Merge branch 'x86/nmi' into x86/devel (4b62ac9a) · Commits · e / devices / android_kernel_xiaomi_markw

arch/x86/kernel/Makefile

+1 −1

Original line number	Diff line number	Diff line
		@@ -52,7 +52,7 @@ obj-$(CONFIG_X86_32_SMP) += smpcommon.o
		obj-$(CONFIG_X86_64_SMP) += tsc_sync.o smpcommon.o
		obj-$(CONFIG_X86_TRAMPOLINE) += trampoline_$(BITS).o
		obj-$(CONFIG_X86_MPPARSE) += mpparse.o
		obj-$(CONFIG_X86_LOCAL_APIC) += apic_$(BITS).o nmi_$(BITS).o
		obj-$(CONFIG_X86_LOCAL_APIC) += apic_$(BITS).o nmi.o
		obj-$(CONFIG_X86_IO_APIC) += io_apic_$(BITS).o
		obj-$(CONFIG_X86_REBOOTFIXUPS) += reboot_fixups_32.o
		obj-$(CONFIG_KEXEC) += machine_kexec_$(BITS).o

arch/x86/kernel/cpu/perfctr-watchdog.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -181,6 +181,8 @@ void disable_lapic_nmi_watchdog(void)
		return;

		on_each_cpu(stop_apic_nmi_watchdog, NULL, 0, 1);

		if (wd_ops)
		wd_ops->unreserve();

		BUG_ON(atomic_read(&nmi_active) != 0);

arch/x86/kernel/nmi_64.c→arch/x86/kernel/nmi.c

+128 −79

Original line number	Diff line number	Diff line
		@@ -6,10 +6,13 @@
		* Fixes:
		* Mikael Pettersson : AMD K7 support for local APIC NMI watchdog.
		* Mikael Pettersson : Power Management for local APIC NMI watchdog.
		* Mikael Pettersson : Pentium 4 support for local APIC NMI watchdog.
		* Pavel Machek and
		* Mikael Pettersson : PM converted to driver model. Disable/enable API.
		*/

		#include <asm/apic.h>

		#include <linux/nmi.h>
		#include <linux/mm.h>
		#include <linux/delay.h>
		@@ -17,22 +20,26 @@
		#include <linux/module.h>
		#include <linux/sysdev.h>
		#include <linux/sysctl.h>
		#include <linux/percpu.h>
		#include <linux/kprobes.h>
		#include <linux/cpumask.h>
		#include <linux/kernel_stat.h>
		#include <linux/kdebug.h>
		#include <linux/smp.h>

		#include <asm/i8259.h>
		#include <asm/io_apic.h>
		#include <asm/smp.h>
		#include <asm/nmi.h>
		#include <asm/proto.h>
		#include <asm/timer.h>

		#include <asm/mce.h>

		#include <mach_traps.h>

		int unknown_nmi_panic;
		int nmi_watchdog_enabled;
		int panic_on_unrecovered_nmi;

		static cpumask_t backtrace_mask = CPU_MASK_NONE;

		@@ -43,12 +50,47 @@ static cpumask_t backtrace_mask = CPU_MASK_NONE;
		* 0: the lapic NMI watchdog is disabled, but can be enabled
		*/
		atomic_t nmi_active = ATOMIC_INIT(0); /* oprofile uses this */
		static int panic_on_timeout;
		EXPORT_SYMBOL(nmi_active);

		unsigned int nmi_watchdog = NMI_DEFAULT;
		static unsigned int nmi_hz = HZ;
		EXPORT_SYMBOL(nmi_watchdog);

		static int panic_on_timeout;

		static unsigned int nmi_hz = HZ;
		static DEFINE_PER_CPU(short, wd_enabled);
		static int endflag __initdata;

		static inline unsigned int get_nmi_count(int cpu)
		{
		#ifdef CONFIG_X86_64
		return cpu_pda(cpu)->__nmi_count;
		#else
		return nmi_count(cpu);
		#endif
		}

		static inline int mce_in_progress(void)
		{
		#if defined(CONFIG_X86_64) && defined(CONFIG_X86_MCE)
		return atomic_read(&mce_entry) > 0;
		#endif
		return 0;
		}

