arm,kgdb: Add ability to trap into debugger on notify_die

Now that ARM implements the notify die handlers, add the ability for
the kernel debugger to receive the notifications.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: linux-arm-kernel@lists.infradead.org

1 files changed, 34 insertions, 0 deletions

diff --git a/arch/arm/kernel/kgdb.c b/arch/arm/kernel/kgdb.c
index cf846cade354..778c2f7024ff 100644
--- a/arch/arm/kernel/kgdb.c
+++ b/arch/arm/kernel/kgdb.c
@@ -10,6 +10,7 @@
  *           Deepak Saxena <dsaxena@plexity.net>
  */
 #include <linux/irq.h>
+#include <linux/kdebug.h>
 #include <linux/kgdb.h>
 #include <asm/traps.h>
 
@@ -180,6 +181,33 @@ void kgdb_roundup_cpus(unsigned long flags)
        local_irq_disable();
 }
 
+static int __kgdb_notify(struct die_args *args, unsigned long cmd)
+{
+        struct pt_regs *regs = args->regs;
+
+        if (kgdb_handle_exception(1, args->signr, cmd, 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,
+        .priority       = -INT_MAX,
+};
+
+
 /**
  *      kgdb_arch_init - Perform any architecture specific initalization.
  *
@@ -188,6 +216,11 @@ void kgdb_roundup_cpus(unsigned long flags)
  */
 int kgdb_arch_init(void)
 {
+        int ret = register_die_notifier(&kgdb_notifier);
+
+        if (ret != 0)
+                return ret;
+
         register_undef_hook(&kgdb_brkpt_hook);
         register_undef_hook(&kgdb_compiled_brkpt_hook);
 
@@ -204,6 +237,7 @@ void kgdb_arch_exit(void)
 {
         unregister_undef_hook(&kgdb_brkpt_hook);
         unregister_undef_hook(&kgdb_compiled_brkpt_hook);
+        unregister_die_notifier(&kgdb_notifier);
 }
 
 /*