* [Patch 1/6] Prepare the PowerPC platform for HW Breakpoint infrastructure
[not found] <20090726235854.574539012@prasadkr_t60p.in.ibm.com>
@ 2009-07-27 0:12 ` K.Prasad
2009-07-27 0:13 ` [Patch 2/6] Introduce PPC64 specific Hardware Breakpoint interfaces K.Prasad
` (4 subsequent siblings)
5 siblings, 0 replies; 15+ messages in thread
From: K.Prasad @ 2009-07-27 0:12 UTC (permalink / raw)
To: David Gibson, linuxppc-dev
Cc: Michael Neuling, Benjamin Herrenschmidt, paulus, Alan Stern,
K.Prasad, Roland McGrath
Prepare the PowerPC code for HW Breakpoint infrastructure patches by including
relevant constant definitions and function declarations.
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/hw_breakpoint.h | 59 +++++++++++++++++++++++++++++++
arch/powerpc/include/asm/processor.h | 1
arch/powerpc/include/asm/reg.h | 3 +
arch/powerpc/include/asm/thread_info.h | 2 +
4 files changed, 65 insertions(+)
Index: linux-2.6-tip.hbkpt/arch/powerpc/include/asm/hw_breakpoint.h
===================================================================
--- /dev/null
+++ linux-2.6-tip.hbkpt/arch/powerpc/include/asm/hw_breakpoint.h
@@ -0,0 +1,59 @@
+#ifndef _PPC64_HW_BREAKPOINT_H
+#define _PPC64_HW_BREAKPOINT_H
+
+#ifdef __KERNEL__
+#define __ARCH_HW_BREAKPOINT_H
+#ifdef CONFIG_PPC64
+
+struct arch_hw_breakpoint {
+ char *name; /* Contains name of the symbol to set bkpt */
+ unsigned long address;
+ int type;
+ unsigned long symbolsize;
+};
+
+#include <linux/kdebug.h>
+#include <asm/reg.h>
+#include <asm-generic/hw_breakpoint.h>
+
+#define HW_BREAKPOINT_READ DABR_DATA_READ
+#define HW_BREAKPOINT_WRITE DABR_DATA_WRITE
+#define HW_BREAKPOINT_RW (DABR_DATA_READ | DABR_DATA_WRITE)
+
+#define HW_BREAKPOINT_ALIGN 0x7
+#define HW_BREAKPOINT_LEN INSTRUCTION_LEN
+
+extern struct hw_breakpoint *hbp_kernel[HBP_NUM];
+DECLARE_PER_CPU(struct hw_breakpoint*, this_hbp_kernel[HBP_NUM]);
+extern unsigned int hbp_user_refcount[HBP_NUM];
+
+extern void arch_install_thread_hw_breakpoint(struct task_struct *tsk);
+extern void arch_uninstall_thread_hw_breakpoint(void);
+extern int arch_validate_hwbkpt_settings(struct hw_breakpoint *bp,
+ struct task_struct *tsk);
+extern void arch_update_user_hw_breakpoint(int pos, struct task_struct *tsk);
+extern void arch_flush_thread_hw_breakpoint(struct task_struct *tsk);
+extern void arch_update_kernel_hw_breakpoint(void *);
+extern int hw_breakpoint_exceptions_notify(struct notifier_block *unused,
+ unsigned long val, void *data);
+
+extern void flush_thread_hw_breakpoint(struct task_struct *tsk);
+extern int copy_thread_hw_breakpoint(struct task_struct *tsk,
+ struct task_struct *child, unsigned long clone_flags);
+extern void load_debug_registers(void);
+extern void ptrace_triggered(struct hw_breakpoint *bp, struct pt_regs *regs);
+
+static inline void hw_breakpoint_disable(void)
+{
+ set_dabr(0);
+}
+
+#else
+static inline void hw_breakpoint_disable(void)
+{
+ /* Function is defined only on PPC64 for now */
+}
+#endif /* CONFIG_PPC64 */
+#endif /* __KERNEL__ */
+#endif /* _PPC64_HW_BREAKPOINT_H */
+
Index: linux-2.6-tip.hbkpt/arch/powerpc/include/asm/processor.h
===================================================================
--- linux-2.6-tip.hbkpt.orig/arch/powerpc/include/asm/processor.h
+++ linux-2.6-tip.hbkpt/arch/powerpc/include/asm/processor.h
@@ -177,6 +177,7 @@ struct thread_struct {
#ifdef CONFIG_PPC64
unsigned long start_tb; /* Start purr when proc switched in */
unsigned long accum_tb; /* Total accumilated purr for process */
+ struct hw_breakpoint *hbp[HBP_NUM];
#endif
unsigned long dabr; /* Data address breakpoint register */
#ifdef CONFIG_ALTIVEC
Index: linux-2.6-tip.hbkpt/arch/powerpc/include/asm/reg.h
===================================================================
--- linux-2.6-tip.hbkpt.orig/arch/powerpc/include/asm/reg.h
+++ linux-2.6-tip.hbkpt/arch/powerpc/include/asm/reg.h
@@ -26,6 +26,8 @@
#include <asm/reg_8xx.h>
#endif /* CONFIG_8xx */
+#define INSTRUCTION_LEN 4 /* Length of any instruction */
+
#define MSR_SF_LG 63 /* Enable 64 bit mode */
#define MSR_ISF_LG 61 /* Interrupt 64b mode valid on 630 */
#define MSR_HV_LG 60 /* Hypervisor state */
@@ -184,6 +186,7 @@
#define CTRL_TE 0x00c00000 /* thread enable */
#define CTRL_RUNLATCH 0x1
#define SPRN_DABR 0x3F5 /* Data Address Breakpoint Register */
+#define HBP_NUM 1 /* Number of physical HW breakpoint registers */
#define DABR_TRANSLATION (1UL << 2)
#define DABR_DATA_WRITE (1UL << 1)
#define DABR_DATA_READ (1UL << 0)
Index: linux-2.6-tip.hbkpt/arch/powerpc/include/asm/thread_info.h
===================================================================
--- linux-2.6-tip.hbkpt.orig/arch/powerpc/include/asm/thread_info.h
+++ linux-2.6-tip.hbkpt/arch/powerpc/include/asm/thread_info.h
@@ -112,6 +112,7 @@ static inline struct thread_info *curren
#define TIF_FREEZE 14 /* Freezing for suspend */
#define TIF_RUNLATCH 15 /* Is the runlatch enabled? */
#define TIF_ABI_PENDING 16 /* 32/64 bit switch needed */
+#define TIF_DEBUG 17 /* uses debug registers */
/* as above, but as bit values */
#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
@@ -130,6 +131,7 @@ static inline struct thread_info *curren
#define _TIF_FREEZE (1<<TIF_FREEZE)
#define _TIF_RUNLATCH (1<<TIF_RUNLATCH)
#define _TIF_ABI_PENDING (1<<TIF_ABI_PENDING)
+#define _TIF_DEBUG (1<<TIF_DEBUG)
#define _TIF_SYSCALL_T_OR_A (_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP)
#define _TIF_USER_WORK_MASK (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
^ permalink raw reply [flat|nested] 15+ messages in thread* [Patch 2/6] Introduce PPC64 specific Hardware Breakpoint interfaces
[not found] <20090726235854.574539012@prasadkr_t60p.in.ibm.com>
2009-07-27 0:12 ` [Patch 1/6] Prepare the PowerPC platform for HW Breakpoint infrastructure K.Prasad
@ 2009-07-27 0:13 ` K.Prasad
2009-07-31 6:16 ` David Gibson
2009-07-27 0:18 ` [Patch 3/6] Modify ptrace code to use " K.Prasad
` (3 subsequent siblings)
5 siblings, 1 reply; 15+ messages in thread
From: K.Prasad @ 2009-07-27 0:13 UTC (permalink / raw)
To: David Gibson, linuxppc-dev
Cc: Michael Neuling, Benjamin Herrenschmidt, paulus, Alan Stern,
K.Prasad, Roland McGrath
Introduce PPC64 implementation for the generic hardware breakpoint interfaces
defined in kernel/hw_breakpoint.c. Enable the HAVE_HW_BREAKPOINT flag and the
Makefile.
