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(unsigned int cmd, struct pt_regs *regs)
64{
65	int cpu;
66
67	cpu = smp_processor_id();
68
69	if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
70		static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
71
72		arch_spin_lock(&lock);
73		printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
74		show_regs(regs);
75		arch_spin_unlock(&lock);
76		cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
77		return NMI_HANDLED;
78	}
79
80	return NMI_DONE;
81}
 
82
83static int __init register_trigger_all_cpu_backtrace(void)
84{
85	register_nmi_handler(NMI_LOCAL, arch_trigger_all_cpu_backtrace_handler,
86				0, "arch_bt");
87	return 0;
88}
89early_initcall(register_trigger_all_cpu_backtrace);
90#endif