kgdb-light -v8, (was: Re: kgdb in git-x86#mm review)

[Ingo Molnar]

* Frank Ch. Eigler <fche@redhat.com> wrote:

> Andi Kleen <andi@firstfloor.org> writes:
> 
> > [...]  The kgdb code in git-x86#mm is right now is totally broken of
> > course because the CFI annotations in assembler code are gone now,
> > but they are needed for gdb use.  [...]
> 
> This loss of CFI data is unfortunate for other potential consumers 
> too, such as systemtap, which intends to supplement its current stack 
> backtracing heuristics with CFI data.

yes, but we removed those patches meanwhile because Roland McGrath has 
agreed to clean up the CFI mess. (Thanks Roland! We were very close to 
nuking them altogether because the unreadability they introduced was 
causing real bugs.)

[ btw., Andi's characterisation of it being "totally broken" is 
  incorrect and alarmist. It only means that the "backtrace" command 
  will not work in kgdb in certain types of contexts (only the current 
  function is displayed, not the parent function(s)), but there's no 
  "breakage", just less information available to the debugger. ]

in any case, while there are still holes in the frame annotations and it 
all needs a good bit of cleanup, that is a largely separate issue from 
whether kgdb is merge-worthy or not.

I'd like to thank Andi for his kgdb review efforts and comments. 
Unfortunately they were not done against kgdb-light which is being 
offered for upstream merge, but against an older version of kgdb. (Sorry 
about the 12 hour delay in my reply - Andi's mail did not have any of 
the kgdb or x86 persons Cc:-ed so it was not immediately noticed on a 
busy Monday, only in the lower-prio lkml scans.)

after a quick glance i'm happy to conclude that all but one of Andi's 
review comments were already addressed in kgdb-light -v7 AFAICS, and the 
only one not addressed (emergency_resync()) is now addressed in -v8.

the -v8 kgdb-light tree (against v2.6.25-rc1) can be pulled from:

   git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-kgdb.git

shortlog, diffstat and patch attached below. Tip of the -v8 tree is 
commit f20d70a6dd5785c9dd4c8215daf21f34365ce1c7.

In any case, if there are any open issues we are very much ready and 
willing to address them now or after any potential upstream merge of 
this codebase. This has meanwhile become one of the best-reviewed pieces 
of kernel code in living memory ;-)

	Ingo

------------------>
Ingo Molnar (3):
      pids: add pid_max prototype
      uaccess: add probe_kernel_write()
      x86: kgdb support

Jason Wessel (3):
      kgdb: core
      consoles: polling support, kgdboc
      kgdb: document parameters

 Documentation/kernel-parameters.txt |    5 +
 arch/x86/Kconfig                    |    2 +
 arch/x86/kernel/Makefile            |    1 +
 arch/x86/kernel/kgdb.c              |  654 +++++++++++++
 drivers/char/tty_io.c               |   47 +
 drivers/serial/8250.c               |   58 ++
 drivers/serial/Kconfig              |    3 +
 drivers/serial/Makefile             |    1 +
 drivers/serial/kgdboc.c             |  163 ++++
 drivers/serial/serial_core.c        |   70 ++-
 include/asm-x86/kgdb.h              |   81 ++
 include/linux/kgdb.h                |  314 ++++++
 include/linux/pid.h                 |    2 +
 include/linux/serial_core.h         |    4 +
 include/linux/tty_driver.h          |   12 +
 include/linux/uaccess.h             |   22 +
 kernel/Makefile                     |    1 +
 kernel/kgdb.c                       | 1837 +++++++++++++++++++++++++++++++++++
 kernel/sysctl.c                     |    2 +-
 lib/Kconfig.debug                   |    2 +
 lib/Kconfig.kgdb                    |   40 +
 mm/Makefile                         |    2 +-
 mm/maccess.c                        |   49 +
 23 files changed, 3367 insertions(+), 5 deletions(-)
 create mode 100644 arch/x86/kernel/kgdb.c
 create mode 100644 drivers/serial/kgdboc.c
 create mode 100644 include/asm-x86/kgdb.h
 create mode 100644 include/linux/kgdb.h
 create mode 100644 kernel/kgdb.c
 create mode 100644 lib/Kconfig.kgdb
 create mode 100644 mm/maccess.c

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index a4fc7fc..6e97307 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -930,6 +930,11 @@ and is between 256 and 4096 characters. It is defined in the file
 	kstack=N	[X86-32,X86-64] Print N words from the kernel stack
 			in oops dumps.
 
+	kgdboc=		[HW] kgdb over consoles.
+			Requires a tty driver that supports console polling.
+			(only serial suported for now)
+			Format: <serial_device>[,baud]
+
 	l2cr=		[PPC]
 
 	lapic		[X86-32,APIC] Enable the local APIC even if BIOS
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index aaed1a3..5e0fab5 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -14,6 +14,7 @@ config X86_32
 
 config X86_64
 	def_bool 64BIT
+	select HAVE_ARCH_KGDB_SHADOW_INFO
 
 ### Arch settings
 config X86
@@ -21,6 +22,7 @@ config X86
 	select HAVE_IDE
 	select HAVE_OPROFILE
 	select HAVE_KPROBES
+	select HAVE_ARCH_KGDB
 
 config GENERIC_LOCKBREAK
 	def_bool n
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 76ec0f8..4cd39cd 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -58,6 +58,7 @@ obj-$(CONFIG_MODULES)		+= module_$(BITS).o
 obj-$(CONFIG_ACPI_SRAT) 	+= srat_32.o
 obj-$(CONFIG_EFI) 		+= efi.o efi_$(BITS).o efi_stub_$(BITS).o
 obj-$(CONFIG_DOUBLEFAULT) 	+= doublefault_32.o
+obj-$(CONFIG_KGDB)		+= kgdb.o
 obj-$(CONFIG_VM86)		+= vm86_32.o
 obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
 
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
new file mode 100644
index 0000000..51002f8
--- /dev/null
+++ b/arch/x86/kernel/kgdb.c
@@ -0,0 +1,654 @@
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ */
+
+/*
+ * Copyright (C) 2004 Amit S. Kale <amitkale@linsyssoft.com>
+ * Copyright (C) 2000-2001 VERITAS Software Corporation.
+ * Copyright (C) 2002 Andi Kleen, SuSE Labs
+ * Copyright (C) 2004 LinSysSoft Technologies Pvt. Ltd.
+ * Copyright (C) 2007 MontaVista Software, Inc.
+ * Copyright (C) 2007-2008 Jason Wessel, Wind River Systems, Inc.
+ */
+/****************************************************************************
+ *  Contributor:     Lake Stevens Instrument Division$
+ *  Written by:      Glenn Engel $
+ *  Updated by:	     Amit Kale<akale@veritas.com>
+ *  Updated by:	     Tom Rini <trini@kernel.crashing.org>
+ *  Updated by:	     Jason Wessel <jason.wessel@windriver.com>
+ *  Modified for 386 by Jim Kingdon, Cygnus Support.
+ *  Origianl kgdb, compatibility with 2.1.xx kernel by
+ *  David Grothe <dave@gcom.com>
+ *  Integrated into 2.2.5 kernel by Tigran Aivazian <tigran@sco.com>
+ *  X86_64 changes from Andi Kleen's patch merged by Jim Houston
+ */
+#include <linux/spinlock.h>
+#include <linux/kdebug.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/ptrace.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/kgdb.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+
+#include <asm/apicdef.h>
+#include <asm/system.h>
+
+#ifdef CONFIG_X86_32
+# include <mach_ipi.h>
+#else
+# include <asm/mach_apic.h>
+#endif
+
+/*
+ * Put the error code here just in case the user cares:
+ */
+static int gdb_x86errcode;
+
+/*
+ * Likewise, the vector number here (since GDB only gets the signal
+ * number through the usual means, and that's not very specific):
+ */
+static int gdb_x86vector = -1;
+
+/**
+ *	pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs
+ *	@gdb_regs: A pointer to hold the registers in the order GDB wants.
+ *	@regs: The &struct pt_regs of the current process.
+ *
+ *	Convert the pt_regs in @regs into the format for registers that
+ *	GDB expects, stored in @gdb_regs.
+ */
+void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+	gdb_regs[GDB_AX]	= regs->ax;
+	gdb_regs[GDB_BX]	= regs->bx;
+	gdb_regs[GDB_CX]	= regs->cx;
+	gdb_regs[GDB_DX]	= regs->dx;
+	gdb_regs[GDB_SI]	= regs->si;
+	gdb_regs[GDB_DI]	= regs->di;
+	gdb_regs[GDB_BP]	= regs->bp;
+	gdb_regs[GDB_PS]	= regs->flags;
+	gdb_regs[GDB_PC]	= regs->ip;
+#ifdef CONFIG_X86_32
+	gdb_regs[GDB_DS]	= regs->ds;
+	gdb_regs[GDB_ES]	= regs->es;
+	gdb_regs[GDB_CS]	= regs->cs;
+	gdb_regs[GDB_SS]	= __KERNEL_DS;
+	gdb_regs[GDB_FS]	= 0xFFFF;
+	gdb_regs[GDB_GS]	= 0xFFFF;
+#else
+	gdb_regs[GDB_R8]	= regs->r8;
+	gdb_regs[GDB_R9]	= regs->r9;
+	gdb_regs[GDB_R10]	= regs->r10;
+	gdb_regs[GDB_R11]	= regs->r11;
+	gdb_regs[GDB_R12]	= regs->r12;
+	gdb_regs[GDB_R13]	= regs->r13;
+	gdb_regs[GDB_R14]	= regs->r14;
+	gdb_regs[GDB_R15]	= regs->r15;
+#endif
+	gdb_regs[GDB_SP]	= regs->sp;
+}
+
+/**
+ *	sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs
+ *	@gdb_regs: A pointer to hold the registers in the order GDB wants.
+ *	@p: The &struct task_struct of the desired process.
+ *
+ *	Convert the register values of the sleeping process in @p to
+ *	the format that GDB expects.
+ *	This function is called when kgdb does not have access to the
+ *	&struct pt_regs and therefore it should fill the gdb registers
+ *	@gdb_regs with what has	been saved in &struct thread_struct
+ *	thread field during switch_to.
+ */
+void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
+{
+	gdb_regs[GDB_AX]	= 0;
+	gdb_regs[GDB_BX]	= 0;
+	gdb_regs[GDB_CX]	= 0;
+	gdb_regs[GDB_DX]	= 0;
+	gdb_regs[GDB_SI]	= 0;
+	gdb_regs[GDB_DI]	= 0;
+	gdb_regs[GDB_BP]	= *(unsigned long *)p->thread.sp;
+#ifdef CONFIG_X86_32
+	gdb_regs[GDB_DS]	= __KERNEL_DS;
+	gdb_regs[GDB_ES]	= __KERNEL_DS;
+	gdb_regs[GDB_PS]	= 0;
+	gdb_regs[GDB_CS]	= __KERNEL_CS;
+	gdb_regs[GDB_PC]	= p->thread.ip;
+	gdb_regs[GDB_SS]	= __KERNEL_DS;
+	gdb_regs[GDB_FS]	= 0xFFFF;
+	gdb_regs[GDB_GS]	= 0xFFFF;
+#else
+	gdb_regs[GDB_PS]	= *(unsigned long *)(p->thread.sp + 8);
+	gdb_regs[GDB_PC]	= 0;
+	gdb_regs[GDB_R8]	= 0;
+	gdb_regs[GDB_R9]	= 0;
+	gdb_regs[GDB_R10]	= 0;
+	gdb_regs[GDB_R11]	= 0;
+	gdb_regs[GDB_R12]	= 0;
+	gdb_regs[GDB_R13]	= 0;
+	gdb_regs[GDB_R14]	= 0;
+	gdb_regs[GDB_R15]	= 0;
+#endif
+	gdb_regs[GDB_SP]	= p->thread.sp;
+}
+
+/**
+ *	gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs.
+ *	@gdb_regs: A pointer to hold the registers we've received from GDB.
+ *	@regs: A pointer to a &struct pt_regs to hold these values in.
+ *
+ *	Convert the GDB regs in @gdb_regs into the pt_regs, and store them
+ *	in @regs.
+ */
+void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+	regs->ax		= gdb_regs[GDB_AX];
+	regs->bx		= gdb_regs[GDB_BX];
+	regs->cx		= gdb_regs[GDB_CX];
+	regs->dx		= gdb_regs[GDB_DX];
+	regs->si		= gdb_regs[GDB_SI];
+	regs->di		= gdb_regs[GDB_DI];
+	regs->bp		= gdb_regs[GDB_BP];
+	regs->flags		= gdb_regs[GDB_PS];
+	regs->ip		= gdb_regs[GDB_PC];
+#ifdef CONFIG_X86_32
+	regs->ds		= gdb_regs[GDB_DS];
+	regs->es		= gdb_regs[GDB_ES];
+	regs->cs		= gdb_regs[GDB_CS];
+#else
+	regs->r8		= gdb_regs[GDB_R8];
+	regs->r9		= gdb_regs[GDB_R9];
+	regs->r10		= gdb_regs[GDB_R10];
+	regs->r11		= gdb_regs[GDB_R11];
+	regs->r12		= gdb_regs[GDB_R12];
+	regs->r13		= gdb_regs[GDB_R13];
+	regs->r14		= gdb_regs[GDB_R14];
+	regs->r15		= gdb_regs[GDB_R15];
+#endif
+}
+
+static struct hw_breakpoint {
+	unsigned		enabled;
+	unsigned		type;
+	unsigned		len;
+	unsigned long		addr;
+} breakinfo[4];
+
+static void kgdb_correct_hw_break(void)
+{
+	unsigned long dr7;
+	int correctit = 0;
+	int breakbit;
+	int breakno;
+
+	get_debugreg(dr7, 7);
+	for (breakno = 0; breakno < 4; breakno++) {
+		breakbit = 2 << (breakno << 1);
+		if (!(dr7 & breakbit) && breakinfo[breakno].enabled) {
+			correctit = 1;
+			dr7 |= breakbit;
+			dr7 &= ~(0xf0000 << (breakno << 2));
+			dr7 |= ((breakinfo[breakno].len << 2) |
+				 breakinfo[breakno].type) <<
+			       ((breakno << 2) + 16);
+			if (breakno >= 0 && breakno <= 3)
+				set_debugreg(breakinfo[breakno].addr, breakno);
+
+		} else {
+			if ((dr7 & breakbit) && !breakinfo[breakno].enabled) {
+				correctit = 1;
+				dr7 &= ~breakbit;
+				dr7 &= ~(0xf0000 << (breakno << 2));
+			}
+		}
+	}
+	if (correctit)
+		set_debugreg(dr7, 7);
+}
+
+static int
+kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
+{
+	int i;
+
+	for (i = 0; i < 4; i++)
+		if (breakinfo[i].addr == addr && breakinfo[i].enabled)
+			break;
+	if (i == 4)
+		return -1;
+
+	breakinfo[i].enabled = 0;
+
+	return 0;
+}
+
+static void kgdb_remove_all_hw_break(void)
+{
+	int i;
+
+	for (i = 0; i < 4; i++)
+		memset(&breakinfo[i], 0, sizeof(struct hw_breakpoint));
+}
+
+static int
+kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
+{
+	unsigned type;
+	int i;
+
+	for (i = 0; i < 4; i++)
+		if (!breakinfo[i].enabled)
+			break;
+	if (i == 4)
+		return -1;
+
+	switch (bptype) {
+	case BP_HARDWARE_BREAKPOINT:
+		type = 0;
+		len  = 1;
+		break;
+	case BP_WRITE_WATCHPOINT:
+		type = 1;
+		break;
+	case BP_ACCESS_WATCHPOINT:
+		type = 3;
+		break;
+	default:
+		return -1;
+	}
+
+	if (len == 1 || len == 2 || len == 4)
+		breakinfo[i].len  = len - 1;
+	else
+		return -1;
+
+	breakinfo[i].enabled = 1;
+	breakinfo[i].addr = addr;
+	breakinfo[i].type = type;
+
+	return 0;
+}
+
+/**
+ *	kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
+ *	@regs: Current &struct pt_regs.
+ *
+ *	This function will be called if the particular architecture must
+ *	disable hardware debugging while it is processing gdb packets or
+ *	handling exception.
+ */
+void kgdb_disable_hw_debug(struct pt_regs *regs)
+{
+	/* Disable hardware debugging while we are in kgdb: */
+	set_debugreg(0UL, 7);
+}
+
+/**
+ *	kgdb_post_master_code - Save error vector/code numbers.
+ *	@regs: Original pt_regs.
+ *	@e_vector: Original error vector.
+ *	@err_code: Original error code.
+ *
+ *	This is needed on architectures which support SMP and KGDB.
+ *	This function is called after all the slave cpus have been put
+ *	to a know spin state and the master CPU has control over KGDB.
+ */
+void kgdb_post_master_code(struct pt_regs *regs, int e_vector, int err_code)
+{
+	/* Master processor is completely in the debugger */
+	gdb_x86vector = e_vector;
+	gdb_x86errcode = err_code;
+}
+
+#ifdef CONFIG_SMP
+/**
+ *	kgdb_roundup_cpus - Get other CPUs into a holding pattern
+ *	@flags: Current IRQ state
+ *
+ *	On SMP systems, we need to get the attention of the other CPUs
+ *	and get them be in a known state.  This should do what is needed
+ *	to get the other CPUs to call kgdb_wait(). Note that on some arches,
+ *	the NMI approach is not used for rounding up all the CPUs. For example,
+ *	in case of MIPS, smp_call_function() is used to roundup CPUs. In
+ *	this case, we have to make sure that interrupts are enabled before
+ *	calling smp_call_function(). The argument to this function is
+ *	the flags that will be used when restoring the interrupts. There is
+ *	local_irq_save() call before kgdb_roundup_cpus().
+ *
+ *	On non-SMP systems, this is not called.
+ */
+void kgdb_roundup_cpus(unsigned long flags)
+{
+	send_IPI_allbutself(APIC_DM_NMI);
+}
+#endif
+
+/**
+ *	kgdb_arch_handle_exception - Handle architecture specific GDB packets.
+ *	@vector: The error vector of the exception that happened.
+ *	@signo: The signal number of the exception that happened.
+ *	@err_code: The error code of the exception that happened.
+ *	@remcom_in_buffer: The buffer of the packet we have read.
+ *	@remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
+ *	@regs: The &struct pt_regs of the current process.
+ *
+ *	This function MUST handle the 'c' and 's' command packets,
+ *	as well packets to set / remove a hardware breakpoint, if used.
+ *	If there are additional packets which the hardware needs to handle,
+ *	they are handled here.  The code should return -1 if it wants to
+ *	process more packets, and a %0 or %1 if it wants to exit from the
+ *	kgdb callback.
+ */
+int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
+			       char *remcomInBuffer, char *remcomOutBuffer,
+			       struct pt_regs *linux_regs)
+{
+	unsigned long addr;
+	unsigned long dr6;
+	char *ptr;
+	int newPC;
+
+	switch (remcomInBuffer[0]) {
+	case 'c':
+	case 's':
+		/* try to read optional parameter, pc unchanged if no parm */
+		ptr = &remcomInBuffer[1];
+		if (kgdb_hex2long(&ptr, &addr))
+			linux_regs->ip = addr;
+		newPC = linux_regs->ip;
+
+		/* clear the trace bit */
+		linux_regs->flags &= ~TF_MASK;
+		atomic_set(&kgdb_cpu_doing_single_step, -1);
+
+		/* set the trace bit if we're stepping */
+		if (remcomInBuffer[0] == 's') {
+			linux_regs->flags |= TF_MASK;
+			kgdb_single_step = 1;
+			if (kgdb_contthread) {
+				atomic_set(&kgdb_cpu_doing_single_step,
+					   raw_smp_processor_id());
+			}
+		}
+
+		get_debugreg(dr6, 6);
+		if (!(dr6 & 0x4000)) {
+			int breakno;
+
+			for (breakno = 0; breakno < 4; breakno++) {
+				if (dr6 & (1 << breakno) &&
+				    breakinfo[breakno].type == 0) {
+					/* Set restore flag: */
+					linux_regs->flags |= X86_EFLAGS_RF;
+					break;
+				}
+			}
+		}
+		set_debugreg(0UL, 6);
+		kgdb_correct_hw_break();
+
+		return 0;
+	}
+
+	/* this means that we do not want to exit from the handler: */
+	return -1;
+}
+
+#ifdef CONFIG_X86_64
+
+static struct pt_regs *in_interrupt_stack(unsigned long rsp, int cpu)
+{
+	struct pt_regs *regs = NULL;
+	unsigned long end = (unsigned long)cpu_pda(cpu)->irqstackptr;
+
+	if (rsp <= end && rsp >= end - IRQSTACKSIZE + 8)
+		regs = *(((struct pt_regs **)end) - 1);
+
+	return regs;
+}
+
+static struct pt_regs *in_exception_stack(unsigned long rsp, int cpu)
+{
+	struct tss_struct *init_tss = &__get_cpu_var(init_tss);
+	struct pt_regs *regs;
+	int i;
+
+	for (i = 0; i < N_EXCEPTION_STACKS; i++)
+		if (rsp >= init_tss[cpu].x86_tss.ist[i] &&
+		    rsp <= init_tss[cpu].x86_tss.ist[i] + EXCEPTION_STKSZ) {
+			regs = (void *) init_tss[cpu].x86_tss.ist[i] +\
+				EXCEPTION_STKSZ;
+			return regs - 1;
+		}
+
+	return NULL;
+}
+
+/**
+ *	kgdb_shadowinfo - Get shadowed information on @threadid.
+ *	@regs: The &struct pt_regs of the current process.
+ *	@buffer: A buffer of %BUFMAX size.
+ *	@threadid: The thread id of the shadowed process to get information on.
+ */
+void kgdb_shadowinfo(struct pt_regs *regs, char *buffer, unsigned threadid)
+{
+	static char intr_desc[] = "Stack at interrupt entrypoint";
+	static char exc_desc[] = "Stack at exception entrypoint";
+	int cpu = raw_smp_processor_id();
+	struct pt_regs *stregs;
+
+	stregs = in_interrupt_stack(regs->sp, cpu);
+	if (stregs) {
+		kgdb_mem2hex(intr_desc, buffer, strlen(intr_desc));
+	} else {
+		stregs = in_exception_stack(regs->sp, cpu);
+		if (stregs)
+			kgdb_mem2hex(exc_desc, buffer, strlen(exc_desc));
+	}
+}
+
+/**
+ *	kgdb_get_shadow_thread - Get the shadowed &task_struct of @threadid.
+ *	@regs: The &struct pt_regs of the current thread.
+ *	@threadid: The thread id of the shadowed process to get information on.
+ *
+ *	RETURN:
+ *	This returns a pointer to the &struct task_struct of the shadowed
+ *	thread, @threadid.
+ */
+struct task_struct *kgdb_get_shadow_thread(struct pt_regs *regs, int threadid)
+{
+	int cpu = raw_smp_processor_id();
+	struct pt_regs *stregs;
+
+	stregs = in_interrupt_stack(regs->sp, cpu);
+	if (stregs) {
+		return current;
+	} else {
+		stregs = in_exception_stack(regs->sp, cpu);
+		if (stregs)
+			return current;
+	}
+
+	return NULL;
+}
+
+/**
+ *	kgdb_shadow_regs - Return the shadowed registers of @threadid.
+ *	@regs: The &struct pt_regs of the current thread.
+ *	@threadid: The thread id we want the &struct pt_regs for.
+ *
+ *	RETURN:
+ *	The a pointer to the &struct pt_regs of the shadowed thread @threadid.
+ */
+struct pt_regs *kgdb_shadow_regs(struct pt_regs *regs, int threadid)
+{
+	int cpu = raw_smp_processor_id();
+	struct pt_regs *stregs;
+
+	stregs = in_interrupt_stack(regs->sp, cpu);
+	if (stregs) {
+		return stregs;
+	} else {
+		stregs = in_exception_stack(regs->sp, cpu);
+		if (stregs)
+			return stregs;
+	}
+
+	return NULL;
+}
+
+#endif /* CONFIG_X86_64 */
+
+static inline int
+single_step_cont(struct pt_regs *regs, struct die_args *args)
+{
+	/*
+	 * Single step exception from kernel space to user space so
+	 * eat the exception and continue the process:
+	 */
+	printk(KERN_ERR "KGDB: trap/step from kernel to user space, "
+			"resuming...\n");
+	kgdb_arch_handle_exception(args->trapnr, args->signr,
+				   args->err, "c", "", regs);
+
+	return NOTIFY_STOP;
+}
+
+static int
+kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
+{
+	struct die_args *args = ptr;
+	struct pt_regs *regs = args->regs;
+
+	switch (cmd) {
+	case DIE_NMI:
+		if (atomic_read(&kgdb_active)) {
+			/* KGDB CPU roundup */
+			kgdb_nmicallback(raw_smp_processor_id(), regs);
+			return NOTIFY_STOP;
+		}
+		return NOTIFY_DONE;
+
+	case DIE_NMI_IPI:
+		if (atomic_read(&kgdb_active)) {
+			/* KGDB CPU roundup: */
+			if (kgdb_nmicallback(raw_smp_processor_id(), regs))
+				return NOTIFY_DONE;
+			return NOTIFY_STOP;
+		}
+		return NOTIFY_DONE;
+
+	case DIE_NMIWATCHDOG:
+		if (atomic_read(&kgdb_active)) {
+			/* KGDB CPU roundup: */
+			kgdb_nmicallback(raw_smp_processor_id(), regs);
+			return NOTIFY_STOP;
+		}
+		/* Enter debugger: */
+		break;
+
+	case DIE_DEBUG:
+		if (atomic_read(&kgdb_cpu_doing_single_step) ==
+			raw_smp_processor_id() &&
+			user_mode(regs))
+			return single_step_cont(regs, args);
+		/* fall through */
+	default:
+		if (user_mode(regs))
+			return NOTIFY_DONE;
+	}
+
+	if (kgdb_handle_exception(args->trapnr, args->signr, args->err, regs))
+		return NOTIFY_DONE;
+
+	return NOTIFY_STOP;
+}
+
+static struct notifier_block kgdb_notifier = {
+	.notifier_call	= kgdb_notify,
+
+	/*
+	 * Lowest-prio notifier priority, we want to be notified last:
+	 */
+	.priority	= -INT_MAX,
+};
+
+/**
+ *	kgdb_arch_init - Perform any architecture specific initalization.
+ *
+ *	This function will handle the initalization of any architecture
+ *	specific callbacks.
+ */
+int kgdb_arch_init(void)
+{
+	return register_die_notifier(&kgdb_notifier);
+}
+
+
+/**
+ *	kgdb_arch_uninit - Perform any architecture specific uninitalization.
+ *
+ *	This function will handle the uninitalization of any architecture
+ *	specific callbacks, for dynamic registration and unregistration.
+ */
+void kgdb_arch_uninit(void)
+{
+	unregister_die_notifier(&kgdb_notifier);
+}
+
+/**
+ *
+ *	kgdb_skipexception - Bail of of KGDB when we've been triggered.
+ *	@exception: Exception vector number
+ *	@regs: Current &struct pt_regs.
+ *
+ *	On some architectures we need to skip a breakpoint exception when
+ *	it occurs after a breakpoint has been removed.
+ *
+ * Skip an int3 exception when it occurs after a breakpoint has been
+ * removed. Backtrack eip by 1 since the int3 would have caused it to
+ * increment by 1.
+ */
+int kgdb_skipexception(int exception, struct pt_regs *regs)
+{
+	if (exception == 3 && kgdb_isremovedbreak(regs->ip - 1)) {
+		regs->ip -= 1;
+		return 1;
+	}
+	return 0;
+}
+
+unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs)
+{
+	if (exception == 3)
+		return instruction_pointer(regs) - 1;
+	return instruction_pointer(regs);
+}
+
+struct kgdb_arch arch_kgdb_ops = {
+	/* Breakpoint instruction: */
+	.gdb_bpt_instr		= { 0xcc },
+	.flags			= KGDB_HW_BREAKPOINT,
+#ifndef CONFIG_X86_32
+	.shadowth		= 1,
+#endif
+	.set_hw_breakpoint	= kgdb_set_hw_break,
+	.remove_hw_breakpoint	= kgdb_remove_hw_break,
+	.remove_all_hw_break	= kgdb_remove_all_hw_break,
+	.correct_hw_break	= kgdb_correct_hw_break,
+};
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 613ec81..4d3c701 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -1155,6 +1155,48 @@ static struct tty_driver *get_tty_driver(dev_t device, int *index)
 	return NULL;
 }
 
+#ifdef CONFIG_CONSOLE_POLL
+
+/**
+ *	tty_find_polling_driver	-	find device of a polled tty
+ *	@name: name string to match
+ *	@line: pointer to resulting tty line nr
+ *
+ *	This routine returns a tty driver structure, given a name
+ *	and the condition that the tty driver is capable of polled
+ *	operation.
+ */
+struct tty_driver *tty_find_polling_driver(char *name, int *line)
+{
+	struct tty_driver *p, *res = NULL;
+	int tty_line = 0;
+	char *str;
+
+	mutex_lock(&tty_mutex);
+	/* Search through the tty devices to look for a match */
+	list_for_each_entry(p, &tty_drivers, tty_drivers) {
+		str = name + strlen(p->name);
+		tty_line = simple_strtoul(str, &str, 10);
+		if (*str == ',')
+			str++;
+		if (*str == '\0')
+			str = 0;
+
+		if (tty_line >= 0 && tty_line <= p->num && p->poll_init &&
+				!p->poll_init(p, tty_line, str)) {
+
+			res = p;
+			*line = tty_line;
+			break;
+		}
+	}
+	mutex_unlock(&tty_mutex);
+
+	return res;
+}
+EXPORT_SYMBOL_GPL(tty_find_polling_driver);
+#endif
+
 /**
  *	tty_check_change	-	check for POSIX terminal changes
  *	@tty: tty to check
@@ -3850,6 +3892,11 @@ void tty_set_operations(struct tty_driver *driver,
 	driver->write_proc = op->write_proc;
 	driver->tiocmget = op->tiocmget;
 	driver->tiocmset = op->tiocmset;
+#ifdef CONFIG_CONSOLE_POLL
+	driver->poll_init = op->poll_init;
+	driver->poll_get_char = op->poll_get_char;
+	driver->poll_put_char = op->poll_put_char;
+#endif
 }
 
 
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 77f7a7f..96a585e 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -1740,6 +1740,60 @@ static inline void wait_for_xmitr(struct uart_8250_port *up, int bits)
 	}
 }
 
+#ifdef CONFIG_CONSOLE_POLL
+/*
+ * Console polling routines for writing and reading from the uart while
+ * in an interrupt or debug context.
+ */
+
+static int serial8250_get_poll_char(struct uart_port *port)
+{
+	struct uart_8250_port *up = (struct uart_8250_port *)port;
+	unsigned char lsr = serial_inp(up, UART_LSR);
+
+	while (!(lsr & UART_LSR_DR))
+		lsr = serial_inp(up, UART_LSR);
+
+	return serial_inp(up, UART_RX);
+}
+
+
+static void serial8250_put_poll_char(struct uart_port *port,
+			 unsigned char c)
+{
+	unsigned int ier;
+	struct uart_8250_port *up = (struct uart_8250_port *)port;
+
+	/*
+	 *	First save the IER then disable the interrupts
+	 */
+	ier = serial_in(up, UART_IER);
+	if (up->capabilities & UART_CAP_UUE)
+		serial_out(up, UART_IER, UART_IER_UUE);
+	else
+		serial_out(up, UART_IER, 0);
+
+	wait_for_xmitr(up, BOTH_EMPTY);
+	/*
+	 *	Send the character out.
+	 *	If a LF, also do CR...
+	 */
+	serial_out(up, UART_TX, c);
+	if (c == 10) {
+		wait_for_xmitr(up, BOTH_EMPTY);
+		serial_out(up, UART_TX, 13);
+	}
+
+	/*
+	 *	Finally, wait for transmitter to become empty
+	 *	and restore the IER
+	 */
+	wait_for_xmitr(up, BOTH_EMPTY);
+	serial_out(up, UART_IER, ier);
+}
+
+#endif /* CONFIG_CONSOLE_POLL */
+
 static int serial8250_startup(struct uart_port *port)
 {
 	struct uart_8250_port *up = (struct uart_8250_port *)port;
@@ -2386,6 +2440,10 @@ static struct uart_ops serial8250_pops = {
 	.request_port	= serial8250_request_port,
 	.config_port	= serial8250_config_port,
 	.verify_port	= serial8250_verify_port,
+#ifdef CONFIG_CONSOLE_POLL
+	.poll_get_char = serial8250_get_poll_char,
+	.poll_put_char = serial8250_put_poll_char,
+#endif
 };
 
 static struct uart_8250_port serial8250_ports[UART_NR];
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index b82595c..5d9667c 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -961,6 +961,9 @@ config SERIAL_CORE
 config SERIAL_CORE_CONSOLE
 	bool
 
+config CONSOLE_POLL
+	bool
+
 config SERIAL_68328
 	bool "68328 serial support"
 	depends on M68328 || M68EZ328 || M68VZ328
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 640cfe4..3cbea54 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -66,4 +66,5 @@ obj-$(CONFIG_SERIAL_UARTLITE) += uartlite.o
 obj-$(CONFIG_SERIAL_NETX) += netx-serial.o
 obj-$(CONFIG_SERIAL_OF_PLATFORM) += of_serial.o
 obj-$(CONFIG_SERIAL_KS8695) += serial_ks8695.o
+obj-$(CONFIG_KGDB_SERIAL_CONSOLE) += kgdboc.o
 obj-$(CONFIG_SERIAL_QE) += ucc_uart.o
diff --git a/drivers/serial/kgdboc.c b/drivers/serial/kgdboc.c
new file mode 100644
index 0000000..3418307
--- /dev/null
+++ b/drivers/serial/kgdboc.c
@@ -0,0 +1,163 @@
+/*
+ * Based on the same principle as kgdboe using the NETPOLL api, this
+ * driver uses a console polling api to implement a gdb serial inteface
+ * which is multiplexed on a console port.
+ *
+ * Maintainer: Jason Wessel <jason.wessel@windriver.com>
+ *
+ * 2007-2008 (c) Jason Wessel - Wind River Systems, Inc.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+#include <linux/kernel.h>
+#include <linux/ctype.h>
+#include <linux/kgdb.h>
+#include <linux/tty.h>
+
+#define MAX_CONFIG_LEN		40
+
+static struct kgdb_io		kgdboc_io_ops;
+
+/* -1 = init not run yet, 0 = unconfigured, 1 = configured. */
+static int configured		= -1;
+
+static char config[MAX_CONFIG_LEN];
+static struct kparam_string kps = {
+	.string			= config,
+	.maxlen			= MAX_CONFIG_LEN,
+};
+
+static struct tty_driver	*kgdb_tty_driver;
+static int			kgdb_tty_line;
+
+static int kgdboc_option_setup(char *opt)
+{
+	if (strlen(opt) > MAX_CONFIG_LEN) {
+		printk(KERN_ERR "kgdboc: config string too long\n");
+		return -ENOSPC;
+	}
+	strcpy(config, opt);
+
+	return 0;
+}
+
+__setup("kgdboc=", kgdboc_option_setup);
+
+static int configure_kgdboc(void)
+{
+	struct tty_driver *p;
+	int tty_line = 0;
+	int err;
+
+	err = kgdboc_option_setup(config);
+	if (err || !strlen(config) || isspace(config[0]))
+		goto noconfig;
+
+	err = -ENODEV;
+
+	p = tty_find_polling_driver(config, &tty_line);
+	if (!p)
+		goto noconfig;
+
+	kgdb_tty_driver = p;
+	kgdb_tty_line = tty_line;
+
+	err = kgdb_register_io_module(&kgdboc_io_ops);
+	if (err)
+		goto noconfig;
+
+	configured = 1;
+
+	return 0;
+
+noconfig:
+	config[0] = 0;
+	configured = 0;
+
+	return err;
+}
+
+static int __init init_kgdboc(void)
+{
+	/* Already configured? */
+	if (configured == 1)
+		return 0;
+
+	return configure_kgdboc();
+}
+
+static void cleanup_kgdboc(void)
+{
+	if (configured == 1)
+		kgdb_unregister_io_module(&kgdboc_io_ops);
+}
+
+static int kgdboc_get_char(void)
+{
+	return kgdb_tty_driver->poll_get_char(kgdb_tty_driver, kgdb_tty_line);
+}
+
+static void kgdboc_put_char(u8 chr)
+{
+	kgdb_tty_driver->poll_put_char(kgdb_tty_driver, kgdb_tty_line, chr);
+}
+
+static int param_set_kgdboc_var(const char *kmessage, struct kernel_param *kp)
+{
+	if (strlen(kmessage) >= MAX_CONFIG_LEN) {
+		printk(KERN_ERR "kgdboc: config string too long\n");
+		return -ENOSPC;
+	}
+
+	/* Only copy in the string if the init function has not run yet */
+	if (configured < 0) {
+		strcpy(config, kmessage);
+		return 0;
+	}
+
+	if (kgdb_connected) {
+		printk(KERN_ERR
+		       "kgdboc: Cannot reconfigure while KGDB is connected.\n");
+
+		return -EBUSY;
+	}
+
+	strcpy(config, kmessage);
+
+	if (configured == 1)
+		cleanup_kgdboc();
+
+	/* Go and configure with the new params. */
+	return configure_kgdboc();
+}
+
+static void kgdboc_pre_exp_handler(void)
+{
+	/* Increment the module count when the debugger is active */
+	if (!kgdb_connected)
+		try_module_get(THIS_MODULE);
+}
+
+static void kgdboc_post_exp_handler(void)
+{
+	/* decrement the module count when the debugger detaches */
+	if (!kgdb_connected)
+		module_put(THIS_MODULE);
+}
+
+static struct kgdb_io kgdboc_io_ops = {
+	.name			= "kgdboc",
+	.read_char		= kgdboc_get_char,
+	.write_char		= kgdboc_put_char,
+	.pre_exception		= kgdboc_pre_exp_handler,
+	.post_exception		= kgdboc_post_exp_handler,
+};
+
+module_init(init_kgdboc);
+module_exit(cleanup_kgdboc);
+module_param_call(kgdboc, param_set_kgdboc_var, param_get_string, &kps, 0644);
+MODULE_PARM_DESC(kgdboc, "<serial_device>[,baud]");
+MODULE_DESCRIPTION("KGDB Console TTY Driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index 0f5a179..cec193b 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -1827,7 +1827,7 @@ uart_get_console(struct uart_port *ports, int nr, struct console *co)
  *	options.  The format of the string is <baud><parity><bits><flow>,
  *	eg: 115200n8r
  */
-void __init
+void
 uart_parse_options(char *options, int *baud, int *parity, int *bits, int *flow)
 {
 	char *s = options;
@@ -1872,7 +1872,7 @@ static const struct baud_rates baud_rates[] = {
  *	@bits: number of data bits
  *	@flow: flow control character - 'r' (rts)
  */
-int __init
+int
 uart_set_options(struct uart_port *port, struct console *co,
 		 int baud, int parity, int bits, int flow)
 {
@@ -1924,7 +1924,12 @@ uart_set_options(struct uart_port *port, struct console *co,
 	port->mctrl |= TIOCM_DTR;
 
 	port->ops->set_termios(port, &termios, &dummy);
-	co->cflag = termios.c_cflag;
+	/*
+	 * Allow the setting of the UART parameters with a NULL console
+	 * too:
+	 */
+	if (co)
+		co->cflag = termios.c_cflag;
 
 	return 0;
 }
@@ -2182,6 +2187,60 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state,
 	}
 }
 
+#ifdef CONFIG_CONSOLE_POLL
+
+static int uart_poll_init(struct tty_driver *driver, int line, char *options)
+{
+	struct uart_driver *drv = driver->driver_state;
+	struct uart_state *state = drv->state + line;
+	struct uart_port *port;
+	int baud = 9600;
+	int bits = 8;
+	int parity = 'n';
+	int flow = 'n';
+
+	if (!state || !state->port)
+		return -1;
+
+	port = state->port;
+	if (!(port->ops->poll_get_char && port->ops->poll_put_char))
+		return -1;
+
+	if (options) {
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+		return uart_set_options(port, NULL, baud, parity, bits, flow);
+	}
+
+	return 0;
+}
+
+static int uart_poll_get_char(struct tty_driver *driver, int line)
+{
+	struct uart_driver *drv = driver->driver_state;
+	struct uart_state *state = drv->state + line;
+	struct uart_port *port;
+
+	if (!state || !state->port)
+		return -1;
+
+	port = state->port;
+	return port->ops->poll_get_char(port);
+}
+
+static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
+{
+	struct uart_driver *drv = driver->driver_state;
+	struct uart_state *state = drv->state + line;
+	struct uart_port *port;
+
+	if (!state || !state->port)
+		return;
+
+	port = state->port;
+	port->ops->poll_put_char(port, ch);
+}
+#endif
+
 static const struct tty_operations uart_ops = {
 	.open		= uart_open,
 	.close		= uart_close,
@@ -2206,6 +2265,11 @@ static const struct tty_operations uart_ops = {
 #endif
 	.tiocmget	= uart_tiocmget,
 	.tiocmset	= uart_tiocmset,
+#ifdef CONFIG_CONSOLE_POLL
+	.poll_init	= uart_poll_init,
+	.poll_get_char	= uart_poll_get_char,
+	.poll_put_char	= uart_poll_put_char,
+#endif
 };
 
 /**
diff --git a/include/asm-x86/kgdb.h b/include/asm-x86/kgdb.h
new file mode 100644
index 0000000..484c475
--- /dev/null
+++ b/include/asm-x86/kgdb.h
@@ -0,0 +1,81 @@
+#ifndef _ASM_KGDB_H_
+#define _ASM_KGDB_H_
+
+/*
+ * Copyright (C) 2001-2004 Amit S. Kale
+ * Copyright (C) 2008 Wind River Systems, Inc.
+ */
+
+/*
+ * BUFMAX defines the maximum number of characters in inbound/outbound
+ * buffers at least NUMREGBYTES*2 are needed for register packets
+ * Longer buffer is needed to list all threads
+ */
+#define BUFMAX			1024
+
+/*
+ *  Note that this register image is in a different order than
+ *  the register image that Linux produces at interrupt time.
+ *
+ *  Linux's register image is defined by struct pt_regs in ptrace.h.
+ *  Just why GDB uses a different order is a historical mystery.
+ */
+#ifdef CONFIG_X86_32
+enum regnames {
+	GDB_AX,			/* 0 */
+	GDB_CX,			/* 1 */
+	GDB_DX,			/* 2 */
+	GDB_BX,			/* 3 */
+	GDB_SP,			/* 4 */
+	GDB_BP,			/* 5 */
+	GDB_SI,			/* 6 */
+	GDB_DI,			/* 7 */
+	GDB_PC,			/* 8 also known as eip */
+	GDB_PS,			/* 9 also known as eflags */
+	GDB_CS,			/* 10 */
+	GDB_SS,			/* 11 */
+	GDB_DS,			/* 12 */
+	GDB_ES,			/* 13 */
+	GDB_FS,			/* 14 */
+	GDB_GS,			/* 15 */
+};
+#else /* ! CONFIG_X86_32 */
+enum regnames {
+	GDB_AX,			/* 0 */
+	GDB_DX,			/* 1 */
+	GDB_CX,			/* 2 */
+	GDB_BX,			/* 3 */
+	GDB_SI,			/* 4 */
+	GDB_DI,			/* 5 */
+	GDB_BP,			/* 6 */
+	GDB_SP,			/* 7 */
+	GDB_R8,			/* 8 */
+	GDB_R9,			/* 9 */
+	GDB_R10,		/* 10 */
+	GDB_R11,		/* 11 */
+	GDB_R12,		/* 12 */
+	GDB_R13,		/* 13 */
+	GDB_R14,		/* 14 */
+	GDB_R15,		/* 15 */
+	GDB_PC,			/* 16 */
+	GDB_PS,			/* 17 */
+};
+#endif /* CONFIG_X86_32 */
+
+/*
+ * Number of bytes of registers:
+ */
+#ifdef CONFIG_X86_32
+# define NUMREGBYTES		64
+#else
+# define NUMREGBYTES		((GDB_PS+1)*8)
+#endif
+
+static inline void arch_kgdb_breakpoint(void)
+{
+	asm("   int $3");
+}
+#define BREAK_INSTR_SIZE	1
+#define CACHE_FLUSH_IS_SAFE	1
+
+#endif				/* _ASM_KGDB_H_ */
diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h
new file mode 100644
index 0000000..67a40b9
--- /dev/null
+++ b/include/linux/kgdb.h
@@ -0,0 +1,314 @@
+/*
+ * This provides the callbacks and functions that KGDB needs to share between
+ * the core, I/O and arch-specific portions.
+ *
+ * Author: Amit Kale <amitkale@linsyssoft.com> and
+ *         Tom Rini <trini@kernel.crashing.org>
+ *
+ * 2001-2004 (c) Amit S. Kale and 2003-2005 (c) MontaVista Software, Inc.
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2. This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+#ifndef _KGDB_H_
+#define _KGDB_H_
+
+#include <linux/serial_8250.h>
+#include <linux/linkage.h>
+#include <linux/init.h>
+
+#include <asm/atomic.h>
+#include <asm/kgdb.h>
+
+struct pt_regs;
+
+/*
+ *	kgdb_skipexception - Bail of of KGDB when we've been triggered.
+ *	@exception: Exception vector number
+ *	@regs: Current &struct pt_regs.
+ *
+ *	On some architectures we need to skip a breakpoint exception when
+ *	it occurs after a breakpoint has been removed.
+ */
+extern int kgdb_skipexception(int exception, struct pt_regs *regs);
+
+/*
+ *	kgdb_post_master_code - Save error vector/code numbers.
+ *	@regs: Original pt_regs.
+ *	@e_vector: Original error vector.
+ *	@err_code: Original error code.
+ *
+ *	This is needed on architectures which support SMP and KGDB.
+ *	This function is called after all the slave cpus have been put
+ *	to a know spin state and the master CPU has control over KGDB.
+ */
+extern void kgdb_post_master_code(struct pt_regs *regs, int e_vector,
+				  int err_code);
+
+/*
+ *	kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
+ *	@regs: Current &struct pt_regs.
+ *
+ *	This function will be called if the particular architecture must
+ *	disable hardware debugging while it is processing gdb packets or
+ *	handling exception.
+ */
+extern void kgdb_disable_hw_debug(struct pt_regs *regs);
+
+#ifdef CONFIG_HAVE_ARCH_KGDB_SHADOW_INFO
+/*
+ *	kgdb_shadowinfo - Get shadowed information on @threadid.
+ *	@regs: The &struct pt_regs of the current process.
+ *	@buffer: A buffer of %BUFMAX size.
+ *	@threadid: The thread id of the shadowed process to get information on.
+ */
+extern void kgdb_shadowinfo(struct pt_regs *regs, char *buffer,
+			    unsigned threadid);
+
+/*
+ *	kgdb_get_shadow_thread - Get the shadowed &task_struct of @threadid.
+ *	@regs: The &struct pt_regs of the current thread.
+ *	@threadid: The thread id of the shadowed process to get information on.
+ *
+ *	RETURN:
+ *	This returns a pointer to the &struct task_struct of the shadowed
+ *	thread, @threadid.
+ */
+extern struct task_struct *kgdb_get_shadow_thread(struct pt_regs *regs,
+						  int threadid);
+
+/*
+ *	kgdb_shadow_regs - Return the shadowed registers of @threadid.
+ *	@regs: The &struct pt_regs of the current thread.
+ *	@threadid: The thread id we want the &struct pt_regs for.
+ *
+ *	RETURN:
+ *	The a pointer to the &struct pt_regs of the shadowed thread @threadid.
+ */
+extern struct pt_regs *kgdb_shadow_regs(struct pt_regs *regs, int threadid);
+#else
+#define kgdb_shadowinfo(regs, buf, threadid)		do { } while (0)
+#define kgdb_get_shadow_thread(regs, threadid)		NULL
+#define kgdb_shadow_regs(regs, threadid)		NULL
+#endif
+
+struct tasklet_struct;
+struct task_struct;
+struct uart_port;
+
+/* To enter the debugger explicitly. */
+void kgdb_breakpoint(void);
+
+extern int kgdb_connected;
+
+extern atomic_t			kgdb_setting_breakpoint;
+extern atomic_t			kgdb_cpu_doing_single_step;
+
+extern struct task_struct	*kgdb_usethread;
+extern struct task_struct	*kgdb_contthread;
+
+enum kgdb_bptype {
+	BP_BREAKPOINT = 0,
+	BP_HARDWARE_BREAKPOINT,
+	BP_WRITE_WATCHPOINT,
+	BP_READ_WATCHPOINT,
+	BP_ACCESS_WATCHPOINT
+};
+
+enum kgdb_bpstate {
+	BP_UNDEFINED = 0,
+	BP_REMOVED,
+	BP_SET,
+	BP_ACTIVE
+};
+
+struct kgdb_bkpt {
+	unsigned long		bpt_addr;
+	unsigned char		saved_instr[BREAK_INSTR_SIZE];
+	enum kgdb_bptype	type;
+	enum kgdb_bpstate	state;
+};
+
+#ifndef KGDB_MAX_BREAKPOINTS
+# define KGDB_MAX_BREAKPOINTS	1000
+#endif
+
+#define KGDB_HW_BREAKPOINT	1
+
+/*
+ * Functions each KGDB-supporting architecture must provide:
+ */
+
+/*
+ *	kgdb_arch_init - Perform any architecture specific initalization.
+ *
+ *	This function will handle the initalization of any architecture
+ *	specific callbacks.
+ */
+extern int kgdb_arch_init(void);
+
+/*
+ *	kgdb_arch_uninit - Perform any architecture specific uninitalization.
+ *
+ *	This function will handle the uninitalization of any architecture
+ *	specific callbacks, for dynamic registration and unregistration.
+ */
+extern void kgdb_arch_uninit(void);
+
+/*
+ *	pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs
+ *	@gdb_regs: A pointer to hold the registers in the order GDB wants.
+ *	@regs: The &struct pt_regs of the current process.
+ *
+ *	Convert the pt_regs in @regs into the format for registers that
+ *	GDB expects, stored in @gdb_regs.
+ */
+extern void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs);
+
+/*
+ *	sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs
+ *	@gdb_regs: A pointer to hold the registers in the order GDB wants.
+ *	@p: The &struct task_struct of the desired process.
+ *
+ *	Convert the register values of the sleeping process in @p to
+ *	the format that GDB expects.
+ *	This function is called when kgdb does not have access to the
+ *	&struct pt_regs and therefore it should fill the gdb registers
+ *	@gdb_regs with what has	been saved in &struct thread_struct
+ *	thread field during switch_to.
+ */
+extern void
+sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p);
+
+/*
+ *	gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs.
+ *	@gdb_regs: A pointer to hold the registers we've received from GDB.
+ *	@regs: A pointer to a &struct pt_regs to hold these values in.
+ *
+ *	Convert the GDB regs in @gdb_regs into the pt_regs, and store them
+ *	in @regs.
+ */
+extern void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs);
+
+/*
+ *	kgdb_arch_handle_exception - Handle architecture specific GDB packets.
+ *	@vector: The error vector of the exception that happened.
+ *	@signo: The signal number of the exception that happened.
+ *	@err_code: The error code of the exception that happened.
+ *	@remcom_in_buffer: The buffer of the packet we have read.
+ *	@remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
+ *	@regs: The &struct pt_regs of the current process.
+ *
+ *	This function MUST handle the 'c' and 's' command packets,
+ *	as well packets to set / remove a hardware breakpoint, if used.
+ *	If there are additional packets which the hardware needs to handle,
+ *	they are handled here.  The code should return -1 if it wants to
+ *	process more packets, and a %0 or %1 if it wants to exit from the
+ *	kgdb callback.
+ */
+extern int
+kgdb_arch_handle_exception(int vector, int signo, int err_code,
+			   char *remcom_in_buffer,
+			   char *remcom_out_buffer,
+			   struct pt_regs *regs);
+
+/*
+ *	kgdb_roundup_cpus - Get other CPUs into a holding pattern
+ *	@flags: Current IRQ state
+ *
+ *	On SMP systems, we need to get the attention of the other CPUs
+ *	and get them be in a known state.  This should do what is needed
+ *	to get the other CPUs to call kgdb_wait(). Note that on some arches,
+ *	the NMI approach is not used for rounding up all the CPUs. For example,
+ *	in case of MIPS, smp_call_function() is used to roundup CPUs. In
+ *	this case, we have to make sure that interrupts are enabled before
+ *	calling smp_call_function(). The argument to this function is
+ *	the flags that will be used when restoring the interrupts. There is
+ *	local_irq_save() call before kgdb_roundup_cpus().
+ *
+ *	On non-SMP systems, this is not called.
+ */
+extern void kgdb_roundup_cpus(unsigned long flags);
+
+/* Optional functions. */
+extern int kgdb_validate_break_address(unsigned long addr);
+extern int kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr);
+extern int kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle);
+
+/*
+ * struct kgdb_arch - Describe architecture specific values.
+ * @gdb_bpt_instr: The instruction to trigger a breakpoint.
+ * @flags: Flags for the breakpoint, currently just %KGDB_HW_BREAKPOINT.
+ * @shadowth: A value of %1 indicates we shadow information on processes.
+ * @set_breakpoint: Allow an architecture to specify how to set a software
+ * breakpoint.
+ * @remove_breakpoint: Allow an architecture to specify how to remove a
+ * software breakpoint.
+ * @set_hw_breakpoint: Allow an architecture to specify how to set a hardware
+ * breakpoint.
+ * @remove_hw_breakpoint: Allow an architecture to specify how to remove a
+ * hardware breakpoint.
+ * @remove_all_hw_break: Allow an architecture to specify how to remove all
+ * hardware breakpoints.
+ * @correct_hw_break: Allow an architecture to specify how to correct the
+ * hardware debug registers.
+ *
+ * The @shadowth flag is an option to shadow information not retrievable by
+ * gdb otherwise.  This is deprecated in favor of a binutils which supports
+ * CFI macros.
+ */
+struct kgdb_arch {
+	unsigned char		gdb_bpt_instr[BREAK_INSTR_SIZE];
+	unsigned long		flags;
+	unsigned		shadowth;
+
+	int	(*set_breakpoint)(unsigned long, char *);
+	int	(*remove_breakpoint)(unsigned long, char *);
+	int	(*set_hw_breakpoint)(unsigned long, int, enum kgdb_bptype);
+	int	(*remove_hw_breakpoint)(unsigned long, int, enum kgdb_bptype);
+	void	(*remove_all_hw_break)(void);
+	void	(*correct_hw_break)(void);
+};
+
+/*
+ * struct kgdb_io - Describe the interface for an I/O driver to talk with KGDB.
+ * @name: Name of the I/O driver.
+ * @read_char: Pointer to a function that will return one char.
+ * @write_char: Pointer to a function that will write one char.
+ * @flush: Pointer to a function that will flush any pending writes.
+ * @init: Pointer to a function that will initialize the device.
+ * @pre_exception: Pointer to a function that will do any prep work for
+ * the I/O driver.
+ * @post_exception: Pointer to a function that will do any cleanup work
+ * for the I/O driver.
+ */
+struct kgdb_io {
+	const char		*name;
+	int			(*read_char) (void);
+	void			(*write_char) (u8);
+	void			(*flush) (void);
+	int			(*init) (void);
+	void			(*pre_exception) (void);
+	void			(*post_exception) (void);
+};
+
+extern struct kgdb_arch		arch_kgdb_ops;
+
+extern int kgdb_register_io_module(struct kgdb_io *local_kgdb_io_ops);
+extern void kgdb_unregister_io_module(struct kgdb_io *local_kgdb_io_ops);
+
+extern int kgdb_hex2long(char **ptr, long *long_val);
+extern int kgdb_mem2hex(char *mem, char *buf, int count);
+extern int kgdb_hex2mem(char *buf, char *mem, int count);
+
+extern int kgdb_isremovedbreak(unsigned long addr);
+
+extern int
+kgdb_handle_exception(int ex_vector, int signo, int err_code,
+		      struct pt_regs *regs);
+extern int kgdb_nmicallback(int cpu, void *regs);
+
+extern int			kgdb_single_step;
+extern atomic_t			kgdb_active;
+
+#endif /* _KGDB_H_ */
diff --git a/include/linux/pid.h b/include/linux/pid.h
index f84d532..e066d3d 100644
--- a/include/linux/pid.h
+++ b/include/linux/pid.h
@@ -86,6 +86,8 @@ extern struct task_struct *FASTCALL(get_pid_task(struct pid *pid,
 
 extern struct pid *get_task_pid(struct task_struct *task, enum pid_type type);
 
+extern int pid_max;
+
 /*
  * attach_pid() and detach_pid() must be called with the tasklist_lock
  * write-held.
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 1a0b6cf..7d1a46b 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -211,6 +211,10 @@ struct uart_ops {
 	void		(*config_port)(struct uart_port *, int);
 	int		(*verify_port)(struct uart_port *, struct serial_struct *);
 	int		(*ioctl)(struct uart_port *, unsigned int, unsigned long);
+#ifdef CONFIG_CONSOLE_POLL
+	void	(*poll_put_char)(struct uart_port *, unsigned char);
+	int		(*poll_get_char)(struct uart_port *);
+#endif
 };
 
 #define UART_CONFIG_TYPE	(1 << 0)
diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index 85c95cd..21f69ac 100644
--- a/include/linux/tty_driver.h
+++ b/include/linux/tty_driver.h
@@ -125,6 +125,7 @@
 #include <linux/cdev.h>
 
 struct tty_struct;
+struct tty_driver;
 
 struct tty_operations {
 	int  (*open)(struct tty_struct * tty, struct file * filp);
@@ -157,6 +158,11 @@ struct tty_operations {
 	int (*tiocmget)(struct tty_struct *tty, struct file *file);
 	int (*tiocmset)(struct tty_struct *tty, struct file *file,
 			unsigned int set, unsigned int clear);
+#ifdef CONFIG_CONSOLE_POLL
+	int (*poll_init)(struct tty_driver *driver, int line, char *options);
+	int (*poll_get_char)(struct tty_driver *driver, int line);
+	void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
+#endif
 };
 
 struct tty_driver {
@@ -220,6 +226,11 @@ struct tty_driver {
 	int (*tiocmget)(struct tty_struct *tty, struct file *file);
 	int (*tiocmset)(struct tty_struct *tty, struct file *file,
 			unsigned int set, unsigned int clear);
+#ifdef CONFIG_CONSOLE_POLL
+	int (*poll_init)(struct tty_driver *driver, int line, char *options);
+	int (*poll_get_char)(struct tty_driver *driver, int line);
+	void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
+#endif
 
 	struct list_head tty_drivers;
 };
@@ -230,6 +241,7 @@ struct tty_driver *alloc_tty_driver(int lines);
 void put_tty_driver(struct tty_driver *driver);
 void tty_set_operations(struct tty_driver *driver,
 			const struct tty_operations *op);
+extern struct tty_driver *tty_find_polling_driver(char *name, int *line);
 
 /* tty driver magic number */
 #define TTY_DRIVER_MAGIC		0x5402
diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index 975c963..fec6dec 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -84,4 +84,26 @@ static inline unsigned long __copy_from_user_nocache(void *to,
 		ret;					\
 	})
 
