--- /dev/null
- prev_nmi_count = kmalloc(NR_CPUS * sizeof(int), GFP_KERNEL);
+ /*
+ * 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/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;
+
+ 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 */
+ EXPORT_SYMBOL(nmi_active);
+
+ unsigned int nmi_watchdog = NMI_DEFAULT;
+ 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)
+ {
+ if (nmi_watchdog != NMI_DEFAULT)
+ return;
+ nmi_watchdog = NMI_NONE;
+ }
+
+ #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_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, 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) {
+ printk(KERN_WARNING "WARNING: CPU#%d: NMI "
+ "appears to be stuck (%d->%d)!\n",
+ cpu,
+ prev_nmi_count[cpu],
+ get_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;
-#ifdef CONFIG_X86_32
- timer_ack = !cpu_has_tsc;
-#endif
+ error:
++ if (nmi_watchdog == NMI_IO_APIC && !timer_through_8259)
++ disable_8259A_irq(0);
+ return -1;
+ }
+
+ static 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);
+
+ /*
+ * 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_around(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:
+ /* 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;
+ 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 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 == NMI_LOCAL_APIC ||
+ nmi_watchdog == NMI_IO_APIC) {
+ 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;
+
+ /* check for other users first */
+ if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
+ == NOTIFY_STOP) {
+ rc = 1;
+ touched = 1;
+ }
+
+ sum = get_timer_irqs(cpu);
+
+ 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(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
+ dump_stack();
+ spin_unlock(&lock);
+ cpu_clear(cpu, backtrace_mask);
+ }
+
+ /* 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 ...
+ */
+ local_inc(&__get_cpu_var(alert_counter));
+ if (local_read(&__get_cpu_var(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;
+ 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;
+ }
+
+ #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();
+
+ #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();
+ else
+ disable_lapic_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 __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);
+ }
+ }
projects / linux-2.6-block.git / commitdiff