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 #include <asm/nmi.h>
  13
  14 #include <linux/cpumask.h>
  15 #include <linux/kdebug.h>
  16 #include <linux/notifier.h>
  17 #include <linux/kprobes.h>
  18 #include <linux/nmi.h>
  19 #include <linux/module.h>
  20 #include <linux/delay.h>
  21 #include <linux/perf_event.h>
  22
  23 #ifdef CONFIG_HARDLOCKUP_DETECTOR
  24 int hw_nmi_get_event(void)
  25 {
  26         if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
  27                 return PERF_COUNT_HW_REF_CPU_CYCLES;
  28         return PERF_COUNT_HW_CPU_CYCLES;
  29 }
  30
  31 u64 hw_nmi_get_sample_period(int watchdog_thresh)
  32 {
  33         return (u64)(cpu_khz) * 1000 * watchdog_thresh;
  34 }
  35 #endif
  36
  37 #ifdef arch_trigger_all_cpu_backtrace
  38 static void nmi_raise_cpu_backtrace(cpumask_t *mask)
  39 {
  40         apic->send_IPI_mask(mask, NMI_VECTOR);
  41 }
  42
  43 void arch_trigger_all_cpu_backtrace(bool include_self)
  44 {
  45         nmi_trigger_all_cpu_backtrace(include_self, nmi_raise_cpu_backtrace);
  46 }
  47
  48 static int
  49 arch_trigger_all_cpu_backtrace_handler(unsigned int cmd, struct pt_regs *regs)
  50 {
  51         if (nmi_cpu_backtrace(regs))
  52                 return NMI_HANDLED;
  53
  54         return NMI_DONE;
  55 }
  56 NOKPROBE_SYMBOL(arch_trigger_all_cpu_backtrace_handler);
  57
  58 static int __init register_trigger_all_cpu_backtrace(void)
  59 {
  60         register_nmi_handler(NMI_LOCAL, arch_trigger_all_cpu_backtrace_handler,
  61                                 0, "arch_bt");
  62         return 0;
  63 }
  64 early_initcall(register_trigger_all_cpu_backtrace);
  65 #endif