+/*
+ * probe_kernel_read(): safely attempt to read from a location
+ * @dst: pointer to the buffer that shall take the data
+ * @src: address to read from
+ * @size: size of the data chunk
+ *
+ * Safely read from address @src to the buffer at @dst.  If a kernel fault
+ * happens, handle that and return -EFAULT.
+ */
+extern long probe_kernel_read(void *dst, void *src, size_t size);
+
+/*
+ * probe_kernel_write(): safely attempt to write to a location
+ * @dst: address to write to
+ * @src: pointer to the data that shall be written
+ * @size: size of the data chunk
+ *
+ * Safely write to address @dst from the buffer at @src.  If a kernel fault
+ * happens, handle that and return -EFAULT.
+ */
+extern long probe_kernel_write(void *dst, void *src, size_t size);
+
 #endif		/* __LINUX_UACCESS_H__ */
diff --git a/kernel/Makefile b/kernel/Makefile
index 6c584c5..05c8003 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -53,6 +53,7 @@ obj-$(CONFIG_AUDIT) += audit.o auditfilter.o
 obj-$(CONFIG_AUDITSYSCALL) += auditsc.o
 obj-$(CONFIG_AUDIT_TREE) += audit_tree.o
 obj-$(CONFIG_KPROBES) += kprobes.o
+obj-$(CONFIG_KGDB) += kgdb.o
 obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
 obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
 obj-$(CONFIG_SECCOMP) += seccomp.o
diff --git a/kernel/kgdb.c b/kernel/kgdb.c
new file mode 100644
index 0000000..58421ee
--- /dev/null
+++ b/kernel/kgdb.c
@@ -0,0 +1,1837 @@
+/*
+ * KGDB stub.
+ *
+ * Maintainer: Jason Wessel <jason.wessel@windriver.com>
+ *
+ * Copyright (C) 2000-2001 VERITAS Software Corporation.
+ * Copyright (C) 2002-2004 Timesys Corporation
+ * Copyright (C) 2003-2004 Amit S. Kale <amitkale@linsyssoft.com>
+ * Copyright (C) 2004 Pavel Machek <pavel@suse.cz>
+ * Copyright (C) 2004-2006 Tom Rini <trini@kernel.crashing.org>
+ * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd.
+ * Copyright (C) 2005-2008 Wind River Systems, Inc.
+ * Copyright (C) 2007 MontaVista Software, Inc.
+ * Copyright (C) 2008 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ * Contributors at various stages not listed above:
+ *  Jason Wessel ( jason.wessel@windriver.com )
+ *  George Anzinger <george@mvista.com>
+ *  Anurekh Saxena (anurekh.saxena@timesys.com)
+ *  Lake Stevens Instrument Division (Glenn Engel)
+ *  Jim Kingdon, Cygnus Support.
+ *
+ * Original KGDB stub: David Grothe <dave@gcom.com>,
+ * Tigran Aivazian <tigran@sco.com>
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2. This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+#include <linux/pid_namespace.h>
+#include <linux/interrupt.h>
+#include <linux/notifier.h>
+#include <linux/spinlock.h>
+#include <linux/console.h>
+#include <linux/threads.h>
+#include <linux/uaccess.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/ptrace.h>
+#include <linux/reboot.h>
+#include <linux/string.h>
+#include <linux/delay.h>
+#include <linux/sched.h>
+#include <linux/sysrq.h>
+#include <linux/init.h>
+#include <linux/kgdb.h>
+#include <linux/pid.h>
+#include <linux/smp.h>
+#include <linux/mm.h>
+
+#include <asm/cacheflush.h>
+#include <asm/byteorder.h>
+#include <asm/atomic.h>
+#include <asm/system.h>
+
+static int kgdb_break_asap;
+
+struct kgdb_state {
+	int			all_cpus_synced;
+	int			ex_vector;
+	int			signo;
+	int			err_code;
+	int			cpu;
+	int			pass_exception;
+	long			threadid;
+	long			kgdb_usethreadid;
+	struct pt_regs		*linux_regs;
+};
+
+static struct debuggerinfo_struct {
+	void			*debuggerinfo;
+	struct task_struct	*task;
+} kgdb_info[NR_CPUS];
+
+/**
+ * kgdb_connected - Is a host GDB connected to us?
+ */
+int				kgdb_connected;
+EXPORT_SYMBOL_GPL(kgdb_connected);
+
+/* All the KGDB handlers are installed */
+static int			kgdb_io_module_registered;
+
+/* Guard for recursive entry */
+static int			exception_level;
+
+static struct kgdb_io		*kgdb_io_ops;
+static DEFINE_SPINLOCK(kgdb_registration_lock);
+
+/*
+ * Holds information about breakpoints in a kernel. These breakpoints are
+ * added and removed by gdb.
+ */
+static struct kgdb_bkpt		kgdb_break[KGDB_MAX_BREAKPOINTS] = {
+	[0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED }
+};
+
+/*
+ * KGDB locking is really nasty at places - but we really can only
+ * do sane debugging if all processors are in a controlled state.
+ *
+ * So we go through painful cycles of wait and see, with every
+ * CPU having a lock:
+ */
+
+/* How many times to count all of the waiting CPUs */
+#define ROUNDUP_WAIT		640000	/* Arbitrary, increase if needed. */
+#define BUF_THREAD_ID_SIZE	16
+
+static spinlock_t		slave_cpu_locks[NR_CPUS] = {
+	[0 ... NR_CPUS-1] = __SPIN_LOCK_UNLOCKED(slave_cpu_locks)
+};
+static atomic_t			cpu_in_kgdb[NR_CPUS];
+atomic_t			kgdb_setting_breakpoint;
+
+struct task_struct		*kgdb_usethread;
+struct task_struct		*kgdb_contthread;
+
+int				kgdb_single_step;
+static atomic_t			kgdb_sync = ATOMIC_INIT(-1);
+atomic_t			kgdb_active;
+
+/* Our I/O buffers. */
+static char			remcom_in_buffer[BUFMAX];
+static char			remcom_out_buffer[BUFMAX];
+
+/* Storage for the registers, in GDB format. */
+static unsigned long		gdb_regs[(NUMREGBYTES +
+					sizeof(unsigned long) - 1) /
+					sizeof(unsigned long)];
+
+/* to keep track of the CPU which is doing the single stepping*/
+atomic_t			kgdb_cpu_doing_single_step = ATOMIC_INIT(-1);
+
+static int
+kgdb_notify_reboot(struct notifier_block *this, unsigned long code, void *x);
+
+/* reboot notifier block */
+static struct notifier_block kgdb_reboot_notifier = {
+	.notifier_call		= kgdb_notify_reboot,
+	.priority		= INT_MAX,
+};
+
+/*
+ * Finally, some KGDB code :-)
+ */
+
+/*
+ * Weak aliases for breakpoint management,
+ * can be overriden by architectures when needed:
+ */
+int __weak kgdb_validate_break_address(unsigned long addr)
+{
+	char tmp_variable[BREAK_INSTR_SIZE];
+
+	return probe_kernel_read((char *)addr, tmp_variable, BREAK_INSTR_SIZE);
+}
+
+int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr)
+{
+	int err;
+
+	err = probe_kernel_read((char *)addr, saved_instr, BREAK_INSTR_SIZE);
+	if (err)
+		return err;
+
+	return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr,
+				  BREAK_INSTR_SIZE);
+}
+
+int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle)
+{
+	return probe_kernel_write((char *)addr,
+				  (char *)bundle, BREAK_INSTR_SIZE);
+}
+
+unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs)
+{
+	return instruction_pointer(regs);
+}
+
+/*
+ * GDB remote protocol parser:
+ */
+
+static const char	hexchars[] = "0123456789abcdef";
+
+static int hex(char ch)
+{
+	if ((ch >= 'a') && (ch <= 'f'))
+		return ch - 'a' + 10;
+	if ((ch >= '0') && (ch <= '9'))
+		return ch - '0';
+	if ((ch >= 'A') && (ch <= 'F'))
+		return ch - 'A' + 10;
+	return -1;
+}
+
+/* scan for the sequence $<data>#<checksum> */
+static void get_packet(char *buffer)
+{
+	unsigned char checksum;
+	unsigned char xmitcsum;
+	int count;
+	char ch;
+
+	do {
+		/*
+		 * Spin and wait around for the start character, ignore all
+		 * other characters:
+		 */
+		while ((ch = (kgdb_io_ops->read_char())) != '$')
+			/* nothing */;
+
+		kgdb_connected = 1;
+		checksum = 0;
+		xmitcsum = -1;
+
+		count = 0;
+
+		/*
+		 * now, read until a # or end of buffer is found:
+		 */
+		while (count < (BUFMAX - 1)) {
+			ch = kgdb_io_ops->read_char();
+			if (ch == '#')
+				break;
+			checksum = checksum + ch;
+			buffer[count] = ch;
+			count = count + 1;
+		}
+		buffer[count] = 0;
+
+		if (ch == '#') {
+			xmitcsum = hex(kgdb_io_ops->read_char()) << 4;
+			xmitcsum += hex(kgdb_io_ops->read_char());
+
+			if (checksum != xmitcsum)
+				/* failed checksum */
+				kgdb_io_ops->write_char('-');
+			else
+				/* successful transfer */
+				kgdb_io_ops->write_char('+');
+			if (kgdb_io_ops->flush)
+				kgdb_io_ops->flush();
+		}
+	} while (checksum != xmitcsum);
+}
+
+/*
+ * Send the packet in buffer.
+ * Check for gdb connection if asked for.
+ */
+static void put_packet(char *buffer)
+{
+	unsigned char checksum;
+	int count;
+	char ch;
+
+	/*
+	 * $<packet info>#<checksum>.
+	 */
+	while (1) {
+		kgdb_io_ops->write_char('$');
+		checksum = 0;
+		count = 0;
+
+		while ((ch = buffer[count])) {
+			kgdb_io_ops->write_char(ch);
+			checksum += ch;
+			count++;
+		}
+
+		kgdb_io_ops->write_char('#');
+		kgdb_io_ops->write_char(hexchars[checksum >> 4]);
+		kgdb_io_ops->write_char(hexchars[checksum & 0xf]);
+		if (kgdb_io_ops->flush)
+			kgdb_io_ops->flush();
+
+		/* Now see what we get in reply. */
+		ch = kgdb_io_ops->read_char();
+
+		if (ch == 3)
+			ch = kgdb_io_ops->read_char();
+
+		/* If we get an ACK, we are done. */
+		if (ch == '+')
+			return;
+
+		/*
+		 * If we get the start of another packet, this means
+		 * that GDB is attempting to reconnect.  We will NAK
+		 * the packet being sent, and stop trying to send this
+		 * packet.
+		 */
+		if (ch == '$') {
+			kgdb_io_ops->write_char('-');
+			if (kgdb_io_ops->flush)
+				kgdb_io_ops->flush();
+			return;
+		}
+	}
+}
+
+static char *pack_hex_byte(char *pkt, u8 byte)
+{
+	*pkt++ = hexchars[byte >> 4];
+	*pkt++ = hexchars[byte & 0xf];
+
+	return pkt;
+}
+
+/*
+ * Convert the memory pointed to by mem into hex, placing result in buf.
+ * Return a pointer to the last char put in buf (null). May return an error.
+ */
+int kgdb_mem2hex(char *mem, char *buf, int count)
+{
+	char *tmp;
+	int err;
+
+	/*
+	 * We use the upper half of buf as an intermediate buffer for the
+	 * raw memory copy.  Hex conversion will work against this one.
+	 */
+	tmp = buf + count;
+
+	err = probe_kernel_read(tmp, mem, count);
+	if (!err) {
+		while (count > 0) {
+			buf = pack_hex_byte(buf, *tmp);
+			tmp++;
+			count--;
+		}
+
+		*buf = 0;
+	}
+
+	return err;
+}
+
+/*
+ * Copy the binary array pointed to by buf into mem.  Fix $, #, and
+ * 0x7d escaped with 0x7d.  Return a pointer to the character after
+ * the last byte written.
+ */
+static int kgdb_ebin2mem(char *buf, char *mem, int count)
+{
+	int err = 0;
+	char c;
+
+	while (count-- > 0) {
+		c = *buf++;
+		if (c == 0x7d)
+			c = *buf++ ^ 0x20;
+
+		err = probe_kernel_write(mem, &c, 1);
+		if (err)
+			break;
+
+		mem++;
+	}
+
+	return err;
+}
+
+/*
+ * Convert the hex array pointed to by buf into binary to be placed in mem.
+ * Return a pointer to the character AFTER the last byte written.
+ * May return an error.
+ */
+int kgdb_hex2mem(char *buf, char *mem, int count)
+{
+	char *tmp_raw;
+	char *tmp_hex;
+
+	/*
+	 * We use the upper half of buf as an intermediate buffer for the
+	 * raw memory that is converted from hex.
+	 */
+	tmp_raw = buf + count * 2;
+
+	tmp_hex = tmp_raw - 1;
+	while (tmp_hex >= buf) {
+		tmp_raw--;
+		*tmp_raw = hex(*tmp_hex--);
+		*tmp_raw |= hex(*tmp_hex--) << 4;
+	}
+
+	return probe_kernel_write(mem, tmp_raw, count);
+}
+
+/*
+ * While we find nice hex chars, build a long_val.
+ * Return number of chars processed.
+ */
+int kgdb_hex2long(char **ptr, long *long_val)
+{
+	int hex_val;
+	int num = 0;
+
+	*long_val = 0;
+
+	while (**ptr) {
+		hex_val = hex(**ptr);
+		if (hex_val < 0)
+			break;
+
+		*long_val = (*long_val << 4) | hex_val;
+		num++;
+		(*ptr)++;
+	}
+
+	return num;
+}
+
+/* Write memory due to an 'M' or 'X' packet. */
+static int write_mem_msg(int binary)
+{
+	char *ptr = &remcom_in_buffer[1];
+	unsigned long addr;
+	unsigned long length;
+	int err;
+
+	if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' &&
+	    kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') {
+		if (binary)
+			err = kgdb_ebin2mem(ptr, (char *)addr, length);
+		else
+			err = kgdb_hex2mem(ptr, (char *)addr, length);
+		if (err)
+			return err;
+		if (CACHE_FLUSH_IS_SAFE)
+			flush_icache_range(addr, addr + length + 1);
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static void error_packet(char *pkt, int error)
+{
+	error = -error;
+	pkt[0] = 'E';
+	pkt[1] = hexchars[(error / 10)];
+	pkt[2] = hexchars[(error % 10)];
+	pkt[3] = '\0';
+}
+
+/*
+ * Black magic portion #2. Thread ID accessors.
+ */
+
+static char *pack_threadid(char *pkt, unsigned char *id)
+{
+	char *limit;
+
+	limit = pkt + BUF_THREAD_ID_SIZE;
+	while (pkt < limit)
+		pkt = pack_hex_byte(pkt, *id++);
+
+	return pkt;
+}
+
+static void int_to_threadref(unsigned char *id, int value)
+{
+	unsigned char *scan;
+	int i = 4;
+
+	scan = (unsigned char *)id;
+	while (i--)
+		*scan++ = 0;
+	*scan++ = (value >> 24) & 0xff;
+	*scan++ = (value >> 16) & 0xff;
+	*scan++ = (value >> 8) & 0xff;
+	*scan++ = (value & 0xff);
+}
+
+static struct task_struct *getthread(struct pt_regs *regs, int tid)
+{
+	if (init_pid_ns.last_pid == 0)
+		return current;
+
+	if (num_online_cpus() && (tid >= pid_max + num_online_cpus() +
+							arch_kgdb_ops.shadowth))
+		return NULL;
+
+	if (arch_kgdb_ops.shadowth && (tid >= pid_max + num_online_cpus())) {
+		return kgdb_get_shadow_thread(regs, tid - pid_max -
+					      num_online_cpus());
+	}
+
+	if (tid >= pid_max)
+		return idle_task(tid - pid_max);
+
+	if (!tid)
+		return NULL;
+
+	/*
+	 * find_task_by_pid() does not take the tasklist lock anymore
+	 * but is nicely RCU locked - hence is a pretty resilient
+	 * thing to use:
+	 */
+	return find_task_by_pid(tid);
+}
+
+/*
+ * CPU debug state control:
+ */
+
+#ifdef CONFIG_SMP
+static void kgdb_wait(struct pt_regs *regs)
+{
+	unsigned long flags;
+	int cpu;
+
+	local_irq_save(flags);
+	cpu = raw_smp_processor_id();
+	kgdb_info[cpu].debuggerinfo = regs;
+	kgdb_info[cpu].task = current;
+	atomic_set(&cpu_in_kgdb[cpu], 1);
+
+	/*
+	 * The master CPU must be active to enter here, but this is
+	 * gaurd in case the master CPU had not been selected if
+	 * this was an entry via nmi.
+	 */
+	while (!atomic_read(&kgdb_active))
+		cpu_relax();
+
+	/* Wait till master CPU goes completely into the debugger. */
+	while (!atomic_read(&cpu_in_kgdb[atomic_read(&kgdb_active) - 1])) {
+		int i = 10;	/* an arbitrary number. Be nice. A bit. */
+
+		while (--i)
+			cpu_relax();
+	}
+
+	/* Wait till master CPU is done with debugging */
+	spin_lock(&slave_cpu_locks[cpu]);
+
+	kgdb_info[cpu].debuggerinfo = NULL;
+	kgdb_info[cpu].task = NULL;
+
+	/* fix up hardware debug registers on local cpu */
+	if (arch_kgdb_ops.correct_hw_break)
+		arch_kgdb_ops.correct_hw_break();
+
+	/* Signal the master CPU that we are done: */
+	atomic_set(&cpu_in_kgdb[cpu], 0);
+	spin_unlock(&slave_cpu_locks[cpu]);
+	local_irq_restore(flags);
+}
+#endif
+
+/*
+ * Some architectures need cache flushes when we set/clear a
+ * breakpoint:
+ */
+static void kgdb_flush_swbreak_addr(unsigned long addr)
+{
+	if (!CACHE_FLUSH_IS_SAFE)
+		return;
+
+	if (current->mm) {
+		flush_cache_range(current->mm->mmap_cache,
+				  addr, addr + BREAK_INSTR_SIZE);
+	} else {
+		flush_icache_range(addr, addr + BREAK_INSTR_SIZE);
+	}
+}
+
+/*
+ * SW breakpoint management:
+ */
+static int kgdb_activate_sw_breakpoints(void)
+{
+	unsigned long addr;
+	int error = 0;
+	int i;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (kgdb_break[i].state != BP_SET)
+			continue;
+
+		addr = kgdb_break[i].bpt_addr;
+		error = kgdb_arch_set_breakpoint(addr,
+				kgdb_break[i].saved_instr);
+		if (error)
+			return error;
+
+		kgdb_flush_swbreak_addr(addr);
+		kgdb_break[i].state = BP_ACTIVE;
+	}
+	return 0;
+}
+
+static int kgdb_set_sw_break(unsigned long addr)
+{
+	int err = kgdb_validate_break_address(addr);
+	int breakno = -1;
+	int i;
+
+	if (err)
+		return err;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if ((kgdb_break[i].state == BP_SET) &&
+					(kgdb_break[i].bpt_addr == addr))
+			return -EEXIST;
+	}
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (kgdb_break[i].state == BP_REMOVED &&
+					kgdb_break[i].bpt_addr == addr) {
+			breakno = i;
+			break;
+		}
+	}
+
+	if (breakno == -1) {
+		for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+			if (kgdb_break[i].state == BP_UNDEFINED) {
+				breakno = i;
+				break;
+			}
+		}
+	}
+
+	if (breakno == -1)
+		return -E2BIG;
+
+	kgdb_break[breakno].state = BP_SET;
+	kgdb_break[breakno].type = BP_BREAKPOINT;
+	kgdb_break[breakno].bpt_addr = addr;
+
+	return 0;
+}
+
+static int kgdb_deactivate_sw_breakpoints(void)
+{
+	unsigned long addr;
+	int error = 0;
+	int i;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (kgdb_break[i].state != BP_ACTIVE)
+			continue;
+		addr = kgdb_break[i].bpt_addr;
+		error = kgdb_arch_remove_breakpoint(addr,
+					kgdb_break[i].saved_instr);
+		if (error)
+			return error;
+
+		kgdb_flush_swbreak_addr(addr);
+		kgdb_break[i].state = BP_SET;
+	}
+	return 0;
+}
+
+static int kgdb_remove_sw_break(unsigned long addr)
+{
+	int i;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if ((kgdb_break[i].state == BP_SET) &&
+				(kgdb_break[i].bpt_addr == addr)) {
+			kgdb_break[i].state = BP_REMOVED;
+			return 0;
+		}
+	}
+	return -ENOENT;
+}
+
+int kgdb_isremovedbreak(unsigned long addr)
+{
+	int i;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if ((kgdb_break[i].state == BP_REMOVED) &&
+					(kgdb_break[i].bpt_addr == addr))
+			return 1;
+	}
+	return 0;
+}
+
+int remove_all_break(void)
+{
+	unsigned long addr;
+	int error;
+	int i;
+
+	/* Clear memory breakpoints. */
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (kgdb_break[i].state != BP_SET)
+			continue;
+		addr = kgdb_break[i].bpt_addr;
+		error = kgdb_arch_remove_breakpoint(addr,
+				kgdb_break[i].saved_instr);
+		if (error)
+			return error;
+		kgdb_break[i].state = BP_REMOVED;
+	}
+
+	/* Clear hardware breakpoints. */
+	if (arch_kgdb_ops.remove_all_hw_break)
+		arch_kgdb_ops.remove_all_hw_break();
+
+	return 0;
+}
+
+static inline int shadow_pid(int realpid)
+{
+	if (realpid)
+		return realpid;
+
+	return pid_max + raw_smp_processor_id();
+}
+
+static char gdbmsgbuf[BUFMAX + 1];
+
+static void kgdb_msg_write(const char *s, int len)
+{
+	char *bufptr;
+	int wcount;
+	int i;
+
+	/* 'O'utput */
+	gdbmsgbuf[0] = 'O';
+
+	/* Fill and send buffers... */
+	while (len > 0) {
+		bufptr = gdbmsgbuf + 1;
+
+		/* Calculate how many this time */
+		if ((len << 1) > (BUFMAX - 2))
+			wcount = (BUFMAX - 2) >> 1;
+		else
+			wcount = len;
+
+		/* Pack in hex chars */
+		for (i = 0; i < wcount; i++)
+			bufptr = pack_hex_byte(bufptr, s[i]);
+		*bufptr = '\0';
+
+		/* Move up */
+		s += wcount;
+		len -= wcount;
+
+		/* Write packet */
+		put_packet(gdbmsgbuf);
+	}
+}
+
+/*
+ * Return true if there is a valid kgdb I/O module.  Also if no
+ * debugger is attached a message can be printed to the console about
+ * waiting for the debugger to attach.
+ *
+ * The print_wait argument is only to be true when called from inside
+ * the core kgdb_handle_exception, because it will wait for the
+ * debugger to attach.
+ */
+static int kgdb_io_ready(int print_wait)
+{
+	if (!kgdb_io_ops)
+		return 0;
+	if (kgdb_connected)
+		return 1;
+	if (atomic_read(&kgdb_setting_breakpoint))
+		return 1;
+	if (print_wait)
+		printk(KERN_CRIT "KGDB: Waiting for remote debugger\n");
+	return 1;
+}
+
+/*
+ * All the functions that start with gdb_cmd are the various
+ * operations to implement the handlers for the gdbserial protocol
+ * where KGDB is communicating with an external debugger
+ */
+
+/* Handle the '?' status packets */
+static void gdb_cmd_status(struct kgdb_state *ks)
+{
+	/*
+	 * We know that this packet is only sent
+	 * during initial connect.  So to be safe,
+	 * we clear out our breakpoints now in case
+	 * GDB is reconnecting.
+	 */
+	remove_all_break();
+
+	/*
+	 * Also, if we haven't been able to roundup all
+	 * CPUs, send an 'O' packet informing the user
+	 * as much.  Only need to do this once.
+	 */
+	if (!ks->all_cpus_synced)
+		kgdb_msg_write("Not all CPUs have been synced for KGDB\n", 39);
+
+	remcom_out_buffer[0] = 'S';
+	pack_hex_byte(&remcom_out_buffer[1], ks->signo);
+}
+
+/* Handle the 'g' get registers request */
+static void gdb_cmd_getregs(struct kgdb_state *ks)
+{
+	struct pt_regs *shadowregs;
+	struct task_struct *thread;
+	void *local_debuggerinfo;
+	int i;
+
+	thread = kgdb_usethread;
+	if (!thread) {
+		thread = kgdb_info[ks->cpu].task;
+		local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo;
+	} else {
+		local_debuggerinfo = NULL;
+		for (i = 0; i < NR_CPUS; i++) {
+			/*
+			 * Try to find the task on some other
+			 * or possibly this node if we do not
+			 * find the matching task then we try
+			 * to approximate the results.
+			 */
+			if (thread == kgdb_info[i].task)
+				local_debuggerinfo = kgdb_info[i].debuggerinfo;
+		}
+	}
+
+	/*
+	 * All threads that don't have debuggerinfo should be
+	 * in __schedule() sleeping, since all other CPUs
+	 * are in kgdb_wait, and thus have debuggerinfo.
+	 */
+	if (arch_kgdb_ops.shadowth &&
+			ks->kgdb_usethreadid >= pid_max + num_online_cpus()) {
+
+		shadowregs = kgdb_shadow_regs(ks->linux_regs,
+					  ks->kgdb_usethreadid -
+					  pid_max -
+					  num_online_cpus());
+		if (!shadowregs) {
+			error_packet(remcom_out_buffer, -EINVAL);
+			return;
+		}
+		pt_regs_to_gdb_regs(gdb_regs, shadowregs);
+	} else {
+		if (local_debuggerinfo) {
+			pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo);
+		} else {
+			/*
+			 * Pull stuff saved during switch_to; nothing
+			 * else is accessible (or even particularly
+			 * relevant).
+			 *
+			 * This should be enough for a stack trace.
+			 */
+			sleeping_thread_to_gdb_regs(gdb_regs, thread);
+		}
+	}
+	kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES);
+}
+
+/* Handle the 'G' set registers request */
+static void gdb_cmd_setregs(struct kgdb_state *ks)
+{
+	kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES);
+
+	if (kgdb_usethread && kgdb_usethread != current) {
+		error_packet(remcom_out_buffer, -EINVAL);
+	} else {
+		gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs);
+		strcpy(remcom_out_buffer, "OK");
+	}
+}
+
+/* Handle the 'm' memory read bytes */
+static void gdb_cmd_memread(struct kgdb_state *ks)
+{
+	char *ptr = &remcom_in_buffer[1];
+	unsigned long length;
+	unsigned long addr;
+	int err;
+
+	if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' &&
+					kgdb_hex2long(&ptr, &length) > 0) {
+		err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length);
+		if (err)
+			error_packet(remcom_out_buffer, err);
+	} else {
+		error_packet(remcom_out_buffer, -EINVAL);
+	}
+}
+
+/* Handle the 'M' memory write bytes */
+static void gdb_cmd_memwrite(struct kgdb_state *ks)
+{
+	int err = write_mem_msg(0);
+
+	if (err)
+		error_packet(remcom_out_buffer, err);
+	else
+		strcpy(remcom_out_buffer, "OK");
+}
+
+/* Handle the 'X' memory binary write bytes */
+static void gdb_cmd_binwrite(struct kgdb_state *ks)
+{
+	int err = write_mem_msg(1);
+
+	if (err)
+		error_packet(remcom_out_buffer, err);
+	else
+		strcpy(remcom_out_buffer, "OK");
+}
+
+/* Handle the 'D' or 'k', detach or kill packets */
+static void gdb_cmd_detachkill(struct kgdb_state *ks)
+{
+	int error;
+
+	/* The detach case */
+	if (remcom_in_buffer[0] == 'D') {
+		error = remove_all_break();
+		if (error < 0) {
+			error_packet(remcom_out_buffer, error);
+		} else {
+			strcpy(remcom_out_buffer, "OK");
+			kgdb_connected = 0;
+		}
+		put_packet(remcom_out_buffer);
+	} else {
+		/*
+		 * Assume the kill case, with no exit code checking,
+		 * trying to force detach the debugger:
+		 */
+		remove_all_break();
+		kgdb_connected = 0;
+	}
+}
+
+/* Handle the 'R' reboot packets */
+static int gdb_cmd_reboot(struct kgdb_state *ks)
+{
+	/* For now, only honor R0 */
+	if (strcmp(remcom_in_buffer, "R0") == 0) {
+		printk(KERN_CRIT "Executing reboot\n");
+		strcpy(remcom_out_buffer, "OK");
+		put_packet(remcom_out_buffer);
+
+		/*
+		 * Execution should not return from
+		 * machine_restart()
+		 */
+		machine_restart(NULL);
+		kgdb_connected = 0;
+
+		return 1;
+	}
+	return 0;
+}
+
+/* Handle the 'q' query packets */
+static void gdb_cmd_query(struct kgdb_state *ks)
+{
+	int numshadowth = num_online_cpus() + arch_kgdb_ops.shadowth;
+	struct task_struct *thread;
+	unsigned char thref[8];
+	char *ptr;
+	int i;
+
+	switch (remcom_in_buffer[1]) {
+	case 's':
+	case 'f':
+		if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) {
+			error_packet(remcom_out_buffer, -EINVAL);
+			break;
+		}
+
+		/*
+		 * If we have not yet completed in
+		 * pidhash_init() there isn't much we
+		 * can give back.
+		 */
+		if (init_pid_ns.last_pid == 0) {
+			if (remcom_in_buffer[1] == 'f')
+				strcpy(remcom_out_buffer, "m0000000000000001");
+			break;
+		}
+
+		if (remcom_in_buffer[1] == 'f')
+			ks->threadid = 1;
+
+		remcom_out_buffer[0] = 'm';
+		ptr = remcom_out_buffer + 1;
+
+		for (i = 0; i < 17 && ks->threadid < pid_max + numshadowth;
+							ks->threadid++) {
+
+			thread = getthread(ks->linux_regs, ks->threadid);
+			if (thread) {
+				int_to_threadref(thref, ks->threadid);
+				pack_threadid(ptr, thref);
+				ptr += 16;
+				*(ptr++) = ',';
+				i++;
+			}
+		}
+		*(--ptr) = '\0';
+		break;
+
+	case 'C':
+		/* Current thread id */
+		strcpy(remcom_out_buffer, "QC");
+		ks->threadid = shadow_pid(current->pid);
+		int_to_threadref(thref, ks->threadid);
+		pack_threadid(remcom_out_buffer + 2, thref);
+		break;
+	case 'T':
+		if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) {
+			error_packet(remcom_out_buffer, -EINVAL);
+			break;
+		}
+		ks->threadid = 0;
+		ptr = remcom_in_buffer + 17;
+		kgdb_hex2long(&ptr, &ks->threadid);
+		if (!getthread(ks->linux_regs, ks->threadid)) {
+			error_packet(remcom_out_buffer, -EINVAL);
+			break;
+		}
+		if (ks->threadid < pid_max) {
+			kgdb_mem2hex(getthread(ks->linux_regs,
+					ks->threadid)->comm,
+					remcom_out_buffer, 16);
+		} else {
+			if (ks->threadid >= pid_max + num_online_cpus()) {
+				kgdb_shadowinfo(ks->linux_regs,
+					remcom_out_buffer,
+					ks->threadid - pid_max -
+					num_online_cpus());
+			} else {
+				static char tmpstr[23 + BUF_THREAD_ID_SIZE];
+				sprintf(tmpstr, "Shadow task %d for pid 0",
+						(int)(ks->threadid - pid_max));
+				kgdb_mem2hex(tmpstr, remcom_out_buffer,
+							 strlen(tmpstr));
+			}
+		}
+		break;
+	}
+}
+
+/* Handle the 'H' task query packets */
+static void gdb_cmd_task(struct kgdb_state *ks)
+{
+	struct task_struct *thread;
+	char *ptr;
+
+	switch (remcom_in_buffer[1]) {
+	case 'g':
+		ptr = &remcom_in_buffer[2];
+		kgdb_hex2long(&ptr, &ks->threadid);
+		thread = getthread(ks->linux_regs, ks->threadid);
+		if (!thread && ks->threadid > 0) {
+			error_packet(remcom_out_buffer, -EINVAL);
+			break;
+		}
+		kgdb_usethread = thread;
+		ks->kgdb_usethreadid = ks->threadid;
+		strcpy(remcom_out_buffer, "OK");
+		break;
+	case 'c':
+		ptr = &remcom_in_buffer[2];
+		kgdb_hex2long(&ptr, &ks->threadid);
+		if (!ks->threadid) {
+			kgdb_contthread = NULL;
+		} else {
+			thread = getthread(ks->linux_regs, ks->threadid);
+			if (!thread && ks->threadid > 0) {
+				error_packet(remcom_out_buffer, -EINVAL);
+				break;
+			}
+			kgdb_contthread = thread;
+		}
+		strcpy(remcom_out_buffer, "OK");
+		break;
+	}
+}
+
+/* Handle the 'T' thread query packets */
+static void gdb_cmd_thread(struct kgdb_state *ks)
+{
+	char *ptr = &remcom_in_buffer[1];
+	struct task_struct *thread;
+
+	kgdb_hex2long(&ptr, &ks->threadid);
+	thread = getthread(ks->linux_regs, ks->threadid);
+	if (thread)
+		strcpy(remcom_out_buffer, "OK");
+	else
+		error_packet(remcom_out_buffer, -EINVAL);
+}
+
+/* Handle the 'z' or 'Z' breakpoint remove or set packets */
+static void gdb_cmd_break(struct kgdb_state *ks)
+{
+	/*
+	 * Since GDB-5.3, it's been drafted that '0' is a software
+	 * breakpoint, '1' is a hardware breakpoint, so let's do that.
+	 */
+	char *bpt_type = &remcom_in_buffer[1];
+	char *ptr = &remcom_in_buffer[2];
+	unsigned long addr;
+	unsigned long length;
+	int error = 0;
+
+	if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') {
+		/* Unsupported */
+		if (*bpt_type > '4')
+			return;
+	} else {
+		if (*bpt_type != '0' && *bpt_type != '1')
+			/* Unsupported. */
+			return;
+	}
+
+	/*
+	 * Test if this is a hardware breakpoint, and
+	 * if we support it:
+	 */
+	if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT))
+		/* Unsupported. */
+		return;
+
+	if (*(ptr++) != ',') {
+		error_packet(remcom_out_buffer, -EINVAL);
+		return;
+	}
+	if (!kgdb_hex2long(&ptr, &addr)) {
+		error_packet(remcom_out_buffer, -EINVAL);
+		return;
+	}
+	if (*(ptr++) != ',' ||
+		!kgdb_hex2long(&ptr, &length)) {
+		error_packet(remcom_out_buffer, -EINVAL);
+		return;
+	}
+
+	if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0')
+		error = kgdb_set_sw_break(addr);
+	else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0')
+		error = kgdb_remove_sw_break(addr);
+	else if (remcom_in_buffer[0] == 'Z')
+		error = arch_kgdb_ops.set_hw_breakpoint(addr,
+			(int)length, *bpt_type);
+	else if (remcom_in_buffer[0] == 'z')
+		error = arch_kgdb_ops.remove_hw_breakpoint(addr,
+			(int) length, *bpt_type);
+
+	if (error == 0)
+		strcpy(remcom_out_buffer, "OK");
+	else
+		error_packet(remcom_out_buffer, error);
+}
+
+/* Handle the 'C' signal / exception passing packets */
+static int gdb_cmd_exception_pass(struct kgdb_state *ks)
+{
+	/* C09 == pass exception
+	 * C15 == detach kgdb, pass exception
+	 */
+	if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') {
+
+		ks->pass_exception = 1;
+		remcom_in_buffer[0] = 'c';
+
+	} else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') {
+
+		ks->pass_exception = 1;
+		remcom_in_buffer[0] = 'D';
+		remove_all_break();
+		kgdb_connected = 0;
+		return 1;
+
+	} else {
+		error_packet(remcom_out_buffer, -EINVAL);
+		return 0;
+	}
+
+	/* Indicate fall through */
+	return -1;
+}
+
+/*
+ * This function performs all gdbserial command procesing
+ */
+static int gdb_serial_stub(struct kgdb_state *ks)
+{
+	int error = 0;
+	int tmp;
+
+	/* Clear the out buffer. */
+	memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
+
+	if (kgdb_connected) {
+		unsigned char thref[8];
+		char *ptr;
+
+		/*
+		 * Warn debugger if the CPUs are not synced with an 'O'
+		 * packet:
+		 */
+		if (!ks->all_cpus_synced) {
+			kgdb_msg_write("Not all CPUs have been synced for "
+			       "KGDB\n", 39);
+		}
+		/* Reply to host that an exception has occurred */
+		ptr = remcom_out_buffer;
+		*ptr++ = 'T';
+		ptr = pack_hex_byte(ptr, ks->signo);
+		ptr += strlen(strcpy(ptr, "thread:"));
+		int_to_threadref(thref, shadow_pid(current->pid));
+		ptr = pack_threadid(ptr, thref);
+		*ptr++ = ';';
+		put_packet(remcom_out_buffer);
+	}
+
+	kgdb_usethread = kgdb_info[ks->cpu].task;
+	ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid);
+	ks->pass_exception = 0;
+
+	while (1) {
+		error = 0;
+
+		/* Clear the out buffer. */
+		memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
+
+		get_packet(remcom_in_buffer);
+
+		switch (remcom_in_buffer[0]) {
+		case '?': /* gdbserial status */
+			gdb_cmd_status(ks);
+			break;
+		case 'g': /* return the value of the CPU registers */
+			gdb_cmd_getregs(ks);
+			break;
+		case 'G': /* set the value of the CPU registers - return OK */
+			gdb_cmd_setregs(ks);
+			break;
+		case 'm': /* mAA..AA,LLLL  Read LLLL bytes at address AA..AA */
+			gdb_cmd_memread(ks);
+			break;
+		case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
+			gdb_cmd_memwrite(ks);
+			break;
+		case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
+			gdb_cmd_binwrite(ks);
+			break;
+			/* kill or detach. KGDB should treat this like a
+			 * continue.
+			 */
+		case 'D': /* Debugger detach */
+		case 'k': /* Debugger detach via kill */
+			gdb_cmd_detachkill(ks);
+			goto default_handle;
+		case 'R': /* Reboot */
+			if (gdb_cmd_reboot(ks))
+				goto default_handle;
+			break;
+		case 'q': /* query command */
+			gdb_cmd_query(ks);
+			break;
+		case 'H': /* task related */
+			gdb_cmd_task(ks);
+			break;
+		case 'T': /* Query thread status */
+			gdb_cmd_thread(ks);
+			break;
+		case 'z': /* Break point remove */
+		case 'Z': /* Break point set */
+			gdb_cmd_break(ks);
+			break;
+		case 'C': /* Exception passing */
+			tmp = gdb_cmd_exception_pass(ks);
+			if (tmp > 0)
+				goto default_handle;
+			if (tmp == 0)
+				break;
+			/* Fall through on tmp < 0 */
+		case 'c': /* Continue packet */
+		case 's': /* Single step packet */
+			if (kgdb_contthread && kgdb_contthread != current) {
+				/* Can't switch threads in kgdb */
+				error_packet(remcom_out_buffer, -EINVAL);
+				break;
+			}
+			kgdb_activate_sw_breakpoints();
+			/* Fall through to default processing */
+		default:
+default_handle:
+			error = kgdb_arch_handle_exception(ks->ex_vector,
+						ks->signo,
+						ks->err_code,
+						remcom_in_buffer,
+						remcom_out_buffer,
+						ks->linux_regs);
+			/*
+			 * Leave cmd processing on error, detach,
+			 * kill, continue, or single step.
+			 */
+			if (error >= 0 || remcom_in_buffer[0] == 'D' ||
+			    remcom_in_buffer[0] == 'k') {
+				error = 0;
+				goto kgdb_exit;
+			}
+
+		}
+
+		/* reply to the request */
+		put_packet(remcom_out_buffer);
+	}
+
+kgdb_exit:
+	if (ks->pass_exception)
+		error = 1;
+	return error;
+}
+
+static int kgdb_reenter_check(struct kgdb_state *ks)
+{
+	unsigned long addr;
+
+	if (atomic_read(&kgdb_active) != raw_smp_processor_id() + 1)
+		return 0;
+
+	/* Panic on recursive debugger calls: */
+	exception_level++;
+	addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
+	kgdb_deactivate_sw_breakpoints();
+
+	/*
+	 * If the break point removed ok at the place exception
+	 * occurred, try to recover and print a warning to the end
+	 * user because the user planted a breakpoint in a place that
+	 * KGDB needs in order to function.
+	 */
+	if (kgdb_remove_sw_break(addr) == 0) {
+		exception_level = 0;
+		kgdb_skipexception(ks->ex_vector, ks->linux_regs);
+		kgdb_activate_sw_breakpoints();
+		printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed\n");
+		WARN_ON_ONCE(1);
+
+		return 1;
+	}
+	remove_all_break();
+	kgdb_skipexception(ks->ex_vector, ks->linux_regs);
+
+	if (exception_level > 1) {
+		dump_stack();
+		panic("Recursive entry to debugger");
+	}
+
+	printk(KERN_CRIT "KGDB: re-enter exception: ALL breakpoints killed\n");
+	dump_stack();
+	panic("Recursive entry to debugger");
+
+	return 1;
+}
+
+/*
+ * kgdb_handle_exception() - main entry point from a kernel exception
+ *
+ * Locking hierarchy:
+ *	interface locks, if any (begin_session)
+ *	kgdb lock (kgdb_active)
+ *
+ * Note that since we can be in here prior to our cpumask being filled
+ * out, we err on the side of caution and loop over NR_CPUS instead
+ * of a for_each_online_cpu.
+ */
+int
+kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
+{
+	struct kgdb_state kgdb_var;
+	struct kgdb_state *ks = &kgdb_var;
+	unsigned long flags;
+	int error = 0;
+	int i, cpu;
+
+	ks->cpu			= raw_smp_processor_id();
+	ks->all_cpus_synced	= 0;
+	ks->ex_vector		= evector;
+	ks->signo		= signo;
+	ks->ex_vector		= evector;
+	ks->err_code		= ecode;
+	ks->kgdb_usethreadid	= 0;
+	ks->linux_regs		= regs;
+
+	if (kgdb_reenter_check(ks))
+		return 0; /* Ouch, double exception ! */
+
+acquirelock:
+	/*
+	 * Interrupts will be restored by the 'trap return' code, except when
+	 * single stepping.
+	 */
+	local_irq_save(flags);
+
+	cpu = raw_smp_processor_id();
+
+	/*
+	 * Being the process of declaring a master debug processor, the
+	 * goal is to have only one single processor set kgdb_active
+	 * to the number of the cpu + 1.  The atomic variable kgdb_sync is
+	 * used to control the selection.
+	 */
+	while (1) {
+		i = 25;	/* an arbitrary number */
+		if (atomic_read(&kgdb_sync) < 0 &&
+			atomic_inc_and_test(&kgdb_sync)) {
+			atomic_set(&kgdb_active, cpu + 1);
+			break;
+		}
+
+		while (--i)
+			cpu_relax();
+
+		if (atomic_read(&kgdb_cpu_doing_single_step) != -1 &&
+				atomic_read(&kgdb_cpu_doing_single_step) != cpu)
+			udelay(1);
+	}
+
+	/*
+	 * Do not start the debugger connection on this CPU if the last
+	 * instance of the exception handler wanted to come into the
+	 * debugger on a different CPU via a single step
+	 */
+	if (atomic_read(&kgdb_cpu_doing_single_step) != -1 &&
+	    atomic_read(&kgdb_cpu_doing_single_step) != cpu) {
+
+		atomic_set(&kgdb_active, 0);
+		atomic_set(&kgdb_sync, -1);
+		local_irq_restore(flags);
+
+		goto acquirelock;
+	}
+
+	if (!kgdb_io_ready(1)) {
+		error = 1;
+		goto kgdb_restore; /* No I/O connection, so resume the system */
+	}
+
+	/*
+	 * Don't enter if we have hit a removed breakpoint.
+	 */
+	if (kgdb_skipexception(ks->ex_vector, ks->linux_regs))
+		goto kgdb_restore;
+
+	/* Call the I/O driver's pre_exception routine */
+	if (kgdb_io_ops->pre_exception)
+		kgdb_io_ops->pre_exception();
+
+	kgdb_info[ks->cpu].debuggerinfo = ks->linux_regs;
+	kgdb_info[ks->cpu].task = current;
+
+	kgdb_disable_hw_debug(ks->linux_regs);
+
+	/*
+	 * Get the slave CPU lock which will hold all the non-master
+	 * CPU in a spin state while the debugger is active
+	 */
+	if (!kgdb_single_step || !kgdb_contthread) {
+		for (i = 0; i < NR_CPUS; i++)
+			spin_lock(&slave_cpu_locks[i]);
+	}
+
+#ifdef CONFIG_SMP
+	/* Signal the other CPUs to enter kgdb_wait() */
+	if (!kgdb_single_step || !kgdb_contthread)
+		kgdb_roundup_cpus(flags);
+#endif
+
+	/*
+	 * spin_lock code is good enough as a barrier so we don't
+	 * need one here:
+	 */
+	atomic_set(&cpu_in_kgdb[ks->cpu], 1);
+
+	/*
+	 * Wait a reasonable time for the other CPUs to be notified and
+	 * be waiting for us.  Very early on this could be imperfect
+	 * as num_online_cpus() could be 0.
+	 */
+	for (i = 0; i < ROUNDUP_WAIT; i++) {
+		int num = 0;
+		int n;
+
+		for (n = 0; n < NR_CPUS; n++) {
+			if (atomic_read(&cpu_in_kgdb[n]))
+				num++;
+		}
+		if (num >= num_online_cpus()) {
+			ks->all_cpus_synced = 1;
+			break;
+		}
+	}
+
+	/* Master processor is completely in the debugger */
+	kgdb_post_master_code(ks->linux_regs, ks->ex_vector, ks->err_code);
+	kgdb_deactivate_sw_breakpoints();
+	kgdb_single_step = 0;
+	kgdb_contthread = NULL;
+	exception_level = 0;
+
+	/* Talk to debugger with gdbserial protocol */
+	error = gdb_serial_stub(ks);
+
+	/* Call the I/O driver's post_exception routine */
+	if (kgdb_io_ops->post_exception)
+		kgdb_io_ops->post_exception();
+
+	kgdb_info[ks->cpu].debuggerinfo = NULL;
+	kgdb_info[ks->cpu].task = NULL;
+	atomic_set(&cpu_in_kgdb[ks->cpu], 0);
+
+	if (!kgdb_single_step || !kgdb_contthread) {
+		for (i = NR_CPUS-1; i >= 0; i--)
+			spin_unlock(&slave_cpu_locks[i]);
+		/*
+		 * Wait till all the CPUs have quit
+		 * from the debugger.
+		 */
+		for (i = 0; i < NR_CPUS; i++) {
+			while (atomic_read(&cpu_in_kgdb[i])) {
+				int j = 10;	/* an arbitrary number */
+
+				while (--j)
+					cpu_relax();
+			}
+		}
+	}
+
+#ifdef CONFIG_SMP
+	/*
+	 * This delay has a real purpose.  The problem is that if you
+	 * are single-stepping, you are sending an NMI to all the
+	 * other CPUs to stop them.  Interrupts come in, but don't get
+	 * handled.  Then you let them go just long enough to get into
+	 * their interrupt routines and use up some stack. You stop them
+	 * again, and then do the same thing.  After a while you blow
+	 * the stack on the other CPUs. This delay gives some time for
+	 * interrupts to be cleared out on the other CPUs.
+	 */
+	if (kgdb_single_step)
+		mdelay(2);
+#endif
+kgdb_restore:
+	/* Free kgdb_active */
+	atomic_set(&kgdb_active, 0);
+	atomic_set(&kgdb_sync, -1);
+	local_irq_restore(flags);
+
+	return error;
+}
+
+/*
+ * GDB places a breakpoint at this function to know dynamically
+ * loaded objects. It's not defined static so that only one instance with this
+ * name exists in the kernel.
+ */
+
+int module_event(struct notifier_block *self, unsigned long val, void *data)
+{
+	return 0;
+}
+
+static struct notifier_block kgdb_module_load_nb = {
+	.notifier_call	= module_event,
+};
+
+int kgdb_nmicallback(int cpu, void *regs)
+{
+#ifdef CONFIG_SMP
+	if (!atomic_read(&cpu_in_kgdb[cpu]) &&
+		atomic_read(&kgdb_active) != (cpu + 1)) {
+		kgdb_wait((struct pt_regs *)regs);
+		return 0;
+	}
+#endif
+	return 1;
+}
+
+/*
+ * This is called when a panic happens.  All we need to do is
+ * kgdb_breakpoint().
+ */
+static int
+kgdb_panic_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
+{
+	if (atomic_read(&kgdb_active) != 0) {
+		printk(KERN_ERR "KGDB: Cannot handle panic while"
+				"debugger active\n");
+		dump_stack();
+		return NOTIFY_DONE;
+	}
+	printk(KERN_ERR "kgdb panic point\n");
+	kgdb_breakpoint();
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block kgdb_panic_notifier = {
+	.notifier_call	= kgdb_panic_notify,
+};
+
+#ifdef CONFIG_KGDB_CONSOLE_OUTPUT
+
+void kgdb_console_write(struct console *co, const char *s, unsigned count)
+{
+	unsigned long flags;
+
+	/* If we're debugging, or KGDB has not connected, don't try
+	 * and print. */
+	if (!kgdb_connected || atomic_read(&kgdb_active) != 0)
+		return;
+
+	local_irq_save(flags);
+	kgdb_msg_write(s, count);
+	local_irq_restore(flags);
+}
+
+static struct console kgdbcons = {
+	.name		= "kgdb",
+	.write		= kgdb_console_write,
+	.flags		= CON_PRINTBUFFER | CON_ENABLED,
+	.index		= -1,
+}
+;
+#endif
+
+#ifdef CONFIG_MAGIC_SYSRQ
+static void sysrq_handle_gdb(int key, struct tty_struct *tty)
+{
+	if (!kgdb_io_ops) {
+		printk(KERN_CRIT "ERROR: No KGDB I/O module available\n");
+		return;
+	}
+	if (!kgdb_connected)
+		printk(KERN_CRIT "Entering KGDB\n");
+
+	kgdb_breakpoint();
+}
+
+static struct sysrq_key_op sysrq_gdb_op = {
+	.handler	= sysrq_handle_gdb,
+	.help_msg	= "Gdb",
+	.action_msg	= "GDB",
+};
+#endif
+
+static void kgdb_register_callbacks(void)
+{
+	if (!kgdb_io_module_registered) {
+		kgdb_io_module_registered = 1;
+		kgdb_arch_init();
+		atomic_notifier_chain_register(&panic_notifier_list,
+					&kgdb_panic_notifier);
+		register_module_notifier(&kgdb_module_load_nb);
+		register_reboot_notifier(&kgdb_reboot_notifier);
+#ifdef CONFIG_MAGIC_SYSRQ
+		register_sysrq_key('g', &sysrq_gdb_op);
+#endif
+#ifdef CONFIG_KGDB_CONSOLE_OUTPUT
+		/* Initialize the console registration */
+		register_console(&kgdbcons);
+#endif
+	}
+}
+
+static void kgdb_unregister_callbacks(void)
+{
+	/*
+	 * When this routine is called KGDB should unregister from the
+	 * panic handler and clean up, making sure it is not handling any
+	 * break exceptions at the time.
+	 */
+	if (kgdb_io_module_registered) {
+		kgdb_io_module_registered = 0;
+		kgdb_arch_uninit();
+		atomic_notifier_chain_unregister(&panic_notifier_list,
+					  &kgdb_panic_notifier);
+		unregister_module_notifier(&kgdb_module_load_nb);
+		unregister_reboot_notifier(&kgdb_reboot_notifier);
+#ifdef CONFIG_MAGIC_SYSRQ
+		unregister_sysrq_key('g', &sysrq_gdb_op);
+#endif
+#ifdef CONFIG_KGDB_CONSOLE_OUTPUT
+		/* Initialize the console registration */
+		unregister_console(&kgdbcons);
+#endif
+	}
+}
+
+static void kgdb_initial_breakpoint(void)
+{
+	kgdb_break_asap = 0;
+
+	printk(KERN_CRIT "kgdb: Waiting for connection from remote gdb...\n");
+	kgdb_breakpoint();
+}
+
+/**
+ *	kkgdb_register_io_module - register KGDB IO module
+ *	@new_kgdb_io_ops: the io ops vector
+ *
+ *	Register it with the KGDB core.
+ */
+int kgdb_register_io_module(struct kgdb_io *new_kgdb_io_ops)
+{
+	int err;
+
+	spin_lock(&kgdb_registration_lock);
+
+	if (kgdb_io_ops) {
+		spin_unlock(&kgdb_registration_lock);
+
+		printk(KERN_ERR "kgdb: Another I/O driver is already "
+				"registered with KGDB.\n");
+		return -EBUSY;
+	}
+
+	if (new_kgdb_io_ops->init) {
+		err = new_kgdb_io_ops->init();
+		if (err) {
+			spin_unlock(&kgdb_registration_lock);
+			return err;
+		}
+	}
+
+	kgdb_io_ops = new_kgdb_io_ops;
+
+	spin_unlock(&kgdb_registration_lock);
+
+	printk(KERN_INFO "kgdb: Registered I/O driver %s.\n",
+	       new_kgdb_io_ops->name);
+
+	/* Arm KGDB now. */
+	kgdb_register_callbacks();
+
+	if (kgdb_break_asap)
+		kgdb_initial_breakpoint();
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kgdb_register_io_module);
+
+/**
+ *	kkgdb_unregister_io_module - unregister KGDB IO module
+ *	@old_kgdb_io_ops: the io ops vector
+ *
+ *	Unregister it with the KGDB core.
+ */
+void kgdb_unregister_io_module(struct kgdb_io *old_kgdb_io_ops)
+{
+	BUG_ON(kgdb_connected);
+
+	/*
+	 * KGDB is no longer able to communicate out, so
+	 * unregister our callbacks and reset state.
+	 */
+	kgdb_unregister_callbacks();
+
+	spin_lock(&kgdb_registration_lock);
+
+	WARN_ON_ONCE(kgdb_io_ops != old_kgdb_io_ops);
+	kgdb_io_ops = NULL;
+
+	spin_unlock(&kgdb_registration_lock);
+
+	printk(KERN_INFO
+		"kgdb: Unregistered I/O driver %s, debugger disabled.\n",
+		old_kgdb_io_ops->name);
+}
+EXPORT_SYMBOL_GPL(kgdb_unregister_io_module);
+
+/**
+ * kgdb_breakpoint - generate breakpoint exception
+ *
+ * This function will generate a breakpoint exception.  It is used at the
+ * beginning of a program to sync up with a debugger and can be used
+ * otherwise as a quick means to stop program execution and "break" into
+ * the debugger.
+ */
+void kgdb_breakpoint(void)
+{
+	atomic_set(&kgdb_setting_breakpoint, 1);
+	wmb(); /* Sync point before breakpoint */
+	arch_kgdb_breakpoint();
+	wmb(); /* Sync point after breakpoint */
+	atomic_set(&kgdb_setting_breakpoint, 0);
+}
+EXPORT_SYMBOL_GPL(kgdb_breakpoint);
+
+static int
+kgdb_notify_reboot(struct notifier_block *this, unsigned long code, void *x)
+{
+	unsigned long flags;
+
+	/*
+	 * If we're debugging, or KGDB has not connected, don't try
+	 * and print:
+	 */
+	if (!kgdb_connected || atomic_read(&kgdb_active) != 0)
+		return 0;
+
+	if (code == SYS_RESTART || code == SYS_HALT || code == SYS_POWER_OFF) {
+		local_irq_save(flags);
+		put_packet("X00");
+		kgdb_connected = 0;
+		local_irq_restore(flags);
+	}
+	return NOTIFY_DONE;
+}
+
+static int __init opt_kgdb_wait(char *str)
+{
+	kgdb_break_asap = 1;
+
+	if (kgdb_io_module_registered)
+		kgdb_initial_breakpoint();
+
+	return 0;
+}
+
+early_param("kgdbwait", opt_kgdb_wait);
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index d41ef6b..97a152c 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -32,6 +32,7 @@
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/kobject.h>
+#include <linux/pid.h>
 #include <linux/net.h>
 #include <linux/sysrq.h>
 #include <linux/highuid.h>
@@ -71,7 +72,6 @@ extern int max_threads;
 extern int core_uses_pid;
 extern int suid_dumpable;
 extern char core_pattern[];
-extern int pid_max;
 extern int min_free_kbytes;
 extern int pid_max_min, pid_max_max;
 extern int sysctl_drop_caches;
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index a370fe8..a904916 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -618,3 +618,5 @@ config PROVIDE_OHCI1394_DMA_INIT
 	  See Documentation/debugging-via-ohci1394.txt for more information.
 
 source "samples/Kconfig"
+
+source "lib/Kconfig.kgdb"
diff --git a/lib/Kconfig.kgdb b/lib/Kconfig.kgdb
new file mode 100644
index 0000000..a739e9d
--- /dev/null
+++ b/lib/Kconfig.kgdb
@@ -0,0 +1,40 @@
+
+menuconfig KGDB
+	bool "KGDB: kernel debugging with remote gdb"
+	select FRAME_POINTER
+	depends on HAVE_ARCH_KGDB
+	depends on DEBUG_KERNEL && EXPERIMENTAL
+	help
+	  If you say Y here, it will be possible to remotely debug the
+	  kernel using gdb.  Documentation of kernel debugger is available
+	  at http://kgdb.sourceforge.net as well as in DocBook form
+	  in Documentation/DocBook/.  If unsure, say N.
+
+config HAVE_ARCH_KGDB_SHADOW_INFO
+	bool
+
+config HAVE_ARCH_KGDB
+	bool
+
+config KGDB_CONSOLE_OUTPUT
+	bool "KGDB: Console messages through gdb"
+	depends on KGDB
+	help
+	  If you say Y here, console messages will appear through gdb.
+	  Other consoles such as tty or ttyS will continue to work as usual.
+	  Note that if you use this in conjunction with KGDBOE, if the
+	  ethernet driver runs into an error condition during use with KGDB,
+	  it is possible to hit an infinite recursion, causing the kernel
+	  to crash, and typically reboot.  For this reason, it is preferable
+	  to use NETCONSOLE in conjunction with KGDBOE instead of
+	  KGDB_CONSOLE.
+
+config KGDB_SERIAL_CONSOLE
+	tristate "KGDB: use kgdb over the serial console"
+	depends on KGDB
+	select CONSOLE_POLL
+	select MAGIC_SYSRQ
+	default y
+	help
+	  Share a serial console with kgdb. Sysrq-g must be used
+	  to break in initially.
diff --git a/mm/Makefile b/mm/Makefile
index 9f117ba..fb9e7ac 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -8,7 +8,7 @@ mmu-$(CONFIG_MMU)	:= fremap.o highmem.o madvise.o memory.o mincore.o \
 			   vmalloc.o
 
 obj-y			:= bootmem.o filemap.o mempool.o oom_kill.o fadvise.o \
-			   page_alloc.o page-writeback.o pdflush.o \
+			   maccess.o page_alloc.o page-writeback.o pdflush.o \
 			   readahead.o swap.o truncate.o vmscan.o \
 			   prio_tree.o util.o mmzone.o vmstat.o backing-dev.o \
 			   page_isolation.o $(mmu-y)
diff --git a/mm/maccess.c b/mm/maccess.c
new file mode 100644
index 0000000..24f81b9
--- /dev/null
+++ b/mm/maccess.c
@@ -0,0 +1,49 @@
+/*
+ * Access kernel memory without faulting.
+ */
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+
+/**
+ * probe_kernel_read(): safely attempt to read from a location
+ * @dst: pointer to the buffer that shall take the data
+ * @src: address to read from
+ * @size: size of the data chunk
+ *
+ * Safely read from address @src to the buffer at @dst.  If a kernel fault
+ * happens, handle that and return -EFAULT.
+ */
+long probe_kernel_read(void *dst, void *src, size_t size)
+{
+	long ret;
+
+	pagefault_disable();
+	ret = __copy_from_user_inatomic(dst,
+			(__force const void __user *)src, size);
+	pagefault_enable();
+
+	return ret ? -EFAULT : 0;
+}
+EXPORT_SYMBOL_GPL(probe_kernel_read);
+
+/**
+ * probe_kernel_write(): safely attempt to write to a location
+ * @dst: address to write to
+ * @src: pointer to the data that shall be written
+ * @size: size of the data chunk
+ *
+ * Safely write to address @dst from the buffer at @src.  If a kernel fault
+ * happens, handle that and return -EFAULT.
+ */
+long probe_kernel_write(void *dst, void *src, size_t size)
+{
+	long ret;
+
+	pagefault_disable();
+	ret = __copy_to_user_inatomic((__force void __user *)dst, src, size);
+	pagefault_enable();
+
+	return ret ? -EFAULT : 0;
+}
+EXPORT_SYMBOL_GPL(probe_kernel_write);

Re: [git pull] kgdb-light -v8,

[Jan Kiszka]

Ingo Molnar wrote:
> In any case, if there are any open issues we are very much ready and 
> willing to address them now or after any potential upstream merge of 
> this codebase. This has meanwhile become one of the best-reviewed pieces 
> of kernel code in living memory ;-)
> 

I spotted one... :)

> +int __weak kgdb_validate_break_address(unsigned long addr)
> +{
> +	char tmp_variable[BREAK_INSTR_SIZE];
> +
> +	return probe_kernel_read((char *)addr, tmp_variable, BREAK_INSTR_SIZE);

...dst and src are twisted. Fix below (should make sw-breakpoints work
again).

Jan


diff --git a/kernel/kgdb.c b/kernel/kgdb.c
index dce89d1..10fe113 100644
--- a/kernel/kgdb.c
+++ b/kernel/kgdb.c
@@ -153,14 +153,14 @@ int __weak kgdb_validate_break_address(unsigned long addr)
 {
 	char tmp_variable[BREAK_INSTR_SIZE];
 
-	return probe_kernel_read((char *)addr, tmp_variable, BREAK_INSTR_SIZE);
+	return probe_kernel_read(tmp_variable, (char *)addr, BREAK_INSTR_SIZE);
 }
 
 int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr)
 {
 	int err;
 
-	err = probe_kernel_read((char *)addr, saved_instr, BREAK_INSTR_SIZE);
+	err = probe_kernel_read(saved_instr, (char *)addr, BREAK_INSTR_SIZE);
 	if (err)
 		return err;
 

Re: [git pull] kgdb-light -v8,

[Ingo Molnar]

* Jan Kiszka <jan.kiszka@siemens.com> wrote:

> Ingo Molnar wrote:
> > In any case, if there are any open issues we are very much ready and 
> > willing to address them now or after any potential upstream merge of 
> > this codebase. This has meanwhile become one of the best-reviewed pieces 
> > of kernel code in living memory ;-)
> > 
> 
> I spotted one... :)

thanks, applied :-) Merged, uploaded the updated tree to the usual 
place. New tip of head is 59b64c80d706ae3504ccc76a9c00cdfea4a10701.

	Ingo

Re: [git pull] kgdb-light -v8, (was: Re: kgdb in git-x86#mm review)

[Andi Kleen]

> after a quick glance i'm happy to conclude that all but one of Andi's 

At least the weird in_interrupt_stack() code seems to be still
in there.

I also still see a lot of open coded hex manipulation.

The synchronization code looks as bad as it was before.

The getthread magic pids are also still in there. What is that
good for?  

The notifiers are also still run with interrupts enabled,
so could in theory be preempted (only in some very exotic cases though)

The cpu hotplug races are still there I think

I have not rechecked everything else.

-Andi

[git pull] kgdb-light -v9

[Ingo Molnar]

i've uploaded kgdb-light -v9, it can be pulled from:

   git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-kgdb.git

find the shortlog, diffstat, full patch below.

There are a number of changes in -v9 - a patch from Jason to clean up 
kernel-messages-over-the-kgdb-console behavior and a bugfix from Jan.

Here's how i addressed the review feedback from Andi Kleen:

> At least the weird in_interrupt_stack() code seems to be still in 
> there.

fixed. (That code is gone now - the pt_regs passed in to the notifier 
points to the right kind of register context already, so the whole 
shadow task business on 64-bit was an unnecessary complication - as you 
suspected it. With it went another bunch of kernel/kgdb.c complication 
as well.)

> The synchronization code looks as bad as it was before.

i reworked and cleaned up all the kgdb locking code completely. No more 
NR_CPUS spinlocks, there's now proper use of barriers, etc. No more 
silly "timeouts" for locking either ... There's now a very well-defined 
and clean locking state-machine for the primary CPU and the secondary 
CPUs. I re-tested it all on SMP hardware as well.

> The getthread magic pids are also still in there. What is that good 
> for?

i fixed the shadow thread bits which where harmless but unnecessary.

> The notifiers are also still run with interrupts enabled, so could in 
> theory be preempted (only in some very exotic cases though)

exotic indeed - but nevertheless i fixed this too.

> I also still see a lot of open coded hex manipulation.

previously Mark indicated some sort of sprintf return value breakage he 
observed, and kgdb would rely on sprintf return values so i'm inclined 
to leave it as-is. We can fix that later, it's not critical.

> The cpu hotplug races are still there I think

i fixed them too.

thanks for your suggestions, anything else you can think of?

	Ingo

------------------>
Ingo Molnar (3):
      pids: add pid_max prototype
      uaccess: add probe_kernel_write()
      x86: kgdb support

Jason Wessel (3):
      kgdb: core
      consoles: polling support, kgdboc
      kgdb: document parameters

 Documentation/kernel-parameters.txt |    5 +
 arch/x86/Kconfig                    |    1 +
 arch/x86/kernel/Makefile            |    1 +
 arch/x86/kernel/kgdb.c              |  555 ++++++++++++
 drivers/char/tty_io.c               |   47 +
 drivers/serial/8250.c               |   58 ++
 drivers/serial/Kconfig              |    3 +
 drivers/serial/Makefile             |    1 +
 drivers/serial/kgdboc.c             |  163 ++++
 drivers/serial/serial_core.c        |   70 ++-
 include/asm-x86/kgdb.h              |   81 ++
 include/linux/kgdb.h                |  271 ++++++
 include/linux/pid.h                 |    2 +
 include/linux/serial_core.h         |    4 +
 include/linux/tty_driver.h          |   12 +
 include/linux/uaccess.h             |   22 +
 kernel/Makefile                     |    1 +
 kernel/kgdb.c                       | 1663 +++++++++++++++++++++++++++++++++++
 kernel/sysctl.c                     |    2 +-
 lib/Kconfig.debug                   |    2 +
 lib/Kconfig.kgdb                    |   27 +
 mm/Makefile                         |    2 +-
 mm/maccess.c                        |   49 +
 23 files changed, 3037 insertions(+), 5 deletions(-)
 create mode 100644 arch/x86/kernel/kgdb.c
 create mode 100644 drivers/serial/kgdboc.c
 create mode 100644 include/asm-x86/kgdb.h
 create mode 100644 include/linux/kgdb.h
 create mode 100644 kernel/kgdb.c
 create mode 100644 lib/Kconfig.kgdb
 create mode 100644 mm/maccess.c

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index a4fc7fc..6e97307 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -930,6 +930,11 @@ and is between 256 and 4096 characters. It is defined in the file
 	kstack=N	[X86-32,X86-64] Print N words from the kernel stack
 			in oops dumps.
 
