6 files changed, 57 insertions, 29 deletions

diff --git a/arch/i386/kernel/nmi.c b/arch/i386/kernel/nmi.c
index d88004343034..bd96ea4f2942 100644
--- a/arch/i386/kernel/nmi.c
+++ b/arch/i386/kernel/nmi.c
@@ -781,7 +781,7 @@ EXPORT_SYMBOL(touch_nmi_watchdog);
 
 extern void die_nmi(struct pt_regs *, const char *msg);
 
-void nmi_watchdog_tick (struct pt_regs * regs, unsigned reason)
+int nmi_watchdog_tick (struct pt_regs * regs, unsigned reason)
 {
 
         /*
@@ -794,10 +794,12 @@ void nmi_watchdog_tick (struct pt_regs * regs, unsigned reason)
         int cpu = smp_processor_id();
         struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);
         u64 dummy;
+        int rc=0;
 
         /* check for other users first */
         if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
                         == NOTIFY_STOP) {
+                rc = 1;
                 touched = 1;
         }
 
@@ -850,10 +852,18 @@ void nmi_watchdog_tick (struct pt_regs * regs, unsigned reason)
                         }
                         /* start the cycle over again */
                         write_watchdog_counter(wd->perfctr_msr, NULL);
-                }
+                        rc = 1;
+                } else if (nmi_watchdog == NMI_IO_APIC) {
+                        /* don't know how to accurately check for this.
+                         * just assume it was a watchdog timer interrupt
+                         * This matches the old behaviour.
+                         */
+                        rc = 1;
+                } else
+                        printk(KERN_WARNING "Unknown enabled NMI hardware?!\n");
         }
 done:
-        return;
+        return rc;
 }
 
 #ifdef CONFIG_SYSCTL
diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index 3a07b2677e2a..282f0bd40dfd 100644
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -706,6 +706,13 @@ void die_nmi (struct pt_regs *regs, const char *msg)
         do_exit(SIGSEGV);
 }
 
+static int dummy_nmi_callback(struct pt_regs * regs, int cpu)
+{
+        return 0;
+}
+
+static nmi_callback_t nmi_callback = dummy_nmi_callback;
+
 static void default_do_nmi(struct pt_regs * regs)
 {
         unsigned char reason = 0;
@@ -723,12 +730,11 @@ static void default_do_nmi(struct pt_regs * regs)
                  * Ok, so this is none of the documented NMI sources,
                  * so it must be the NMI watchdog.
                  */
-                if (nmi_watchdog) {
-                        nmi_watchdog_tick(regs, reason);
+                if (nmi_watchdog_tick(regs, reason))
                         return;
-                }
 #endif
-                unknown_nmi_error(reason, regs);
+                if (!rcu_dereference(nmi_callback)(regs, smp_processor_id()))
+                        unknown_nmi_error(reason, regs);
                 return;
         }
         if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP)
@@ -744,13 +750,6 @@ static void default_do_nmi(struct pt_regs * regs)
         reassert_nmi();
 }
 
-static int dummy_nmi_callback(struct pt_regs * regs, int cpu)
-{
-        return 0;
-}
- 
-static nmi_callback_t nmi_callback = dummy_nmi_callback;
- 
 fastcall void do_nmi(struct pt_regs * regs, long error_code)
 {
         int cpu;
@@ -761,8 +760,7 @@ fastcall void do_nmi(struct pt_regs * regs, long error_code)
 
         ++nmi_count(cpu);
 
-        if (!rcu_dereference(nmi_callback)(regs, cpu))
-                default_do_nmi(regs);
+        default_do_nmi(regs);
 
         nmi_exit();
 }
diff --git a/arch/x86_64/kernel/nmi.c b/arch/x86_64/kernel/nmi.c
index d42374a952d7..f6b881b23a70 100644
--- a/arch/x86_64/kernel/nmi.c
+++ b/arch/x86_64/kernel/nmi.c
@@ -682,16 +682,18 @@ void touch_nmi_watchdog (void)
         touch_softlockup_watchdog();
 }
 
-void __kprobes nmi_watchdog_tick(struct pt_regs * regs, unsigned reason)
+int __kprobes nmi_watchdog_tick(struct pt_regs * regs, unsigned reason)
 {
         int sum;
         int touched = 0;
         struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);
         u64 dummy;
+        int rc=0;
 
         /* check for other users first */
         if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
                         == NOTIFY_STOP) {
+                rc = 1;
                 touched = 1;
         }
 
