[PATCH] NMI watchdog SMP fix

This makes NMIs work - otherwise they go to CPU 0 only and any hard
lockup on the other CPUs will not be detected by the nmi_watchdog.

arch/i386/kernel/io_apic.c

@@ -1490,7 +1490,7 @@ static struct hw_interrupt_type lapic_irq_type = {
 	end_lapic_irq
 };
 
-static void enable_NMI_through_LVT0 (void * dummy)
+void enable_NMI_through_LVT0 (void * dummy)
 {
 	unsigned int v, ver;
 

arch/i386/kernel/smpboot.c

@@ -445,6 +445,11 @@ int __init start_secondary(void *unused)
 	while (!test_bit(smp_processor_id(), &smp_commenced_mask))
 		rep_nop();
 	setup_secondary_APIC_clock();
+	if (nmi_watchdog == NMI_IO_APIC) {
+		disable_8259A_irq(0);
+		enable_NMI_through_LVT0(NULL);
+		enable_8259A_irq(0);
+	}
 	enable_APIC_timer();
 	/*
 	 * low-memory mappings have been cleared, flush them from

include/asm-i386/apic.h

@@ -89,6 +89,7 @@ extern void apic_pm_unregister(struct pm_dev*);
 
 extern unsigned int apic_timer_irqs [NR_CPUS];
 extern int check_nmi_watchdog (void);
+extern void enable_NMI_through_LVT0 (void * dummy);
 
 extern unsigned int nmi_watchdog;
 #define NMI_NONE	0