+	kgdboc=		[HW] kgdb over consoles.
+			Requires a tty driver that supports console polling.
+			(only serial suported for now)
+			Format: <serial_device>[,baud]
+
 	l2cr=		[PPC]
 
 	lapic		[X86-32,APIC] Enable the local APIC even if BIOS
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index aaed1a3..c8dd8f9 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -21,6 +21,7 @@ config X86
 	select HAVE_IDE
 	select HAVE_OPROFILE
 	select HAVE_KPROBES
+	select HAVE_ARCH_KGDB
 
 config GENERIC_LOCKBREAK
 	def_bool n
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 76ec0f8..4cd39cd 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -58,6 +58,7 @@ obj-$(CONFIG_MODULES)		+= module_$(BITS).o
 obj-$(CONFIG_ACPI_SRAT) 	+= srat_32.o
 obj-$(CONFIG_EFI) 		+= efi.o efi_$(BITS).o efi_stub_$(BITS).o
 obj-$(CONFIG_DOUBLEFAULT) 	+= doublefault_32.o
+obj-$(CONFIG_KGDB)		+= kgdb.o
 obj-$(CONFIG_VM86)		+= vm86_32.o
 obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
 
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
new file mode 100644
index 0000000..18034d5
--- /dev/null
+++ b/arch/x86/kernel/kgdb.c
@@ -0,0 +1,555 @@
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ */
+
+/*
+ * Copyright (C) 2004 Amit S. Kale <amitkale@linsyssoft.com>
+ * Copyright (C) 2000-2001 VERITAS Software Corporation.
+ * Copyright (C) 2002 Andi Kleen, SuSE Labs
+ * Copyright (C) 2004 LinSysSoft Technologies Pvt. Ltd.
+ * Copyright (C) 2007 MontaVista Software, Inc.
+ * Copyright (C) 2007-2008 Jason Wessel, Wind River Systems, Inc.
+ */
+/****************************************************************************
+ *  Contributor:     Lake Stevens Instrument Division$
+ *  Written by:      Glenn Engel $
+ *  Updated by:	     Amit Kale<akale@veritas.com>
+ *  Updated by:	     Tom Rini <trini@kernel.crashing.org>
+ *  Updated by:	     Jason Wessel <jason.wessel@windriver.com>
+ *  Modified for 386 by Jim Kingdon, Cygnus Support.
+ *  Origianl kgdb, compatibility with 2.1.xx kernel by
+ *  David Grothe <dave@gcom.com>
+ *  Integrated into 2.2.5 kernel by Tigran Aivazian <tigran@sco.com>
+ *  X86_64 changes from Andi Kleen's patch merged by Jim Houston
+ */
+#include <linux/spinlock.h>
+#include <linux/kdebug.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/ptrace.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/kgdb.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+
+#include <asm/apicdef.h>
+#include <asm/system.h>
+
+#ifdef CONFIG_X86_32
+# include <mach_ipi.h>
+#else
+# include <asm/mach_apic.h>
+#endif
+
+/*
+ * Put the error code here just in case the user cares:
+ */
+static int gdb_x86errcode;
+
+/*
+ * Likewise, the vector number here (since GDB only gets the signal
+ * number through the usual means, and that's not very specific):
+ */
+static int gdb_x86vector = -1;
+
+/**
+ *	pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs
+ *	@gdb_regs: A pointer to hold the registers in the order GDB wants.
+ *	@regs: The &struct pt_regs of the current process.
+ *
+ *	Convert the pt_regs in @regs into the format for registers that
+ *	GDB expects, stored in @gdb_regs.
+ */
+void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+	gdb_regs[GDB_AX]	= regs->ax;
+	gdb_regs[GDB_BX]	= regs->bx;
+	gdb_regs[GDB_CX]	= regs->cx;
+	gdb_regs[GDB_DX]	= regs->dx;
+	gdb_regs[GDB_SI]	= regs->si;
+	gdb_regs[GDB_DI]	= regs->di;
+	gdb_regs[GDB_BP]	= regs->bp;
+	gdb_regs[GDB_PS]	= regs->flags;
+	gdb_regs[GDB_PC]	= regs->ip;
+#ifdef CONFIG_X86_32
+	gdb_regs[GDB_DS]	= regs->ds;
+	gdb_regs[GDB_ES]	= regs->es;
+	gdb_regs[GDB_CS]	= regs->cs;
+	gdb_regs[GDB_SS]	= __KERNEL_DS;
+	gdb_regs[GDB_FS]	= 0xFFFF;
+	gdb_regs[GDB_GS]	= 0xFFFF;
+#else
+	gdb_regs[GDB_R8]	= regs->r8;
+	gdb_regs[GDB_R9]	= regs->r9;
+	gdb_regs[GDB_R10]	= regs->r10;
+	gdb_regs[GDB_R11]	= regs->r11;
+	gdb_regs[GDB_R12]	= regs->r12;
+	gdb_regs[GDB_R13]	= regs->r13;
+	gdb_regs[GDB_R14]	= regs->r14;
+	gdb_regs[GDB_R15]	= regs->r15;
+#endif
+	gdb_regs[GDB_SP]	= regs->sp;
+}
+
+/**
+ *	sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs
+ *	@gdb_regs: A pointer to hold the registers in the order GDB wants.
+ *	@p: The &struct task_struct of the desired process.
+ *
+ *	Convert the register values of the sleeping process in @p to
+ *	the format that GDB expects.
+ *	This function is called when kgdb does not have access to the
+ *	&struct pt_regs and therefore it should fill the gdb registers
+ *	@gdb_regs with what has	been saved in &struct thread_struct
+ *	thread field during switch_to.
+ */
+void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
+{
+	gdb_regs[GDB_AX]	= 0;
+	gdb_regs[GDB_BX]	= 0;
+	gdb_regs[GDB_CX]	= 0;
+	gdb_regs[GDB_DX]	= 0;
+	gdb_regs[GDB_SI]	= 0;
+	gdb_regs[GDB_DI]	= 0;
+	gdb_regs[GDB_BP]	= *(unsigned long *)p->thread.sp;
+#ifdef CONFIG_X86_32
+	gdb_regs[GDB_DS]	= __KERNEL_DS;
+	gdb_regs[GDB_ES]	= __KERNEL_DS;
+	gdb_regs[GDB_PS]	= 0;
+	gdb_regs[GDB_CS]	= __KERNEL_CS;
+	gdb_regs[GDB_PC]	= p->thread.ip;
+	gdb_regs[GDB_SS]	= __KERNEL_DS;
+	gdb_regs[GDB_FS]	= 0xFFFF;
+	gdb_regs[GDB_GS]	= 0xFFFF;
+#else
+	gdb_regs[GDB_PS]	= *(unsigned long *)(p->thread.sp + 8);
+	gdb_regs[GDB_PC]	= 0;
+	gdb_regs[GDB_R8]	= 0;
+	gdb_regs[GDB_R9]	= 0;
+	gdb_regs[GDB_R10]	= 0;
+	gdb_regs[GDB_R11]	= 0;
+	gdb_regs[GDB_R12]	= 0;
+	gdb_regs[GDB_R13]	= 0;
+	gdb_regs[GDB_R14]	= 0;
+	gdb_regs[GDB_R15]	= 0;
+#endif
+	gdb_regs[GDB_SP]	= p->thread.sp;
+}
+
+/**
+ *	gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs.
+ *	@gdb_regs: A pointer to hold the registers we've received from GDB.
+ *	@regs: A pointer to a &struct pt_regs to hold these values in.
+ *
+ *	Convert the GDB regs in @gdb_regs into the pt_regs, and store them
+ *	in @regs.
+ */
+void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+	regs->ax		= gdb_regs[GDB_AX];
+	regs->bx		= gdb_regs[GDB_BX];
+	regs->cx		= gdb_regs[GDB_CX];
+	regs->dx		= gdb_regs[GDB_DX];
+	regs->si		= gdb_regs[GDB_SI];
+	regs->di		= gdb_regs[GDB_DI];
+	regs->bp		= gdb_regs[GDB_BP];
+	regs->flags		= gdb_regs[GDB_PS];
+	regs->ip		= gdb_regs[GDB_PC];
+#ifdef CONFIG_X86_32
+	regs->ds		= gdb_regs[GDB_DS];
+	regs->es		= gdb_regs[GDB_ES];
+	regs->cs		= gdb_regs[GDB_CS];
+#else
+	regs->r8		= gdb_regs[GDB_R8];
+	regs->r9		= gdb_regs[GDB_R9];
+	regs->r10		= gdb_regs[GDB_R10];
+	regs->r11		= gdb_regs[GDB_R11];
+	regs->r12		= gdb_regs[GDB_R12];
+	regs->r13		= gdb_regs[GDB_R13];
+	regs->r14		= gdb_regs[GDB_R14];
+	regs->r15		= gdb_regs[GDB_R15];
+#endif
+}
+
+static struct hw_breakpoint {
+	unsigned		enabled;
+	unsigned		type;
+	unsigned		len;
+	unsigned long		addr;
+} breakinfo[4];
+
+static void kgdb_correct_hw_break(void)
+{
+	unsigned long dr7;
+	int correctit = 0;
+	int breakbit;
+	int breakno;
+
+	get_debugreg(dr7, 7);
+	for (breakno = 0; breakno < 4; breakno++) {
+		breakbit = 2 << (breakno << 1);
+		if (!(dr7 & breakbit) && breakinfo[breakno].enabled) {
+			correctit = 1;
+			dr7 |= breakbit;
+			dr7 &= ~(0xf0000 << (breakno << 2));
+			dr7 |= ((breakinfo[breakno].len << 2) |
+				 breakinfo[breakno].type) <<
+			       ((breakno << 2) + 16);
+			if (breakno >= 0 && breakno <= 3)
+				set_debugreg(breakinfo[breakno].addr, breakno);
+
+		} else {
+			if ((dr7 & breakbit) && !breakinfo[breakno].enabled) {
+				correctit = 1;
+				dr7 &= ~breakbit;
+				dr7 &= ~(0xf0000 << (breakno << 2));
+			}
+		}
+	}
+	if (correctit)
+		set_debugreg(dr7, 7);
+}
+
+static int
+kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
+{
+	int i;
+
+	for (i = 0; i < 4; i++)
+		if (breakinfo[i].addr == addr && breakinfo[i].enabled)
+			break;
+	if (i == 4)
+		return -1;
+
+	breakinfo[i].enabled = 0;
+
+	return 0;
+}
+
+static void kgdb_remove_all_hw_break(void)
+{
+	int i;
+
+	for (i = 0; i < 4; i++)
+		memset(&breakinfo[i], 0, sizeof(struct hw_breakpoint));
+}
+
+static int
+kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
+{
+	unsigned type;
+	int i;
+
+	for (i = 0; i < 4; i++)
+		if (!breakinfo[i].enabled)
+			break;
+	if (i == 4)
+		return -1;
+
+	switch (bptype) {
+	case BP_HARDWARE_BREAKPOINT:
+		type = 0;
+		len  = 1;
+		break;
+	case BP_WRITE_WATCHPOINT:
+		type = 1;
+		break;
+	case BP_ACCESS_WATCHPOINT:
+		type = 3;
+		break;
+	default:
+		return -1;
+	}
+
+	if (len == 1 || len == 2 || len == 4)
+		breakinfo[i].len  = len - 1;
+	else
+		return -1;
+
+	breakinfo[i].enabled = 1;
+	breakinfo[i].addr = addr;
+	breakinfo[i].type = type;
+
+	return 0;
+}
+
+/**
+ *	kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
+ *	@regs: Current &struct pt_regs.
+ *
+ *	This function will be called if the particular architecture must
+ *	disable hardware debugging while it is processing gdb packets or
+ *	handling exception.
+ */
+void kgdb_disable_hw_debug(struct pt_regs *regs)
+{
+	/* Disable hardware debugging while we are in kgdb: */
+	set_debugreg(0UL, 7);
+}
+
+/**
+ *	kgdb_post_primary_code - Save error vector/code numbers.
+ *	@regs: Original pt_regs.
+ *	@e_vector: Original error vector.
+ *	@err_code: Original error code.
+ *
+ *	This is needed on architectures which support SMP and KGDB.
+ *	This function is called after all the slave cpus have been put
+ *	to a know spin state and the primary CPU has control over KGDB.
+ */
+void kgdb_post_primary_code(struct pt_regs *regs, int e_vector, int err_code)
+{
+	/* primary processor is completely in the debugger */
+	gdb_x86vector = e_vector;
+	gdb_x86errcode = err_code;
+}
+
+#ifdef CONFIG_SMP
+/**
+ *	kgdb_roundup_cpus - Get other CPUs into a holding pattern
+ *	@flags: Current IRQ state
+ *
+ *	On SMP systems, we need to get the attention of the other CPUs
+ *	and get them be in a known state.  This should do what is needed
+ *	to get the other CPUs to call kgdb_wait(). Note that on some arches,
+ *	the NMI approach is not used for rounding up all the CPUs. For example,
+ *	in case of MIPS, smp_call_function() is used to roundup CPUs. In
+ *	this case, we have to make sure that interrupts are enabled before
+ *	calling smp_call_function(). The argument to this function is
+ *	the flags that will be used when restoring the interrupts. There is
+ *	local_irq_save() call before kgdb_roundup_cpus().
+ *
+ *	On non-SMP systems, this is not called.
+ */
+void kgdb_roundup_cpus(unsigned long flags)
+{
+	send_IPI_allbutself(APIC_DM_NMI);
+}
+#endif
+
+/**
+ *	kgdb_arch_handle_exception - Handle architecture specific GDB packets.
+ *	@vector: The error vector of the exception that happened.
+ *	@signo: The signal number of the exception that happened.
+ *	@err_code: The error code of the exception that happened.
+ *	@remcom_in_buffer: The buffer of the packet we have read.
+ *	@remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
+ *	@regs: The &struct pt_regs of the current process.
+ *
+ *	This function MUST handle the 'c' and 's' command packets,
+ *	as well packets to set / remove a hardware breakpoint, if used.
+ *	If there are additional packets which the hardware needs to handle,
+ *	they are handled here.  The code should return -1 if it wants to
+ *	process more packets, and a %0 or %1 if it wants to exit from the
+ *	kgdb callback.
+ */
+int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
+			       char *remcomInBuffer, char *remcomOutBuffer,
+			       struct pt_regs *linux_regs)
+{
+	unsigned long addr;
+	unsigned long dr6;
+	char *ptr;
+	int newPC;
+
+	switch (remcomInBuffer[0]) {
+	case 'c':
+	case 's':
+		/* try to read optional parameter, pc unchanged if no parm */
+		ptr = &remcomInBuffer[1];
+		if (kgdb_hex2long(&ptr, &addr))
+			linux_regs->ip = addr;
+		newPC = linux_regs->ip;
+
+		/* clear the trace bit */
+		linux_regs->flags &= ~TF_MASK;
+		atomic_set(&kgdb_cpu_doing_single_step, -1);
+
+		/* set the trace bit if we're stepping */
+		if (remcomInBuffer[0] == 's') {
+			linux_regs->flags |= TF_MASK;
+			kgdb_single_step = 1;
+			if (kgdb_contthread) {
+				atomic_set(&kgdb_cpu_doing_single_step,
+					   raw_smp_processor_id());
+			}
+		}
+
+		get_debugreg(dr6, 6);
+		if (!(dr6 & 0x4000)) {
+			int breakno;
+
+			for (breakno = 0; breakno < 4; breakno++) {
+				if (dr6 & (1 << breakno) &&
+				    breakinfo[breakno].type == 0) {
+					/* Set restore flag: */
+					linux_regs->flags |= X86_EFLAGS_RF;
+					break;
+				}
+			}
+		}
+		set_debugreg(0UL, 6);
+		kgdb_correct_hw_break();
+
+		return 0;
+	}
+
+	/* this means that we do not want to exit from the handler: */
+	return -1;
+}
+
+static inline int
+single_step_cont(struct pt_regs *regs, struct die_args *args)
+{
+	/*
+	 * Single step exception from kernel space to user space so
+	 * eat the exception and continue the process:
+	 */
+	printk(KERN_ERR "KGDB: trap/step from kernel to user space, "
+			"resuming...\n");
+	kgdb_arch_handle_exception(args->trapnr, args->signr,
+				   args->err, "c", "", regs);
+
+	return NOTIFY_STOP;
+}
+
+static int __kgdb_notify(struct die_args *args, unsigned long cmd)
+{
+	struct pt_regs *regs = args->regs;
+
+	switch (cmd) {
+	case DIE_NMI:
+		if (atomic_read(&kgdb_active) != -1) {
+			/* KGDB CPU roundup */
+			kgdb_nmicallback(raw_smp_processor_id(), regs);
+			return NOTIFY_STOP;
+		}
+		return NOTIFY_DONE;
+
+	case DIE_NMI_IPI:
+		if (atomic_read(&kgdb_active) != -1) {
+			/* KGDB CPU roundup: */
+			if (kgdb_nmicallback(raw_smp_processor_id(), regs))
+				return NOTIFY_DONE;
+			return NOTIFY_STOP;
+		}
+		return NOTIFY_DONE;
+
+	case DIE_NMIWATCHDOG:
+		if (atomic_read(&kgdb_active) != -1) {
+			/* KGDB CPU roundup: */
+			kgdb_nmicallback(raw_smp_processor_id(), regs);
+			return NOTIFY_STOP;
+		}
+		/* Enter debugger: */
+		break;
+
+	case DIE_DEBUG:
+		if (atomic_read(&kgdb_cpu_doing_single_step) ==
+			raw_smp_processor_id() &&
+			user_mode(regs))
+			return single_step_cont(regs, args);
+		/* fall through */
+	default:
+		if (user_mode(regs))
+			return NOTIFY_DONE;
+	}
+
+	if (kgdb_handle_exception(args->trapnr, args->signr, args->err, regs))
+		return NOTIFY_DONE;
+
+	return NOTIFY_STOP;
+}
+
+static int
+kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
+{
+	unsigned long flags;
+	int ret;
+
+	local_irq_save(flags);
+	ret = __kgdb_notify(ptr, cmd);
+	local_irq_restore(flags);
+
+	return ret;
+}
+
+static struct notifier_block kgdb_notifier = {
+	.notifier_call	= kgdb_notify,
+
+	/*
+	 * Lowest-prio notifier priority, we want to be notified last:
+	 */
+	.priority	= -INT_MAX,
+};
+
+/**
+ *	kgdb_arch_init - Perform any architecture specific initalization.
+ *
+ *	This function will handle the initalization of any architecture
+ *	specific callbacks.
+ */
+int kgdb_arch_init(void)
+{
+	return register_die_notifier(&kgdb_notifier);
+}
+
+/**
+ *	kgdb_arch_exit - Perform any architecture specific uninitalization.
+ *
+ *	This function will handle the uninitalization of any architecture
+ *	specific callbacks, for dynamic registration and unregistration.
+ */
+void kgdb_arch_exit(void)
+{
+	unregister_die_notifier(&kgdb_notifier);
+}
+
+/**
+ *
+ *	kgdb_skipexception - Bail of of KGDB when we've been triggered.
+ *	@exception: Exception vector number
+ *	@regs: Current &struct pt_regs.
+ *
+ *	On some architectures we need to skip a breakpoint exception when
+ *	it occurs after a breakpoint has been removed.
+ *
+ * Skip an int3 exception when it occurs after a breakpoint has been
+ * removed. Backtrack eip by 1 since the int3 would have caused it to
+ * increment by 1.
+ */
+int kgdb_skipexception(int exception, struct pt_regs *regs)
+{
+	if (exception == 3 && kgdb_isremovedbreak(regs->ip - 1)) {
+		regs->ip -= 1;
+		return 1;
+	}
+	return 0;
+}
+
+unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs)
+{
+	if (exception == 3)
+		return instruction_pointer(regs) - 1;
+	return instruction_pointer(regs);
+}
+
+struct kgdb_arch arch_kgdb_ops = {
+	/* Breakpoint instruction: */
+	.gdb_bpt_instr		= { 0xcc },
+	.flags			= KGDB_HW_BREAKPOINT,
+	.set_hw_breakpoint	= kgdb_set_hw_break,
+	.remove_hw_breakpoint	= kgdb_remove_hw_break,
+	.remove_all_hw_break	= kgdb_remove_all_hw_break,
+	.correct_hw_break	= kgdb_correct_hw_break,
+};
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 613ec81..4d3c701 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -1155,6 +1155,48 @@ static struct tty_driver *get_tty_driver(dev_t device, int *index)
 	return NULL;
 }
 
+#ifdef CONFIG_CONSOLE_POLL
+
+/**
+ *	tty_find_polling_driver	-	find device of a polled tty
+ *	@name: name string to match
+ *	@line: pointer to resulting tty line nr
+ *
+ *	This routine returns a tty driver structure, given a name
+ *	and the condition that the tty driver is capable of polled
+ *	operation.
+ */
+struct tty_driver *tty_find_polling_driver(char *name, int *line)
+{
+	struct tty_driver *p, *res = NULL;
+	int tty_line = 0;
+	char *str;
+
+	mutex_lock(&tty_mutex);
+	/* Search through the tty devices to look for a match */
+	list_for_each_entry(p, &tty_drivers, tty_drivers) {
+		str = name + strlen(p->name);
+		tty_line = simple_strtoul(str, &str, 10);
+		if (*str == ',')
+			str++;
+		if (*str == '\0')
+			str = 0;
+
+		if (tty_line >= 0 && tty_line <= p->num && p->poll_init &&
+				!p->poll_init(p, tty_line, str)) {
+
+			res = p;
+			*line = tty_line;
+			break;
+		}
+	}
+	mutex_unlock(&tty_mutex);
+
+	return res;
+}
+EXPORT_SYMBOL_GPL(tty_find_polling_driver);
+#endif
+
 /**
  *	tty_check_change	-	check for POSIX terminal changes
  *	@tty: tty to check
@@ -3850,6 +3892,11 @@ void tty_set_operations(struct tty_driver *driver,
 	driver->write_proc = op->write_proc;
 	driver->tiocmget = op->tiocmget;
 	driver->tiocmset = op->tiocmset;
+#ifdef CONFIG_CONSOLE_POLL
+	driver->poll_init = op->poll_init;
+	driver->poll_get_char = op->poll_get_char;
+	driver->poll_put_char = op->poll_put_char;
+#endif
 }
 
 
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 77f7a7f..96a585e 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -1740,6 +1740,60 @@ static inline void wait_for_xmitr(struct uart_8250_port *up, int bits)
 	}
 }
 
+#ifdef CONFIG_CONSOLE_POLL
+/*
+ * Console polling routines for writing and reading from the uart while
+ * in an interrupt or debug context.
+ */
+
+static int serial8250_get_poll_char(struct uart_port *port)
+{
+	struct uart_8250_port *up = (struct uart_8250_port *)port;
+	unsigned char lsr = serial_inp(up, UART_LSR);
+
+	while (!(lsr & UART_LSR_DR))
+		lsr = serial_inp(up, UART_LSR);
+
+	return serial_inp(up, UART_RX);
+}
+
+
+static void serial8250_put_poll_char(struct uart_port *port,
+			 unsigned char c)
+{
+	unsigned int ier;
+	struct uart_8250_port *up = (struct uart_8250_port *)port;
+
+	/*
+	 *	First save the IER then disable the interrupts
+	 */
+	ier = serial_in(up, UART_IER);
+	if (up->capabilities & UART_CAP_UUE)
+		serial_out(up, UART_IER, UART_IER_UUE);
+	else
+		serial_out(up, UART_IER, 0);
+
+	wait_for_xmitr(up, BOTH_EMPTY);
+	/*
+	 *	Send the character out.
+	 *	If a LF, also do CR...
+	 */
+	serial_out(up, UART_TX, c);
+	if (c == 10) {
+		wait_for_xmitr(up, BOTH_EMPTY);
+		serial_out(up, UART_TX, 13);
+	}
+
+	/*
+	 *	Finally, wait for transmitter to become empty
+	 *	and restore the IER
+	 */
+	wait_for_xmitr(up, BOTH_EMPTY);
+	serial_out(up, UART_IER, ier);
+}
+
+#endif /* CONFIG_CONSOLE_POLL */
+
 static int serial8250_startup(struct uart_port *port)
 {
 	struct uart_8250_port *up = (struct uart_8250_port *)port;
@@ -2386,6 +2440,10 @@ static struct uart_ops serial8250_pops = {
 	.request_port	= serial8250_request_port,
 	.config_port	= serial8250_config_port,
 	.verify_port	= serial8250_verify_port,
+#ifdef CONFIG_CONSOLE_POLL
+	.poll_get_char = serial8250_get_poll_char,
+	.poll_put_char = serial8250_put_poll_char,
+#endif
 };
 
 static struct uart_8250_port serial8250_ports[UART_NR];
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index b82595c..5d9667c 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -961,6 +961,9 @@ config SERIAL_CORE
 config SERIAL_CORE_CONSOLE
 	bool
 
+config CONSOLE_POLL
+	bool
+
 config SERIAL_68328
 	bool "68328 serial support"
 	depends on M68328 || M68EZ328 || M68VZ328
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 640cfe4..3cbea54 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -66,4 +66,5 @@ obj-$(CONFIG_SERIAL_UARTLITE) += uartlite.o
 obj-$(CONFIG_SERIAL_NETX) += netx-serial.o
 obj-$(CONFIG_SERIAL_OF_PLATFORM) += of_serial.o
 obj-$(CONFIG_SERIAL_KS8695) += serial_ks8695.o
+obj-$(CONFIG_KGDB_SERIAL_CONSOLE) += kgdboc.o
 obj-$(CONFIG_SERIAL_QE) += ucc_uart.o
diff --git a/drivers/serial/kgdboc.c b/drivers/serial/kgdboc.c
new file mode 100644
index 0000000..3418307
--- /dev/null
+++ b/drivers/serial/kgdboc.c
@@ -0,0 +1,163 @@
+/*
+ * Based on the same principle as kgdboe using the NETPOLL api, this
+ * driver uses a console polling api to implement a gdb serial inteface
+ * which is multiplexed on a console port.
+ *
+ * Maintainer: Jason Wessel <jason.wessel@windriver.com>
+ *
+ * 2007-2008 (c) Jason Wessel - Wind River Systems, Inc.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+#include <linux/kernel.h>
+#include <linux/ctype.h>
+#include <linux/kgdb.h>
+#include <linux/tty.h>
+
+#define MAX_CONFIG_LEN		40
+
+static struct kgdb_io		kgdboc_io_ops;
+
+/* -1 = init not run yet, 0 = unconfigured, 1 = configured. */
+static int configured		= -1;
+
+static char config[MAX_CONFIG_LEN];
+static struct kparam_string kps = {
+	.string			= config,
+	.maxlen			= MAX_CONFIG_LEN,
+};
+
+static struct tty_driver	*kgdb_tty_driver;
+static int			kgdb_tty_line;
+
+static int kgdboc_option_setup(char *opt)
+{
+	if (strlen(opt) > MAX_CONFIG_LEN) {
+		printk(KERN_ERR "kgdboc: config string too long\n");
+		return -ENOSPC;
+	}
+	strcpy(config, opt);
+
+	return 0;
+}
+
+__setup("kgdboc=", kgdboc_option_setup);
+
+static int configure_kgdboc(void)
+{
+	struct tty_driver *p;
+	int tty_line = 0;
+	int err;
+
+	err = kgdboc_option_setup(config);
+	if (err || !strlen(config) || isspace(config[0]))
+		goto noconfig;
+
+	err = -ENODEV;
+
+	p = tty_find_polling_driver(config, &tty_line);
+	if (!p)
+		goto noconfig;
+
+	kgdb_tty_driver = p;
+	kgdb_tty_line = tty_line;
+
+	err = kgdb_register_io_module(&kgdboc_io_ops);
+	if (err)
+		goto noconfig;
+
+	configured = 1;
+
+	return 0;
+
+noconfig:
+	config[0] = 0;
+	configured = 0;
+
+	return err;
+}
+
+static int __init init_kgdboc(void)
+{
+	/* Already configured? */
+	if (configured == 1)
+		return 0;
+
+	return configure_kgdboc();
+}
+
+static void cleanup_kgdboc(void)
+{
+	if (configured == 1)
+		kgdb_unregister_io_module(&kgdboc_io_ops);
+}
+
+static int kgdboc_get_char(void)
+{
+	return kgdb_tty_driver->poll_get_char(kgdb_tty_driver, kgdb_tty_line);
+}
+
+static void kgdboc_put_char(u8 chr)
+{
+	kgdb_tty_driver->poll_put_char(kgdb_tty_driver, kgdb_tty_line, chr);
+}
+
+static int param_set_kgdboc_var(const char *kmessage, struct kernel_param *kp)
+{
+	if (strlen(kmessage) >= MAX_CONFIG_LEN) {
+		printk(KERN_ERR "kgdboc: config string too long\n");
+		return -ENOSPC;
+	}
+
+	/* Only copy in the string if the init function has not run yet */
+	if (configured < 0) {
+		strcpy(config, kmessage);
+		return 0;
+	}
+
+	if (kgdb_connected) {
+		printk(KERN_ERR
+		       "kgdboc: Cannot reconfigure while KGDB is connected.\n");
+
+		return -EBUSY;
+	}
+
+	strcpy(config, kmessage);
+
+	if (configured == 1)
+		cleanup_kgdboc();
+
+	/* Go and configure with the new params. */
+	return configure_kgdboc();
+}
+
+static void kgdboc_pre_exp_handler(void)
+{
+	/* Increment the module count when the debugger is active */
+	if (!kgdb_connected)
+		try_module_get(THIS_MODULE);
+}
+
+static void kgdboc_post_exp_handler(void)
+{
+	/* decrement the module count when the debugger detaches */
+	if (!kgdb_connected)
+		module_put(THIS_MODULE);
+}
+
+static struct kgdb_io kgdboc_io_ops = {
+	.name			= "kgdboc",
+	.read_char		= kgdboc_get_char,
+	.write_char		= kgdboc_put_char,
+	.pre_exception		= kgdboc_pre_exp_handler,
+	.post_exception		= kgdboc_post_exp_handler,
+};
+
+module_init(init_kgdboc);
+module_exit(cleanup_kgdboc);
+module_param_call(kgdboc, param_set_kgdboc_var, param_get_string, &kps, 0644);
+MODULE_PARM_DESC(kgdboc, "<serial_device>[,baud]");
+MODULE_DESCRIPTION("KGDB Console TTY Driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index 0f5a179..cec193b 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -1827,7 +1827,7 @@ uart_get_console(struct uart_port *ports, int nr, struct console *co)
  *	options.  The format of the string is <baud><parity><bits><flow>,
  *	eg: 115200n8r
  */
-void __init
+void
 uart_parse_options(char *options, int *baud, int *parity, int *bits, int *flow)
 {
 	char *s = options;
@@ -1872,7 +1872,7 @@ static const struct baud_rates baud_rates[] = {
  *	@bits: number of data bits
  *	@flow: flow control character - 'r' (rts)
  */
-int __init
+int
 uart_set_options(struct uart_port *port, struct console *co,
 		 int baud, int parity, int bits, int flow)
 {
@@ -1924,7 +1924,12 @@ uart_set_options(struct uart_port *port, struct console *co,
 	port->mctrl |= TIOCM_DTR;
 
 	port->ops->set_termios(port, &termios, &dummy);
-	co->cflag = termios.c_cflag;
+	/*
+	 * Allow the setting of the UART parameters with a NULL console
+	 * too:
+	 */
+	if (co)
+		co->cflag = termios.c_cflag;
 
 	return 0;
 }
@@ -2182,6 +2187,60 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state,
 	}
 }
 
+#ifdef CONFIG_CONSOLE_POLL
+
+static int uart_poll_init(struct tty_driver *driver, int line, char *options)
+{
+	struct uart_driver *drv = driver->driver_state;
+	struct uart_state *state = drv->state + line;
+	struct uart_port *port;
+	int baud = 9600;
+	int bits = 8;
+	int parity = 'n';
+	int flow = 'n';
+
+	if (!state || !state->port)
+		return -1;
+
+	port = state->port;
+	if (!(port->ops->poll_get_char && port->ops->poll_put_char))
+		return -1;
+
+	if (options) {
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+		return uart_set_options(port, NULL, baud, parity, bits, flow);
+	}
+
+	return 0;
+}
+
+static int uart_poll_get_char(struct tty_driver *driver, int line)
+{
+	struct uart_driver *drv = driver->driver_state;
+	struct uart_state *state = drv->state + line;
+	struct uart_port *port;
+
+	if (!state || !state->port)
+		return -1;
+
+	port = state->port;
+	return port->ops->poll_get_char(port);
+}
+
+static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
+{
+	struct uart_driver *drv = driver->driver_state;
+	struct uart_state *state = drv->state + line;
+	struct uart_port *port;
+
+	if (!state || !state->port)
+		return;
+
+	port = state->port;
+	port->ops->poll_put_char(port, ch);
+}
+#endif
+
 static const struct tty_operations uart_ops = {
 	.open		= uart_open,
 	.close		= uart_close,
@@ -2206,6 +2265,11 @@ static const struct tty_operations uart_ops = {
 #endif
 	.tiocmget	= uart_tiocmget,
 	.tiocmset	= uart_tiocmset,
+#ifdef CONFIG_CONSOLE_POLL
+	.poll_init	= uart_poll_init,
+	.poll_get_char	= uart_poll_get_char,
+	.poll_put_char	= uart_poll_put_char,
+#endif
 };
 
 /**
diff --git a/include/asm-x86/kgdb.h b/include/asm-x86/kgdb.h
new file mode 100644
index 0000000..484c475
--- /dev/null
+++ b/include/asm-x86/kgdb.h
@@ -0,0 +1,81 @@
+#ifndef _ASM_KGDB_H_
+#define _ASM_KGDB_H_
+
+/*
+ * Copyright (C) 2001-2004 Amit S. Kale
+ * Copyright (C) 2008 Wind River Systems, Inc.
+ */
+
+/*
+ * BUFMAX defines the maximum number of characters in inbound/outbound
+ * buffers at least NUMREGBYTES*2 are needed for register packets
+ * Longer buffer is needed to list all threads
+ */
+#define BUFMAX			1024
+
+/*
+ *  Note that this register image is in a different order than
+ *  the register image that Linux produces at interrupt time.
+ *
+ *  Linux's register image is defined by struct pt_regs in ptrace.h.
+ *  Just why GDB uses a different order is a historical mystery.
+ */
+#ifdef CONFIG_X86_32
+enum regnames {
+	GDB_AX,			/* 0 */
+	GDB_CX,			/* 1 */
+	GDB_DX,			/* 2 */
+	GDB_BX,			/* 3 */
+	GDB_SP,			/* 4 */
+	GDB_BP,			/* 5 */
+	GDB_SI,			/* 6 */
+	GDB_DI,			/* 7 */
+	GDB_PC,			/* 8 also known as eip */
+	GDB_PS,			/* 9 also known as eflags */
+	GDB_CS,			/* 10 */
+	GDB_SS,			/* 11 */
+	GDB_DS,			/* 12 */
+	GDB_ES,			/* 13 */
+	GDB_FS,			/* 14 */
+	GDB_GS,			/* 15 */
+};
+#else /* ! CONFIG_X86_32 */
+enum regnames {
+	GDB_AX,			/* 0 */
+	GDB_DX,			/* 1 */
+	GDB_CX,			/* 2 */
+	GDB_BX,			/* 3 */
+	GDB_SI,			/* 4 */
+	GDB_DI,			/* 5 */
+	GDB_BP,			/* 6 */
+	GDB_SP,			/* 7 */
+	GDB_R8,			/* 8 */
+	GDB_R9,			/* 9 */
+	GDB_R10,		/* 10 */
+	GDB_R11,		/* 11 */
+	GDB_R12,		/* 12 */
+	GDB_R13,		/* 13 */
+	GDB_R14,		/* 14 */
+	GDB_R15,		/* 15 */
+	GDB_PC,			/* 16 */
+	GDB_PS,			/* 17 */
+};
+#endif /* CONFIG_X86_32 */
+
+/*
+ * Number of bytes of registers:
+ */
+#ifdef CONFIG_X86_32
+# define NUMREGBYTES		64
+#else
+# define NUMREGBYTES		((GDB_PS+1)*8)
+#endif
+
+static inline void arch_kgdb_breakpoint(void)
+{
+	asm("   int $3");
+}
+#define BREAK_INSTR_SIZE	1
+#define CACHE_FLUSH_IS_SAFE	1
+
+#endif				/* _ASM_KGDB_H_ */
diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h
new file mode 100644
index 0000000..b2be3a8
--- /dev/null
+++ b/include/linux/kgdb.h
@@ -0,0 +1,271 @@
+/*
+ * This provides the callbacks and functions that KGDB needs to share between
+ * the core, I/O and arch-specific portions.
+ *
+ * Author: Amit Kale <amitkale@linsyssoft.com> and
+ *         Tom Rini <trini@kernel.crashing.org>
+ *
+ * 2001-2004 (c) Amit S. Kale and 2003-2005 (c) MontaVista Software, Inc.
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2. This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+#ifndef _KGDB_H_
+#define _KGDB_H_
+
+#include <linux/serial_8250.h>
+#include <linux/linkage.h>
+#include <linux/init.h>
+
+#include <asm/atomic.h>
+#include <asm/kgdb.h>
+
+struct pt_regs;
+
+/*
+ *	kgdb_skipexception - Bail of of KGDB when we've been triggered.
+ *	@exception: Exception vector number
+ *	@regs: Current &struct pt_regs.
+ *
+ *	On some architectures we need to skip a breakpoint exception when
+ *	it occurs after a breakpoint has been removed.
+ */
+extern int kgdb_skipexception(int exception, struct pt_regs *regs);
+
+/*
+ *	kgdb_post_primary_code - Save error vector/code numbers.
+ *	@regs: Original pt_regs.
+ *	@e_vector: Original error vector.
+ *	@err_code: Original error code.
+ *
+ *	This is needed on architectures which support SMP and KGDB.
+ *	This function is called after all the secondary cpus have been put
+ *	to a know spin state and the primary CPU has control over KGDB.
+ */
+extern void kgdb_post_primary_code(struct pt_regs *regs, int e_vector,
+				  int err_code);
+
+/*
+ *	kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
+ *	@regs: Current &struct pt_regs.
+ *
+ *	This function will be called if the particular architecture must
+ *	disable hardware debugging while it is processing gdb packets or
+ *	handling exception.
+ */
+extern void kgdb_disable_hw_debug(struct pt_regs *regs);
+
+struct tasklet_struct;
+struct task_struct;
+struct uart_port;
+
+/* To enter the debugger explicitly. */
+void kgdb_breakpoint(void);
+
+extern int kgdb_connected;
+
+extern atomic_t			kgdb_setting_breakpoint;
+extern atomic_t			kgdb_cpu_doing_single_step;
+
+extern struct task_struct	*kgdb_usethread;
+extern struct task_struct	*kgdb_contthread;
+
+enum kgdb_bptype {
+	BP_BREAKPOINT = 0,
+	BP_HARDWARE_BREAKPOINT,
+	BP_WRITE_WATCHPOINT,
+	BP_READ_WATCHPOINT,
+	BP_ACCESS_WATCHPOINT
+};
+
+enum kgdb_bpstate {
+	BP_UNDEFINED = 0,
+	BP_REMOVED,
+	BP_SET,
+	BP_ACTIVE
+};
+
+struct kgdb_bkpt {
+	unsigned long		bpt_addr;
+	unsigned char		saved_instr[BREAK_INSTR_SIZE];
+	enum kgdb_bptype	type;
+	enum kgdb_bpstate	state;
+};
+
+#ifndef KGDB_MAX_BREAKPOINTS
+# define KGDB_MAX_BREAKPOINTS	1000
+#endif
+
+#define KGDB_HW_BREAKPOINT	1
+
+/*
+ * Functions each KGDB-supporting architecture must provide:
+ */
+
+/*
+ *	kgdb_arch_init - Perform any architecture specific initalization.
+ *
+ *	This function will handle the initalization of any architecture
+ *	specific callbacks.
+ */
+extern int kgdb_arch_init(void);
+
+/*
+ *	kgdb_arch_exit - Perform any architecture specific uninitalization.
+ *
+ *	This function will handle the uninitalization of any architecture
+ *	specific callbacks, for dynamic registration and unregistration.
+ */
+extern void kgdb_arch_exit(void);
+
+/*
+ *	pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs
+ *	@gdb_regs: A pointer to hold the registers in the order GDB wants.
+ *	@regs: The &struct pt_regs of the current process.
+ *
+ *	Convert the pt_regs in @regs into the format for registers that
+ *	GDB expects, stored in @gdb_regs.
+ */
+extern void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs);
+
+/*
+ *	sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs
+ *	@gdb_regs: A pointer to hold the registers in the order GDB wants.
+ *	@p: The &struct task_struct of the desired process.
+ *
+ *	Convert the register values of the sleeping process in @p to
+ *	the format that GDB expects.
+ *	This function is called when kgdb does not have access to the
+ *	&struct pt_regs and therefore it should fill the gdb registers
+ *	@gdb_regs with what has	been saved in &struct thread_struct
+ *	thread field during switch_to.
+ */
+extern void
+sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p);
+
+/*
+ *	gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs.
+ *	@gdb_regs: A pointer to hold the registers we've received from GDB.
+ *	@regs: A pointer to a &struct pt_regs to hold these values in.
+ *
+ *	Convert the GDB regs in @gdb_regs into the pt_regs, and store them
+ *	in @regs.
+ */
+extern void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs);
+
+/*
+ *	kgdb_arch_handle_exception - Handle architecture specific GDB packets.
+ *	@vector: The error vector of the exception that happened.
+ *	@signo: The signal number of the exception that happened.
+ *	@err_code: The error code of the exception that happened.
+ *	@remcom_in_buffer: The buffer of the packet we have read.
+ *	@remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
+ *	@regs: The &struct pt_regs of the current process.
+ *
+ *	This function MUST handle the 'c' and 's' command packets,
+ *	as well packets to set / remove a hardware breakpoint, if used.
+ *	If there are additional packets which the hardware needs to handle,
+ *	they are handled here.  The code should return -1 if it wants to
+ *	process more packets, and a %0 or %1 if it wants to exit from the
+ *	kgdb callback.
+ */
+extern int
+kgdb_arch_handle_exception(int vector, int signo, int err_code,
+			   char *remcom_in_buffer,
+			   char *remcom_out_buffer,
+			   struct pt_regs *regs);
+
+/*
+ *	kgdb_roundup_cpus - Get other CPUs into a holding pattern
+ *	@flags: Current IRQ state
+ *
+ *	On SMP systems, we need to get the attention of the other CPUs
+ *	and get them be in a known state.  This should do what is needed
+ *	to get the other CPUs to call kgdb_wait(). Note that on some arches,
+ *	the NMI approach is not used for rounding up all the CPUs. For example,
+ *	in case of MIPS, smp_call_function() is used to roundup CPUs. In
+ *	this case, we have to make sure that interrupts are enabled before
+ *	calling smp_call_function(). The argument to this function is
+ *	the flags that will be used when restoring the interrupts. There is
+ *	local_irq_save() call before kgdb_roundup_cpus().
+ *
+ *	On non-SMP systems, this is not called.
+ */
+extern void kgdb_roundup_cpus(unsigned long flags);
+
+/* Optional functions. */
+extern int kgdb_validate_break_address(unsigned long addr);
+extern int kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr);
+extern int kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle);
+
+/*
+ * struct kgdb_arch - Describe architecture specific values.
+ * @gdb_bpt_instr: The instruction to trigger a breakpoint.
+ * @flags: Flags for the breakpoint, currently just %KGDB_HW_BREAKPOINT.
+ * @set_breakpoint: Allow an architecture to specify how to set a software
+ * breakpoint.
+ * @remove_breakpoint: Allow an architecture to specify how to remove a
+ * software breakpoint.
+ * @set_hw_breakpoint: Allow an architecture to specify how to set a hardware
+ * breakpoint.
+ * @remove_hw_breakpoint: Allow an architecture to specify how to remove a
+ * hardware breakpoint.
+ * @remove_all_hw_break: Allow an architecture to specify how to remove all
+ * hardware breakpoints.
+ * @correct_hw_break: Allow an architecture to specify how to correct the
+ * hardware debug registers.
+ */
+struct kgdb_arch {
+	unsigned char		gdb_bpt_instr[BREAK_INSTR_SIZE];
+	unsigned long		flags;
+
+	int	(*set_breakpoint)(unsigned long, char *);
+	int	(*remove_breakpoint)(unsigned long, char *);
+	int	(*set_hw_breakpoint)(unsigned long, int, enum kgdb_bptype);
+	int	(*remove_hw_breakpoint)(unsigned long, int, enum kgdb_bptype);
+	void	(*remove_all_hw_break)(void);
+	void	(*correct_hw_break)(void);
+};
+
+/*
+ * struct kgdb_io - Describe the interface for an I/O driver to talk with KGDB.
+ * @name: Name of the I/O driver.
+ * @read_char: Pointer to a function that will return one char.
+ * @write_char: Pointer to a function that will write one char.
+ * @flush: Pointer to a function that will flush any pending writes.
+ * @init: Pointer to a function that will initialize the device.
+ * @pre_exception: Pointer to a function that will do any prep work for
+ * the I/O driver.
+ * @post_exception: Pointer to a function that will do any cleanup work
+ * for the I/O driver.
+ */
+struct kgdb_io {
+	const char		*name;
+	int			(*read_char) (void);
+	void			(*write_char) (u8);
+	void			(*flush) (void);
+	int			(*init) (void);
+	void			(*pre_exception) (void);
+	void			(*post_exception) (void);
+};
+
+extern struct kgdb_arch		arch_kgdb_ops;
+
+extern int kgdb_register_io_module(struct kgdb_io *local_kgdb_io_ops);
+extern void kgdb_unregister_io_module(struct kgdb_io *local_kgdb_io_ops);
+
+extern int kgdb_hex2long(char **ptr, long *long_val);
+extern int kgdb_mem2hex(char *mem, char *buf, int count);
+extern int kgdb_hex2mem(char *buf, char *mem, int count);
+
+extern int kgdb_isremovedbreak(unsigned long addr);
+
+extern int
+kgdb_handle_exception(int ex_vector, int signo, int err_code,
+		      struct pt_regs *regs);
+extern int kgdb_nmicallback(int cpu, void *regs);
+
+extern int			kgdb_single_step;
+extern atomic_t			kgdb_active;
+
+#endif /* _KGDB_H_ */
diff --git a/include/linux/pid.h b/include/linux/pid.h
index f84d532..e066d3d 100644
--- a/include/linux/pid.h
+++ b/include/linux/pid.h
@@ -86,6 +86,8 @@ extern struct task_struct *FASTCALL(get_pid_task(struct pid *pid,
 
 extern struct pid *get_task_pid(struct task_struct *task, enum pid_type type);
 
+extern int pid_max;
+
 /*
  * attach_pid() and detach_pid() must be called with the tasklist_lock
  * write-held.
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 1a0b6cf..7d1a46b 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -211,6 +211,10 @@ struct uart_ops {
 	void		(*config_port)(struct uart_port *, int);
 	int		(*verify_port)(struct uart_port *, struct serial_struct *);
 	int		(*ioctl)(struct uart_port *, unsigned int, unsigned long);
+#ifdef CONFIG_CONSOLE_POLL
+	void	(*poll_put_char)(struct uart_port *, unsigned char);
+	int		(*poll_get_char)(struct uart_port *);
+#endif
 };
 
 #define UART_CONFIG_TYPE	(1 << 0)
diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index 85c95cd..21f69ac 100644
--- a/include/linux/tty_driver.h
+++ b/include/linux/tty_driver.h
@@ -125,6 +125,7 @@
 #include <linux/cdev.h>
 
 struct tty_struct;
+struct tty_driver;
 
 struct tty_operations {
 	int  (*open)(struct tty_struct * tty, struct file * filp);
@@ -157,6 +158,11 @@ struct tty_operations {
 	int (*tiocmget)(struct tty_struct *tty, struct file *file);
 	int (*tiocmset)(struct tty_struct *tty, struct file *file,
 			unsigned int set, unsigned int clear);
+#ifdef CONFIG_CONSOLE_POLL
+	int (*poll_init)(struct tty_driver *driver, int line, char *options);
+	int (*poll_get_char)(struct tty_driver *driver, int line);
+	void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
+#endif
 };
 
 struct tty_driver {
@@ -220,6 +226,11 @@ struct tty_driver {
 	int (*tiocmget)(struct tty_struct *tty, struct file *file);
 	int (*tiocmset)(struct tty_struct *tty, struct file *file,
 			unsigned int set, unsigned int clear);
+#ifdef CONFIG_CONSOLE_POLL
+	int (*poll_init)(struct tty_driver *driver, int line, char *options);
+	int (*poll_get_char)(struct tty_driver *driver, int line);
+	void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
+#endif
 
 	struct list_head tty_drivers;
 };
@@ -230,6 +241,7 @@ struct tty_driver *alloc_tty_driver(int lines);
 void put_tty_driver(struct tty_driver *driver);
 void tty_set_operations(struct tty_driver *driver,
 			const struct tty_operations *op);
+extern struct tty_driver *tty_find_polling_driver(char *name, int *line);
 
 /* tty driver magic number */
 #define TTY_DRIVER_MAGIC		0x5402
diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index 975c963..fec6dec 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -84,4 +84,26 @@ static inline unsigned long __copy_from_user_nocache(void *to,
 		ret;					\
 	})
 
