arch/x86/kernel/apic/hw_nmi.c

   1 /*
   2  *  HW NMI watchdog support
   3  *
   4  *  started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
   5  *
   6  *  Arch specific calls to support NMI watchdog
   7  *
   8  *  Bits copied from original nmi.c file
   9  *
  10  */
  11 #include <asm/apic.h>
  12
  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
  20 #ifdef CONFIG_HARDLOCKUP_DETECTOR
  21 u64 hw_nmi_get_sample_period(void)
  22 {
  23         return (u64)(cpu_khz) * 1000 * 60;
  24 }
  25 #endif
  26
  27 #ifndef CONFIG_HARDLOCKUP_DETECTOR
  28 void touch_nmi_watchdog(void)
  29 {
  30         touch_softlockup_watchdog();
  31 }
  32 EXPORT_SYMBOL(touch_nmi_watchdog);
  33 #endif
  34 #ifdef arch_trigger_all_cpu_backtrace
  35 /* For reliability, we're prepared to waste bits here. */
  36 static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
  37
  38 void arch_trigger_all_cpu_backtrace(void)
  39 {
  40         int i;
  41
  42         cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask);
  43
  44         printk(KERN_INFO "sending NMI to all CPUs:\n");
  45         apic->send_IPI_all(NMI_VECTOR);
  46
  47         /* Wait for up to 10 seconds for all CPUs to do the backtrace */
  48         for (i = 0; i < 10 * 1000; i++) {
  49                 if (cpumask_empty(to_cpumask(backtrace_mask)))
  50                         break;
  51                 mdelay(1);
  52         }
  53 }
  54
  55 static int __kprobes
  56 arch_trigger_all_cpu_backtrace_handler(struct notifier_block *self,
  57                          unsigned long cmd, void *__args)
  58 {
  59         struct die_args *args = __args;
  60         struct pt_regs *regs;
  61         int cpu = smp_processor_id();
  62
  63         switch (cmd) {
  64         case DIE_NMI:
  65         case DIE_NMI_IPI:
  66                 break;
  67
  68         default:
  69                 return NOTIFY_DONE;
  70         }
  71
  72         regs = args->regs;
  73
  74         if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
  75                 static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
  76
  77                 arch_spin_lock(&lock);
  78                 printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
  79                 show_regs(regs);
  80                 dump_stack();
  81                 arch_spin_unlock(&lock);
  82                 cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
  83                 return NOTIFY_STOP;
  84         }
  85
  86         return NOTIFY_DONE;
  87 }
  88
  89 static __read_mostly struct notifier_block backtrace_notifier = {
  90         .notifier_call          = arch_trigger_all_cpu_backtrace_handler,
  91         .next                   = NULL,
  92         .priority               = 1
  93 };
  94
  95 static int __init register_trigger_all_cpu_backtrace(void)
  96 {
  97         register_die_notifier(&backtrace_notifier);
  98         return 0;
  99 }
 100 early_initcall(register_trigger_all_cpu_backtrace);
 101 #endif
 102
 103 /* STUB calls to mimic old nmi_watchdog behaviour */
 104 int unknown_nmi_panic;