		/*
		* Take the local apic timer and PIT/HPET into account. We don't
		* know which one is active, when we have highres/dyntick on
		*/
		static inline unsigned int get_timer_irqs(int cpu)
		{
		#ifdef CONFIG_X86_64
		return read_pda(apic_timer_irqs) + read_pda(irq0_irqs);
		#else
		return per_cpu(irq_stat, cpu).apic_timer_irqs +
		per_cpu(irq_stat, cpu).irq0_irqs;
		#endif
		}

		/* Run after command line and cpu_init init, but before all other checks */
		void nmi_watchdog_default(void)
		@@ -58,22 +100,23 @@ void nmi_watchdog_default(void)
		nmi_watchdog = NMI_NONE;
		}

		static int endflag __initdata = 0;

		#ifdef CONFIG_SMP
		/* The performance counters used by NMI_LOCAL_APIC don't trigger when
		/*
		* The performance counters used by NMI_LOCAL_APIC don't trigger when
		* the CPU is idle. To make sure the NMI watchdog really ticks on all
		* CPUs during the test make them busy.
		*/
		static __init void nmi_cpu_busy(void *data)
		{
		local_irq_enable_in_hardirq();
		/* Intentionally don't use cpu_relax here. This is
		to make sure that the performance counter really ticks,
		even if there is a simulator or similar that catches the
		pause instruction. On a real HT machine this is fine because
		all other CPUs are busy with "useless" delay loops and don't
		care if they get somewhat less cycles. */
		/*
		* Intentionally don't use cpu_relax here. This is
		* to make sure that the performance counter really ticks,
		* even if there is a simulator or similar that catches the
		* pause instruction. On a real HT machine this is fine because
		* all other CPUs are busy with "useless" delay loops and don't
		* care if they get somewhat less cycles.
		*/
		while (endflag == 0)
		mb();
		}
		@@ -81,10 +124,10 @@ static __init void nmi_cpu_busy(void *data)

		int __init check_nmi_watchdog(void)
		{
		int *prev_nmi_count;
		unsigned int *prev_nmi_count;
		int cpu;

		if ((nmi_watchdog == NMI_NONE) \|\| (nmi_watchdog == NMI_DISABLED))
		if (nmi_watchdog == NMI_NONE \|\| nmi_watchdog == NMI_DISABLED)
		return 0;

		if (!atomic_read(&nmi_active))
		@@ -101,20 +144,20 @@ int __init check_nmi_watchdog(void)
		smp_call_function(nmi_cpu_busy, (void *)&endflag, 0, 0);
		#endif

		for (cpu = 0; cpu < nr_cpu_ids; cpu++)
		prev_nmi_count[cpu] = cpu_pda(cpu)->__nmi_count;
		for_each_possible_cpu(cpu)
		prev_nmi_count[cpu] = get_nmi_count(cpu);
		local_irq_enable();
		mdelay((20*1000)/nmi_hz); // wait 20 ticks
		mdelay((20 * 1000) / nmi_hz); /* wait 20 ticks */

		for_each_online_cpu(cpu) {
		if (!per_cpu(wd_enabled, cpu))
		continue;
		if (cpu_pda(cpu)->__nmi_count - prev_nmi_count[cpu] <= 5) {
		if (get_nmi_count(cpu) - prev_nmi_count[cpu] <= 5) {
		printk(KERN_WARNING "WARNING: CPU#%d: NMI "
		"appears to be stuck (%d->%d)!\n",
		cpu,
		prev_nmi_count[cpu],
		cpu_pda(cpu)->__nmi_count);
		get_nmi_count(cpu));
		per_cpu(wd_enabled, cpu) = 0;
		atomic_dec(&nmi_active);
		}
		@@ -127,8 +170,10 @@ int __init check_nmi_watchdog(void)
		}
		printk("OK.\n");

		/* now that we know it works we can reduce NMI frequency to
		something more reasonable; makes a difference in some configs */
		/*
		* now that we know it works we can reduce NMI frequency to
		* something more reasonable; makes a difference in some configs
		*/
		if (nmi_watchdog == NMI_LOCAL_APIC)
		nmi_hz = lapic_adjust_nmi_hz(1);

