3 files changed, 43 insertions, 14 deletions

diff --git a/arch/x86/kernel/cpu/perfctr-watchdog.c b/arch/x86/kernel/cpu/perfctr-watchdog.c
index 62c01006397..6bff382094f 100644
--- a/arch/x86/kernel/cpu/perfctr-watchdog.c
+++ b/arch/x86/kernel/cpu/perfctr-watchdog.c
@@ -295,13 +295,19 @@ static int setup_k7_watchdog(unsigned nmi_hz)
         /* setup the timer */
         wrmsr(evntsel_msr, evntsel, 0);
         write_watchdog_counter(perfctr_msr, "K7_PERFCTR0",nmi_hz);
-        apic_write(APIC_LVTPC, APIC_DM_NMI);
-        evntsel |= K7_EVNTSEL_ENABLE;
-        wrmsr(evntsel_msr, evntsel, 0);
 
+        /* initialize the wd struct before enabling */
         wd->perfctr_msr = perfctr_msr;
         wd->evntsel_msr = evntsel_msr;
         wd->cccr_msr = 0;  /* unused */
+
+        /* ok, everything is initialized, announce that we're set */
+        cpu_nmi_set_wd_enabled();
+
+        apic_write(APIC_LVTPC, APIC_DM_NMI);
+        evntsel |= K7_EVNTSEL_ENABLE;
+        wrmsr(evntsel_msr, evntsel, 0);
+
         return 1;
 }
 
@@ -379,13 +385,19 @@ static int setup_p6_watchdog(unsigned nmi_hz)
         wrmsr(evntsel_msr, evntsel, 0);
         nmi_hz = adjust_for_32bit_ctr(nmi_hz);
         write_watchdog_counter32(perfctr_msr, "P6_PERFCTR0",nmi_hz);
-        apic_write(APIC_LVTPC, APIC_DM_NMI);
-        evntsel |= P6_EVNTSEL0_ENABLE;
-        wrmsr(evntsel_msr, evntsel, 0);
 
+        /* initialize the wd struct before enabling */
         wd->perfctr_msr = perfctr_msr;
         wd->evntsel_msr = evntsel_msr;
         wd->cccr_msr = 0;  /* unused */
+
+        /* ok, everything is initialized, announce that we're set */
+        cpu_nmi_set_wd_enabled();
+
+        apic_write(APIC_LVTPC, APIC_DM_NMI);
+        evntsel |= P6_EVNTSEL0_ENABLE;
+        wrmsr(evntsel_msr, evntsel, 0);
+
         return 1;
 }
 
@@ -540,12 +552,17 @@ static int setup_p4_watchdog(unsigned nmi_hz)
         wrmsr(evntsel_msr, evntsel, 0);
         wrmsr(cccr_msr, cccr_val, 0);
         write_watchdog_counter(perfctr_msr, "P4_IQ_COUNTER0", nmi_hz);
-        apic_write(APIC_LVTPC, APIC_DM_NMI);
-        cccr_val |= P4_CCCR_ENABLE;
-        wrmsr(cccr_msr, cccr_val, 0);
+
         wd->perfctr_msr = perfctr_msr;
         wd->evntsel_msr = evntsel_msr;
         wd->cccr_msr = cccr_msr;
+
+        /* ok, everything is initialized, announce that we're set */
+        cpu_nmi_set_wd_enabled();
+
+        apic_write(APIC_LVTPC, APIC_DM_NMI);
+        cccr_val |= P4_CCCR_ENABLE;
+        wrmsr(cccr_msr, cccr_val, 0);
         return 1;
 }
 
@@ -661,13 +678,17 @@ static int setup_intel_arch_watchdog(unsigned nmi_hz)
         wrmsr(evntsel_msr, evntsel, 0);
         nmi_hz = adjust_for_32bit_ctr(nmi_hz);
         write_watchdog_counter32(perfctr_msr, "INTEL_ARCH_PERFCTR0", nmi_hz);
-        apic_write(APIC_LVTPC, APIC_DM_NMI);
-        evntsel |= ARCH_PERFMON_EVENTSEL0_ENABLE;
-        wrmsr(evntsel_msr, evntsel, 0);
 
         wd->perfctr_msr = perfctr_msr;
         wd->evntsel_msr = evntsel_msr;
         wd->cccr_msr = 0;  /* unused */
+
+        /* ok, everything is initialized, announce that we're set */
+        cpu_nmi_set_wd_enabled();
+
+        apic_write(APIC_LVTPC, APIC_DM_NMI);
+        evntsel |= ARCH_PERFMON_EVENTSEL0_ENABLE;
+        wrmsr(evntsel_msr, evntsel, 0);
         intel_arch_wd_ops.checkbit = 1ULL << (eax.split.bit_width - 1);
         return 1;
 }
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index abb78a2cc4a..2c97f07f1c2 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -299,6 +299,15 @@ void acpi_nmi_disable(void)
                 on_each_cpu(__acpi_nmi_disable, NULL, 1);
 }
 
+/*
+ * This function is called as soon the LAPIC NMI watchdog driver has everything
+ * in place and it's ready to check if the NMIs belong to the NMI watchdog
+ */
+void cpu_nmi_set_wd_enabled(void)
+{
+        __get_cpu_var(wd_enabled) = 1;
+}
+
 void setup_apic_nmi_watchdog(void *unused)
 {
         if (__get_cpu_var(wd_enabled))
@@ -311,8 +320,6 @@ void setup_apic_nmi_watchdog(void *unused)
 
         switch (nmi_watchdog) {
         case NMI_LOCAL_APIC:
-                 /* enable it before to avoid race with handler */
-                __get_cpu_var(wd_enabled) = 1;
                 if (lapic_watchdog_init(nmi_hz) < 0) {
                         __get_cpu_var(wd_enabled) = 0;
                         return;
diff --git a/include/asm-x86/nmi.h b/include/asm-x86/nmi.h
index 21f8d0202a8..02bfc81cbd6 100644
--- a/include/asm-x86/nmi.h
+++ b/include/asm-x86/nmi.h
@@ -34,6 +34,7 @@ extern void stop_apic_nmi_watchdog(void *);
 extern void disable_timer_nmi_watchdog(void);
 extern void enable_timer_nmi_watchdog(void);
 extern int nmi_watchdog_tick(struct pt_regs *regs, unsigned reason);
+extern void cpu_nmi_set_wd_enabled(void);
 
 extern atomic_t nmi_active;
 extern unsigned int nmi_watchdog;