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5dc3055879
Originally adapted from Huang Ying's patch which moved the unknown_nmi_panic to the traps.c file. Because the old nmi watchdog was deleted before this change happened, the unknown_nmi_panic sysctl was lost. This re-adds it. Also, the nmi_watchdog sysctl was re-implemented and its documentation updated accordingly. Patch-inspired-by: Huang Ying <ying.huang@intel.com> Signed-off-by: Don Zickus <dzickus@redhat.com> Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com> Acked-by: Yinghai Lu <yinghai@kernel.org> Cc: fweisbec@gmail.com LKML-Reference: <1291068437-5331-3-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
102 lines
2.2 KiB
C
102 lines
2.2 KiB
C
/*
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* HW NMI watchdog support
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*
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* started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
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*
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* Arch specific calls to support NMI watchdog
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*
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* Bits copied from original nmi.c file
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*
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*/
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#include <asm/apic.h>
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#include <linux/cpumask.h>
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#include <linux/kdebug.h>
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#include <linux/notifier.h>
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#include <linux/kprobes.h>
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#include <linux/nmi.h>
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#include <linux/module.h>
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#ifdef CONFIG_HARDLOCKUP_DETECTOR
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u64 hw_nmi_get_sample_period(void)
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{
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return (u64)(cpu_khz) * 1000 * 60;
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}
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#endif
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#ifndef CONFIG_HARDLOCKUP_DETECTOR
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void touch_nmi_watchdog(void)
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{
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touch_softlockup_watchdog();
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}
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EXPORT_SYMBOL(touch_nmi_watchdog);
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#endif
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#ifdef arch_trigger_all_cpu_backtrace
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/* For reliability, we're prepared to waste bits here. */
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static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
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void arch_trigger_all_cpu_backtrace(void)
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{
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int i;
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cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask);
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printk(KERN_INFO "sending NMI to all CPUs:\n");
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apic->send_IPI_all(NMI_VECTOR);
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/* Wait for up to 10 seconds for all CPUs to do the backtrace */
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for (i = 0; i < 10 * 1000; i++) {
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if (cpumask_empty(to_cpumask(backtrace_mask)))
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break;
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mdelay(1);
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}
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}
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static int __kprobes
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arch_trigger_all_cpu_backtrace_handler(struct notifier_block *self,
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unsigned long cmd, void *__args)
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{
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struct die_args *args = __args;
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struct pt_regs *regs;
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int cpu = smp_processor_id();
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switch (cmd) {
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case DIE_NMI:
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case DIE_NMI_IPI:
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break;
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default:
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return NOTIFY_DONE;
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}
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regs = args->regs;
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if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
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static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
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arch_spin_lock(&lock);
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printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
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show_regs(regs);
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dump_stack();
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arch_spin_unlock(&lock);
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cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
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return NOTIFY_STOP;
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}
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return NOTIFY_DONE;
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}
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static __read_mostly struct notifier_block backtrace_notifier = {
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.notifier_call = arch_trigger_all_cpu_backtrace_handler,
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.next = NULL,
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.priority = 1
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};
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static int __init register_trigger_all_cpu_backtrace(void)
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{
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register_die_notifier(&backtrace_notifier);
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return 0;
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}
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early_initcall(register_trigger_all_cpu_backtrace);
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#endif
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