arch/x86/kernel/apic/hw_nmi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  HW NMI watchdog support
   4  *
   5  *  started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
   6  *
   7  *  Arch specific calls to support NMI watchdog
   8  *
   9  *  Bits copied from original nmi.c file
  10  *
  11  */
  12 #include <linux/thread_info.h>
  13 #include <asm/apic.h>
  14 #include <asm/nmi.h>
  15
  16 #include <linux/cpumask.h>
  17 #include <linux/kdebug.h>
  18 #include <linux/notifier.h>
  19 #include <linux/kprobes.h>
  20 #include <linux/nmi.h>
  21 #include <linux/init.h>
  22 #include <linux/delay.h>
  23
  24 #include "local.h"
  25
  26 #ifdef CONFIG_HARDLOCKUP_DETECTOR_PERF
  27 u64 hw_nmi_get_sample_period(int watchdog_thresh)
  28 {
  29         return (u64)(cpu_khz) * 1000 * watchdog_thresh;
  30 }
  31 #endif
  32
  33 #ifdef arch_trigger_cpumask_backtrace
  34 static void nmi_raise_cpu_backtrace(cpumask_t *mask)
  35 {
  36         __apic_send_IPI_mask(mask, NMI_VECTOR);
  37 }
  38
  39 void arch_trigger_cpumask_backtrace(const cpumask_t *mask, int exclude_cpu)
  40 {
  41         nmi_trigger_cpumask_backtrace(mask, exclude_cpu,
  42                                       nmi_raise_cpu_backtrace);
  43 }
  44
  45 static int nmi_cpu_backtrace_handler(unsigned int cmd, struct pt_regs *regs)
  46 {
  47         if (nmi_cpu_backtrace(regs))
  48                 return NMI_HANDLED;
  49
  50         return NMI_DONE;
  51 }
  52 NOKPROBE_SYMBOL(nmi_cpu_backtrace_handler);
  53
  54 static int __init register_nmi_cpu_backtrace_handler(void)
  55 {
  56         register_nmi_handler(NMI_LOCAL, nmi_cpu_backtrace_handler,
  57                                 0, "arch_bt");
  58         return 0;
  59 }
  60 early_initcall(register_nmi_cpu_backtrace_handler);
  61 #endif