+/*
+ * probe_kernel_read(): safely attempt to read from a location
+ * @dst: pointer to the buffer that shall take the data
+ * @src: address to read from
+ * @size: size of the data chunk
+ *
+ * Safely read from address @src to the buffer at @dst.  If a kernel fault
+ * happens, handle that and return -EFAULT.
+ */
+extern long probe_kernel_read(void *dst, void *src, size_t size);
+
+/*
+ * probe_kernel_write(): safely attempt to write to a location
+ * @dst: address to write to
+ * @src: pointer to the data that shall be written
+ * @size: size of the data chunk
+ *
+ * Safely write to address @dst from the buffer at @src.  If a kernel fault
+ * happens, handle that and return -EFAULT.
+ */
+extern long probe_kernel_write(void *dst, void *src, size_t size);
+
 #endif		/* __LINUX_UACCESS_H__ */
diff --git a/kernel/Makefile b/kernel/Makefile
index 6c584c5..05c8003 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -53,6 +53,7 @@ obj-$(CONFIG_AUDIT) += audit.o auditfilter.o
 obj-$(CONFIG_AUDITSYSCALL) += auditsc.o
 obj-$(CONFIG_AUDIT_TREE) += audit_tree.o
 obj-$(CONFIG_KPROBES) += kprobes.o
+obj-$(CONFIG_KGDB) += kgdb.o
 obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
 obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
 obj-$(CONFIG_SECCOMP) += seccomp.o
diff --git a/kernel/kgdb.c b/kernel/kgdb.c
new file mode 100644
index 0000000..2bfdd48
--- /dev/null
+++ b/kernel/kgdb.c
@@ -0,0 +1,1663 @@
+/*
+ * KGDB stub.
+ *
+ * Maintainer: Jason Wessel <jason.wessel@windriver.com>
+ *
+ * Copyright (C) 2000-2001 VERITAS Software Corporation.
+ * Copyright (C) 2002-2004 Timesys Corporation
+ * Copyright (C) 2003-2004 Amit S. Kale <amitkale@linsyssoft.com>
+ * Copyright (C) 2004 Pavel Machek <pavel@suse.cz>
+ * Copyright (C) 2004-2006 Tom Rini <trini@kernel.crashing.org>
+ * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd.
+ * Copyright (C) 2005-2008 Wind River Systems, Inc.
+ * Copyright (C) 2007 MontaVista Software, Inc.
+ * Copyright (C) 2008 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ * Contributors at various stages not listed above:
+ *  Jason Wessel ( jason.wessel@windriver.com )
+ *  George Anzinger <george@mvista.com>
+ *  Anurekh Saxena (anurekh.saxena@timesys.com)
+ *  Lake Stevens Instrument Division (Glenn Engel)
+ *  Jim Kingdon, Cygnus Support.
+ *
+ * Original KGDB stub: David Grothe <dave@gcom.com>,
+ * Tigran Aivazian <tigran@sco.com>
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2. This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+#include <linux/pid_namespace.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/console.h>
+#include <linux/threads.h>
+#include <linux/uaccess.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/ptrace.h>
+#include <linux/reboot.h>
+#include <linux/string.h>
+#include <linux/delay.h>
+#include <linux/sched.h>
+#include <linux/sysrq.h>
+#include <linux/init.h>
+#include <linux/kgdb.h>
+#include <linux/pid.h>
+#include <linux/smp.h>
+#include <linux/mm.h>
+
+#include <asm/cacheflush.h>
+#include <asm/byteorder.h>
+#include <asm/atomic.h>
+#include <asm/system.h>
+
+static int kgdb_break_asap;
+
+struct kgdb_state {
+	int			ex_vector;
+	int			signo;
+	int			err_code;
+	int			cpu;
+	int			pass_exception;
+	long			threadid;
+	long			kgdb_usethreadid;
+	struct pt_regs		*linux_regs;
+};
+
+static struct debuggerinfo_struct {
+	void			*debuggerinfo;
+	struct task_struct	*task;
+} kgdb_info[NR_CPUS];
+
+/**
+ * kgdb_connected - Is a host GDB connected to us?
+ */
+int				kgdb_connected;
+EXPORT_SYMBOL_GPL(kgdb_connected);
+
+/* All the KGDB handlers are installed */
+static int			kgdb_io_module_registered;
+
+/* Guard for recursive entry */
+static int			exception_level;
+
+static struct kgdb_io		*kgdb_io_ops;
+static DEFINE_SPINLOCK(kgdb_registration_lock);
+
+/* kgdb console driver is loaded */
+static int kgdb_con_registered;
+/* determine if kgdb console output should be used */
+static int kgdb_use_con;
+
+static int __init opt_kgdb_con(char *str)
+{
+	kgdb_use_con = 1;
+	return 0;
+}
+
+early_param("kgdbcon", opt_kgdb_con);
+
+module_param(kgdb_use_con, int, 0644);
+
+/*
+ * Holds information about breakpoints in a kernel. These breakpoints are
+ * added and removed by gdb.
+ */
+static struct kgdb_bkpt		kgdb_break[KGDB_MAX_BREAKPOINTS] = {
+	[0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED }
+};
+
+/*
+ * The CPU# of the active CPU, or -1 if none:
+ */
+atomic_t			kgdb_active = ATOMIC_INIT(-1);
+
+/*
+ * We use NR_CPUs not PERCPU, in case kgdb is used to debug early
+ * bootup code (which might not have percpu set up yet):
+ */
+static atomic_t			passive_cpu_wait[NR_CPUS];
+static atomic_t			cpu_in_kgdb[NR_CPUS];
+atomic_t			kgdb_setting_breakpoint;
+
+struct task_struct		*kgdb_usethread;
+struct task_struct		*kgdb_contthread;
+
+int				kgdb_single_step;
+
+/* Our I/O buffers. */
+static char			remcom_in_buffer[BUFMAX];
+static char			remcom_out_buffer[BUFMAX];
+
+/* Storage for the registers, in GDB format. */
+static unsigned long		gdb_regs[(NUMREGBYTES +
+					sizeof(unsigned long) - 1) /
+					sizeof(unsigned long)];
+
+/* to keep track of the CPU which is doing the single stepping*/
+atomic_t			kgdb_cpu_doing_single_step = ATOMIC_INIT(-1);
+
+/*
+ * Finally, some KGDB code :-)
+ */
+
+/*
+ * Weak aliases for breakpoint management,
+ * can be overriden by architectures when needed:
+ */
+int __weak kgdb_validate_break_address(unsigned long addr)
+{
+	char tmp_variable[BREAK_INSTR_SIZE];
+
+	return probe_kernel_read(tmp_variable, (char *)addr, BREAK_INSTR_SIZE);
+}
+
+int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr)
+{
+	int err;
+
+	err = probe_kernel_read(saved_instr, (char *)addr, BREAK_INSTR_SIZE);
+	if (err)
+		return err;
+
+	return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr,
+				  BREAK_INSTR_SIZE);
+}
+
+int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle)
+{
+	return probe_kernel_write((char *)addr,
+				  (char *)bundle, BREAK_INSTR_SIZE);
+}
+
+unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs)
+{
+	return instruction_pointer(regs);
+}
+
+int __weak kgdb_arch_init(void)
+{
+	return 0;
+}
+
+/*
+ * GDB remote protocol parser:
+ */
+
+static const char	hexchars[] = "0123456789abcdef";
+
+static int hex(char ch)
+{
+	if ((ch >= 'a') && (ch <= 'f'))
+		return ch - 'a' + 10;
+	if ((ch >= '0') && (ch <= '9'))
+		return ch - '0';
+	if ((ch >= 'A') && (ch <= 'F'))
+		return ch - 'A' + 10;
+	return -1;
+}
+
+/* scan for the sequence $<data>#<checksum> */
+static void get_packet(char *buffer)
+{
+	unsigned char checksum;
+	unsigned char xmitcsum;
+	int count;
+	char ch;
+
+	do {
+		/*
+		 * Spin and wait around for the start character, ignore all
+		 * other characters:
+		 */
+		while ((ch = (kgdb_io_ops->read_char())) != '$')
+			/* nothing */;
+
+		kgdb_connected = 1;
+		checksum = 0;
+		xmitcsum = -1;
+
+		count = 0;
+
+		/*
+		 * now, read until a # or end of buffer is found:
+		 */
+		while (count < (BUFMAX - 1)) {
+			ch = kgdb_io_ops->read_char();
+			if (ch == '#')
+				break;
+			checksum = checksum + ch;
+			buffer[count] = ch;
+			count = count + 1;
+		}
+		buffer[count] = 0;
+
+		if (ch == '#') {
+			xmitcsum = hex(kgdb_io_ops->read_char()) << 4;
+			xmitcsum += hex(kgdb_io_ops->read_char());
+
+			if (checksum != xmitcsum)
+				/* failed checksum */
+				kgdb_io_ops->write_char('-');
+			else
+				/* successful transfer */
+				kgdb_io_ops->write_char('+');
+			if (kgdb_io_ops->flush)
+				kgdb_io_ops->flush();
+		}
+	} while (checksum != xmitcsum);
+}
+
+/*
+ * Send the packet in buffer.
+ * Check for gdb connection if asked for.
+ */
+static void put_packet(char *buffer)
+{
+	unsigned char checksum;
+	int count;
+	char ch;
+
+	/*
+	 * $<packet info>#<checksum>.
+	 */
+	while (1) {
+		kgdb_io_ops->write_char('$');
+		checksum = 0;
+		count = 0;
+
+		while ((ch = buffer[count])) {
+			kgdb_io_ops->write_char(ch);
+			checksum += ch;
+			count++;
+		}
+
+		kgdb_io_ops->write_char('#');
+		kgdb_io_ops->write_char(hexchars[checksum >> 4]);
+		kgdb_io_ops->write_char(hexchars[checksum & 0xf]);
+		if (kgdb_io_ops->flush)
+			kgdb_io_ops->flush();
+
+		/* Now see what we get in reply. */
+		ch = kgdb_io_ops->read_char();
+
+		if (ch == 3)
+			ch = kgdb_io_ops->read_char();
+
+		/* If we get an ACK, we are done. */
+		if (ch == '+')
+			return;
+
+		/*
+		 * If we get the start of another packet, this means
+		 * that GDB is attempting to reconnect.  We will NAK
+		 * the packet being sent, and stop trying to send this
+		 * packet.
+		 */
+		if (ch == '$') {
+			kgdb_io_ops->write_char('-');
+			if (kgdb_io_ops->flush)
+				kgdb_io_ops->flush();
+			return;
+		}
+	}
+}
+
+static char *pack_hex_byte(char *pkt, u8 byte)
+{
+	*pkt++ = hexchars[byte >> 4];
+	*pkt++ = hexchars[byte & 0xf];
+
+	return pkt;
+}
+
+/*
+ * Convert the memory pointed to by mem into hex, placing result in buf.
+ * Return a pointer to the last char put in buf (null). May return an error.
+ */
+int kgdb_mem2hex(char *mem, char *buf, int count)
+{
+	char *tmp;
+	int err;
+
+	/*
+	 * We use the upper half of buf as an intermediate buffer for the
+	 * raw memory copy.  Hex conversion will work against this one.
+	 */
+	tmp = buf + count;
+
+	err = probe_kernel_read(tmp, mem, count);
+	if (!err) {
+		while (count > 0) {
+			buf = pack_hex_byte(buf, *tmp);
+			tmp++;
+			count--;
+		}
+
+		*buf = 0;
+	}
+
+	return err;
+}
+
+/*
+ * Copy the binary array pointed to by buf into mem.  Fix $, #, and
+ * 0x7d escaped with 0x7d.  Return a pointer to the character after
+ * the last byte written.
+ */
+static int kgdb_ebin2mem(char *buf, char *mem, int count)
+{
+	int err = 0;
+	char c;
+
+	while (count-- > 0) {
+		c = *buf++;
+		if (c == 0x7d)
+			c = *buf++ ^ 0x20;
+
+		err = probe_kernel_write(mem, &c, 1);
+		if (err)
+			break;
+
+		mem++;
+	}
+
+	return err;
+}
+
+/*
+ * Convert the hex array pointed to by buf into binary to be placed in mem.
+ * Return a pointer to the character AFTER the last byte written.
+ * May return an error.
+ */
+int kgdb_hex2mem(char *buf, char *mem, int count)
+{
+	char *tmp_raw;
+	char *tmp_hex;
+
+	/*
+	 * We use the upper half of buf as an intermediate buffer for the
+	 * raw memory that is converted from hex.
+	 */
+	tmp_raw = buf + count * 2;
+
+	tmp_hex = tmp_raw - 1;
+	while (tmp_hex >= buf) {
+		tmp_raw--;
+		*tmp_raw = hex(*tmp_hex--);
+		*tmp_raw |= hex(*tmp_hex--) << 4;
+	}
+
+	return probe_kernel_write(mem, tmp_raw, count);
+}
+
+/*
+ * While we find nice hex chars, build a long_val.
+ * Return number of chars processed.
+ */
+int kgdb_hex2long(char **ptr, long *long_val)
+{
+	int hex_val;
+	int num = 0;
+
+	*long_val = 0;
+
+	while (**ptr) {
+		hex_val = hex(**ptr);
+		if (hex_val < 0)
+			break;
+
+		*long_val = (*long_val << 4) | hex_val;
+		num++;
+		(*ptr)++;
+	}
+
+	return num;
+}
+
+/* Write memory due to an 'M' or 'X' packet. */
+static int write_mem_msg(int binary)
+{
+	char *ptr = &remcom_in_buffer[1];
+	unsigned long addr;
+	unsigned long length;
+	int err;
+
+	if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' &&
+	    kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') {
+		if (binary)
+			err = kgdb_ebin2mem(ptr, (char *)addr, length);
+		else
+			err = kgdb_hex2mem(ptr, (char *)addr, length);
+		if (err)
+			return err;
+		if (CACHE_FLUSH_IS_SAFE)
+			flush_icache_range(addr, addr + length + 1);
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static void error_packet(char *pkt, int error)
+{
+	error = -error;
+	pkt[0] = 'E';
+	pkt[1] = hexchars[(error / 10)];
+	pkt[2] = hexchars[(error % 10)];
+	pkt[3] = '\0';
+}
+
+/*
+ * Black magic portion #2. Thread ID accessors.
+ */
+
+#define BUF_THREAD_ID_SIZE	16
+
+static char *pack_threadid(char *pkt, unsigned char *id)
+{
+	char *limit;
+
+	limit = pkt + BUF_THREAD_ID_SIZE;
+	while (pkt < limit)
+		pkt = pack_hex_byte(pkt, *id++);
+
+	return pkt;
+}
+
+static void int_to_threadref(unsigned char *id, int value)
+{
+	unsigned char *scan;
+	int i = 4;
+
+	scan = (unsigned char *)id;
+	while (i--)
+		*scan++ = 0;
+	*scan++ = (value >> 24) & 0xff;
+	*scan++ = (value >> 16) & 0xff;
+	*scan++ = (value >> 8) & 0xff;
+	*scan++ = (value & 0xff);
+}
+
+static struct task_struct *getthread(struct pt_regs *regs, int tid)
+{
+	if (num_online_cpus() && (tid >= pid_max + num_online_cpus()))
+		return NULL;
+
+	if (tid >= pid_max)
+		return idle_task(tid - pid_max);
+
+	if (!tid)
+		return NULL;
+
+	/*
+	 * find_task_by_pid() does not take the tasklist lock anymore
+	 * but is nicely RCU locked - hence is a pretty resilient
+	 * thing to use:
+	 */
+	return find_task_by_pid(tid);
+}
+
+/*
+ * CPU debug state control:
+ */
+
+#ifdef CONFIG_SMP
+static void kgdb_wait(struct pt_regs *regs)
+{
+	unsigned long flags;
+	int cpu;
+
+	local_irq_save(flags);
+	cpu = raw_smp_processor_id();
+	kgdb_info[cpu].debuggerinfo = regs;
+	kgdb_info[cpu].task = current;
+	/*
+	 * Make sure the above info reaches the primary CPU before
+	 * our cpu_in_kgdb[] flag setting does:
+	 */
+	smp_wmb();
+	atomic_set(&cpu_in_kgdb[cpu], 1);
+
+	/*
+	 * The primary CPU must be active to enter here, but this is
+	 * guard in case the primary CPU had not been selected if
+	 * this was an entry via nmi.
+	 */
+	while (atomic_read(&kgdb_active) == -1)
+		cpu_relax();
+
+	/* Wait till primary CPU goes completely into the debugger. */
+	while (!atomic_read(&cpu_in_kgdb[atomic_read(&kgdb_active)]))
+		cpu_relax();
+
+	/* Wait till primary CPU is done with debugging */
+	while (atomic_read(&passive_cpu_wait[cpu]))
+		cpu_relax();
+
+	kgdb_info[cpu].debuggerinfo = NULL;
+	kgdb_info[cpu].task = NULL;
+
+	/* fix up hardware debug registers on local cpu */
+	if (arch_kgdb_ops.correct_hw_break)
+		arch_kgdb_ops.correct_hw_break();
+
+	/* Signal the primary CPU that we are done: */
+	atomic_set(&cpu_in_kgdb[cpu], 0);
+	local_irq_restore(flags);
+}
+#endif
+
+/*
+ * Some architectures need cache flushes when we set/clear a
+ * breakpoint:
+ */
+static void kgdb_flush_swbreak_addr(unsigned long addr)
+{
+	if (!CACHE_FLUSH_IS_SAFE)
+		return;
+
+	if (current->mm) {
+		flush_cache_range(current->mm->mmap_cache,
+				  addr, addr + BREAK_INSTR_SIZE);
+	} else {
+		flush_icache_range(addr, addr + BREAK_INSTR_SIZE);
+	}
+}
+
+/*
+ * SW breakpoint management:
+ */
+static int kgdb_activate_sw_breakpoints(void)
+{
+	unsigned long addr;
+	int error = 0;
+	int i;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (kgdb_break[i].state != BP_SET)
+			continue;
+
+		addr = kgdb_break[i].bpt_addr;
+		error = kgdb_arch_set_breakpoint(addr,
+				kgdb_break[i].saved_instr);
+		if (error)
+			return error;
+
+		kgdb_flush_swbreak_addr(addr);
+		kgdb_break[i].state = BP_ACTIVE;
+	}
+	return 0;
+}
+
+static int kgdb_set_sw_break(unsigned long addr)
+{
+	int err = kgdb_validate_break_address(addr);
+	int breakno = -1;
+	int i;
+
+	if (err)
+		return err;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if ((kgdb_break[i].state == BP_SET) &&
+					(kgdb_break[i].bpt_addr == addr))
+			return -EEXIST;
+	}
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (kgdb_break[i].state == BP_REMOVED &&
+					kgdb_break[i].bpt_addr == addr) {
+			breakno = i;
+			break;
+		}
+	}
+
+	if (breakno == -1) {
+		for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+			if (kgdb_break[i].state == BP_UNDEFINED) {
+				breakno = i;
+				break;
+			}
+		}
+	}
+
+	if (breakno == -1)
+		return -E2BIG;
+
+	kgdb_break[breakno].state = BP_SET;
+	kgdb_break[breakno].type = BP_BREAKPOINT;
+	kgdb_break[breakno].bpt_addr = addr;
+
+	return 0;
+}
+
+static int kgdb_deactivate_sw_breakpoints(void)
+{
+	unsigned long addr;
+	int error = 0;
+	int i;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (kgdb_break[i].state != BP_ACTIVE)
+			continue;
+		addr = kgdb_break[i].bpt_addr;
+		error = kgdb_arch_remove_breakpoint(addr,
+					kgdb_break[i].saved_instr);
+		if (error)
+			return error;
+
+		kgdb_flush_swbreak_addr(addr);
+		kgdb_break[i].state = BP_SET;
+	}
+	return 0;
+}
+
+static int kgdb_remove_sw_break(unsigned long addr)
+{
+	int i;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if ((kgdb_break[i].state == BP_SET) &&
+				(kgdb_break[i].bpt_addr == addr)) {
+			kgdb_break[i].state = BP_REMOVED;
+			return 0;
+		}
+	}
+	return -ENOENT;
+}
+
+int kgdb_isremovedbreak(unsigned long addr)
+{
+	int i;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if ((kgdb_break[i].state == BP_REMOVED) &&
+					(kgdb_break[i].bpt_addr == addr))
+			return 1;
+	}
+	return 0;
+}
+
+int remove_all_break(void)
+{
+	unsigned long addr;
+	int error;
+	int i;
+
+	/* Clear memory breakpoints. */
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (kgdb_break[i].state != BP_SET)
+			continue;
+		addr = kgdb_break[i].bpt_addr;
+		error = kgdb_arch_remove_breakpoint(addr,
+				kgdb_break[i].saved_instr);
+		if (error)
+			return error;
+		kgdb_break[i].state = BP_REMOVED;
+	}
+
+	/* Clear hardware breakpoints. */
+	if (arch_kgdb_ops.remove_all_hw_break)
+		arch_kgdb_ops.remove_all_hw_break();
+
+	return 0;
+}
+
+static inline int shadow_pid(int realpid)
+{
+	if (realpid)
+		return realpid;
+
+	return pid_max + raw_smp_processor_id();
+}
+
+static char gdbmsgbuf[BUFMAX + 1];
+
+static void kgdb_msg_write(const char *s, int len)
+{
+	char *bufptr;
+	int wcount;
+	int i;
+
+	/* 'O'utput */
+	gdbmsgbuf[0] = 'O';
+
+	/* Fill and send buffers... */
+	while (len > 0) {
+		bufptr = gdbmsgbuf + 1;
+
+		/* Calculate how many this time */
+		if ((len << 1) > (BUFMAX - 2))
+			wcount = (BUFMAX - 2) >> 1;
+		else
+			wcount = len;
+
+		/* Pack in hex chars */
+		for (i = 0; i < wcount; i++)
+			bufptr = pack_hex_byte(bufptr, s[i]);
+		*bufptr = '\0';
+
+		/* Move up */
+		s += wcount;
+		len -= wcount;
+
+		/* Write packet */
+		put_packet(gdbmsgbuf);
+	}
+}
+
+/*
+ * Return true if there is a valid kgdb I/O module.  Also if no
+ * debugger is attached a message can be printed to the console about
+ * waiting for the debugger to attach.
+ *
+ * The print_wait argument is only to be true when called from inside
+ * the core kgdb_handle_exception, because it will wait for the
+ * debugger to attach.
+ */
+static int kgdb_io_ready(int print_wait)
+{
+	if (!kgdb_io_ops)
+		return 0;
+	if (kgdb_connected)
+		return 1;
+	if (atomic_read(&kgdb_setting_breakpoint))
+		return 1;
+	if (print_wait)
+		printk(KERN_CRIT "KGDB: Waiting for remote debugger\n");
+	return 1;
+}
+
+/*
+ * All the functions that start with gdb_cmd are the various
+ * operations to implement the handlers for the gdbserial protocol
+ * where KGDB is communicating with an external debugger
+ */
+
+/* Handle the '?' status packets */
+static void gdb_cmd_status(struct kgdb_state *ks)
+{
+	/*
+	 * We know that this packet is only sent
+	 * during initial connect.  So to be safe,
+	 * we clear out our breakpoints now in case
+	 * GDB is reconnecting.
+	 */
+	remove_all_break();
+
+	remcom_out_buffer[0] = 'S';
+	pack_hex_byte(&remcom_out_buffer[1], ks->signo);
+}
+
+/* Handle the 'g' get registers request */
+static void gdb_cmd_getregs(struct kgdb_state *ks)
+{
+	struct task_struct *thread;
+	void *local_debuggerinfo;
+	int i;
+
+	thread = kgdb_usethread;
+	if (!thread) {
+		thread = kgdb_info[ks->cpu].task;
+		local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo;
+	} else {
+		local_debuggerinfo = NULL;
+		for (i = 0; i < NR_CPUS; i++) {
+			/*
+			 * Try to find the task on some other
+			 * or possibly this node if we do not
+			 * find the matching task then we try
+			 * to approximate the results.
+			 */
+			if (thread == kgdb_info[i].task)
+				local_debuggerinfo = kgdb_info[i].debuggerinfo;
+		}
+	}
+
+	/*
+	 * All threads that don't have debuggerinfo should be
+	 * in __schedule() sleeping, since all other CPUs
+	 * are in kgdb_wait, and thus have debuggerinfo.
+	 */
+	if (local_debuggerinfo) {
+		pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo);
+	} else {
+		/*
+		 * Pull stuff saved during switch_to; nothing
+		 * else is accessible (or even particularly
+		 * relevant).
+		 *
+		 * This should be enough for a stack trace.
+		 */
+		sleeping_thread_to_gdb_regs(gdb_regs, thread);
+	}
+	kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES);
+}
+
+/* Handle the 'G' set registers request */
+static void gdb_cmd_setregs(struct kgdb_state *ks)
+{
+	kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES);
+
+	if (kgdb_usethread && kgdb_usethread != current) {
+		error_packet(remcom_out_buffer, -EINVAL);
+	} else {
+		gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs);
+		strcpy(remcom_out_buffer, "OK");
+	}
+}
+
+/* Handle the 'm' memory read bytes */
+static void gdb_cmd_memread(struct kgdb_state *ks)
+{
+	char *ptr = &remcom_in_buffer[1];
+	unsigned long length;
+	unsigned long addr;
+	int err;
+
+	if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' &&
+					kgdb_hex2long(&ptr, &length) > 0) {
+		err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length);
+		if (err)
+			error_packet(remcom_out_buffer, err);
+	} else {
+		error_packet(remcom_out_buffer, -EINVAL);
+	}
+}
+
+/* Handle the 'M' memory write bytes */
+static void gdb_cmd_memwrite(struct kgdb_state *ks)
+{
+	int err = write_mem_msg(0);
+
+	if (err)
+		error_packet(remcom_out_buffer, err);
+	else
+		strcpy(remcom_out_buffer, "OK");
+}
+
+/* Handle the 'X' memory binary write bytes */
+static void gdb_cmd_binwrite(struct kgdb_state *ks)
+{
+	int err = write_mem_msg(1);
+
+	if (err)
+		error_packet(remcom_out_buffer, err);
+	else
+		strcpy(remcom_out_buffer, "OK");
+}
+
+/* Handle the 'D' or 'k', detach or kill packets */
+static void gdb_cmd_detachkill(struct kgdb_state *ks)
+{
+	int error;
+
+	/* The detach case */
+	if (remcom_in_buffer[0] == 'D') {
+		error = remove_all_break();
+		if (error < 0) {
+			error_packet(remcom_out_buffer, error);
+		} else {
+			strcpy(remcom_out_buffer, "OK");
+			kgdb_connected = 0;
+		}
+		put_packet(remcom_out_buffer);
+	} else {
+		/*
+		 * Assume the kill case, with no exit code checking,
+		 * trying to force detach the debugger:
+		 */
+		remove_all_break();
+		kgdb_connected = 0;
+	}
+}
+
+/* Handle the 'R' reboot packets */
+static int gdb_cmd_reboot(struct kgdb_state *ks)
+{
+	/* For now, only honor R0 */
+	if (strcmp(remcom_in_buffer, "R0") == 0) {
+		printk(KERN_CRIT "Executing reboot\n");
+		strcpy(remcom_out_buffer, "OK");
+		put_packet(remcom_out_buffer);
+
+		/*
+		 * Execution should not return from
+		 * machine_restart()
+		 */
+		machine_restart(NULL);
+		kgdb_connected = 0;
+
+		return 1;
+	}
+	return 0;
+}
+
+/* Handle the 'q' query packets */
+static void gdb_cmd_query(struct kgdb_state *ks)
+{
+	int numshadowth = num_online_cpus();
+	struct task_struct *thread;
+	unsigned char thref[8];
+	char *ptr;
+	int i;
+
+	switch (remcom_in_buffer[1]) {
+	case 's':
+	case 'f':
+		if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) {
+			error_packet(remcom_out_buffer, -EINVAL);
+			break;
+		}
+
+		if (remcom_in_buffer[1] == 'f')
+			ks->threadid = 1;
+
+		remcom_out_buffer[0] = 'm';
+		ptr = remcom_out_buffer + 1;
+
+		for (i = 0; i < 17 && ks->threadid < pid_max + numshadowth;
+							ks->threadid++) {
+
+			thread = getthread(ks->linux_regs, ks->threadid);
+			if (thread) {
+				int_to_threadref(thref, ks->threadid);
+				pack_threadid(ptr, thref);
+				ptr += 16;
+				*(ptr++) = ',';
+				i++;
+			}
+		}
+		*(--ptr) = '\0';
+		break;
+
+	case 'C':
+		/* Current thread id */
+		strcpy(remcom_out_buffer, "QC");
+		ks->threadid = shadow_pid(current->pid);
+		int_to_threadref(thref, ks->threadid);
+		pack_threadid(remcom_out_buffer + 2, thref);
+		break;
+	case 'T':
+		if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) {
+			error_packet(remcom_out_buffer, -EINVAL);
+			break;
+		}
+		ks->threadid = 0;
+		ptr = remcom_in_buffer + 17;
+		kgdb_hex2long(&ptr, &ks->threadid);
+		if (!getthread(ks->linux_regs, ks->threadid)) {
+			error_packet(remcom_out_buffer, -EINVAL);
+			break;
+		}
+		if (ks->threadid < pid_max) {
+			kgdb_mem2hex(getthread(ks->linux_regs,
+					ks->threadid)->comm,
+					remcom_out_buffer, 16);
+		} else {
+			static char tmpstr[23 + BUF_THREAD_ID_SIZE];
+			sprintf(tmpstr, "Shadow task %d for pid 0",
+					(int)(ks->threadid - pid_max));
+			kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr));
+		}
+		break;
+	}
+}
+
+/* Handle the 'H' task query packets */
+static void gdb_cmd_task(struct kgdb_state *ks)
+{
+	struct task_struct *thread;
+	char *ptr;
+
+	switch (remcom_in_buffer[1]) {
+	case 'g':
+		ptr = &remcom_in_buffer[2];
+		kgdb_hex2long(&ptr, &ks->threadid);
+		thread = getthread(ks->linux_regs, ks->threadid);
+		if (!thread && ks->threadid > 0) {
+			error_packet(remcom_out_buffer, -EINVAL);
+			break;
+		}
+		kgdb_usethread = thread;
+		ks->kgdb_usethreadid = ks->threadid;
+		strcpy(remcom_out_buffer, "OK");
+		break;
+	case 'c':
+		ptr = &remcom_in_buffer[2];
+		kgdb_hex2long(&ptr, &ks->threadid);
+		if (!ks->threadid) {
+			kgdb_contthread = NULL;
+		} else {
+			thread = getthread(ks->linux_regs, ks->threadid);
+			if (!thread && ks->threadid > 0) {
+				error_packet(remcom_out_buffer, -EINVAL);
+				break;
+			}
+			kgdb_contthread = thread;
+		}
+		strcpy(remcom_out_buffer, "OK");
+		break;
+	}
+}
+
+/* Handle the 'T' thread query packets */
+static void gdb_cmd_thread(struct kgdb_state *ks)
+{
+	char *ptr = &remcom_in_buffer[1];
+	struct task_struct *thread;
+
+	kgdb_hex2long(&ptr, &ks->threadid);
+	thread = getthread(ks->linux_regs, ks->threadid);
+	if (thread)
+		strcpy(remcom_out_buffer, "OK");
+	else
+		error_packet(remcom_out_buffer, -EINVAL);
+}
+
+/* Handle the 'z' or 'Z' breakpoint remove or set packets */
+static void gdb_cmd_break(struct kgdb_state *ks)
+{
+	/*
+	 * Since GDB-5.3, it's been drafted that '0' is a software
+	 * breakpoint, '1' is a hardware breakpoint, so let's do that.
+	 */
+	char *bpt_type = &remcom_in_buffer[1];
+	char *ptr = &remcom_in_buffer[2];
+	unsigned long addr;
+	unsigned long length;
+	int error = 0;
+
+	if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') {
+		/* Unsupported */
+		if (*bpt_type > '4')
+			return;
+	} else {
+		if (*bpt_type != '0' && *bpt_type != '1')
+			/* Unsupported. */
+			return;
+	}
+
+	/*
+	 * Test if this is a hardware breakpoint, and
+	 * if we support it:
+	 */
+	if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT))
+		/* Unsupported. */
+		return;
+
+	if (*(ptr++) != ',') {
+		error_packet(remcom_out_buffer, -EINVAL);
+		return;
+	}
+	if (!kgdb_hex2long(&ptr, &addr)) {
+		error_packet(remcom_out_buffer, -EINVAL);
+		return;
+	}
+	if (*(ptr++) != ',' ||
+		!kgdb_hex2long(&ptr, &length)) {
+		error_packet(remcom_out_buffer, -EINVAL);
+		return;
+	}
+
+	if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0')
+		error = kgdb_set_sw_break(addr);
+	else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0')
+		error = kgdb_remove_sw_break(addr);
+	else if (remcom_in_buffer[0] == 'Z')
+		error = arch_kgdb_ops.set_hw_breakpoint(addr,
+			(int)length, *bpt_type);
+	else if (remcom_in_buffer[0] == 'z')
+		error = arch_kgdb_ops.remove_hw_breakpoint(addr,
+			(int) length, *bpt_type);
+
+	if (error == 0)
+		strcpy(remcom_out_buffer, "OK");
+	else
+		error_packet(remcom_out_buffer, error);
+}
+
+/* Handle the 'C' signal / exception passing packets */
+static int gdb_cmd_exception_pass(struct kgdb_state *ks)
+{
+	/* C09 == pass exception
+	 * C15 == detach kgdb, pass exception
+	 */
+	if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') {
+
+		ks->pass_exception = 1;
+		remcom_in_buffer[0] = 'c';
+
+	} else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') {
+
+		ks->pass_exception = 1;
+		remcom_in_buffer[0] = 'D';
+		remove_all_break();
+		kgdb_connected = 0;
+		return 1;
+
+	} else {
+		error_packet(remcom_out_buffer, -EINVAL);
+		return 0;
+	}
+
+	/* Indicate fall through */
+	return -1;
+}
+
+/*
+ * This function performs all gdbserial command procesing
+ */
+static int gdb_serial_stub(struct kgdb_state *ks)
+{
+	int error = 0;
+	int tmp;
+
+	/* Clear the out buffer. */
+	memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
+
+	if (kgdb_connected) {
+		unsigned char thref[8];
+		char *ptr;
+
+		/* Reply to host that an exception has occurred */
+		ptr = remcom_out_buffer;
+		*ptr++ = 'T';
+		ptr = pack_hex_byte(ptr, ks->signo);
+		ptr += strlen(strcpy(ptr, "thread:"));
+		int_to_threadref(thref, shadow_pid(current->pid));
+		ptr = pack_threadid(ptr, thref);
+		*ptr++ = ';';
+		put_packet(remcom_out_buffer);
+	}
+
+	kgdb_usethread = kgdb_info[ks->cpu].task;
+	ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid);
+	ks->pass_exception = 0;
+
+	while (1) {
+		error = 0;
+
+		/* Clear the out buffer. */
+		memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
+
+		get_packet(remcom_in_buffer);
+
+		switch (remcom_in_buffer[0]) {
+		case '?': /* gdbserial status */
+			gdb_cmd_status(ks);
+			break;
+		case 'g': /* return the value of the CPU registers */
+			gdb_cmd_getregs(ks);
+			break;
+		case 'G': /* set the value of the CPU registers - return OK */
+			gdb_cmd_setregs(ks);
+			break;
+		case 'm': /* mAA..AA,LLLL  Read LLLL bytes at address AA..AA */
+			gdb_cmd_memread(ks);
+			break;
+		case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
+			gdb_cmd_memwrite(ks);
+			break;
+		case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
+			gdb_cmd_binwrite(ks);
+			break;
+			/* kill or detach. KGDB should treat this like a
+			 * continue.
+			 */
+		case 'D': /* Debugger detach */
+		case 'k': /* Debugger detach via kill */
+			gdb_cmd_detachkill(ks);
+			goto default_handle;
+		case 'R': /* Reboot */
+			if (gdb_cmd_reboot(ks))
+				goto default_handle;
+			break;
+		case 'q': /* query command */
+			gdb_cmd_query(ks);
+			break;
+		case 'H': /* task related */
+			gdb_cmd_task(ks);
+			break;
+		case 'T': /* Query thread status */
+			gdb_cmd_thread(ks);
+			break;
+		case 'z': /* Break point remove */
+		case 'Z': /* Break point set */
+			gdb_cmd_break(ks);
+			break;
+		case 'C': /* Exception passing */
+			tmp = gdb_cmd_exception_pass(ks);
+			if (tmp > 0)
+				goto default_handle;
+			if (tmp == 0)
+				break;
+			/* Fall through on tmp < 0 */
+		case 'c': /* Continue packet */
+		case 's': /* Single step packet */
+			if (kgdb_contthread && kgdb_contthread != current) {
+				/* Can't switch threads in kgdb */
+				error_packet(remcom_out_buffer, -EINVAL);
+				break;
+			}
+			kgdb_activate_sw_breakpoints();
+			/* Fall through to default processing */
+		default:
+default_handle:
+			error = kgdb_arch_handle_exception(ks->ex_vector,
+						ks->signo,
+						ks->err_code,
+						remcom_in_buffer,
+						remcom_out_buffer,
+						ks->linux_regs);
+			/*
+			 * Leave cmd processing on error, detach,
+			 * kill, continue, or single step.
+			 */
+			if (error >= 0 || remcom_in_buffer[0] == 'D' ||
+			    remcom_in_buffer[0] == 'k') {
+				error = 0;
+				goto kgdb_exit;
+			}
+
+		}
+
+		/* reply to the request */
+		put_packet(remcom_out_buffer);
+	}
+
+kgdb_exit:
+	if (ks->pass_exception)
+		error = 1;
+	return error;
+}
+
+static int kgdb_reenter_check(struct kgdb_state *ks)
+{
+	unsigned long addr;
+
+	if (atomic_read(&kgdb_active) != raw_smp_processor_id())
+		return 0;
+
+	/* Panic on recursive debugger calls: */
+	exception_level++;
+	addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
+	kgdb_deactivate_sw_breakpoints();
+
+	/*
+	 * If the break point removed ok at the place exception
+	 * occurred, try to recover and print a warning to the end
+	 * user because the user planted a breakpoint in a place that
+	 * KGDB needs in order to function.
+	 */
+	if (kgdb_remove_sw_break(addr) == 0) {
+		exception_level = 0;
+		kgdb_skipexception(ks->ex_vector, ks->linux_regs);
+		kgdb_activate_sw_breakpoints();
+		printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed\n");
+		WARN_ON_ONCE(1);
+
+		return 1;
+	}
+	remove_all_break();
+	kgdb_skipexception(ks->ex_vector, ks->linux_regs);
+
+	if (exception_level > 1) {
+		dump_stack();
+		panic("Recursive entry to debugger");
+	}
+
+	printk(KERN_CRIT "KGDB: re-enter exception: ALL breakpoints killed\n");
+	dump_stack();
+	panic("Recursive entry to debugger");
+
+	return 1;
+}
+
+/*
+ * kgdb_handle_exception() - main entry point from a kernel exception
+ *
+ * Locking hierarchy:
+ *	interface locks, if any (begin_session)
+ *	kgdb lock (kgdb_active)
+ */
+int
+kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
+{
+	struct kgdb_state kgdb_var;
+	struct kgdb_state *ks = &kgdb_var;
+	unsigned long flags;
+	int error = 0;
+	int i, cpu;
+
+	ks->cpu			= raw_smp_processor_id();
+	ks->ex_vector		= evector;
+	ks->signo		= signo;
+	ks->ex_vector		= evector;
+	ks->err_code		= ecode;
+	ks->kgdb_usethreadid	= 0;
+	ks->linux_regs		= regs;
+
+	if (kgdb_reenter_check(ks))
+		return 0; /* Ouch, double exception ! */
+
+acquirelock:
+	/*
+	 * Interrupts will be restored by the 'trap return' code, except when
+	 * single stepping.
+	 */
+	local_irq_save(flags);
+
+	cpu = raw_smp_processor_id();
+
+	/*
+	 * Acquire the kgdb_active lock:
+	 */
+	while (atomic_cmpxchg(&kgdb_active, -1, cpu) != -1)
+		cpu_relax();
+
+	/*
+	 * Do not start the debugger connection on this CPU if the last
+	 * instance of the exception handler wanted to come into the
+	 * debugger on a different CPU via a single step
+	 */
+	if (atomic_read(&kgdb_cpu_doing_single_step) != -1 &&
+	    atomic_read(&kgdb_cpu_doing_single_step) != cpu) {
+
+		atomic_set(&kgdb_active, -1);
+		local_irq_restore(flags);
+
+		goto acquirelock;
+	}
+
+	if (!kgdb_io_ready(1)) {
+		error = 1;
+		goto kgdb_restore; /* No I/O connection, so resume the system */
+	}
+
+	/*
+	 * Don't enter if we have hit a removed breakpoint.
+	 */
+	if (kgdb_skipexception(ks->ex_vector, ks->linux_regs))
+		goto kgdb_restore;
+
+	/* Call the I/O driver's pre_exception routine */
+	if (kgdb_io_ops->pre_exception)
+		kgdb_io_ops->pre_exception();
+
+	kgdb_info[ks->cpu].debuggerinfo = ks->linux_regs;
+	kgdb_info[ks->cpu].task = current;
+
+	kgdb_disable_hw_debug(ks->linux_regs);
+
+	/*
+	 * Get the passive CPU lock which will hold all the non-primary
+	 * CPU in a spin state while the debugger is active
+	 */
+	if (!kgdb_single_step || !kgdb_contthread) {
+		for (i = 0; i < NR_CPUS; i++)
+			atomic_set(&passive_cpu_wait[i], 1);
+	}
+
+#ifdef CONFIG_SMP
+	/* Signal the other CPUs to enter kgdb_wait() */
+	if (!kgdb_single_step || !kgdb_contthread)
+		kgdb_roundup_cpus(flags);
+#endif
+
+	/*
+	 * spin_lock code is good enough as a barrier so we don't
+	 * need one here:
+	 */
+	atomic_set(&cpu_in_kgdb[ks->cpu], 1);
+
+	/*
+	 * Wait for the other CPUs to be notified and be waiting for us:
+	 */
+	for_each_online_cpu(i) {
+		while (!atomic_read(&cpu_in_kgdb[i]))
+			cpu_relax();
+	}
+
+	/*
+	 * At this point the primary processor is completely
+	 * in the debugger and all secondary CPUs are quiescent
+	 */
+	kgdb_post_primary_code(ks->linux_regs, ks->ex_vector, ks->err_code);
+	kgdb_deactivate_sw_breakpoints();
+	kgdb_single_step = 0;
+	kgdb_contthread = NULL;
+	exception_level = 0;
+
+	/* Talk to debugger with gdbserial protocol */
+	error = gdb_serial_stub(ks);
+
+	/* Call the I/O driver's post_exception routine */
+	if (kgdb_io_ops->post_exception)
+		kgdb_io_ops->post_exception();
+
+	kgdb_info[ks->cpu].debuggerinfo = NULL;
+	kgdb_info[ks->cpu].task = NULL;
+	atomic_set(&cpu_in_kgdb[ks->cpu], 0);
+
+	if (!kgdb_single_step || !kgdb_contthread) {
+		for (i = NR_CPUS-1; i >= 0; i--)
+			atomic_set(&passive_cpu_wait[i], 0);
+		/*
+		 * Wait till all the CPUs have quit
+		 * from the debugger.
+		 */
+		for_each_online_cpu(i) {
+			while (atomic_read(&cpu_in_kgdb[i]))
+				cpu_relax();
+		}
+	}
+
+kgdb_restore:
+	/* Free kgdb_active */
+	atomic_set(&kgdb_active, -1);
+	local_irq_restore(flags);
+
+	return error;
+}
+
+int kgdb_nmicallback(int cpu, void *regs)
+{
+#ifdef CONFIG_SMP
+	if (!atomic_read(&cpu_in_kgdb[cpu]) &&
+			atomic_read(&kgdb_active) != cpu) {
+		kgdb_wait((struct pt_regs *)regs);
+		return 0;
+	}
+#endif
+	return 1;
+}
+
+void kgdb_console_write(struct console *co, const char *s, unsigned count)
+{
+	unsigned long flags;
+
+	/* If we're debugging, or KGDB has not connected, don't try
+	 * and print. */
+	if (!kgdb_connected || atomic_read(&kgdb_active) != -1)
+		return;
+
+	local_irq_save(flags);
+	kgdb_msg_write(s, count);
+	local_irq_restore(flags);
+}
+
+static struct console kgdbcons = {
+	.name		= "kgdb",
+	.write		= kgdb_console_write,
+	.flags		= CON_PRINTBUFFER | CON_ENABLED,
+	.index		= -1,
+};
+
+#ifdef CONFIG_MAGIC_SYSRQ
+static void sysrq_handle_gdb(int key, struct tty_struct *tty)
+{
+	if (!kgdb_io_ops) {
+		printk(KERN_CRIT "ERROR: No KGDB I/O module available\n");
+		return;
+	}
+	if (!kgdb_connected)
+		printk(KERN_CRIT "Entering KGDB\n");
+
+	kgdb_breakpoint();
+}
+
+static struct sysrq_key_op sysrq_gdb_op = {
+	.handler	= sysrq_handle_gdb,
+	.help_msg	= "Gdb",
+	.action_msg	= "GDB",
+};
+#endif
+
+static void kgdb_register_callbacks(void)
+{
+	if (!kgdb_io_module_registered) {
+		kgdb_io_module_registered = 1;
+		kgdb_arch_init();
+#ifdef CONFIG_MAGIC_SYSRQ
+		register_sysrq_key('g', &sysrq_gdb_op);
+#endif
+		if (kgdb_use_con && !kgdb_con_registered) {
+			register_console(&kgdbcons);
+			kgdb_con_registered = 1;
+		}
+	}
+}
+
+static void kgdb_unregister_callbacks(void)
+{
+	/*
+	 * When this routine is called KGDB should unregister from the
+	 * panic handler and clean up, making sure it is not handling any
+	 * break exceptions at the time.
+	 */
+	if (kgdb_io_module_registered) {
+		kgdb_io_module_registered = 0;
+		kgdb_arch_exit();
+#ifdef CONFIG_MAGIC_SYSRQ
+		unregister_sysrq_key('g', &sysrq_gdb_op);
+#endif
+		if (kgdb_con_registered) {
+			unregister_console(&kgdbcons);
+			kgdb_con_registered = 0;
+		}
+	}
+}
+
+static void kgdb_initial_breakpoint(void)
+{
+	kgdb_break_asap = 0;
+
+	printk(KERN_CRIT "kgdb: Waiting for connection from remote gdb...\n");
+	kgdb_breakpoint();
+}
+
+/**
+ *	kkgdb_register_io_module - register KGDB IO module
+ *	@new_kgdb_io_ops: the io ops vector
+ *
+ *	Register it with the KGDB core.
+ */
+int kgdb_register_io_module(struct kgdb_io *new_kgdb_io_ops)
+{
+	int err;
+
+	spin_lock(&kgdb_registration_lock);
+
+	if (kgdb_io_ops) {
+		spin_unlock(&kgdb_registration_lock);
+
+		printk(KERN_ERR "kgdb: Another I/O driver is already "
+				"registered with KGDB.\n");
+		return -EBUSY;
+	}
+
+	if (new_kgdb_io_ops->init) {
+		err = new_kgdb_io_ops->init();
+		if (err) {
+			spin_unlock(&kgdb_registration_lock);
+			return err;
+		}
+	}
+
+	kgdb_io_ops = new_kgdb_io_ops;
+
+	spin_unlock(&kgdb_registration_lock);
+
+	printk(KERN_INFO "kgdb: Registered I/O driver %s.\n",
+	       new_kgdb_io_ops->name);
+
+	/* Arm KGDB now. */
+	kgdb_register_callbacks();
+
+	if (kgdb_break_asap)
+		kgdb_initial_breakpoint();
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kgdb_register_io_module);
+
+/**
+ *	kkgdb_unregister_io_module - unregister KGDB IO module
+ *	@old_kgdb_io_ops: the io ops vector
+ *
+ *	Unregister it with the KGDB core.
+ */
+void kgdb_unregister_io_module(struct kgdb_io *old_kgdb_io_ops)
+{
+	BUG_ON(kgdb_connected);
+
+	/*
+	 * KGDB is no longer able to communicate out, so
+	 * unregister our callbacks and reset state.
+	 */
+	kgdb_unregister_callbacks();
+
+	spin_lock(&kgdb_registration_lock);
+
+	WARN_ON_ONCE(kgdb_io_ops != old_kgdb_io_ops);
+	kgdb_io_ops = NULL;
+
+	spin_unlock(&kgdb_registration_lock);
+
+	printk(KERN_INFO
+		"kgdb: Unregistered I/O driver %s, debugger disabled.\n",
+		old_kgdb_io_ops->name);
+}
+EXPORT_SYMBOL_GPL(kgdb_unregister_io_module);
+
+/**
+ * kgdb_breakpoint - generate breakpoint exception
+ *
+ * This function will generate a breakpoint exception.  It is used at the
+ * beginning of a program to sync up with a debugger and can be used
+ * otherwise as a quick means to stop program execution and "break" into
+ * the debugger.
+ */
+void kgdb_breakpoint(void)
+{
+	atomic_set(&kgdb_setting_breakpoint, 1);
+	wmb(); /* Sync point before breakpoint */
+	arch_kgdb_breakpoint();
+	wmb(); /* Sync point after breakpoint */
+	atomic_set(&kgdb_setting_breakpoint, 0);
+}
+EXPORT_SYMBOL_GPL(kgdb_breakpoint);
+
+static int __init opt_kgdb_wait(char *str)
+{
+	kgdb_break_asap = 1;
+
+	if (kgdb_io_module_registered)
+		kgdb_initial_breakpoint();
+
+	return 0;
+}
+
+early_param("kgdbwait", opt_kgdb_wait);
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index d41ef6b..97a152c 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -32,6 +32,7 @@
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/kobject.h>
+#include <linux/pid.h>
 #include <linux/net.h>
 #include <linux/sysrq.h>
 #include <linux/highuid.h>
@@ -71,7 +72,6 @@ extern int max_threads;
 extern int core_uses_pid;
 extern int suid_dumpable;
 extern char core_pattern[];
-extern int pid_max;
 extern int min_free_kbytes;
 extern int pid_max_min, pid_max_max;
 extern int sysctl_drop_caches;
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index a370fe8..a904916 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -618,3 +618,5 @@ config PROVIDE_OHCI1394_DMA_INIT
 	  See Documentation/debugging-via-ohci1394.txt for more information.
 
 source "samples/Kconfig"
+
+source "lib/Kconfig.kgdb"
diff --git a/lib/Kconfig.kgdb b/lib/Kconfig.kgdb
new file mode 100644
index 0000000..9631ba3
--- /dev/null
+++ b/lib/Kconfig.kgdb
@@ -0,0 +1,27 @@
+
+menuconfig KGDB
+	bool "KGDB: kernel debugging with remote gdb"
+	select FRAME_POINTER
+	depends on HAVE_ARCH_KGDB
+	depends on DEBUG_KERNEL && EXPERIMENTAL
+	help
+	  If you say Y here, it will be possible to remotely debug the
+	  kernel using gdb.  Documentation of kernel debugger is available
+	  at http://kgdb.sourceforge.net as well as in DocBook form
+	  in Documentation/DocBook/.  If unsure, say N.
+
+config HAVE_ARCH_KGDB_SHADOW_INFO
+	bool
+
+config HAVE_ARCH_KGDB
+	bool
+
+config KGDB_SERIAL_CONSOLE
+	tristate "KGDB: use kgdb over the serial console"
+	depends on KGDB
+	select CONSOLE_POLL
+	select MAGIC_SYSRQ
+	default y
+	help
+	  Share a serial console with kgdb. Sysrq-g must be used
+	  to break in initially.
diff --git a/mm/Makefile b/mm/Makefile
index 9f117ba..fb9e7ac 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -8,7 +8,7 @@ mmu-$(CONFIG_MMU)	:= fremap.o highmem.o madvise.o memory.o mincore.o \
 			   vmalloc.o
 
 obj-y			:= bootmem.o filemap.o mempool.o oom_kill.o fadvise.o \
-			   page_alloc.o page-writeback.o pdflush.o \
+			   maccess.o page_alloc.o page-writeback.o pdflush.o \
 			   readahead.o swap.o truncate.o vmscan.o \
 			   prio_tree.o util.o mmzone.o vmstat.o backing-dev.o \
 			   page_isolation.o $(mmu-y)
diff --git a/mm/maccess.c b/mm/maccess.c
new file mode 100644
index 0000000..24f81b9
--- /dev/null
+++ b/mm/maccess.c
@@ -0,0 +1,49 @@
+/*
+ * Access kernel memory without faulting.
+ */
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+
+/**
+ * probe_kernel_read(): safely attempt to read from a location
+ * @dst: pointer to the buffer that shall take the data
+ * @src: address to read from
+ * @size: size of the data chunk
+ *
+ * Safely read from address @src to the buffer at @dst.  If a kernel fault
+ * happens, handle that and return -EFAULT.
+ */
+long probe_kernel_read(void *dst, void *src, size_t size)
+{
+	long ret;
+
+	pagefault_disable();
+	ret = __copy_from_user_inatomic(dst,
+			(__force const void __user *)src, size);
+	pagefault_enable();
+
+	return ret ? -EFAULT : 0;
+}
+EXPORT_SYMBOL_GPL(probe_kernel_read);
+
+/**
+ * probe_kernel_write(): safely attempt to write to a location
+ * @dst: address to write to
+ * @src: pointer to the data that shall be written
+ * @size: size of the data chunk
+ *
+ * Safely write to address @dst from the buffer at @src.  If a kernel fault
+ * happens, handle that and return -EFAULT.
+ */
+long probe_kernel_write(void *dst, void *src, size_t size)
+{
+	long ret;
+
+	pagefault_disable();
+	ret = __copy_to_user_inatomic((__force void __user *)dst, src, size);
+	pagefault_enable();
+
+	return ret ? -EFAULT : 0;
+}
+EXPORT_SYMBOL_GPL(probe_kernel_write);

Re: [git pull] kgdb-light -v9

[Andi Kleen]

On Tue, Feb 12, 2008 at 12:03:35AM +0100, Ingo Molnar wrote:
> > The synchronization code looks as bad as it was before.

First nobody answered the "kgdb clean enough for a module"
high level question yet. Is it good enough for that?

> 
> i reworked and cleaned up all the kgdb locking code completely. No more 
> NR_CPUS spinlocks, there's now proper use of barriers, etc. No more 
> silly "timeouts" for locking either ... There's now a very well-defined 

A timeout for waiting for other CPUs is actually not a bad idea for a 
debugger. After all you still want to debug even if some other CPUs
are dead.

> and clean locking state-machine for the primary CPU and the secondary 
> CPUs. I re-tested it all on SMP hardware as well.

If it's very clean you should consider sharing it with kdump.

> previously Mark indicated some sort of sprintf return value breakage he 
> observed, and kgdb would rely on sprintf return values so i'm inclined 
> to leave it as-is. We can fix that later, it's not critical.

Pretty much all the proc output and sysfs show functions rely on these return 
values, so if there is a problem it is likely very obscure.

> +	gdb_regs[GDB_BP]	= *(unsigned long *)p->thread.sp;
> +#ifdef CONFIG_X86_32
> +	gdb_regs[GDB_DS]	= __KERNEL_DS;
> +	gdb_regs[GDB_ES]	= __KERNEL_DS;
> +	gdb_regs[GDB_PS]	= 0;
> +	gdb_regs[GDB_CS]	= __KERNEL_CS;
> +	gdb_regs[GDB_PC]	= p->thread.ip;
> +	gdb_regs[GDB_SS]	= __KERNEL_DS;
> +	gdb_regs[GDB_FS]	= 0xFFFF;
> +	gdb_regs[GDB_GS]	= 0xFFFF;
> +#else
> +	gdb_regs[GDB_PS]	= *(unsigned long *)(p->thread.sp + 8);
> +	gdb_regs[GDB_PC]	= 0;
> +	gdb_regs[GDB_R8]	= 0;
> +	gdb_regs[GDB_R9]	= 0;
> +	gdb_regs[GDB_R10]	= 0;
> +	gdb_regs[GDB_R11]	= 0;
> +	gdb_regs[GDB_R12]	= 0;
> +	gdb_regs[GDB_R13]	= 0;
> +	gdb_regs[GDB_R14]	= 0;
> +	gdb_regs[GDB_R15]	= 0;

The 64bit gdb actually supports segment registers:

static int amd64_linux_gregset64_reg_offset[] =
{
  RAX * 8, RBX * 8,             /* %rax, %rbx */
  RCX * 8, RDX * 8,             /* %rcx, %rdx */
  RSI * 8, RDI * 8,             /* %rsi, %rdi */
  RBP * 8, RSP * 8,             /* %rbp, %rsp */
  R8 * 8, R9 * 8,               /* %r8 ... */
  R10 * 8, R11 * 8,
  R12 * 8, R13 * 8,
  R14 * 8, R15 * 8,             /* ... %r15 */
  RIP * 8, EFLAGS * 8,          /* %rip, %eflags */
  CS * 8, SS * 8,               /* %cs, %ss */
  DS * 8, ES * 8,               /* %ds, %es */
  FS * 8, GS * 8,               /* %fs, %gs */
  -1, -1, -1, -1, -1, -1, -1, -1,
  -1, -1, -1, -1, -1, -1, -1, -1,
  -1, -1, -1, -1, -1, -1, -1, -1,
  -1, -1, -1, -1, -1, -1, -1, -1, -1,
  ORIG_RAX * 8
};

> + *
> + *	This function will be called if the particular architecture must
> + *	disable hardware debugging while it is processing gdb packets or
> + *	handling exception.
> + */
> +void kgdb_disable_hw_debug(struct pt_regs *regs)
> +{
> +	/* Disable hardware debugging while we are in kgdb: */
> +	set_debugreg(0UL, 7);

You silently overwrite any user ptrace hw breakpoints right? To do it cleanly 
would still require a reservation frame work.

> +/**
> + *	kgdb_arch_handle_exception - Handle architecture specific GDB packets.

All the kerneldoc comments are useless if you don't add the file
to Documentation/DocBook/*.tmpl

> +static int __kgdb_notify(struct die_args *args, unsigned long cmd)
> +{
> +	struct pt_regs *regs = args->regs;
> +
> +	switch (cmd) {
> +	case DIE_NMI:
> +		if (atomic_read(&kgdb_active) != -1) {
> +			/* KGDB CPU roundup */
> +			kgdb_nmicallback(raw_smp_processor_id(), regs);
> +			return NOTIFY_STOP;
> +		}
> +		return NOTIFY_DONE;
> +
> +	case DIE_NMI_IPI:
> +		if (atomic_read(&kgdb_active) != -1) {
> +			/* KGDB CPU roundup: */
> +			if (kgdb_nmicallback(raw_smp_processor_id(), regs))
> +				return NOTIFY_DONE;
> +			return NOTIFY_STOP;
> +		}
> +		return NOTIFY_DONE;
> +
> +	case DIE_NMIWATCHDOG:
> +		if (atomic_read(&kgdb_active) != -1) {

I don't think that case should happen during roundup for once. If it happens 
something is wrong.

In fact both handling DIE_NMI and DIE_NMI_IPI is fishy too.

> +			/* KGDB CPU roundup: */
> +			kgdb_nmicallback(raw_smp_processor_id(), regs);
> +			return NOTIFY_STOP;
> +		}
> +		/* Enter debugger: */
> +		break;
> +
> +	case DIE_DEBUG:
> +		if (atomic_read(&kgdb_cpu_doing_single_step) ==
> +			raw_smp_processor_id() &&
> +			user_mode(regs))
> +			return single_step_cont(regs, args);
> +		/* fall through */
> +	default:
> +		if (user_mode(regs))
> +			return NOTIFY_DONE;

That seems weird. I think other parts try to support user mode debugging
too. In theory there is no reason it shouldn't be able to do this
(except that you have to make sure to not break regular gdb of course) 

> +
> +static struct notifier_block kgdb_notifier = {
> +	.notifier_call	= kgdb_notify,
> +
> +	/*
> +	 * Lowest-prio notifier priority, we want to be notified last:
> +	 */
> +	.priority	= -INT_MAX,

This means kcrash will have priority won't it? Doesn't seem correct.

> +	int			pass_exception;
> +	long			threadid;
> +	long			kgdb_usethreadid;
> +	struct pt_regs		*linux_regs;
> +};
> +
> +static struct debuggerinfo_struct {
> +	void			*debuggerinfo;
> +	struct task_struct	*task;
> +} kgdb_info[NR_CPUS];

> +int __weak kgdb_validate_break_address(unsigned long addr)
> +{
> +	char tmp_variable[BREAK_INSTR_SIZE];
> +
> +	return probe_kernel_read(tmp_variable, (char *)addr, BREAK_INSTR_SIZE);

Ok I have not checked, but I hope you have strong protections against
reentry of the debugger just in case an exception here falls down to
the die notifiers

> +{
> +	return probe_kernel_write((char *)addr,
> +				  (char *)bundle, BREAK_INSTR_SIZE);
> +}
> +
> +unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs)
> +{
> +	return instruction_pointer(regs);

That wrapper should not be needed; everybody can use instruction_pointer()
directly, no?


> +static const char	hexchars[] = "0123456789abcdef";
> +
> +static int hex(char ch)

... Ok i already commented on the hex mess.


> +{
> +	error = -error;
> +	pkt[0] = 'E';
> +	pkt[1] = hexchars[(error / 10)];
> +	pkt[2] = hexchars[(error % 10)];

e.g. you surely don't need sprintf return values for that one.

> +static struct task_struct *getthread(struct pt_regs *regs, int tid)
> +{
> +	if (num_online_cpus() && (tid >= pid_max + num_online_cpus()))
> +		return NULL;

I still don't think this check makes sense.

> +
> +	if (tid >= pid_max)
> +		return idle_task(tid - pid_max);

Hmm, so idle thread numbers depend on a sysctl? That seems weird.
Would be probably better to just give them negative numbers.



> +
> +	if (!tid)
> +		return NULL;
> +
> +	/*
> +	 * find_task_by_pid() does not take the tasklist lock anymore
> +	 * but is nicely RCU locked - hence is a pretty resilient
> +	 * thing to use:
> +	 */
> +	return find_task_by_pid(tid);

You don't think find_task_by_pid() will handle 0 tid?


> +
> +static inline int shadow_pid(int realpid)
> +{
> +	if (realpid)
> +		return realpid;
> +
> +	return pid_max + raw_smp_processor_id();

Whatever that shadowpid is. Seems like a weird concept.

> +	if (strcmp(remcom_in_buffer, "R0") == 0) {
> +		printk(KERN_CRIT "Executing reboot\n");
> +		strcpy(remcom_out_buffer, "OK");
> +		put_packet(remcom_out_buffer);
> +
> +		/*
> +		 * Execution should not return from
> +		 * machine_restart()
> +		 */
> +		machine_restart(NULL);

It's still likely to deadlock on MP I think

[...] Haven't read further.

-Andi

Re: [git pull] kgdb-light -v9

[Sam Ravnborg]

> 
> > +/**
> > + *	kgdb_arch_handle_exception - Handle architecture specific GDB packets.
> 
> All the kerneldoc comments are useless if you don't add the file
> to Documentation/DocBook/*.tmpl
1) The content is valid no matter the formatting
2) It is a well known format
3) And it is widely used

Using a wellknown format does not require it to be postprocessed.
It is by far better than "one-format-for-each-developer".

	Sam

Re: [git pull] kgdb-light -v9

[Roland McGrath]

> You silently overwrite any user ptrace hw breakpoints right? To do it cleanly 
> would still require a reservation frame work.

There was work underway on that before (hw_breakpoint).  I'm not entirely
sure you want to use fancy stuff like that in kgdb.  It's nice for kgdb to
be as self-contained as possible, so you can debug everything else with it.
If you're going to rely on lots of higher-level infrastructure, it could be
using kprobes for its software breakpoint handling, too.

At any rate, I think it would be good if the hw breakpoint support in kgdb
were chopped out into a separate patch.  First make kgdb work with no code
touching debug registers at all.  Then a second patch can add the hw
breakpoint support.  The latter one can be mulled over or replaced with a
hw_breakpoint merge or just put off for a while because it's a big can of
worms to multiplex the use of the debug registers.


Thanks,
Roland

Re: [git pull] kgdb-light -v9

[Ingo Molnar]

* Roland McGrath <roland@redhat.com> wrote:

> At any rate, I think it would be good if the hw breakpoint support in 
> kgdb were chopped out into a separate patch.  First make kgdb work 
> with no code touching debug registers at all.  Then a second patch can 
> add the hw breakpoint support.  The latter one can be mulled over or 
> replaced with a hw_breakpoint merge or just put off for a while 
> because it's a big can of worms to multiplex the use of the debug 
> registers.

agreed, and i've done that now. Thanks,

	Ingo

[git pull] kgdb-light -v10

[Ingo Molnar]

this is kgdb-light, version -v10 (against Linus-latest), and can be 
pulled from:

   git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-kgdb.git

shortlog, diffstat and full patch can be found further below.

in -v10 i have depleted Andi Kleen's (known ;) pool of last-minute 
objections against kgdb. In order of seriosity:

> > +		machine_restart(NULL);
> 
> It's still likely to deadlock on MP I think

correct (just like SysRq-B can hang) - in -v10 i've fixed this by 
changing it to machine_emergency_restart().

> > +static struct task_struct *getthread(struct pt_regs *regs, int tid)
> > +{
> > +	if (num_online_cpus() && (tid >= pid_max + num_online_cpus()))
> > +		return NULL;
> 
> I still don't think this check makes sense.

it's a sensible check, it validates a remote-provided "tid" against the 
range we accept. (It's a bit superfluous as find_task_by_pid() is safe 
enough.)

Anyway, this point is moot because this check is gone in -v10.

> > +
> > +	if (tid >= pid_max)
> > +		return idle_task(tid - pid_max);
> 
> Hmm, so idle thread numbers depend on a sysctl? That seems weird. 
> Would be probably better to just give them negative numbers.

yes, i thought about that too yesterday, but was unsure how the rest of 
the code would code with that. It's no big issue and i have no strong 
feelings either way.

I changed this in -v10 to map idle tasks to negative tids.

> > +	return pid_max + raw_smp_processor_id();
> 
> Whatever that shadowpid is. [...]

GDB wants to track threads, but on the Linux side each idle task has PID 
0, so GDB cannot track them. The shadow PID is this remapped space.

> [...] Seems like a weird concept.

GDB simply needs an ID it can work with - there's nothing weird about 
that.

> > +	/* Disable hardware debugging while we are in kgdb: */
> > +	set_debugreg(0UL, 7);

as Roland explained it, the simplicity and of this code intentional.

Anyway, no strong feelings and it's now fixed in -v10.

> > +/**
> > + *	kgdb_arch_handle_exception - Handle architecture specific GDB packets.
> 
> All the kerneldoc comments are useless if you don't add the file to 
> Documentation/DocBook/*.tmpl

That's wrong: in-source documentation is never useless. If it happens to 
meet DocBook style that's an added bonus. If the DocBook template is 
added later on that's double bonus.

> > +unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs)
> > +{
> > +	return instruction_pointer(regs);
> 
> That wrapper should not be needed; everybody can use 
> instruction_pointer() directly, no?

no, not all architectures have it. This is a weak alias that is 
otherwise not linked into the kernel.

> > +	case DIE_NMIWATCHDOG:
> > +		if (atomic_read(&kgdb_active) != -1) {
> 
> I don't think that case should happen during roundup for once. If it 
> happens something is wrong.

this code is just being a tad over-cautious.

> > +	default:
> > +		if (user_mode(regs))
> > +			return NOTIFY_DONE;
> 
> That seems weird. I think other parts try to support user mode 
> debugging too. In theory there is no reason it shouldn't be able to do 
> this (except that you have to make sure to not break regular gdb of 
> course)

The currently submitted code does not try to support user mode 
debugging. It might be a nice add-on later, if done cleanly and 
correctly enough. If you are interested we welcome patches from you!

> > +	/*
> > +	 * Lowest-prio notifier priority, we want to be notified last:
> > +	 */
> > +	.priority	= -INT_MAX,
> 
> This means kcrash will have priority won't it? Doesn't seem correct.

yes, this means if the user has configured kcrash as well then that will 
have priority over kgdb. This is the intended behavior.

> First nobody answered the "kgdb clean enough for a module" high level 
> question yet. Is it good enough for that?

i disagree that a kernel debugger should necessarily be a kernel module. 
It might be nice at a future stage, but right now it would just 
introduce unnecessary complexity.

> > i reworked and cleaned up all the kgdb locking code completely. No 
> > more NR_CPUS spinlocks, there's now proper use of barriers, etc. No 
> > more silly "timeouts" for locking either ... There's now a very 
> > well-defined
> 
> A timeout for waiting for other CPUs is actually not a bad idea for a 
> debugger. After all you still want to debug even if some other CPUs 
> are dead.

i went for correctness and simplicity first. If a system is hung, the 
debugging CPU might hang too at any time. A timeout on the other hand 
introduces the possibility of a 'dead' CPU just coming back to life 
after the 'timeout', corrupting debugger data. So for now the rule is 
very simple.

timeouts might be an optional "would be nice" feature for later on.

> > previously Mark indicated some sort of sprintf return value breakage 
> > he observed, and kgdb would rely on sprintf return values so i'm 
> > inclined to leave it as-is. We can fix that later, it's not 
> > critical.
> 
> Pretty much all the proc output and sysfs show functions rely on these 
> return values, so if there is a problem it is likely very obscure.

you are wrong, as procfs does not rely on it for a protocol stack. It 
relies on it mostly for user-space "this many bytes were processed" 
return values and those values are often wrong and user-space just 
handles it gratiously.

Anyway, the presence of a few special parsers that impact nothing else 
but kgdb is not even close to being a merge showstopper, it is something 
that can be consolidated later on. We've already got 7 instances of KGDB 
code in the upstream kernel:

  ./sparc/kernel/sparc-stub.c
  ./cris/arch-v32/kernel/kgdb.c
  ./cris/arch-v10/kernel/kgdb.c
  ./mips/kernel/gdb-stub.c
  ./frv/kernel/gdb-stub.c
  ./mn10300/kernel/gdb-stub.c
  ./ppc/kernel/ppc-stub.c

so obviously these parsers work in practice.

	Ingo

------------------>
Ingo Molnar (2):
      uaccess: add probe_kernel_write()
      x86: kgdb support

Jason Wessel (3):
      kgdb: core
      consoles: polling support, kgdboc
      kgdb: document parameters

 Documentation/kernel-parameters.txt |    5 +
 arch/x86/Kconfig                    |    1 +
 arch/x86/kernel/Makefile            |    1 +
 arch/x86/kernel/kgdb.c              |  417 +++++++++
 drivers/char/tty_io.c               |   47 +
 drivers/serial/8250.c               |   58 ++
 drivers/serial/Kconfig              |    3 +
 drivers/serial/Makefile             |    1 +
 drivers/serial/kgdboc.c             |  163 ++++
 drivers/serial/serial_core.c        |   70 ++-
 include/asm-x86/kgdb.h              |   81 ++
 include/linux/kgdb.h                |  271 ++++++
 include/linux/serial_core.h         |    4 +
 include/linux/tty_driver.h          |   12 +
 include/linux/uaccess.h             |   22 +
 kernel/Makefile                     |    1 +
 kernel/kgdb.c                       | 1675 +++++++++++++++++++++++++++++++++++
 lib/Kconfig.debug                   |    2 +
 lib/Kconfig.kgdb                    |   27 +
 mm/Makefile                         |    2 +-
 mm/maccess.c                        |   49 +
 21 files changed, 2908 insertions(+), 4 deletions(-)
 create mode 100644 arch/x86/kernel/kgdb.c
 create mode 100644 drivers/serial/kgdboc.c
 create mode 100644 include/asm-x86/kgdb.h
 create mode 100644 include/linux/kgdb.h
 create mode 100644 kernel/kgdb.c
 create mode 100644 lib/Kconfig.kgdb
 create mode 100644 mm/maccess.c

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index a4fc7fc..6e97307 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -930,6 +930,11 @@ and is between 256 and 4096 characters. It is defined in the file
 	kstack=N	[X86-32,X86-64] Print N words from the kernel stack
 			in oops dumps.
 
+	kgdboc=		[HW] kgdb over consoles.
+			Requires a tty driver that supports console polling.
+			(only serial suported for now)
+			Format: <serial_device>[,baud]
+
 	l2cr=		[PPC]
 
 	lapic		[X86-32,APIC] Enable the local APIC even if BIOS
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index aaed1a3..c8dd8f9 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -21,6 +21,7 @@ config X86
 	select HAVE_IDE
 	select HAVE_OPROFILE
 	select HAVE_KPROBES
+	select HAVE_ARCH_KGDB
 
 config GENERIC_LOCKBREAK
 	def_bool n
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 76ec0f8..4cd39cd 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -58,6 +58,7 @@ obj-$(CONFIG_MODULES)		+= module_$(BITS).o
 obj-$(CONFIG_ACPI_SRAT) 	+= srat_32.o
 obj-$(CONFIG_EFI) 		+= efi.o efi_$(BITS).o efi_stub_$(BITS).o
 obj-$(CONFIG_DOUBLEFAULT) 	+= doublefault_32.o
+obj-$(CONFIG_KGDB)		+= kgdb.o
 obj-$(CONFIG_VM86)		+= vm86_32.o
 obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
 
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
new file mode 100644
index 0000000..bc762d8
--- /dev/null
+++ b/arch/x86/kernel/kgdb.c
@@ -0,0 +1,417 @@
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ */
+
+/*
+ * Copyright (C) 2004 Amit S. Kale <amitkale@linsyssoft.com>
+ * Copyright (C) 2000-2001 VERITAS Software Corporation.
+ * Copyright (C) 2002 Andi Kleen, SuSE Labs
+ * Copyright (C) 2004 LinSysSoft Technologies Pvt. Ltd.
+ * Copyright (C) 2007 MontaVista Software, Inc.
+ * Copyright (C) 2007-2008 Jason Wessel, Wind River Systems, Inc.
+ */
+/****************************************************************************
+ *  Contributor:     Lake Stevens Instrument Division$
+ *  Written by:      Glenn Engel $
+ *  Updated by:	     Amit Kale<akale@veritas.com>
+ *  Updated by:	     Tom Rini <trini@kernel.crashing.org>
+ *  Updated by:	     Jason Wessel <jason.wessel@windriver.com>
+ *  Modified for 386 by Jim Kingdon, Cygnus Support.
+ *  Origianl kgdb, compatibility with 2.1.xx kernel by
+ *  David Grothe <dave@gcom.com>
+ *  Integrated into 2.2.5 kernel by Tigran Aivazian <tigran@sco.com>
+ *  X86_64 changes from Andi Kleen's patch merged by Jim Houston
+ */
+#include <linux/spinlock.h>
+#include <linux/kdebug.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/ptrace.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/kgdb.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+
+#include <asm/apicdef.h>
+#include <asm/system.h>
+
+#ifdef CONFIG_X86_32
+# include <mach_ipi.h>
+#else
+# include <asm/mach_apic.h>
+#endif
+
+/*
+ * Put the error code here just in case the user cares:
+ */
+static int gdb_x86errcode;
+
+/*
+ * Likewise, the vector number here (since GDB only gets the signal
+ * number through the usual means, and that's not very specific):
+ */
+static int gdb_x86vector = -1;
+
+/**
+ *	pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs
+ *	@gdb_regs: A pointer to hold the registers in the order GDB wants.
+ *	@regs: The &struct pt_regs of the current process.
+ *
+ *	Convert the pt_regs in @regs into the format for registers that
+ *	GDB expects, stored in @gdb_regs.
+ */
+void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+	gdb_regs[GDB_AX]	= regs->ax;
+	gdb_regs[GDB_BX]	= regs->bx;
+	gdb_regs[GDB_CX]	= regs->cx;
+	gdb_regs[GDB_DX]	= regs->dx;
+	gdb_regs[GDB_SI]	= regs->si;
+	gdb_regs[GDB_DI]	= regs->di;
+	gdb_regs[GDB_BP]	= regs->bp;
+	gdb_regs[GDB_PS]	= regs->flags;
+	gdb_regs[GDB_PC]	= regs->ip;
+#ifdef CONFIG_X86_32
+	gdb_regs[GDB_DS]	= regs->ds;
+	gdb_regs[GDB_ES]	= regs->es;
+	gdb_regs[GDB_CS]	= regs->cs;
+	gdb_regs[GDB_SS]	= __KERNEL_DS;
+	gdb_regs[GDB_FS]	= 0xFFFF;
+	gdb_regs[GDB_GS]	= 0xFFFF;
+#else
+	gdb_regs[GDB_R8]	= regs->r8;
+	gdb_regs[GDB_R9]	= regs->r9;
+	gdb_regs[GDB_R10]	= regs->r10;
+	gdb_regs[GDB_R11]	= regs->r11;
+	gdb_regs[GDB_R12]	= regs->r12;
+	gdb_regs[GDB_R13]	= regs->r13;
+	gdb_regs[GDB_R14]	= regs->r14;
+	gdb_regs[GDB_R15]	= regs->r15;
+#endif
+	gdb_regs[GDB_SP]	= regs->sp;
+}
+
+/**
+ *	sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs
+ *	@gdb_regs: A pointer to hold the registers in the order GDB wants.
+ *	@p: The &struct task_struct of the desired process.
+ *
+ *	Convert the register values of the sleeping process in @p to
+ *	the format that GDB expects.
+ *	This function is called when kgdb does not have access to the
+ *	&struct pt_regs and therefore it should fill the gdb registers
+ *	@gdb_regs with what has	been saved in &struct thread_struct
+ *	thread field during switch_to.
+ */
+void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
+{
+	gdb_regs[GDB_AX]	= 0;
+	gdb_regs[GDB_BX]	= 0;
+	gdb_regs[GDB_CX]	= 0;
+	gdb_regs[GDB_DX]	= 0;
+	gdb_regs[GDB_SI]	= 0;
+	gdb_regs[GDB_DI]	= 0;
+	gdb_regs[GDB_BP]	= *(unsigned long *)p->thread.sp;
+#ifdef CONFIG_X86_32
+	gdb_regs[GDB_DS]	= __KERNEL_DS;
+	gdb_regs[GDB_ES]	= __KERNEL_DS;
+	gdb_regs[GDB_PS]	= 0;
+	gdb_regs[GDB_CS]	= __KERNEL_CS;
+	gdb_regs[GDB_PC]	= p->thread.ip;
+	gdb_regs[GDB_SS]	= __KERNEL_DS;
+	gdb_regs[GDB_FS]	= 0xFFFF;
+	gdb_regs[GDB_GS]	= 0xFFFF;
+#else
+	gdb_regs[GDB_PS]	= *(unsigned long *)(p->thread.sp + 8);
+	gdb_regs[GDB_PC]	= 0;
+	gdb_regs[GDB_R8]	= 0;
+	gdb_regs[GDB_R9]	= 0;
+	gdb_regs[GDB_R10]	= 0;
+	gdb_regs[GDB_R11]	= 0;
+	gdb_regs[GDB_R12]	= 0;
+	gdb_regs[GDB_R13]	= 0;
+	gdb_regs[GDB_R14]	= 0;
+	gdb_regs[GDB_R15]	= 0;
+#endif
+	gdb_regs[GDB_SP]	= p->thread.sp;
+}
+
+/**
+ *	gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs.
+ *	@gdb_regs: A pointer to hold the registers we've received from GDB.
+ *	@regs: A pointer to a &struct pt_regs to hold these values in.
+ *
+ *	Convert the GDB regs in @gdb_regs into the pt_regs, and store them
+ *	in @regs.
+ */
+void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+	regs->ax		= gdb_regs[GDB_AX];
+	regs->bx		= gdb_regs[GDB_BX];
+	regs->cx		= gdb_regs[GDB_CX];
+	regs->dx		= gdb_regs[GDB_DX];
+	regs->si		= gdb_regs[GDB_SI];
+	regs->di		= gdb_regs[GDB_DI];
+	regs->bp		= gdb_regs[GDB_BP];
+	regs->flags		= gdb_regs[GDB_PS];
+	regs->ip		= gdb_regs[GDB_PC];
+#ifdef CONFIG_X86_32
+	regs->ds		= gdb_regs[GDB_DS];
+	regs->es		= gdb_regs[GDB_ES];
+	regs->cs		= gdb_regs[GDB_CS];
+#else
+	regs->r8		= gdb_regs[GDB_R8];
+	regs->r9		= gdb_regs[GDB_R9];
+	regs->r10		= gdb_regs[GDB_R10];
+	regs->r11		= gdb_regs[GDB_R11];
+	regs->r12		= gdb_regs[GDB_R12];
+	regs->r13		= gdb_regs[GDB_R13];
+	regs->r14		= gdb_regs[GDB_R14];
+	regs->r15		= gdb_regs[GDB_R15];
+#endif
+}
+
+/**
+ *	kgdb_post_primary_code - Save error vector/code numbers.
+ *	@regs: Original pt_regs.
+ *	@e_vector: Original error vector.
+ *	@err_code: Original error code.
+ *
+ *	This is needed on architectures which support SMP and KGDB.
+ *	This function is called after all the slave cpus have been put
+ *	to a know spin state and the primary CPU has control over KGDB.
+ */
+void kgdb_post_primary_code(struct pt_regs *regs, int e_vector, int err_code)
+{
+	/* primary processor is completely in the debugger */
+	gdb_x86vector = e_vector;
+	gdb_x86errcode = err_code;
+}
+
+#ifdef CONFIG_SMP
+/**
+ *	kgdb_roundup_cpus - Get other CPUs into a holding pattern
+ *	@flags: Current IRQ state
+ *
+ *	On SMP systems, we need to get the attention of the other CPUs
+ *	and get them be in a known state.  This should do what is needed
+ *	to get the other CPUs to call kgdb_wait(). Note that on some arches,
+ *	the NMI approach is not used for rounding up all the CPUs. For example,
+ *	in case of MIPS, smp_call_function() is used to roundup CPUs. In
+ *	this case, we have to make sure that interrupts are enabled before
+ *	calling smp_call_function(). The argument to this function is
+ *	the flags that will be used when restoring the interrupts. There is
+ *	local_irq_save() call before kgdb_roundup_cpus().
+ *
+ *	On non-SMP systems, this is not called.
+ */
+void kgdb_roundup_cpus(unsigned long flags)
+{
+	send_IPI_allbutself(APIC_DM_NMI);
+}
+#endif
+
+/**
+ *	kgdb_arch_handle_exception - Handle architecture specific GDB packets.
+ *	@vector: The error vector of the exception that happened.
+ *	@signo: The signal number of the exception that happened.
+ *	@err_code: The error code of the exception that happened.
+ *	@remcom_in_buffer: The buffer of the packet we have read.
+ *	@remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
+ *	@regs: The &struct pt_regs of the current process.
+ *
+ *	This function MUST handle the 'c' and 's' command packets,
+ *	as well packets to set / remove a hardware breakpoint, if used.
+ *	If there are additional packets which the hardware needs to handle,
+ *	they are handled here.  The code should return -1 if it wants to
+ *	process more packets, and a %0 or %1 if it wants to exit from the
+ *	kgdb callback.
+ */
+int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
+			       char *remcomInBuffer, char *remcomOutBuffer,
+			       struct pt_regs *linux_regs)
+{
+	unsigned long addr;
+	char *ptr;
+	int newPC;
+
+	switch (remcomInBuffer[0]) {
+	case 'c':
+	case 's':
+		/* try to read optional parameter, pc unchanged if no parm */
+		ptr = &remcomInBuffer[1];
+		if (kgdb_hex2long(&ptr, &addr))
+			linux_regs->ip = addr;
+		newPC = linux_regs->ip;
+
+		/* clear the trace bit */
+		linux_regs->flags &= ~TF_MASK;
+		atomic_set(&kgdb_cpu_doing_single_step, -1);
+
+		/* set the trace bit if we're stepping */
+		if (remcomInBuffer[0] == 's') {
+			linux_regs->flags |= TF_MASK;
+			kgdb_single_step = 1;
+			if (kgdb_contthread) {
+				atomic_set(&kgdb_cpu_doing_single_step,
+					   raw_smp_processor_id());
+			}
+		}
+
+		return 0;
+	}
+
+	/* this means that we do not want to exit from the handler: */
+	return -1;
+}
+
+static inline int
+single_step_cont(struct pt_regs *regs, struct die_args *args)
+{
+	/*
+	 * Single step exception from kernel space to user space so
+	 * eat the exception and continue the process:
+	 */
+	printk(KERN_ERR "KGDB: trap/step from kernel to user space, "
+			"resuming...\n");
+	kgdb_arch_handle_exception(args->trapnr, args->signr,
+				   args->err, "c", "", regs);
+
+	return NOTIFY_STOP;
+}
+
+static int __kgdb_notify(struct die_args *args, unsigned long cmd)
+{
+	struct pt_regs *regs = args->regs;
+
+	switch (cmd) {
+	case DIE_NMI:
+		if (atomic_read(&kgdb_active) != -1) {
+			/* KGDB CPU roundup */
+			kgdb_nmicallback(raw_smp_processor_id(), regs);
+			return NOTIFY_STOP;
+		}
+		return NOTIFY_DONE;
+
+	case DIE_NMI_IPI:
+		if (atomic_read(&kgdb_active) != -1) {
+			/* KGDB CPU roundup: */
+			if (kgdb_nmicallback(raw_smp_processor_id(), regs))
+				return NOTIFY_DONE;
+			return NOTIFY_STOP;
+		}
+		return NOTIFY_DONE;
+
+	case DIE_NMIWATCHDOG:
+		if (atomic_read(&kgdb_active) != -1) {
+			/* KGDB CPU roundup: */
+			kgdb_nmicallback(raw_smp_processor_id(), regs);
+			return NOTIFY_STOP;
+		}
+		/* Enter debugger: */
+		break;
+
+	case DIE_DEBUG:
+		if (atomic_read(&kgdb_cpu_doing_single_step) ==
+			raw_smp_processor_id() &&
+			user_mode(regs))
+			return single_step_cont(regs, args);
+		/* fall through */
+	default:
+		if (user_mode(regs))
+			return NOTIFY_DONE;
+	}
+
+	if (kgdb_handle_exception(args->trapnr, args->signr, args->err, regs))
+		return NOTIFY_DONE;
+
+	return NOTIFY_STOP;
+}
+
+static int
+kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
+{
+	unsigned long flags;
+	int ret;
+
+	local_irq_save(flags);
+	ret = __kgdb_notify(ptr, cmd);
+	local_irq_restore(flags);
+
+	return ret;
+}
+
+static struct notifier_block kgdb_notifier = {
+	.notifier_call	= kgdb_notify,
+
+	/*
+	 * Lowest-prio notifier priority, we want to be notified last:
+	 */
+	.priority	= -INT_MAX,
+};
+
+/**
+ *	kgdb_arch_init - Perform any architecture specific initalization.
+ *
+ *	This function will handle the initalization of any architecture
+ *	specific callbacks.
+ */
+int kgdb_arch_init(void)
+{
+	return register_die_notifier(&kgdb_notifier);
+}
+
+/**
+ *	kgdb_arch_exit - Perform any architecture specific uninitalization.
+ *
+ *	This function will handle the uninitalization of any architecture
+ *	specific callbacks, for dynamic registration and unregistration.
+ */
+void kgdb_arch_exit(void)
+{
+	unregister_die_notifier(&kgdb_notifier);
+}
+
+/**
+ *
+ *	kgdb_skipexception - Bail of of KGDB when we've been triggered.
+ *	@exception: Exception vector number
+ *	@regs: Current &struct pt_regs.
+ *
+ *	On some architectures we need to skip a breakpoint exception when
+ *	it occurs after a breakpoint has been removed.
+ *
+ * Skip an int3 exception when it occurs after a breakpoint has been
+ * removed. Backtrack eip by 1 since the int3 would have caused it to
+ * increment by 1.
+ */
+int kgdb_skipexception(int exception, struct pt_regs *regs)
+{
+	if (exception == 3 && kgdb_isremovedbreak(regs->ip - 1)) {
+		regs->ip -= 1;
+		return 1;
+	}
+	return 0;
+}
+
+unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs)
+{
+	if (exception == 3)
+		return instruction_pointer(regs) - 1;
+	return instruction_pointer(regs);
+}
+
+struct kgdb_arch arch_kgdb_ops = {
+	/* Breakpoint instruction: */
+	.gdb_bpt_instr		= { 0xcc },
+};
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 613ec81..4d3c701 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -1155,6 +1155,48 @@ static struct tty_driver *get_tty_driver(dev_t device, int *index)
 	return NULL;
 }
 
+#ifdef CONFIG_CONSOLE_POLL
+
+/**
+ *	tty_find_polling_driver	-	find device of a polled tty
+ *	@name: name string to match
+ *	@line: pointer to resulting tty line nr
+ *
+ *	This routine returns a tty driver structure, given a name
+ *	and the condition that the tty driver is capable of polled
+ *	operation.
+ */
+struct tty_driver *tty_find_polling_driver(char *name, int *line)
+{
+	struct tty_driver *p, *res = NULL;
+	int tty_line = 0;
+	char *str;
+
+	mutex_lock(&tty_mutex);
+	/* Search through the tty devices to look for a match */
+	list_for_each_entry(p, &tty_drivers, tty_drivers) {
+		str = name + strlen(p->name);
+		tty_line = simple_strtoul(str, &str, 10);
+		if (*str == ',')
+			str++;
+		if (*str == '\0')
+			str = 0;
+
+		if (tty_line >= 0 && tty_line <= p->num && p->poll_init &&
+				!p->poll_init(p, tty_line, str)) {
+
+			res = p;
+			*line = tty_line;
+			break;
+		}
+	}
+	mutex_unlock(&tty_mutex);
+
+	return res;
+}
+EXPORT_SYMBOL_GPL(tty_find_polling_driver);
+#endif
+
 /**
  *	tty_check_change	-	check for POSIX terminal changes
  *	@tty: tty to check
@@ -3850,6 +3892,11 @@ void tty_set_operations(struct tty_driver *driver,
 	driver->write_proc = op->write_proc;
 	driver->tiocmget = op->tiocmget;
 	driver->tiocmset = op->tiocmset;
+#ifdef CONFIG_CONSOLE_POLL
+	driver->poll_init = op->poll_init;
+	driver->poll_get_char = op->poll_get_char;
+	driver->poll_put_char = op->poll_put_char;
+#endif
 }
 
 
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 77f7a7f..96a585e 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -1740,6 +1740,60 @@ static inline void wait_for_xmitr(struct uart_8250_port *up, int bits)
 	}
 }
 
