Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6
[pandora-kernel.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 /* For reliability, we're prepared to waste bits here. */
21 static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
22
23 u64 hw_nmi_get_sample_period(void)
24 {
25         return (u64)(cpu_khz) * 1000 * 60;
26 }
27
28 #ifdef ARCH_HAS_NMI_WATCHDOG
29 void arch_trigger_all_cpu_backtrace(void)
30 {
31         int i;
32
33         cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask);
34
35         printk(KERN_INFO "sending NMI to all CPUs:\n");
36         apic->send_IPI_all(NMI_VECTOR);
37
38         /* Wait for up to 10 seconds for all CPUs to do the backtrace */
39         for (i = 0; i < 10 * 1000; i++) {
40                 if (cpumask_empty(to_cpumask(backtrace_mask)))
41                         break;
42                 mdelay(1);
43         }
44 }
45
46 static int __kprobes
47 arch_trigger_all_cpu_backtrace_handler(struct notifier_block *self,
48                          unsigned long cmd, void *__args)
49 {
50         struct die_args *args = __args;
51         struct pt_regs *regs;
52         int cpu = smp_processor_id();
53
54         switch (cmd) {
55         case DIE_NMI:
56         case DIE_NMI_IPI:
57                 break;
58
59         default:
60                 return NOTIFY_DONE;
61         }
62
63         regs = args->regs;
64
65         if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
66                 static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
67
68                 arch_spin_lock(&lock);
69                 printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
70                 show_regs(regs);
71                 dump_stack();
72                 arch_spin_unlock(&lock);
73                 cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
74                 return NOTIFY_STOP;
75         }
76
77         return NOTIFY_DONE;
78 }
79
80 static __read_mostly struct notifier_block backtrace_notifier = {
81         .notifier_call          = arch_trigger_all_cpu_backtrace_handler,
82         .next                   = NULL,
83         .priority               = 1
84 };
85
86 static int __init register_trigger_all_cpu_backtrace(void)
87 {
88         register_die_notifier(&backtrace_notifier);
89         return 0;
90 }
91 early_initcall(register_trigger_all_cpu_backtrace);
92 #endif
93
94 /* STUB calls to mimic old nmi_watchdog behaviour */
95 #if defined(CONFIG_X86_LOCAL_APIC)
96 unsigned int nmi_watchdog = NMI_NONE;
97 EXPORT_SYMBOL(nmi_watchdog);
98 void acpi_nmi_enable(void) { return; }
99 void acpi_nmi_disable(void) { return; }
100 #endif
101 atomic_t nmi_active = ATOMIC_INIT(0);           /* oprofile uses this */
102 EXPORT_SYMBOL(nmi_active);
103 int unknown_nmi_panic;
104 void cpu_nmi_set_wd_enabled(void) { return; }
105 void stop_apic_nmi_watchdog(void *unused) { return; }
106 void setup_apic_nmi_watchdog(void *unused) { return; }
107 int __init check_nmi_watchdog(void) { return 0; }