2 * HW NMI watchdog support
4 * started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
6 * Arch specific calls to support NMI watchdog
8 * Bits copied from original nmi.c file
13 #include <linux/cpumask.h>
14 #include <linux/kdebug.h>
15 #include <linux/notifier.h>
16 #include <linux/kprobes.h>
17 #include <linux/nmi.h>
18 #include <linux/module.h>
20 u64 hw_nmi_get_sample_period(void)
22 return (u64)(cpu_khz) * 1000 * 60;
25 #ifdef ARCH_HAS_NMI_WATCHDOG
27 /* For reliability, we're prepared to waste bits here. */
28 static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
30 void arch_trigger_all_cpu_backtrace(void)
34 cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask);
36 printk(KERN_INFO "sending NMI to all CPUs:\n");
37 apic->send_IPI_all(NMI_VECTOR);
39 /* Wait for up to 10 seconds for all CPUs to do the backtrace */
40 for (i = 0; i < 10 * 1000; i++) {
41 if (cpumask_empty(to_cpumask(backtrace_mask)))
48 arch_trigger_all_cpu_backtrace_handler(struct notifier_block *self,
49 unsigned long cmd, void *__args)
51 struct die_args *args = __args;
53 int cpu = smp_processor_id();
66 if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
67 static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
69 arch_spin_lock(&lock);
70 printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
73 arch_spin_unlock(&lock);
74 cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
81 static __read_mostly struct notifier_block backtrace_notifier = {
82 .notifier_call = arch_trigger_all_cpu_backtrace_handler,
87 static int __init register_trigger_all_cpu_backtrace(void)
89 register_die_notifier(&backtrace_notifier);
92 early_initcall(register_trigger_all_cpu_backtrace);
95 /* STUB calls to mimic old nmi_watchdog behaviour */
96 #if defined(CONFIG_X86_LOCAL_APIC)
97 unsigned int nmi_watchdog = NMI_NONE;
98 EXPORT_SYMBOL(nmi_watchdog);
99 void acpi_nmi_enable(void) { return; }
100 void acpi_nmi_disable(void) { return; }
102 atomic_t nmi_active = ATOMIC_INIT(0); /* oprofile uses this */
103 EXPORT_SYMBOL(nmi_active);
104 int unknown_nmi_panic;
105 void cpu_nmi_set_wd_enabled(void) { return; }
106 void stop_apic_nmi_watchdog(void *unused) { return; }
107 void setup_apic_nmi_watchdog(void *unused) { return; }
108 int __init check_nmi_watchdog(void) { return 0; }