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; } 108