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Commit 7cbb7e7f authored by Don Zickus's avatar Don Zickus Committed by Frederic Weisbecker
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x86: Move trigger_all_cpu_backtrace to its own die_notifier 



As part of the transition of the nmi watchdog to something more
generic, the trigger_all_cpu_backtrace code is getting left behind.
Put it in its own die_notifier so it can still be used.

V2:
- use arch_spin_locks

Signed-off-by: default avatarDon Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
LKML-Reference: <1273266711-18706-6-git-send-email-dzickus@redhat.com>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent f69bcf60

arch/x86/kernel/apic/hw_nmi.c

+51 −14
Original line number Diff line number Diff line
@@ -17,6 +17,10 @@ 
#include <linux/cpumask.h>

#include <linux/kernel_stat.h>

#include <asm/mce.h>

#include <linux/kdebug.h>

#include <linux/notifier.h>

#include <linux/kprobes.h>





#include <linux/nmi.h>

#include <linux/module.h>
@@ -54,20 +58,6 @@ int hw_nmi_is_cpu_stuck(struct pt_regs *regs) 
	unsigned int sum;

	int cpu = smp_processor_id();



	/* FIXME: cheap hack for this check, probably should get its own

	 * die_notifier handler

	 */

	if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {

		static DEFINE_SPINLOCK(lock);	/* Serialise the printks */



		spin_lock(&lock);

		printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);

		show_regs(regs);

		dump_stack();

		spin_unlock(&lock);

		cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));

	}



	/* if we are doing an mce, just assume the cpu is not stuck */

	/* Could check oops_in_progress here too, but it's safer not to */

	if (mce_in_progress())
@@ -109,6 +99,53 @@ void arch_trigger_all_cpu_backtrace(void) 
		mdelay(1);

	}

}



static int __kprobes

arch_trigger_all_cpu_backtrace_handler(struct notifier_block *self,

			 unsigned long cmd, void *__args)

{

	struct die_args *args = __args;

	struct pt_regs *regs;

	int cpu = smp_processor_id();



	switch (cmd) {

	case DIE_NMI:

	case DIE_NMI_IPI:

		break;



	default:

		return NOTIFY_DONE;

	}



	regs = args->regs;



	if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {

		static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;



		arch_spin_lock(&lock);

		printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);

		show_regs(regs);

		dump_stack();

		arch_spin_unlock(&lock);

		cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));

		return NOTIFY_STOP;

	}



	return NOTIFY_DONE;

}



static __read_mostly struct notifier_block backtrace_notifier = {

	.notifier_call          = arch_trigger_all_cpu_backtrace_handler,

	.next                   = NULL,

	.priority               = 1

};



static int __init register_trigger_all_cpu_backtrace(void)

{

	register_die_notifier(&backtrace_notifier);

	return 0;

}

early_initcall(register_trigger_all_cpu_backtrace);

#endif



/* STUB calls to mimic old nmi_watchdog behaviour */