+++ /dev/null
-/*
- * linux/arch/x86_64/nmi.c
- *
- * 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.
- * Pavel Machek and
- * Mikael Pettersson : PM converted to driver model. Disable/enable API.
- */
-
-#include <linux/nmi.h>
-#include <linux/mm.h>
-#include <linux/delay.h>
-#include <linux/interrupt.h>
-#include <linux/module.h>
-#include <linux/sysdev.h>
-#include <linux/sysctl.h>
-#include <linux/kprobes.h>
-#include <linux/cpumask.h>
-#include <linux/kdebug.h>
-
-#include <asm/smp.h>
-#include <asm/nmi.h>
-#include <asm/proto.h>
-#include <asm/mce.h>
-
-int unknown_nmi_panic;
-int nmi_watchdog_enabled;
-int panic_on_unrecovered_nmi;
-
-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 */
-int panic_on_timeout;
-
-unsigned int nmi_watchdog = NMI_DEFAULT;
-static unsigned int nmi_hz = HZ;
-
-static DEFINE_PER_CPU(short, wd_enabled);
-
-/* local prototypes */
-static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu);
-
-/* Run after command line and cpu_init init, but before all other checks */
-void nmi_watchdog_default(void)
-{
- if (nmi_watchdog != NMI_DEFAULT)
- return;
- 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 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)
-{
- int *counts;
- int cpu;
-
- if ((nmi_watchdog == NMI_NONE) || (nmi_watchdog == NMI_DISABLED))
- return 0;
-
- if (!atomic_read(&nmi_active))
- return 0;
-
- counts = kmalloc(NR_CPUS * sizeof(int), GFP_KERNEL);
- if (!counts)
- return -1;
-
- 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 (cpu = 0; cpu < NR_CPUS; cpu++)
- counts[cpu] = cpu_pda(cpu)->__nmi_count;
- local_irq_enable();
- 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 - counts[cpu] <= 5) {
- printk("CPU#%d: NMI appears to be stuck (%d->%d)!\n",
- cpu,
- counts[cpu],
- cpu_pda(cpu)->__nmi_count);
- per_cpu(wd_enabled, cpu) = 0;
- atomic_dec(&nmi_active);
- }
- }
- if (!atomic_read(&nmi_active)) {
- kfree(counts);
- atomic_set(&nmi_active, -1);
- endflag = 1;
- return -1;
- }
- endflag = 1;
- 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(counts);
- return 0;
-}
-
-int __init setup_nmi_watchdog(char *str)
-{
- int nmi;
-
- if (!strncmp(str,"panic",5)) {
- panic_on_timeout = 1;
- str = strchr(str, ',');
- if (!str)
- return 1;
- ++str;
- }
-
- get_option(&str, &nmi);
-
- if ((nmi >= NMI_INVALID) || (nmi < NMI_NONE))
- return 0;
-
- nmi_watchdog = nmi;
- return 1;
-}
-
-__setup("nmi_watchdog=", setup_nmi_watchdog);
-
-
-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);
-}
-
-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, 0, 1);
-}
-#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 = {
- set_kset_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 */
-
-void setup_apic_nmi_watchdog(void *unused)
-{
- if (__get_cpu_var(wd_enabled) == 1)
- 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;
- 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.
- */
-
-static DEFINE_PER_CPU(unsigned, last_irq_sum);
-static DEFINE_PER_CPU(local_t, alert_counter);
-static DEFINE_PER_CPU(int, nmi_touch);
-
-void touch_nmi_watchdog(void)
-{
- if (nmi_watchdog > 0) {
- 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;
- }
- }
-
- touch_softlockup_watchdog();
-}
-
-int __kprobes nmi_watchdog_tick(struct pt_regs * regs, unsigned reason)
-{
- 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;
- }
-
- sum = read_pda(apic_timer_irqs);
- if (__get_cpu_var(nmi_touch)) {
- __get_cpu_var(nmi_touch) = 0;
- 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);
- }
-
-#ifdef CONFIG_X86_MCE
- /* Could check oops_in_progress here too, but it's safer
- not too */
- if (atomic_read(&mce_entry) > 0)
- touched = 1;
-#endif
- /* if the apic timer 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 ...
- */
- 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);
- } else {
- __get_cpu_var(last_irq_sum) = sum;
- local_set(&__get_cpu_var(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;
-}
-
-static unsigned ignore_nmis;
-
-asmlinkage __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();
-}
-
-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 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)
-{
- 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, 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 is not set yet, then set it */
- nmi_watchdog_default();
-
- 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
-
-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);
-EXPORT_SYMBOL(touch_nmi_watchdog);
git.openpandora.org / pandora-kernel.git / blobdiff