+#ifdef CONFIG_CONSOLE_POLL
+/*
+ * Console polling routines for writing and reading from the uart while
+ * in an interrupt or debug context.
+ */
+
+static int serial8250_get_poll_char(struct uart_port *port)
+{
+	struct uart_8250_port *up = (struct uart_8250_port *)port;
+	unsigned char lsr = serial_inp(up, UART_LSR);
+
+	while (!(lsr & UART_LSR_DR))
+		lsr = serial_inp(up, UART_LSR);
+
+	return serial_inp(up, UART_RX);
+}
+
+
+static void serial8250_put_poll_char(struct uart_port *port,
+			 unsigned char c)
+{
+	unsigned int ier;
+	struct uart_8250_port *up = (struct uart_8250_port *)port;
+
+	/*
+	 *	First save the IER then disable the interrupts
+	 */
+	ier = serial_in(up, UART_IER);
+	if (up->capabilities & UART_CAP_UUE)
+		serial_out(up, UART_IER, UART_IER_UUE);
+	else
+		serial_out(up, UART_IER, 0);
+
+	wait_for_xmitr(up, BOTH_EMPTY);
+	/*
+	 *	Send the character out.
+	 *	If a LF, also do CR...
+	 */
+	serial_out(up, UART_TX, c);
+	if (c == 10) {
+		wait_for_xmitr(up, BOTH_EMPTY);
+		serial_out(up, UART_TX, 13);
+	}
+
+	/*
+	 *	Finally, wait for transmitter to become empty
+	 *	and restore the IER
+	 */
+	wait_for_xmitr(up, BOTH_EMPTY);
+	serial_out(up, UART_IER, ier);
+}
+
+#endif /* CONFIG_CONSOLE_POLL */
+
 static int serial8250_startup(struct uart_port *port)
 {
 	struct uart_8250_port *up = (struct uart_8250_port *)port;
@@ -2386,6 +2440,10 @@ static struct uart_ops serial8250_pops = {
 	.request_port	= serial8250_request_port,
 	.config_port	= serial8250_config_port,
 	.verify_port	= serial8250_verify_port,
+#ifdef CONFIG_CONSOLE_POLL
+	.poll_get_char = serial8250_get_poll_char,
+	.poll_put_char = serial8250_put_poll_char,
+#endif
 };
 
 static struct uart_8250_port serial8250_ports[UART_NR];
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index b82595c..5d9667c 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -961,6 +961,9 @@ config SERIAL_CORE
 config SERIAL_CORE_CONSOLE
 	bool
 
+config CONSOLE_POLL
+	bool
+
 config SERIAL_68328
 	bool "68328 serial support"
 	depends on M68328 || M68EZ328 || M68VZ328
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 640cfe4..3cbea54 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -66,4 +66,5 @@ obj-$(CONFIG_SERIAL_UARTLITE) += uartlite.o
 obj-$(CONFIG_SERIAL_NETX) += netx-serial.o
 obj-$(CONFIG_SERIAL_OF_PLATFORM) += of_serial.o
 obj-$(CONFIG_SERIAL_KS8695) += serial_ks8695.o
+obj-$(CONFIG_KGDB_SERIAL_CONSOLE) += kgdboc.o
 obj-$(CONFIG_SERIAL_QE) += ucc_uart.o
diff --git a/drivers/serial/kgdboc.c b/drivers/serial/kgdboc.c
new file mode 100644
index 0000000..3418307
--- /dev/null
+++ b/drivers/serial/kgdboc.c
@@ -0,0 +1,163 @@
+/*
+ * Based on the same principle as kgdboe using the NETPOLL api, this
+ * driver uses a console polling api to implement a gdb serial inteface
+ * which is multiplexed on a console port.
+ *
+ * Maintainer: Jason Wessel <jason.wessel@windriver.com>
+ *
+ * 2007-2008 (c) Jason Wessel - Wind River Systems, Inc.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+#include <linux/kernel.h>
+#include <linux/ctype.h>
+#include <linux/kgdb.h>
+#include <linux/tty.h>
+
+#define MAX_CONFIG_LEN		40
+
+static struct kgdb_io		kgdboc_io_ops;
+
+/* -1 = init not run yet, 0 = unconfigured, 1 = configured. */
+static int configured		= -1;
+
+static char config[MAX_CONFIG_LEN];
+static struct kparam_string kps = {
+	.string			= config,
+	.maxlen			= MAX_CONFIG_LEN,
+};
+
+static struct tty_driver	*kgdb_tty_driver;
+static int			kgdb_tty_line;
+
+static int kgdboc_option_setup(char *opt)
+{
+	if (strlen(opt) > MAX_CONFIG_LEN) {
+		printk(KERN_ERR "kgdboc: config string too long\n");
+		return -ENOSPC;
+	}
+	strcpy(config, opt);
+
+	return 0;
+}
+
+__setup("kgdboc=", kgdboc_option_setup);
+
+static int configure_kgdboc(void)
+{
+	struct tty_driver *p;
+	int tty_line = 0;
+	int err;
+
+	err = kgdboc_option_setup(config);
+	if (err || !strlen(config) || isspace(config[0]))
+		goto noconfig;
+
+	err = -ENODEV;
+
+	p = tty_find_polling_driver(config, &tty_line);
+	if (!p)
+		goto noconfig;
+
+	kgdb_tty_driver = p;
+	kgdb_tty_line = tty_line;
+
+	err = kgdb_register_io_module(&kgdboc_io_ops);
+	if (err)
+		goto noconfig;
+
+	configured = 1;
+
+	return 0;
+
+noconfig:
+	config[0] = 0;
+	configured = 0;
+
+	return err;
+}
+
+static int __init init_kgdboc(void)
+{
+	/* Already configured? */
+	if (configured == 1)
+		return 0;
+
+	return configure_kgdboc();
+}
+
+static void cleanup_kgdboc(void)
+{
+	if (configured == 1)
+		kgdb_unregister_io_module(&kgdboc_io_ops);
+}
+
+static int kgdboc_get_char(void)
+{
+	return kgdb_tty_driver->poll_get_char(kgdb_tty_driver, kgdb_tty_line);
+}
+
+static void kgdboc_put_char(u8 chr)
+{
+	kgdb_tty_driver->poll_put_char(kgdb_tty_driver, kgdb_tty_line, chr);
+}
+
+static int param_set_kgdboc_var(const char *kmessage, struct kernel_param *kp)
+{
+	if (strlen(kmessage) >= MAX_CONFIG_LEN) {
+		printk(KERN_ERR "kgdboc: config string too long\n");
+		return -ENOSPC;
+	}
+
+	/* Only copy in the string if the init function has not run yet */
+	if (configured < 0) {
+		strcpy(config, kmessage);
+		return 0;
+	}
+
+	if (kgdb_connected) {
+		printk(KERN_ERR
+		       "kgdboc: Cannot reconfigure while KGDB is connected.\n");
+
+		return -EBUSY;
+	}
+
+	strcpy(config, kmessage);
+
+	if (configured == 1)
+		cleanup_kgdboc();
+
+	/* Go and configure with the new params. */
+	return configure_kgdboc();
+}
+
+static void kgdboc_pre_exp_handler(void)
+{
+	/* Increment the module count when the debugger is active */
+	if (!kgdb_connected)
+		try_module_get(THIS_MODULE);
+}
+
+static void kgdboc_post_exp_handler(void)
+{
+	/* decrement the module count when the debugger detaches */
+	if (!kgdb_connected)
+		module_put(THIS_MODULE);
+}
+
+static struct kgdb_io kgdboc_io_ops = {
+	.name			= "kgdboc",
+	.read_char		= kgdboc_get_char,
+	.write_char		= kgdboc_put_char,
+	.pre_exception		= kgdboc_pre_exp_handler,
+	.post_exception		= kgdboc_post_exp_handler,
+};
+
+module_init(init_kgdboc);
+module_exit(cleanup_kgdboc);
+module_param_call(kgdboc, param_set_kgdboc_var, param_get_string, &kps, 0644);
+MODULE_PARM_DESC(kgdboc, "<serial_device>[,baud]");
+MODULE_DESCRIPTION("KGDB Console TTY Driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index 0f5a179..cec193b 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -1827,7 +1827,7 @@ uart_get_console(struct uart_port *ports, int nr, struct console *co)
  *	options.  The format of the string is <baud><parity><bits><flow>,
  *	eg: 115200n8r
  */
-void __init
+void
 uart_parse_options(char *options, int *baud, int *parity, int *bits, int *flow)
 {
 	char *s = options;
@@ -1872,7 +1872,7 @@ static const struct baud_rates baud_rates[] = {
  *	@bits: number of data bits
  *	@flow: flow control character - 'r' (rts)
  */
-int __init
+int
 uart_set_options(struct uart_port *port, struct console *co,
 		 int baud, int parity, int bits, int flow)
 {
@@ -1924,7 +1924,12 @@ uart_set_options(struct uart_port *port, struct console *co,
 	port->mctrl |= TIOCM_DTR;
 
 	port->ops->set_termios(port, &termios, &dummy);
-	co->cflag = termios.c_cflag;
+	/*
+	 * Allow the setting of the UART parameters with a NULL console
+	 * too:
+	 */
+	if (co)
+		co->cflag = termios.c_cflag;
 
 	return 0;
 }
@@ -2182,6 +2187,60 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state,
 	}
 }
 
+#ifdef CONFIG_CONSOLE_POLL
+
+static int uart_poll_init(struct tty_driver *driver, int line, char *options)
+{
+	struct uart_driver *drv = driver->driver_state;
+	struct uart_state *state = drv->state + line;
+	struct uart_port *port;
+	int baud = 9600;
+	int bits = 8;
+	int parity = 'n';
+	int flow = 'n';
+
+	if (!state || !state->port)
+		return -1;
+
+	port = state->port;
+	if (!(port->ops->poll_get_char && port->ops->poll_put_char))
+		return -1;
+
+	if (options) {
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+		return uart_set_options(port, NULL, baud, parity, bits, flow);
+	}
+
+	return 0;
+}
+
+static int uart_poll_get_char(struct tty_driver *driver, int line)
+{
+	struct uart_driver *drv = driver->driver_state;
+	struct uart_state *state = drv->state + line;
+	struct uart_port *port;
+
+	if (!state || !state->port)
+		return -1;
+
+	port = state->port;
+	return port->ops->poll_get_char(port);
+}
+
+static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
+{
+	struct uart_driver *drv = driver->driver_state;
+	struct uart_state *state = drv->state + line;
+	struct uart_port *port;
+
+	if (!state || !state->port)
+		return;
+
+	port = state->port;
+	port->ops->poll_put_char(port, ch);
+}
+#endif
+
 static const struct tty_operations uart_ops = {
 	.open		= uart_open,
 	.close		= uart_close,
@@ -2206,6 +2265,11 @@ static const struct tty_operations uart_ops = {
 #endif
 	.tiocmget	= uart_tiocmget,
 	.tiocmset	= uart_tiocmset,
+#ifdef CONFIG_CONSOLE_POLL
+	.poll_init	= uart_poll_init,
+	.poll_get_char	= uart_poll_get_char,
+	.poll_put_char	= uart_poll_put_char,
+#endif
 };
 
 /**
diff --git a/include/asm-x86/kgdb.h b/include/asm-x86/kgdb.h
new file mode 100644
index 0000000..484c475
--- /dev/null
+++ b/include/asm-x86/kgdb.h
@@ -0,0 +1,81 @@
+#ifndef _ASM_KGDB_H_
+#define _ASM_KGDB_H_
+
+/*
+ * Copyright (C) 2001-2004 Amit S. Kale
+ * Copyright (C) 2008 Wind River Systems, Inc.
+ */
+
+/*
+ * BUFMAX defines the maximum number of characters in inbound/outbound
+ * buffers at least NUMREGBYTES*2 are needed for register packets
+ * Longer buffer is needed to list all threads
+ */
+#define BUFMAX			1024
+
+/*
+ *  Note that this register image is in a different order than
+ *  the register image that Linux produces at interrupt time.
+ *
+ *  Linux's register image is defined by struct pt_regs in ptrace.h.
+ *  Just why GDB uses a different order is a historical mystery.
+ */
+#ifdef CONFIG_X86_32
+enum regnames {
+	GDB_AX,			/* 0 */
+	GDB_CX,			/* 1 */
+	GDB_DX,			/* 2 */
+	GDB_BX,			/* 3 */
+	GDB_SP,			/* 4 */
+	GDB_BP,			/* 5 */
+	GDB_SI,			/* 6 */
+	GDB_DI,			/* 7 */
+	GDB_PC,			/* 8 also known as eip */
+	GDB_PS,			/* 9 also known as eflags */
+	GDB_CS,			/* 10 */
+	GDB_SS,			/* 11 */
+	GDB_DS,			/* 12 */
+	GDB_ES,			/* 13 */
+	GDB_FS,			/* 14 */
+	GDB_GS,			/* 15 */
+};
+#else /* ! CONFIG_X86_32 */
+enum regnames {
+	GDB_AX,			/* 0 */
+	GDB_DX,			/* 1 */
+	GDB_CX,			/* 2 */
+	GDB_BX,			/* 3 */
+	GDB_SI,			/* 4 */
+	GDB_DI,			/* 5 */
+	GDB_BP,			/* 6 */
+	GDB_SP,			/* 7 */
+	GDB_R8,			/* 8 */
+	GDB_R9,			/* 9 */
+	GDB_R10,		/* 10 */
+	GDB_R11,		/* 11 */
+	GDB_R12,		/* 12 */
+	GDB_R13,		/* 13 */
+	GDB_R14,		/* 14 */
+	GDB_R15,		/* 15 */
+	GDB_PC,			/* 16 */
+	GDB_PS,			/* 17 */
+};
+#endif /* CONFIG_X86_32 */
+
+/*
+ * Number of bytes of registers:
+ */
+#ifdef CONFIG_X86_32
+# define NUMREGBYTES		64
+#else
+# define NUMREGBYTES		((GDB_PS+1)*8)
+#endif
+
+static inline void arch_kgdb_breakpoint(void)
+{
+	asm("   int $3");
+}
+#define BREAK_INSTR_SIZE	1
+#define CACHE_FLUSH_IS_SAFE	1
+
+#endif				/* _ASM_KGDB_H_ */
diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h
new file mode 100644
index 0000000..b2be3a8
--- /dev/null
+++ b/include/linux/kgdb.h
@@ -0,0 +1,271 @@
+/*
+ * This provides the callbacks and functions that KGDB needs to share between
+ * the core, I/O and arch-specific portions.
+ *
+ * Author: Amit Kale <amitkale@linsyssoft.com> and
+ *         Tom Rini <trini@kernel.crashing.org>
+ *
+ * 2001-2004 (c) Amit S. Kale and 2003-2005 (c) MontaVista Software, Inc.
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2. This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+#ifndef _KGDB_H_
+#define _KGDB_H_
+
+#include <linux/serial_8250.h>
+#include <linux/linkage.h>
+#include <linux/init.h>
+
+#include <asm/atomic.h>
+#include <asm/kgdb.h>
+
+struct pt_regs;
+
+/*
+ *	kgdb_skipexception - Bail of of KGDB when we've been triggered.
+ *	@exception: Exception vector number
+ *	@regs: Current &struct pt_regs.
+ *
+ *	On some architectures we need to skip a breakpoint exception when
+ *	it occurs after a breakpoint has been removed.
+ */
+extern int kgdb_skipexception(int exception, struct pt_regs *regs);
+
+/*
+ *	kgdb_post_primary_code - Save error vector/code numbers.
+ *	@regs: Original pt_regs.
+ *	@e_vector: Original error vector.
+ *	@err_code: Original error code.
+ *
+ *	This is needed on architectures which support SMP and KGDB.
+ *	This function is called after all the secondary cpus have been put
+ *	to a know spin state and the primary CPU has control over KGDB.
+ */
+extern void kgdb_post_primary_code(struct pt_regs *regs, int e_vector,
+				  int err_code);
+
+/*
+ *	kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
+ *	@regs: Current &struct pt_regs.
+ *
+ *	This function will be called if the particular architecture must
+ *	disable hardware debugging while it is processing gdb packets or
+ *	handling exception.
+ */
+extern void kgdb_disable_hw_debug(struct pt_regs *regs);
+
+struct tasklet_struct;
+struct task_struct;
+struct uart_port;
+
+/* To enter the debugger explicitly. */
+void kgdb_breakpoint(void);
+
+extern int kgdb_connected;
+
+extern atomic_t			kgdb_setting_breakpoint;
+extern atomic_t			kgdb_cpu_doing_single_step;
+
+extern struct task_struct	*kgdb_usethread;
+extern struct task_struct	*kgdb_contthread;
+
+enum kgdb_bptype {
+	BP_BREAKPOINT = 0,
+	BP_HARDWARE_BREAKPOINT,
+	BP_WRITE_WATCHPOINT,
+	BP_READ_WATCHPOINT,
+	BP_ACCESS_WATCHPOINT
+};
+
+enum kgdb_bpstate {
+	BP_UNDEFINED = 0,
+	BP_REMOVED,
+	BP_SET,
+	BP_ACTIVE
+};
+
+struct kgdb_bkpt {
+	unsigned long		bpt_addr;
+	unsigned char		saved_instr[BREAK_INSTR_SIZE];
+	enum kgdb_bptype	type;
+	enum kgdb_bpstate	state;
+};
+
+#ifndef KGDB_MAX_BREAKPOINTS
+# define KGDB_MAX_BREAKPOINTS	1000
+#endif
+
+#define KGDB_HW_BREAKPOINT	1
+
+/*
+ * Functions each KGDB-supporting architecture must provide:
+ */
+
+/*
+ *	kgdb_arch_init - Perform any architecture specific initalization.
+ *
+ *	This function will handle the initalization of any architecture
+ *	specific callbacks.
+ */
+extern int kgdb_arch_init(void);
+
+/*
+ *	kgdb_arch_exit - Perform any architecture specific uninitalization.
+ *
+ *	This function will handle the uninitalization of any architecture
+ *	specific callbacks, for dynamic registration and unregistration.
+ */
+extern void kgdb_arch_exit(void);
+
+/*
+ *	pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs
+ *	@gdb_regs: A pointer to hold the registers in the order GDB wants.
+ *	@regs: The &struct pt_regs of the current process.
+ *
+ *	Convert the pt_regs in @regs into the format for registers that
+ *	GDB expects, stored in @gdb_regs.
+ */
+extern void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs);
+
+/*
+ *	sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs
+ *	@gdb_regs: A pointer to hold the registers in the order GDB wants.
+ *	@p: The &struct task_struct of the desired process.
+ *
+ *	Convert the register values of the sleeping process in @p to
+ *	the format that GDB expects.
+ *	This function is called when kgdb does not have access to the
+ *	&struct pt_regs and therefore it should fill the gdb registers
+ *	@gdb_regs with what has	been saved in &struct thread_struct
+ *	thread field during switch_to.
+ */
+extern void
+sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p);
+
+/*
+ *	gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs.
+ *	@gdb_regs: A pointer to hold the registers we've received from GDB.
+ *	@regs: A pointer to a &struct pt_regs to hold these values in.
+ *
+ *	Convert the GDB regs in @gdb_regs into the pt_regs, and store them
+ *	in @regs.
+ */
+extern void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs);
+
+/*
+ *	kgdb_arch_handle_exception - Handle architecture specific GDB packets.
+ *	@vector: The error vector of the exception that happened.
+ *	@signo: The signal number of the exception that happened.
+ *	@err_code: The error code of the exception that happened.
+ *	@remcom_in_buffer: The buffer of the packet we have read.
+ *	@remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
+ *	@regs: The &struct pt_regs of the current process.
+ *
+ *	This function MUST handle the 'c' and 's' command packets,
+ *	as well packets to set / remove a hardware breakpoint, if used.
+ *	If there are additional packets which the hardware needs to handle,
+ *	they are handled here.  The code should return -1 if it wants to
+ *	process more packets, and a %0 or %1 if it wants to exit from the
+ *	kgdb callback.
+ */
+extern int
+kgdb_arch_handle_exception(int vector, int signo, int err_code,
+			   char *remcom_in_buffer,
+			   char *remcom_out_buffer,
+			   struct pt_regs *regs);
+
+/*
+ *	kgdb_roundup_cpus - Get other CPUs into a holding pattern
+ *	@flags: Current IRQ state
+ *
+ *	On SMP systems, we need to get the attention of the other CPUs
+ *	and get them be in a known state.  This should do what is needed
+ *	to get the other CPUs to call kgdb_wait(). Note that on some arches,
+ *	the NMI approach is not used for rounding up all the CPUs. For example,
+ *	in case of MIPS, smp_call_function() is used to roundup CPUs. In
+ *	this case, we have to make sure that interrupts are enabled before
+ *	calling smp_call_function(). The argument to this function is
+ *	the flags that will be used when restoring the interrupts. There is
+ *	local_irq_save() call before kgdb_roundup_cpus().
+ *
+ *	On non-SMP systems, this is not called.
+ */
+extern void kgdb_roundup_cpus(unsigned long flags);
+
+/* Optional functions. */
+extern int kgdb_validate_break_address(unsigned long addr);
+extern int kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr);
+extern int kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle);
+
+/*
+ * struct kgdb_arch - Describe architecture specific values.
+ * @gdb_bpt_instr: The instruction to trigger a breakpoint.
+ * @flags: Flags for the breakpoint, currently just %KGDB_HW_BREAKPOINT.
+ * @set_breakpoint: Allow an architecture to specify how to set a software
+ * breakpoint.
+ * @remove_breakpoint: Allow an architecture to specify how to remove a
+ * software breakpoint.
+ * @set_hw_breakpoint: Allow an architecture to specify how to set a hardware
+ * breakpoint.
+ * @remove_hw_breakpoint: Allow an architecture to specify how to remove a
+ * hardware breakpoint.
+ * @remove_all_hw_break: Allow an architecture to specify how to remove all
+ * hardware breakpoints.
+ * @correct_hw_break: Allow an architecture to specify how to correct the
+ * hardware debug registers.
+ */
+struct kgdb_arch {
+	unsigned char		gdb_bpt_instr[BREAK_INSTR_SIZE];
+	unsigned long		flags;
+
+	int	(*set_breakpoint)(unsigned long, char *);
+	int	(*remove_breakpoint)(unsigned long, char *);
+	int	(*set_hw_breakpoint)(unsigned long, int, enum kgdb_bptype);
+	int	(*remove_hw_breakpoint)(unsigned long, int, enum kgdb_bptype);
+	void	(*remove_all_hw_break)(void);
+	void	(*correct_hw_break)(void);
+};
+
+/*
+ * struct kgdb_io - Describe the interface for an I/O driver to talk with KGDB.
+ * @name: Name of the I/O driver.
+ * @read_char: Pointer to a function that will return one char.
+ * @write_char: Pointer to a function that will write one char.
+ * @flush: Pointer to a function that will flush any pending writes.
+ * @init: Pointer to a function that will initialize the device.
+ * @pre_exception: Pointer to a function that will do any prep work for
+ * the I/O driver.
+ * @post_exception: Pointer to a function that will do any cleanup work
+ * for the I/O driver.
+ */
+struct kgdb_io {
+	const char		*name;
+	int			(*read_char) (void);
+	void			(*write_char) (u8);
+	void			(*flush) (void);
+	int			(*init) (void);
+	void			(*pre_exception) (void);
+	void			(*post_exception) (void);
+};
+
+extern struct kgdb_arch		arch_kgdb_ops;
+
+extern int kgdb_register_io_module(struct kgdb_io *local_kgdb_io_ops);
+extern void kgdb_unregister_io_module(struct kgdb_io *local_kgdb_io_ops);
+
+extern int kgdb_hex2long(char **ptr, long *long_val);
+extern int kgdb_mem2hex(char *mem, char *buf, int count);
+extern int kgdb_hex2mem(char *buf, char *mem, int count);
+
+extern int kgdb_isremovedbreak(unsigned long addr);
+
+extern int
+kgdb_handle_exception(int ex_vector, int signo, int err_code,
+		      struct pt_regs *regs);
+extern int kgdb_nmicallback(int cpu, void *regs);
+
+extern int			kgdb_single_step;
+extern atomic_t			kgdb_active;
+
+#endif /* _KGDB_H_ */
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 1a0b6cf..7d1a46b 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -211,6 +211,10 @@ struct uart_ops {
 	void		(*config_port)(struct uart_port *, int);
 	int		(*verify_port)(struct uart_port *, struct serial_struct *);
 	int		(*ioctl)(struct uart_port *, unsigned int, unsigned long);
+#ifdef CONFIG_CONSOLE_POLL
+	void	(*poll_put_char)(struct uart_port *, unsigned char);
+	int		(*poll_get_char)(struct uart_port *);
+#endif
 };
 
 #define UART_CONFIG_TYPE	(1 << 0)
diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index 85c95cd..21f69ac 100644
--- a/include/linux/tty_driver.h
+++ b/include/linux/tty_driver.h
@@ -125,6 +125,7 @@
 #include <linux/cdev.h>
 
 struct tty_struct;
+struct tty_driver;
 
 struct tty_operations {
 	int  (*open)(struct tty_struct * tty, struct file * filp);
@@ -157,6 +158,11 @@ struct tty_operations {
 	int (*tiocmget)(struct tty_struct *tty, struct file *file);
 	int (*tiocmset)(struct tty_struct *tty, struct file *file,
 			unsigned int set, unsigned int clear);
+#ifdef CONFIG_CONSOLE_POLL
+	int (*poll_init)(struct tty_driver *driver, int line, char *options);
+	int (*poll_get_char)(struct tty_driver *driver, int line);
+	void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
+#endif
 };
 
 struct tty_driver {
@@ -220,6 +226,11 @@ struct tty_driver {
 	int (*tiocmget)(struct tty_struct *tty, struct file *file);
 	int (*tiocmset)(struct tty_struct *tty, struct file *file,
 			unsigned int set, unsigned int clear);
+#ifdef CONFIG_CONSOLE_POLL
+	int (*poll_init)(struct tty_driver *driver, int line, char *options);
+	int (*poll_get_char)(struct tty_driver *driver, int line);
+	void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
+#endif
 
 	struct list_head tty_drivers;
 };
@@ -230,6 +241,7 @@ struct tty_driver *alloc_tty_driver(int lines);
 void put_tty_driver(struct tty_driver *driver);
 void tty_set_operations(struct tty_driver *driver,
 			const struct tty_operations *op);
+extern struct tty_driver *tty_find_polling_driver(char *name, int *line);
 
 /* tty driver magic number */
 #define TTY_DRIVER_MAGIC		0x5402
diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index 975c963..fec6dec 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -84,4 +84,26 @@ static inline unsigned long __copy_from_user_nocache(void *to,
 		ret;					\
 	})
 
+/*
+ * probe_kernel_read(): safely attempt to read from a location
+ * @dst: pointer to the buffer that shall take the data
+ * @src: address to read from
+ * @size: size of the data chunk
+ *
+ * Safely read from address @src to the buffer at @dst.  If a kernel fault
+ * happens, handle that and return -EFAULT.
+ */
+extern long probe_kernel_read(void *dst, void *src, size_t size);
+
+/*
+ * probe_kernel_write(): safely attempt to write to a location
+ * @dst: address to write to
+ * @src: pointer to the data that shall be written
+ * @size: size of the data chunk
+ *
+ * Safely write to address @dst from the buffer at @src.  If a kernel fault
+ * happens, handle that and return -EFAULT.
+ */
+extern long probe_kernel_write(void *dst, void *src, size_t size);
+
 #endif		/* __LINUX_UACCESS_H__ */
diff --git a/kernel/Makefile b/kernel/Makefile
index 6c584c5..05c8003 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -53,6 +53,7 @@ obj-$(CONFIG_AUDIT) += audit.o auditfilter.o
 obj-$(CONFIG_AUDITSYSCALL) += auditsc.o
 obj-$(CONFIG_AUDIT_TREE) += audit_tree.o
 obj-$(CONFIG_KPROBES) += kprobes.o
+obj-$(CONFIG_KGDB) += kgdb.o
 obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
 obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
 obj-$(CONFIG_SECCOMP) += seccomp.o
diff --git a/kernel/kgdb.c b/kernel/kgdb.c
new file mode 100644
index 0000000..21d30cf
--- /dev/null
+++ b/kernel/kgdb.c
@@ -0,0 +1,1675 @@
+/*
+ * KGDB stub.
+ *
+ * Maintainer: Jason Wessel <jason.wessel@windriver.com>
+ *
+ * Copyright (C) 2000-2001 VERITAS Software Corporation.
+ * Copyright (C) 2002-2004 Timesys Corporation
+ * Copyright (C) 2003-2004 Amit S. Kale <amitkale@linsyssoft.com>
+ * Copyright (C) 2004 Pavel Machek <pavel@suse.cz>
+ * Copyright (C) 2004-2006 Tom Rini <trini@kernel.crashing.org>
+ * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd.
+ * Copyright (C) 2005-2008 Wind River Systems, Inc.
+ * Copyright (C) 2007 MontaVista Software, Inc.
+ * Copyright (C) 2008 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ * Contributors at various stages not listed above:
+ *  Jason Wessel ( jason.wessel@windriver.com )
+ *  George Anzinger <george@mvista.com>
+ *  Anurekh Saxena (anurekh.saxena@timesys.com)
+ *  Lake Stevens Instrument Division (Glenn Engel)
+ *  Jim Kingdon, Cygnus Support.
+ *
+ * Original KGDB stub: David Grothe <dave@gcom.com>,
+ * Tigran Aivazian <tigran@sco.com>
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2. This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+#include <linux/pid_namespace.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/console.h>
+#include <linux/threads.h>
+#include <linux/uaccess.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/ptrace.h>
+#include <linux/reboot.h>
+#include <linux/string.h>
+#include <linux/delay.h>
+#include <linux/sched.h>
+#include <linux/sysrq.h>
+#include <linux/init.h>
+#include <linux/kgdb.h>
+#include <linux/pid.h>
+#include <linux/smp.h>
+#include <linux/mm.h>
+
+#include <asm/cacheflush.h>
+#include <asm/byteorder.h>
+#include <asm/atomic.h>
+#include <asm/system.h>
+
+static int kgdb_break_asap;
+
+struct kgdb_state {
+	int			ex_vector;
+	int			signo;
+	int			err_code;
+	int			cpu;
+	int			pass_exception;
+	long			threadid;
+	long			kgdb_usethreadid;
+	struct pt_regs		*linux_regs;
+};
+
+static struct debuggerinfo_struct {
+	void			*debuggerinfo;
+	struct task_struct	*task;
+} kgdb_info[NR_CPUS];
+
+/**
+ * kgdb_connected - Is a host GDB connected to us?
+ */
+int				kgdb_connected;
+EXPORT_SYMBOL_GPL(kgdb_connected);
+
+/* All the KGDB handlers are installed */
+static int			kgdb_io_module_registered;
+
+/* Guard for recursive entry */
+static int			exception_level;
+
+static struct kgdb_io		*kgdb_io_ops;
+static DEFINE_SPINLOCK(kgdb_registration_lock);
+
+/* kgdb console driver is loaded */
+static int kgdb_con_registered;
+/* determine if kgdb console output should be used */
+static int kgdb_use_con;
+
+static int __init opt_kgdb_con(char *str)
+{
+	kgdb_use_con = 1;
+	return 0;
+}
+
+early_param("kgdbcon", opt_kgdb_con);
+
+module_param(kgdb_use_con, int, 0644);
+
+/*
+ * Holds information about breakpoints in a kernel. These breakpoints are
+ * added and removed by gdb.
+ */
+static struct kgdb_bkpt		kgdb_break[KGDB_MAX_BREAKPOINTS] = {
+	[0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED }
+};
+
+/*
+ * The CPU# of the active CPU, or -1 if none:
+ */
+atomic_t			kgdb_active = ATOMIC_INIT(-1);
+
+/*
+ * We use NR_CPUs not PERCPU, in case kgdb is used to debug early
+ * bootup code (which might not have percpu set up yet):
+ */
+static atomic_t			passive_cpu_wait[NR_CPUS];
+static atomic_t			cpu_in_kgdb[NR_CPUS];
+atomic_t			kgdb_setting_breakpoint;
+
+struct task_struct		*kgdb_usethread;
+struct task_struct		*kgdb_contthread;
+
+int				kgdb_single_step;
+
+/* Our I/O buffers. */
+static char			remcom_in_buffer[BUFMAX];
+static char			remcom_out_buffer[BUFMAX];
+
+/* Storage for the registers, in GDB format. */
+static unsigned long		gdb_regs[(NUMREGBYTES +
+					sizeof(unsigned long) - 1) /
+					sizeof(unsigned long)];
+
+/* to keep track of the CPU which is doing the single stepping*/
+atomic_t			kgdb_cpu_doing_single_step = ATOMIC_INIT(-1);
+
+/*
+ * Finally, some KGDB code :-)
+ */
+
+/*
+ * Weak aliases for breakpoint management,
+ * can be overriden by architectures when needed:
+ */
+int __weak kgdb_validate_break_address(unsigned long addr)
+{
+	char tmp_variable[BREAK_INSTR_SIZE];
+
+	return probe_kernel_read(tmp_variable, (char *)addr, BREAK_INSTR_SIZE);
+}
+
+int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr)
+{
+	int err;
+
+	err = probe_kernel_read(saved_instr, (char *)addr, BREAK_INSTR_SIZE);
+	if (err)
+		return err;
+
+	return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr,
+				  BREAK_INSTR_SIZE);
+}
+
+int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle)
+{
+	return probe_kernel_write((char *)addr,
+				  (char *)bundle, BREAK_INSTR_SIZE);
+}
+
+unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs)
+{
+	return instruction_pointer(regs);
+}
+
+int __weak kgdb_arch_init(void)
+{
+	return 0;
+}
+
+/**
+ *	kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
+ *	@regs: Current &struct pt_regs.
+ *
+ *	This function will be called if the particular architecture must
+ *	disable hardware debugging while it is processing gdb packets or
+ *	handling exception.
+ */
+void __weak kgdb_disable_hw_debug(struct pt_regs *regs)
+{
+}
+
+/*
+ * GDB remote protocol parser:
+ */
+
+static const char	hexchars[] = "0123456789abcdef";
+
+static int hex(char ch)
+{
+	if ((ch >= 'a') && (ch <= 'f'))
+		return ch - 'a' + 10;
+	if ((ch >= '0') && (ch <= '9'))
+		return ch - '0';
+	if ((ch >= 'A') && (ch <= 'F'))
+		return ch - 'A' + 10;
+	return -1;
+}
+
+/* scan for the sequence $<data>#<checksum> */
+static void get_packet(char *buffer)
+{
+	unsigned char checksum;
+	unsigned char xmitcsum;
+	int count;
+	char ch;
+
+	do {
+		/*
+		 * Spin and wait around for the start character, ignore all
+		 * other characters:
+		 */
+		while ((ch = (kgdb_io_ops->read_char())) != '$')
+			/* nothing */;
+
+		kgdb_connected = 1;
+		checksum = 0;
+		xmitcsum = -1;
+
+		count = 0;
+
+		/*
+		 * now, read until a # or end of buffer is found:
+		 */
+		while (count < (BUFMAX - 1)) {
+			ch = kgdb_io_ops->read_char();
+			if (ch == '#')
+				break;
+			checksum = checksum + ch;
+			buffer[count] = ch;
+			count = count + 1;
+		}
+		buffer[count] = 0;
+
+		if (ch == '#') {
+			xmitcsum = hex(kgdb_io_ops->read_char()) << 4;
+			xmitcsum += hex(kgdb_io_ops->read_char());
+
+			if (checksum != xmitcsum)
+				/* failed checksum */
+				kgdb_io_ops->write_char('-');
+			else
+				/* successful transfer */
+				kgdb_io_ops->write_char('+');
+			if (kgdb_io_ops->flush)
+				kgdb_io_ops->flush();
+		}
+	} while (checksum != xmitcsum);
+}
+
+/*
+ * Send the packet in buffer.
+ * Check for gdb connection if asked for.
+ */
+static void put_packet(char *buffer)
+{
+	unsigned char checksum;
+	int count;
+	char ch;
+
+	/*
+	 * $<packet info>#<checksum>.
+	 */
+	while (1) {
+		kgdb_io_ops->write_char('$');
+		checksum = 0;
+		count = 0;
+
+		while ((ch = buffer[count])) {
+			kgdb_io_ops->write_char(ch);
+			checksum += ch;
+			count++;
+		}
+
+		kgdb_io_ops->write_char('#');
+		kgdb_io_ops->write_char(hexchars[checksum >> 4]);
+		kgdb_io_ops->write_char(hexchars[checksum & 0xf]);
+		if (kgdb_io_ops->flush)
+			kgdb_io_ops->flush();
+
+		/* Now see what we get in reply. */
+		ch = kgdb_io_ops->read_char();
+
+		if (ch == 3)
+			ch = kgdb_io_ops->read_char();
+
+		/* If we get an ACK, we are done. */
+		if (ch == '+')
+			return;
+
+		/*
+		 * If we get the start of another packet, this means
+		 * that GDB is attempting to reconnect.  We will NAK
+		 * the packet being sent, and stop trying to send this
+		 * packet.
+		 */
+		if (ch == '$') {
+			kgdb_io_ops->write_char('-');
+			if (kgdb_io_ops->flush)
+				kgdb_io_ops->flush();
+			return;
+		}
+	}
+}
+
+static char *pack_hex_byte(char *pkt, u8 byte)
+{
+	*pkt++ = hexchars[byte >> 4];
+	*pkt++ = hexchars[byte & 0xf];
+
+	return pkt;
+}
+
+/*
+ * Convert the memory pointed to by mem into hex, placing result in buf.
+ * Return a pointer to the last char put in buf (null). May return an error.
+ */
+int kgdb_mem2hex(char *mem, char *buf, int count)
+{
+	char *tmp;
+	int err;
+
+	/*
+	 * We use the upper half of buf as an intermediate buffer for the
+	 * raw memory copy.  Hex conversion will work against this one.
+	 */
+	tmp = buf + count;
+
+	err = probe_kernel_read(tmp, mem, count);
+	if (!err) {
+		while (count > 0) {
+			buf = pack_hex_byte(buf, *tmp);
+			tmp++;
+			count--;
+		}
+
+		*buf = 0;
+	}
+
+	return err;
+}
+
+/*
+ * Copy the binary array pointed to by buf into mem.  Fix $, #, and
+ * 0x7d escaped with 0x7d.  Return a pointer to the character after
+ * the last byte written.
+ */
+static int kgdb_ebin2mem(char *buf, char *mem, int count)
+{
+	int err = 0;
+	char c;
+
+	while (count-- > 0) {
+		c = *buf++;
+		if (c == 0x7d)
+			c = *buf++ ^ 0x20;
+
+		err = probe_kernel_write(mem, &c, 1);
+		if (err)
+			break;
+
+		mem++;
+	}
+
+	return err;
+}
+
+/*
+ * Convert the hex array pointed to by buf into binary to be placed in mem.
+ * Return a pointer to the character AFTER the last byte written.
+ * May return an error.
+ */
+int kgdb_hex2mem(char *buf, char *mem, int count)
+{
+	char *tmp_raw;
+	char *tmp_hex;
+
+	/*
+	 * We use the upper half of buf as an intermediate buffer for the
+	 * raw memory that is converted from hex.
+	 */
+	tmp_raw = buf + count * 2;
+
+	tmp_hex = tmp_raw - 1;
+	while (tmp_hex >= buf) {
+		tmp_raw--;
+		*tmp_raw = hex(*tmp_hex--);
+		*tmp_raw |= hex(*tmp_hex--) << 4;
+	}
+
+	return probe_kernel_write(mem, tmp_raw, count);
+}
+
+/*
+ * While we find nice hex chars, build a long_val.
+ * Return number of chars processed.
+ */
+int kgdb_hex2long(char **ptr, long *long_val)
+{
+	int hex_val;
+	int num = 0;
+
+	*long_val = 0;
+
+	while (**ptr) {
+		hex_val = hex(**ptr);
+		if (hex_val < 0)
+			break;
+
+		*long_val = (*long_val << 4) | hex_val;
+		num++;
+		(*ptr)++;
+	}
+
+	return num;
+}
+
+/* Write memory due to an 'M' or 'X' packet. */
+static int write_mem_msg(int binary)
+{
+	char *ptr = &remcom_in_buffer[1];
+	unsigned long addr;
+	unsigned long length;
+	int err;
+
+	if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' &&
+	    kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') {
+		if (binary)
+			err = kgdb_ebin2mem(ptr, (char *)addr, length);
+		else
+			err = kgdb_hex2mem(ptr, (char *)addr, length);
+		if (err)
+			return err;
+		if (CACHE_FLUSH_IS_SAFE)
+			flush_icache_range(addr, addr + length + 1);
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static void error_packet(char *pkt, int error)
+{
+	error = -error;
+	pkt[0] = 'E';
+	pkt[1] = hexchars[(error / 10)];
+	pkt[2] = hexchars[(error % 10)];
+	pkt[3] = '\0';
+}
+
+/*
+ * Thread ID accessors. We represent a flat TID space to GDB, where
+ * the per CPU idle threads (which under Linux all have PID 0) are
+ * remapped to negative TIDs.
+ */
+
+#define BUF_THREAD_ID_SIZE	16
+
+static char *pack_threadid(char *pkt, unsigned char *id)
+{
+	char *limit;
+
+	limit = pkt + BUF_THREAD_ID_SIZE;
+	while (pkt < limit)
+		pkt = pack_hex_byte(pkt, *id++);
+
+	return pkt;
+}
+
+static void int_to_threadref(unsigned char *id, int value)
+{
+	unsigned char *scan;
+	int i = 4;
+
+	scan = (unsigned char *)id;
+	while (i--)
+		*scan++ = 0;
+	*scan++ = (value >> 24) & 0xff;
+	*scan++ = (value >> 16) & 0xff;
+	*scan++ = (value >> 8) & 0xff;
+	*scan++ = (value & 0xff);
+}
+
+static struct task_struct *getthread(struct pt_regs *regs, int tid)
+{
+	/*
+	 * Non-positive TIDs are remapped idle tasks:
+	 */
+	if (tid <= 0)
+		return idle_task(-tid);
+
+	/*
+	 * find_task_by_pid() does not take the tasklist lock anymore
+	 * but is nicely RCU locked - hence is a pretty resilient
+	 * thing to use:
+	 */
+	return find_task_by_pid(tid);
+}
+
+/*
+ * CPU debug state control:
+ */
+
+#ifdef CONFIG_SMP
+static void kgdb_wait(struct pt_regs *regs)
+{
+	unsigned long flags;
+	int cpu;
+
+	local_irq_save(flags);
+	cpu = raw_smp_processor_id();
+	kgdb_info[cpu].debuggerinfo = regs;
+	kgdb_info[cpu].task = current;
+	/*
+	 * Make sure the above info reaches the primary CPU before
+	 * our cpu_in_kgdb[] flag setting does:
+	 */
+	smp_wmb();
+	atomic_set(&cpu_in_kgdb[cpu], 1);
+
+	/*
+	 * The primary CPU must be active to enter here, but this is
+	 * guard in case the primary CPU had not been selected if
+	 * this was an entry via nmi.
+	 */
+	while (atomic_read(&kgdb_active) == -1)
+		cpu_relax();
+
+	/* Wait till primary CPU goes completely into the debugger. */
+	while (!atomic_read(&cpu_in_kgdb[atomic_read(&kgdb_active)]))
+		cpu_relax();
+
+	/* Wait till primary CPU is done with debugging */
+	while (atomic_read(&passive_cpu_wait[cpu]))
+		cpu_relax();
+
+	kgdb_info[cpu].debuggerinfo = NULL;
+	kgdb_info[cpu].task = NULL;
+
+	/* fix up hardware debug registers on local cpu */
+	if (arch_kgdb_ops.correct_hw_break)
+		arch_kgdb_ops.correct_hw_break();
+
+	/* Signal the primary CPU that we are done: */
+	atomic_set(&cpu_in_kgdb[cpu], 0);
+	local_irq_restore(flags);
+}
+#endif
+
+/*
+ * Some architectures need cache flushes when we set/clear a
+ * breakpoint:
+ */
+static void kgdb_flush_swbreak_addr(unsigned long addr)
+{
+	if (!CACHE_FLUSH_IS_SAFE)
+		return;
+
+	if (current->mm) {
+		flush_cache_range(current->mm->mmap_cache,
+				  addr, addr + BREAK_INSTR_SIZE);
+	} else {
+		flush_icache_range(addr, addr + BREAK_INSTR_SIZE);
+	}
+}
+
+/*
+ * SW breakpoint management:
+ */
+static int kgdb_activate_sw_breakpoints(void)
+{
+	unsigned long addr;
+	int error = 0;
+	int i;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (kgdb_break[i].state != BP_SET)
+			continue;
+
+		addr = kgdb_break[i].bpt_addr;
+		error = kgdb_arch_set_breakpoint(addr,
+				kgdb_break[i].saved_instr);
+		if (error)
+			return error;
+
+		kgdb_flush_swbreak_addr(addr);
+		kgdb_break[i].state = BP_ACTIVE;
+	}
+	return 0;
+}
+
+static int kgdb_set_sw_break(unsigned long addr)
+{
+	int err = kgdb_validate_break_address(addr);
+	int breakno = -1;
+	int i;
+
+	if (err)
+		return err;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if ((kgdb_break[i].state == BP_SET) &&
+					(kgdb_break[i].bpt_addr == addr))
+			return -EEXIST;
+	}
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (kgdb_break[i].state == BP_REMOVED &&
+					kgdb_break[i].bpt_addr == addr) {
+			breakno = i;
+			break;
+		}
+	}
+
+	if (breakno == -1) {
+		for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+			if (kgdb_break[i].state == BP_UNDEFINED) {
+				breakno = i;
+				break;
+			}
+		}
+	}
+
+	if (breakno == -1)
+		return -E2BIG;
+
+	kgdb_break[breakno].state = BP_SET;
+	kgdb_break[breakno].type = BP_BREAKPOINT;
+	kgdb_break[breakno].bpt_addr = addr;
+
+	return 0;
+}
+
+static int kgdb_deactivate_sw_breakpoints(void)
+{
+	unsigned long addr;
+	int error = 0;
+	int i;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (kgdb_break[i].state != BP_ACTIVE)
+			continue;
+		addr = kgdb_break[i].bpt_addr;
+		error = kgdb_arch_remove_breakpoint(addr,
+					kgdb_break[i].saved_instr);
+		if (error)
+			return error;
+
+		kgdb_flush_swbreak_addr(addr);
+		kgdb_break[i].state = BP_SET;
+	}
+	return 0;
+}
+
+static int kgdb_remove_sw_break(unsigned long addr)
+{
+	int i;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if ((kgdb_break[i].state == BP_SET) &&
+				(kgdb_break[i].bpt_addr == addr)) {
+			kgdb_break[i].state = BP_REMOVED;
+			return 0;
+		}
+	}
+	return -ENOENT;
+}
+
+int kgdb_isremovedbreak(unsigned long addr)
+{
+	int i;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if ((kgdb_break[i].state == BP_REMOVED) &&
+					(kgdb_break[i].bpt_addr == addr))
+			return 1;
+	}
+	return 0;
+}
+
+int remove_all_break(void)
+{
+	unsigned long addr;
+	int error;
+	int i;
+
+	/* Clear memory breakpoints. */
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (kgdb_break[i].state != BP_SET)
+			continue;
+		addr = kgdb_break[i].bpt_addr;
+		error = kgdb_arch_remove_breakpoint(addr,
+				kgdb_break[i].saved_instr);
+		if (error)
+			return error;
+		kgdb_break[i].state = BP_REMOVED;
+	}
+
+	/* Clear hardware breakpoints. */
+	if (arch_kgdb_ops.remove_all_hw_break)
+		arch_kgdb_ops.remove_all_hw_break();
+
+	return 0;
+}
+
+/*
+ * Remap normal tasks to their real PID, idle tasks to -1 ... -NR_CPUs:
+ */
+static inline int shadow_pid(int realpid)
+{
+	if (realpid)
+		return realpid;
+
+	return -1-raw_smp_processor_id();
+}
+
+static char gdbmsgbuf[BUFMAX + 1];
+
+static void kgdb_msg_write(const char *s, int len)
+{
+	char *bufptr;
+	int wcount;
+	int i;
+
+	/* 'O'utput */
+	gdbmsgbuf[0] = 'O';
+
+	/* Fill and send buffers... */
+	while (len > 0) {
+		bufptr = gdbmsgbuf + 1;
+
+		/* Calculate how many this time */
+		if ((len << 1) > (BUFMAX - 2))
+			wcount = (BUFMAX - 2) >> 1;
+		else
+			wcount = len;
+
+		/* Pack in hex chars */
+		for (i = 0; i < wcount; i++)
+			bufptr = pack_hex_byte(bufptr, s[i]);
+		*bufptr = '\0';
+
+		/* Move up */
+		s += wcount;
+		len -= wcount;
+
+		/* Write packet */
+		put_packet(gdbmsgbuf);
+	}
+}
+
+/*
+ * Return true if there is a valid kgdb I/O module.  Also if no
+ * debugger is attached a message can be printed to the console about
+ * waiting for the debugger to attach.
+ *
+ * The print_wait argument is only to be true when called from inside
+ * the core kgdb_handle_exception, because it will wait for the
+ * debugger to attach.
+ */
+static int kgdb_io_ready(int print_wait)
+{
+	if (!kgdb_io_ops)
+		return 0;
+	if (kgdb_connected)
+		return 1;
+	if (atomic_read(&kgdb_setting_breakpoint))
+		return 1;
+	if (print_wait)
+		printk(KERN_CRIT "KGDB: Waiting for remote debugger\n");
+	return 1;
+}
+
+/*
+ * All the functions that start with gdb_cmd are the various
+ * operations to implement the handlers for the gdbserial protocol
+ * where KGDB is communicating with an external debugger
+ */
+
+/* Handle the '?' status packets */
+static void gdb_cmd_status(struct kgdb_state *ks)
+{
+	/*
+	 * We know that this packet is only sent
+	 * during initial connect.  So to be safe,
+	 * we clear out our breakpoints now in case
+	 * GDB is reconnecting.
+	 */
+	remove_all_break();
+
+	remcom_out_buffer[0] = 'S';
+	pack_hex_byte(&remcom_out_buffer[1], ks->signo);
+}
+
+/* Handle the 'g' get registers request */
+static void gdb_cmd_getregs(struct kgdb_state *ks)
+{
+	struct task_struct *thread;
+	void *local_debuggerinfo;
+	int i;
+
+	thread = kgdb_usethread;
+	if (!thread) {
+		thread = kgdb_info[ks->cpu].task;
+		local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo;
+	} else {
+		local_debuggerinfo = NULL;
+		for (i = 0; i < NR_CPUS; i++) {
+			/*
+			 * Try to find the task on some other
+			 * or possibly this node if we do not
+			 * find the matching task then we try
+			 * to approximate the results.
+			 */
+			if (thread == kgdb_info[i].task)
+				local_debuggerinfo = kgdb_info[i].debuggerinfo;
+		}
+	}
+
+	/*
+	 * All threads that don't have debuggerinfo should be
+	 * in __schedule() sleeping, since all other CPUs
+	 * are in kgdb_wait, and thus have debuggerinfo.
+	 */
+	if (local_debuggerinfo) {
+		pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo);
+	} else {
+		/*
+		 * Pull stuff saved during switch_to; nothing
+		 * else is accessible (or even particularly
+		 * relevant).
+		 *
+		 * This should be enough for a stack trace.
+		 */
+		sleeping_thread_to_gdb_regs(gdb_regs, thread);
+	}
+	kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES);
+}
+
+/* Handle the 'G' set registers request */
+static void gdb_cmd_setregs(struct kgdb_state *ks)
+{
+	kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES);
+
+	if (kgdb_usethread && kgdb_usethread != current) {
+		error_packet(remcom_out_buffer, -EINVAL);
+	} else {
+		gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs);
+		strcpy(remcom_out_buffer, "OK");
+	}
+}
+
+/* Handle the 'm' memory read bytes */
+static void gdb_cmd_memread(struct kgdb_state *ks)
+{
+	char *ptr = &remcom_in_buffer[1];
+	unsigned long length;
+	unsigned long addr;
+	int err;
+
+	if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' &&
+					kgdb_hex2long(&ptr, &length) > 0) {
+		err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length);
+		if (err)
+			error_packet(remcom_out_buffer, err);
+	} else {
+		error_packet(remcom_out_buffer, -EINVAL);
+	}
+}
+
+/* Handle the 'M' memory write bytes */
+static void gdb_cmd_memwrite(struct kgdb_state *ks)
+{
+	int err = write_mem_msg(0);
+
+	if (err)
+		error_packet(remcom_out_buffer, err);
+	else
+		strcpy(remcom_out_buffer, "OK");
+}
+
+/* Handle the 'X' memory binary write bytes */
+static void gdb_cmd_binwrite(struct kgdb_state *ks)
+{
+	int err = write_mem_msg(1);
+
+	if (err)
+		error_packet(remcom_out_buffer, err);
+	else
+		strcpy(remcom_out_buffer, "OK");
+}
+
+/* Handle the 'D' or 'k', detach or kill packets */
+static void gdb_cmd_detachkill(struct kgdb_state *ks)
+{
+	int error;
+
+	/* The detach case */
+	if (remcom_in_buffer[0] == 'D') {
+		error = remove_all_break();
+		if (error < 0) {
+			error_packet(remcom_out_buffer, error);
+		} else {
+			strcpy(remcom_out_buffer, "OK");
+			kgdb_connected = 0;
+		}
+		put_packet(remcom_out_buffer);
+	} else {
+		/*
+		 * Assume the kill case, with no exit code checking,
+		 * trying to force detach the debugger:
+		 */
+		remove_all_break();
+		kgdb_connected = 0;
+	}
+}
+
+/* Handle the 'R' reboot packets */
+static int gdb_cmd_reboot(struct kgdb_state *ks)
+{
+	/* For now, only honor R0 */
+	if (strcmp(remcom_in_buffer, "R0") == 0) {
+		printk(KERN_CRIT "Executing emergency reboot\n");
+		strcpy(remcom_out_buffer, "OK");
+		put_packet(remcom_out_buffer);
+
+		/*
+		 * Execution should not return from
+		 * machine_emergency_restart()
+		 */
+		machine_emergency_restart();
+		kgdb_connected = 0;
+
+		return 1;
+	}
+	return 0;
+}
+
+/* Handle the 'q' query packets */
+static void gdb_cmd_query(struct kgdb_state *ks)
+{
+	struct task_struct *thread;
+	unsigned char thref[8];
+	char *ptr;
+	int i;
+
+	switch (remcom_in_buffer[1]) {
+	case 's':
+	case 'f':
+		if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) {
+			error_packet(remcom_out_buffer, -EINVAL);
+			break;
+		}
+
+		if (remcom_in_buffer[1] == 'f')
+			ks->threadid = 1;
+
+		remcom_out_buffer[0] = 'm';
+		ptr = remcom_out_buffer + 1;
+
+		for (i = 0; i < 17; ks->threadid++) {
+			thread = getthread(ks->linux_regs, ks->threadid);
+			if (thread) {
+				int_to_threadref(thref, ks->threadid);
+				pack_threadid(ptr, thref);
+				ptr += BUF_THREAD_ID_SIZE;
+				*(ptr++) = ',';
+				i++;
+			}
+		}
+		*(--ptr) = '\0';
+		break;
+
+	case 'C':
+		/* Current thread id */
+		strcpy(remcom_out_buffer, "QC");
+		ks->threadid = shadow_pid(current->pid);
+		int_to_threadref(thref, ks->threadid);
+		pack_threadid(remcom_out_buffer + 2, thref);
+		break;
+	case 'T':
+		if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) {
+			error_packet(remcom_out_buffer, -EINVAL);
+			break;
+		}
+		ks->threadid = 0;
+		ptr = remcom_in_buffer + 17;
+		kgdb_hex2long(&ptr, &ks->threadid);
+		if (!getthread(ks->linux_regs, ks->threadid)) {
+			error_packet(remcom_out_buffer, -EINVAL);
+			break;
+		}
+		if (ks->threadid > 0) {
+			kgdb_mem2hex(getthread(ks->linux_regs,
+					ks->threadid)->comm,
+					remcom_out_buffer, 16);
+		} else {
+			static char tmpstr[23 + BUF_THREAD_ID_SIZE];
+
+			sprintf(tmpstr, "Shadow task %d for pid 0",
+					(int)(-ks->threadid-1));
+			kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr));
+		}
+		break;
+	}
+}
+
+/* Handle the 'H' task query packets */
+static void gdb_cmd_task(struct kgdb_state *ks)
+{
+	struct task_struct *thread;
+	char *ptr;
+
+	switch (remcom_in_buffer[1]) {
+	case 'g':
+		ptr = &remcom_in_buffer[2];
+		kgdb_hex2long(&ptr, &ks->threadid);
+		thread = getthread(ks->linux_regs, ks->threadid);
+		if (!thread && ks->threadid > 0) {
+			error_packet(remcom_out_buffer, -EINVAL);
+			break;
+		}
+		kgdb_usethread = thread;
+		ks->kgdb_usethreadid = ks->threadid;
+		strcpy(remcom_out_buffer, "OK");
+		break;
+	case 'c':
+		ptr = &remcom_in_buffer[2];
+		kgdb_hex2long(&ptr, &ks->threadid);
+		if (!ks->threadid) {
+			kgdb_contthread = NULL;
+		} else {
+			thread = getthread(ks->linux_regs, ks->threadid);
+			if (!thread && ks->threadid > 0) {
+				error_packet(remcom_out_buffer, -EINVAL);
+				break;
+			}
+			kgdb_contthread = thread;
+		}
+		strcpy(remcom_out_buffer, "OK");
+		break;
+	}
+}
+
+/* Handle the 'T' thread query packets */
+static void gdb_cmd_thread(struct kgdb_state *ks)
+{
+	char *ptr = &remcom_in_buffer[1];
+	struct task_struct *thread;
+
+	kgdb_hex2long(&ptr, &ks->threadid);
+	thread = getthread(ks->linux_regs, ks->threadid);
+	if (thread)
+		strcpy(remcom_out_buffer, "OK");
+	else
+		error_packet(remcom_out_buffer, -EINVAL);
+}
+
+/* Handle the 'z' or 'Z' breakpoint remove or set packets */
+static void gdb_cmd_break(struct kgdb_state *ks)
+{
+	/*
+	 * Since GDB-5.3, it's been drafted that '0' is a software
+	 * breakpoint, '1' is a hardware breakpoint, so let's do that.
+	 */
+	char *bpt_type = &remcom_in_buffer[1];
+	char *ptr = &remcom_in_buffer[2];
+	unsigned long addr;
+	unsigned long length;
+	int error = 0;
+
+	if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') {
+		/* Unsupported */
+		if (*bpt_type > '4')
+			return;
+	} else {
+		if (*bpt_type != '0' && *bpt_type != '1')
+			/* Unsupported. */
+			return;
+	}
+
+	/*
+	 * Test if this is a hardware breakpoint, and
+	 * if we support it:
+	 */
+	if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT))
+		/* Unsupported. */
+		return;
+
+	if (*(ptr++) != ',') {
+		error_packet(remcom_out_buffer, -EINVAL);
+		return;
+	}
+	if (!kgdb_hex2long(&ptr, &addr)) {
+		error_packet(remcom_out_buffer, -EINVAL);
+		return;
+	}
+	if (*(ptr++) != ',' ||
+		!kgdb_hex2long(&ptr, &length)) {
+		error_packet(remcom_out_buffer, -EINVAL);
+		return;
+	}
+
+	if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0')
+		error = kgdb_set_sw_break(addr);
+	else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0')
+		error = kgdb_remove_sw_break(addr);
+	else if (remcom_in_buffer[0] == 'Z')
+		error = arch_kgdb_ops.set_hw_breakpoint(addr,
+			(int)length, *bpt_type);
+	else if (remcom_in_buffer[0] == 'z')
+		error = arch_kgdb_ops.remove_hw_breakpoint(addr,
+			(int) length, *bpt_type);
+
+	if (error == 0)
+		strcpy(remcom_out_buffer, "OK");
+	else
+		error_packet(remcom_out_buffer, error);
+}
+
+/* Handle the 'C' signal / exception passing packets */
+static int gdb_cmd_exception_pass(struct kgdb_state *ks)
+{
+	/* C09 == pass exception
+	 * C15 == detach kgdb, pass exception
+	 */
+	if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') {
+
+		ks->pass_exception = 1;
+		remcom_in_buffer[0] = 'c';
+
+	} else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') {
+
+		ks->pass_exception = 1;
+		remcom_in_buffer[0] = 'D';
+		remove_all_break();
+		kgdb_connected = 0;
+		return 1;
+
+	} else {
+		error_packet(remcom_out_buffer, -EINVAL);
+		return 0;
+	}
+
+	/* Indicate fall through */
+	return -1;
+}
+
+/*
+ * This function performs all gdbserial command procesing
+ */
+static int gdb_serial_stub(struct kgdb_state *ks)
+{
+	int error = 0;
+	int tmp;
+
+	/* Clear the out buffer. */
+	memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
+
+	if (kgdb_connected) {
+		unsigned char thref[8];
+		char *ptr;
+
+		/* Reply to host that an exception has occurred */
+		ptr = remcom_out_buffer;
+		*ptr++ = 'T';
+		ptr = pack_hex_byte(ptr, ks->signo);
+		ptr += strlen(strcpy(ptr, "thread:"));
+		int_to_threadref(thref, shadow_pid(current->pid));
+		ptr = pack_threadid(ptr, thref);
+		*ptr++ = ';';
+		put_packet(remcom_out_buffer);
+	}
+
+	kgdb_usethread = kgdb_info[ks->cpu].task;
+	ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid);
+	ks->pass_exception = 0;
+
+	while (1) {
+		error = 0;
+
+		/* Clear the out buffer. */
+		memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
+
+		get_packet(remcom_in_buffer);
+
+		switch (remcom_in_buffer[0]) {
+		case '?': /* gdbserial status */
+			gdb_cmd_status(ks);
+			break;
+		case 'g': /* return the value of the CPU registers */
+			gdb_cmd_getregs(ks);
+			break;
+		case 'G': /* set the value of the CPU registers - return OK */
+			gdb_cmd_setregs(ks);
+			break;
+		case 'm': /* mAA..AA,LLLL  Read LLLL bytes at address AA..AA */
+			gdb_cmd_memread(ks);
+			break;
+		case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
+			gdb_cmd_memwrite(ks);
+			break;
+		case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
+			gdb_cmd_binwrite(ks);
+			break;
+			/* kill or detach. KGDB should treat this like a
+			 * continue.
+			 */
+		case 'D': /* Debugger detach */
+		case 'k': /* Debugger detach via kill */
+			gdb_cmd_detachkill(ks);
+			goto default_handle;
+		case 'R': /* Reboot */
+			if (gdb_cmd_reboot(ks))
+				goto default_handle;
+			break;
+		case 'q': /* query command */
+			gdb_cmd_query(ks);
+			break;
+		case 'H': /* task related */
+			gdb_cmd_task(ks);
+			break;
+		case 'T': /* Query thread status */
+			gdb_cmd_thread(ks);
+			break;
+		case 'z': /* Break point remove */
+		case 'Z': /* Break point set */
+			gdb_cmd_break(ks);
+			break;
+		case 'C': /* Exception passing */
+			tmp = gdb_cmd_exception_pass(ks);
+			if (tmp > 0)
+				goto default_handle;
+			if (tmp == 0)
+				break;
+			/* Fall through on tmp < 0 */
+		case 'c': /* Continue packet */
+		case 's': /* Single step packet */
+			if (kgdb_contthread && kgdb_contthread != current) {
+				/* Can't switch threads in kgdb */
+				error_packet(remcom_out_buffer, -EINVAL);
+				break;
+			}
+			kgdb_activate_sw_breakpoints();
+			/* Fall through to default processing */
+		default:
+default_handle:
+			error = kgdb_arch_handle_exception(ks->ex_vector,
+						ks->signo,
+						ks->err_code,
+						remcom_in_buffer,
+						remcom_out_buffer,
+						ks->linux_regs);
+			/*
+			 * Leave cmd processing on error, detach,
+			 * kill, continue, or single step.
+			 */
+			if (error >= 0 || remcom_in_buffer[0] == 'D' ||
+			    remcom_in_buffer[0] == 'k') {
+				error = 0;
+				goto kgdb_exit;
+			}
+
+		}
+
+		/* reply to the request */
+		put_packet(remcom_out_buffer);
+	}
+
+kgdb_exit:
+	if (ks->pass_exception)
+		error = 1;
+	return error;
+}
+
+static int kgdb_reenter_check(struct kgdb_state *ks)
+{
+	unsigned long addr;
+
+	if (atomic_read(&kgdb_active) != raw_smp_processor_id())
+		return 0;
+
+	/* Panic on recursive debugger calls: */
+	exception_level++;
+	addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
+	kgdb_deactivate_sw_breakpoints();
+
+	/*
+	 * If the break point removed ok at the place exception
+	 * occurred, try to recover and print a warning to the end
+	 * user because the user planted a breakpoint in a place that
+	 * KGDB needs in order to function.
+	 */
+	if (kgdb_remove_sw_break(addr) == 0) {
+		exception_level = 0;
+		kgdb_skipexception(ks->ex_vector, ks->linux_regs);
+		kgdb_activate_sw_breakpoints();
+		printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed\n");
+		WARN_ON_ONCE(1);
+
+		return 1;
+	}
+	remove_all_break();
+	kgdb_skipexception(ks->ex_vector, ks->linux_regs);
+
+	if (exception_level > 1) {
+		dump_stack();
+		panic("Recursive entry to debugger");
+	}
+
+	printk(KERN_CRIT "KGDB: re-enter exception: ALL breakpoints killed\n");
+	dump_stack();
+	panic("Recursive entry to debugger");
+
+	return 1;
+}
+
+/*
+ * kgdb_handle_exception() - main entry point from a kernel exception
+ *
+ * Locking hierarchy:
+ *	interface locks, if any (begin_session)
+ *	kgdb lock (kgdb_active)
+ */
+int
+kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
+{
+	struct kgdb_state kgdb_var;
+	struct kgdb_state *ks = &kgdb_var;
+	unsigned long flags;
+	int error = 0;
+	int i, cpu;
+
+	ks->cpu			= raw_smp_processor_id();
+	ks->ex_vector		= evector;
+	ks->signo		= signo;
+	ks->ex_vector		= evector;
+	ks->err_code		= ecode;
+	ks->kgdb_usethreadid	= 0;
+	ks->linux_regs		= regs;
+
+	if (kgdb_reenter_check(ks))
+		return 0; /* Ouch, double exception ! */
+
+acquirelock:
+	/*
+	 * Interrupts will be restored by the 'trap return' code, except when
+	 * single stepping.
+	 */
+	local_irq_save(flags);
+
+	cpu = raw_smp_processor_id();
+
+	/*
+	 * Acquire the kgdb_active lock:
+	 */
+	while (atomic_cmpxchg(&kgdb_active, -1, cpu) != -1)
+		cpu_relax();
+
+	/*
+	 * Do not start the debugger connection on this CPU if the last
+	 * instance of the exception handler wanted to come into the
+	 * debugger on a different CPU via a single step
+	 */
+	if (atomic_read(&kgdb_cpu_doing_single_step) != -1 &&
+	    atomic_read(&kgdb_cpu_doing_single_step) != cpu) {
+
+		atomic_set(&kgdb_active, -1);
+		local_irq_restore(flags);
+
+		goto acquirelock;
+	}
+
+	if (!kgdb_io_ready(1)) {
+		error = 1;
+		goto kgdb_restore; /* No I/O connection, so resume the system */
+	}
+
+	/*
+	 * Don't enter if we have hit a removed breakpoint.
+	 */
+	if (kgdb_skipexception(ks->ex_vector, ks->linux_regs))
+		goto kgdb_restore;
+
+	/* Call the I/O driver's pre_exception routine */
+	if (kgdb_io_ops->pre_exception)
+		kgdb_io_ops->pre_exception();
+
+	kgdb_info[ks->cpu].debuggerinfo = ks->linux_regs;
+	kgdb_info[ks->cpu].task = current;
+
+	kgdb_disable_hw_debug(ks->linux_regs);
+
+	/*
+	 * Get the passive CPU lock which will hold all the non-primary
+	 * CPU in a spin state while the debugger is active
+	 */
+	if (!kgdb_single_step || !kgdb_contthread) {
+		for (i = 0; i < NR_CPUS; i++)
+			atomic_set(&passive_cpu_wait[i], 1);
+	}
+
+#ifdef CONFIG_SMP
+	/* Signal the other CPUs to enter kgdb_wait() */
+	if (!kgdb_single_step || !kgdb_contthread)
+		kgdb_roundup_cpus(flags);
+#endif
+
+	/*
+	 * spin_lock code is good enough as a barrier so we don't
+	 * need one here:
+	 */
+	atomic_set(&cpu_in_kgdb[ks->cpu], 1);
+
+	/*
+	 * Wait for the other CPUs to be notified and be waiting for us:
+	 */
+	for_each_online_cpu(i) {
+		while (!atomic_read(&cpu_in_kgdb[i]))
+			cpu_relax();
+	}
+
+	/*
+	 * At this point the primary processor is completely
+	 * in the debugger and all secondary CPUs are quiescent
+	 */
+	kgdb_post_primary_code(ks->linux_regs, ks->ex_vector, ks->err_code);
+	kgdb_deactivate_sw_breakpoints();
+	kgdb_single_step = 0;
+	kgdb_contthread = NULL;
+	exception_level = 0;
+
+	/* Talk to debugger with gdbserial protocol */
+	error = gdb_serial_stub(ks);
+
+	/* Call the I/O driver's post_exception routine */
+	if (kgdb_io_ops->post_exception)
+		kgdb_io_ops->post_exception();
+
+	kgdb_info[ks->cpu].debuggerinfo = NULL;
+	kgdb_info[ks->cpu].task = NULL;
+	atomic_set(&cpu_in_kgdb[ks->cpu], 0);
+
+	if (!kgdb_single_step || !kgdb_contthread) {
+		for (i = NR_CPUS-1; i >= 0; i--)
+			atomic_set(&passive_cpu_wait[i], 0);
+		/*
+		 * Wait till all the CPUs have quit
+		 * from the debugger.
+		 */
+		for_each_online_cpu(i) {
+			while (atomic_read(&cpu_in_kgdb[i]))
+				cpu_relax();
+		}
+	}
+
+kgdb_restore:
+	/* Free kgdb_active */
+	atomic_set(&kgdb_active, -1);
+	local_irq_restore(flags);
+
+	return error;
+}
+
+int kgdb_nmicallback(int cpu, void *regs)
+{
+#ifdef CONFIG_SMP
+	if (!atomic_read(&cpu_in_kgdb[cpu]) &&
+			atomic_read(&kgdb_active) != cpu) {
+		kgdb_wait((struct pt_regs *)regs);
+		return 0;
+	}
+#endif
+	return 1;
+}
+
+void kgdb_console_write(struct console *co, const char *s, unsigned count)
+{
+	unsigned long flags;
+
+	/* If we're debugging, or KGDB has not connected, don't try
+	 * and print. */
+	if (!kgdb_connected || atomic_read(&kgdb_active) != -1)
+		return;
+
+	local_irq_save(flags);
+	kgdb_msg_write(s, count);
+	local_irq_restore(flags);
+}
+
+static struct console kgdbcons = {
+	.name		= "kgdb",
+	.write		= kgdb_console_write,
+	.flags		= CON_PRINTBUFFER | CON_ENABLED,
+	.index		= -1,
+};
+
+#ifdef CONFIG_MAGIC_SYSRQ
+static void sysrq_handle_gdb(int key, struct tty_struct *tty)
+{
+	if (!kgdb_io_ops) {
+		printk(KERN_CRIT "ERROR: No KGDB I/O module available\n");
+		return;
+	}
+	if (!kgdb_connected)
+		printk(KERN_CRIT "Entering KGDB\n");
+
+	kgdb_breakpoint();
+}
+
+static struct sysrq_key_op sysrq_gdb_op = {
+	.handler	= sysrq_handle_gdb,
+	.help_msg	= "Gdb",
+	.action_msg	= "GDB",
+};
+#endif
+
+static void kgdb_register_callbacks(void)
+{
+	if (!kgdb_io_module_registered) {
+		kgdb_io_module_registered = 1;
+		kgdb_arch_init();
+#ifdef CONFIG_MAGIC_SYSRQ
+		register_sysrq_key('g', &sysrq_gdb_op);
+#endif
+		if (kgdb_use_con && !kgdb_con_registered) {
+			register_console(&kgdbcons);
+			kgdb_con_registered = 1;
+		}
+	}
+}
+
+static void kgdb_unregister_callbacks(void)
+{
+	/*
+	 * When this routine is called KGDB should unregister from the
+	 * panic handler and clean up, making sure it is not handling any
+	 * break exceptions at the time.
+	 */
+	if (kgdb_io_module_registered) {
+		kgdb_io_module_registered = 0;
+		kgdb_arch_exit();
+#ifdef CONFIG_MAGIC_SYSRQ
+		unregister_sysrq_key('g', &sysrq_gdb_op);
+#endif
+		if (kgdb_con_registered) {
+			unregister_console(&kgdbcons);
+			kgdb_con_registered = 0;
+		}
+	}
+}
+
+static void kgdb_initial_breakpoint(void)
+{
+	kgdb_break_asap = 0;
+
+	printk(KERN_CRIT "kgdb: Waiting for connection from remote gdb...\n");
+	kgdb_breakpoint();
+}
+
+/**
+ *	kkgdb_register_io_module - register KGDB IO module
+ *	@new_kgdb_io_ops: the io ops vector
+ *
+ *	Register it with the KGDB core.
+ */
+int kgdb_register_io_module(struct kgdb_io *new_kgdb_io_ops)
+{
+	int err;
+
+	spin_lock(&kgdb_registration_lock);
+
+	if (kgdb_io_ops) {
+		spin_unlock(&kgdb_registration_lock);
+
+		printk(KERN_ERR "kgdb: Another I/O driver is already "
+				"registered with KGDB.\n");
+		return -EBUSY;
+	}
+
+	if (new_kgdb_io_ops->init) {
+		err = new_kgdb_io_ops->init();
+		if (err) {
+			spin_unlock(&kgdb_registration_lock);
+			return err;
+		}
+	}
+
+	kgdb_io_ops = new_kgdb_io_ops;
+
+	spin_unlock(&kgdb_registration_lock);
+
+	printk(KERN_INFO "kgdb: Registered I/O driver %s.\n",
+	       new_kgdb_io_ops->name);
+
+	/* Arm KGDB now. */
+	kgdb_register_callbacks();
+
+	if (kgdb_break_asap)
+		kgdb_initial_breakpoint();
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kgdb_register_io_module);
+
+/**
+ *	kkgdb_unregister_io_module - unregister KGDB IO module
+ *	@old_kgdb_io_ops: the io ops vector
+ *
+ *	Unregister it with the KGDB core.
+ */
+void kgdb_unregister_io_module(struct kgdb_io *old_kgdb_io_ops)
+{
+	BUG_ON(kgdb_connected);
+
+	/*
+	 * KGDB is no longer able to communicate out, so
+	 * unregister our callbacks and reset state.
+	 */
+	kgdb_unregister_callbacks();
+
+	spin_lock(&kgdb_registration_lock);
+
+	WARN_ON_ONCE(kgdb_io_ops != old_kgdb_io_ops);
+	kgdb_io_ops = NULL;
+
+	spin_unlock(&kgdb_registration_lock);
+
+	printk(KERN_INFO
+		"kgdb: Unregistered I/O driver %s, debugger disabled.\n",
+		old_kgdb_io_ops->name);
+}
+EXPORT_SYMBOL_GPL(kgdb_unregister_io_module);
+
+/**
+ * kgdb_breakpoint - generate breakpoint exception
+ *
+ * This function will generate a breakpoint exception.  It is used at the
+ * beginning of a program to sync up with a debugger and can be used
+ * otherwise as a quick means to stop program execution and "break" into
+ * the debugger.
+ */
+void kgdb_breakpoint(void)
+{
+	atomic_set(&kgdb_setting_breakpoint, 1);
+	wmb(); /* Sync point before breakpoint */
+	arch_kgdb_breakpoint();
+	wmb(); /* Sync point after breakpoint */
+	atomic_set(&kgdb_setting_breakpoint, 0);
+}
+EXPORT_SYMBOL_GPL(kgdb_breakpoint);
+
+static int __init opt_kgdb_wait(char *str)
+{
+	kgdb_break_asap = 1;
+
+	if (kgdb_io_module_registered)
+		kgdb_initial_breakpoint();
+
+	return 0;
+}
+
+early_param("kgdbwait", opt_kgdb_wait);
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index a370fe8..a904916 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -618,3 +618,5 @@ config PROVIDE_OHCI1394_DMA_INIT
 	  See Documentation/debugging-via-ohci1394.txt for more information.
 
