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