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
---
arch/powerpc/Kconfig | 1
arch/powerpc/kernel/Makefile | 2
arch/powerpc/kernel/hw_breakpoint.c | 298 ++++++++++++++++++++++++++++++++++++
arch/powerpc/kernel/ptrace.c | 4
4 files changed, 304 insertions(+), 1 deletion(-)
Index: linux-2.6-tip.hbkpt/arch/powerpc/Kconfig
===================================================================
--- linux-2.6-tip.hbkpt.orig/arch/powerpc/Kconfig
+++ linux-2.6-tip.hbkpt/arch/powerpc/Kconfig
@@ -126,6 +126,7 @@ config PPC
select HAVE_SYSCALL_WRAPPERS if PPC64
select GENERIC_ATOMIC64 if PPC32
select HAVE_PERF_COUNTERS
+ select HAVE_HW_BREAKPOINT if PPC64
config EARLY_PRINTK
bool
Index: linux-2.6-tip.hbkpt/arch/powerpc/kernel/Makefile
===================================================================
--- linux-2.6-tip.hbkpt.orig/arch/powerpc/kernel/Makefile
+++ linux-2.6-tip.hbkpt/arch/powerpc/kernel/Makefile
@@ -35,7 +35,7 @@ obj-$(CONFIG_PPC64) += setup_64.o sys_p
signal_64.o ptrace32.o \
paca.o cpu_setup_ppc970.o \
cpu_setup_pa6t.o \
- firmware.o nvram_64.o
+ firmware.o nvram_64.o hw_breakpoint.o
obj64-$(CONFIG_RELOCATABLE) += reloc_64.o
obj-$(CONFIG_PPC64) += vdso64/
obj-$(CONFIG_ALTIVEC) += vecemu.o
Index: linux-2.6-tip.hbkpt/arch/powerpc/kernel/hw_breakpoint.c
===================================================================
--- /dev/null
+++ linux-2.6-tip.hbkpt/arch/powerpc/kernel/hw_breakpoint.c
@@ -0,0 +1,298 @@
+/*
+ * HW_breakpoint: a unified kernel/user-space hardware breakpoint facility,
+ * using the CPU's debug registers.
+ */
+
+/*
+ * 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 of the License, 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright © 2009 IBM Corporation
+ */
+
+#include <linux/notifier.h>
+#include <linux/kallsyms.h>
+#include <linux/kprobes.h>
+#include <linux/percpu.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+
+#include <asm/hw_breakpoint.h>
+#include <asm/processor.h>
+#include <asm/sstep.h>
+
+/* Store the kernel-space breakpoint address value */
+static unsigned long kdabr;
+
+/*
+ * Temporarily stores address for DABR before it is written by the
+ * single-step handler routine
+ */
+static DEFINE_PER_CPU(unsigned long, dabr_data);
+
+void arch_update_kernel_hw_breakpoint(void *unused)
+{
+ struct hw_breakpoint *bp;
+
+ /* Check if there is nothing to update */
+ if (hbp_kernel_pos == HBP_NUM)
+ return;
+
+ per_cpu(this_hbp_kernel[hbp_kernel_pos], get_cpu()) = bp =
+ hbp_kernel[hbp_kernel_pos];
+ if (bp == NULL)
+ kdabr = 0;
+ else
+ kdabr = (bp->info.address & ~HW_BREAKPOINT_ALIGN) |
+ bp->info.type | DABR_TRANSLATION;
+ set_dabr(kdabr);
+ put_cpu();
+}
+
+/*
+ * Install the thread breakpoints in their debug registers.
+ */
+void arch_install_thread_hw_breakpoint(struct task_struct *tsk)
+{
+ set_dabr(tsk->thread.dabr);
+}
+
+/*
+ * Clear the DABR which contains the thread-specific breakpoint address
+ */
+void arch_uninstall_thread_hw_breakpoint()
+{
+ set_dabr(0);
+}
+
+/*
+ * Store a breakpoint's encoded address, length, and type.
+ */
+int arch_store_info(struct hw_breakpoint *bp, struct task_struct *tsk)
+{
+ /* Symbol names from user-space are rejected */
+ if (tsk) {
+ if (bp->info.name)
+ return -EINVAL;
+ else
+ return 0;
+ }
+ /*
+ * User-space requests will always have the address field populated
+ * For kernel-addresses, either the address or symbol name can be
+ * specified.
