2 * HW NMI watchdog support
4 * started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
6 * Arch specific calls to support NMI watchdog
8 * Bits copied from original nmi.c file
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>
20 #ifdef CONFIG_HARDLOCKUP_DETECTOR
21 u64
hw_nmi_get_sample_period(void)
23 return (u64
)(cpu_khz
) * 1000 * 60;
27 #ifdef arch_trigger_all_cpu_backtrace
28 /* For reliability, we're prepared to waste bits here. */
29 static DECLARE_BITMAP(backtrace_mask
, NR_CPUS
) __read_mostly
;
31 /* "in progress" flag of arch_trigger_all_cpu_backtrace */
32 static unsigned long backtrace_flag
;
34 void arch_trigger_all_cpu_backtrace(void)
38 if (test_and_set_bit(0, &backtrace_flag
))
40 * If there is already a trigger_all_cpu_backtrace() in progress
41 * (backtrace_flag == 1), don't output double cpu dump infos.
45 cpumask_copy(to_cpumask(backtrace_mask
), cpu_online_mask
);
47 printk(KERN_INFO
"sending NMI to all CPUs:\n");
48 apic
->send_IPI_all(NMI_VECTOR
);
50 /* Wait for up to 10 seconds for all CPUs to do the backtrace */
51 for (i
= 0; i
< 10 * 1000; i
++) {
52 if (cpumask_empty(to_cpumask(backtrace_mask
)))
57 clear_bit(0, &backtrace_flag
);
58 smp_mb__after_clear_bit();
62 arch_trigger_all_cpu_backtrace_handler(struct notifier_block
*self
,
63 unsigned long cmd
, void *__args
)
65 struct die_args
*args
= __args
;
78 cpu
= smp_processor_id();
80 if (cpumask_test_cpu(cpu
, to_cpumask(backtrace_mask
))) {
81 static arch_spinlock_t lock
= __ARCH_SPIN_LOCK_UNLOCKED
;
83 arch_spin_lock(&lock
);
84 printk(KERN_WARNING
"NMI backtrace for cpu %d\n", cpu
);
87 arch_spin_unlock(&lock
);
88 cpumask_clear_cpu(cpu
, to_cpumask(backtrace_mask
));
95 static __read_mostly
struct notifier_block backtrace_notifier
= {
96 .notifier_call
= arch_trigger_all_cpu_backtrace_handler
,
98 .priority
= NMI_LOCAL_LOW_PRIOR
,
101 static int __init
register_trigger_all_cpu_backtrace(void)
103 register_die_notifier(&backtrace_notifier
);
106 early_initcall(register_trigger_all_cpu_backtrace
);