kernel/apic/hw_nmi.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  *  HW NMI watchdog support
0004  *
0005  *  started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
0006  *
0007  *  Arch specific calls to support NMI watchdog
0008  *
0009  *  Bits copied from original nmi.c file
0010  *
0011  */
0012 #include <linux/thread_info.h>
0013 #include <asm/apic.h>
0014 #include <asm/nmi.h>
0015
0016 #include <linux/cpumask.h>
0017 #include <linux/kdebug.h>
0018 #include <linux/notifier.h>
0019 #include <linux/kprobes.h>
0020 #include <linux/nmi.h>
0021 #include <linux/init.h>
0022 #include <linux/delay.h>
0023
0024 #ifdef CONFIG_HARDLOCKUP_DETECTOR_PERF
0025 u64 hw_nmi_get_sample_period(int watchdog_thresh)
0026 {
0027     return (u64)(cpu_khz) * 1000 * watchdog_thresh;
0028 }
0029 #endif
0030
0031 #ifdef arch_trigger_cpumask_backtrace
0032 static void nmi_raise_cpu_backtrace(cpumask_t *mask)
0033 {
0034     apic->send_IPI_mask(mask, NMI_VECTOR);
0035 }
0036
0037 void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
0038 {
0039     nmi_trigger_cpumask_backtrace(mask, exclude_self,
0040                       nmi_raise_cpu_backtrace);
0041 }
0042
0043 static int nmi_cpu_backtrace_handler(unsigned int cmd, struct pt_regs *regs)
0044 {
0045     if (nmi_cpu_backtrace(regs))
0046         return NMI_HANDLED;
0047
0048     return NMI_DONE;
0049 }
0050 NOKPROBE_SYMBOL(nmi_cpu_backtrace_handler);
0051
0052 static int __init register_nmi_cpu_backtrace_handler(void)
0053 {
0054     register_nmi_handler(NMI_LOCAL, nmi_cpu_backtrace_handler,
0055                 0, "arch_bt");
0056     return 0;
0057 }
0058 early_initcall(register_nmi_cpu_backtrace_handler);
0059 #endif