x86, nmi_watchdog: Remove the old nmi_watchdog (5f2b0ba4) · Commits · 戴 / test

arch/x86/include/asm/nmi.h

+0 −4

Original line number	Diff line number	Diff line
		@@ -17,9 +17,6 @@ int do_nmi_callback(struct pt_regs *regs, int cpu);

		extern void die_nmi(char str, struct pt_regs regs, int do_panic);
		extern int check_nmi_watchdog(void);
		#if !defined(CONFIG_LOCKUP_DETECTOR)
		extern int nmi_watchdog_enabled;
		#endif
		extern int avail_to_resrv_perfctr_nmi_bit(unsigned int);
		extern int reserve_perfctr_nmi(unsigned int);
		extern void release_perfctr_nmi(unsigned int);
		@@ -30,7 +27,6 @@ extern void setup_apic_nmi_watchdog(void *);
		extern void stop_apic_nmi_watchdog(void *);
		extern void disable_timer_nmi_watchdog(void);
		extern void enable_timer_nmi_watchdog(void);
		extern int nmi_watchdog_tick(struct pt_regs *regs, unsigned reason);
		extern void cpu_nmi_set_wd_enabled(void);

		extern atomic_t nmi_active;

arch/x86/kernel/apic/Makefile

+1 −4

Original line number	Diff line number	Diff line
		@@ -3,10 +3,7 @@
		#

		obj-$(CONFIG_X86_LOCAL_APIC) += apic.o apic_noop.o probe_$(BITS).o ipi.o
		ifneq ($(CONFIG_HARDLOCKUP_DETECTOR),y)
		obj-$(CONFIG_X86_LOCAL_APIC) += nmi.o
		endif
		obj-$(CONFIG_HARDLOCKUP_DETECTOR) += hw_nmi.o
		obj-y += hw_nmi.o

		obj-$(CONFIG_X86_IO_APIC) += io_apic.o
		obj-$(CONFIG_SMP) += ipi.o

arch/x86/kernel/apic/hw_nmi.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -20,12 +20,14 @@
		/* For reliability, we're prepared to waste bits here. */
		static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;

		#ifdef CONFIG_HARDLOCKUP_DETECTOR
		u64 hw_nmi_get_sample_period(void)
		{
		return (u64)(cpu_khz) * 1000 * 60;
		}
		#endif

		#ifdef ARCH_HAS_NMI_WATCHDOG
		#ifdef arch_trigger_all_cpu_backtrace
		void arch_trigger_all_cpu_backtrace(void)
		{
		int i;
		@@ -95,8 +97,6 @@ early_initcall(register_trigger_all_cpu_backtrace);
		#if defined(CONFIG_X86_LOCAL_APIC)
		unsigned int nmi_watchdog = NMI_NONE;
		EXPORT_SYMBOL(nmi_watchdog);
		void acpi_nmi_enable(void) { return; }
		void acpi_nmi_disable(void) { return; }
		#endif
		atomic_t nmi_active = ATOMIC_INIT(0); /* oprofile uses this */
		EXPORT_SYMBOL(nmi_active);

arch/x86/kernel/apic/nmi.c

deleted100644 → 0

+0 −567

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 <asm/apic.h>

		#include <linux/nmi.h>
		#include <linux/mm.h>
		#include <linux/delay.h>
		#include <linux/interrupt.h>
		#include <linux/module.h>
		#include <linux/slab.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/proto.h>
		#include <asm/timer.h>

		#include <asm/mce.h>

		#include <asm/mach_traps.h>

		int unknown_nmi_panic;
		int nmi_watchdog_enabled;

		/* For reliability, we're prepared to waste bits here. */
		static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;

		/* 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 */
		EXPORT_SYMBOL(nmi_active);

		unsigned int nmi_watchdog = NMI_NONE;
		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)
		{
		return per_cpu(irq_stat, cpu).__nmi_count;
		}

		static inline int mce_in_progress(void)
		{
		#if 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)
		{
		return per_cpu(irq_stat, cpu).apic_timer_irqs +
		per_cpu(irq_stat, cpu).irq0_irqs;
		}

		#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

		static void report_broken_nmi(int cpu, unsigned int *prev_nmi_count)
		{
		printk(KERN_CONT "\n");

		printk(KERN_WARNING
		"WARNING: CPU#%d: NMI appears to be stuck (%d->%d)!\n",
		cpu, prev_nmi_count[cpu], get_nmi_count(cpu));

		printk(KERN_WARNING
		"Please report this to bugzilla.kernel.org,\n");
		printk(KERN_WARNING
		"and attach the output of the 'dmesg' command.\n");

		per_cpu(wd_enabled, cpu) = 0;
		atomic_dec(&nmi_active);
		}

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

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

		if (!nmi_watchdog_active() \|\| !atomic_read(&nmi_active))
		return 0;

		prev_nmi_count = kmalloc(nr_cpu_ids * 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);
		#endif