+ */
+ if (bp->info.name)
+ bp->info.address = (unsigned long)
+ kallsyms_lookup_name(bp->info.name);
+ if (bp->info.address)
+ if (kallsyms_lookup_size_offset(bp->info.address,
+ &(bp->info.symbolsize), NULL))
+ return 0;
+ return -EINVAL;
+}
+
+/*
+ * Validate the arch-specific HW Breakpoint register settings
+ */
+int arch_validate_hwbkpt_settings(struct hw_breakpoint *bp,
+ struct task_struct *tsk)
+{
+ int is_kernel, ret = -EINVAL;
+
+ if (!bp)
+ return ret;
+
+ switch (bp->info.type) {
+ case HW_BREAKPOINT_READ:
+ case HW_BREAKPOINT_WRITE:
+ case HW_BREAKPOINT_RW:
+ break;
+ default:
+ return ret;
+ }
+
+ if (!bp->triggered)
+ return -EINVAL;
+
+ ret = arch_store_info(bp, tsk);
+ is_kernel = is_kernel_addr(bp->info.address);
+ if ((tsk && is_kernel) || (!tsk && !is_kernel))
+ return -EINVAL;
+
+ return ret;
+}
+
+void arch_update_user_hw_breakpoint(int pos, struct task_struct *tsk)
+{
+ struct thread_struct *thread = &(tsk->thread);
+ struct hw_breakpoint *bp = thread->hbp[0];
+
+ if (bp)
+ thread->dabr = (bp->info.address & ~HW_BREAKPOINT_ALIGN) |
+ bp->info.type | DABR_TRANSLATION;
+ else
+ thread->dabr = 0;
+}
+
+void arch_flush_thread_hw_breakpoint(struct task_struct *tsk)
+{
+ struct thread_struct *thread = &(tsk->thread);
+
+ thread->dabr = 0;
+}
+
+/*
+ * Handle debug exception notifications.
+ */
+int __kprobes hw_breakpoint_handler(struct die_args *args)
+{
+ int rc = NOTIFY_STOP;
+ struct hw_breakpoint *bp;
+ struct pt_regs *regs = args->regs;
+ unsigned long dar = regs->dar;
+ int cpu, is_kernel, stepped = 1;
+
+ is_kernel = (hbp_kernel_pos == HBP_NUM) ? 0 : 1;
+
+ /* Disable breakpoints during exception handling */
+ set_dabr(0);
+
+ cpu = get_cpu();
+ /* Determine whether kernel- or user-space address is the trigger */
+ bp = is_kernel ?
+ per_cpu(this_hbp_kernel[0], cpu) : current->thread.hbp[0];
+ /*
+ * bp can be NULL due to lazy debug register switching
+ * or due to the delay between updates of hbp_kernel_pos
+ * and this_hbp_kernel.
+ */
+ if (!bp)
+ goto out;
+
+ per_cpu(dabr_data, cpu) = is_kernel ? kdabr : current->thread.dabr;
+
+ /* Verify if dar lies within the address range occupied by the symbol
+ * being watched. Since we cannot get the symbol size for
+ * user-space requests we skip this check in that case
+ */
+ if (is_kernel &&
+ !((bp->info.address <= dar) &&
+ (dar <= (bp->info.address + bp->info.symbolsize))))
+ /*
+ * This exception is triggered not because of a memory access on
+ * the monitored variable but in the double-word address range
+ * in which it is contained. We will consume this exception,
+ * considering it as 'noise'.
+ */
+ goto out;
+
+ (bp->triggered)(bp, regs);
+ /*
+ * Return early without restoring DABR if the breakpoint is from
+ * user-space which always operates in one-shot mode
+ */
+ if (!is_kernel) {
+ rc = NOTIFY_DONE;
+ goto out;
+ }
+
+ stepped = emulate_step(regs, regs->nip);
+ /*
+ * Single-step the causative instruction manually if
+ * emulate_step() could not execute it
+ */
+ if (stepped == 0) {
+ regs->msr |= MSR_SE;
+ goto out;
+ }
+ set_dabr(per_cpu(dabr_data, cpu));
+
+out:
+ /* Enable pre-emption only if single-stepping is finished */
+ if (stepped) {
+ per_cpu(dabr_data, cpu) = 0;
+ put_cpu();
+ }
+ return rc;
+}
+
+/*
+ * Handle single-step exceptions following a DABR hit.
+ */
+int __kprobes single_step_dabr_instruction(struct die_args *args)
+{
+ struct pt_regs *regs = args->regs;
+ int cpu = get_cpu();
+ int ret = NOTIFY_DONE;
+ siginfo_t info;
+ unsigned long this_dabr_data = per_cpu(dabr_data, cpu);
+
+ /*
+ * Check if we are single-stepping as a result of a
+ * previous HW Breakpoint exception
+ */
+ if (this_dabr_data == 0)
+ goto out;
+
+ regs->msr &= ~MSR_SE;
+ /* Deliver signal to user-space */
+ if (this_dabr_data < TASK_SIZE) {
+ info.si_signo = SIGTRAP;
+ info.si_errno = 0;
+ info.si_code = TRAP_HWBKPT;
+ info.si_addr = (void __user *)(per_cpu(dabr_data, cpu));
+ force_sig_info(SIGTRAP, &info, current);
+ }
+
+ set_dabr(this_dabr_data);
+ per_cpu(dabr_data, cpu) = 0;
+ ret = NOTIFY_STOP;
+ /*
+ * If single-stepped after hw_breakpoint_handler(), pre-emption is
+ * already disabled.
+ */
+ put_cpu();
+
+out:
+ /*
+ * A put_cpu() call is required to complement the get_cpu()
+ * call used initially
+ */
+ put_cpu();
+ return ret;
+}
+
+/*
+ * Handle debug exception notifications.