		@@ -137,7 +182,6 @@ int __init check_nmi_watchdog(void)
		error:
		if (nmi_watchdog == NMI_IO_APIC && !timer_through_8259)
		disable_8259A_irq(0);

		return -1;
		}

		@@ -155,15 +199,17 @@ static int __init setup_nmi_watchdog(char *str)

		get_option(&str, &nmi);

		if ((nmi >= NMI_INVALID) \|\| (nmi < NMI_NONE))
		if (nmi >= NMI_INVALID \|\| nmi < NMI_NONE)
		return 0;

		nmi_watchdog = nmi;
		return 1;
		}

		__setup("nmi_watchdog=", setup_nmi_watchdog);

		/*
		* Suspend/resume support
		*/
		#ifdef CONFIG_PM

		static int nmi_pm_active; /* nmi_active before suspend */
		@@ -202,7 +248,8 @@ static int __init init_lapic_nmi_sysfs(void)
		{
		int error;

		/* should really be a BUG_ON but b/c this is an
		/*
		* should really be a BUG_ON but b/c this is an
		* init call, it just doesn't work. -dcz
		*/
		if (nmi_watchdog != NMI_LOCAL_APIC)
		@@ -216,6 +263,7 @@ static int __init init_lapic_nmi_sysfs(void)
		error = sysdev_register(&device_lapic_nmi);
		return error;
		}

		/* must come after the local APIC's device_initcall() */
		late_initcall(init_lapic_nmi_sysfs);

		@@ -223,7 +271,7 @@ late_initcall(init_lapic_nmi_sysfs);

		static void __acpi_nmi_enable(void *__unused)
		{
		apic_write(APIC_LVT0, APIC_DM_NMI);
		apic_write_around(APIC_LVT0, APIC_DM_NMI);
		}

		/*
		@@ -237,7 +285,7 @@ void acpi_nmi_enable(void)

		static void __acpi_nmi_disable(void *__unused)
		{
		apic_write(APIC_LVT0, APIC_DM_NMI \| APIC_LVT_MASKED);
		apic_write_around(APIC_LVT0, APIC_DM_NMI \| APIC_LVT_MASKED);
		}

		/*
		@@ -256,11 +304,12 @@ void setup_apic_nmi_watchdog(void *unused)

		/* cheap hack to support suspend/resume */
		/* if cpu0 is not active neither should the other cpus */
		if ((smp_processor_id() != 0) && (atomic_read(&nmi_active) <= 0))
		if (smp_processor_id() != 0 && atomic_read(&nmi_active) <= 0)
		return;

		switch (nmi_watchdog) {
		case NMI_LOCAL_APIC:
		/* enable it before to avoid race with handler */
		__get_cpu_var(wd_enabled) = 1;
		if (lapic_watchdog_init(nmi_hz) < 0) {
		__get_cpu_var(wd_enabled) = 0;
		@@ -276,8 +325,8 @@ void setup_apic_nmi_watchdog(void *unused)
		void stop_apic_nmi_watchdog(void *unused)
		{
		/* only support LOCAL and IO APICs for now */
		if ((nmi_watchdog != NMI_LOCAL_APIC) &&
		(nmi_watchdog != NMI_IO_APIC))
		if (nmi_watchdog != NMI_LOCAL_APIC &&
		nmi_watchdog != NMI_IO_APIC)
		return;
		if (__get_cpu_var(wd_enabled) == 0)
		return;
		@@ -294,6 +343,11 @@ void stop_apic_nmi_watchdog(void *unused)
		*
		* as these watchdog NMI IRQs are generated on every CPU, we only
		* have to check the current processor.
		*
		* since NMIs don't listen to _any_ locks, we have to be extremely
		* careful not to rely on unsafe variables. The printk might lock
		* up though, so we have to break up any console locks first ...
		* [when there will be more tty-related locks, break them up here too!]
		*/

		static DEFINE_PER_CPU(unsigned, last_irq_sum);
		@@ -302,7 +356,8 @@ static DEFINE_PER_CPU(int, nmi_touch);

		void touch_nmi_watchdog(void)
		{
		if (nmi_watchdog > 0) {
		if (nmi_watchdog == NMI_LOCAL_APIC \|\|
		nmi_watchdog == NMI_IO_APIC) {
		unsigned cpu;