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

		for_each_online_cpu(cpu) {
		if (!per_cpu(wd_enabled, cpu))
		continue;
		if (get_nmi_count(cpu) - prev_nmi_count[cpu] <= 5)
		report_broken_nmi(cpu, prev_nmi_count);
		}
		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) {
		if (!timer_through_8259)
		legacy_pic->mask(0);
		on_each_cpu(__acpi_nmi_disable, NULL, 1);
		}

		#ifdef CONFIG_X86_32
		timer_ack = 0;
		#endif
		return -1;
		}

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

		if (!strncmp(str, "panic", 5)) {
		panic_on_timeout = 1;
		str = strchr(str, ',');
		if (!str)
		return 1;
		++str;
		}

		if (!strncmp(str, "lapic", 5))
		nmi_watchdog = NMI_LOCAL_APIC;
		else if (!strncmp(str, "ioapic", 6))
		nmi_watchdog = NMI_IO_APIC;
		else {
		get_option(&str, &nmi);
		if (nmi >= NMI_INVALID)
		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(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, 1);
		}

		/*
		* 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, 1);
		}

		/*
		* This function is called as soon the LAPIC NMI watchdog driver has everything
		* in place and it's ready to check if the NMIs belong to the NMI watchdog
		*/
		void cpu_nmi_set_wd_enabled(void)
		{
		__get_cpu_var(wd_enabled) = 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:
		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_active())
		return;
		if (__get_cpu_var(wd_enabled) == 0)
		return;
		if (nmi_watchdog == NMI_LOCAL_APIC)
		lapic_watchdog_stop();
		else
		__acpi_nmi_disable(NULL);
		__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 DEFINE_PER_CPU(unsigned, last_irq_sum);
		static DEFINE_PER_CPU(long, alert_counter);
		static DEFINE_PER_CPU(int, nmi_touch);

		void touch_nmi_watchdog(void)
		{
		if (nmi_watchdog_active()) {
		unsigned cpu;

		/*
		* Tell other CPUs to reset their alert counters. We cannot
		* do it ourselves because the alert count increase is not
		* atomic.
		*/
		for_each_present_cpu(cpu) {
		if (per_cpu(nmi_touch, cpu) != 1)
		per_cpu(nmi_touch, cpu) = 1;
		}
		}

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

		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;

		sum = get_timer_irqs(cpu);

		if (__get_cpu_var(nmi_touch)) {
		__get_cpu_var(nmi_touch) = 0;
		touched = 1;
		}

		/* We can be called before check_nmi_watchdog, hence NULL check. */
		if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
		static DEFINE_RAW_SPINLOCK(lock); /* Serialise the printks */

		raw_spin_lock(&lock);
		printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
		show_regs(regs);
		dump_stack();
		raw_spin_unlock(&lock);
		cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));

		rc = 1;
		}

		/* Could check oops_in_progress here too, but it's safer not to */
		if (mce_in_progress())
		touched = 1;

		/* 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 ...
		* wait a few IRQs (5 seconds) before doing the oops ...
		*/
		__this_cpu_inc(alert_counter);
		if (__this_cpu_read(alert_counter) == 5 * nmi_hz)
		/*
		* 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;
		__this_cpu_write(alert_counter, 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 void enable_ioapic_nmi_watchdog_single(void *unused)
		{
		__get_cpu_var(wd_enabled) = 1;
		atomic_inc(&nmi_active);
		__acpi_nmi_enable(NULL);
		}

		static void enable_ioapic_nmi_watchdog(void)
		{
		on_each_cpu(enable_ioapic_nmi_watchdog_single, NULL, 1);
		touch_nmi_watchdog();
		}

		static void disable_ioapic_nmi_watchdog(void)
		{
		on_each_cpu(stop_apic_nmi_watchdog, NULL, 1);
		}

		static int __init setup_unknown_nmi_panic(char *str)
		{
		unknown_nmi_panic = 1;
		return 1;
		}
		__setup("unknown_nmi_panic", setup_unknown_nmi_panic);

		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(buf, regs, 1); /* Always panic here */
		return 0;
		}

		/*
		* proc handler for /proc/sys/kernel/nmi
		*/
		int proc_nmi_enabled(struct ctl_table *table, int write,
		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, buffer, length, ppos);
		if (!!old_state == !!nmi_watchdog_enabled)
		return 0;

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

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

		#endif /* CONFIG_SYSCTL */

		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 arch_trigger_all_cpu_backtrace(void)
		{
		int i;

		cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask);

		printk(KERN_INFO "sending NMI to all CPUs:\n");
		apic->send_IPI_all(NMI_VECTOR);

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

arch/x86/kernel/traps.c

+0 −9

Original line number	Diff line number	Diff line
		@@ -398,15 +398,6 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
		== NOTIFY_STOP)
		return;

		#ifndef CONFIG_LOCKUP_DETECTOR
		/*
		* Ok, so this is none of the documented NMI sources,
		* so it must be the NMI watchdog.
		*/
		if (nmi_watchdog_tick(regs, reason))
		return;
		if (!do_nmi_callback(regs, cpu))
		#endif /* !CONFIG_LOCKUP_DETECTOR */
		unknown_nmi_error(reason, regs);
		#else
		unknown_nmi_error(reason, regs);

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