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>
19 #include <linux/delay.h>
21 #ifdef CONFIG_HARDLOCKUP_DETECTOR
22 u64 hw_nmi_get_sample_period(void)
24 return (u64)(cpu_khz) * 1000 * 60;
28 #ifdef arch_trigger_all_cpu_backtrace
29 /* For reliability, we're prepared to waste bits here. */
30 static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
32 /* "in progress" flag of arch_trigger_all_cpu_backtrace */
33 static unsigned long backtrace_flag;
35 void arch_trigger_all_cpu_backtrace(void)
39 if (test_and_set_bit(0, &backtrace_flag))
41 * If there is already a trigger_all_cpu_backtrace() in progress
42 * (backtrace_flag == 1), don't output double cpu dump infos.
46 cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask);
48 printk(KERN_INFO "sending NMI to all CPUs:\n");
49 apic->send_IPI_all(NMI_VECTOR);
51 /* Wait for up to 10 seconds for all CPUs to do the backtrace */
52 for (i = 0; i < 10 * 1000; i++) {
53 if (cpumask_empty(to_cpumask(backtrace_mask)))
58 clear_bit(0, &backtrace_flag);
59 smp_mb__after_clear_bit();
63 arch_trigger_all_cpu_backtrace_handler(struct notifier_block *self,
64 unsigned long cmd, void *__args)
66 struct die_args *args = __args;
79 cpu = smp_processor_id();
81 if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
82 static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
84 arch_spin_lock(&lock);
85 printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
87 arch_spin_unlock(&lock);
88 cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
95 static __read_mostly struct notifier_block backtrace_notifier = {
96 .notifier_call = arch_trigger_all_cpu_backtrace_handler,
98 .priority = NMI_LOCAL_LOW_PRIOR,
101 static int __init register_trigger_all_cpu_backtrace(void)
103 register_die_notifier(&backtrace_notifier);
106 early_initcall(register_trigger_all_cpu_backtrace);