		/*
		@@ -316,6 +371,9 @@ void touch_nmi_watchdog(void)
		}
		}

		/*
		* Tickle the softlockup detector too:
		*/
		touch_softlockup_watchdog();
		}
		EXPORT_SYMBOL(touch_nmi_watchdog);
		@@ -323,7 +381,12 @@ EXPORT_SYMBOL(touch_nmi_watchdog);
		notrace __kprobes int
		nmi_watchdog_tick(struct pt_regs *regs, unsigned reason)
		{
		int sum;
		/*
		* Since current_thread_info()-> is always on the stack, and we
		* always switch the stack NMI-atomically, it's safe to use
		* smp_processor_id().
		*/
		unsigned int sum;
		int touched = 0;
		int cpu = smp_processor_id();
		int rc = 0;
		@@ -335,7 +398,8 @@ nmi_watchdog_tick(struct pt_regs *regs, unsigned reason)
		touched = 1;
		}

		sum = read_pda(apic_timer_irqs) + read_pda(irq0_irqs);
		sum = get_timer_irqs(cpu);

		if (__get_cpu_var(nmi_touch)) {
		__get_cpu_var(nmi_touch) = 0;
		touched = 1;
		@@ -345,19 +409,17 @@ nmi_watchdog_tick(struct pt_regs *regs, unsigned reason)
		static DEFINE_SPINLOCK(lock); /* Serialise the printks */

		spin_lock(&lock);
		printk("NMI backtrace for cpu %d\n", cpu);
		printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
		dump_stack();
		spin_unlock(&lock);
		cpu_clear(cpu, backtrace_mask);
		}

		#ifdef CONFIG_X86_MCE
		/* Could check oops_in_progress here too, but it's safer
		not too */
		if (atomic_read(&mce_entry) > 0)
		/* Could check oops_in_progress here too, but it's safer not to */
		if (mce_in_progress())
		touched = 1;
		#endif
		/* if the apic timer isn't firing, this cpu isn't doing much */

		/* if the none of the timers isn't firing, this cpu isn't doing much */
		if (!touched && __get_cpu_var(last_irq_sum) == sum) {
		/*
		* Ayiee, looks like this CPU is stuck ...
		@@ -365,8 +427,11 @@ nmi_watchdog_tick(struct pt_regs *regs, unsigned reason)
		*/
		local_inc(&__get_cpu_var(alert_counter));
		if (local_read(&__get_cpu_var(alert_counter)) == 5 * nmi_hz)
		die_nmi("NMI Watchdog detected LOCKUP on CPU %d\n", regs,
		panic_on_timeout);
		/*
		* die_nmi will return ONLY if NOTIFY_STOP happens..
		*/
		die_nmi("BUG: NMI Watchdog detected LOCKUP",
		regs, panic_on_timeout);
		} else {
		__get_cpu_var(last_irq_sum) = sum;
		local_set(&__get_cpu_var(alert_counter), 0);
		@@ -380,7 +445,8 @@ nmi_watchdog_tick(struct pt_regs *regs, unsigned reason)
		rc \|= lapic_wd_event(nmi_hz);
		break;
		case NMI_IO_APIC:
		/* don't know how to accurately check for this.
		/*
		* don't know how to accurately check for this.
		* just assume it was a watchdog timer interrupt
		* This matches the old behaviour.
		*/
		@@ -390,30 +456,6 @@ nmi_watchdog_tick(struct pt_regs *regs, unsigned reason)
		return rc;
		}

		static unsigned ignore_nmis;

		asmlinkage notrace __kprobes void
		do_nmi(struct pt_regs *regs, long error_code)
		{
		nmi_enter();
		add_pda(__nmi_count,1);
		if (!ignore_nmis)
		default_do_nmi(regs);
		nmi_exit();
		}

		void stop_nmi(void)
		{
		acpi_nmi_disable();
		ignore_nmis++;
		}

		void restart_nmi(void)
		{
		ignore_nmis--;
		acpi_nmi_enable();
		}

		#ifdef CONFIG_SYSCTL

		static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu)
		@@ -441,13 +483,23 @@ int proc_nmi_enabled(struct ctl_table table, int write, struct file file,
		return 0;

		if (atomic_read(&nmi_active) < 0 \|\| nmi_watchdog == NMI_DISABLED) {
		printk( KERN_WARNING "NMI watchdog is permanently disabled\n");
		printk(KERN_WARNING
		"NMI watchdog is permanently disabled\n");
		return -EIO;
		}

		/* if nmi_watchdog is not set yet, then set it */
		nmi_watchdog_default();