+ */
+int __kprobes hw_breakpoint_exceptions_notify(
+ struct notifier_block *unused, unsigned long val, void *data)
+{
+ int ret = NOTIFY_DONE;
+
+ switch (val) {
+ case DIE_DABR_MATCH:
+ ret = hw_breakpoint_handler(data);
+ break;
+ case DIE_SSTEP:
+ ret = single_step_dabr_instruction(data);
+ break;
+ }
+
+ return ret;
+}
Index: linux-2.6-tip.hbkpt/arch/powerpc/kernel/ptrace.c
===================================================================
--- linux-2.6-tip.hbkpt.orig/arch/powerpc/kernel/ptrace.c
+++ linux-2.6-tip.hbkpt/arch/powerpc/kernel/ptrace.c
@@ -755,6 +755,10 @@ void user_disable_single_step(struct tas
clear_tsk_thread_flag(task, TIF_SINGLESTEP);
}
+void ptrace_triggered(struct hw_breakpoint *bp, struct pt_regs *regs)
+{
+}
+
int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
unsigned long data)
{
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: [Patch 2/6] Introduce PPC64 specific Hardware Breakpoint interfaces
2009-07-27 0:13 ` [Patch 2/6] Introduce PPC64 specific Hardware Breakpoint interfaces K.Prasad
@ 2009-07-31 6:16 ` David Gibson
2009-08-03 20:59 ` K.Prasad
0 siblings, 1 reply; 15+ messages in thread
From: David Gibson @ 2009-07-31 6:16 UTC (permalink / raw)
To: K.Prasad
Cc: Michael Neuling, Benjamin Herrenschmidt, linuxppc-dev, paulus,
Alan Stern, Roland McGrath
On Mon, Jul 27, 2009 at 05:43:17AM +0530, K.Prasad wrote:
> Introduce PPC64 implementation for the generic hardware breakpoint interfaces
> defined in kernel/hw_breakpoint.c. Enable the HAVE_HW_BREAKPOINT flag and the
> Makefile.
[snip]
> +/*
> + * Handle debug exception notifications.
> + */
> +int __kprobes hw_breakpoint_handler(struct die_args *args)
> +{
> + int rc = NOTIFY_STOP;
> + struct hw_breakpoint *bp;
> + struct pt_regs *regs = args->regs;
> + unsigned long dar = regs->dar;
> + int cpu, is_kernel, stepped = 1;
> +
> + is_kernel = (hbp_kernel_pos == HBP_NUM) ? 0 : 1;
> +
> + /* Disable breakpoints during exception handling */
> + set_dabr(0);
> +
> + cpu = get_cpu();
> + /* Determine whether kernel- or user-space address is the trigger */
> + bp = is_kernel ?
> + per_cpu(this_hbp_kernel[0], cpu) : current->thread.hbp[0];
> + /*
> + * bp can be NULL due to lazy debug register switching
> + * or due to the delay between updates of hbp_kernel_pos
> + * and this_hbp_kernel.
> + */
> + if (!bp)
> + goto out;
> +
> + per_cpu(dabr_data, cpu) = is_kernel ? kdabr : current->thread.dabr;
> +
> + /* Verify if dar lies within the address range occupied by the symbol
> + * being watched. Since we cannot get the symbol size for
> + * user-space requests we skip this check in that case
> + */
> + if (is_kernel &&
> + !((bp->info.address <= dar) &&
> + (dar <= (bp->info.address + bp->info.symbolsize))))
> + /*
> + * This exception is triggered not because of a memory access on
> + * the monitored variable but in the double-word address range
> + * in which it is contained. We will consume this exception,
> + * considering it as 'noise'.
> + */
> + goto out;
> +
> + (bp->triggered)(bp, regs);
It bothers me that the trigger function is executed before the
trapping instruction, but the SIGTRAP occurs afterwards. Since
they're both responses to the trap, it seems logical to me that they
should occur at the same time (from the trapping program's point of
view, at least).
> + /*
> + * Return early without restoring DABR if the breakpoint is from
> + * user-space which always operates in one-shot mode
> + */
> + if (!is_kernel) {
> + rc = NOTIFY_DONE;
> + goto out;
> + }
> +
> + stepped = emulate_step(regs, regs->nip);
> + /*
> + * Single-step the causative instruction manually if
> + * emulate_step() could not execute it
> + */
> + if (stepped == 0) {
> + regs->msr |= MSR_SE;
> + goto out;
> + }
> + set_dabr(per_cpu(dabr_data, cpu));
> +
> +out:
> + /* Enable pre-emption only if single-stepping is finished */
> + if (stepped) {
> + per_cpu(dabr_data, cpu) = 0;
> + put_cpu();
> + }
> + return rc;
> +}
> +
> +/*
> + * Handle single-step exceptions following a DABR hit.
> + */
> +int __kprobes single_step_dabr_instruction(struct die_args *args)
> +{
> + struct pt_regs *regs = args->regs;
> + int cpu = get_cpu();
> + int ret = NOTIFY_DONE;
> + siginfo_t info;
> + unsigned long this_dabr_data = per_cpu(dabr_data, cpu);
> +
> + /*
> + * Check if we are single-stepping as a result of a
> + * previous HW Breakpoint exception
> + */
> + if (this_dabr_data == 0)
> + goto out;
> +
> + regs->msr &= ~MSR_SE;
> + /* Deliver signal to user-space */
> + if (this_dabr_data < TASK_SIZE) {
> + info.si_signo = SIGTRAP;
> + info.si_errno = 0;
> + info.si_code = TRAP_HWBKPT;
> + info.si_addr = (void __user *)(per_cpu(dabr_data, cpu));
> + force_sig_info(SIGTRAP, &info, current);
> + }
> +
> + set_dabr(this_dabr_data);
> + per_cpu(dabr_data, cpu) = 0;
> + ret = NOTIFY_STOP;
> + /*
> + * If single-stepped after hw_breakpoint_handler(), pre-emption is
> + * already disabled.
> + */
> + put_cpu();
> +
> +out:
> + /*
> + * A put_cpu() call is required to complement the get_cpu()
> + * call used initially
> + */
> + put_cpu();
> + return ret;
> +}
> +
> +/*
> + * Handle debug exception notifications.
> + */
> +int __kprobes hw_breakpoint_exceptions_notify(
Um.. there seems to be a pretty glaring problem here, in that AFAICT
in this revision of the series, this function is never invoked, and so
your breakpoint handling code will never be executed. i.e. the
changes to do_dabr to connect your code seem to be missing.
> + struct notifier_block *unused, unsigned long val, void *data)
> +{
> + int ret = NOTIFY_DONE;
> +
> + switch (val) {
> + case DIE_DABR_MATCH:
> + ret = hw_breakpoint_handler(data);
> + break;
> + case DIE_SSTEP:
> + ret = single_step_dabr_instruction(data);
> + break;
> + }
> +
> + return ret;
> +}
> Index: linux-2.6-tip.hbkpt/arch/powerpc/kernel/ptrace.c
> ===================================================================
> --- linux-2.6-tip.hbkpt.orig/arch/powerpc/kernel/ptrace.c
> +++ linux-2.6-tip.hbkpt/arch/powerpc/kernel/ptrace.c
> @@ -755,6 +755,10 @@ void user_disable_single_step(struct tas
> clear_tsk_thread_flag(task, TIF_SINGLESTEP);
> }
>
> +void ptrace_triggered(struct hw_breakpoint *bp, struct pt_regs *regs)
> +{
> +}
This is never used, so does not belong in this patch.
