kgdb: clocksource watchdog

In order to not trip the clocksource watchdog, kgdb must touch the
clocksource watchdog on the return to normal system run state.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

3 files changed, 17 insertions, 0 deletions

diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index 85778a4b1209..35094479ca55 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -216,6 +216,7 @@ static inline void clocksource_calculate_interval(struct clocksource *c,
 /* used to install a new clocksource */
 extern int clocksource_register(struct clocksource*);
 extern void clocksource_unregister(struct clocksource*);
+extern void clocksource_touch_watchdog(void);
 extern struct clocksource* clocksource_get_next(void);
 extern void clocksource_change_rating(struct clocksource *cs, int rating);
 extern void clocksource_resume(void);
diff --git a/kernel/kgdb.c b/kernel/kgdb.c
index 017ee782bc08..e3f603740425 100644
--- a/kernel/kgdb.c
+++ b/kernel/kgdb.c
@@ -28,6 +28,7 @@
  * kind, whether express or implied.
  */
 #include <linux/pid_namespace.h>
+#include <linux/clocksource.h>
 #include <linux/interrupt.h>
 #include <linux/spinlock.h>
 #include <linux/console.h>
@@ -574,6 +575,7 @@ static void kgdb_wait(struct pt_regs *regs)
 
         /* Signal the primary CPU that we are done: */
         atomic_set(&cpu_in_kgdb[cpu], 0);
+        clocksource_touch_watchdog();
         local_irq_restore(flags);
 }
 #endif
@@ -1396,6 +1398,7 @@ acquirelock:
             atomic_read(&kgdb_cpu_doing_single_step) != cpu) {
 
                 atomic_set(&kgdb_active, -1);
+                clocksource_touch_watchdog();
                 local_irq_restore(flags);
 
                 goto acquirelock;
@@ -1487,6 +1490,7 @@ acquirelock:
 kgdb_restore:
         /* Free kgdb_active */
         atomic_set(&kgdb_active, -1);
+        clocksource_touch_watchdog();
         local_irq_restore(flags);
 
         return error;
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 7f60097d443a..f61402b1f2d0 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -222,6 +222,18 @@ void clocksource_resume(void)
 }
 
 /**
+ * clocksource_touch_watchdog - Update watchdog
+ *
+ * Update the watchdog after exception contexts such as kgdb so as not
+ * to incorrectly trip the watchdog.
+ *
+ */
+void clocksource_touch_watchdog(void)
+{
+        clocksource_resume_watchdog();
+}
+
+/**
  * clocksource_get_next - Returns the selected clocksource
  *
  */