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
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>
22 #ifdef CONFIG_HARDLOCKUP_DETECTOR
23 u64
hw_nmi_get_sample_period(int watchdog_thresh
)
25 return (u64
)(cpu_khz
) * 1000 * watchdog_thresh
;
29 #ifdef arch_trigger_all_cpu_backtrace
30 /* For reliability, we're prepared to waste bits here. */
31 static DECLARE_BITMAP(backtrace_mask
, NR_CPUS
) __read_mostly
;
33 /* "in progress" flag of arch_trigger_all_cpu_backtrace */
34 static unsigned long backtrace_flag
;
36 void arch_trigger_all_cpu_backtrace(bool include_self
)
41 if (test_and_set_bit(0, &backtrace_flag
)) {
43 * If there is already a trigger_all_cpu_backtrace() in progress
44 * (backtrace_flag == 1), don't output double cpu dump infos.
50 cpumask_copy(to_cpumask(backtrace_mask
), cpu_online_mask
);
52 cpumask_clear_cpu(cpu
, to_cpumask(backtrace_mask
));
54 if (!cpumask_empty(to_cpumask(backtrace_mask
))) {
55 pr_info("sending NMI to %s CPUs:\n",
56 (include_self
? "all" : "other"));
57 apic
->send_IPI_mask(to_cpumask(backtrace_mask
), NMI_VECTOR
);
60 /* Wait for up to 10 seconds for all CPUs to do the backtrace */
61 for (i
= 0; i
< 10 * 1000; i
++) {
62 if (cpumask_empty(to_cpumask(backtrace_mask
)))
65 touch_softlockup_watchdog();
68 clear_bit(0, &backtrace_flag
);
69 smp_mb__after_atomic();
74 arch_trigger_all_cpu_backtrace_handler(unsigned int cmd
, struct pt_regs
*regs
)
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
);
86 arch_spin_unlock(&lock
);
87 cpumask_clear_cpu(cpu
, to_cpumask(backtrace_mask
));
93 NOKPROBE_SYMBOL(arch_trigger_all_cpu_backtrace_handler
);
95 static int __init
register_trigger_all_cpu_backtrace(void)
97 register_nmi_handler(NMI_LOCAL
, arch_trigger_all_cpu_backtrace_handler
,
101 early_initcall(register_trigger_all_cpu_backtrace
);