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
24u64 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
31static void nmi_raise_cpu_backtrace(cpumask_t *mask)
32{
33	apic->send_IPI_mask(mask, NMI_VECTOR);
34}
 
35
36void 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
42static 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}
49NOKPROBE_SYMBOL(nmi_cpu_backtrace_handler);
50
51static 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}
57early_initcall(register_nmi_cpu_backtrace_handler);
58#endif

 
  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
 13#include <linux/cpumask.h>
 14#include <linux/kdebug.h>
 15#include <linux/notifier.h>
 16#include <linux/kprobes.h>
 17#include <linux/nmi.h>
 18#include <linux/module.h>
 19#include <linux/delay.h>
 20
 21#ifdef CONFIG_HARDLOCKUP_DETECTOR
 22u64 hw_nmi_get_sample_period(int watchdog_thresh)
 23{
 24	return (u64)(cpu_khz) * 1000 * watchdog_thresh;
 25}
 26#endif
 27
 28#ifdef arch_trigger_all_cpu_backtrace
 29/* For reliability, we're prepared to waste bits here. */
 30static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
 31
 32/* "in progress" flag of arch_trigger_all_cpu_backtrace */
 33static unsigned long backtrace_flag;
 34
 35void arch_trigger_all_cpu_backtrace(void)
 36{
 37	int i;
 38
 39	if (test_and_set_bit(0, &backtrace_flag))
 40		/*
 41		 * If there is already a trigger_all_cpu_backtrace() in progress
 42		 * (backtrace_flag == 1), don't output double cpu dump infos.
 43		 */
 44		return;
 45
 46	cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask);
 47
 48	printk(KERN_INFO "sending NMI to all CPUs:\n");
 49	apic->send_IPI_all(NMI_VECTOR);
 50
 51	/* Wait for up to 10 seconds for all CPUs to do the backtrace */
 52	for (i = 0; i < 10 * 1000; i++) {
 53		if (cpumask_empty(to_cpumask(backtrace_mask)))
 54			break;
 55		mdelay(1);
 56	}
 57
 58	clear_bit(0, &backtrace_flag);
 59	smp_mb__after_clear_bit();
 60}
 61
 62static int __kprobes
 63arch_trigger_all_cpu_backtrace_handler(struct notifier_block *self,
 64			 unsigned long cmd, void *__args)
 65{
 66	struct die_args *args = __args;
 67	struct pt_regs *regs;
 68	int cpu;
 69
 70	switch (cmd) {
 71	case DIE_NMI:
 72		break;
 73
 74	default:
 75		return NOTIFY_DONE;
 76	}
 77
 78	regs = args->regs;
 79	cpu = smp_processor_id();
 80
 81	if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
 82		static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
 83
 84		arch_spin_lock(&lock);
 85		printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
 86		show_regs(regs);
 87		arch_spin_unlock(&lock);
 88		cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
 89		return NOTIFY_STOP;
 90	}
 91
 92	return NOTIFY_DONE;
 93}
 
 94
 95static __read_mostly struct notifier_block backtrace_notifier = {
 96	.notifier_call          = arch_trigger_all_cpu_backtrace_handler,
 97	.next                   = NULL,
 98	.priority               = NMI_LOCAL_LOW_PRIOR,
 99};
100
101static int __init register_trigger_all_cpu_backtrace(void)
102{
103	register_die_notifier(&backtrace_notifier);
 
104	return 0;
105}
106early_initcall(register_trigger_all_cpu_backtrace);
107#endif