> int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
> unsigned long data)
> {
>
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: [Patch 2/6] Introduce PPC64 specific Hardware Breakpoint interfaces
2009-07-31 6:16 ` David Gibson
@ 2009-08-03 20:59 ` K.Prasad
2009-08-05 2:55 ` David Gibson
0 siblings, 1 reply; 15+ messages in thread
From: K.Prasad @ 2009-08-03 20:59 UTC (permalink / raw)
To: David Gibson
Cc: Michael Neuling, Benjamin Herrenschmidt, linuxppc-dev, paulus,
Alan Stern, Roland McGrath
On Fri, Jul 31, 2009 at 04:16:46PM +1000, David Gibson wrote:
> On Mon, Jul 27, 2009 at 05:43:17AM +0530, K.Prasad wrote:
> > Introduce PPC64 implementation for the generic hardware breakpoint interfaces
> > defined in kernel/hw_breakpoint.c. Enable the HAVE_HW_BREAKPOINT flag and the
> > Makefile.
>
> [snip]
> > +/*
> > + * Handle debug exception notifications.
> > + */
> > +int __kprobes hw_breakpoint_handler(struct die_args *args)
> > +{
> > + int rc = NOTIFY_STOP;
> > + struct hw_breakpoint *bp;
> > + struct pt_regs *regs = args->regs;
> > + unsigned long dar = regs->dar;
> > + int cpu, is_kernel, stepped = 1;
> > +
> > + is_kernel = (hbp_kernel_pos == HBP_NUM) ? 0 : 1;
> > +
> > + /* Disable breakpoints during exception handling */
> > + set_dabr(0);
> > +
> > + cpu = get_cpu();
> > + /* Determine whether kernel- or user-space address is the trigger */
> > + bp = is_kernel ?
> > + per_cpu(this_hbp_kernel[0], cpu) : current->thread.hbp[0];
> > + /*
> > + * bp can be NULL due to lazy debug register switching
> > + * or due to the delay between updates of hbp_kernel_pos
> > + * and this_hbp_kernel.
> > + */
> > + if (!bp)
> > + goto out;
> > +
> > + per_cpu(dabr_data, cpu) = is_kernel ? kdabr : current->thread.dabr;
> > +
> > + /* Verify if dar lies within the address range occupied by the symbol
> > + * being watched. Since we cannot get the symbol size for
> > + * user-space requests we skip this check in that case
> > + */
> > + if (is_kernel &&
> > + !((bp->info.address <= dar) &&
> > + (dar <= (bp->info.address + bp->info.symbolsize))))
> > + /*
> > + * This exception is triggered not because of a memory access on
> > + * the monitored variable but in the double-word address range
> > + * in which it is contained. We will consume this exception,
> > + * considering it as 'noise'.
> > + */
> > + goto out;
> > +
> > + (bp->triggered)(bp, regs);
>
> It bothers me that the trigger function is executed before the
> trapping instruction, but the SIGTRAP occurs afterwards. Since
> they're both responses to the trap, it seems logical to me that they
> should occur at the same time (from the trapping program's point of
> view, at least).
>
How about moving the triggered function to the single-step handler code
for both kernel- and user-space?
That would make it behave like a trigger-after-execute (and synchronised
with the signal-delivery timing).
> > + /*
> > + * Return early without restoring DABR if the breakpoint is from
> > + * user-space which always operates in one-shot mode
> > + */
> > + if (!is_kernel) {
> > + rc = NOTIFY_DONE;
> > + goto out;
> > + }
> > +
> > + stepped = emulate_step(regs, regs->nip);
> > + /*
> > + * Single-step the causative instruction manually if
> > + * emulate_step() could not execute it
> > + */
> > + if (stepped == 0) {
> > + regs->msr |= MSR_SE;
> > + goto out;
> > + }
> > + set_dabr(per_cpu(dabr_data, cpu));
> > +
> > +out:
> > + /* Enable pre-emption only if single-stepping is finished */
> > + if (stepped) {
> > + per_cpu(dabr_data, cpu) = 0;
> > + put_cpu();
> > + }
> > + return rc;
> > +}
> > +
> > +/*
> > + * Handle single-step exceptions following a DABR hit.
> > + */
> > +int __kprobes single_step_dabr_instruction(struct die_args *args)
> > +{
> > + struct pt_regs *regs = args->regs;
> > + int cpu = get_cpu();
> > + int ret = NOTIFY_DONE;
> > + siginfo_t info;
> > + unsigned long this_dabr_data = per_cpu(dabr_data, cpu);
> > +
> > + /*
> > + * Check if we are single-stepping as a result of a
> > + * previous HW Breakpoint exception
> > + */
> > + if (this_dabr_data == 0)
> > + goto out;
> > +
> > + regs->msr &= ~MSR_SE;
> > + /* Deliver signal to user-space */
> > + if (this_dabr_data < TASK_SIZE) {
> > + info.si_signo = SIGTRAP;
> > + info.si_errno = 0;
> > + info.si_code = TRAP_HWBKPT;
> > + info.si_addr = (void __user *)(per_cpu(dabr_data, cpu));
> > + force_sig_info(SIGTRAP, &info, current);
> > + }
> > +
> > + set_dabr(this_dabr_data);
> > + per_cpu(dabr_data, cpu) = 0;
> > + ret = NOTIFY_STOP;
> > + /*
> > + * If single-stepped after hw_breakpoint_handler(), pre-emption is
> > + * already disabled.
> > + */
> > + put_cpu();
> > +
> > +out:
> > + /*
> > + * A put_cpu() call is required to complement the get_cpu()
> > + * call used initially
> > + */
> > + put_cpu();
> > + return ret;
> > +}
> > +
> > +/*
> > + * Handle debug exception notifications.
> > + */
> > +int __kprobes hw_breakpoint_exceptions_notify(
>
> Um.. there seems to be a pretty glaring problem here, in that AFAICT
> in this revision of the series, this function is never invoked, and so
> your breakpoint handling code will never be executed. i.e. the
> changes to do_dabr to connect your code seem to be missing.
>
I realised it only after you pointed out...some remnants from the
previous version have caused it. While the patch should have treated
only ptrace in a special manner (one-shot), it erroneously does it for all
user-space. I will change it in the next version of the patchset.
