Merge branch 'linus' into perf/urgent

Merge reason: we need to fix a non-trivial merge conflict.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 33 insertions, 0 deletions

diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index 0d7c08784ef..3f88a45e6f0 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -41,6 +41,7 @@
 #include <linux/delay.h>
 #include <linux/sched.h>
 #include <linux/sysrq.h>
+#include <linux/reboot.h>
 #include <linux/init.h>
 #include <linux/kgdb.h>
 #include <linux/kdb.h>
@@ -75,6 +76,8 @@ static int			exception_level;
 struct kgdb_io          *dbg_io_ops;
 static DEFINE_SPINLOCK(kgdb_registration_lock);
 
+/* Action for the reboot notifiter, a global allow kdb to change it */
+static int kgdbreboot;
 /* kgdb console driver is loaded */
 static int kgdb_con_registered;
 /* determine if kgdb console output should be used */
@@ -96,6 +99,7 @@ static int __init opt_kgdb_con(char *str)
 early_param("kgdbcon", opt_kgdb_con);
 
 module_param(kgdb_use_con, int, 0644);
+module_param(kgdbreboot, int, 0644);
 
 /*
  * Holds information about breakpoints in a kernel. These breakpoints are
@@ -784,6 +788,33 @@ void __init dbg_late_init(void)
         kdb_init(KDB_INIT_FULL);
 }
 
+static int
+dbg_notify_reboot(struct notifier_block *this, unsigned long code, void *x)
+{
+        /*
+         * Take the following action on reboot notify depending on value:
+         *    1 == Enter debugger
+         *    0 == [the default] detatch debug client
+         *   -1 == Do nothing... and use this until the board resets
+         */
+        switch (kgdbreboot) {
+        case 1:
+                kgdb_breakpoint();
+        case -1:
+                goto done;
+        }
+        if (!dbg_kdb_mode)
+                gdbstub_exit(code);
+done:
+        return NOTIFY_DONE;
+}
+
+static struct notifier_block dbg_reboot_notifier = {
+        .notifier_call          = dbg_notify_reboot,
+        .next                   = NULL,
+        .priority               = INT_MAX,
+};
+
 static void kgdb_register_callbacks(void)
 {
         if (!kgdb_io_module_registered) {
@@ -791,6 +822,7 @@ static void kgdb_register_callbacks(void)
                 kgdb_arch_init();
                 if (!dbg_is_early)
                         kgdb_arch_late();
+                register_reboot_notifier(&dbg_reboot_notifier);
                 atomic_notifier_chain_register(&panic_notifier_list,
                                                &kgdb_panic_event_nb);
 #ifdef CONFIG_MAGIC_SYSRQ
@@ -812,6 +844,7 @@ static void kgdb_unregister_callbacks(void)
          */
         if (kgdb_io_module_registered) {
                 kgdb_io_module_registered = 0;
+                unregister_reboot_notifier(&dbg_reboot_notifier);
                 atomic_notifier_chain_unregister(&panic_notifier_list,
                                                &kgdb_panic_event_nb);
                 kgdb_arch_exit();