Per the kernel.org up merge, it has been requested to remove the
DIE_PAGE_FAULT because the notify chain kgdb attaches to does not
receive this, and also to reorganize the kgdb_notify() routine to be
cleaner. Run time testing of all the edge cases shows there is no
difference with this implementation vs the prior implementation.
Jason.
Signed-off-by: Jason Wessel <[EMAIL PROTECTED]>
---
arch/i386/kernel/kgdb.c | 71
++++++++++++++++++++++++++++------------------
arch/x86_64/kernel/kgdb.c | 68
++++++++++++++++++++++++++++----------------
include/asm-mips/kdebug.h | 1
3 files changed, 88 insertions(+), 52 deletions(-)
Index: linux-2.6.21-standard/arch/i386/kernel/kgdb.c
===================================================================
--- linux-2.6.21-standard.orig/arch/i386/kernel/kgdb.c
+++ linux-2.6.21-standard/arch/i386/kernel/kgdb.c
@@ -303,41 +303,58 @@ int kgdb_arch_handle_exception(int e_vec
return -1;
}
-/* Register KGDB with the i386die_chain so that we hook into all of the
right
- * spots. */
+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;
- /* Bad memory access? */
- if (cmd == DIE_PAGE_FAULT_NO_CONTEXT && atomic_read(&debugger_active)
- && kgdb_may_fault) {
- kgdb_fault_longjmp(kgdb_fault_jmp_regs);
- return NOTIFY_STOP;
- } else if (cmd == DIE_PAGE_FAULT)
- /* A normal page fault, ignore. */
+ switch (cmd) {
+ case DIE_NMI:
+ case DIE_NMI_IPI:
+ if (atomic_read(&debugger_active)) {
+ /* KGDB CPU roundup */
+ kgdb_nmihook(raw_smp_processor_id(), regs);
+ return NOTIFY_STOP;
+ }
return NOTIFY_DONE;
- else if ((cmd == DIE_NMI || cmd == DIE_NMI_IPI ||
- cmd == DIE_NMIWATCHDOG) && atomic_read(&debugger_active)) {
- /* CPU roundup */
- kgdb_nmihook(raw_smp_processor_id(), regs);
- return NOTIFY_STOP;
- } else if (cmd == DIE_DEBUG
- && atomic_read(&cpu_doing_single_step) ==
raw_smp_processor_id()
- && user_mode(regs)) {
- /* 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);
+ case DIE_NMIWATCHDOG:
+ if (atomic_read(&debugger_active)) {
+ /* KGDB CPU roundup */
+ kgdb_nmihook(raw_smp_processor_id(), regs);
+ return NOTIFY_STOP;
+ }
+ /* Enter debugger */
+ break;
+ case DIE_DEBUG:
+ if (atomic_read(&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_may_fault) {
+ kgdb_fault_longjmp(kgdb_fault_jmp_regs);
return NOTIFY_STOP;
- } else if (cmd == DIE_NMI_IPI || cmd == DIE_NMI || user_mode(regs) ||
- (cmd == DIE_DEBUG && atomic_read(&debugger_active)))
- /* Normal watchdog event or userspace debugging, or spurious
- * debug exception, ignore. */
- return NOTIFY_DONE;
+ }
if (kgdb_handle_exception(args->trapnr, args->signr,
args->err, regs))
Index: linux-2.6.21-standard/arch/x86_64/kernel/kgdb.c
===================================================================
--- linux-2.6.21-standard.orig/arch/x86_64/kernel/kgdb.c
+++ linux-2.6.21-standard/arch/x86_64/kernel/kgdb.c
@@ -379,38 +379,58 @@ 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 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;
- if (cmd == DIE_PAGE_FAULT_NO_CONTEXT && atomic_read(&debugger_active)
- && kgdb_may_fault) {
+ switch (cmd) {
+ case DIE_NMI:
+ case DIE_NMI_IPI:
+ if (atomic_read(&debugger_active)) {
+ /* KGDB CPU roundup */
+ kgdb_nmihook(raw_smp_processor_id(), regs);
+ return NOTIFY_STOP;
+ }
+ return NOTIFY_DONE;
+ case DIE_NMIWATCHDOG:
+ if (atomic_read(&debugger_active)) {
+ /* KGDB CPU roundup */
+ kgdb_nmihook(raw_smp_processor_id(), regs);
+ return NOTIFY_STOP;
+ }
+ /* Enter debugger */
+ break;
+ case DIE_DEBUG:
+ if (atomic_read(&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_may_fault) {
kgdb_fault_longjmp(kgdb_fault_jmp_regs);
return NOTIFY_STOP;
- /* CPU roundup? */
- } else if (atomic_read(&debugger_active) && cmd == DIE_NMI_IPI) {
- kgdb_nmihook(raw_smp_processor_id(), regs);
- return NOTIFY_STOP;
- /* See if KGDB is interested. */
- } else if (cmd == DIE_DEBUG
- && atomic_read(&cpu_doing_single_step) ==
raw_smp_processor_id()
- && user_mode(regs)) {
- /* 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;
- } else if (cmd == DIE_PAGE_FAULT || user_mode(regs) ||
- cmd == DIE_NMI_IPI || (cmd == DIE_DEBUG &&
- atomic_read(&debugger_active)))
- /* Userpace events, normal watchdog event, or spurious
- * debug exception. Ignore. */
- return NOTIFY_DONE;
+ }
if (kgdb_handle_exception(args->trapnr, args->signr,
args->err, regs))
Index: linux-2.6.21-standard/include/asm-mips/kdebug.h
===================================================================
--- linux-2.6.21-standard.orig/include/asm-mips/kdebug.h
+++ linux-2.6.21-standard/include/asm-mips/kdebug.h
@@ -30,7 +30,6 @@ enum die_val {
DIE_DIE,
DIE_KERNELDEBUG,
DIE_TRAP,
- DIE_PAGE_FAULT,
};
/*
-------------------------------------------------------------------------
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