lockup_detector: Remove nmi_watchdog.c file

/*

 * Detect Hard Lockups using the NMI

 *

 * started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.

 *

 * this code detects hard lockups: incidents in where on a CPU

 * the kernel does not respond to anything except NMI.

 *

 * Note: Most of this code is borrowed heavily from softlockup.c,

 * so thanks to Ingo for the initial implementation.

 * Some chunks also taken from arch/x86/kernel/apic/nmi.c, thanks

 * to those contributors as well.

 */

#include <linux/mm.h>

#include <linux/cpu.h>

#include <linux/nmi.h>

#include <linux/init.h>

#include <linux/delay.h>

#include <linux/freezer.h>

#include <linux/lockdep.h>

#include <linux/notifier.h>

#include <linux/module.h>

#include <linux/sysctl.h>

#include <asm/irq_regs.h>

#include <linux/perf_event.h>

static DEFINE_PER_CPU(struct perf_event *, nmi_watchdog_ev);

static DEFINE_PER_CPU(int, nmi_watchdog_touch);

static DEFINE_PER_CPU(long, alert_counter);

static int panic_on_timeout;

void touch_nmi_watchdog(void)

{

	__raw_get_cpu_var(nmi_watchdog_touch) = 1;

	touch_softlockup_watchdog();

}

EXPORT_SYMBOL(touch_nmi_watchdog);

void touch_all_nmi_watchdog(void)

{

	int cpu;

	for_each_online_cpu(cpu)

		per_cpu(nmi_watchdog_touch, cpu) = 1;

	touch_softlockup_watchdog();

}

static int __init setup_nmi_watchdog(char *str)

{

	if (!strncmp(str, "panic", 5)) {

		panic_on_timeout = 1;

		str = strchr(str, ',');

		if (!str)

			return 1;

		++str;

	}

	return 1;

}

__setup("nmi_watchdog=", setup_nmi_watchdog);

struct perf_event_attr wd_hw_attr = {

	.type		= PERF_TYPE_HARDWARE,

	.config		= PERF_COUNT_HW_CPU_CYCLES,

	.size		= sizeof(struct perf_event_attr),

	.pinned		= 1,

	.disabled	= 1,

};

struct perf_event_attr wd_sw_attr = {

	.type		= PERF_TYPE_SOFTWARE,

	.config		= PERF_COUNT_SW_CPU_CLOCK,

	.size		= sizeof(struct perf_event_attr),

	.pinned		= 1,

	.disabled	= 1,

};

void wd_overflow(struct perf_event *event, int nmi,

		 struct perf_sample_data *data,

		 struct pt_regs *regs)

{

	int cpu = smp_processor_id();

	int touched = 0;

	if (__get_cpu_var(nmi_watchdog_touch)) {

		per_cpu(nmi_watchdog_touch, cpu) = 0;

		touched = 1;

	}

	/* check to see if the cpu is doing anything */

	if (!touched && hw_nmi_is_cpu_stuck(regs)) {

		/*

		 * Ayiee, looks like this CPU is stuck ...

		 * wait a few IRQs (5 seconds) before doing the oops ...

		 */

		per_cpu(alert_counter, cpu) += 1;

		if (per_cpu(alert_counter, cpu) == 5) {

			if (panic_on_timeout)

				panic("NMI Watchdog detected LOCKUP on cpu %d", cpu);

			else

				WARN(1, "NMI Watchdog detected LOCKUP on cpu %d", cpu);

		}

	} else {

		per_cpu(alert_counter, cpu) = 0;

	}

	return;

}

static int enable_nmi_watchdog(int cpu)

