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 62