X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=arch%2Fx86_64%2Fkernel%2Fnmi.c;h=9cb42ecb7f8966bb90bf3426f8b82e0cad9b55cf;hb=cee324b145a1e5488b34191de670e5ed1d346ebb;hp=4d6fb047952e8abec336175d3bc5abe12dc76e76;hpb=fecf3404f4aba6d0edeba31eeb018cbb6326dff2;p=powerpc.git

diff --git a/arch/x86_64/kernel/nmi.c b/arch/x86_64/kernel/nmi.c
index 4d6fb04795..9cb42ecb7f 100644
--- a/arch/x86_64/kernel/nmi.c
+++ b/arch/x86_64/kernel/nmi.c
@@ -12,14 +12,15 @@
  *  Mikael Pettersson	: PM converted to driver model. Disable/enable API.
  */
 
+#include <linux/nmi.h>
 #include <linux/mm.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/sysdev.h>
-#include <linux/nmi.h>
 #include <linux/sysctl.h>
 #include <linux/kprobes.h>
+#include <linux/cpumask.h>
 
 #include <asm/smp.h>
 #include <asm/nmi.h>
@@ -28,6 +29,10 @@
 #include <asm/mce.h>
 #include <asm/intel_arch_perfmon.h>
 
+int unknown_nmi_panic;
+int nmi_watchdog_enabled;
+int panic_on_unrecovered_nmi;
+
 /* perfctr_nmi_owner tracks the ownership of the perfctr registers:
  * evtsel_nmi_owner tracks the ownership of the event selection
  * - different performance counters/ event selection may be reserved for
@@ -37,6 +42,8 @@
 static DEFINE_PER_CPU(unsigned, perfctr_nmi_owner);
 static DEFINE_PER_CPU(unsigned, evntsel_nmi_owner[2]);
 
+static cpumask_t backtrace_mask = CPU_MASK_NONE;
+
 /* this number is calculated from Intel's MSR_P4_CRU_ESCR5 register and it's
  * offset from MSR_P4_BSU_ESCR0.  It will be the max for all platforms (for now)
  */
@@ -186,6 +193,8 @@ void nmi_watchdog_default(void)
 		nmi_watchdog = NMI_IO_APIC;
 }
 
+static int endflag __initdata = 0;
+
 #ifdef CONFIG_SMP
 /* The performance counters used by NMI_LOCAL_APIC don't trigger when
  * the CPU is idle. To make sure the NMI watchdog really ticks on all
@@ -193,7 +202,6 @@ void nmi_watchdog_default(void)
  */
 static __init void nmi_cpu_busy(void *data)
 {
-	volatile int *endflag = data;
 	local_irq_enable_in_hardirq();
 	/* Intentionally don't use cpu_relax here. This is
 	   to make sure that the performance counter really ticks,
@@ -201,14 +209,13 @@ static __init void nmi_cpu_busy(void *data)
 	   pause instruction. On a real HT machine this is fine because
 	   all other CPUs are busy with "useless" delay loops and don't
 	   care if they get somewhat less cycles. */
-	while (*endflag == 0)
-		barrier();
+	while (endflag == 0)
+		mb();
 }
 #endif
 
 int __init check_nmi_watchdog (void)
 {
-	volatile int endflag = 0;
 	int *counts;
 	int cpu;
 
@@ -249,6 +256,7 @@ int __init check_nmi_watchdog (void)
 	if (!atomic_read(&nmi_active)) {
 		kfree(counts);
 		atomic_set(&nmi_active, -1);
+		endflag = 1;
 		return -1;
 	}
 	endflag = 1;
@@ -294,8 +302,6 @@ int __init setup_nmi_watchdog(char *str)
 	if ((nmi >= NMI_INVALID) || (nmi < NMI_NONE))
 		return 0;
 
-	if ((nmi == NMI_LOCAL_APIC) && (nmi_known_cpu() == 0))
-		return 0;  /* no lapic support */
 	nmi_watchdog = nmi;
 	return 1;
 }
@@ -778,6 +784,7 @@ int __kprobes nmi_watchdog_tick(struct pt_regs * regs, unsigned reason)
 {
 	int sum;
 	int touched = 0;
+	int cpu = smp_processor_id();
 	struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);
 	u64 dummy;
 	int rc=0;
@@ -795,6 +802,16 @@ int __kprobes nmi_watchdog_tick(struct pt_regs * regs, unsigned reason)
 		touched = 1;
 	}
 
+	if (cpu_isset(cpu, backtrace_mask)) {
+		static DEFINE_SPINLOCK(lock);	/* Serialise the printks */
+
+		spin_lock(&lock);
+		printk("NMI backtrace for cpu %d\n", cpu);
+		dump_stack();
+		spin_unlock(&lock);
+		cpu_clear(cpu, backtrace_mask);
+	}
+
 #ifdef CONFIG_X86_MCE
 	/* Could check oops_in_progress here too, but it's safer
 	   not too */
@@ -927,6 +944,19 @@ int proc_nmi_enabled(struct ctl_table *table, int write, struct file *file,
 
 #endif
 
+void __trigger_all_cpu_backtrace(void)
+{
+	int i;
+
+	backtrace_mask = cpu_online_map;
+	/* Wait for up to 10 seconds for all CPUs to do the backtrace */
+	for (i = 0; i < 10 * 1000; i++) {
+		if (cpus_empty(backtrace_mask))
+			break;
+		mdelay(1);
+	}
+}
+
 EXPORT_SYMBOL(nmi_active);
 EXPORT_SYMBOL(nmi_watchdog);
 EXPORT_SYMBOL(avail_to_resrv_perfctr_nmi);