+++ /dev/null
-/*
- * 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);
- }
-}
projects / linux-beck.git / commitdiff