[KGDB PATCH][4/7] Fix x86_64 hooks

Tom Rini
2004-02-27T21:43:02Z

Hello. The following is more complicated than it looks. This makes the
x86_64 stub add kgdb to the die_chain, and then remove all of the now
unneeded CHK_DEBUGGER statements, and other whitespace changes. In the end,
the x86_64 patch looks like:
arch/x86_64/Kconfig | 4
arch/x86_64/kernel/Makefile | 1
arch/x86_64/kernel/entry.S | 41 +++
arch/x86_64/kernel/irq.c | 2
arch/x86_64/kernel/kgdb.c | 478 +++++++++++++++++++++++++++++++++++++++++
arch/x86_64/kernel/traps.c | 3
include/asm-x86_64/kgdb.h | 54 ++++
include/asm-x86_64/processor.h | 1
8 files changed, 577 insertions(+), 7 deletions(-)

As an aside, I now know how to kill off user_schedule bits on i386/x86_64, so
with more thought on how to do it cleanly for everyone, the entry.S changes
can die.

diff -zrupN linux-2.6.3+config+serial/arch/x86_64/kernel/kgdb.c linux-2.6.3+config+serial+sysrq+arch_hooks/arch/x86_64/kernel/kgdb.c
--- linux-2.6.3+config+serial/arch/x86_64/kernel/kgdb.c 2004-02-27 12:16:13.000000000 -0700
+++ linux-2.6.3+config+serial+sysrq+arch_hooks/arch/x86_64/kernel/kgdb.c 2004-02-27 12:16:14.000000000 -0700
@@ -41,6 +41,7 @@
#endif
#include <linux/init.h>
#include <linux/debugger.h>
+#include <asm/kdebug.h>

/* Put the error code here just in case the user cares. */
int gdb_x86_64errcode;
@@ -443,6 +444,33 @@ struct pt_regs *kgdb_shadow_regs(struct
return NULL;
}

+/* Register KGDB with the die_chain so that we hook into all of the right
+ * spots. */
+static int kgdb_notify(struct notifier_block *self, unsigned long cmd,
+ void *ptr)
+{
+ struct die_args *d = ptr;
+
+ if (!kgdb_connected || (cmd == DIE_DEBUG && user_mode(d->regs)))
+ return NOTIFY_DONE;
+ if (cmd == DIE_NMI_IPI) {
+ if (atomic_read(debugger_active))
+ return NOTIFY_BAD;
+ } else if ((*linux_debug_hook)(d->trapnr, d->signr, d->err, d->regs))
+ return NOTIFY_BAD; /* skip */
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block kgdb_notifier = {
+ .notifier_call = kgdb_notify,
+};
+
+int kgdb_arch_init(void)
+{
+ notifier_chain_register(&die_chain, &kgdb_notifier);
+}
+
struct kgdb_arch arch_kgdb_ops = {
.gdb_bpt_instr = {0xcc},
.flags = KGDB_HW_BREAKPOINT,
diff -zrupN linux-2.6.3+config+serial/arch/x86_64/kernel/nmi.c linux-2.6.3+config+serial+sysrq+arch_hooks/arch/x86_64/kernel/nmi.c
--- linux-2.6.3+config+serial/arch/x86_64/kernel/nmi.c 2004-02-27 12:16:13.000000000 -0700
+++ linux-2.6.3+config+serial+sysrq+arch_hooks/arch/x86_64/kernel/nmi.c 2004-02-27 12:11:20.000000000 -0700
@@ -24,7 +24,6 @@
#include <linux/module.h>
#include <linux/sysdev.h>
#include <linux/nmi.h>
-#include <linux/debugger.h>

