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[/] [or1k_soc_on_altera_embedded_dev_kit/] [trunk/] [linux-2.6/] [linux-2.6.24/] [arch/] [x86/] [kernel/] [nmi_64.c] - Rev 3
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/* * 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(KERN_WARNING "WARNING: 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) + read_pda(irq0_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);