@@ -746,10 +748,18 @@ void __kprobes nmi_watchdog_tick(struct pt_regs * regs, unsigned reason)
                         }
                         /* start the cycle over again */
                         wrmsrl(wd->perfctr_msr, -((u64)cpu_khz * 1000 / nmi_hz));
-                }
+                        rc = 1;
+                } else  if (nmi_watchdog == NMI_IO_APIC) {
+                        /* don't know how to accurately check for this.
+                         * just assume it was a watchdog timer interrupt
+                         * This matches the old behaviour.
+                         */
+                        rc = 1;
+                } else
+                        printk(KERN_WARNING "Unknown enabled NMI hardware?!\n");
         }
 done:
-        return;
+        return rc;
 }
 
 static __kprobes int dummy_nmi_callback(struct pt_regs * regs, int cpu)
@@ -761,15 +771,17 @@ static nmi_callback_t nmi_callback = dummy_nmi_callback;
  
 asmlinkage __kprobes void do_nmi(struct pt_regs * regs, long error_code)
 {
-        int cpu = safe_smp_processor_id();
-
         nmi_enter();
         add_pda(__nmi_count,1);
-        if (!rcu_dereference(nmi_callback)(regs, cpu))
-                default_do_nmi(regs);
+        default_do_nmi(regs);
         nmi_exit();
 }
 
+int do_nmi_callback(struct pt_regs * regs, int cpu)
+{
+        return rcu_dereference(nmi_callback)(regs, cpu);
+}
+
 void set_nmi_callback(nmi_callback_t callback)
 {
         vmalloc_sync_all();
diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c
index b1249774d1e8..42bc070fdf11 100644
--- a/arch/x86_64/kernel/traps.c
+++ b/arch/x86_64/kernel/traps.c
@@ -781,12 +781,12 @@ asmlinkage __kprobes void default_do_nmi(struct pt_regs *regs)
                  * Ok, so this is none of the documented NMI sources,
                  * so it must be the NMI watchdog.
                  */
-                if (nmi_watchdog > 0) {
-                        nmi_watchdog_tick(regs,reason);
+                if (nmi_watchdog_tick(regs,reason))
                         return;
-                }
+                if (!do_nmi_callback(regs,cpu))
 #endif
-                unknown_nmi_error(reason, regs);
+                        unknown_nmi_error(reason, regs);
+
                 return;
         }
         if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP)
diff --git a/include/asm-i386/nmi.h b/include/asm-i386/nmi.h
index 4cda6801ecb8..da0e0b4e9139 100644
--- a/include/asm-i386/nmi.h
+++ b/include/asm-i386/nmi.h
@@ -37,7 +37,7 @@ extern int reserve_lapic_nmi(void);
 extern void release_lapic_nmi(void);
 extern void disable_timer_nmi_watchdog(void);
 extern void enable_timer_nmi_watchdog(void);
-extern void nmi_watchdog_tick (struct pt_regs * regs, unsigned reason);
+extern int nmi_watchdog_tick (struct pt_regs * regs, unsigned reason);
 
 extern atomic_t nmi_active;
 extern unsigned int nmi_watchdog;
diff --git a/include/asm-x86_64/nmi.h b/include/asm-x86_64/nmi.h
index 5918136fd853..8f02a2a416e6 100644
--- a/include/asm-x86_64/nmi.h
+++ b/include/asm-x86_64/nmi.h
@@ -26,6 +26,14 @@ void set_nmi_callback(nmi_callback_t callback);
  */
 void unset_nmi_callback(void);
 
+/**
+ * do_nmi_callback
+ *
+ * Check to see if a callback exists and execute it.  Return 1
+ * if the handler exists and was handled successfully.
+ */
+int do_nmi_callback(struct pt_regs *regs, int cpu);
+
 #ifdef CONFIG_PM
  
 /** Replace the PM callback routine for NMI. */
@@ -68,7 +76,7 @@ extern int reserve_lapic_nmi(void);
 extern void release_lapic_nmi(void);
 extern void disable_timer_nmi_watchdog(void);
 extern void enable_timer_nmi_watchdog(void);
-extern void nmi_watchdog_tick (struct pt_regs * regs, unsigned reason);
+extern int nmi_watchdog_tick (struct pt_regs * regs, unsigned reason);
 
 extern void nmi_watchdog_default(void);
 extern int setup_nmi_watchdog(char *);