#include <asm/smp.h>
#include <asm/mtrr.h>
@@ -318,26 +317,13 @@ void nmi_watchdog_tick (struct pt_regs *
return;

sum = read_pda(apic_timer_irqs);
- if (atomic_read(&debugger_active)) {
-
- /*
- * The machine is in debugger, hold this cpu if already
- * not held.
- */
- debugger_nmihook(cpu, regs);
- alert_counter[cpu] = 0;
-
- } else if (last_irq_sums[cpu] == sum) {
-
+ if (last_irq_sums[cpu] == sum) {
/*
* Ayiee, looks like this CPU is stuck ...
* wait a few IRQs (5 seconds) before doing the oops ...
*/
alert_counter[cpu]++;
if (alert_counter[cpu] == 5*nmi_hz) {
-
- CHK_DEBUGGER(2,SIGSEGV,0,regs,)
-
if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_BAD) {
alert_counter[cpu] = 0;
return;
diff -zrupN linux-2.6.3+config+serial/arch/x86_64/kernel/traps.c linux-2.6.3+config+serial+sysrq+arch_hooks/arch/x86_64/kernel/traps.c
--- linux-2.6.3+config+serial/arch/x86_64/kernel/traps.c 2004-02-27 12:16:13.000000000 -0700
+++ linux-2.6.3+config+serial+sysrq+arch_hooks/arch/x86_64/kernel/traps.c 2004-02-27 12:16:14.000000000 -0700
@@ -364,7 +364,6 @@ void __die(const char * str, struct pt_r

void die(const char * str, struct pt_regs * regs, long err)
{
- CHK_DEBUGGER(1,SIGTRAP,err,regs,)
oops_begin();
handle_BUG(regs);
__die(str, regs, err);
@@ -438,7 +437,6 @@ static void do_trap(int trapnr, int sign
#define DO_ERROR(trapnr, signr, str, name) \
asmlinkage void do_##name(struct pt_regs * regs, long error_code) \
{ \
- CHK_DEBUGGER(1,SIGTRAP,error_code,regs,return) \
if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) == NOTIFY_BAD) \
return; \
do_trap(trapnr, signr, str, regs, error_code, NULL); \
@@ -646,7 +644,6 @@ asmlinkage void do_debug(struct pt_regs
force_sig_info(SIGTRAP, &info, tsk);
clear_dr7:
asm volatile("movq %0,%%db7"::"r"(0UL));
- CHK_DEBUGGER(1,SIGTRAP,error_code,regs,return)
notify_die(DIE_DEBUG, "debug", regs, error_code, 1, SIGTRAP);
return;

diff -zrupN linux-2.6.3+config+serial/arch/x86_64/mm/fault.c linux-2.6.3+config+serial+sysrq+arch_hooks/arch/x86_64/mm/fault.c
--- linux-2.6.3+config+serial/arch/x86_64/mm/fault.c 2004-02-27 12:16:13.000000000 -0700
+++ linux-2.6.3+config+serial+sysrq+arch_hooks/arch/x86_64/mm/fault.c 2004-02-27 12:10:49.000000000 -0700
@@ -23,7 +23,6 @@
#include <linux/vt_kern.h> /* For unblank_screen() */
#include <linux/compiler.h>
#include <linux/module.h>
-#include <linux/debugger.h>

#include <asm/system.h>
#include <asm/uaccess.h>
@@ -408,7 +407,6 @@ no_context:

if (is_prefetch(regs, address))
return;
- CHK_DEBUGGER(14, SIGSEGV,error_code, regs,)

if (is_errata93(regs, address))
return;
diff -zrupN linux-2.6.3+config+serial/include/asm-x86_64/calling.h linux-2.6.3+config+serial+sysrq+arch_hooks/include/asm-x86_64/calling.h
--- linux-2.6.3+config+serial/include/asm-x86_64/calling.h 2004-02-27 12:16:13.000000000 -0700
+++ linux-2.6.3+config+serial+sysrq+arch_hooks/include/asm-x86_64/calling.h 2004-02-27 12:12:03.000000000 -0700
@@ -12,7 +12,7 @@
#define RBX 40
/* arguments: interrupts/non tracing syscalls only save upto here*/
#define R11 48
-#define R10 56
+#define R10 56
#define R9 64
#define R8 72
#define RAX 80

--
Tom Rini