root/arch/x86/kernel/apic/hw_nmi.c

DEFINITIONS

1. hw_nmi_get_sample_period
2. nmi_raise_cpu_backtrace
3. arch_trigger_cpumask_backtrace
4. nmi_cpu_backtrace_handler
5. register_nmi_cpu_backtrace_handler

   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 <asm/apic.h>
  13 #include <asm/nmi.h>
  14 
  15 #include <linux/cpumask.h>
  16 #include <linux/kdebug.h>
  17 #include <linux/notifier.h>
  18 #include <linux/kprobes.h>
  19 #include <linux/nmi.h>
  20 #include <linux/init.h>
  21 #include <linux/delay.h>
  22 
  23 #ifdef CONFIG_HARDLOCKUP_DETECTOR_PERF
  24 u64 hw_nmi_get_sample_period(int watchdog_thresh)
  25 {
  26         return (u64)(cpu_khz) * 1000 * watchdog_thresh;
  27 }
  28 #endif
  29 
  30 #ifdef arch_trigger_cpumask_backtrace
  31 static void nmi_raise_cpu_backtrace(cpumask_t *mask)
  32 {
  33         apic->send_IPI_mask(mask, NMI_VECTOR);
  34 }
  35 
  36 void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
  37 {
  38         nmi_trigger_cpumask_backtrace(mask, exclude_self,
  39                                       nmi_raise_cpu_backtrace);
  40 }
  41 
  42 static int nmi_cpu_backtrace_handler(unsigned int cmd, struct pt_regs *regs)
  43 {
  44         if (nmi_cpu_backtrace(regs))
  45                 return NMI_HANDLED;
  46 
  47         return NMI_DONE;
  48 }
  49 NOKPROBE_SYMBOL(nmi_cpu_backtrace_handler);
  50 
  51 static int __init register_nmi_cpu_backtrace_handler(void)
  52 {
  53         register_nmi_handler(NMI_LOCAL, nmi_cpu_backtrace_handler,
  54                                 0, "arch_bt");
  55         return 0;
  56 }
  57 early_initcall(register_nmi_cpu_backtrace_handler);
  58 #endif