		#ifdef CONFIG_X86_32
		if (nmi_watchdog == NMI_NONE) {
		if (lapic_watchdog_ok())
		nmi_watchdog = NMI_LOCAL_APIC;
		else
		nmi_watchdog = NMI_IO_APIC;
		}
		#endif

		if (nmi_watchdog == NMI_LOCAL_APIC) {
		if (nmi_watchdog_enabled)
		enable_lapic_nmi_watchdog();
		@@ -461,7 +513,7 @@ int proc_nmi_enabled(struct ctl_table table, int write, struct file file,
		return 0;
		}

		#endif
		#endif /* CONFIG_SYSCTL */

		int do_nmi_callback(struct pt_regs *regs, int cpu)
		{
		@@ -484,6 +536,3 @@ void __trigger_all_cpu_backtrace(void)
		mdelay(1);
		}
		}

		EXPORT_SYMBOL(nmi_active);
		EXPORT_SYMBOL(nmi_watchdog);

arch/x86/kernel/nmi_32.c

deleted100644 → 0

+0 −476

Original line number	Diff line number	Diff line
		/*
		* NMI watchdog support on APIC systems
		*
		* Started by Ingo Molnar <mingo@redhat.com>
		*
		* Fixes:
		* Mikael Pettersson : AMD K7 support for local APIC NMI watchdog.
		* Mikael Pettersson : Power Management for local APIC NMI watchdog.
		* Mikael Pettersson : Pentium 4 support for local APIC NMI watchdog.
		* Pavel Machek and
		* Mikael Pettersson : PM converted to driver model. Disable/enable API.
		*/

		#include <linux/delay.h>
		#include <linux/interrupt.h>
		#include <linux/module.h>
		#include <linux/nmi.h>
		#include <linux/sysdev.h>
		#include <linux/sysctl.h>
		#include <linux/percpu.h>
		#include <linux/kprobes.h>
		#include <linux/cpumask.h>
		#include <linux/kernel_stat.h>
		#include <linux/kdebug.h>
		#include <linux/slab.h>

		#include <asm/i8259.h>
		#include <asm/io_apic.h>
		#include <asm/smp.h>
		#include <asm/nmi.h>
		#include <asm/timer.h>

		#include "mach_traps.h"

		int unknown_nmi_panic;
		int nmi_watchdog_enabled;

		static cpumask_t backtrace_mask = CPU_MASK_NONE;

		/* nmi_active:
		* >0: the lapic NMI watchdog is active, but can be disabled
		* <0: the lapic NMI watchdog has not been set up, and cannot
		* be enabled
		* 0: the lapic NMI watchdog is disabled, but can be enabled
		*/
		atomic_t nmi_active = ATOMIC_INIT(0); /* oprofile uses this */

		unsigned int nmi_watchdog = NMI_DEFAULT;
		static unsigned int nmi_hz = HZ;

		static DEFINE_PER_CPU(short, wd_enabled);

		static int endflag __initdata = 0;

		#ifdef CONFIG_SMP
		/* The performance counters used by NMI_LOCAL_APIC don't trigger when
		* the CPU is idle. To make sure the NMI watchdog really ticks on all
		* CPUs during the test make them busy.
		*/
		static __init void nmi_cpu_busy(void *data)
		{
		local_irq_enable_in_hardirq();
		/* Intentionally don't use cpu_relax here. This is
		to make sure that the performance counter really ticks,
		even if there is a simulator or similar that catches the
		pause instruction. On a real HT machine this is fine because
		all other CPUs are busy with "useless" delay loops and don't
		care if they get somewhat less cycles. */
		while (endflag == 0)
		mb();
		}
		#endif

		int __init check_nmi_watchdog(void)
		{
		unsigned int *prev_nmi_count;
		int cpu;

		if ((nmi_watchdog == NMI_NONE) \|\| (nmi_watchdog == NMI_DISABLED))
		return 0;

		if (!atomic_read(&nmi_active))
		return 0;

		prev_nmi_count = kmalloc(NR_CPUS * sizeof(int), GFP_KERNEL);
		if (!prev_nmi_count)
		goto error;

		printk(KERN_INFO "Testing NMI watchdog ... ");