 source "samples/Kconfig"
+
+source "lib/Kconfig.kgdb"
diff --git a/lib/Kconfig.kgdb b/lib/Kconfig.kgdb
new file mode 100644
index 0000000..9631ba3
--- /dev/null
+++ b/lib/Kconfig.kgdb
@@ -0,0 +1,27 @@
+
+menuconfig KGDB
+	bool "KGDB: kernel debugging with remote gdb"
+	select FRAME_POINTER
+	depends on HAVE_ARCH_KGDB
+	depends on DEBUG_KERNEL && EXPERIMENTAL
+	help
+	  If you say Y here, it will be possible to remotely debug the
+	  kernel using gdb.  Documentation of kernel debugger is available
+	  at http://kgdb.sourceforge.net as well as in DocBook form
+	  in Documentation/DocBook/.  If unsure, say N.
+
+config HAVE_ARCH_KGDB_SHADOW_INFO
+	bool
+
+config HAVE_ARCH_KGDB
+	bool
+
+config KGDB_SERIAL_CONSOLE
+	tristate "KGDB: use kgdb over the serial console"
+	depends on KGDB
+	select CONSOLE_POLL
+	select MAGIC_SYSRQ
+	default y
+	help
+	  Share a serial console with kgdb. Sysrq-g must be used
+	  to break in initially.
diff --git a/mm/Makefile b/mm/Makefile
index 9f117ba..fb9e7ac 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -8,7 +8,7 @@ mmu-$(CONFIG_MMU)	:= fremap.o highmem.o madvise.o memory.o mincore.o \
 			   vmalloc.o
 
 obj-y			:= bootmem.o filemap.o mempool.o oom_kill.o fadvise.o \
-			   page_alloc.o page-writeback.o pdflush.o \
+			   maccess.o page_alloc.o page-writeback.o pdflush.o \
 			   readahead.o swap.o truncate.o vmscan.o \
 			   prio_tree.o util.o mmzone.o vmstat.o backing-dev.o \
 			   page_isolation.o $(mmu-y)
diff --git a/mm/maccess.c b/mm/maccess.c
new file mode 100644
index 0000000..24f81b9
--- /dev/null
+++ b/mm/maccess.c
@@ -0,0 +1,49 @@
+/*
+ * Access kernel memory without faulting.
+ */
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+
+/**
+ * probe_kernel_read(): safely attempt to read from a location
+ * @dst: pointer to the buffer that shall take the data
+ * @src: address to read from
+ * @size: size of the data chunk
+ *
+ * Safely read from address @src to the buffer at @dst.  If a kernel fault
+ * happens, handle that and return -EFAULT.
+ */
+long probe_kernel_read(void *dst, void *src, size_t size)
+{
+	long ret;
+
+	pagefault_disable();
+	ret = __copy_from_user_inatomic(dst,
+			(__force const void __user *)src, size);
+	pagefault_enable();
+
+	return ret ? -EFAULT : 0;
+}
+EXPORT_SYMBOL_GPL(probe_kernel_read);
+
+/**
+ * probe_kernel_write(): safely attempt to write to a location
+ * @dst: address to write to
+ * @src: pointer to the data that shall be written
+ * @size: size of the data chunk
+ *
+ * Safely write to address @dst from the buffer at @src.  If a kernel fault
+ * happens, handle that and return -EFAULT.
+ */
+long probe_kernel_write(void *dst, void *src, size_t size)
+{
+	long ret;
+
+	pagefault_disable();
+	ret = __copy_to_user_inatomic((__force void __user *)dst, src, size);
+	pagefault_enable();
+
+	return ret ? -EFAULT : 0;
+}
+EXPORT_SYMBOL_GPL(probe_kernel_write);

Re: [git pull] kgdb-light -v10

[Andi Kleen]

On Tue, Feb 12, 2008 at 12:27:47PM +0100, Ingo Molnar wrote:
> > > +	return pid_max + raw_smp_processor_id();
> > 
> > Whatever that shadowpid is. [...]
> 
> GDB wants to track threads, but on the Linux side each idle task has PID 
> 0, so GDB cannot track them. The shadow PID is this remapped space.

Ok, please write that as a comment into the source.

> 
> > That wrapper should not be needed; everybody can use 
> > instruction_pointer() directly, no?
> 
> no, not all architectures have it. This is a weak alias that is 
> otherwise not linked into the kernel.

Can't be very many because oprofile needs it and it works on most archs now.
Anyways, the right thing is to just add it to the architectures
that still miss it, not reimplement it in kgdb.
 
> > > +		if (user_mode(regs))
> > > +			return NOTIFY_DONE;
> > 
> > That seems weird. I think other parts try to support user mode 
> > debugging too. In theory there is no reason it shouldn't be able to do 
> > this (except that you have to make sure to not break regular gdb of 
> > course)
> 
> The currently submitted code does not try to support user mode 
> debugging. It might be a nice add-on later, if done cleanly and 
> correctly enough. If you are interested we welcome patches from you!

Hmm, I'm pretty sure I saw some code that was only useful for the
user case. Perhaps you should take all that out then if it doesn't
work anyways?

a good example is all the code trying to handle user mode mappings.

> 
> > > +	/*
> > > +	 * Lowest-prio notifier priority, we want to be notified last:
> > > +	 */
> > > +	.priority	= -INT_MAX,
> > 
> > This means kcrash will have priority won't it? Doesn't seem correct.
> 
> yes, this means if the user has configured kcrash as well then that will 
> have priority over kgdb. This is the intended behavior.

Seems wrong intended behaviour to me. If kgdb is active it should have priority
over crash dumps.

> 
> > First nobody answered the "kgdb clean enough for a module" high level 
> > question yet. Is it good enough for that?
> 
> i disagree that a kernel debugger should necessarily be a kernel module. 
> It might be nice at a future stage, but right now it would just 
> introduce unnecessary complexity.

The question is less about actually having it as a module, but 
just if the interfaces are clean enough to allow it as a module.
If not you should probably clean them up.


> > > more NR_CPUS spinlocks, there's now proper use of barriers, etc. No 
> > > more silly "timeouts" for locking either ... There's now a very 
> > > well-defined
> > 
> > A timeout for waiting for other CPUs is actually not a bad idea for a 
> > debugger. After all you still want to debug even if some other CPUs 
> > are dead.
> 
> i went for correctness and simplicity first. If a system is hung, the 

If all code is correct, it likely won't need a debugger.
But if you write a debugger you can't assume that.

> debugging CPU might hang too at any time. A timeout on the other hand 


> corrupting debugger data. So for now the rule is 
> very simple.
> 
> timeouts might be an optional "would be nice" feature for later on.

Ok it just makes kgdb useless for a wide range of kernel problems.
Hung CPUs are not that uncommon in my experience.


> 
> > > previously Mark indicated some sort of sprintf return value breakage 
> > > he observed, and kgdb would rely on sprintf return values so i'm 
> > > inclined to leave it as-is. We can fix that later, it's not 
> > > critical.
> > 
> > Pretty much all the proc output and sysfs show functions rely on these 
> > return values, so if there is a problem it is likely very obscure.
> 

> relies on it mostly for user-space "this many bytes were processed" 
> return values and those values are often wrong and user-space just 
> handles it gratiously.

If the return value of read() is wrong not even cat(1) will work
correctly, but lose bytes.

You're saying cat is not supposed to work on /proc? That's certainly
not my experience from many years of successfull cat /proc/... use.

> 
> Anyway, the presence of a few special parsers that impact nothing else 
> but kgdb is not even close to being a merge showstopper, it is something 
> that can be consolidated later on. We've already got 7 instances of KGDB 
> code in the upstream kernel:
> 
>   ./sparc/kernel/sparc-stub.c
>   ./cris/arch-v32/kernel/kgdb.c
>   ./cris/arch-v10/kernel/kgdb.c
>   ./mips/kernel/gdb-stub.c
>   ./frv/kernel/gdb-stub.c
>   ./mn10300/kernel/gdb-stub.c
>   ./ppc/kernel/ppc-stub.c
> 
> so obviously these parsers work in practice.

Sure a lot of ugly code works in practice. If it's clean and maintaintable 
code is another question of course.

-Andi

Re: [git pull] kgdb-light -v10

[Ingo Molnar]

i'm glad that there are no other valid-looking (to me) objections left 
against kgdb-light -v10, other than "it would be nice to have more kgdb 
functionality" and "it would be nice to rewrite the parser", right?
:-)

(It seems we do have a fundamental disagreement about how kgdb should 
act: in my opinion it should never break a correct system, while in your 
opinion apparently it's OK to compromise on that to make debugging 
easier. (find below more detailed arguments about this.) If you do not 
change your position about that issue we'll have to agree to disagree 
about that point.)

So unless i forgot about something (please yell if so), it seems to me 
kgdb is now pretty ready for an upstream merge.

here are my replies to the most recent points you brought up [in order 
of how i perceive the topic's importance]:

* Andi Kleen <andi@firstfloor.org> wrote:

> > i went for correctness and simplicity first. If a system is hung, 
> > the debugging CPU might hang too at any time. A timeout on the other 
> > hand introduces the possibility of a 'dead' CPU just coming back to 
> > life after the 'timeout', corrupting debugger data. So for now the 
> > rule is very simple.
> 
> If all code is correct, it likely won't need a debugger. But if you 
> write a debugger you can't assume that.

i gave you very specific technological reasons for why we dont want to 
do spinning for now: we dont _ever_ want to break a correctly working 
system with kgdb.

A valid counter-argument is _not_ to argue "but it would be nice to have 
if the system is broken in X, Y and Z ways" (like you did), but to point 
it out why the behavior we chose is wrong on a correctly working system.

Yes, a buggy system might misbehave in various ways but my primary 
interest is in keeping correctly working systems correct.

And note that kgdb is not just a "debugger", it's a system inspection 
tool. An intelligent, human-controlled printk. A kernel internals 
learning tool. An extension to the kernel console concept. Yes, people 
frequently use it for debugging too, but the other uses are actually 
more important in the big picture than the debugging aspect.

> > i disagree that a kernel debugger should necessarily be a kernel 
> > module. It might be nice at a future stage, but right now it would 
> > just introduce unnecessary complexity.
> 
> The question is less about actually having it as a module, but just if 
> the interfaces are clean enough to allow it as a module. If not you 
> should probably clean them up.

but your contention is simply wrong. Most of our debugging 
infrastructure is non-modular for a good reason. Modularization 
increases complexity and that's exactly the wrong direction for 
debugging code. (especially for a first-level merge like this one)

> > > Whatever that shadowpid is. [...]
> > 
> > GDB wants to track threads, but on the Linux side each idle task has 
> > PID 0, so GDB cannot track them. The shadow PID is this remapped 
> > space.
> 
> Ok, please write that as a comment into the source.

it's already commented in -v10 at several places.

> > no, not all architectures have it. This is a weak alias that is 
> > otherwise not linked into the kernel.
> 
> Can't be very many because oprofile needs it and it works on most 
> archs now. Anyways, the right thing is to just add it to the 
> architectures that still miss it, not reimplement it in kgdb.

it's not reimplemented - kgdb_arch_pc() does not directly map to 
instruction_pointer().

> > The currently submitted code does not try to support user mode 
> > debugging. It might be a nice add-on later, if done cleanly and 
> > correctly enough. If you are interested we welcome patches from you!
> 
> Hmm, I'm pretty sure I saw some code that was only useful for the user 
> case. Perhaps you should take all that out then if it doesn't work 
> anyways?
> 
> a good example is all the code trying to handle user mode mappings.

that's already all taken out in -v10. (if you find any leftovers then 
please cite the code where it isnt - thanks!)

> [...] If kgdb is active it should have priority over crash dumps.

that's the approach we are taking: be as unintrusive as possible. This 
means that the notifier here is registered at the lowest priority. You 
might disagree with it but it's a completely sensible and consistent 
approach.

	Ingo

Re: [git pull] kgdb-light -v10

[Jason Wessel]

Ingo Molnar wrote:
> * Andi Kleen <andi@firstfloor.org> wrote:
>
>   
>>> i went for correctness and simplicity first. If a system is hung, 
>>> the debugging CPU might hang too at any time. A timeout on the other 
>>> hand introduces the possibility of a 'dead' CPU just coming back to 
>>> life after the 'timeout', corrupting debugger data. So for now the 
>>> rule is very simple.
>>>       
>> If all code is correct, it likely won't need a debugger. But if you 
>> write a debugger you can't assume that.
>>     
>
> i gave you very specific technological reasons for why we dont want to 
> do spinning for now: we dont _ever_ want to break a correctly working 
> system with kgdb.
>
> A valid counter-argument is _not_ to argue "but it would be nice to have 
> if the system is broken in X, Y and Z ways" (like you did), but to point 
> it out why the behavior we chose is wrong on a correctly working system.
>
> Yes, a buggy system might misbehave in various ways but my primary 
> interest is in keeping correctly working systems correct.
>
> And note that kgdb is not just a "debugger", it's a system inspection 
> tool. An intelligent, human-controlled printk. A kernel internals 
> learning tool. An extension to the kernel console concept. Yes, people 
> frequently use it for debugging too, but the other uses are actually 
> more important in the big picture than the debugging aspect.
>
>   

This is not a technical argument, but I am not a big fan of hard hanging
the system if you cannot sync all the CPUs. The original intent was to
at least provide a sync error message to the end user after some
reasonable time. Then allow someone to collect any data you can get and
you basically have to reboot. The reboot was never forced, but assumed
the end users of this knew what they were doing in the first place.

Certainly in a completely working system where you use kgdb only for
inspection this is not an issue, unless you use a breakpoint or single
step one of the smp_call functions. As we all know there are lots of
ways to crash a perfectly working system.

>   
>>> no, not all architectures have it. This is a weak alias that is 
>>> otherwise not linked into the kernel.
>>>       
>> Can't be very many because oprofile needs it and it works on most 
>> archs now. Anyways, the right thing is to just add it to the 
>> architectures that still miss it, not reimplement it in kgdb.
>>     
>
> it's not reimplemented - kgdb_arch_pc() does not directly map to 
> instruction_pointer().
>
>   

We might be best served to add a comment to explain the purpose of
kgdb_arch_pc() and put it in the optional implementation function
headers in include/linux/kgdb.h

On some archs certain exceptions do not report the address that the
exception occurred at when you call instruction_pointer(). This optional
function allows for an arch to perform a "fixup" to get the address the
exception actually occurred at.

Kgdb requires the actual exception address so a sanity check can be
performed to make sure kgdb did not hit an exception while in a chunk of
code kgdb requires for its functionality. If you hit one of these
conditions kgdb makes its best attempt to try to "patch the wound"
inflicted by shooting yourself but at least you get notified vs a silent
hang :-)

Jason.

Re: [git pull] kgdb-light -v10

[Andi Kleen]

On Tue, Feb 12, 2008 at 07:30:15AM -0600, Jason Wessel wrote:
> This is not a technical argument, but I am not a big fan of hard hanging
> the system if you cannot sync all the CPUs. 

Me neither.

> We might be best served to add a comment to explain the purpose of
> kgdb_arch_pc() and put it in the optional implementation function
> headers in include/linux/kgdb.h
> 
> On some archs certain exceptions do not report the address that the
> exception occurred at when you call instruction_pointer(). This optional
> function allows for an arch to perform a "fixup" to get the address the
> exception actually occurred at.

Shouldn't that be handled in the remote gdb?

> 
> Kgdb requires the actual exception address so a sanity check can be
> performed to make sure kgdb did not hit an exception while in a chunk of
> code kgdb requires for its functionality. If you hit one of these

That was for the old longjmp checks, but that code is long gone isn't it
and replacement with standard __ex_table handling.

> conditions kgdb makes its best attempt to try to "patch the wound"
> inflicted by shooting yourself but at least you get notified vs a silent
> hang :-)

In what cases is that still needed?

-Andi

Re: [git pull] kgdb-light -v10

[Jason Wessel]

Andi Kleen wrote:
>> We might be best served to add a comment to explain the purpose of
>> kgdb_arch_pc() and put it in the optional implementation function
>> headers in include/linux/kgdb.h
>>
>> On some archs certain exceptions do not report the address that the
>> exception occurred at when you call instruction_pointer(). This optional
>> function allows for an arch to perform a "fixup" to get the address the
>> exception actually occurred at.
> 
> Shouldn't that be handled in the remote gdb?

No this is a kgdb integrity check.

Basically when you reach this chunk of code it is before the hand off
to the source debugger.  We cannot continue because there was a
breakpoint in a part of the system kgdb was using while doing its
normal work.  The reality is that KGDB is not self contained.  It
relies on some external I/O methods, atomic page fault handling and
some other pieces.  If you take an exception there, the kgdb integrity
check absolutely needs to fail.

It was the source of some great pain for folks who tried to use kgdb
for more than an inspection tool.  There are some parts of the system
you cannot debug.


> 
>> Kgdb requires the actual exception address so a sanity check can be
>> performed to make sure kgdb did not hit an exception while in a chunk of
>> code kgdb requires for its functionality. If you hit one of these
> 
> That was for the old longjmp checks, but that code is long gone isn't it
> and replacement with standard __ex_table handling.

This has nothing to do with the long jump

> 
>> conditions kgdb makes its best attempt to try to "patch the wound"
>> inflicted by shooting yourself but at least you get notified vs a silent
>> hang :-)
> 
> In what cases is that still needed?
> 

This is a totally stupid test case but it should illustrate the problem.

- connect to kgdb
- place a break point at kgdb_disable_hw_debug()
- continue
- Now try to break in again

You will see the kgdb integrity check fail because you put a
breakpoint in a place that kgdb actually needs to perform its work.
In this case kgdb will clean up the exception and restore operation
and you will be ok.  The kgdboc has a much smaller swath of code that
you cannot debug vs something like kgdboe where there are lot more
places you cannot debug due to the amount of code to services the
ethernet device, irq sync etc...

This check is absolutely required to help prevent silent death via
dumb breakpoints or stepping around in random places (which is ill
advised anyway).

Jason.

Re: [git pull] kgdb-light -v10

[Andi Kleen]

> Basically when you reach this chunk of code it is before the hand off
> to the source debugger.  We cannot continue because there was a
> breakpoint in a part of the system kgdb was using while doing its
> normal work.  The reality is that KGDB is not self contained.  It
> relies on some external I/O methods, atomic page fault handling and
> some other pieces.  If you take an exception there, the kgdb integrity
> check absolutely needs to fail.

Don't you just need a simple recursion counter for this? 

I cannot think of a reliable simple way to check for this using the instruction
pointer. The only way would be to use explicit annotations for all
possible code similar to what kprobes does (__kprobes), but that would be 
hugely intrusive all over the tree.

With the recursion counter the only problem would be someone 
setting a break point on the early notifier code itself that contains
a recursion check, but that would be only a few lines of code
so the risk of someone setting a break point exactly there would
be low.

> This check is absolutely required to help prevent silent death via
> dumb breakpoints or stepping around in random places (which is ill
> advised anyway).

I believe you, but I don't believe that your implementation
of this handles all cases.

-Andi

Re: [git pull] kgdb-light -v10

[Jason Wessel]

Andi Kleen wrote:
>> Basically when you reach this chunk of code it is before the hand off
>> to the source debugger.  We cannot continue because there was a
>> breakpoint in a part of the system kgdb was using while doing its
>> normal work.  The reality is that KGDB is not self contained.  It
>> relies on some external I/O methods, atomic page fault handling and
>> some other pieces.  If you take an exception there, the kgdb integrity
>> check absolutely needs to fail.
>>     
>
> Don't you just need a simple recursion counter for this? 
>
> I cannot think of a reliable simple way to check for this using the instruction
> pointer. The only way would be to use explicit annotations for all
> possible code similar to what kprobes does (__kprobes), but that would be 
> hugely intrusive all over the tree.
>
> With the recursion counter the only problem would be someone 
> setting a break point on the early notifier code itself that contains
> a recursion check, but that would be only a few lines of code
> so the risk of someone setting a break point exactly there would
> be low.
>   

It is more than a simple recursion check (which is already in the code)
because there are some conditions we can recover from.  I'd rather not
crash the system out if it can be recovered.

kgdb_reenter_check() has the "simple" recursion check with the
exception_level variable.

It also has several special checks against the breakpoint situation I
described before as well as trying to remove all the breakpoints.  
Ultimately if all those checks fails, it results in panic, because at
the end of the day that is all you can do if you re-enter the debugger
from the debugger (IE: you are toast).

I don't see any reason to change the code there unless it can be further
improved some way.  We want to fail loudly and verbosely when this kind
of thing happens so we can determine if it was the end user that caused
the problem or if there is a real defect.

Jason.

Re: [git pull] kgdb-light -v10

[Andi Kleen]

> It is more than a simple recursion check (which is already in the code)
> because there are some conditions we can recover from.  I'd rather not
> crash the system out if it can be recovered.

Ok I'm trying to understand the code as you describe it. As far 
as I can see (in kgdb-light-v10) it is:

+       addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
+       kgdb_deactivate_sw_breakpoints();
+
+       /*
+        * If the break point removed ok at the place exception
+        * occurred, try to recover and print a warning to the end
+        * user because the user planted a breakpoint in a place that
+        * KGDB needs in order to function.
+        */
+       if (kgdb_remove_sw_break(addr) == 0) {

and

+static int kgdb_remove_sw_break(unsigned long addr)
+{
+       int i;
+
+       for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+               if ((kgdb_break[i].state == BP_SET) &&
+                               (kgdb_break[i].bpt_addr == addr)) {
+                       kgdb_break[i].state = BP_REMOVED;
+                       return 0;
+               }
+       }
+       return -ENOENT;

correct? 

I don't think that code does what you describe at all. Are you
sure we're talking about the same thing? 

There is certainly no real protection against break points in
debugger code in there as far as I can see (except for the reentry
counter)

-Andi

Re: [git pull] kgdb-light -v10

[Jason Wessel]

Andi Kleen wrote:
>> It is more than a simple recursion check (which is already in the code)
>> because there are some conditions we can recover from.  I'd rather not
>> crash the system out if it can be recovered.
>>     
>
> Ok I'm trying to understand the code as you describe it. As far 
> as I can see (in kgdb-light-v10) it is:
>
> +       addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
> +       kgdb_deactivate_sw_breakpoints();
> +
> +       /*
> +        * If the break point removed ok at the place exception
> +        * occurred, try to recover and print a warning to the end
> +        * user because the user planted a breakpoint in a place that
> +        * KGDB needs in order to function.
> +        */
> +       if (kgdb_remove_sw_break(addr) == 0) {
>
> and
>
> +static int kgdb_remove_sw_break(unsigned long addr)
> +{
> +       int i;
> +
> +       for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
> +               if ((kgdb_break[i].state == BP_SET) &&
> +                               (kgdb_break[i].bpt_addr == addr)) {
> +                       kgdb_break[i].state = BP_REMOVED;
> +                       return 0;
> +               }
> +       }
> +       return -ENOENT;
>
> correct? 
>
> I don't think that code does what you describe at all. Are you
> sure we're talking about the same thing? 
>
> There is certainly no real protection against break points in
> debugger code in there as far as I can see (except for the reentry
> counter)
>
>   

Perhaps we are talking about different things.  I will agree that there
is no protection against putting a breakpoint in some code that is part
of the debugger.  That was certainly not what I was talking about.

You might be able to perform some protections at the breakpoint set time
or request to single step, but that is much more complex than is worth
it for the time being.  The recursion check guards against basic
stupidity or accidental stepping out of a frame you didn't mean to. 
Also there are a lot of non-obvious code paths that can get executed via
kgdb such as the fault handlers.  The simple recursion check covers
enough cases that you don't want to live without it.

If you want to improve it please provide some patches or further
elaborate on what needs to be fixed.

Jason

Re: [git pull] kgdb-light -v10

[Andi Kleen]

On Tue, Feb 12, 2008 at 01:38:39PM +0100, Ingo Molnar wrote:
> So unless i forgot about something (please yell if so), it seems to me 
> kgdb is now pretty ready for an upstream merge.

I don't know -- I have not reread everything. Please don't consider
my comments as approval of the code base. I still think it does quite
a lot of dubious and ugly things overall and should get far more clean up
and get more testing too.

> do spinning for now: we dont _ever_ want to break a correctly working 
> system with kgdb.

Stopping all CPUs for indefinite time very much seems like 
"breaking a correctly working system" to me.  In a correctly working system 
kgdb is never entered.

> A valid counter-argument is _not_ to argue "but it would be nice to have 
> if the system is broken in X, Y and Z ways" (like you did), but to point 
> it out why the behavior we chose is wrong on a correctly working system.
> 
> Yes, a buggy system might misbehave in various ways but my primary 
> interest is in keeping correctly working systems correct.

The only way I know of to do that is gdb vmlinux /proc/kcore 
kgdb certainly isn't it.

> And note that kgdb is not just a "debugger", it's a system inspection 
> tool. An intelligent, human-controlled printk.

For that gdb vmlinux /proc/kcore already works fine. Or fireproxy.
If that was the only goal we wouldn't need all that stub code.


> > > just introduce unnecessary complexity.
> > 
> > The question is less about actually having it as a module, but just if 
> > the interfaces are clean enough to allow it as a module. If not you 
> > should probably clean them up.
> 
> but your contention is simply wrong. Most of our debugging 
> infrastructure is non-modular for a good reason. Modularization 
> increases complexity and that's exactly the wrong direction for 

The main complexity in module handling is handling (or rather preventing)
module unload.  I explicitely excluded that in my earlier mail. 
Module loading on the other hand tends to be relatively easy.

I did a modular kernel debugger on my own some time ago and once
the interfaces were clean it was very simple. I think the reverse
is true too -- if having it as a module is easy then the interfaces
are clean too. That is why I asked for it. It's a good basic
sanity check on the design.

> 
> > > no, not all architectures have it. This is a weak alias that is 
> > > otherwise not linked into the kernel.
> > 
> > Can't be very many because oprofile needs it and it works on most 
> > archs now. Anyways, the right thing is to just add it to the 
> > architectures that still miss it, not reimplement it in kgdb.
> 
> it's not reimplemented - kgdb_arch_pc() does not directly map to 
> instruction_pointer().

If that is true then it is definitely misnamed and likely 
incorrectly implemented on the architecture in question.

> > [...] If kgdb is active it should have priority over crash dumps.
> 
> that's the approach we are taking: be as unintrusive as possible. This 
> means that the notifier here is registered at the lowest priority. You 
> might disagree with it but it's a completely sensible and consistent 
> approach.

Yeah, it is consistently wrong agreed.

-Andi

Re: [git pull] kgdb-light -v10

[Ingo Molnar]

* Andi Kleen <andi@firstfloor.org> wrote:

> On Tue, Feb 12, 2008 at 01:38:39PM +0100, Ingo Molnar wrote:
> > So unless i forgot about something (please yell if so), it seems to 
> > me kgdb is now pretty ready for an upstream merge.
> 
> I don't know -- I have not reread everything. Please don't consider my 
> comments as approval of the code base. [...]

well, it does not take a mindreader to conclude that nothing we do could 
possibly result in you "concluding" that kgdb would be ready for a merge 
;-)

for me it suffices that you've run out of technical arguments and are 
resorting to non-technical name-calling:

> [...] I still think it does quite a lot of dubious and ugly things 
> overall [...]

	Ingo

Re: [git pull] kgdb-light -v10

[Andi Kleen]

Ingo Molnar <mingo@elte.hu> writes:

> * Andi Kleen <andi@firstfloor.org> wrote:
>
>> On Tue, Feb 12, 2008 at 01:38:39PM +0100, Ingo Molnar wrote:
>> > So unless i forgot about something (please yell if so), it seems to 
>> > me kgdb is now pretty ready for an upstream merge.
>> 
>> I don't know -- I have not reread everything. Please don't consider my 
>> comments as approval of the code base. [...]
>
> well, it does not take a mindreader to conclude that nothing we do could 
> possibly result in you "concluding" that kgdb would be ready for a merge 
> ;-)
>
> for me it suffices that you've run out of technical arguments and are 
> resorting to non-technical name-calling:
>
>> [...] I still think it does quite a lot of dubious and ugly things 
>> overall [...]

Let's put it like this: the amount of problems I found by reading
only about 20% of the kgdb patch justifies the statement above. Also
contrary to your repeated claims many of those are not fixed yet
as far as I can see.

Also every time I dig into something new problems raise their
head -- e.g. see earlier exchange with Jason about the likely
bogus recursion check.

Overall that's not a sign of a clean merge ready code base.

-Andi

Re: [git pull] kgdb-light -v10

[Ingo Molnar]

* Andi Kleen <andi@firstfloor.org> wrote:

> > do spinning for now: we dont _ever_ want to break a correctly 
> > working system with kgdb.
> 
> Stopping all CPUs for indefinite time very much seems like "breaking a 
> correctly working system" to me. [...]

well, this is a small detail, but still you are wrong, and on a 
correctly working system this will not occur. (if yes, tell me how)

KGDB does a very straightforward "all CPUs enter controlled state" 
transition when the session begins, and at the end an "all CPUs 
continue" transition.

I'm not sure what you mean exactly under "stopping all CPUs for 
indefinite amount of time" (your statement is sufficiently vague to be 
hard to counter via specifics) - that does not happen, unless the system 
is so buggy that a CPU is not able to process an NMI anymore [which is 
rather rare] - in that case the whole system is likely locked up anyway. 
In that case the simplest and safest behavior is what kgdb-light does 
currently: it will only proceed if all CPUs have responded. Note that 
you are wrong to suggest that "KGDB locks up", the system _has already 
locked up_.

yes, we could "time out" and force a KGDB session even if some CPUs do 
not respond. But it's obviously not a completely safe system state, 
because other CPUs might be changing things under the feet of the 
debugger. So the safest first-level approach is to not enter the 
debugger in this case.

	Ingo

Re: [git pull] kgdb-light -v10

[Andi Kleen]

On Tue, Feb 12, 2008 at 04:28:46PM +0100, Ingo Molnar wrote:
> 
> * Andi Kleen <andi@firstfloor.org> wrote:
> 
> > > do spinning for now: we dont _ever_ want to break a correctly 
> > > working system with kgdb.
> > 
> > Stopping all CPUs for indefinite time very much seems like "breaking a 
> > correctly working system" to me. [...]
> 
> well, this is a small detail, but still you are wrong, and on a 
> correctly working system this will not occur. (if yes, tell me how)
> 
> KGDB does a very straightforward "all CPUs enter controlled state" 
> transition when the session begins, and at the end an "all CPUs 
> continue" transition.

Yes and the session has no fixed time limit.

> 
> I'm not sure what you mean exactly under "stopping all CPUs for 
> indefinite amount of time" (your statement is sufficiently vague to be 

Stopping with interrupts off. Nothing scheduled anymore. 

An easy definition for the condition is anything that requires 
touch_{nmi,softlockup}_watchdog [which kgdb definitely does, 
although in a quite convoluted way]

> yes, we could "time out" and force a KGDB session even if some CPUs do 
> not respond. But it's obviously not a completely safe system state, 
> because other CPUs might be changing things under the feet of the 
> debugger. So the safest first-level approach is to not enter the 

While that is a slight risk that problem is already there anyways.
Lots of agents in the system could do that. Do you plan to stop
all DMA too for example if you're so worried about this? 
Or how about SMM code changing something? 

Anyways the slight risk of the other CPUs eventually recovering
would seem a acceptable trade off versus not being able to use
the debugger to debug the system with hanging CPUs. 

A possible compromise between my and your position on this would 
be also having an option for this, with default to off
(although I would expect that would be a inconvenient default for
many people)

-Andi (who retires from this thread now, I already spent too much on this)

Re: [git pull] kgdb-light -v10

[Ingo Molnar]

* Andi Kleen <andi@firstfloor.org> wrote:

> Anyways the slight risk of the other CPUs eventually recovering would 
> seem a acceptable trade off versus not being able to use the debugger 
> to debug the system with hanging CPUs.

see? There's the difference between us. The initial merge of KGDB does 
not want to include policies for nuances that pose an "acceptable slight 
risk".

Had we done it, you could have (rightfully in that case, i have to say) 
complained about that "slight but real danger" of a debugger activating 
without waiting for all CPUs to respond.

> A possible compromise between my and your position on this would be 
> also having an option for this, with default to off (although I would 
> expect that would be a inconvenient default for many people)

yes, i said this the first time you mentioned this issue that while it's 
all no big deal, it could perhaps be a sensible (but default-off) 
layered-on option for later. But the initial merge is for obvious stuff 
and it does not want to do such things.

	Ingo

Re: [git pull] kgdb-light -v10

[Andi Kleen]

On Tue, Feb 12, 2008 at 05:24:08PM +0100, Ingo Molnar wrote:
> 
> * Andi Kleen <andi@firstfloor.org> wrote:
> 
> > Anyways the slight risk of the other CPUs eventually recovering would 
> > seem a acceptable trade off versus not being able to use the debugger 
> > to debug the system with hanging CPUs.
> 
> see? There's the difference between us. The initial merge of KGDB does 
> not want to include policies for nuances that pose an "acceptable slight 
> risk".

Ok fine. Please implement DMA quiescence on kgdb entry then; otherwise
the code won't conform to your standards at all.

-Andi

Re: [git pull] kgdb-light -v10

[Linus Torvalds]

On Tue, 12 Feb 2008, Andi Kleen wrote:
> > 
> > KGDB does a very straightforward "all CPUs enter controlled state" 
> > transition when the session begins, and at the end an "all CPUs 
> > continue" transition.
> 
> Yes and the session has no fixed time limit.

Quite frankly, if kgdb starts doing somethign "fancy", there is no way 
I'll merge it.

This includes things like having "breakpoint reservations" (discussed 
earlier) and just generally trying to add lots of infrastructure to make 
kgdb "fit in" to the kernel.

The fact is, not having kgdb enabled should have _zero_ impact on the 
kernel, but the implication is also that when you *do* enable kgdb, that 
shouldn't change anything visible either: the rest of the kernel should 
simply not _possibly_ be able to even tell or care (which is why 
breakpoint reservations are out - they are against the whole point of 
debugging a unmodified kernel).

So kgdb in my opinion will *have* to step on some other kernel 
infrastructure. I also think that things like timeouts are not something 
the client should do - if a kgdb lock never gets through, then it should 
be the debugging end that should just react to ^C and tough titties: it's 
not like there's a whole lot to be done.

In other words: I think the kgdb patches have become a lot more palatable 
over the last week, but I think so exactly because they have gotten 
smaller and less invasive. Anything that evokes any discussion AT ALL 
should just be removed. It really should be that simple.

[ The exception being that I think hw breakpoint support should be added 
  back in - never mind that it won't work if the "native kernel" also uses 
  them. Tough.

  If the debugger screws up the hw breakpoint state, that's a debugger 
  error. I'd hope that the remote debugger *defaults* to just re-writing 
  the instruction stream for that reason, but if you want to do a data 
  breakpoint, you simply *have* to use the hw breakpoints for kgdb.

  And you just need to live with the fact that it simply won't be possible 
  to do if the client wants to use hw breakpoints too. If the client 
  starts using hw breakpoints - tough titties, it takes them. ]

So keep the damn thing really simple, and don't try to handle every 
possible thing. We expect the debugger side to have a person with some 
flexibility on it.

			Linus

Re: [git pull] kgdb-light -v10

[Ingo Molnar]

* Linus Torvalds <torvalds@linux-foundation.org> wrote:

> > Yes and the session has no fixed time limit.
> 
> Quite frankly, if kgdb starts doing somethign "fancy", there is no way 
> I'll merge it.
> 
> This includes things like having "breakpoint reservations" (discussed 
> earlier) and just generally trying to add lots of infrastructure to 
> make kgdb "fit in" to the kernel.

yes - i zapped hw breakpoint support in -v10 already.

> In other words: I think the kgdb patches have become a lot more 
> palatable over the last week, but I think so exactly because they have 
> gotten smaller and less invasive. Anything that evokes any discussion 
> AT ALL should just be removed. It really should be that simple.

yes, that's what i've been doing. When anything became questionable even 
just a little bit, it was the axe or i changed it to something really 
obvious and correct.

by 2.6.26 kgdb-light will become so neutral to the rest of the kernel 
that we wont even notice that we've merged it ;-)

> [ The exception being that I think hw breakpoint support should be
>   added back in - never mind that it won't work if the "native kernel" 
>   also uses them. Tough.

yeah. I believe we need to achieve a "known zero impact, 100% trustable" 
state for KGDB to start with, and add stuff carefully to it.

> So keep the damn thing really simple, and don't try to handle every 
> possible thing. We expect the debugger side to have a person with some 
> flexibility on it.

yes - if something locks up, it will be the NMI watchdog starting the 
debugger eventually - not the other way around. The NMI watchdog is 
already system policy which can be turned on/off and is well known and 
expresses the user's wishes with what should happen to the system.

The debugger should really be a fundamentally very passive "console" 
type of thing, with as little direct policy as possible. That minimizes 
the chance that it accidentally messes up something and also makes it 
more likely that it will actually work reliably and dependably.

	Ingo

Re: [git pull] kgdb-light -v10

[Andi Kleen]

> This includes things like having "breakpoint reservations" (discussed 
> earlier) and just generally trying to add lots of infrastructure to make 
> kgdb "fit in" to the kernel.

I think that part is actually mostly ok now (old kgdb stubs were
much worse in this regard) 

I still think the ultimative proof for this would be working
"modprobe kgdb" though.

> 
> The fact is, not having kgdb enabled should have _zero_ impact on the 
> kernel, but the implication is also that when you *do* enable kgdb, that 
> shouldn't change anything visible either: the rest of the kernel should 

While agreed in theory there are some exceptions: any time an oops
happens or a crash dump would happen automatically kgdb should definitely
do something very visible. Unfortunately that's not always the case
currently (see earlier comments on the notifier priority) 

> So kgdb in my opinion will *have* to step on some other kernel 
> infrastructure. I also think that things like timeouts are not something 
> the client should do - if a kgdb lock never gets through, then it should 
> be the debugging end that should just react to ^C and tough titties: it's 
> not like there's a whole lot to be done.

The problem here is that the timeout we were talking about 
is not integrated into the kgdb event loop, it is rather the loop
that protects the event loop. If you hang there all input
from the outside will be ignored.

> So keep the damn thing really simple, and don't try to handle every 
> possible thing. We expect the debugger side to have a person with some 
> flexibility on it.

If you want areally simple kgdb the best option would be re-porting
the really simple (tm) 2.4 era x86-64 kgdb stub I did long ago.
It had a small fraction of the code size of the current code, but
was also missing a lot of features of course.

-Andi

[RFC][PATCH] modular kgdb-light (was: Re: [git pull] kgdb-light -v10)

[Jan Kiszka]

Andi Kleen wrote:
>> This includes things like having "breakpoint reservations" (discussed 
>> earlier) and just generally trying to add lots of infrastructure to make 
>> kgdb "fit in" to the kernel.
> 
> I think that part is actually mostly ok now (old kgdb stubs were
> much worse in this regard) 
> 
> I still think the ultimative proof for this would be working
> "modprobe kgdb" though.

To pick up this idea again I did the experimental patch below. It
applies against Jason's latest kgdb-light patch queue:

http://git.kernel.org/?p=linux/kernel/git/jwessel/linux-2.6-kgdb.git;a=shortlog;h=for_ingo

The patch nicely demonstrates what deeper dependencies on kernel
services currently exist in kgdb-light. The following symbols were
unresolvable:

 o genapic - for send_IPI_allbutself, ie. CPU roundup
 o machine_emergency_restart - for implementing "R0" gdb packet
 o idle_task - kgdb tells the per-cpu idle tasks apart
 o clocksource_touch_watchdog - obvious

For simplicity reasons I just gpl-exported all of them. The result is
a fully modular kgdb that may help to reduce concerns regarding its
intrusiveness.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

---
 arch/x86/kernel/Makefile               |    4 +++-
 arch/x86/kernel/genapic_64.c           |    1 +
 arch/x86/kernel/{kgdb.c => kgdb-x86.c} |    0 
 arch/x86/kernel/reboot.c               |    1 +
 arch/x86/mach-generic/probe.c          |    1 +
 kernel/Makefile                        |    1 -
 kernel/sched.c                         |    1 +
 kernel/time/clocksource.c              |    1 +
 lib/Kconfig.kgdb                       |    2 +-
 {kernel => lib}/kgdb.c                 |    8 ++++++--
 10 files changed, 15 insertions(+), 5 deletions(-)
 rename arch/x86/kernel/{kgdb.c => kgdb-x86.c} (100%)
 rename {kernel => lib}/kgdb.c (100%)

diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 4cd39cd..2e733b1 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -58,7 +58,6 @@ obj-$(CONFIG_MODULES)		+= module_$(BITS).o
 obj-$(CONFIG_ACPI_SRAT) 	+= srat_32.o
 obj-$(CONFIG_EFI) 		+= efi.o efi_$(BITS).o efi_stub_$(BITS).o
 obj-$(CONFIG_DOUBLEFAULT) 	+= doublefault_32.o
-obj-$(CONFIG_KGDB)		+= kgdb.o
 obj-$(CONFIG_VM86)		+= vm86_32.o
 obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
 
@@ -79,6 +78,9 @@ endif
 obj-$(CONFIG_SCx200)		+= scx200.o
 scx200-y			+= scx200_32.o
 
+kgdb-objs			:= ../../../lib/kgdb.o kgdb-x86.o
+obj-$(CONFIG_KGDB)		+= kgdb.o
+
 ###
 # 64 bit specific files
 ifeq ($(CONFIG_X86_64),y)
diff --git a/arch/x86/kernel/genapic_64.c b/arch/x86/kernel/genapic_64.c
index 4ae7b64..d0518a7 100644
--- a/arch/x86/kernel/genapic_64.c
+++ b/arch/x86/kernel/genapic_64.c
@@ -32,6 +32,7 @@ DEFINE_PER_CPU(u16, x86_cpu_to_apicid) = BAD_APICID;
 EXPORT_PER_CPU_SYMBOL(x86_cpu_to_apicid);
 
 struct genapic __read_mostly *genapic = &apic_flat;
+EXPORT_SYMBOL_GPL(genapic);
 
 /*
  * Check the APIC IDs in bios_cpu_apicid and choose the APIC mode.
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb-x86.c
similarity index 100%
rename from arch/x86/kernel/kgdb.c
rename to arch/x86/kernel/kgdb-x86.c
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 5818dc2..66d7c27 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -375,6 +375,7 @@ void machine_emergency_restart(void)
 		}
 	}
 }
+EXPORT_SYMBOL_GPL(machine_emergency_restart);
 
 void machine_shutdown(void)
 {
diff --git a/arch/x86/mach-generic/probe.c b/arch/x86/mach-generic/probe.c
index f410d3c..4156d64 100644
--- a/arch/x86/mach-generic/probe.c
+++ b/arch/x86/mach-generic/probe.c
@@ -21,6 +21,7 @@ extern struct genapic apic_es7000;
 extern struct genapic apic_default;
 
 struct genapic *genapic = &apic_default;
+EXPORT_SYMBOL_GPL(genapic);
 
 static struct genapic *apic_probe[] __initdata = {
 	&apic_summit,
diff --git a/kernel/Makefile b/kernel/Makefile
index 05c8003..6c584c5 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -53,7 +53,6 @@ obj-$(CONFIG_AUDIT) += audit.o auditfilter.o
 obj-$(CONFIG_AUDITSYSCALL) += auditsc.o
 obj-$(CONFIG_AUDIT_TREE) += audit_tree.o
 obj-$(CONFIG_KPROBES) += kprobes.o
-obj-$(CONFIG_KGDB) += kgdb.o
 obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
 obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
 obj-$(CONFIG_SECCOMP) += seccomp.o
diff --git a/kernel/sched.c b/kernel/sched.c
index 3eedd52..e2ffff4 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4463,6 +4463,7 @@ struct task_struct *idle_task(int cpu)
 {
 	return cpu_rq(cpu)->idle;
 }
+EXPORT_SYMBOL_GPL(idle_task);
 
 /**
  * find_process_by_pid - find a process with a matching PID value.
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index ace23d3..e83dc5d 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -238,6 +238,7 @@ void clocksource_touch_watchdog(void)
 {
 	clocksource_resume_watchdog();
 }
+EXPORT_SYMBOL_GPL(clocksource_touch_watchdog);
 
 /**
  * clocksource_get_next - Returns the selected clocksource
diff --git a/lib/Kconfig.kgdb b/lib/Kconfig.kgdb
index 9631ba3..413e3b8 100644
--- a/lib/Kconfig.kgdb
+++ b/lib/Kconfig.kgdb
@@ -1,6 +1,6 @@
 
 menuconfig KGDB
-	bool "KGDB: kernel debugging with remote gdb"
+	tristate "KGDB: kernel debugging with remote gdb"
 	select FRAME_POINTER
 	depends on HAVE_ARCH_KGDB
 	depends on DEBUG_KERNEL && EXPERIMENTAL
diff --git a/kernel/kgdb.c b/lib/kgdb.c
similarity index 100%
rename from kernel/kgdb.c
rename to lib/kgdb.c
index b516de0..2ef8e9d 100644
--- a/kernel/kgdb.c
+++ b/lib/kgdb.c
@@ -91,13 +91,14 @@ static int kgdb_con_registered;
 /* determine if kgdb console output should be used */
 static int kgdb_use_con;
 
+#ifdef CONFIG_KGDB
 static int __init opt_kgdb_con(char *str)
 {
 	kgdb_use_con = 1;
 	return 0;
 }
-
 early_param("kgdbcon", opt_kgdb_con);
+#endif
 
 module_param(kgdb_use_con, int, 0644);
 
@@ -1667,6 +1668,7 @@ void kgdb_breakpoint(void)
 }
 EXPORT_SYMBOL_GPL(kgdb_breakpoint);
 
+#ifdef CONFIG_KGDB
 static int __init opt_kgdb_wait(char *str)
 {
 	kgdb_break_asap = 1;
@@ -1676,5 +1678,7 @@ static int __init opt_kgdb_wait(char *str)
 
 	return 0;
 }
-
 early_param("kgdbwait", opt_kgdb_wait);
+#endif
+
+MODULE_LICENSE("GPL");

Re: [RFC][PATCH] modular kgdb-light (was: Re: [git pull] kgdb-light -v10)

[Andi Kleen]

On Fri, Feb 15, 2008 at 01:35:36PM +0100, Jan Kiszka wrote:
> Andi Kleen wrote:
> >> This includes things like having "breakpoint reservations" (discussed 
> >> earlier) and just generally trying to add lots of infrastructure to make 
> >> kgdb "fit in" to the kernel.
> > 
> > I think that part is actually mostly ok now (old kgdb stubs were
> > much worse in this regard) 
> > 
> > I still think the ultimative proof for this would be working
> > "modprobe kgdb" though.
> 
> To pick up this idea again I did the experimental patch below. It
> applies against Jason's latest kgdb-light patch queue:

Very nice! If it's that simple then the kgdb integration is really
clean.

> 
> http://git.kernel.org/?p=linux/kernel/git/jwessel/linux-2.6-kgdb.git;a=shortlog;h=for_ingo
> 
> The patch nicely demonstrates what deeper dependencies on kernel
> services currently exist in kgdb-light. The following symbols were
> unresolvable:
> 

Some comments on the specific patch:

>  o genapic - for send_IPI_allbutself, ie. CPU roundup

I would rather export some generic wrapper for that than the full genapic
structure.

>  o machine_emergency_restart - for implementing "R0" gdb packet

Hmm, might be a bit dangerous to call this directly -- there are various
quirks with e.g. not rebooting on CPU #0 and not resetting APIC 
state. But ok [this is not directly related to the fact that it's
exported now, just mentioning this in general]

-Andi

Re: [RFC][PATCH] modular kgdb-light

[Jason Wessel]

Andi Kleen wrote:
> On Fri, Feb 15, 2008 at 01:35:36PM +0100, Jan Kiszka wrote:
>   
>>  o machine_emergency_restart - for implementing "R0" gdb packet
>>     
>
> Hmm, might be a bit dangerous to call this directly -- there are various
> quirks with e.g. not rebooting on CPU #0 and not resetting APIC 
> state. But ok [this is not directly related to the fact that it's
> exported now, just mentioning this in general]
>
>   
kgdb was never expected to be any better than using a sysrq-b.   Unless
you put some really ugly code in to deal with lots of edge cases there
are certainly times it is just going to force you to press the power
button.  If there is a better function for "reset now and cross fingers"
kgdb can be changed easily enough to do that.

Also given that you can have more than one type of "R" packet it would
be easy enough to add other reboot types, such as an R1 which might call
to the bios or another means to reset.  For now the intent is pretty
clear and there is not likely a need to expand the scope.

Jason.

Re: [git pull] kgdb-light -v10

[Jason Wessel]

Linus Torvalds wrote:
> [ The exception being that I think hw breakpoint support should be added
> back in - never mind that it won't work if the "native kernel" also uses
> them. Tough.
>
> If the debugger screws up the hw breakpoint state, that's a debugger
> error. I'd hope that the remote debugger *defaults* to just re-writing
> the instruction stream for that reason, but if you want to do a data
> breakpoint, you simply *have* to use the hw breakpoints for kgdb.
>
> And you just need to live with the fact that it simply won't be possible
> to do if the client wants to use hw breakpoints too. If the client
> starts using hw breakpoints - tough titties, it takes them. ]
>
> So keep the damn thing really simple, and don't try to handle every
> possible thing. We expect the debugger side to have a person with some
> flexibility on it.
>
> Linus

HW breakpoints (particularly data breakpoints) are extremely useful
and I am proposing to put them back into kgdb-light. The HW
breakpoint patch worked exactly as described. If the user space
writes into the HW breakpoint registers via ptrace, those take
priority over the kernel HW breakpoints.

We have to assume that the person debugging the kernel ultimately has
full control of the system, and will do what ever is needed to
debug/inspect the kernel how he or she chooses.

Of course at some future time if there is a generic API to use for the
kernel level HW breakpoints, kgdb can adapt like anything else.

Jason.

Re: [git pull] kgdb-light -v10

[Linus Torvalds]

On Tue, 12 Feb 2008, Ingo Molnar wrote:
> 
> * Andi Kleen <andi@firstfloor.org> wrote:
> > 
> > Stopping all CPUs for indefinite time very much seems like "breaking a 
> > correctly working system" to me. [...]
> 
> well, this is a small detail, but still you are wrong, and on a 
> correctly working system this will not occur. (if yes, tell me how)

Quite frankly, I don't see why the kernel kgdb layer should have *any* 
code like this at all.

The one who is actually debugging is the one who should decide which CPU's 
get stopped, and which don't.

I realize that the gdb remote protocol is probably a piece of crap and 
cannot handle that, but hey, that's not my problem, and more importantly, 
I don't think it's even a *remotely* valid reason for making bad decisions 
in the kernel. gdb was still open source last time I saw, and I think it's 
reasonable to just say:

 - the kgdb commands should always act on the *current* CPU only
 - add one command that says "switch over to CPU #n" which just releases 
   the current CPU and sends an IPI to that CPU #n (no timeouts, no 
   synchronous waiting, no nothing - it's like a "continue", but with a 
   "try to get the other CPU to stop"

Yes, other CPU's will obviously often end up stopping due to waiting for 
some spinlock or other if we stop one, but that's a separate issue, and 
quite often it might be sufficient - and what we want.

And yes, you'd likely have to add some support to gdb to make this 
_usable_, but now all that usability crap, all those timeouts for "stop 
all CPU's" are now in user space on the _debugger_ side. That can be as 
fancy as it wants to be.

And maybe this isn't realistic. I'm not saying "we _must_ do it this way", 
I just want to say that the kernel kgdb layer should be as thin ass 
humanly possible, and maybe the right thing to do is to simply totally 
punt on the whole "stop other cpu's" issue and make it a debugger-side 
question.

In other words, is it perhaps possible to just *get*rid*of* that 
"kgdb_active" and "nmicallback" and the whole multi-CPU roundup? Just use 
a kgdb spinlock around the stuff that actually sends and receives 
individual packets, and expect the debugger side to sort them out (yeah, I 
suspect this involves having to add the CPU ID to each packet).

			Linus

Re: [git pull] kgdb-light -v10

[Ingo Molnar]

* Linus Torvalds <torvalds@linux-foundation.org> wrote:

> In other words, is it perhaps possible to just *get*rid*of* that 
> "kgdb_active" and "nmicallback" and the whole multi-CPU roundup? Just 
> use a kgdb spinlock around the stuff that actually sends and receives 
> individual packets, and expect the debugger side to sort them out 
> (yeah, I suspect this involves having to add the CPU ID to each 
> packet).

i actually think that the notion of "stopping all system state" is 
rather intuitive from a debugging POV: when you have a bug trigger 
somewhere then getting an NMI to all CPUs and stopping them dead in 
their tracks preserves us the system in its most useful state.

also, when using kgdb to "look at system state" it's best to have as 
little "unrelated" activity as possible.

the timeout argument brought up by Andi was IMO really just pulled here 
by its hair, it never happened to me in practice and i was surprised it 
even came up. (i never before saw "KGDB roundup" fail - and i tried it 
on an 8-way system too) I think the memory-access routine cleanups were 
far more interesting from a failure scenario POV. Maybe Andrew could 
shed some light on his experience and preference here - he's been using 
KGDB for many years.

	Ingo

Re: [git pull] kgdb-light -v10

[Ingo Molnar]

* Ingo Molnar <mingo@elte.hu> wrote:

> > In other words, is it perhaps possible to just *get*rid*of* that 
> > "kgdb_active" and "nmicallback" and the whole multi-CPU roundup? 
> > Just use a kgdb spinlock around the stuff that actually sends and 
> > receives individual packets, and expect the debugger side to sort 
> > them out (yeah, I suspect this involves having to add the CPU ID to 
> > each packet).
> 
> i actually think that the notion of "stopping all system state" is 
> rather intuitive from a debugging POV: when you have a bug trigger 
> somewhere then getting an NMI to all CPUs and stopping them dead in 
> their tracks preserves us the system in its most useful state.

on a second thought - i actually think it's rather possible and 
straightforward to do what you suggest. Stopping of all CPUs is still 
useful, but should be an optional property. I'll play with this a bit 
and see how GDB reacts.

	Ingo

Re: [git pull] kgdb-light -v10

[Andi Kleen]

>  - the kgdb commands should always act on the *current* CPU only
>  - add one command that says "switch over to CPU #n" which just releases 
>    the current CPU and sends an IPI to that CPU #n (no timeouts, no 
>    synchronous waiting, no nothing - it's like a "continue", but with a 
>    "try to get the other CPU to stop"

The problem I see here is that the kernel tends to get badly confused
if one CPU just stops responding. At some point someone does an global
IPI and that then hangs.  You would need to hotunplug the CPU which
is theoretically possible, but quite intrusive. Or maybe the "isolate CPUs 
in cpusets" frame work someone posted recently on l-k could be used.  Still 
would probably have all kinds of tricky issues and races.

-Andi

Re: [git pull] kgdb-light -v10

[Linus Torvalds]

On Tue, 12 Feb 2008, Andi Kleen wrote:
>
> >  - the kgdb commands should always act on the *current* CPU only
> >  - add one command that says "switch over to CPU #n" which just releases 
> >    the current CPU and sends an IPI to that CPU #n (no timeouts, no 
> >    synchronous waiting, no nothing - it's like a "continue", but with a 
> >    "try to get the other CPU to stop"
> 
> The problem I see here is that the kernel tends to get badly confused
> if one CPU just stops responding. At some point someone does an global
> IPI and that then hangs.  You would need to hotunplug the CPU which
> is theoretically possible, but quite intrusive.

You're thinking about this totally *wrong*.

You definitely do not want to hot-unplug or isolate anything at all. 
That's explicitly against the whole point of kgdb not changing what it is 
trying to measure.

Just let the other CPU's hang naturally if they need to wait for IPI's 
etc. What's the downside? That's what you were trying to do in the first 
place by havign the kgdb callback!

So you can't have it both ways. Either serializing other cpu's with kgdb 
is good (the whole "kgdb_nmicallback" thing or whatever it was called), in 
which case it's also perfectly ok to just let them stop when waiting for 
IPI's.

My point was *not* that kgdb should take control of one CPU, and the other 
CPU's should continue to work as if nothing happened. That is insane and 
impossible (since you may be stopping a CPU while it holds central 
spinlocks etc). No, my point was that I think kgdb should be as light and 
non-intrusive as possible, and that any "higher level behaviour" (like the 
decision of whether to try to synchronize other CPU's or not) should be 
left to the debugger.

But only if that makes kgdb patches less intrusive!

In other words, I'm not at all trying to push any particular solution 
here, except for the "keep it simple, and anything even remotely debatable 
or intrusive to the system should be excised". And I wanted to point out 
that maybe all these timeout etc decisions can be pushed to the debugger.

So I think we can either:

 - have no timeouts or other fancy crap _at_all_, with very simple locking 
   (ie looks what v10 mostly seems to do)

 - or you do the fancy dance entirely in the remote debugger.

I don't care. The only thing I care about is that kgdb support never 
_ever_ shows up in any interesting code, and that it remains totally 
invisible to essentially all of the kernel except the place that would 
otherwise print out an oops.