Thanks,
K.Prasad
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: [Patch 2/6] Introduce PPC64 specific Hardware Breakpoint interfaces
2009-08-03 20:59 ` K.Prasad
@ 2009-08-05 2:55 ` David Gibson
0 siblings, 0 replies; 15+ messages in thread
From: David Gibson @ 2009-08-05 2:55 UTC (permalink / raw)
To: K.Prasad
Cc: Michael Neuling, Benjamin Herrenschmidt, linuxppc-dev, paulus,
Alan Stern, Roland McGrath
On Tue, Aug 04, 2009 at 02:29:38AM +0530, K.Prasad wrote:
> On Fri, Jul 31, 2009 at 04:16:46PM +1000, David Gibson wrote:
> > On Mon, Jul 27, 2009 at 05:43:17AM +0530, K.Prasad wrote:
[snip]
> > > + /* Verify if dar lies within the address range occupied by the symbol
> > > + * being watched. Since we cannot get the symbol size for
> > > + * user-space requests we skip this check in that case
> > > + */
> > > + if (is_kernel &&
> > > + !((bp->info.address <= dar) &&
> > > + (dar <= (bp->info.address + bp->info.symbolsize))))
> > > + /*
> > > + * This exception is triggered not because of a memory access on
> > > + * the monitored variable but in the double-word address range
> > > + * in which it is contained. We will consume this exception,
> > > + * considering it as 'noise'.
> > > + */
> > > + goto out;
> > > +
> > > + (bp->triggered)(bp, regs);
> >
> > It bothers me that the trigger function is executed before the
> > trapping instruction, but the SIGTRAP occurs afterwards. Since
> > they're both responses to the trap, it seems logical to me that they
> > should occur at the same time (from the trapping program's point of
> > view, at least).
> >
>
> How about moving the triggered function to the single-step handler code
> for both kernel- and user-space?
>
> That would make it behave like a trigger-after-execute (and synchronised
> with the signal-delivery timing).
I think that would be an improvement, yes. I definitely think the
SIGTRAP and the callback function should happen at the same time in
all cases. Possibly even have the callback function issue the SIGTRAP
rather than special casing that.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Patch 3/6] Modify ptrace code to use Hardware Breakpoint interfaces
[not found] <20090726235854.574539012@prasadkr_t60p.in.ibm.com>
2009-07-27 0:12 ` [Patch 1/6] Prepare the PowerPC platform for HW Breakpoint infrastructure K.Prasad
2009-07-27 0:13 ` [Patch 2/6] Introduce PPC64 specific Hardware Breakpoint interfaces K.Prasad
@ 2009-07-27 0:18 ` K.Prasad
2009-07-31 6:18 ` David Gibson
2009-07-27 0:18 ` [Patch 4/6] Modify process and processor handling code to recognise hardware debug registers K.Prasad
` (2 subsequent siblings)
5 siblings, 1 reply; 15+ messages in thread
From: K.Prasad @ 2009-07-27 0:18 UTC (permalink / raw)
To: David Gibson, linuxppc-dev
Cc: Michael Neuling, Benjamin Herrenschmidt, paulus, Alan Stern,
K.Prasad, Roland McGrath
Modify the ptrace code to use the hardware breakpoint interfaces for user-space.
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
---
arch/powerpc/kernel/ptrace.c | 43 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 43 insertions(+)
Index: linux-2.6-tip.hbkpt/arch/powerpc/kernel/ptrace.c
===================================================================
--- linux-2.6-tip.hbkpt.orig/arch/powerpc/kernel/ptrace.c
+++ linux-2.6-tip.hbkpt/arch/powerpc/kernel/ptrace.c
@@ -37,6 +37,7 @@
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/system.h>
+#include <asm/hw_breakpoint.h>
/*
* does not yet catch signals sent when the child dies.
@@ -757,11 +758,24 @@ void user_disable_single_step(struct tas
void ptrace_triggered(struct hw_breakpoint *bp, struct pt_regs *regs)
{
+ /*
+ * Unregister the breakpoint request here since ptrace has defined a
+ * one-shot behaviour for breakpoint exceptions in PPC64.
+ * The SIGTRAP signal is generated automatically for us in do_dabr().
+ * We don't have to do anything here
+ */
+ unregister_user_hw_breakpoint(current, bp);
+ kfree(bp);
}
int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
unsigned long data)
{
+#ifdef CONFIG_PPC64
+ struct thread_struct *thread = &(task->thread);
+ struct hw_breakpoint *bp;
+ int ret;
+#endif
/* For ppc64 we support one DABR and no IABR's at the moment (ppc64).
* For embedded processors we support one DAC and no IAC's at the
* moment.
@@ -791,6 +805,35 @@ int ptrace_set_debugreg(struct task_stru
if (data && !(data & DABR_TRANSLATION))
return -EIO;
+#ifdef CONFIG_PPC64
+ bp = thread->hbp[0];
+ if (data == 0) {
+ if (bp) {
+ unregister_user_hw_breakpoint(task, bp);
+ kfree(bp);
+ }
+ return 0;
+ }
+
+ if (bp) {
+ bp->info.type = data & HW_BREAKPOINT_RW;
+ task->thread.dabr = bp->info.address = data;
+ return modify_user_hw_breakpoint(task, bp);
+ }
+ bp = kzalloc(sizeof(struct hw_breakpoint), GFP_KERNEL);
+ if (!bp)
+ return -ENOMEM;
+
+ /* Store the type of breakpoint */
+ bp->info.type = data & HW_BREAKPOINT_RW;
+ bp->triggered = ptrace_triggered;
+ task->thread.dabr = bp->info.address = data;
+
+ ret = register_user_hw_breakpoint(task, bp);
+ if (ret)
+ return ret;
+#endif /* CONFIG_PPC64 */
+
/* Move contents to the DABR register */
task->thread.dabr = data;
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: [Patch 3/6] Modify ptrace code to use Hardware Breakpoint interfaces
2009-07-27 0:18 ` [Patch 3/6] Modify ptrace code to use " K.Prasad
@ 2009-07-31 6:18 ` David Gibson
0 siblings, 0 replies; 15+ messages in thread
From: David Gibson @ 2009-07-31 6:18 UTC (permalink / raw)
To: K.Prasad
Cc: Michael Neuling, Benjamin Herrenschmidt, linuxppc-dev, paulus,
Alan Stern, Roland McGrath
On Mon, Jul 27, 2009 at 05:48:27AM +0530, K.Prasad wrote:
> Modify the ptrace code to use the hardware breakpoint interfaces for user-space.
