x86, nmi_watchdog: Remove ARCH_HAS_NMI_WATCHDOG and rely on CONFIG_HARDLOCKUP_DETECTOR
[linux-2.6.git] / arch / x86 / kernel / apic / hw_nmi.c
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
20 #ifdef CONFIG_HARDLOCKUP_DETECTOR
21 u64 hw_nmi_get_sample_period(void)
22 {
23         return (u64)(cpu_khz) * 1000 * 60;
24 }
25 #endif
26
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;
30
31 void arch_trigger_all_cpu_backtrace(void)
32 {
33         int i;
34
35         cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask);
36
37         printk(KERN_INFO "sending NMI to all CPUs:\n");
38         apic->send_IPI_all(NMI_VECTOR);
39
40         /* Wait for up to 10 seconds for all CPUs to do the backtrace */
41         for (i = 0; i < 10 * 1000; i++) {
42                 if (cpumask_empty(to_cpumask(backtrace_mask)))
43                         break;
44                 mdelay(1);
45         }
46 }
47
48 static int __kprobes
49 arch_trigger_all_cpu_backtrace_handler(struct notifier_block *self,
50                          unsigned long cmd, void *__args)
51 {
52         struct die_args *args = __args;
53         struct pt_regs *regs;
54         int cpu = smp_processor_id();
55
56         switch (cmd) {
57         case DIE_NMI:
58         case DIE_NMI_IPI:
59                 break;
60
61         default:
62                 return NOTIFY_DONE;
63         }
64
65         regs = args->regs;
66
67         if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
68                 static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
69
70                 arch_spin_lock(&lock);
71                 printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
72                 show_regs(regs);
73                 dump_stack();
74                 arch_spin_unlock(&lock);
75                 cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
76                 return NOTIFY_STOP;
77         }
78
79         return NOTIFY_DONE;
80 }
81
82 static __read_mostly struct notifier_block backtrace_notifier = {
83         .notifier_call          = arch_trigger_all_cpu_backtrace_handler,
84         .next                   = NULL,
85         .priority               = 1
86 };
87
88 static int __init register_trigger_all_cpu_backtrace(void)
89 {
90         register_die_notifier(&backtrace_notifier);
91         return 0;
92 }
93 early_initcall(register_trigger_all_cpu_backtrace);
94 #endif