		#ifdef CONFIG_SMP
		if (nmi_watchdog == NMI_LOCAL_APIC)
		smp_call_function(nmi_cpu_busy, (void *)&endflag, 0, 0);
		#endif

		for_each_possible_cpu(cpu)
		prev_nmi_count[cpu] = nmi_count(cpu);
		local_irq_enable();
		mdelay((20*1000)/nmi_hz); // wait 20 ticks

		for_each_possible_cpu(cpu) {
		#ifdef CONFIG_SMP
		/* Check cpu_callin_map here because that is set
		after the timer is started. */
		if (!cpu_isset(cpu, cpu_callin_map))
		continue;
		#endif
		if (!per_cpu(wd_enabled, cpu))
		continue;
		if (nmi_count(cpu) - prev_nmi_count[cpu] <= 5) {
		printk(KERN_WARNING "WARNING: CPU#%d: NMI "
		"appears to be stuck (%d->%d)!\n",
		cpu,
		prev_nmi_count[cpu],
		nmi_count(cpu));
		per_cpu(wd_enabled, cpu) = 0;
		atomic_dec(&nmi_active);
		}
		}
		endflag = 1;
		if (!atomic_read(&nmi_active)) {
		kfree(prev_nmi_count);
		atomic_set(&nmi_active, -1);
		goto error;
		}
		printk("OK.\n");

		/* now that we know it works we can reduce NMI frequency to
		something more reasonable; makes a difference in some configs */
		if (nmi_watchdog == NMI_LOCAL_APIC)
		nmi_hz = lapic_adjust_nmi_hz(1);

		kfree(prev_nmi_count);
		return 0;
		error:
		if (nmi_watchdog == NMI_IO_APIC && !timer_through_8259)
		disable_8259A_irq(0);
		timer_ack = 0;

		return -1;
		}

		static int __init setup_nmi_watchdog(char *str)
		{
		int nmi;

		get_option(&str, &nmi);

		if ((nmi >= NMI_INVALID) \|\| (nmi < NMI_NONE))
		return 0;

		nmi_watchdog = nmi;
		return 1;
		}

		__setup("nmi_watchdog=", setup_nmi_watchdog);


		/* Suspend/resume support */

		#ifdef CONFIG_PM

		static int nmi_pm_active; /* nmi_active before suspend */

		static int lapic_nmi_suspend(struct sys_device *dev, pm_message_t state)
		{
		/* only CPU0 goes here, other CPUs should be offline */
		nmi_pm_active = atomic_read(&nmi_active);
		stop_apic_nmi_watchdog(NULL);
		BUG_ON(atomic_read(&nmi_active) != 0);
		return 0;
		}

		static int lapic_nmi_resume(struct sys_device *dev)
		{
		/* only CPU0 goes here, other CPUs should be offline */
		if (nmi_pm_active > 0) {
		setup_apic_nmi_watchdog(NULL);
		touch_nmi_watchdog();
		}
		return 0;
		}


		static struct sysdev_class nmi_sysclass = {
		.name = "lapic_nmi",
		.resume = lapic_nmi_resume,
		.suspend = lapic_nmi_suspend,
		};

		static struct sys_device device_lapic_nmi = {
		.id = 0,
		.cls = &nmi_sysclass,
		};

		static int __init init_lapic_nmi_sysfs(void)
		{
		int error;

		/* should really be a BUG_ON but b/c this is an
		* init call, it just doesn't work. -dcz
		*/
		if (nmi_watchdog != NMI_LOCAL_APIC)
		return 0;

		if (atomic_read(&nmi_active) < 0)
		return 0;

		error = sysdev_class_register(&nmi_sysclass);
		if (!error)
		error = sysdev_register(&device_lapic_nmi);
		return error;
		}
		/* must come after the local APIC's device_initcall() */
		late_initcall(init_lapic_nmi_sysfs);

		#endif /* CONFIG_PM */

		static void __acpi_nmi_enable(void *__unused)
		{
		apic_write_around(APIC_LVT0, APIC_DM_NMI);
		}

		/*
		* Enable timer based NMIs on all CPUs:
		*/
		void acpi_nmi_enable(void)
		{
		if (atomic_read(&nmi_active) && nmi_watchdog == NMI_IO_APIC)
		on_each_cpu(__acpi_nmi_enable, NULL, 0, 1);
		}

		static void __acpi_nmi_disable(void *__unused)
		{
		apic_write(APIC_LVT0, APIC_DM_NMI \| APIC_LVT_MASKED);
		}

