From: Aristeu Rozanski <aris@redhat.com>
Date: Wed, 20 Aug 2008 13:16:51 -0400
Subject: [x86_64] nmi: update nmi_watchdog_tick
Message-id: 20080820171647.722271000@redhat.com
O-Subject: [RHEL5.3 PATCH 05/25] nmi: update nmi_watchdog_tick()
Bugzilla: 447618

https://bugzilla.redhat.com/show_bug.cgi?id=447618

Change nmi_watchdog_tick() to detect if the NMI was generated by the perf
counter (local APIC case).

upstream: 751521149a05e308d863d01ced61080ce1a2ec99 (and others)

diff --git a/arch/x86_64/kernel/nmi.c b/arch/x86_64/kernel/nmi.c
index effad06..8ddd38f 100644
--- a/arch/x86_64/kernel/nmi.c
+++ b/arch/x86_64/kernel/nmi.c
@@ -392,10 +392,16 @@ 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;
+	int sum, touched = 0, rc = 0;
+
+	/* check for other users first */
+	if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
+			== NOTIFY_STOP) {
+		rc = 1;
+		touched = 1;
+	}
 
 	sum = read_pda(apic_timer_irqs);
 	if (__get_cpu_var(nmi_touch)) {
@@ -418,7 +424,7 @@ void __kprobes nmi_watchdog_tick(struct pt_regs * regs, unsigned reason)
 			if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
 							== NOTIFY_STOP) {
 				local_set(&__get_cpu_var(alert_counter), 0);
-				return;
+				return 1;
 			}
 			die_nmi("NMI Watchdog detected LOCKUP on CPU %d\n", regs);
 		}
@@ -426,34 +432,24 @@ void __kprobes nmi_watchdog_tick(struct pt_regs * regs, unsigned reason)
 		__get_cpu_var(last_irq_sum) = sum;
 		local_set(&__get_cpu_var(alert_counter), 0);
 	}
-	if (nmi_perfctr_msr) {
- 		if (nmi_perfctr_msr == MSR_P4_IQ_COUNTER0) {
- 			/*
- 			 * P4 quirks:
- 			 * - An overflown perfctr will assert its interrupt
- 			 *   until the OVF flag in its CCCR is cleared.
- 			 * - LVTPC is masked on interrupt and must be
- 			 *   unmasked by the LVTPC handler.
- 			 */
- 			wrmsr(MSR_P4_IQ_CCCR0, nmi_p4_cccr_val, 0);
- 			apic_write(APIC_LVTPC, APIC_DM_NMI);
-			wrmsrl(nmi_perfctr_msr,
-			       -((u64)cpu_khz * 1000 / nmi_hz));
- 		} else if (nmi_perfctr_msr == MSR_ARCH_PERFMON_PERFCTR0) {
-			/*
-			 * For Intel based architectural perfmon
-			 * - LVTPC is masked on interrupt and must be
-			 *   unmasked by the LVTPC handler.
-			 */
-			apic_write(APIC_LVTPC, APIC_DM_NMI);
-			/* ARCH PERFMON has 32 bit counter writes */
-			wrmsr(nmi_perfctr_msr,
-			       (u32)(-((u64)cpu_khz * 1000 / nmi_hz)), 0);
-		} else {
-			wrmsrl(nmi_perfctr_msr,
-			       -((u64)cpu_khz * 1000 / nmi_hz));
-		}
-	}
+
+	/* see if the nmi watchdog went off */
+	if (!__get_cpu_var(wd_enabled))
+		return rc;
+	switch (nmi_watchdog) {
+	case NMI_LOCAL_APIC:
+		rc |= lapic_wd_event(nmi_hz);
+		break;
+	case 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;
+		break;
+ 	}
+
+	return rc;
 }
 
 static __kprobes int dummy_nmi_callback(struct pt_regs * regs, int cpu)
diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c
index 9274241..195c431 100644
--- a/arch/x86_64/kernel/traps.c
+++ b/arch/x86_64/kernel/traps.c
@@ -794,16 +794,14 @@ asmlinkage __kprobes void default_do_nmi(struct pt_regs *regs)
 		if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 2, SIGINT)
 								== NOTIFY_STOP)
 			return;
-#ifdef CONFIG_X86_LOCAL_APIC
+
 		/*
 		 * 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;
-		}
-#endif
+
 		if (!do_nmi_callback2(regs, cpu))
 			unknown_nmi_error(reason, regs);
 		return;
diff --git a/include/asm-x86_64/nmi.h b/include/asm-x86_64/nmi.h
index b5060dd..86b8bcf 100644
--- a/include/asm-x86_64/nmi.h
+++ b/include/asm-x86_64/nmi.h
@@ -85,7 +85,7 @@ 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 *);