>
> Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
> ---
> arch/powerpc/kernel/ptrace.c | 43 +++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 43 insertions(+)
>
> Index: linux-2.6-tip.hbkpt/arch/powerpc/kernel/ptrace.c
> ===================================================================
> --- linux-2.6-tip.hbkpt.orig/arch/powerpc/kernel/ptrace.c
> +++ linux-2.6-tip.hbkpt/arch/powerpc/kernel/ptrace.c
> @@ -37,6 +37,7 @@
> #include <asm/page.h>
> #include <asm/pgtable.h>
> #include <asm/system.h>
> +#include <asm/hw_breakpoint.h>
>
> /*
> * does not yet catch signals sent when the child dies.
> @@ -757,11 +758,24 @@ void user_disable_single_step(struct tas
>
> void ptrace_triggered(struct hw_breakpoint *bp, struct pt_regs *regs)
> {
> + /*
> + * Unregister the breakpoint request here since ptrace has defined a
> + * one-shot behaviour for breakpoint exceptions in PPC64.
> + * The SIGTRAP signal is generated automatically for us in do_dabr().
> + * We don't have to do anything here
> + */
> + unregister_user_hw_breakpoint(current, bp);
> + kfree(bp);
This unregisters the breakpoint, but doesn't actually abort the
current breakpoint handling sequence it's invoked from. So, if your
breakpoint handler was invoked at all, which as previously mentioned,
I don't think it is, wouldn't this result in *two* SIGTRAPs from a
ptrace breakpoint: one issued before the trapping instruction from
do_dabr() and another afterwards from your step-over code.
> }
>
> int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
> unsigned long data)
> {
> +#ifdef CONFIG_PPC64
> + struct thread_struct *thread = &(task->thread);
> + struct hw_breakpoint *bp;
> + int ret;
> +#endif
> /* For ppc64 we support one DABR and no IABR's at the moment (ppc64).
> * For embedded processors we support one DAC and no IAC's at the
> * moment.
> @@ -791,6 +805,35 @@ int ptrace_set_debugreg(struct task_stru
> if (data && !(data & DABR_TRANSLATION))
> return -EIO;
>
> +#ifdef CONFIG_PPC64
> + bp = thread->hbp[0];
> + if (data == 0) {
> + if (bp) {
> + unregister_user_hw_breakpoint(task, bp);
> + kfree(bp);
> + }
> + return 0;
> + }
> +
> + if (bp) {
> + bp->info.type = data & HW_BREAKPOINT_RW;
> + task->thread.dabr = bp->info.address = data;
> + return modify_user_hw_breakpoint(task, bp);
> + }
> + bp = kzalloc(sizeof(struct hw_breakpoint), GFP_KERNEL);
> + if (!bp)
> + return -ENOMEM;
> +
> + /* Store the type of breakpoint */
> + bp->info.type = data & HW_BREAKPOINT_RW;
> + bp->triggered = ptrace_triggered;
> + task->thread.dabr = bp->info.address = data;
> +
> + ret = register_user_hw_breakpoint(task, bp);
> + if (ret)
> + return ret;
> +#endif /* CONFIG_PPC64 */
> +
> /* Move contents to the DABR register */
> task->thread.dabr = data;
>
>
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Patch 4/6] Modify process and processor handling code to recognise hardware debug registers
[not found] <20090726235854.574539012@prasadkr_t60p.in.ibm.com>
` (2 preceding siblings ...)
2009-07-27 0:18 ` [Patch 3/6] Modify ptrace code to use " K.Prasad
@ 2009-07-27 0:18 ` K.Prasad
2009-07-27 0:18 ` [Patch 5/6] Modify Data storage exception code to recognise DABR match first K.Prasad
2009-07-27 0:19 ` [Patch 6/6] Adapt kexec and samples code to recognise PPC64 hardware breakpoint usage K.Prasad
5 siblings, 0 replies; 15+ messages in thread
From: K.Prasad @ 2009-07-27 0:18 UTC (permalink / raw)
To: David Gibson, linuxppc-dev
Cc: Michael Neuling, Benjamin Herrenschmidt, paulus, Alan Stern,
K.Prasad, Roland McGrath
Modify process handling code to recognise hardware debug registers during copy
and flush operations. Introduce a new TIF_DEBUG task flag to indicate a
process's use of debug register. Load the debug register values into a
new CPU during initialisation.
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
---
arch/powerpc/kernel/process.c | 15 +++++++++++++++
arch/powerpc/kernel/smp.c | 2 ++
2 files changed, 17 insertions(+)
Index: linux-2.6-tip.hbkpt/arch/powerpc/kernel/process.c
===================================================================
--- linux-2.6-tip.hbkpt.orig/arch/powerpc/kernel/process.c
+++ linux-2.6-tip.hbkpt/arch/powerpc/kernel/process.c
@@ -50,6 +50,7 @@
#include <asm/syscalls.h>
#ifdef CONFIG_PPC64
#include <asm/firmware.h>
+#include <asm/hw_breakpoint.h>
#endif
#include <linux/kprobes.h>
#include <linux/kdebug.h>
@@ -254,8 +255,10 @@ void do_dabr(struct pt_regs *regs, unsig
11, SIGSEGV) == NOTIFY_STOP)
return;
+#ifndef CONFIG_PPC64
if (debugger_dabr_match(regs))
return;
+#endif
/* Clear the DAC and struct entries. One shot trigger */
#if defined(CONFIG_BOOKE)
@@ -372,8 +375,13 @@ struct task_struct *__switch_to(struct t
#endif /* CONFIG_SMP */
+#ifdef CONFIG_PPC64
+ if (unlikely(test_tsk_thread_flag(new, TIF_DEBUG)))
+ arch_install_thread_hw_breakpoint(new);
+#else
if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr))
set_dabr(new->thread.dabr);
+#endif /* CONFIG_PPC64 */
#if defined(CONFIG_BOOKE)
/* If new thread DAC (HW breakpoint) is the same then leave it */
@@ -550,6 +558,10 @@ void show_regs(struct pt_regs * regs)
void exit_thread(void)
{
discard_lazy_cpu_state();
+#ifdef CONFIG_PPC64
+ if (unlikely(test_tsk_thread_flag(current, TIF_DEBUG)))
+ flush_thread_hw_breakpoint(current);
+#endif /* CONFIG_PPC64 */
}
void flush_thread(void)
@@ -672,6 +684,9 @@ int copy_thread(unsigned long clone_flag
* function.