		/*
		* Disable timer based NMIs on all CPUs:
		*/
		void acpi_nmi_disable(void)
		{
		if (atomic_read(&nmi_active) && nmi_watchdog == NMI_IO_APIC)
		on_each_cpu(__acpi_nmi_disable, NULL, 0, 1);
		}

		void setup_apic_nmi_watchdog(void *unused)
		{
		if (__get_cpu_var(wd_enabled))
		return;

		/* cheap hack to support suspend/resume */
		/* if cpu0 is not active neither should the other cpus */
		if ((smp_processor_id() != 0) && (atomic_read(&nmi_active) <= 0))
		return;

		switch (nmi_watchdog) {
		case NMI_LOCAL_APIC:
		__get_cpu_var(wd_enabled) = 1; /* enable it before to avoid race with handler */
		if (lapic_watchdog_init(nmi_hz) < 0) {
		__get_cpu_var(wd_enabled) = 0;
		return;
		}
		/* FALL THROUGH */
		case NMI_IO_APIC:
		__get_cpu_var(wd_enabled) = 1;
		atomic_inc(&nmi_active);
		}
		}

		void stop_apic_nmi_watchdog(void *unused)
		{
		/* only support LOCAL and IO APICs for now */
		if ((nmi_watchdog != NMI_LOCAL_APIC) &&
		(nmi_watchdog != NMI_IO_APIC))
		return;
		if (__get_cpu_var(wd_enabled) == 0)
		return;
		if (nmi_watchdog == NMI_LOCAL_APIC)
		lapic_watchdog_stop();
		__get_cpu_var(wd_enabled) = 0;
		atomic_dec(&nmi_active);
		}

		/*
		* the best way to detect whether a CPU has a 'hard lockup' problem
		* is to check it's local APIC timer IRQ counts. If they are not
		* changing then that CPU has some problem.
		*
		* as these watchdog NMI IRQs are generated on every CPU, we only
		* have to check the current processor.
		*
		* since NMIs don't listen to _any_ locks, we have to be extremely
		* careful not to rely on unsafe variables. The printk might lock
		* up though, so we have to break up any console locks first ...
		* [when there will be more tty-related locks, break them up
		* here too!]
		*/

		static unsigned int
		last_irq_sums [NR_CPUS],
		alert_counter [NR_CPUS];

		void touch_nmi_watchdog(void)
		{
		if (nmi_watchdog > 0) {
		unsigned cpu;

		/*
		* Just reset the alert counters, (other CPUs might be
		* spinning on locks we hold):
		*/
		for_each_present_cpu(cpu) {
		if (alert_counter[cpu])
		alert_counter[cpu] = 0;
		}
		}

		/*
		* Tickle the softlockup detector too:
		*/
		touch_softlockup_watchdog();
		}
		EXPORT_SYMBOL(touch_nmi_watchdog);

		extern void die_nmi(struct pt_regs , const char msg);

		notrace __kprobes int
		nmi_watchdog_tick(struct pt_regs *regs, unsigned reason)
		{

		/*
		* Since current_thread_info()-> is always on the stack, and we
		* always switch the stack NMI-atomically, it's safe to use
		* smp_processor_id().
		*/
		unsigned int sum;
		int touched = 0;
		int cpu = smp_processor_id();
		int rc = 0;

		/* check for other users first */
		if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
		== NOTIFY_STOP) {
		rc = 1;
		touched = 1;
		}

		if (cpu_isset(cpu, backtrace_mask)) {
		static DEFINE_SPINLOCK(lock); /* Serialise the printks */

		spin_lock(&lock);
		printk("NMI backtrace for cpu %d\n", cpu);
		dump_stack();
		spin_unlock(&lock);
		cpu_clear(cpu, backtrace_mask);
		}

		/*
		* Take the local apic timer and PIT/HPET into account. We don't
		* know which one is active, when we have highres/dyntick on
		*/
		sum = per_cpu(irq_stat, cpu).apic_timer_irqs +
		per_cpu(irq_stat, cpu).irq0_irqs;