And I absolutely don't want it to be fancy, I want it to be so simple that 
even _I_ can look at it and say "I think this is crap, but it's _trivial_ 
crap".

IOW: as long as people keep arguing about it, I sure as hell won't ever 
merge it. It needs to be so _obvious_ and so _minimal_ that I can feel 
that I finally don't need to care.

			Linus

Re: [git pull] kgdb-light -v10

[Andi Kleen]

On Tue, Feb 12, 2008 at 10:11:13AM -0800, Linus Torvalds wrote:
> 
> 
> On Tue, 12 Feb 2008, Andi Kleen wrote:
> >
> > >  - the kgdb commands should always act on the *current* CPU only
> > >  - add one command that says "switch over to CPU #n" which just releases 
> > >    the current CPU and sends an IPI to that CPU #n (no timeouts, no 
> > >    synchronous waiting, no nothing - it's like a "continue", but with a 
> > >    "try to get the other CPU to stop"
> > 
> > The problem I see here is that the kernel tends to get badly confused
> > if one CPU just stops responding. At some point someone does an global
> > IPI and that then hangs.  You would need to hotunplug the CPU which
> > is theoretically possible, but quite intrusive.
> 
> You're thinking about this totally *wrong*.
> 
> You definitely do not want to hot-unplug or isolate anything at all. 

I agree that it wouldn't be a good idea -- i was just pointing out
consequences of your proposal.

> Just let the other CPU's hang naturally if they need to wait for IPI's 
> etc. What's the downside?

There tend to be timeouts (e.g. softlock/nmi watchdog at least). I think
some of the IPIs eventually time out too.  In general losing a lot 
of time can lead to weird side effects.

-Andi

Re: [git pull] kgdb-light -v10

[Linus Torvalds]

On Tue, 12 Feb 2008, Andi Kleen wrote:
> 
> There tend to be timeouts (e.g. softlock/nmi watchdog at least). I think
> some of the IPIs eventually time out too.  In general losing a lot 
> of time can lead to weird side effects.

I do agree that kgdb and watchdogs aren't like to work well together. And 
I don't think you can sanely expect to not have a "disable lockup 
detection" when you start poking around with kgdb.

We also just have to expect that time will also stop while sometbody is 
messing around with kgdb.

So I don't dispute that any kernel debugger will *always* be intrusive in 
those ways. That's pretty inevitable. I just think the code itself can try 
to avoid hooking into various places all over the map.

			Linus

Re: [git pull] kgdb-light -v10

[Andrew Morton]

On Tue, 12 Feb 2008 19:20:24 +0100 Andi Kleen <andi@firstfloor.org> wrote:

> >  - the kgdb commands should always act on the *current* CPU only
> >  - add one command that says "switch over to CPU #n" which just releases 
> >    the current CPU and sends an IPI to that CPU #n (no timeouts, no 
> >    synchronous waiting, no nothing - it's like a "continue", but with a 
> >    "try to get the other CPU to stop"
> 
> The problem I see here is that the kernel tends to get badly confused
> if one CPU just stops responding. At some point someone does an global
> IPI and that then hangs.

Yes.  A stopped CPU is very visible and hence can change the behaviour of
the system which is being tested.

>  You would need to hotunplug the CPU which
> is theoretically possible, but quite intrusive. Or maybe the "isolate CPUs 
> in cpusets" frame work someone posted recently on l-k could be used.  Still 
> would probably have all kinds of tricky issues and races.

I don't think you'd want to be poking around in kernel internals while some
of the CPUs are continuing to run.  It sounds rather creepy.  You want
everything to stop.  Including time-related things.

Bear in mind that one of the things you do with kgdb is to modify kernel
memory - I'd do things like

int foo;

	...
	if (foo == 1)
		special_stuff();
	...

to trigger a particular behaviour at a particular time.  If you're making
multiple changes, you want them "atomic" wrt all CPUs.  (Of course, if you
happeed to breakpoint one CPU while it was partway through reading multiple
locations, you lose.  But that's a teeny window).



OT: another thing you can do with kgdb is error-path testing:

	foo = kmalloc(...)
BP->	if (!foo)
		recover();

put a breakpoint on the !foo test and set foo to zero by hand.

Re: [git pull] kgdb-light -v10

[Andi Kleen]

On Tue, Feb 12, 2008 at 10:20:10AM -0800, Andrew Morton wrote:
> On Tue, 12 Feb 2008 19:20:24 +0100 Andi Kleen <andi@firstfloor.org> wrote:
> 
> > >  - the kgdb commands should always act on the *current* CPU only
> > >  - add one command that says "switch over to CPU #n" which just releases 
> > >    the current CPU and sends an IPI to that CPU #n (no timeouts, no 
> > >    synchronous waiting, no nothing - it's like a "continue", but with a 
> > >    "try to get the other CPU to stop"
> > 
> > The problem I see here is that the kernel tends to get badly confused
> > if one CPU just stops responding. At some point someone does an global
> > IPI and that then hangs.
> 
> Yes.  A stopped CPU is very visible and hence can change the behaviour of
> the system which is being tested.
> 
> >  You would need to hotunplug the CPU which
> > is theoretically possible, but quite intrusive. Or maybe the "isolate CPUs 
> > in cpusets" frame work someone posted recently on l-k could be used.  Still 
> > would probably have all kinds of tricky issues and races.
> 
> I don't think you'd want to be poking around in kernel internals while some
> of the CPUs are continuing to run.  It sounds rather creepy.  You want
> everything to stop.  Including time-related things.

Note I wrote the one above only as a reply to Linus' proposal, not
because I was advocating "live debugging" (or rather I think if you want
that just use gdb vmlinux /proc/kcore) 

I agree with you in principle, but what do you do if one of the CPUs doesn't 
answer? 

Ingo seems to think it's ok for the debugger then to just hang too,
I think it should eventually time out and debug anyways.

Also there are some limits on how much the system should be frozen
down. For example if you're strict about this requirement you
would need to require full DMA quiescence (like kexec does). But that's
obvious not a good idea for the debugger. So it's always shades
of gray, not black/white.

What I find strange with the current patch is that it goes to extreme
measures to stop the CPUs (will hang forever), but not do the whole
thing (DMA quiescence too) 

-Andi

Re: [git pull] kgdb-light -v10

[Ingo Molnar]

* Andi Kleen <andi@firstfloor.org> wrote:

> I agree with you in principle, but what do you do if one of the CPUs 
> doesn't answer?
> 
> Ingo seems to think it's ok for the debugger then to just hang too, I 
> think it should eventually time out and debug anyways.

Andi, please refrain from misrepresenting my position, i can speak for 
myself.

As i stated it before, i'm not against adding some configuration on 
roundup behavior as long as it's clearly add-on optional system policy. 
In fact i already implemented that in the kgdb-light tree.

But if your goal is to create smoke where there is none, then feel free 
to continue to beat down on this poor strawman, ok? ;-) Meanwhile we'll 
continue to clean up kgdb to make it ready for an eventual (and IMO well 
deserved) .26 merge. All the useful bits of your comments have made kgdb 
cleaner - thanks for that. But please lets keep this constructive. 
Thanks,

	Ingo

Re: [git pull] kgdb-light -v10

[Frank Ch. Eigler]

Hi -

On Tue, Feb 12, 2008 at 10:20:10AM -0800, Andrew Morton wrote:
> [...]  Bear in mind that one of the things you do with kgdb is to
> modify kernel memory [...]

Just for completeness, keep in mind that one can already 
do these sorts of things on a batch basis using systemtap:


> int foo;
> 	...
> 	if (foo == 1)
> 		special_stuff();
> 	...
> 
> to trigger a particular behaviour at a particular time.  [...]

If "foo" is a global within a particular compliation unit, any old
function in that CU can be probed to set/get the global.  (Setting
incoming function parameters works too.)

# cat delayed-set.stp
   # set a systemtap script variable based on a /proc control file
   probe procfs("activate").write { setit = $value }
   global setit
   # check the systemtap global in order to set the kernel global
   probe kernel.function("foo_checking_fn") { 
      if (setit=="1") { setit = ""; $foo = 1 }
   }
# stap -g -m ds delayed-set.stp &
# echo 1 > /proc/systemtap/ds/activate


> OT: another thing you can do with kgdb is error-path testing:
> 	foo = kmalloc(...)
> BP->	if (!foo)
> 		recover();
> put a breakpoint on the !foo test and set foo to zero by hand.

# cat setit2.stp
  probe kernel.statement("*@dir/function.c:222") { /*if (desired)*/ $foo = 0 }
# stap -g setit2.stp &


- FChE

Re: [git pull] kgdb-light -v10

[Andi Kleen]

On Tue, Feb 12, 2008 at 02:34:51PM -0500, Frank Ch. Eigler wrote:
> Hi -
> 
> On Tue, Feb 12, 2008 at 10:20:10AM -0800, Andrew Morton wrote:
> > [...]  Bear in mind that one of the things you do with kgdb is to
> > modify kernel memory [...]
> 
> Just for completeness, keep in mind that one can already 
> do these sorts of things on a batch basis using systemtap:

You don't even need systemtap: it has been always possible with
gdb -write vmlinux /proc/kcore

The only value add of the kgdb stub is really that you can single
step too and do post mortem (although the later works fine using
kdump/crash these days too)

-Andi

Re: [git pull] kgdb-light -v10

[Domenico Andreoli]

Hi,

On Tue, Feb 12, 2008 at 12:27:47PM +0100, Ingo Molnar wrote:
> 
> this is kgdb-light, version -v10 (against Linus-latest), and can be 
> pulled from:
> 
>    git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-kgdb.git
> 
> shortlog, diffstat and full patch can be found further below.

  I am just trying to play with this, I am not able to make it work.
Assume I am able with git, I use it every day on my software, then I
am correctly tracking and building your branch on git.kernel.org.

My config has both KGDB and KGDB_SERIAL_CONSOLE. kernel command line
has kgdbwait kgdboc=ttyS0,115200. linux console is not on serial but if
do not enable KGDB_SERIAL_CONSOLE I am then unable to hit SysRq+g. If
instead I use linux serial console, gdb messes with getty and things
quickly get worse.

1. at boot, kernel waits for a gdb connection
2. gdb connection is established from another box
3. gdb breaks in
4. hit continue at gdb prompt
5. target box returns to life. everything looks ok (it is 2.6.25-rc1!)
6. SysRq+h on the target correctly shows the help on the console
7. SysRq+g on the target, it prints "SysRq : GDB" and hangs forever
8. gdb on the host does not break in

is really that simple, am i overlooking anything? thank you.

regards,
Domenico

#
# Automatically generated make config: don't edit
# Linux kernel version: 2.6.25-rc1
# Mon Feb 11 11:34:22 2008
#
CONFIG_PARISC=y
CONFIG_MMU=y
CONFIG_STACK_GROWSUP=y
CONFIG_RWSEM_GENERIC_SPINLOCK=y
# CONFIG_ARCH_HAS_ILOG2_U32 is not set
# CONFIG_ARCH_HAS_ILOG2_U64 is not set
CONFIG_GENERIC_FIND_NEXT_BIT=y
CONFIG_GENERIC_BUG=y
CONFIG_GENERIC_HWEIGHT=y
CONFIG_GENERIC_CALIBRATE_DELAY=y
CONFIG_GENERIC_TIME=y
CONFIG_TIME_LOW_RES=y
CONFIG_GENERIC_HARDIRQS=y
CONFIG_GENERIC_IRQ_PROBE=y
CONFIG_IRQ_PER_CPU=y
CONFIG_ARCH_SUPPORTS_AOUT=y
CONFIG_DEFCONFIG_LIST="/lib/modules/$UNAME_RELEASE/.config"

#
# General setup
#
CONFIG_EXPERIMENTAL=y
CONFIG_LOCK_KERNEL=y
CONFIG_INIT_ENV_ARG_LIMIT=32
CONFIG_LOCALVERSION=""
CONFIG_LOCALVERSION_AUTO=y
CONFIG_SWAP=y
CONFIG_SYSVIPC=y
CONFIG_SYSVIPC_SYSCTL=y
CONFIG_POSIX_MQUEUE=y
# CONFIG_BSD_PROCESS_ACCT is not set
# CONFIG_TASKSTATS is not set
# CONFIG_AUDIT is not set
CONFIG_IKCONFIG=y
# CONFIG_IKCONFIG_PROC is not set
CONFIG_LOG_BUF_SHIFT=15
# CONFIG_CGROUPS is not set
CONFIG_FAIR_GROUP_SCHED=y
CONFIG_FAIR_USER_SCHED=y
# CONFIG_FAIR_CGROUP_SCHED is not set
CONFIG_SYSFS_DEPRECATED=y
# CONFIG_RELAY is not set
CONFIG_NAMESPACES=y
# CONFIG_UTS_NS is not set
# CONFIG_IPC_NS is not set
# CONFIG_USER_NS is not set
# CONFIG_PID_NS is not set
# CONFIG_BLK_DEV_INITRD is not set
# CONFIG_CC_OPTIMIZE_FOR_SIZE is not set
CONFIG_SYSCTL=y
# CONFIG_EMBEDDED is not set
CONFIG_SYSCTL_SYSCALL=y
CONFIG_KALLSYMS=y
# CONFIG_KALLSYMS_ALL is not set
# CONFIG_KALLSYMS_EXTRA_PASS is not set
CONFIG_HOTPLUG=y
CONFIG_PRINTK=y
CONFIG_BUG=y
CONFIG_ELF_CORE=y
CONFIG_COMPAT_BRK=y
CONFIG_BASE_FULL=y
CONFIG_FUTEX=y
CONFIG_ANON_INODES=y
CONFIG_EPOLL=y
CONFIG_SIGNALFD=y
CONFIG_TIMERFD=y
CONFIG_EVENTFD=y
CONFIG_SHMEM=y
CONFIG_VM_EVENT_COUNTERS=y
CONFIG_SLUB_DEBUG=y
# CONFIG_SLAB is not set
CONFIG_SLUB=y
# CONFIG_SLOB is not set
# CONFIG_PROFILING is not set
# CONFIG_MARKERS is not set
CONFIG_HAVE_OPROFILE=y
# CONFIG_HAVE_KPROBES is not set
CONFIG_PROC_PAGE_MONITOR=y
CONFIG_SLABINFO=y
CONFIG_RT_MUTEXES=y
# CONFIG_TINY_SHMEM is not set
CONFIG_BASE_SMALL=0
CONFIG_MODULES=y
CONFIG_MODULE_UNLOAD=y
CONFIG_MODULE_FORCE_UNLOAD=y
CONFIG_MODVERSIONS=y
# CONFIG_MODULE_SRCVERSION_ALL is not set
CONFIG_KMOD=y
CONFIG_STOP_MACHINE=y
CONFIG_BLOCK=y
# CONFIG_BLK_DEV_IO_TRACE is not set
# CONFIG_BLK_DEV_BSG is not set
CONFIG_BLOCK_COMPAT=y

#
# IO Schedulers
#
CONFIG_IOSCHED_NOOP=y
CONFIG_IOSCHED_AS=y
CONFIG_IOSCHED_DEADLINE=y
CONFIG_IOSCHED_CFQ=y
# CONFIG_DEFAULT_AS is not set
# CONFIG_DEFAULT_DEADLINE is not set
CONFIG_DEFAULT_CFQ=y
# CONFIG_DEFAULT_NOOP is not set
CONFIG_DEFAULT_IOSCHED="cfq"
CONFIG_CLASSIC_RCU=y
# CONFIG_PREEMPT_RCU is not set

#
# Processor type and features
#
# CONFIG_PA7000 is not set
# CONFIG_PA7100LC is not set
# CONFIG_PA7200 is not set
# CONFIG_PA7300LC is not set
CONFIG_PA8X00=y
CONFIG_PA20=y
CONFIG_PREFETCH=y
CONFIG_64BIT=y
CONFIG_PARISC_PAGE_SIZE_4KB=y
# CONFIG_PARISC_PAGE_SIZE_16KB is not set
# CONFIG_PARISC_PAGE_SIZE_64KB is not set
CONFIG_SMP=y
CONFIG_HOTPLUG_CPU=y
CONFIG_ARCH_SELECT_MEMORY_MODEL=y
CONFIG_ARCH_DISCONTIGMEM_ENABLE=y
CONFIG_ARCH_FLATMEM_ENABLE=y
CONFIG_ARCH_DISCONTIGMEM_DEFAULT=y
CONFIG_PREEMPT_NONE=y
# CONFIG_PREEMPT_VOLUNTARY is not set
# CONFIG_PREEMPT is not set
CONFIG_RCU_TRACE=y
CONFIG_HZ_100=y
# CONFIG_HZ_250 is not set
# CONFIG_HZ_300 is not set
# CONFIG_HZ_1000 is not set
CONFIG_HZ=100
# CONFIG_SCHED_HRTICK is not set
CONFIG_SELECT_MEMORY_MODEL=y
CONFIG_FLATMEM_MANUAL=y
# CONFIG_DISCONTIGMEM_MANUAL is not set
# CONFIG_SPARSEMEM_MANUAL is not set
CONFIG_FLATMEM=y
CONFIG_FLAT_NODE_MEM_MAP=y
# CONFIG_SPARSEMEM_STATIC is not set
# CONFIG_SPARSEMEM_VMEMMAP_ENABLE is not set
CONFIG_SPLIT_PTLOCK_CPUS=4
CONFIG_RESOURCES_64BIT=y
CONFIG_ZONE_DMA_FLAG=0
CONFIG_VIRT_TO_BUS=y
CONFIG_COMPAT=y
CONFIG_NR_CPUS=2

#
# Bus options (PCI, PCMCIA, EISA, GSC, ISA)
#
CONFIG_GSC=y
CONFIG_HPPB=y
CONFIG_IOMMU_CCIO=y
CONFIG_GSC_LASI=y
CONFIG_GSC_WAX=y
CONFIG_EISA=y
CONFIG_EISA_NAMES=y
CONFIG_ISA=y
CONFIG_PCI=y
# CONFIG_ARCH_SUPPORTS_MSI is not set
CONFIG_PCI_LEGACY=y
# CONFIG_PCI_DEBUG is not set
CONFIG_GSC_DINO=y
CONFIG_PCI_LBA=y
CONFIG_IOSAPIC=y
CONFIG_IOMMU_SBA=y
# CONFIG_PCCARD is not set
# CONFIG_HOTPLUG_PCI is not set

#
# PA-RISC specific drivers
#
CONFIG_SUPERIO=y
CONFIG_CHASSIS_LCD_LED=y
CONFIG_PDC_CHASSIS=y
CONFIG_PDC_CHASSIS_WARN=y
CONFIG_PDC_STABLE=y

#
# Executable file formats
#
CONFIG_BINFMT_ELF=y
# CONFIG_BINFMT_MISC is not set

#
# Networking
#
CONFIG_NET=y

#
# Networking options
#
CONFIG_PACKET=y
CONFIG_PACKET_MMAP=y
CONFIG_UNIX=y
# CONFIG_NET_KEY is not set
CONFIG_INET=y
# CONFIG_IP_MULTICAST is not set
# CONFIG_IP_ADVANCED_ROUTER is not set
CONFIG_IP_FIB_HASH=y
# CONFIG_IP_PNP is not set
# CONFIG_NET_IPIP is not set
# CONFIG_NET_IPGRE is not set
# CONFIG_ARPD is not set
# CONFIG_SYN_COOKIES is not set
# CONFIG_INET_AH is not set
# CONFIG_INET_ESP is not set
# CONFIG_INET_IPCOMP is not set
# CONFIG_INET_XFRM_TUNNEL is not set
# CONFIG_INET_TUNNEL is not set
# CONFIG_INET_XFRM_MODE_TRANSPORT is not set
# CONFIG_INET_XFRM_MODE_TUNNEL is not set
# CONFIG_INET_XFRM_MODE_BEET is not set
# CONFIG_INET_LRO is not set
CONFIG_INET_DIAG=m
CONFIG_INET_TCP_DIAG=m
# CONFIG_TCP_CONG_ADVANCED is not set
CONFIG_TCP_CONG_CUBIC=y
CONFIG_DEFAULT_TCP_CONG="cubic"
# CONFIG_TCP_MD5SIG is not set
# CONFIG_IP_VS is not set
# CONFIG_IPV6 is not set
# CONFIG_INET6_XFRM_TUNNEL is not set
# CONFIG_INET6_TUNNEL is not set
# CONFIG_NETLABEL is not set
# CONFIG_NETWORK_SECMARK is not set
CONFIG_NETFILTER=y
# CONFIG_NETFILTER_DEBUG is not set
# CONFIG_NETFILTER_ADVANCED is not set

#
# Core Netfilter Configuration
#
# CONFIG_NETFILTER_NETLINK_LOG is not set
CONFIG_NF_CONNTRACK=y
# CONFIG_NF_CONNTRACK_FTP is not set
# CONFIG_NF_CONNTRACK_IRC is not set
# CONFIG_NF_CONNTRACK_SIP is not set
# CONFIG_NF_CT_NETLINK is not set
CONFIG_NETFILTER_XTABLES=m
# CONFIG_NETFILTER_XT_TARGET_MARK is not set
# CONFIG_NETFILTER_XT_TARGET_NFLOG is not set
# CONFIG_NETFILTER_XT_TARGET_TCPMSS is not set
# CONFIG_NETFILTER_XT_MATCH_CONNTRACK is not set
# CONFIG_NETFILTER_XT_MATCH_MARK is not set
# CONFIG_NETFILTER_XT_MATCH_STATE is not set

#
# IP: Netfilter Configuration
#
CONFIG_NF_CONNTRACK_IPV4=m
CONFIG_NF_CONNTRACK_PROC_COMPAT=y
CONFIG_IP_NF_IPTABLES=m
CONFIG_IP_NF_FILTER=m
CONFIG_IP_NF_TARGET_REJECT=m
CONFIG_IP_NF_TARGET_LOG=m
CONFIG_IP_NF_TARGET_ULOG=m
CONFIG_NF_NAT=m
CONFIG_NF_NAT_NEEDED=y
CONFIG_IP_NF_TARGET_MASQUERADE=m
# CONFIG_NF_NAT_FTP is not set
# CONFIG_NF_NAT_IRC is not set
# CONFIG_NF_NAT_TFTP is not set
# CONFIG_NF_NAT_AMANDA is not set
# CONFIG_NF_NAT_PPTP is not set
# CONFIG_NF_NAT_H323 is not set
# CONFIG_NF_NAT_SIP is not set
CONFIG_IP_NF_MANGLE=m
# CONFIG_IP_DCCP is not set
# CONFIG_IP_SCTP is not set
# CONFIG_TIPC is not set
# CONFIG_ATM is not set
# CONFIG_BRIDGE is not set
# CONFIG_VLAN_8021Q is not set
# CONFIG_DECNET is not set
# CONFIG_LLC2 is not set
# CONFIG_IPX is not set
# CONFIG_ATALK is not set
# CONFIG_X25 is not set
# CONFIG_LAPB is not set
# CONFIG_ECONET is not set
# CONFIG_WAN_ROUTER is not set
# CONFIG_NET_SCHED is not set

#
# Network testing
#
# CONFIG_NET_PKTGEN is not set
# CONFIG_HAMRADIO is not set
# CONFIG_CAN is not set
# CONFIG_IRDA is not set
# CONFIG_BT is not set
# CONFIG_AF_RXRPC is not set

#
# Wireless
#
CONFIG_CFG80211=m
CONFIG_NL80211=y
CONFIG_WIRELESS_EXT=y
# CONFIG_MAC80211 is not set
CONFIG_IEEE80211=m
# CONFIG_IEEE80211_DEBUG is not set
CONFIG_IEEE80211_CRYPT_WEP=m
CONFIG_IEEE80211_CRYPT_CCMP=m
CONFIG_IEEE80211_CRYPT_TKIP=m
CONFIG_IEEE80211_SOFTMAC=m
# CONFIG_IEEE80211_SOFTMAC_DEBUG is not set
# CONFIG_RFKILL is not set
# CONFIG_NET_9P is not set

#
# Device Drivers
#

#
# Generic Driver Options
#
CONFIG_UEVENT_HELPER_PATH="/sbin/hotplug"
CONFIG_STANDALONE=y
CONFIG_PREVENT_FIRMWARE_BUILD=y
CONFIG_FW_LOADER=m
# CONFIG_DEBUG_DRIVER is not set
# CONFIG_DEBUG_DEVRES is not set
# CONFIG_SYS_HYPERVISOR is not set
# CONFIG_CONNECTOR is not set
# CONFIG_MTD is not set
# CONFIG_PARPORT is not set
# CONFIG_PNP is not set
CONFIG_BLK_DEV=y
# CONFIG_BLK_CPQ_DA is not set
# CONFIG_BLK_CPQ_CISS_DA is not set
# CONFIG_BLK_DEV_DAC960 is not set
# CONFIG_BLK_DEV_UMEM is not set
# CONFIG_BLK_DEV_COW_COMMON is not set
CONFIG_BLK_DEV_LOOP=m
CONFIG_BLK_DEV_CRYPTOLOOP=m
# CONFIG_BLK_DEV_NBD is not set
# CONFIG_BLK_DEV_SX8 is not set
CONFIG_BLK_DEV_RAM=y
CONFIG_BLK_DEV_RAM_COUNT=16
CONFIG_BLK_DEV_RAM_SIZE=8192
# CONFIG_BLK_DEV_XIP is not set
# CONFIG_CDROM_PKTCDVD is not set
# CONFIG_ATA_OVER_ETH is not set
CONFIG_MISC_DEVICES=y
# CONFIG_PHANTOM is not set
# CONFIG_EEPROM_93CX6 is not set
CONFIG_SGI_IOC4=m
CONFIG_TIFM_CORE=m
CONFIG_TIFM_7XX1=m
# CONFIG_ENCLOSURE_SERVICES is not set
CONFIG_HAVE_IDE=y
# CONFIG_IDE is not set

#
# SCSI device support
#
CONFIG_RAID_ATTRS=y
CONFIG_SCSI=y
CONFIG_SCSI_DMA=y
CONFIG_SCSI_TGT=y
# CONFIG_SCSI_NETLINK is not set
# CONFIG_SCSI_PROC_FS is not set

#
# SCSI support type (disk, tape, CD-ROM)
#
CONFIG_BLK_DEV_SD=y
# CONFIG_CHR_DEV_ST is not set
# CONFIG_CHR_DEV_OSST is not set
# CONFIG_BLK_DEV_SR is not set
# CONFIG_CHR_DEV_SG is not set
# CONFIG_CHR_DEV_SCH is not set

#
# Some SCSI devices (e.g. CD jukebox) support multiple LUNs
#
CONFIG_SCSI_MULTI_LUN=y
CONFIG_SCSI_CONSTANTS=y
CONFIG_SCSI_LOGGING=y
# CONFIG_SCSI_SCAN_ASYNC is not set
CONFIG_SCSI_WAIT_SCAN=m

#
# SCSI Transports
#
CONFIG_SCSI_SPI_ATTRS=y
# CONFIG_SCSI_FC_ATTRS is not set
# CONFIG_SCSI_ISCSI_ATTRS is not set
# CONFIG_SCSI_SAS_LIBSAS is not set
# CONFIG_SCSI_SRP_ATTRS is not set
CONFIG_SCSI_LOWLEVEL=y
# CONFIG_ISCSI_TCP is not set
# CONFIG_BLK_DEV_3W_XXXX_RAID is not set
# CONFIG_SCSI_3W_9XXX is not set
# CONFIG_SCSI_ACARD is not set
# CONFIG_SCSI_AHA1740 is not set
# CONFIG_SCSI_AACRAID is not set
# CONFIG_SCSI_AIC7XXX is not set
# CONFIG_SCSI_AIC7XXX_OLD is not set
# CONFIG_SCSI_AIC79XX is not set
# CONFIG_SCSI_AIC94XX is not set
# CONFIG_SCSI_ADVANSYS is not set
# CONFIG_SCSI_IN2000 is not set
# CONFIG_SCSI_ARCMSR is not set
# CONFIG_MEGARAID_NEWGEN is not set
# CONFIG_MEGARAID_LEGACY is not set
# CONFIG_MEGARAID_SAS is not set
# CONFIG_SCSI_HPTIOP is not set
# CONFIG_SCSI_DMX3191D is not set
# CONFIG_SCSI_DTC3280 is not set
# CONFIG_SCSI_FUTURE_DOMAIN is not set
# CONFIG_SCSI_GENERIC_NCR5380 is not set
# CONFIG_SCSI_GENERIC_NCR5380_MMIO is not set
# CONFIG_SCSI_IPS is not set
# CONFIG_SCSI_INITIO is not set
# CONFIG_SCSI_INIA100 is not set
# CONFIG_SCSI_NCR53C406A is not set
# CONFIG_SCSI_LASI700 is not set
# CONFIG_SCSI_STEX is not set
CONFIG_SCSI_SYM53C8XX_2=y
CONFIG_SCSI_SYM53C8XX_DMA_ADDRESSING_MODE=1
CONFIG_SCSI_SYM53C8XX_DEFAULT_TAGS=16
CONFIG_SCSI_SYM53C8XX_MAX_TAGS=64
CONFIG_SCSI_SYM53C8XX_MMIO=y
# CONFIG_SCSI_ZALON is not set
# CONFIG_SCSI_PAS16 is not set
# CONFIG_SCSI_QLOGIC_FAS is not set
# CONFIG_SCSI_QLOGIC_1280 is not set
# CONFIG_SCSI_QLA_FC is not set
# CONFIG_SCSI_QLA_ISCSI is not set
# CONFIG_SCSI_LPFC is not set
# CONFIG_SCSI_SIM710 is not set
# CONFIG_SCSI_SYM53C416 is not set
# CONFIG_SCSI_DC395x is not set
# CONFIG_SCSI_DC390T is not set
# CONFIG_SCSI_T128 is not set
# CONFIG_SCSI_DEBUG is not set
# CONFIG_SCSI_SRP is not set
# CONFIG_ATA is not set
# CONFIG_MD is not set
# CONFIG_FUSION is not set

#
# IEEE 1394 (FireWire) support
#
# CONFIG_FIREWIRE is not set
# CONFIG_IEEE1394 is not set
# CONFIG_I2O is not set
CONFIG_NETDEVICES=y
# CONFIG_NETDEVICES_MULTIQUEUE is not set
# CONFIG_DUMMY is not set
# CONFIG_BONDING is not set
# CONFIG_MACVLAN is not set
# CONFIG_EQUALIZER is not set
CONFIG_TUN=m
# CONFIG_VETH is not set
# CONFIG_ARCNET is not set
CONFIG_PHYLIB=m

#
# MII PHY device drivers
#
CONFIG_MARVELL_PHY=m
CONFIG_DAVICOM_PHY=m
CONFIG_QSEMI_PHY=m
CONFIG_LXT_PHY=m
CONFIG_CICADA_PHY=m
CONFIG_VITESSE_PHY=m
CONFIG_SMSC_PHY=m
CONFIG_BROADCOM_PHY=m
# CONFIG_ICPLUS_PHY is not set
# CONFIG_REALTEK_PHY is not set
# CONFIG_FIXED_PHY is not set
# CONFIG_MDIO_BITBANG is not set
CONFIG_NET_ETHERNET=y
CONFIG_MII=y
# CONFIG_LASI_82596 is not set
# CONFIG_HAPPYMEAL is not set
# CONFIG_SUNGEM is not set
# CONFIG_CASSINI is not set
CONFIG_NET_VENDOR_3COM=y
# CONFIG_EL1 is not set
# CONFIG_EL2 is not set
# CONFIG_EL16 is not set
# CONFIG_EL3 is not set
CONFIG_VORTEX=y
# CONFIG_TYPHOON is not set
# CONFIG_NET_VENDOR_SMC is not set
# CONFIG_NET_VENDOR_RACAL is not set
CONFIG_NET_TULIP=y
# CONFIG_DE2104X is not set
CONFIG_TULIP=y
# CONFIG_TULIP_MWI is not set
CONFIG_TULIP_MMIO=y
CONFIG_TULIP_NAPI=y
CONFIG_TULIP_NAPI_HW_MITIGATION=y
# CONFIG_DE4X5 is not set
# CONFIG_WINBOND_840 is not set
# CONFIG_DM9102 is not set
# CONFIG_ULI526X is not set
# CONFIG_AT1700 is not set
# CONFIG_DEPCA is not set
# CONFIG_HP100 is not set
# CONFIG_NET_ISA is not set
# CONFIG_IBM_NEW_EMAC_ZMII is not set
# CONFIG_IBM_NEW_EMAC_RGMII is not set
# CONFIG_IBM_NEW_EMAC_TAH is not set
# CONFIG_IBM_NEW_EMAC_EMAC4 is not set
# CONFIG_NET_PCI is not set
# CONFIG_B44 is not set
# CONFIG_NETDEV_1000 is not set
# CONFIG_NETDEV_10000 is not set
# CONFIG_TR is not set

#
# Wireless LAN
#
CONFIG_WLAN_PRE80211=y
# CONFIG_STRIP is not set
# CONFIG_WAVELAN is not set
CONFIG_WLAN_80211=y
# CONFIG_IPW2100 is not set
CONFIG_IPW2200=m
CONFIG_IPW2200_MONITOR=y
# CONFIG_IPW2200_RADIOTAP is not set
# CONFIG_IPW2200_PROMISCUOUS is not set
CONFIG_IPW2200_QOS=y
# CONFIG_IPW2200_DEBUG is not set
CONFIG_LIBERTAS=m
# CONFIG_LIBERTAS_DEBUG is not set
CONFIG_HERMES=m
# CONFIG_PLX_HERMES is not set
# CONFIG_TMD_HERMES is not set
CONFIG_NORTEL_HERMES=m
# CONFIG_PCI_HERMES is not set
# CONFIG_ATMEL is not set
CONFIG_PRISM54=m
CONFIG_HOSTAP=m
CONFIG_HOSTAP_FIRMWARE=y
# CONFIG_HOSTAP_FIRMWARE_NVRAM is not set
CONFIG_HOSTAP_PLX=m
CONFIG_HOSTAP_PCI=m
CONFIG_BCM43XX=m
CONFIG_BCM43XX_DEBUG=y
CONFIG_BCM43XX_DMA=y
CONFIG_BCM43XX_PIO=y
CONFIG_BCM43XX_DMA_AND_PIO_MODE=y
# CONFIG_BCM43XX_DMA_MODE is not set
# CONFIG_BCM43XX_PIO_MODE is not set
# CONFIG_WAN is not set
# CONFIG_FDDI is not set
# CONFIG_HIPPI is not set
# CONFIG_PPP is not set
# CONFIG_SLIP is not set
# CONFIG_NET_FC is not set
# CONFIG_NETCONSOLE is not set
# CONFIG_NETPOLL is not set
# CONFIG_NET_POLL_CONTROLLER is not set
# CONFIG_ISDN is not set
# CONFIG_PHONE is not set

#
# Input device support
#
CONFIG_INPUT=y
# CONFIG_INPUT_FF_MEMLESS is not set
# CONFIG_INPUT_POLLDEV is not set

#
# Userland interfaces
#
CONFIG_INPUT_MOUSEDEV=y
# CONFIG_INPUT_MOUSEDEV_PSAUX is not set
CONFIG_INPUT_MOUSEDEV_SCREEN_X=1024
CONFIG_INPUT_MOUSEDEV_SCREEN_Y=768
# CONFIG_INPUT_JOYDEV is not set
# CONFIG_INPUT_EVDEV is not set
# CONFIG_INPUT_EVBUG is not set

#
# Input Device Drivers
#
# CONFIG_INPUT_KEYBOARD is not set
# CONFIG_INPUT_MOUSE is not set
# CONFIG_INPUT_JOYSTICK is not set
# CONFIG_INPUT_TABLET is not set
# CONFIG_INPUT_TOUCHSCREEN is not set
# CONFIG_INPUT_MISC is not set

#
# Hardware I/O ports
#
CONFIG_SERIO=y
CONFIG_SERIO_SERPORT=y
# CONFIG_SERIO_GSCPS2 is not set
# CONFIG_HP_SDC is not set
# CONFIG_SERIO_PCIPS2 is not set
# CONFIG_SERIO_RAW is not set
# CONFIG_GAMEPORT is not set

#
# Character devices
#
CONFIG_VT=y
CONFIG_VT_CONSOLE=y
CONFIG_HW_CONSOLE=y
# CONFIG_VT_HW_CONSOLE_BINDING is not set
# CONFIG_SERIAL_NONSTANDARD is not set
# CONFIG_NOZOMI is not set

#
# Serial drivers
#
CONFIG_SERIAL_8250=y
CONFIG_SERIAL_8250_CONSOLE=y
CONFIG_SERIAL_8250_GSC=y
CONFIG_SERIAL_8250_PCI=y
CONFIG_SERIAL_8250_NR_UARTS=16
CONFIG_SERIAL_8250_RUNTIME_UARTS=4
CONFIG_SERIAL_8250_EXTENDED=y
# CONFIG_SERIAL_8250_MANY_PORTS is not set
CONFIG_SERIAL_8250_SHARE_IRQ=y
# CONFIG_SERIAL_8250_DETECT_IRQ is not set
# CONFIG_SERIAL_8250_RSA is not set

#
# Non-8250 serial port support
#
# CONFIG_SERIAL_MUX is not set
CONFIG_PDC_CONSOLE=y
CONFIG_SERIAL_CORE=y
CONFIG_SERIAL_CORE_CONSOLE=y
# CONFIG_SERIAL_JSM is not set
CONFIG_UNIX98_PTYS=y
# CONFIG_LEGACY_PTYS is not set
# CONFIG_IPMI_HANDLER is not set
CONFIG_HW_RANDOM=y
# CONFIG_GEN_RTC is not set
# CONFIG_DTLK is not set
# CONFIG_R3964 is not set
# CONFIG_APPLICOM is not set
# CONFIG_RAW_DRIVER is not set
# CONFIG_TCG_TPM is not set
CONFIG_DEVPORT=y
# CONFIG_I2C is not set

#
# SPI support
#
# CONFIG_SPI is not set
# CONFIG_SPI_MASTER is not set
# CONFIG_W1 is not set
# CONFIG_POWER_SUPPLY is not set
# CONFIG_HWMON is not set
# CONFIG_THERMAL is not set
# CONFIG_WATCHDOG is not set

#
# Sonics Silicon Backplane
#
CONFIG_SSB_POSSIBLE=y
# CONFIG_SSB is not set

#
# Multifunction device drivers
#
# CONFIG_MFD_SM501 is not set

#
# Multimedia devices
#
# CONFIG_VIDEO_DEV is not set
# CONFIG_DVB_CORE is not set
# CONFIG_DAB is not set

#
# Graphics support
#
# CONFIG_AGP is not set
# CONFIG_DRM is not set
# CONFIG_VGASTATE is not set
# CONFIG_VIDEO_OUTPUT_CONTROL is not set
# CONFIG_FB is not set
# CONFIG_BACKLIGHT_LCD_SUPPORT is not set

#
# Display device support
#
# CONFIG_DISPLAY_SUPPORT is not set

#
# Console display driver support
#
CONFIG_DUMMY_CONSOLE=y
CONFIG_DUMMY_CONSOLE_COLUMNS=160
CONFIG_DUMMY_CONSOLE_ROWS=64
CONFIG_STI_CONSOLE=y
# CONFIG_FONTS is not set
CONFIG_FONT_8x8=y
CONFIG_FONT_8x16=y

#
# Sound
#
# CONFIG_SOUND is not set
# CONFIG_HID_SUPPORT is not set
# CONFIG_USB_SUPPORT is not set
# CONFIG_MMC is not set
# CONFIG_MEMSTICK is not set
# CONFIG_NEW_LEDS is not set
# CONFIG_INFINIBAND is not set
# CONFIG_RTC_CLASS is not set

#
# Userspace I/O
#
# CONFIG_UIO is not set

#
# File systems
#
CONFIG_EXT2_FS=y
# CONFIG_EXT2_FS_XATTR is not set
# CONFIG_EXT2_FS_XIP is not set
CONFIG_EXT3_FS=y
# CONFIG_EXT3_FS_XATTR is not set
# CONFIG_EXT4DEV_FS is not set
CONFIG_JBD=y
# CONFIG_JBD_DEBUG is not set
CONFIG_REISERFS_FS=y
# CONFIG_REISERFS_CHECK is not set
# CONFIG_REISERFS_PROC_INFO is not set
# CONFIG_REISERFS_FS_XATTR is not set
# CONFIG_JFS_FS is not set
# CONFIG_FS_POSIX_ACL is not set
# CONFIG_XFS_FS is not set
# CONFIG_GFS2_FS is not set
# CONFIG_OCFS2_FS is not set
# CONFIG_DNOTIFY is not set
# CONFIG_INOTIFY is not set
# CONFIG_QUOTA is not set
# CONFIG_AUTOFS_FS is not set
# CONFIG_AUTOFS4_FS is not set
CONFIG_FUSE_FS=m

#
# CD-ROM/DVD Filesystems
#
CONFIG_ISO9660_FS=m
CONFIG_JOLIET=y
CONFIG_ZISOFS=y
# CONFIG_UDF_FS is not set

#
# DOS/FAT/NT Filesystems
#
CONFIG_FAT_FS=m
CONFIG_MSDOS_FS=m
CONFIG_VFAT_FS=m
CONFIG_FAT_DEFAULT_CODEPAGE=437
CONFIG_FAT_DEFAULT_IOCHARSET="iso8859-1"
# CONFIG_NTFS_FS is not set

#
# Pseudo filesystems
#
CONFIG_PROC_FS=y
CONFIG_PROC_KCORE=y
CONFIG_PROC_SYSCTL=y
CONFIG_SYSFS=y
CONFIG_TMPFS=y
# CONFIG_TMPFS_POSIX_ACL is not set
# CONFIG_HUGETLB_PAGE is not set
CONFIG_CONFIGFS_FS=m

#
# Miscellaneous filesystems
#
# CONFIG_ADFS_FS is not set
# CONFIG_AFFS_FS is not set
# CONFIG_HFS_FS is not set
# CONFIG_HFSPLUS_FS is not set
# CONFIG_BEFS_FS is not set
# CONFIG_BFS_FS is not set
# CONFIG_EFS_FS is not set
# CONFIG_CRAMFS is not set
# CONFIG_VXFS_FS is not set
# CONFIG_MINIX_FS is not set
# CONFIG_HPFS_FS is not set
# CONFIG_QNX4FS_FS is not set
# CONFIG_ROMFS_FS is not set
# CONFIG_SYSV_FS is not set
# CONFIG_UFS_FS is not set
CONFIG_NETWORK_FILESYSTEMS=y
# CONFIG_NFS_FS is not set
# CONFIG_NFSD is not set
# CONFIG_SMB_FS is not set
# CONFIG_CIFS is not set
# CONFIG_NCP_FS is not set
# CONFIG_CODA_FS is not set
# CONFIG_AFS_FS is not set

#
# Partition Types
#
# CONFIG_PARTITION_ADVANCED is not set
CONFIG_MSDOS_PARTITION=y
CONFIG_NLS=y
CONFIG_NLS_DEFAULT="iso8859-1"
CONFIG_NLS_CODEPAGE_437=m
# CONFIG_NLS_CODEPAGE_737 is not set
# CONFIG_NLS_CODEPAGE_775 is not set
CONFIG_NLS_CODEPAGE_850=m
# CONFIG_NLS_CODEPAGE_852 is not set
# CONFIG_NLS_CODEPAGE_855 is not set
# CONFIG_NLS_CODEPAGE_857 is not set
# CONFIG_NLS_CODEPAGE_860 is not set
# CONFIG_NLS_CODEPAGE_861 is not set
# CONFIG_NLS_CODEPAGE_862 is not set
# CONFIG_NLS_CODEPAGE_863 is not set
# CONFIG_NLS_CODEPAGE_864 is not set
# CONFIG_NLS_CODEPAGE_865 is not set
# CONFIG_NLS_CODEPAGE_866 is not set
# CONFIG_NLS_CODEPAGE_869 is not set
# CONFIG_NLS_CODEPAGE_936 is not set
# CONFIG_NLS_CODEPAGE_950 is not set
# CONFIG_NLS_CODEPAGE_932 is not set
# CONFIG_NLS_CODEPAGE_949 is not set
# CONFIG_NLS_CODEPAGE_874 is not set
# CONFIG_NLS_ISO8859_8 is not set
# CONFIG_NLS_CODEPAGE_1250 is not set
# CONFIG_NLS_CODEPAGE_1251 is not set
CONFIG_NLS_ASCII=m
CONFIG_NLS_ISO8859_1=m
# CONFIG_NLS_ISO8859_2 is not set
# CONFIG_NLS_ISO8859_3 is not set
# CONFIG_NLS_ISO8859_4 is not set
# CONFIG_NLS_ISO8859_5 is not set
# CONFIG_NLS_ISO8859_6 is not set
# CONFIG_NLS_ISO8859_7 is not set
# CONFIG_NLS_ISO8859_9 is not set
# CONFIG_NLS_ISO8859_13 is not set
# CONFIG_NLS_ISO8859_14 is not set
CONFIG_NLS_ISO8859_15=m
# CONFIG_NLS_KOI8_R is not set
# CONFIG_NLS_KOI8_U is not set
CONFIG_NLS_UTF8=m
# CONFIG_DLM is not set

#
# Kernel hacking
#
# CONFIG_PRINTK_TIME is not set
CONFIG_ENABLE_WARN_DEPRECATED=y
CONFIG_ENABLE_MUST_CHECK=y
CONFIG_MAGIC_SYSRQ=y
CONFIG_UNUSED_SYMBOLS=y
CONFIG_DEBUG_FS=y
# CONFIG_HEADERS_CHECK is not set
CONFIG_DEBUG_KERNEL=y
# CONFIG_DEBUG_SHIRQ is not set
# CONFIG_DETECT_SOFTLOCKUP is not set
CONFIG_SCHED_DEBUG=y
# CONFIG_SCHEDSTATS is not set
# CONFIG_TIMER_STATS is not set
# CONFIG_SLUB_DEBUG_ON is not set
# CONFIG_SLUB_STATS is not set
# CONFIG_DEBUG_RT_MUTEXES is not set
# CONFIG_RT_MUTEX_TESTER is not set
# CONFIG_DEBUG_SPINLOCK is not set
# CONFIG_DEBUG_MUTEXES is not set
# CONFIG_DEBUG_SPINLOCK_SLEEP is not set
# CONFIG_DEBUG_LOCKING_API_SELFTESTS is not set
# CONFIG_DEBUG_KOBJECT is not set
CONFIG_DEBUG_BUGVERBOSE=y
# CONFIG_DEBUG_INFO is not set
# CONFIG_DEBUG_VM is not set
# CONFIG_DEBUG_LIST is not set
# CONFIG_DEBUG_SG is not set
# CONFIG_BOOT_PRINTK_DELAY is not set
# CONFIG_RCU_TORTURE_TEST is not set
# CONFIG_BACKTRACE_SELF_TEST is not set
# CONFIG_FAULT_INJECTION is not set
# CONFIG_SAMPLES is not set
# CONFIG_DEBUG_RODATA is not set

#
# Security options
#
# CONFIG_KEYS is not set
CONFIG_SECURITY=y
CONFIG_SECURITY_NETWORK=y
CONFIG_SECURITY_CAPABILITIES=y
# CONFIG_SECURITY_FILE_CAPABILITIES is not set
CONFIG_SECURITY_DEFAULT_MMAP_MIN_ADDR=0
CONFIG_CRYPTO=y
CONFIG_CRYPTO_ALGAPI=y
CONFIG_CRYPTO_BLKCIPHER=y
# CONFIG_CRYPTO_SEQIV is not set
CONFIG_CRYPTO_MANAGER=y
# CONFIG_CRYPTO_HMAC is not set
# CONFIG_CRYPTO_XCBC is not set
# CONFIG_CRYPTO_NULL is not set
# CONFIG_CRYPTO_MD4 is not set
# CONFIG_CRYPTO_MD5 is not set
# CONFIG_CRYPTO_SHA1 is not set
# CONFIG_CRYPTO_SHA256 is not set
# CONFIG_CRYPTO_SHA512 is not set
# CONFIG_CRYPTO_WP512 is not set
# CONFIG_CRYPTO_TGR192 is not set
# CONFIG_CRYPTO_GF128MUL is not set
CONFIG_CRYPTO_ECB=m
CONFIG_CRYPTO_CBC=y
# CONFIG_CRYPTO_PCBC is not set
# CONFIG_CRYPTO_LRW is not set
# CONFIG_CRYPTO_XTS is not set
# CONFIG_CRYPTO_CTR is not set
# CONFIG_CRYPTO_GCM is not set
# CONFIG_CRYPTO_CCM is not set
# CONFIG_CRYPTO_CRYPTD is not set
# CONFIG_CRYPTO_DES is not set
# CONFIG_CRYPTO_FCRYPT is not set
# CONFIG_CRYPTO_BLOWFISH is not set
# CONFIG_CRYPTO_TWOFISH is not set
# CONFIG_CRYPTO_SERPENT is not set
CONFIG_CRYPTO_AES=m
# CONFIG_CRYPTO_CAST5 is not set
# CONFIG_CRYPTO_CAST6 is not set
# CONFIG_CRYPTO_TEA is not set
CONFIG_CRYPTO_ARC4=m
# CONFIG_CRYPTO_KHAZAD is not set
# CONFIG_CRYPTO_ANUBIS is not set
# CONFIG_CRYPTO_SEED is not set
# CONFIG_CRYPTO_SALSA20 is not set
# CONFIG_CRYPTO_DEFLATE is not set
CONFIG_CRYPTO_MICHAEL_MIC=m
# CONFIG_CRYPTO_CRC32C is not set
# CONFIG_CRYPTO_CAMELLIA is not set
# CONFIG_CRYPTO_TEST is not set
# CONFIG_CRYPTO_AUTHENC is not set
# CONFIG_CRYPTO_LZO is not set
# CONFIG_CRYPTO_HW is not set

#
# Library routines
#
CONFIG_BITREVERSE=y
# CONFIG_CRC_CCITT is not set
# CONFIG_CRC16 is not set
# CONFIG_CRC_ITU_T is not set
CONFIG_CRC32=y
# CONFIG_CRC7 is not set
# CONFIG_LIBCRC32C is not set
CONFIG_ZLIB_INFLATE=m
CONFIG_PLIST=y
CONFIG_HAS_IOMEM=y
CONFIG_HAS_IOPORT=y
CONFIG_HAS_DMA=y

-----[ Domenico Andreoli, aka cavok
 --[ http://www.dandreoli.com/gpgkey.asc
   ---[ 3A0F 2F80 F79C 678A 8936  4FEE 0677 9033 A20E BC50

Re: [git pull] kgdb-light -v10

[Jason Wessel]

Domenico Andreoli wrote:
> Hi,
>
> On Tue, Feb 12, 2008 at 12:27:47PM +0100, Ingo Molnar wrote:
>   
>> this is kgdb-light, version -v10 (against Linus-latest), and can be 
>> pulled from:
>>
>>    git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-kgdb.git
>>
>> shortlog, diffstat and full patch can be found further below.
>>     
>
>   I am just trying to play with this, I am not able to make it work.
> Assume I am able with git, I use it every day on my software, then I
> am correctly tracking and building your branch on git.kernel.org.
>
> My config has both KGDB and KGDB_SERIAL_CONSOLE. kernel command line
> has kgdbwait kgdboc=ttyS0,115200. linux console is not on serial but if
> do not enable KGDB_SERIAL_CONSOLE I am then unable to hit SysRq+g. If
> instead I use linux serial console, gdb messes with getty and things
> quickly get worse.
>
> 1. at boot, kernel waits for a gdb connection
> 2. gdb connection is established from another box
> 3. gdb breaks in
> 4. hit continue at gdb prompt
> 5. target box returns to life. everything looks ok (it is 2.6.25-rc1!)
> 6. SysRq+h on the target correctly shows the help on the console
> 7. SysRq+g on the target, it prints "SysRq : GDB" and hangs forever
> 8. gdb on the host does not break in
>
> is really that simple, am i overlooking anything? thank you.
>
> regards,
> Domenico
>
>   
I doubt the .config you posted was the one you used, because there were
no KGDB options specified at all.

If you want to be using your vga device as the console that is ok. You
can still activate the sysrq with running the command: echo g >
/proc/sysrq-trigger

You might consider doing "set debug remote 1" in the gdb session if you
want to see what is going on. After the continue, the next time you
break in with the debugger it should send $T.........etc which is a stop
packet.

Jason.

Re: [git pull] kgdb-light -v10

[Domenico Andreoli]

On Tue, Feb 12, 2008 at 07:59:02AM -0600, Jason Wessel wrote:
>
> I doubt the .config you posted was the one you used, because there were
> no KGDB options specified at all.

indeed it was of a parisc.. :)

here is the right one:

#
# Automatically generated make config: don't edit
# Linux kernel version: 2.6.25-rc1
# Tue Feb 12 13:11:26 2008
#
# CONFIG_64BIT is not set
CONFIG_X86_32=y
# CONFIG_X86_64 is not set
CONFIG_X86=y
# CONFIG_GENERIC_LOCKBREAK is not set
CONFIG_GENERIC_TIME=y
CONFIG_GENERIC_CMOS_UPDATE=y
CONFIG_CLOCKSOURCE_WATCHDOG=y
CONFIG_GENERIC_CLOCKEVENTS=y
CONFIG_GENERIC_CLOCKEVENTS_BROADCAST=y
CONFIG_LOCKDEP_SUPPORT=y
CONFIG_STACKTRACE_SUPPORT=y
CONFIG_HAVE_LATENCYTOP_SUPPORT=y
CONFIG_SEMAPHORE_SLEEPERS=y
CONFIG_FAST_CMPXCHG_LOCAL=y
CONFIG_MMU=y
CONFIG_ZONE_DMA=y
CONFIG_QUICKLIST=y
CONFIG_GENERIC_ISA_DMA=y
CONFIG_GENERIC_IOMAP=y
CONFIG_GENERIC_BUG=y
CONFIG_GENERIC_HWEIGHT=y
# CONFIG_GENERIC_GPIO is not set
CONFIG_ARCH_MAY_HAVE_PC_FDC=y
CONFIG_DMI=y
# CONFIG_RWSEM_GENERIC_SPINLOCK is not set
CONFIG_RWSEM_XCHGADD_ALGORITHM=y
# CONFIG_ARCH_HAS_ILOG2_U32 is not set
# CONFIG_ARCH_HAS_ILOG2_U64 is not set
CONFIG_ARCH_HAS_CPU_IDLE_WAIT=y
CONFIG_GENERIC_CALIBRATE_DELAY=y
# CONFIG_GENERIC_TIME_VSYSCALL is not set
CONFIG_ARCH_HAS_CPU_RELAX=y
# CONFIG_HAVE_SETUP_PER_CPU_AREA is not set
CONFIG_ARCH_HIBERNATION_POSSIBLE=y
CONFIG_ARCH_SUSPEND_POSSIBLE=y
# CONFIG_ZONE_DMA32 is not set
CONFIG_ARCH_POPULATES_NODE_MAP=y
# CONFIG_AUDIT_ARCH is not set
CONFIG_ARCH_SUPPORTS_AOUT=y
CONFIG_GENERIC_HARDIRQS=y
CONFIG_GENERIC_IRQ_PROBE=y
CONFIG_X86_BIOS_REBOOT=y
CONFIG_KTIME_SCALAR=y
CONFIG_DEFCONFIG_LIST="/lib/modules/$UNAME_RELEASE/.config"

#
# General setup
#
CONFIG_EXPERIMENTAL=y
CONFIG_BROKEN_ON_SMP=y
CONFIG_LOCK_KERNEL=y
CONFIG_INIT_ENV_ARG_LIMIT=32
CONFIG_LOCALVERSION=""
CONFIG_LOCALVERSION_AUTO=y
CONFIG_SWAP=y
CONFIG_SYSVIPC=y
CONFIG_SYSVIPC_SYSCTL=y
# CONFIG_POSIX_MQUEUE is not set
# CONFIG_BSD_PROCESS_ACCT is not set
# CONFIG_TASKSTATS is not set
# CONFIG_AUDIT is not set
CONFIG_IKCONFIG=y
# CONFIG_IKCONFIG_PROC is not set
CONFIG_LOG_BUF_SHIFT=14
# CONFIG_CGROUPS is not set
# CONFIG_FAIR_GROUP_SCHED is not set
# CONFIG_SYSFS_DEPRECATED is not set
# CONFIG_RELAY is not set
CONFIG_NAMESPACES=y
# CONFIG_UTS_NS is not set
# CONFIG_IPC_NS is not set
# CONFIG_USER_NS is not set
# CONFIG_PID_NS is not set
# CONFIG_BLK_DEV_INITRD is not set
# CONFIG_CC_OPTIMIZE_FOR_SIZE is not set
CONFIG_SYSCTL=y
# CONFIG_EMBEDDED is not set
CONFIG_UID16=y
CONFIG_SYSCTL_SYSCALL=y
CONFIG_KALLSYMS=y
CONFIG_KALLSYMS_ALL=y
# CONFIG_KALLSYMS_EXTRA_PASS is not set
CONFIG_HOTPLUG=y
CONFIG_PRINTK=y
CONFIG_BUG=y
CONFIG_ELF_CORE=y
# CONFIG_COMPAT_BRK is not set
CONFIG_BASE_FULL=y
CONFIG_FUTEX=y
CONFIG_ANON_INODES=y
CONFIG_EPOLL=y
CONFIG_SIGNALFD=y
CONFIG_TIMERFD=y
CONFIG_EVENTFD=y
CONFIG_SHMEM=y
CONFIG_VM_EVENT_COUNTERS=y
CONFIG_SLUB_DEBUG=y
# CONFIG_SLAB is not set
CONFIG_SLUB=y
# CONFIG_SLOB is not set
# CONFIG_PROFILING is not set
# CONFIG_MARKERS is not set
CONFIG_HAVE_OPROFILE=y
# CONFIG_KPROBES is not set
CONFIG_HAVE_KPROBES=y
CONFIG_PROC_PAGE_MONITOR=y
CONFIG_SLABINFO=y
CONFIG_RT_MUTEXES=y
# CONFIG_TINY_SHMEM is not set
CONFIG_BASE_SMALL=0
CONFIG_MODULES=y
CONFIG_MODULE_UNLOAD=y
# CONFIG_MODULE_FORCE_UNLOAD is not set
# CONFIG_MODVERSIONS is not set
CONFIG_MODULE_SRCVERSION_ALL=y
CONFIG_KMOD=y
CONFIG_BLOCK=y
# CONFIG_LBD is not set
# CONFIG_BLK_DEV_IO_TRACE is not set
# CONFIG_LSF is not set
# CONFIG_BLK_DEV_BSG is not set

#
# IO Schedulers
#
CONFIG_IOSCHED_NOOP=y
# CONFIG_IOSCHED_AS is not set
# CONFIG_IOSCHED_DEADLINE is not set
CONFIG_IOSCHED_CFQ=y
# CONFIG_DEFAULT_AS is not set
# CONFIG_DEFAULT_DEADLINE is not set
CONFIG_DEFAULT_CFQ=y
# CONFIG_DEFAULT_NOOP is not set
CONFIG_DEFAULT_IOSCHED="cfq"
CONFIG_CLASSIC_RCU=y
# CONFIG_PREEMPT_RCU is not set

#
# Processor type and features
#
CONFIG_TICK_ONESHOT=y
CONFIG_NO_HZ=y
CONFIG_HIGH_RES_TIMERS=y
CONFIG_GENERIC_CLOCKEVENTS_BUILD=y
# CONFIG_SMP is not set
CONFIG_X86_PC=y
# CONFIG_X86_ELAN is not set
# CONFIG_X86_VOYAGER is not set
# CONFIG_X86_NUMAQ is not set
# CONFIG_X86_SUMMIT is not set
# CONFIG_X86_BIGSMP is not set
# CONFIG_X86_VISWS is not set
# CONFIG_X86_GENERICARCH is not set
# CONFIG_X86_ES7000 is not set
# CONFIG_X86_RDC321X is not set
# CONFIG_X86_VSMP is not set
# CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER is not set
# CONFIG_PARAVIRT_GUEST is not set
# CONFIG_M386 is not set
# CONFIG_M486 is not set
# CONFIG_M586 is not set
# CONFIG_M586TSC is not set
# CONFIG_M586MMX is not set
# CONFIG_M686 is not set
# CONFIG_MPENTIUMII is not set
# CONFIG_MPENTIUMIII is not set
CONFIG_MPENTIUMM=y
# CONFIG_MPENTIUM4 is not set
# CONFIG_MK6 is not set
# CONFIG_MK7 is not set
# CONFIG_MK8 is not set
# CONFIG_MCRUSOE is not set
# CONFIG_MEFFICEON is not set
# CONFIG_MWINCHIPC6 is not set
# CONFIG_MWINCHIP2 is not set
# CONFIG_MWINCHIP3D is not set
# CONFIG_MGEODEGX1 is not set
# CONFIG_MGEODE_LX is not set
# CONFIG_MCYRIXIII is not set
# CONFIG_MVIAC3_2 is not set
# CONFIG_MVIAC7 is not set
# CONFIG_MPSC is not set
# CONFIG_MCORE2 is not set
# CONFIG_GENERIC_CPU is not set
# CONFIG_X86_GENERIC is not set
CONFIG_X86_CMPXCHG=y
CONFIG_X86_L1_CACHE_SHIFT=6
CONFIG_X86_XADD=y
CONFIG_X86_WP_WORKS_OK=y
CONFIG_X86_INVLPG=y
CONFIG_X86_BSWAP=y
CONFIG_X86_POPAD_OK=y
CONFIG_X86_GOOD_APIC=y
CONFIG_X86_INTEL_USERCOPY=y
CONFIG_X86_USE_PPRO_CHECKSUM=y
CONFIG_X86_TSC=y
CONFIG_X86_CMOV=y
CONFIG_X86_MINIMUM_CPU_FAMILY=4
CONFIG_X86_DEBUGCTLMSR=y
# CONFIG_HPET_TIMER is not set
# CONFIG_IOMMU_HELPER is not set
# CONFIG_PREEMPT_NONE is not set
# CONFIG_PREEMPT_VOLUNTARY is not set
CONFIG_PREEMPT=y
# CONFIG_RCU_TRACE is not set
CONFIG_X86_UP_APIC=y
CONFIG_X86_UP_IOAPIC=y
CONFIG_X86_LOCAL_APIC=y
CONFIG_X86_IO_APIC=y
CONFIG_X86_MCE=y
# CONFIG_X86_MCE_NONFATAL is not set
# CONFIG_X86_MCE_P4THERMAL is not set
CONFIG_VM86=y
# CONFIG_TOSHIBA is not set
# CONFIG_I8K is not set
# CONFIG_X86_REBOOTFIXUPS is not set
# CONFIG_MICROCODE is not set
# CONFIG_X86_MSR is not set
# CONFIG_X86_CPUID is not set
# CONFIG_NOHIGHMEM is not set
CONFIG_HIGHMEM4G=y
# CONFIG_HIGHMEM64G is not set
CONFIG_PAGE_OFFSET=0xC0000000
CONFIG_HIGHMEM=y
CONFIG_ARCH_FLATMEM_ENABLE=y
CONFIG_ARCH_SPARSEMEM_ENABLE=y
CONFIG_ARCH_SELECT_MEMORY_MODEL=y
CONFIG_SELECT_MEMORY_MODEL=y
CONFIG_FLATMEM_MANUAL=y
# CONFIG_DISCONTIGMEM_MANUAL is not set
# CONFIG_SPARSEMEM_MANUAL is not set
CONFIG_FLATMEM=y
CONFIG_FLAT_NODE_MEM_MAP=y
CONFIG_SPARSEMEM_STATIC=y
# CONFIG_SPARSEMEM_VMEMMAP_ENABLE is not set
CONFIG_SPLIT_PTLOCK_CPUS=4
# CONFIG_RESOURCES_64BIT is not set
CONFIG_ZONE_DMA_FLAG=1
CONFIG_BOUNCE=y
CONFIG_NR_QUICK=1
CONFIG_VIRT_TO_BUS=y
# CONFIG_HIGHPTE is not set
# CONFIG_MATH_EMULATION is not set
# CONFIG_MTRR is not set
# CONFIG_EFI is not set
# CONFIG_SECCOMP is not set
# CONFIG_HZ_100 is not set
CONFIG_HZ_250=y
# CONFIG_HZ_300 is not set
# CONFIG_HZ_1000 is not set
CONFIG_HZ=250
CONFIG_SCHED_HRTICK=y
# CONFIG_KEXEC is not set
# CONFIG_CRASH_DUMP is not set
CONFIG_PHYSICAL_START=0x100000
# CONFIG_RELOCATABLE is not set
CONFIG_PHYSICAL_ALIGN=0x100000
CONFIG_COMPAT_VDSO=y
CONFIG_ARCH_ENABLE_MEMORY_HOTPLUG=y

#
# Power management options
#
CONFIG_PM=y
# CONFIG_PM_LEGACY is not set
# CONFIG_PM_DEBUG is not set
CONFIG_PM_SLEEP=y
CONFIG_SUSPEND=y
CONFIG_SUSPEND_FREEZER=y
CONFIG_HIBERNATION=y
CONFIG_PM_STD_PARTITION=""
CONFIG_ACPI=y
CONFIG_ACPI_SLEEP=y
# CONFIG_ACPI_PROCFS is not set
# CONFIG_ACPI_PROCFS_POWER is not set
CONFIG_ACPI_SYSFS_POWER=y
CONFIG_ACPI_PROC_EVENT=y
CONFIG_ACPI_AC=y
CONFIG_ACPI_BATTERY=y
CONFIG_ACPI_BUTTON=y
CONFIG_ACPI_FAN=y
CONFIG_ACPI_DOCK=y
# CONFIG_ACPI_BAY is not set
CONFIG_ACPI_PROCESSOR=y
CONFIG_ACPI_THERMAL=y
# CONFIG_ACPI_WMI is not set
# CONFIG_ACPI_ASUS is not set
# CONFIG_ACPI_TOSHIBA is not set
CONFIG_ACPI_BLACKLIST_YEAR=0
# CONFIG_ACPI_DEBUG is not set
CONFIG_ACPI_EC=y
CONFIG_ACPI_POWER=y
CONFIG_ACPI_SYSTEM=y
CONFIG_X86_PM_TIMER=y
# CONFIG_ACPI_CONTAINER is not set
# CONFIG_ACPI_SBS is not set
# CONFIG_APM is not set

#
# CPU Frequency scaling
#
CONFIG_CPU_FREQ=y
CONFIG_CPU_FREQ_TABLE=y
# CONFIG_CPU_FREQ_DEBUG is not set
CONFIG_CPU_FREQ_STAT=y
# CONFIG_CPU_FREQ_STAT_DETAILS is not set
# CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE is not set
# CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE is not set
CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND=y
# CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE is not set
CONFIG_CPU_FREQ_GOV_PERFORMANCE=y
# CONFIG_CPU_FREQ_GOV_POWERSAVE is not set
# CONFIG_CPU_FREQ_GOV_USERSPACE is not set
CONFIG_CPU_FREQ_GOV_ONDEMAND=y
# CONFIG_CPU_FREQ_GOV_CONSERVATIVE is not set