*/
kregs->nip = *((unsigned long *)ret_from_fork);
+
+ if (unlikely(test_tsk_thread_flag(current, TIF_DEBUG)))
+ copy_thread_hw_breakpoint(current, p, clone_flags);
#else
kregs->nip = (unsigned long)ret_from_fork;
#endif
Index: linux-2.6-tip.hbkpt/arch/powerpc/kernel/smp.c
===================================================================
--- linux-2.6-tip.hbkpt.orig/arch/powerpc/kernel/smp.c
+++ linux-2.6-tip.hbkpt/arch/powerpc/kernel/smp.c
@@ -48,6 +48,7 @@
#include <asm/vdso_datapage.h>
#ifdef CONFIG_PPC64
#include <asm/paca.h>
+#include <asm/hw_breakpoint.h>
#endif
#ifdef DEBUG
@@ -537,6 +538,7 @@ int __devinit start_secondary(void *unus
local_irq_enable();
+ load_debug_registers();
cpu_idle();
return 0;
}
^ permalink raw reply [flat|nested] 15+ messages in thread* [Patch 5/6] Modify Data storage exception code to recognise DABR match first
[not found] <20090726235854.574539012@prasadkr_t60p.in.ibm.com>
` (3 preceding siblings ...)
2009-07-27 0:18 ` [Patch 4/6] Modify process and processor handling code to recognise hardware debug registers K.Prasad
@ 2009-07-27 0:18 ` K.Prasad
2009-07-27 0:19 ` [Patch 6/6] Adapt kexec and samples code to recognise PPC64 hardware breakpoint usage K.Prasad
5 siblings, 0 replies; 15+ messages in thread
From: K.Prasad @ 2009-07-27 0:18 UTC (permalink / raw)
To: David Gibson, linuxppc-dev
Cc: Michael Neuling, Benjamin Herrenschmidt, paulus, Alan Stern,
K.Prasad, Roland McGrath
Modify Data storage exception code to first lookout for a DABR match before
recognising a kprobe or xmon exception.
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
---
arch/powerpc/mm/fault.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)
Index: linux-2.6-tip.hbkpt/arch/powerpc/mm/fault.c
===================================================================
--- linux-2.6-tip.hbkpt.orig/arch/powerpc/mm/fault.c
+++ linux-2.6-tip.hbkpt/arch/powerpc/mm/fault.c
@@ -137,6 +137,12 @@ int __kprobes do_page_fault(struct pt_re
error_code &= 0x48200000;
else
is_write = error_code & DSISR_ISSTORE;
+
+ if (error_code & DSISR_DABRMATCH) {
+ /* DABR match */
+ do_dabr(regs, address, error_code);
+ return 0;
+ }
#else
is_write = error_code & ESR_DST;
#endif /* CONFIG_4xx || CONFIG_BOOKE */
@@ -151,14 +157,6 @@ int __kprobes do_page_fault(struct pt_re
if (!user_mode(regs) && (address >= TASK_SIZE))
return SIGSEGV;
-#if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE))
- if (error_code & DSISR_DABRMATCH) {
- /* DABR match */
- do_dabr(regs, address, error_code);
- return 0;
- }
-#endif /* !(CONFIG_4xx || CONFIG_BOOKE)*/
-
if (in_atomic() || mm == NULL) {
if (!user_mode(regs))
return SIGSEGV;
^ permalink raw reply [flat|nested] 15+ messages in thread* [Patch 6/6] Adapt kexec and samples code to recognise PPC64 hardware breakpoint usage
[not found] <20090726235854.574539012@prasadkr_t60p.in.ibm.com>
` (4 preceding siblings ...)
2009-07-27 0:18 ` [Patch 5/6] Modify Data storage exception code to recognise DABR match first K.Prasad
@ 2009-07-27 0:19 ` K.Prasad
5 siblings, 0 replies; 15+ messages in thread
From: K.Prasad @ 2009-07-27 0:19 UTC (permalink / raw)
To: David Gibson, linuxppc-dev
Cc: Michael Neuling, Benjamin Herrenschmidt, paulus, Alan Stern,
K.Prasad, Roland McGrath
Modify kexec code to disable DABR registers before a reboot. Adapt the samples
code to populate PPC64-arch specific fields.
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
---
arch/powerpc/kernel/machine_kexec_64.c | 3 +++
samples/hw_breakpoint/data_breakpoint.c | 4 ++++
2 files changed, 7 insertions(+)
Index: linux-2.6-tip.hbkpt/arch/powerpc/kernel/machine_kexec_64.c
===================================================================
--- linux-2.6-tip.hbkpt.orig/arch/powerpc/kernel/machine_kexec_64.c
+++ linux-2.6-tip.hbkpt/arch/powerpc/kernel/machine_kexec_64.c
@@ -24,6 +24,7 @@
#include <asm/sections.h> /* _end */
#include <asm/prom.h>
#include <asm/smp.h>
+#include <asm/hw_breakpoint.h>
int default_machine_kexec_prepare(struct kimage *image)
{
@@ -214,6 +215,7 @@ static void kexec_prepare_cpus(void)
put_cpu();
local_irq_disable();
+ hw_breakpoint_disable();
}
#else /* ! SMP */
@@ -233,6 +235,7 @@ static void kexec_prepare_cpus(void)
if (ppc_md.kexec_cpu_down)
ppc_md.kexec_cpu_down(0, 0);
local_irq_disable();
+ hw_breakpoint_disable();
}
#endif /* SMP */
Index: linux-2.6-tip.hbkpt/samples/hw_breakpoint/data_breakpoint.c
===================================================================
--- linux-2.6-tip.hbkpt.orig/samples/hw_breakpoint/data_breakpoint.c
+++ linux-2.6-tip.hbkpt/samples/hw_breakpoint/data_breakpoint.c
@@ -54,6 +54,10 @@ static int __init hw_break_module_init(v
sample_hbp.info.type = HW_BREAKPOINT_WRITE;
sample_hbp.info.len = HW_BREAKPOINT_LEN_4;
#endif /* CONFIG_X86 */
+#ifdef CONFIG_PPC64
+ sample_hbp.info.name = ksym_name;
+ sample_hbp.info.type = HW_BREAKPOINT_WRITE;
+#endif /* CONFIG_PPC64 */
sample_hbp.triggered = (void *)sample_hbp_handler;
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