		/* if the none of the timers isn't firing, this cpu isn't doing much */
		if (!touched && last_irq_sums[cpu] == sum) {
		/*
		* Ayiee, looks like this CPU is stuck ...
		* wait a few IRQs (5 seconds) before doing the oops ...
		*/
		alert_counter[cpu]++;
		if (alert_counter[cpu] == 5*nmi_hz)
		/*
		* die_nmi will return ONLY if NOTIFY_STOP happens..
		*/
		die_nmi(regs, "BUG: NMI Watchdog detected LOCKUP");
		} else {
		last_irq_sums[cpu] = sum;
		alert_counter[cpu] = 0;
		}
		/* see if the nmi watchdog went off */
		if (!__get_cpu_var(wd_enabled))
		return rc;
		switch (nmi_watchdog) {
		case NMI_LOCAL_APIC:
		rc \|= lapic_wd_event(nmi_hz);
		break;
		case NMI_IO_APIC:
		/* don't know how to accurately check for this.
		* just assume it was a watchdog timer interrupt
		* This matches the old behaviour.
		*/
		rc = 1;
		break;
		}
		return rc;
		}

		#ifdef CONFIG_SYSCTL

		static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu)
		{
		unsigned char reason = get_nmi_reason();
		char buf[64];

		sprintf(buf, "NMI received for unknown reason %02x\n", reason);
		die_nmi(regs, buf);
		return 0;
		}

		/*
		* proc handler for /proc/sys/kernel/nmi
		*/
		int proc_nmi_enabled(struct ctl_table table, int write, struct file file,
		void __user buffer, size_t length, loff_t *ppos)
		{
		int old_state;

		nmi_watchdog_enabled = (atomic_read(&nmi_active) > 0) ? 1 : 0;
		old_state = nmi_watchdog_enabled;
		proc_dointvec(table, write, file, buffer, length, ppos);
		if (!!old_state == !!nmi_watchdog_enabled)
		return 0;

		if (atomic_read(&nmi_active) < 0 \|\| nmi_watchdog == NMI_DISABLED) {
		printk( KERN_WARNING "NMI watchdog is permanently disabled\n");
		return -EIO;
		}

		if (nmi_watchdog == NMI_DEFAULT) {
		if (lapic_watchdog_ok())
		nmi_watchdog = NMI_LOCAL_APIC;
		else
		nmi_watchdog = NMI_IO_APIC;
		}

		if (nmi_watchdog == NMI_LOCAL_APIC) {
		if (nmi_watchdog_enabled)
		enable_lapic_nmi_watchdog();
		else
		disable_lapic_nmi_watchdog();
		} else {
		printk( KERN_WARNING
		"NMI watchdog doesn't know what hardware to touch\n");
		return -EIO;
		}
		return 0;
		}

		#endif

		int do_nmi_callback(struct pt_regs *regs, int cpu)
		{
		#ifdef CONFIG_SYSCTL
		if (unknown_nmi_panic)
		return unknown_nmi_panic_callback(regs, cpu);
		#endif
		return 0;
		}

		void __trigger_all_cpu_backtrace(void)
		{
		int i;

		backtrace_mask = cpu_online_map;
		/* Wait for up to 10 seconds for all CPUs to do the backtrace */
		for (i = 0; i < 10 * 1000; i++) {
		if (cpus_empty(backtrace_mask))
		break;
		mdelay(1);
		}
		}

		EXPORT_SYMBOL(nmi_active);
		EXPORT_SYMBOL(nmi_watchdog);

arch/x86/kernel/traps_32.c

+5 −3

Original line number	Diff line number	Diff line
		@@ -756,9 +756,9 @@ unknown_nmi_error(unsigned char reason, struct pt_regs *regs)

		static DEFINE_SPINLOCK(nmi_print_lock);

		void notrace __kprobes die_nmi(struct pt_regs regs, const char msg)
		void notrace __kprobes die_nmi(char str, struct pt_regs regs, int do_panic)
		{
		if (notify_die(DIE_NMIWATCHDOG, msg, regs, 0, 2, SIGINT) == NOTIFY_STOP)
		if (notify_die(DIE_NMIWATCHDOG, str, regs, 0, 2, SIGINT) == NOTIFY_STOP)
		return;

		spin_lock(&nmi_print_lock);
		@@ -767,10 +767,12 @@ void notrace __kprobes die_nmi(struct pt_regs regs, const char msg)
		* to get a message out:
		*/
		bust_spinlocks(1);
		printk(KERN_EMERG "%s", msg);
		printk(KERN_EMERG "%s", str);
		printk(" on CPU%d, ip %08lx, registers:\n",
		smp_processor_id(), regs->ip);
		show_registers(regs);
		if (do_panic)
		panic("Non maskable interrupt");
		console_silent();
		spin_unlock(&nmi_print_lock);
		bust_spinlocks(0);