#
# CPUFreq processor drivers
#
CONFIG_X86_ACPI_CPUFREQ=m
# CONFIG_X86_POWERNOW_K6 is not set
# CONFIG_X86_POWERNOW_K7 is not set
# CONFIG_X86_POWERNOW_K8 is not set
# CONFIG_X86_GX_SUSPMOD is not set
CONFIG_X86_SPEEDSTEP_CENTRINO=m
CONFIG_X86_SPEEDSTEP_CENTRINO_TABLE=y
# CONFIG_X86_SPEEDSTEP_ICH is not set
# CONFIG_X86_SPEEDSTEP_SMI is not set
# CONFIG_X86_P4_CLOCKMOD is not set
# CONFIG_X86_CPUFREQ_NFORCE2 is not set
# CONFIG_X86_LONGRUN is not set
# CONFIG_X86_LONGHAUL is not set
# CONFIG_X86_E_POWERSAVER is not set

#
# shared options
#
# CONFIG_X86_ACPI_CPUFREQ_PROC_INTF is not set
# CONFIG_X86_SPEEDSTEP_LIB is not set
# CONFIG_CPU_IDLE is not set

#
# Bus options (PCI etc.)
#
CONFIG_PCI=y
# CONFIG_PCI_GOBIOS is not set
# CONFIG_PCI_GOMMCONFIG is not set
# CONFIG_PCI_GODIRECT is not set
CONFIG_PCI_GOANY=y
CONFIG_PCI_BIOS=y
CONFIG_PCI_DIRECT=y
CONFIG_PCI_MMCONFIG=y
CONFIG_PCI_DOMAINS=y
CONFIG_PCIEPORTBUS=y
CONFIG_PCIEAER=y
CONFIG_ARCH_SUPPORTS_MSI=y
# CONFIG_PCI_MSI is not set
CONFIG_PCI_LEGACY=y
# CONFIG_PCI_DEBUG is not set
CONFIG_HT_IRQ=y
CONFIG_ISA_DMA_API=y
# CONFIG_ISA is not set
# CONFIG_MCA is not set
# CONFIG_SCx200 is not set
CONFIG_PCCARD=m
# CONFIG_PCMCIA_DEBUG is not set
CONFIG_PCMCIA=m
CONFIG_PCMCIA_LOAD_CIS=y
CONFIG_PCMCIA_IOCTL=y
CONFIG_CARDBUS=y

#
# PC-card bridges
#
CONFIG_YENTA=m
CONFIG_YENTA_O2=y
CONFIG_YENTA_RICOH=y
CONFIG_YENTA_TI=y
CONFIG_YENTA_ENE_TUNE=y
CONFIG_YENTA_TOSHIBA=y
# CONFIG_PD6729 is not set
# CONFIG_I82092 is not set
CONFIG_PCCARD_NONSTATIC=m
# CONFIG_HOTPLUG_PCI is not set

#
# Executable file formats / Emulations
#
CONFIG_BINFMT_ELF=y
# CONFIG_BINFMT_AOUT is not set
CONFIG_BINFMT_MISC=m

#
# Networking
#
CONFIG_NET=y

#
# Networking options
#
CONFIG_PACKET=y
CONFIG_PACKET_MMAP=y
CONFIG_UNIX=y
# CONFIG_NET_KEY is not set
CONFIG_INET=y
# CONFIG_IP_MULTICAST is not set
# CONFIG_IP_ADVANCED_ROUTER is not set
CONFIG_IP_FIB_HASH=y
# CONFIG_IP_PNP is not set
# CONFIG_NET_IPIP is not set
# CONFIG_NET_IPGRE is not set
# CONFIG_ARPD is not set
# CONFIG_SYN_COOKIES is not set
# CONFIG_INET_AH is not set
# CONFIG_INET_ESP is not set
# CONFIG_INET_IPCOMP is not set
# CONFIG_INET_XFRM_TUNNEL is not set
# CONFIG_INET_TUNNEL is not set
# CONFIG_INET_XFRM_MODE_TRANSPORT is not set
# CONFIG_INET_XFRM_MODE_TUNNEL is not set
# CONFIG_INET_XFRM_MODE_BEET is not set
# CONFIG_INET_LRO is not set
CONFIG_INET_DIAG=y
CONFIG_INET_TCP_DIAG=y
# CONFIG_TCP_CONG_ADVANCED is not set
CONFIG_TCP_CONG_CUBIC=y
CONFIG_DEFAULT_TCP_CONG="cubic"
# CONFIG_TCP_MD5SIG is not set
# CONFIG_IP_VS is not set
# CONFIG_IPV6 is not set
# CONFIG_INET6_XFRM_TUNNEL is not set
# CONFIG_INET6_TUNNEL is not set
# CONFIG_NETLABEL is not set
# CONFIG_NETWORK_SECMARK is not set
CONFIG_NETFILTER=y
# CONFIG_NETFILTER_DEBUG is not set
CONFIG_NETFILTER_ADVANCED=y

#
# Core Netfilter Configuration
#
# CONFIG_NETFILTER_NETLINK_QUEUE is not set
# CONFIG_NETFILTER_NETLINK_LOG is not set
CONFIG_NF_CONNTRACK=m
# CONFIG_NF_CT_ACCT is not set
# CONFIG_NF_CONNTRACK_MARK is not set
# CONFIG_NF_CONNTRACK_EVENTS is not set
# CONFIG_NF_CT_PROTO_SCTP is not set
# CONFIG_NF_CT_PROTO_UDPLITE is not set
# CONFIG_NF_CONNTRACK_AMANDA is not set
# CONFIG_NF_CONNTRACK_FTP is not set
# CONFIG_NF_CONNTRACK_H323 is not set
# CONFIG_NF_CONNTRACK_IRC is not set
# CONFIG_NF_CONNTRACK_NETBIOS_NS is not set
# CONFIG_NF_CONNTRACK_PPTP is not set
# CONFIG_NF_CONNTRACK_SANE is not set
# CONFIG_NF_CONNTRACK_SIP is not set
# CONFIG_NF_CONNTRACK_TFTP is not set
# CONFIG_NF_CT_NETLINK is not set
CONFIG_NETFILTER_XTABLES=m
# CONFIG_NETFILTER_XT_TARGET_CLASSIFY is not set
# CONFIG_NETFILTER_XT_TARGET_MARK is not set
# CONFIG_NETFILTER_XT_TARGET_NFQUEUE is not set
# CONFIG_NETFILTER_XT_TARGET_NFLOG is not set
# CONFIG_NETFILTER_XT_TARGET_RATEEST is not set
# CONFIG_NETFILTER_XT_TARGET_TCPMSS is not set
# CONFIG_NETFILTER_XT_MATCH_COMMENT is not set
# CONFIG_NETFILTER_XT_MATCH_CONNBYTES is not set
# CONFIG_NETFILTER_XT_MATCH_CONNLIMIT is not set
# CONFIG_NETFILTER_XT_MATCH_CONNMARK is not set
# CONFIG_NETFILTER_XT_MATCH_CONNTRACK is not set
# CONFIG_NETFILTER_XT_MATCH_DCCP is not set
# CONFIG_NETFILTER_XT_MATCH_DSCP is not set
# CONFIG_NETFILTER_XT_MATCH_ESP is not set
# CONFIG_NETFILTER_XT_MATCH_HELPER is not set
# CONFIG_NETFILTER_XT_MATCH_IPRANGE is not set
# CONFIG_NETFILTER_XT_MATCH_LENGTH is not set
# CONFIG_NETFILTER_XT_MATCH_LIMIT is not set
# CONFIG_NETFILTER_XT_MATCH_MAC is not set
# CONFIG_NETFILTER_XT_MATCH_MARK is not set
# CONFIG_NETFILTER_XT_MATCH_OWNER is not set
# CONFIG_NETFILTER_XT_MATCH_MULTIPORT is not set
# CONFIG_NETFILTER_XT_MATCH_PKTTYPE is not set
# CONFIG_NETFILTER_XT_MATCH_QUOTA is not set
# CONFIG_NETFILTER_XT_MATCH_RATEEST is not set
# CONFIG_NETFILTER_XT_MATCH_REALM is not set
# CONFIG_NETFILTER_XT_MATCH_SCTP is not set
# CONFIG_NETFILTER_XT_MATCH_STATE is not set
# CONFIG_NETFILTER_XT_MATCH_STATISTIC is not set
# CONFIG_NETFILTER_XT_MATCH_STRING is not set
# CONFIG_NETFILTER_XT_MATCH_TCPMSS is not set
# CONFIG_NETFILTER_XT_MATCH_TIME is not set
# CONFIG_NETFILTER_XT_MATCH_U32 is not set
# CONFIG_NETFILTER_XT_MATCH_HASHLIMIT is not set

#
# IP: Netfilter Configuration
#
CONFIG_NF_CONNTRACK_IPV4=m
CONFIG_NF_CONNTRACK_PROC_COMPAT=y
# CONFIG_IP_NF_QUEUE is not set
CONFIG_IP_NF_IPTABLES=m
# CONFIG_IP_NF_MATCH_RECENT is not set
# CONFIG_IP_NF_MATCH_ECN is not set
# CONFIG_IP_NF_MATCH_AH is not set
# CONFIG_IP_NF_MATCH_TTL is not set
# CONFIG_IP_NF_MATCH_ADDRTYPE is not set
# CONFIG_IP_NF_FILTER is not set
# CONFIG_IP_NF_TARGET_LOG is not set
# CONFIG_IP_NF_TARGET_ULOG is not set
# CONFIG_NF_NAT is not set
# CONFIG_IP_NF_MANGLE is not set
# CONFIG_IP_NF_RAW is not set
# CONFIG_IP_NF_ARPTABLES is not set
# CONFIG_IP_DCCP is not set
# CONFIG_IP_SCTP is not set
# CONFIG_TIPC is not set
# CONFIG_ATM is not set
# CONFIG_BRIDGE is not set
# CONFIG_VLAN_8021Q is not set
# CONFIG_DECNET is not set
# CONFIG_LLC2 is not set
# CONFIG_IPX is not set
# CONFIG_ATALK is not set
# CONFIG_X25 is not set
# CONFIG_LAPB is not set
# CONFIG_ECONET is not set
# CONFIG_WAN_ROUTER is not set
# CONFIG_NET_SCHED is not set
CONFIG_NET_SCH_FIFO=y

#
# Network testing
#
# CONFIG_NET_PKTGEN is not set
# CONFIG_HAMRADIO is not set
# CONFIG_CAN is not set
# CONFIG_IRDA is not set
# CONFIG_BT is not set
# CONFIG_AF_RXRPC is not set

#
# Wireless
#
CONFIG_CFG80211=m
# CONFIG_NL80211 is not set
CONFIG_WIRELESS_EXT=y
CONFIG_MAC80211=m

#
# Rate control algorithm selection
#
CONFIG_MAC80211_RC_DEFAULT_PID=y
# CONFIG_MAC80211_RC_DEFAULT_SIMPLE is not set
# CONFIG_MAC80211_RC_DEFAULT_NONE is not set

#
# Selecting 'y' for an algorithm will
#

#
# build the algorithm into mac80211.
#
CONFIG_MAC80211_RC_DEFAULT="pid"
CONFIG_MAC80211_RC_PID=y
# CONFIG_MAC80211_RC_SIMPLE is not set
# CONFIG_MAC80211_DEBUG_PACKET_ALIGNMENT is not set
# CONFIG_MAC80211_DEBUG is not set
CONFIG_IEEE80211=m
# CONFIG_IEEE80211_DEBUG is not set
# CONFIG_IEEE80211_CRYPT_WEP is not set
# CONFIG_IEEE80211_CRYPT_CCMP is not set
# CONFIG_IEEE80211_CRYPT_TKIP is not set
# CONFIG_IEEE80211_SOFTMAC is not set
# CONFIG_RFKILL is not set
# CONFIG_NET_9P is not set

#
# Device Drivers
#

#
# Generic Driver Options
#
CONFIG_UEVENT_HELPER_PATH="/sbin/hotplug"
CONFIG_STANDALONE=y
# CONFIG_PREVENT_FIRMWARE_BUILD is not set
CONFIG_FW_LOADER=m
# CONFIG_DEBUG_DRIVER is not set
# CONFIG_DEBUG_DEVRES is not set
# CONFIG_SYS_HYPERVISOR is not set
# CONFIG_CONNECTOR is not set
# CONFIG_MTD is not set
# CONFIG_PARPORT is not set
CONFIG_PNP=y
# CONFIG_PNP_DEBUG is not set

#
# Protocols
#
CONFIG_PNPACPI=y
CONFIG_BLK_DEV=y
# CONFIG_BLK_DEV_FD is not set
# CONFIG_BLK_CPQ_DA is not set
# CONFIG_BLK_CPQ_CISS_DA is not set
# CONFIG_BLK_DEV_DAC960 is not set
# CONFIG_BLK_DEV_UMEM is not set
# CONFIG_BLK_DEV_COW_COMMON is not set
CONFIG_BLK_DEV_LOOP=y
CONFIG_BLK_DEV_CRYPTOLOOP=y
# CONFIG_BLK_DEV_NBD is not set
# CONFIG_BLK_DEV_SX8 is not set
# CONFIG_BLK_DEV_UB is not set
CONFIG_BLK_DEV_RAM=y
CONFIG_BLK_DEV_RAM_COUNT=16
CONFIG_BLK_DEV_RAM_SIZE=4096
# CONFIG_BLK_DEV_XIP is not set
# CONFIG_CDROM_PKTCDVD is not set
# CONFIG_ATA_OVER_ETH is not set
# CONFIG_MISC_DEVICES is not set
CONFIG_HAVE_IDE=y
CONFIG_IDE=y
CONFIG_BLK_DEV_IDE=y

#
# Please see Documentation/ide.txt for help/info on IDE drives
#
# CONFIG_BLK_DEV_IDE_SATA is not set
# CONFIG_BLK_DEV_HD_IDE is not set
# CONFIG_BLK_DEV_IDEDISK is not set
CONFIG_IDEDISK_MULTI_MODE=y
# CONFIG_BLK_DEV_IDECS is not set
# CONFIG_BLK_DEV_DELKIN is not set
# CONFIG_BLK_DEV_IDECD is not set
# CONFIG_BLK_DEV_IDETAPE is not set
# CONFIG_BLK_DEV_IDEFLOPPY is not set
# CONFIG_BLK_DEV_IDESCSI is not set
# CONFIG_BLK_DEV_IDEACPI is not set
# CONFIG_IDE_TASK_IOCTL is not set
CONFIG_IDE_PROC_FS=y

#
# IDE chipset support/bugfixes
#
# CONFIG_IDE_GENERIC is not set
# CONFIG_BLK_DEV_PLATFORM is not set
# CONFIG_BLK_DEV_CMD640 is not set
# CONFIG_BLK_DEV_IDEPNP is not set
CONFIG_BLK_DEV_IDEDMA_SFF=y

#
# PCI IDE chipsets support
#
CONFIG_BLK_DEV_IDEPCI=y
CONFIG_IDEPCI_PCIBUS_ORDER=y
# CONFIG_BLK_DEV_OFFBOARD is not set
CONFIG_BLK_DEV_GENERIC=y
# CONFIG_BLK_DEV_OPTI621 is not set
# CONFIG_BLK_DEV_RZ1000 is not set
CONFIG_BLK_DEV_IDEDMA_PCI=y
# CONFIG_BLK_DEV_AEC62XX is not set
# CONFIG_BLK_DEV_ALI15X3 is not set
# CONFIG_BLK_DEV_AMD74XX is not set
# CONFIG_BLK_DEV_ATIIXP is not set
# CONFIG_BLK_DEV_CMD64X is not set
# CONFIG_BLK_DEV_TRIFLEX is not set
# CONFIG_BLK_DEV_CY82C693 is not set
# CONFIG_BLK_DEV_CS5520 is not set
# CONFIG_BLK_DEV_CS5530 is not set
# CONFIG_BLK_DEV_CS5535 is not set
# CONFIG_BLK_DEV_HPT34X is not set
# CONFIG_BLK_DEV_HPT366 is not set
# CONFIG_BLK_DEV_JMICRON is not set
# CONFIG_BLK_DEV_SC1200 is not set
CONFIG_BLK_DEV_PIIX=y
# CONFIG_BLK_DEV_IT8213 is not set
# CONFIG_BLK_DEV_IT821X is not set
# CONFIG_BLK_DEV_NS87415 is not set
# CONFIG_BLK_DEV_PDC202XX_OLD is not set
# CONFIG_BLK_DEV_PDC202XX_NEW is not set
# CONFIG_BLK_DEV_SVWKS is not set
# CONFIG_BLK_DEV_SIIMAGE is not set
# CONFIG_BLK_DEV_SIS5513 is not set
# CONFIG_BLK_DEV_SLC90E66 is not set
# CONFIG_BLK_DEV_TRM290 is not set
# CONFIG_BLK_DEV_VIA82CXXX is not set
# CONFIG_BLK_DEV_TC86C001 is not set
CONFIG_BLK_DEV_IDEDMA=y
CONFIG_IDE_ARCH_OBSOLETE_INIT=y
# CONFIG_BLK_DEV_HD is not set

#
# SCSI device support
#
CONFIG_RAID_ATTRS=y
CONFIG_SCSI=y
CONFIG_SCSI_DMA=y
CONFIG_SCSI_TGT=y
# CONFIG_SCSI_NETLINK is not set
CONFIG_SCSI_PROC_FS=y

#
# SCSI support type (disk, tape, CD-ROM)
#
CONFIG_BLK_DEV_SD=y
# CONFIG_CHR_DEV_ST is not set
# CONFIG_CHR_DEV_OSST is not set
CONFIG_BLK_DEV_SR=m
# CONFIG_BLK_DEV_SR_VENDOR is not set
# CONFIG_CHR_DEV_SG is not set
# CONFIG_CHR_DEV_SCH is not set

#
# Some SCSI devices (e.g. CD jukebox) support multiple LUNs
#
CONFIG_SCSI_MULTI_LUN=y
# CONFIG_SCSI_CONSTANTS is not set
# CONFIG_SCSI_LOGGING is not set
# CONFIG_SCSI_SCAN_ASYNC is not set
CONFIG_SCSI_WAIT_SCAN=m

#
# SCSI Transports
#
# CONFIG_SCSI_SPI_ATTRS is not set
# CONFIG_SCSI_FC_ATTRS is not set
# CONFIG_SCSI_ISCSI_ATTRS is not set
# CONFIG_SCSI_SAS_LIBSAS is not set
# CONFIG_SCSI_SRP_ATTRS is not set
CONFIG_SCSI_LOWLEVEL=y
# CONFIG_ISCSI_TCP is not set
# CONFIG_BLK_DEV_3W_XXXX_RAID is not set
# CONFIG_SCSI_3W_9XXX is not set
# CONFIG_SCSI_ACARD is not set
# CONFIG_SCSI_AACRAID is not set
# CONFIG_SCSI_AIC7XXX is not set
# CONFIG_SCSI_AIC7XXX_OLD is not set
# CONFIG_SCSI_AIC79XX is not set
# CONFIG_SCSI_AIC94XX is not set
# CONFIG_SCSI_DPT_I2O is not set
# CONFIG_SCSI_ADVANSYS is not set
# CONFIG_SCSI_ARCMSR is not set
# CONFIG_MEGARAID_NEWGEN is not set
# CONFIG_MEGARAID_LEGACY is not set
# CONFIG_MEGARAID_SAS is not set
# CONFIG_SCSI_HPTIOP is not set
# CONFIG_SCSI_BUSLOGIC is not set
# CONFIG_SCSI_DMX3191D is not set
# CONFIG_SCSI_EATA is not set
# CONFIG_SCSI_FUTURE_DOMAIN is not set
# CONFIG_SCSI_GDTH is not set
# CONFIG_SCSI_IPS is not set
# CONFIG_SCSI_INITIO is not set
# CONFIG_SCSI_INIA100 is not set
# CONFIG_SCSI_STEX is not set
# CONFIG_SCSI_SYM53C8XX_2 is not set
# CONFIG_SCSI_IPR is not set
# CONFIG_SCSI_QLOGIC_1280 is not set
# CONFIG_SCSI_QLA_FC is not set
# CONFIG_SCSI_QLA_ISCSI is not set
# CONFIG_SCSI_LPFC is not set
# CONFIG_SCSI_DC395x is not set
# CONFIG_SCSI_DC390T is not set
# CONFIG_SCSI_NSP32 is not set
# CONFIG_SCSI_DEBUG is not set
# CONFIG_SCSI_SRP is not set
# CONFIG_SCSI_LOWLEVEL_PCMCIA is not set
CONFIG_ATA=y
# CONFIG_ATA_NONSTANDARD is not set
CONFIG_ATA_ACPI=y
CONFIG_SATA_AHCI=y
# CONFIG_SATA_SVW is not set
CONFIG_ATA_PIIX=y
# CONFIG_SATA_MV is not set
# CONFIG_SATA_NV is not set
# CONFIG_PDC_ADMA is not set
# CONFIG_SATA_QSTOR is not set
# CONFIG_SATA_PROMISE is not set
# CONFIG_SATA_SX4 is not set
# CONFIG_SATA_SIL is not set
# CONFIG_SATA_SIL24 is not set
# CONFIG_SATA_SIS is not set
# CONFIG_SATA_ULI is not set
# CONFIG_SATA_VIA is not set
# CONFIG_SATA_VITESSE is not set
# CONFIG_SATA_INIC162X is not set
# CONFIG_PATA_ACPI is not set
# CONFIG_PATA_ALI is not set
# CONFIG_PATA_AMD is not set
# CONFIG_PATA_ARTOP is not set
# CONFIG_PATA_ATIIXP is not set
# CONFIG_PATA_CMD640_PCI is not set
# CONFIG_PATA_CMD64X is not set
# CONFIG_PATA_CS5520 is not set
# CONFIG_PATA_CS5530 is not set
# CONFIG_PATA_CS5535 is not set
# CONFIG_PATA_CS5536 is not set
# CONFIG_PATA_CYPRESS is not set
# CONFIG_PATA_EFAR is not set
# CONFIG_ATA_GENERIC is not set
# CONFIG_PATA_HPT366 is not set
# CONFIG_PATA_HPT37X is not set
# CONFIG_PATA_HPT3X2N is not set
# CONFIG_PATA_HPT3X3 is not set
# CONFIG_PATA_IT821X is not set
# CONFIG_PATA_IT8213 is not set
# CONFIG_PATA_JMICRON is not set
# CONFIG_PATA_TRIFLEX is not set
# CONFIG_PATA_MARVELL is not set
# CONFIG_PATA_MPIIX is not set
# CONFIG_PATA_OLDPIIX is not set
# CONFIG_PATA_NETCELL is not set
# CONFIG_PATA_NINJA32 is not set
# CONFIG_PATA_NS87410 is not set
# CONFIG_PATA_NS87415 is not set
# CONFIG_PATA_OPTI is not set
# CONFIG_PATA_OPTIDMA is not set
# CONFIG_PATA_PCMCIA is not set
# CONFIG_PATA_PDC_OLD is not set
# CONFIG_PATA_RADISYS is not set
# CONFIG_PATA_RZ1000 is not set
# CONFIG_PATA_SC1200 is not set
# CONFIG_PATA_SERVERWORKS is not set
# CONFIG_PATA_PDC2027X is not set
# CONFIG_PATA_SIL680 is not set
# CONFIG_PATA_SIS is not set
# CONFIG_PATA_VIA is not set
# CONFIG_PATA_WINBOND is not set
# CONFIG_MD is not set
# CONFIG_FUSION is not set

#
# IEEE 1394 (FireWire) support
#
# CONFIG_FIREWIRE is not set
# CONFIG_IEEE1394 is not set
# CONFIG_I2O is not set
# CONFIG_MACINTOSH_DRIVERS is not set
CONFIG_NETDEVICES=y
# CONFIG_NETDEVICES_MULTIQUEUE is not set
# CONFIG_DUMMY is not set
# CONFIG_BONDING is not set
# CONFIG_MACVLAN is not set
# CONFIG_EQUALIZER is not set
CONFIG_TUN=m
# CONFIG_VETH is not set
# CONFIG_NET_SB1000 is not set
# CONFIG_ARCNET is not set
# CONFIG_NET_ETHERNET is not set
CONFIG_NETDEV_1000=y
# CONFIG_ACENIC is not set
# CONFIG_DL2K is not set
CONFIG_E1000=m
CONFIG_E1000_NAPI=y
# CONFIG_E1000_DISABLE_PACKET_SPLIT is not set
# CONFIG_E1000E is not set
# CONFIG_E1000E_ENABLED is not set
# CONFIG_IP1000 is not set
# CONFIG_IGB is not set
# CONFIG_NS83820 is not set
# CONFIG_HAMACHI is not set
# CONFIG_YELLOWFIN is not set
# CONFIG_R8169 is not set
# CONFIG_SIS190 is not set
# CONFIG_SKGE is not set
# CONFIG_SKY2 is not set
# CONFIG_SK98LIN is not set
# CONFIG_VIA_VELOCITY is not set
CONFIG_TIGON3=m
# CONFIG_BNX2 is not set
# CONFIG_QLA3XXX is not set
# CONFIG_ATL1 is not set
# CONFIG_NETDEV_10000 is not set
# CONFIG_TR is not set

#
# Wireless LAN
#
# CONFIG_WLAN_PRE80211 is not set
CONFIG_WLAN_80211=y
# CONFIG_PCMCIA_RAYCS is not set
# CONFIG_IPW2100 is not set
CONFIG_IPW2200=m
CONFIG_IPW2200_MONITOR=y
CONFIG_IPW2200_RADIOTAP=y
CONFIG_IPW2200_PROMISCUOUS=y
# CONFIG_IPW2200_QOS is not set
# CONFIG_IPW2200_DEBUG is not set
# CONFIG_LIBERTAS is not set
# CONFIG_AIRO is not set
# CONFIG_HERMES is not set
# CONFIG_ATMEL is not set
# CONFIG_AIRO_CS is not set
# CONFIG_PCMCIA_WL3501 is not set
# CONFIG_PRISM54 is not set
# CONFIG_USB_ZD1201 is not set
# CONFIG_USB_NET_RNDIS_WLAN is not set
# CONFIG_RTL8180 is not set
# CONFIG_RTL8187 is not set
# CONFIG_ADM8211 is not set
# CONFIG_P54_COMMON is not set
# CONFIG_ATH5K is not set
# CONFIG_IWL4965 is not set
# CONFIG_IWL3945 is not set
# CONFIG_HOSTAP is not set
# CONFIG_B43 is not set
# CONFIG_B43LEGACY is not set
# CONFIG_ZD1211RW is not set
# CONFIG_RT2X00 is not set

#
# USB Network Adapters
#
# CONFIG_USB_CATC is not set
# CONFIG_USB_KAWETH is not set
# CONFIG_USB_PEGASUS is not set
# CONFIG_USB_RTL8150 is not set
# CONFIG_USB_USBNET is not set
# CONFIG_NET_PCMCIA is not set
# CONFIG_WAN is not set
# CONFIG_FDDI is not set
# CONFIG_HIPPI is not set
CONFIG_PPP=m
# CONFIG_PPP_MULTILINK is not set
CONFIG_PPP_FILTER=y
# CONFIG_PPP_ASYNC is not set
# CONFIG_PPP_SYNC_TTY is not set
CONFIG_PPP_DEFLATE=m
CONFIG_PPP_BSDCOMP=m
# CONFIG_PPP_MPPE is not set
# CONFIG_PPPOE is not set
# CONFIG_PPPOL2TP is not set
# CONFIG_SLIP is not set
CONFIG_SLHC=m
# CONFIG_NET_FC is not set
# CONFIG_NETCONSOLE is not set
# CONFIG_NETPOLL is not set
# CONFIG_NET_POLL_CONTROLLER is not set
# CONFIG_ISDN is not set
# CONFIG_PHONE is not set

#
# Input device support
#
CONFIG_INPUT=y
# CONFIG_INPUT_FF_MEMLESS is not set
# CONFIG_INPUT_POLLDEV is not set

#
# Userland interfaces
#
CONFIG_INPUT_MOUSEDEV=y
CONFIG_INPUT_MOUSEDEV_PSAUX=y
CONFIG_INPUT_MOUSEDEV_SCREEN_X=1024
CONFIG_INPUT_MOUSEDEV_SCREEN_Y=768
# CONFIG_INPUT_JOYDEV is not set
CONFIG_INPUT_EVDEV=m
# CONFIG_INPUT_EVBUG is not set

#
# Input Device Drivers
#
CONFIG_INPUT_KEYBOARD=y
CONFIG_KEYBOARD_ATKBD=y
# CONFIG_KEYBOARD_SUNKBD is not set
# CONFIG_KEYBOARD_LKKBD is not set
# CONFIG_KEYBOARD_XTKBD is not set
# CONFIG_KEYBOARD_NEWTON is not set
# CONFIG_KEYBOARD_STOWAWAY is not set
# CONFIG_INPUT_MOUSE is not set
# CONFIG_INPUT_JOYSTICK is not set
# CONFIG_INPUT_TABLET is not set
# CONFIG_INPUT_TOUCHSCREEN is not set
# CONFIG_INPUT_MISC is not set

#
# Hardware I/O ports
#
CONFIG_SERIO=y
CONFIG_SERIO_I8042=y
CONFIG_SERIO_SERPORT=y
# CONFIG_SERIO_CT82C710 is not set
# CONFIG_SERIO_PCIPS2 is not set
CONFIG_SERIO_LIBPS2=y
# CONFIG_SERIO_RAW is not set
# CONFIG_GAMEPORT is not set

#
# Character devices
#
CONFIG_VT=y
CONFIG_VT_CONSOLE=y
CONFIG_HW_CONSOLE=y
# CONFIG_VT_HW_CONSOLE_BINDING is not set
# CONFIG_SERIAL_NONSTANDARD is not set
# CONFIG_NOZOMI is not set

#
# Serial drivers
#
CONFIG_SERIAL_8250=y
CONFIG_SERIAL_8250_CONSOLE=y
CONFIG_FIX_EARLYCON_MEM=y
CONFIG_SERIAL_8250_PCI=y
CONFIG_SERIAL_8250_PNP=y
# CONFIG_SERIAL_8250_CS is not set
CONFIG_SERIAL_8250_NR_UARTS=4
CONFIG_SERIAL_8250_RUNTIME_UARTS=4
CONFIG_SERIAL_8250_EXTENDED=y
# CONFIG_SERIAL_8250_MANY_PORTS is not set
CONFIG_SERIAL_8250_SHARE_IRQ=y
# CONFIG_SERIAL_8250_DETECT_IRQ is not set
# CONFIG_SERIAL_8250_RSA is not set

#
# Non-8250 serial port support
#
CONFIG_SERIAL_CORE=y
CONFIG_SERIAL_CORE_CONSOLE=y
CONFIG_CONSOLE_POLL=y
# CONFIG_SERIAL_JSM is not set
CONFIG_UNIX98_PTYS=y
# CONFIG_LEGACY_PTYS is not set
# CONFIG_IPMI_HANDLER is not set
# CONFIG_HW_RANDOM is not set
# CONFIG_NVRAM is not set
CONFIG_RTC=y
# CONFIG_R3964 is not set
# CONFIG_APPLICOM is not set
# CONFIG_SONYPI is not set

#
# PCMCIA character devices
#
# CONFIG_SYNCLINK_CS is not set
# CONFIG_CARDMAN_4000 is not set
# CONFIG_CARDMAN_4040 is not set
# CONFIG_IPWIRELESS is not set
# CONFIG_MWAVE is not set
# CONFIG_PC8736x_GPIO is not set
# CONFIG_NSC_GPIO is not set
# CONFIG_CS5535_GPIO is not set
# CONFIG_RAW_DRIVER is not set
# CONFIG_HPET is not set
# CONFIG_HANGCHECK_TIMER is not set
# CONFIG_TCG_TPM is not set
# CONFIG_TELCLOCK is not set
CONFIG_DEVPORT=y
CONFIG_I2C=m
CONFIG_I2C_BOARDINFO=y
CONFIG_I2C_CHARDEV=m

#
# I2C Algorithms
#
CONFIG_I2C_ALGOBIT=m
# CONFIG_I2C_ALGOPCF is not set
# CONFIG_I2C_ALGOPCA is not set

#
# I2C Hardware Bus support
#
# CONFIG_I2C_ALI1535 is not set
# CONFIG_I2C_ALI1563 is not set
# CONFIG_I2C_ALI15X3 is not set
# CONFIG_I2C_AMD756 is not set
# CONFIG_I2C_AMD8111 is not set
# CONFIG_I2C_I801 is not set
# CONFIG_I2C_I810 is not set
# CONFIG_I2C_PIIX4 is not set
# CONFIG_I2C_NFORCE2 is not set
# CONFIG_I2C_OCORES is not set
# CONFIG_I2C_PARPORT_LIGHT is not set
# CONFIG_I2C_PROSAVAGE is not set
# CONFIG_I2C_SAVAGE4 is not set
# CONFIG_I2C_SIMTEC is not set
# CONFIG_SCx200_ACB is not set
# CONFIG_I2C_SIS5595 is not set
# CONFIG_I2C_SIS630 is not set
# CONFIG_I2C_SIS96X is not set
# CONFIG_I2C_TAOS_EVM is not set
# CONFIG_I2C_STUB is not set
# CONFIG_I2C_TINY_USB is not set
# CONFIG_I2C_VIA is not set
# CONFIG_I2C_VIAPRO is not set
# CONFIG_I2C_VOODOO3 is not set

#
# Miscellaneous I2C Chip support
#
# CONFIG_DS1682 is not set
# CONFIG_SENSORS_EEPROM is not set
# CONFIG_SENSORS_PCF8574 is not set
# CONFIG_PCF8575 is not set
# CONFIG_SENSORS_PCF8591 is not set
# CONFIG_TPS65010 is not set
# CONFIG_SENSORS_MAX6875 is not set
# CONFIG_SENSORS_TSL2550 is not set
# CONFIG_I2C_DEBUG_CORE is not set
# CONFIG_I2C_DEBUG_ALGO is not set
# CONFIG_I2C_DEBUG_BUS is not set
# CONFIG_I2C_DEBUG_CHIP is not set

#
# SPI support
#
# CONFIG_SPI is not set
# CONFIG_SPI_MASTER is not set
# CONFIG_W1 is not set
CONFIG_POWER_SUPPLY=y
# CONFIG_POWER_SUPPLY_DEBUG is not set
# CONFIG_PDA_POWER is not set
# CONFIG_BATTERY_DS2760 is not set
# CONFIG_HWMON is not set
CONFIG_THERMAL=y
# CONFIG_WATCHDOG is not set

#
# Sonics Silicon Backplane
#
CONFIG_SSB_POSSIBLE=y
# CONFIG_SSB is not set

#
# Multifunction device drivers
#
# CONFIG_MFD_SM501 is not set

#
# Multimedia devices
#
CONFIG_VIDEO_DEV=m
CONFIG_VIDEO_V4L1=y
CONFIG_VIDEO_V4L1_COMPAT=y
CONFIG_VIDEO_V4L2=y
CONFIG_VIDEO_CAPTURE_DRIVERS=y
# CONFIG_VIDEO_ADV_DEBUG is not set
CONFIG_VIDEO_HELPER_CHIPS_AUTO=y
CONFIG_VIDEO_TVAUDIO=m
CONFIG_VIDEO_TDA7432=m
CONFIG_VIDEO_TDA9875=m
CONFIG_VIDEO_MSP3400=m
CONFIG_VIDEO_SAA711X=m
CONFIG_VIDEO_TVP5150=m
# CONFIG_VIDEO_VIVI is not set
CONFIG_VIDEO_BT848=m
# CONFIG_VIDEO_BT848_DVB is not set
# CONFIG_VIDEO_SAA6588 is not set
# CONFIG_VIDEO_CPIA is not set
# CONFIG_VIDEO_CPIA2 is not set
# CONFIG_VIDEO_SAA5246A is not set
# CONFIG_VIDEO_SAA5249 is not set
# CONFIG_TUNER_3036 is not set
# CONFIG_VIDEO_STRADIS is not set
# CONFIG_VIDEO_ZORAN is not set
# CONFIG_VIDEO_SAA7134 is not set
# CONFIG_VIDEO_MXB is not set
# CONFIG_VIDEO_DPC is not set
# CONFIG_VIDEO_HEXIUM_ORION is not set
# CONFIG_VIDEO_HEXIUM_GEMINI is not set
# CONFIG_VIDEO_CX88 is not set
# CONFIG_VIDEO_CX23885 is not set
# CONFIG_VIDEO_IVTV is not set
# CONFIG_VIDEO_CAFE_CCIC is not set
CONFIG_V4L_USB_DRIVERS=y
# CONFIG_VIDEO_PVRUSB2 is not set
CONFIG_VIDEO_EM28XX=m
CONFIG_VIDEO_EM28XX_ALSA=m
# CONFIG_VIDEO_USBVISION is not set
# CONFIG_USB_VICAM is not set
# CONFIG_USB_IBMCAM is not set
# CONFIG_USB_KONICAWC is not set
# CONFIG_USB_QUICKCAM_MESSENGER is not set
# CONFIG_USB_ET61X251 is not set
# CONFIG_VIDEO_OVCAMCHIP is not set
# CONFIG_USB_W9968CF is not set
# CONFIG_USB_OV511 is not set
# CONFIG_USB_SE401 is not set
# CONFIG_USB_SN9C102 is not set
# CONFIG_USB_STV680 is not set
# CONFIG_USB_ZC0301 is not set
# CONFIG_USB_PWC is not set
# CONFIG_USB_ZR364XX is not set
# CONFIG_USB_STKWEBCAM is not set
# CONFIG_RADIO_ADAPTERS is not set
CONFIG_DVB_CORE=m
CONFIG_DVB_CORE_ATTACH=y
CONFIG_DVB_CAPTURE_DRIVERS=y

#
# Supported SAA7146 based PCI Adapters
#
# CONFIG_TTPCI_EEPROM is not set
# CONFIG_DVB_AV7110 is not set
# CONFIG_DVB_BUDGET_CORE is not set

#
# Supported USB Adapters
#
# CONFIG_DVB_USB is not set
# CONFIG_DVB_TTUSB_BUDGET is not set
# CONFIG_DVB_TTUSB_DEC is not set
CONFIG_DVB_CINERGYT2=m
# CONFIG_DVB_CINERGYT2_TUNING is not set

#
# Supported FlexCopII (B2C2) Adapters
#
# CONFIG_DVB_B2C2_FLEXCOP is not set

#
# Supported BT878 Adapters
#
CONFIG_DVB_BT8XX=m

#
# Supported Pluto2 Adapters
#
# CONFIG_DVB_PLUTO2 is not set

#
# Supported DVB Frontends
#

#
# Customise DVB Frontends
#
# CONFIG_DVB_FE_CUSTOMISE is not set

#
# DVB-S (satellite) frontends
#
# CONFIG_DVB_STV0299 is not set
CONFIG_DVB_CX24110=m
# CONFIG_DVB_CX24123 is not set
# CONFIG_DVB_TDA8083 is not set
# CONFIG_DVB_MT312 is not set
# CONFIG_DVB_VES1X93 is not set
# CONFIG_DVB_S5H1420 is not set
# CONFIG_DVB_TDA10086 is not set

#
# DVB-T (terrestrial) frontends
#
# CONFIG_DVB_SP8870 is not set
CONFIG_DVB_SP887X=m
# CONFIG_DVB_CX22700 is not set
# CONFIG_DVB_CX22702 is not set
# CONFIG_DVB_L64781 is not set
# CONFIG_DVB_TDA1004X is not set
CONFIG_DVB_NXT6000=m
CONFIG_DVB_MT352=m
CONFIG_DVB_ZL10353=m
# CONFIG_DVB_DIB3000MB is not set
# CONFIG_DVB_DIB3000MC is not set
# CONFIG_DVB_DIB7000M is not set
# CONFIG_DVB_DIB7000P is not set

#
# DVB-C (cable) frontends
#
# CONFIG_DVB_VES1820 is not set
# CONFIG_DVB_TDA10021 is not set
# CONFIG_DVB_TDA10023 is not set
# CONFIG_DVB_STV0297 is not set

#
# ATSC (North American/Korean Terrestrial/Cable DTV) frontends
#
# CONFIG_DVB_NXT200X is not set
CONFIG_DVB_OR51211=m
# CONFIG_DVB_OR51132 is not set
# CONFIG_DVB_BCM3510 is not set
CONFIG_DVB_LGDT330X=m
# CONFIG_DVB_S5H1409 is not set

#
# Tuners/PLL support
#
CONFIG_DVB_PLL=m
# CONFIG_DVB_TDA826X is not set
# CONFIG_DVB_TDA827X is not set
# CONFIG_DVB_TDA18271 is not set
# CONFIG_DVB_TUNER_QT1010 is not set
# CONFIG_DVB_TUNER_MT2060 is not set
# CONFIG_DVB_TUNER_MT2266 is not set
# CONFIG_DVB_TUNER_MT2131 is not set
# CONFIG_DVB_TUNER_DIB0070 is not set
# CONFIG_DVB_TUNER_XC5000 is not set

#
# Miscellaneous devices
#
# CONFIG_DVB_LNBP21 is not set
# CONFIG_DVB_ISL6421 is not set
# CONFIG_DVB_TUA6100 is not set
CONFIG_VIDEO_TUNER=m
# CONFIG_VIDEO_TUNER_CUSTOMIZE is not set
CONFIG_TUNER_XC2028=m
CONFIG_TUNER_MT20XX=m
CONFIG_TUNER_TDA8290=m
CONFIG_TUNER_TEA5761=m
CONFIG_TUNER_TEA5767=m
CONFIG_TUNER_SIMPLE=m
CONFIG_TUNER_TDA9887=m
CONFIG_VIDEOBUF_GEN=m
CONFIG_VIDEOBUF_DMA_SG=m
CONFIG_VIDEO_BTCX=m
CONFIG_VIDEO_IR_I2C=m
CONFIG_VIDEO_IR=m
CONFIG_VIDEO_TVEEPROM=m
# CONFIG_DAB is not set

#
# Graphics support
#
CONFIG_AGP=m
# CONFIG_AGP_ALI is not set
# CONFIG_AGP_ATI is not set
# CONFIG_AGP_AMD is not set
# CONFIG_AGP_AMD64 is not set
CONFIG_AGP_INTEL=m
# CONFIG_AGP_NVIDIA is not set
# CONFIG_AGP_SIS is not set
# CONFIG_AGP_SWORKS is not set
# CONFIG_AGP_VIA is not set
# CONFIG_AGP_EFFICEON is not set
CONFIG_DRM=m
# CONFIG_DRM_TDFX is not set
# CONFIG_DRM_R128 is not set
# CONFIG_DRM_RADEON is not set
# CONFIG_DRM_I810 is not set
# CONFIG_DRM_I830 is not set
CONFIG_DRM_I915=m
# CONFIG_DRM_MGA is not set
# CONFIG_DRM_SIS is not set
# CONFIG_DRM_VIA is not set
# CONFIG_DRM_SAVAGE is not set
# CONFIG_VGASTATE is not set
# CONFIG_VIDEO_OUTPUT_CONTROL is not set
# CONFIG_FB is not set
# CONFIG_BACKLIGHT_LCD_SUPPORT is not set

#
# Display device support
#
# CONFIG_DISPLAY_SUPPORT is not set

#
# Console display driver support
#
CONFIG_VGA_CONSOLE=y
# CONFIG_VGACON_SOFT_SCROLLBACK is not set
CONFIG_VIDEO_SELECT=y
CONFIG_DUMMY_CONSOLE=y

#
# Sound
#
CONFIG_SOUND=m

#
# Advanced Linux Sound Architecture
#
CONFIG_SND=m
CONFIG_SND_TIMER=m
CONFIG_SND_PCM=m
CONFIG_SND_RAWMIDI=m
# CONFIG_SND_SEQUENCER is not set
# CONFIG_SND_MIXER_OSS is not set
# CONFIG_SND_PCM_OSS is not set
CONFIG_SND_RTCTIMER=m
# CONFIG_SND_DYNAMIC_MINORS is not set
CONFIG_SND_SUPPORT_OLD_API=y
CONFIG_SND_VERBOSE_PROCFS=y
# CONFIG_SND_VERBOSE_PRINTK is not set
# CONFIG_SND_DEBUG is not set

#
# Generic devices
#
CONFIG_SND_AC97_CODEC=m
# CONFIG_SND_DUMMY is not set
# CONFIG_SND_MTPAV is not set
# CONFIG_SND_SERIAL_U16550 is not set
# CONFIG_SND_MPU401 is not set

#
# PCI devices
#
# CONFIG_SND_AD1889 is not set
# CONFIG_SND_ALS300 is not set
# CONFIG_SND_ALS4000 is not set
# CONFIG_SND_ALI5451 is not set
# CONFIG_SND_ATIIXP is not set
# CONFIG_SND_ATIIXP_MODEM is not set
# CONFIG_SND_AU8810 is not set
# CONFIG_SND_AU8820 is not set
# CONFIG_SND_AU8830 is not set
# CONFIG_SND_AZT3328 is not set
CONFIG_SND_BT87X=m
# CONFIG_SND_BT87X_OVERCLOCK is not set
# CONFIG_SND_CA0106 is not set
# CONFIG_SND_CMIPCI is not set
# CONFIG_SND_OXYGEN is not set
# CONFIG_SND_CS4281 is not set
# CONFIG_SND_CS46XX is not set
# CONFIG_SND_CS5530 is not set
# CONFIG_SND_CS5535AUDIO is not set
# CONFIG_SND_DARLA20 is not set
# CONFIG_SND_GINA20 is not set
# CONFIG_SND_LAYLA20 is not set
# CONFIG_SND_DARLA24 is not set
# CONFIG_SND_GINA24 is not set
# CONFIG_SND_LAYLA24 is not set
# CONFIG_SND_MONA is not set
# CONFIG_SND_MIA is not set
# CONFIG_SND_ECHO3G is not set
# CONFIG_SND_INDIGO is not set
# CONFIG_SND_INDIGOIO is not set
# CONFIG_SND_INDIGODJ is not set
# CONFIG_SND_EMU10K1 is not set
# CONFIG_SND_EMU10K1X is not set
# CONFIG_SND_ENS1370 is not set
CONFIG_SND_ENS1371=m
# CONFIG_SND_ES1938 is not set
# CONFIG_SND_ES1968 is not set
# CONFIG_SND_FM801 is not set
# CONFIG_SND_HDA_INTEL is not set
# CONFIG_SND_HDSP is not set
# CONFIG_SND_HDSPM is not set
# CONFIG_SND_HIFIER is not set
# CONFIG_SND_ICE1712 is not set
# CONFIG_SND_ICE1724 is not set
CONFIG_SND_INTEL8X0=m
# CONFIG_SND_INTEL8X0M is not set
# CONFIG_SND_KORG1212 is not set
# CONFIG_SND_MAESTRO3 is not set
# CONFIG_SND_MIXART is not set
# CONFIG_SND_NM256 is not set
# CONFIG_SND_PCXHR is not set
# CONFIG_SND_RIPTIDE is not set
# CONFIG_SND_RME32 is not set
# CONFIG_SND_RME96 is not set
# CONFIG_SND_RME9652 is not set
# CONFIG_SND_SIS7019 is not set
# CONFIG_SND_SONICVIBES is not set
# CONFIG_SND_TRIDENT is not set
# CONFIG_SND_VIA82XX is not set
# CONFIG_SND_VIA82XX_MODEM is not set
# CONFIG_SND_VIRTUOSO is not set
# CONFIG_SND_VX222 is not set
# CONFIG_SND_YMFPCI is not set
# CONFIG_SND_AC97_POWER_SAVE is not set

#
# USB devices
#
# CONFIG_SND_USB_AUDIO is not set
# CONFIG_SND_USB_USX2Y is not set
# CONFIG_SND_USB_CAIAQ is not set

#
# PCMCIA devices
#
# CONFIG_SND_VXPOCKET is not set
# CONFIG_SND_PDAUDIOCF is not set

#
# System on Chip audio support
#
# CONFIG_SND_SOC is not set

#
# SoC Audio support for SuperH
#

#
# ALSA SoC audio for Freescale SOCs
#

#
# Open Sound System
#
# CONFIG_SOUND_PRIME is not set
CONFIG_AC97_BUS=m
CONFIG_HID_SUPPORT=y
CONFIG_HID=y
CONFIG_HID_DEBUG=y
# CONFIG_HIDRAW is not set

#
# USB Input Devices
#
CONFIG_USB_HID=y
# CONFIG_USB_HIDINPUT_POWERBOOK is not set
# CONFIG_HID_FF is not set
# CONFIG_USB_HIDDEV is not set
CONFIG_USB_SUPPORT=y
CONFIG_USB_ARCH_HAS_HCD=y
CONFIG_USB_ARCH_HAS_OHCI=y
CONFIG_USB_ARCH_HAS_EHCI=y
CONFIG_USB=y
# CONFIG_USB_DEBUG is not set
# CONFIG_USB_ANNOUNCE_NEW_DEVICES is not set

#
# Miscellaneous USB options
#
CONFIG_USB_DEVICEFS=y
CONFIG_USB_DEVICE_CLASS=y
# CONFIG_USB_DYNAMIC_MINORS is not set
# CONFIG_USB_SUSPEND is not set
# CONFIG_USB_PERSIST is not set
# CONFIG_USB_OTG is not set

#
# USB Host Controller Drivers
#
CONFIG_USB_EHCI_HCD=y
# CONFIG_USB_EHCI_ROOT_HUB_TT is not set
# CONFIG_USB_EHCI_TT_NEWSCHED is not set
# CONFIG_USB_ISP116X_HCD is not set
# CONFIG_USB_OHCI_HCD is not set
CONFIG_USB_UHCI_HCD=y
# CONFIG_USB_SL811_HCD is not set
# CONFIG_USB_R8A66597_HCD is not set

#
# USB Device Class drivers
#
# CONFIG_USB_ACM is not set
# CONFIG_USB_PRINTER is not set

#
# NOTE: USB_STORAGE enables SCSI, and 'SCSI disk support'
#

#
# may also be needed; see USB_STORAGE Help for more information
#
CONFIG_USB_STORAGE=y
# CONFIG_USB_STORAGE_DEBUG is not set
# CONFIG_USB_STORAGE_DATAFAB is not set
# CONFIG_USB_STORAGE_FREECOM is not set
# CONFIG_USB_STORAGE_ISD200 is not set
# CONFIG_USB_STORAGE_DPCM is not set
# CONFIG_USB_STORAGE_USBAT is not set
# CONFIG_USB_STORAGE_SDDR09 is not set
# CONFIG_USB_STORAGE_SDDR55 is not set
# CONFIG_USB_STORAGE_JUMPSHOT is not set
# CONFIG_USB_STORAGE_ALAUDA is not set
# CONFIG_USB_STORAGE_KARMA is not set
# CONFIG_USB_LIBUSUAL is not set

#
# USB Imaging devices
#
# CONFIG_USB_MDC800 is not set
# CONFIG_USB_MICROTEK is not set
# CONFIG_USB_MON is not set

#
# USB port drivers
#
# CONFIG_USB_SERIAL is not set

#
# USB Miscellaneous drivers
#
# CONFIG_USB_EMI62 is not set
# CONFIG_USB_EMI26 is not set
# CONFIG_USB_ADUTUX is not set
# CONFIG_USB_AUERSWALD is not set
# CONFIG_USB_RIO500 is not set
# CONFIG_USB_LEGOTOWER is not set
# CONFIG_USB_LCD is not set
# CONFIG_USB_BERRY_CHARGE is not set
# CONFIG_USB_LED is not set
# CONFIG_USB_CYPRESS_CY7C63 is not set
# CONFIG_USB_CYTHERM is not set
# CONFIG_USB_PHIDGET is not set
# CONFIG_USB_IDMOUSE is not set
# CONFIG_USB_FTDI_ELAN is not set
# CONFIG_USB_APPLEDISPLAY is not set
# CONFIG_USB_SISUSBVGA is not set
# CONFIG_USB_LD is not set
# CONFIG_USB_TRANCEVIBRATOR is not set
# CONFIG_USB_IOWARRIOR is not set
# CONFIG_USB_TEST is not set
# CONFIG_USB_GADGET is not set
# CONFIG_MMC is not set
# CONFIG_MEMSTICK is not set
# CONFIG_NEW_LEDS is not set
# CONFIG_INFINIBAND is not set
# CONFIG_EDAC is not set
# CONFIG_RTC_CLASS is not set
# CONFIG_DMADEVICES is not set

#
# Userspace I/O
#
# CONFIG_UIO is not set

#
# Firmware Drivers
#
# CONFIG_EDD is not set
# CONFIG_DELL_RBU is not set
# CONFIG_DCDBAS is not set
# CONFIG_DMIID is not set

#
# File systems
#
CONFIG_EXT2_FS=y
# CONFIG_EXT2_FS_XATTR is not set
# CONFIG_EXT2_FS_XIP is not set
CONFIG_EXT3_FS=y
# CONFIG_EXT3_FS_XATTR is not set
# CONFIG_EXT4DEV_FS is not set
CONFIG_JBD=y
CONFIG_REISERFS_FS=y
# CONFIG_REISERFS_CHECK is not set
# CONFIG_REISERFS_PROC_INFO is not set
# CONFIG_REISERFS_FS_XATTR is not set
# CONFIG_JFS_FS is not set
# CONFIG_FS_POSIX_ACL is not set
# CONFIG_XFS_FS is not set
# CONFIG_GFS2_FS is not set
# CONFIG_OCFS2_FS is not set
CONFIG_DNOTIFY=y
CONFIG_INOTIFY=y
CONFIG_INOTIFY_USER=y
# CONFIG_QUOTA is not set
# CONFIG_AUTOFS_FS is not set
# CONFIG_AUTOFS4_FS is not set
CONFIG_FUSE_FS=m

#
# CD-ROM/DVD Filesystems
#
CONFIG_ISO9660_FS=m
CONFIG_JOLIET=y
CONFIG_ZISOFS=y
# CONFIG_UDF_FS is not set

#
# DOS/FAT/NT Filesystems
#
CONFIG_FAT_FS=m
CONFIG_MSDOS_FS=m
CONFIG_VFAT_FS=m
CONFIG_FAT_DEFAULT_CODEPAGE=437
CONFIG_FAT_DEFAULT_IOCHARSET="iso8859-1"
# CONFIG_NTFS_FS is not set

#
# Pseudo filesystems
#
CONFIG_PROC_FS=y
# CONFIG_PROC_KCORE is not set
CONFIG_PROC_SYSCTL=y
CONFIG_SYSFS=y
CONFIG_TMPFS=y
# CONFIG_TMPFS_POSIX_ACL is not set
# CONFIG_HUGETLBFS is not set
# CONFIG_HUGETLB_PAGE is not set
# CONFIG_CONFIGFS_FS is not set

#
# Miscellaneous filesystems
#
# CONFIG_ADFS_FS is not set
# CONFIG_AFFS_FS is not set
# CONFIG_HFS_FS is not set
# CONFIG_HFSPLUS_FS is not set
# CONFIG_BEFS_FS is not set
# CONFIG_BFS_FS is not set
# CONFIG_EFS_FS is not set
# CONFIG_CRAMFS is not set
# CONFIG_VXFS_FS is not set
# CONFIG_MINIX_FS is not set
# CONFIG_HPFS_FS is not set
# CONFIG_QNX4FS_FS is not set
# CONFIG_ROMFS_FS is not set
# CONFIG_SYSV_FS is not set
# CONFIG_UFS_FS is not set
CONFIG_NETWORK_FILESYSTEMS=y
# CONFIG_NFS_FS is not set
# CONFIG_NFSD is not set
# CONFIG_SMB_FS is not set
# CONFIG_CIFS is not set
# CONFIG_NCP_FS is not set
# CONFIG_CODA_FS is not set
# CONFIG_AFS_FS is not set

#
# Partition Types
#
# CONFIG_PARTITION_ADVANCED is not set
CONFIG_MSDOS_PARTITION=y
CONFIG_NLS=m
CONFIG_NLS_DEFAULT="iso8859-1"
CONFIG_NLS_CODEPAGE_437=m
# CONFIG_NLS_CODEPAGE_737 is not set
# CONFIG_NLS_CODEPAGE_775 is not set
CONFIG_NLS_CODEPAGE_850=m
# CONFIG_NLS_CODEPAGE_852 is not set
# CONFIG_NLS_CODEPAGE_855 is not set
# CONFIG_NLS_CODEPAGE_857 is not set
# CONFIG_NLS_CODEPAGE_860 is not set
# CONFIG_NLS_CODEPAGE_861 is not set
# CONFIG_NLS_CODEPAGE_862 is not set
# CONFIG_NLS_CODEPAGE_863 is not set
# CONFIG_NLS_CODEPAGE_864 is not set
# CONFIG_NLS_CODEPAGE_865 is not set
# CONFIG_NLS_CODEPAGE_866 is not set
# CONFIG_NLS_CODEPAGE_869 is not set
# CONFIG_NLS_CODEPAGE_936 is not set
# CONFIG_NLS_CODEPAGE_950 is not set
# CONFIG_NLS_CODEPAGE_932 is not set
# CONFIG_NLS_CODEPAGE_949 is not set
# CONFIG_NLS_CODEPAGE_874 is not set
# CONFIG_NLS_ISO8859_8 is not set
# CONFIG_NLS_CODEPAGE_1250 is not set
# CONFIG_NLS_CODEPAGE_1251 is not set
# CONFIG_NLS_ASCII is not set
CONFIG_NLS_ISO8859_1=m
# CONFIG_NLS_ISO8859_2 is not set
# CONFIG_NLS_ISO8859_3 is not set
# CONFIG_NLS_ISO8859_4 is not set
# CONFIG_NLS_ISO8859_5 is not set
# CONFIG_NLS_ISO8859_6 is not set
# CONFIG_NLS_ISO8859_7 is not set
# CONFIG_NLS_ISO8859_9 is not set
# CONFIG_NLS_ISO8859_13 is not set
# CONFIG_NLS_ISO8859_14 is not set
# CONFIG_NLS_ISO8859_15 is not set
# CONFIG_NLS_KOI8_R is not set
# CONFIG_NLS_KOI8_U is not set
CONFIG_NLS_UTF8=m
# CONFIG_DLM is not set

#
# Kernel hacking
#
CONFIG_TRACE_IRQFLAGS_SUPPORT=y
# CONFIG_PRINTK_TIME is not set
CONFIG_ENABLE_WARN_DEPRECATED=y
CONFIG_ENABLE_MUST_CHECK=y
CONFIG_MAGIC_SYSRQ=y
# CONFIG_UNUSED_SYMBOLS is not set
# CONFIG_DEBUG_FS is not set
# CONFIG_HEADERS_CHECK is not set
CONFIG_DEBUG_KERNEL=y
# CONFIG_DEBUG_SHIRQ is not set
CONFIG_DETECT_SOFTLOCKUP=y
CONFIG_SCHED_DEBUG=y
# CONFIG_SCHEDSTATS is not set
# CONFIG_TIMER_STATS is not set
# CONFIG_SLUB_DEBUG_ON is not set
# CONFIG_SLUB_STATS is not set
CONFIG_DEBUG_PREEMPT=y
# CONFIG_DEBUG_RT_MUTEXES is not set
# CONFIG_RT_MUTEX_TESTER is not set
CONFIG_DEBUG_SPINLOCK=y
CONFIG_DEBUG_MUTEXES=y
CONFIG_DEBUG_LOCK_ALLOC=y
# CONFIG_PROVE_LOCKING is not set
CONFIG_LOCKDEP=y
# CONFIG_LOCK_STAT is not set
# CONFIG_DEBUG_LOCKDEP is not set
# CONFIG_DEBUG_SPINLOCK_SLEEP is not set
# CONFIG_DEBUG_LOCKING_API_SELFTESTS is not set
CONFIG_STACKTRACE=y
# CONFIG_DEBUG_KOBJECT is not set
# CONFIG_DEBUG_HIGHMEM is not set
CONFIG_DEBUG_BUGVERBOSE=y
CONFIG_DEBUG_INFO=y
# CONFIG_DEBUG_VM is not set
# CONFIG_DEBUG_LIST is not set
# CONFIG_DEBUG_SG is not set
CONFIG_FRAME_POINTER=y
# CONFIG_BOOT_PRINTK_DELAY is not set
# CONFIG_RCU_TORTURE_TEST is not set
# CONFIG_BACKTRACE_SELF_TEST is not set
# CONFIG_FAULT_INJECTION is not set
# CONFIG_LATENCYTOP is not set
# CONFIG_PROVIDE_OHCI1394_DMA_INIT is not set
# CONFIG_SAMPLES is not set
CONFIG_KGDB=y
CONFIG_HAVE_ARCH_KGDB=y
CONFIG_KGDB_SERIAL_CONSOLE=y
CONFIG_EARLY_PRINTK=y
# CONFIG_DEBUG_STACKOVERFLOW is not set
# CONFIG_DEBUG_STACK_USAGE is not set
# CONFIG_DEBUG_PAGEALLOC is not set
CONFIG_DEBUG_RODATA=y
# CONFIG_DEBUG_RODATA_TEST is not set
# CONFIG_DEBUG_NX_TEST is not set
# CONFIG_4KSTACKS is not set
CONFIG_X86_FIND_SMP_CONFIG=y
CONFIG_X86_MPPARSE=y
CONFIG_DOUBLEFAULT=y
CONFIG_IO_DELAY_TYPE_0X80=0
CONFIG_IO_DELAY_TYPE_0XED=1
CONFIG_IO_DELAY_TYPE_UDELAY=2
CONFIG_IO_DELAY_TYPE_NONE=3
# CONFIG_IO_DELAY_0X80 is not set
CONFIG_IO_DELAY_0XED=y
# CONFIG_IO_DELAY_UDELAY is not set
# CONFIG_IO_DELAY_NONE is not set
CONFIG_DEFAULT_IO_DELAY_TYPE=1
# CONFIG_CPA_DEBUG is not set

#
# Security options
#
# CONFIG_KEYS is not set
CONFIG_SECURITY=y
# CONFIG_SECURITY_NETWORK is not set
CONFIG_SECURITY_CAPABILITIES=y
# CONFIG_SECURITY_FILE_CAPABILITIES is not set
# CONFIG_SECURITY_ROOTPLUG is not set
CONFIG_SECURITY_DEFAULT_MMAP_MIN_ADDR=0
CONFIG_CRYPTO=y
CONFIG_CRYPTO_ALGAPI=y
CONFIG_CRYPTO_BLKCIPHER=y
# CONFIG_CRYPTO_SEQIV is not set
CONFIG_CRYPTO_MANAGER=y
# CONFIG_CRYPTO_HMAC is not set
# CONFIG_CRYPTO_XCBC is not set
# CONFIG_CRYPTO_NULL is not set
# CONFIG_CRYPTO_MD4 is not set
# CONFIG_CRYPTO_MD5 is not set
# CONFIG_CRYPTO_SHA1 is not set
# CONFIG_CRYPTO_SHA256 is not set
# CONFIG_CRYPTO_SHA512 is not set
# CONFIG_CRYPTO_WP512 is not set
# CONFIG_CRYPTO_TGR192 is not set
# CONFIG_CRYPTO_GF128MUL is not set
CONFIG_CRYPTO_ECB=m
CONFIG_CRYPTO_CBC=y
# CONFIG_CRYPTO_PCBC is not set
# CONFIG_CRYPTO_LRW is not set
# CONFIG_CRYPTO_XTS is not set
# CONFIG_CRYPTO_CTR is not set
# CONFIG_CRYPTO_GCM is not set
# CONFIG_CRYPTO_CCM is not set
# CONFIG_CRYPTO_CRYPTD is not set
# CONFIG_CRYPTO_DES is not set
# CONFIG_CRYPTO_FCRYPT is not set
# CONFIG_CRYPTO_BLOWFISH is not set
# CONFIG_CRYPTO_TWOFISH is not set
# CONFIG_CRYPTO_TWOFISH_586 is not set
# CONFIG_CRYPTO_SERPENT is not set
CONFIG_CRYPTO_AES=m
# CONFIG_CRYPTO_AES_586 is not set
# CONFIG_CRYPTO_CAST5 is not set
# CONFIG_CRYPTO_CAST6 is not set
# CONFIG_CRYPTO_TEA is not set
CONFIG_CRYPTO_ARC4=m
# CONFIG_CRYPTO_KHAZAD is not set
# CONFIG_CRYPTO_ANUBIS is not set
# CONFIG_CRYPTO_SEED is not set
# CONFIG_CRYPTO_SALSA20 is not set
# CONFIG_CRYPTO_SALSA20_586 is not set
# CONFIG_CRYPTO_DEFLATE is not set
# CONFIG_CRYPTO_MICHAEL_MIC is not set
# CONFIG_CRYPTO_CRC32C is not set
# CONFIG_CRYPTO_CAMELLIA is not set
# CONFIG_CRYPTO_TEST is not set
# CONFIG_CRYPTO_AUTHENC is not set
# CONFIG_CRYPTO_LZO is not set
CONFIG_CRYPTO_HW=y
# CONFIG_CRYPTO_DEV_PADLOCK is not set
# CONFIG_CRYPTO_DEV_GEODE is not set
# CONFIG_CRYPTO_DEV_HIFN_795X is not set
# CONFIG_VIRTUALIZATION is not set

#
# Library routines
#
CONFIG_BITREVERSE=m
# CONFIG_CRC_CCITT is not set
# CONFIG_CRC16 is not set
# CONFIG_CRC_ITU_T is not set
CONFIG_CRC32=m
# CONFIG_CRC7 is not set
# CONFIG_LIBCRC32C is not set
CONFIG_ZLIB_INFLATE=m
CONFIG_ZLIB_DEFLATE=m
CONFIG_PLIST=y
CONFIG_HAS_IOMEM=y
CONFIG_HAS_IOPORT=y
CONFIG_HAS_DMA=y


-----[ Domenico Andreoli, aka cavok
 --[ http://www.dandreoli.com/gpgkey.asc
   ---[ 3A0F 2F80 F79C 678A 8936  4FEE 0677 9033 A20E BC50

Re: kgdb in git-x86#mm review

[Mark Lord]

Andi Kleen wrote:
> ..
> You should probably use simple_strtoul() instead of inventing an
> own hex parser in kgdb.c. And sprintf instead of an own hex writer.
> In general more use sprintf would probably shorten a lot of the parser
> code.
..

Speaking of which.. the kernel implementation of snprintf() seems
to have a bug somewhere, in that it returns an incorrect count in
some situations -- mostly around where the buffer is too small to
hold the data being written.  There's an off-by-one bug there somewhere,
but I have not had time yet to track it down more precisely.

Cheers