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

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