{

	struct perf_event *event;

	struct perf_event_attr *wd_attr;

	event = per_cpu(nmi_watchdog_ev, cpu);

	if (event && event->state > PERF_EVENT_STATE_OFF)

		return 0;

	if (event == NULL) {

		/* Try to register using hardware perf events first */

		wd_attr = &wd_hw_attr;

		wd_attr->sample_period = hw_nmi_get_sample_period();

		event = perf_event_create_kernel_counter(wd_attr, cpu, -1, wd_overflow);

		if (IS_ERR(event)) {

			/* hardware doesn't exist or not supported, fallback to software events */

			printk(KERN_INFO "nmi_watchdog: hardware not available, trying software events\n");

			wd_attr = &wd_sw_attr;

			wd_attr->sample_period = NSEC_PER_SEC;

			event = perf_event_create_kernel_counter(wd_attr, cpu, -1, wd_overflow);

			if (IS_ERR(event)) {

				printk(KERN_ERR "nmi watchdog failed to create perf event on %i: %p\n", cpu, event);

				return -1;

			}

		}

		per_cpu(nmi_watchdog_ev, cpu) = event;

	}

	perf_event_enable(per_cpu(nmi_watchdog_ev, cpu));

	return 0;

}

static void disable_nmi_watchdog(int cpu)

{

	struct perf_event *event;

	event = per_cpu(nmi_watchdog_ev, cpu);

	if (event) {

		perf_event_disable(per_cpu(nmi_watchdog_ev, cpu));

		per_cpu(nmi_watchdog_ev, cpu) = NULL;

		perf_event_release_kernel(event);

	}

}

#ifdef CONFIG_SYSCTL

/*

 * proc handler for /proc/sys/kernel/nmi_watchdog

 */

int nmi_watchdog_enabled;

int proc_nmi_enabled(struct ctl_table *table, int write,

		     void __user *buffer, size_t *length, loff_t *ppos)

{

	int cpu;

	if (!write) {

		struct perf_event *event;

		for_each_online_cpu(cpu) {

			event = per_cpu(nmi_watchdog_ev, cpu);

			if (event && event->state > PERF_EVENT_STATE_OFF) {

				nmi_watchdog_enabled = 1;

				break;

			}

		}

		proc_dointvec(table, write, buffer, length, ppos);

		return 0;

	}

	touch_all_nmi_watchdog();

	proc_dointvec(table, write, buffer, length, ppos);

	if (nmi_watchdog_enabled) {

		for_each_online_cpu(cpu)

			if (enable_nmi_watchdog(cpu)) {

				printk(KERN_ERR "NMI watchdog failed configuration, "

					" can not be enabled\n");

			}

	} else {

		for_each_online_cpu(cpu)

			disable_nmi_watchdog(cpu);

	}

	return 0;

}

#endif /* CONFIG_SYSCTL */

/*

 * Create/destroy watchdog threads as CPUs come and go:

 */

static int __cpuinit

cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)

{

	int hotcpu = (unsigned long)hcpu;

	switch (action) {

	case CPU_UP_PREPARE:

	case CPU_UP_PREPARE_FROZEN:

		per_cpu(nmi_watchdog_touch, hotcpu) = 0;

		break;

	case CPU_ONLINE:

	case CPU_ONLINE_FROZEN:

		if (enable_nmi_watchdog(hotcpu))

			return NOTIFY_BAD;

		break;

#ifdef CONFIG_HOTPLUG_CPU

	case CPU_UP_CANCELED:

	case CPU_UP_CANCELED_FROZEN:

		disable_nmi_watchdog(hotcpu);

	case CPU_DEAD:

	case CPU_DEAD_FROZEN:

		break;

#endif /* CONFIG_HOTPLUG_CPU */

	}

	return NOTIFY_OK;

}

static struct notifier_block __cpuinitdata cpu_nfb = {

	.notifier_call = cpu_callback

};

static int __initdata nonmi_watchdog;

static int __init nonmi_watchdog_setup(char *str)

{

	nonmi_watchdog = 1;

	return 1;

}

__setup("nonmi_watchdog", nonmi_watchdog_setup);

static int __init spawn_nmi_watchdog_task(void)

{

	void *cpu = (void *)(long)smp_processor_id();

	int err;

	if (nonmi_watchdog)

		return 0;

	printk(KERN_INFO "NMI watchdog enabled, takes one hw-pmu counter.\n");

	err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);

	if (err == NOTIFY_BAD) {

		BUG();

		return 1;

	}

	cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);

	register_cpu_notifier(&cpu_nfb);

	return 0;

}

early_initcall(spawn_nmi_watchdog_task);