/* * linux/arch/x86_64/nmi.c * * NMI watchdog support on APIC systems * * Started by Ingo Molnar * * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include int unknown_nmi_panic; int nmi_watchdog_enabled; int panic_on_unrecovered_nmi; /* perfctr_nmi_owner tracks the ownership of the perfctr registers: * evtsel_nmi_owner tracks the ownership of the event selection * - different performance counters/ event selection may be reserved for * different subsystems this reservation system just tries to coordinate * things a little */ static DEFINE_PER_CPU(unsigned, perfctr_nmi_owner); static DEFINE_PER_CPU(unsigned, evntsel_nmi_owner[2]); static cpumask_t backtrace_mask = CPU_MASK_NONE; /* this number is calculated from Intel's MSR_P4_CRU_ESCR5 register and it's * offset from MSR_P4_BSU_ESCR0. It will be the max for all platforms (for now) */ #define NMI_MAX_COUNTER_BITS 66 /* 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; struct nmi_watchdog_ctlblk { int enabled; u64 check_bit; unsigned int cccr_msr; unsigned int perfctr_msr; /* the MSR to reset in NMI handler */ unsigned int evntsel_msr; /* the MSR to select the events to handle */ }; static DEFINE_PER_CPU(struct nmi_watchdog_ctlblk, nmi_watchdog_ctlblk); /* local prototypes */ static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu); /* converts an msr to an appropriate reservation bit */ static inline unsigned int nmi_perfctr_msr_to_bit(unsigned int msr) { /* returns the bit offset of the performance counter register */ switch (boot_cpu_data.x86_vendor) { case X86_VENDOR_AMD: return (msr - MSR_K7_PERFCTR0); case X86_VENDOR_INTEL: if (cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON)) return (msr - MSR_ARCH_PERFMON_PERFCTR0); else return (msr - MSR_P4_BPU_PERFCTR0); } return 0; } /* converts an msr to an appropriate reservation bit */ static inline unsigned int nmi_evntsel_msr_to_bit(unsigned int msr) { /* returns the bit offset of the event selection register */ switch (boot_cpu_data.x86_vendor) { case X86_VENDOR_AMD: return (msr - MSR_K7_EVNTSEL0); case X86_VENDOR_INTEL: if (cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON)) return (msr - MSR_ARCH_PERFMON_EVENTSEL0); else return (msr - MSR_P4_BSU_ESCR0); } return 0; } /* checks for a bit availability (hack for oprofile) */ int avail_to_resrv_perfctr_nmi_bit(unsigned int counter) { BUG_ON(counter > NMI_MAX_COUNTER_BITS); return (!test_bit(counter, &__get_cpu_var(perfctr_nmi_owner))); } /* checks the an msr for availability */ int avail_to_resrv_perfctr_nmi(unsigned int msr) { unsigned int counter; counter = nmi_perfctr_msr_to_bit(msr); BUG_ON(counter > NMI_MAX_COUNTER_BITS); return (!test_bit(counter, &__get_cpu_var(perfctr_nmi_owner))); } int reserve_perfctr_nmi(unsigned int msr) { unsigned int counter; counter = nmi_perfctr_msr_to_bit(msr); BUG_ON(counter > NMI_MAX_COUNTER_BITS); if (!test_and_set_bit(counter, &__get_cpu_var(perfctr_nmi_owner))) return 1; return 0; } void release_perfctr_nmi(unsigned int msr) { unsigned int counter; counter = nmi_perfctr_msr_to_bit(msr); BUG_ON(counter > NMI_MAX_COUNTER_BITS); clear_bit(counter, &__get_cpu_var(perfctr_nmi_owner)); } int reserve_evntsel_nmi(unsigned int msr) { unsigned int counter; counter = nmi_evntsel_msr_to_bit(msr); BUG_ON(counter > NMI_MAX_COUNTER_BITS); if (!test_and_set_bit(counter, &__get_cpu_var(evntsel_nmi_owner))) return 1; return 0; } void release_evntsel_nmi(unsigned int msr) { unsigned int counter; counter = nmi_evntsel_msr_to_bit(msr); BUG_ON(counter > NMI_MAX_COUNTER_BITS); clear_bit(counter, &__get_cpu_var(evntsel_nmi_owner)); } static __cpuinit inline int nmi_known_cpu(void) { switch (boot_cpu_data.x86_vendor) { case X86_VENDOR_AMD: return boot_cpu_data.x86 == 15; case X86_VENDOR_INTEL: if (cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON)) return 1; else return (boot_cpu_data.x86 == 15); } return 0; } /* Run after command line and cpu_init init, but before all other checks */ void nmi_watchdog_default(void) { if (nmi_watchdog != NMI_DEFAULT) return; if (nmi_known_cpu()) nmi_watchdog = NMI_LOCAL_APIC; else nmi_watchdog = NMI_IO_APIC; } 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 static unsigned int adjust_for_32bit_ctr(unsigned int hz) { unsigned int retval = hz; /* * On Intel CPUs with ARCH_PERFMON only 32 bits in the counter * are writable, with higher bits sign extending from bit 31. * So, we can only program the counter with 31 bit values and * 32nd bit should be 1, for 33.. to be 1. * Find the appropriate nmi_hz */ if ((((u64)cpu_khz * 1000) / retval) > 0x7fffffffULL) { retval = ((u64)cpu_khz * 1000) / 0x7fffffffUL + 1; } return retval; } int __init check_nmi_watchdog (void) { int *counts; int cpu; if ((nmi_watchdog == NMI_NONE) || (nmi_watchdog == NMI_DEFAULT)) 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((10*1000)/nmi_hz); // wait 10 ticks for_each_online_cpu(cpu) { if (!per_cpu(nmi_watchdog_ctlblk, cpu).enabled) 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(nmi_watchdog_ctlblk, cpu).enabled = 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) { struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk); nmi_hz = 1; if (wd->perfctr_msr == MSR_ARCH_PERFMON_PERFCTR0) nmi_hz = adjust_for_32bit_ctr(nmi_hz); } 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 disable_lapic_nmi_watchdog(void) { BUG_ON(nmi_watchdog != NMI_LOCAL_APIC); if (atomic_read(&nmi_active) <= 0) return; on_each_cpu(stop_apic_nmi_watchdog, NULL, 0, 1); BUG_ON(atomic_read(&nmi_active) != 0); } static void enable_lapic_nmi_watchdog(void) { BUG_ON(nmi_watchdog != NMI_LOCAL_APIC); /* are we already enabled */ if (atomic_read(&nmi_active) != 0) return; /* are we lapic aware */ if (nmi_known_cpu() <= 0) return; on_each_cpu(setup_apic_nmi_watchdog, NULL, 0, 1); touch_nmi_watchdog(); } void disable_timer_nmi_watchdog(void) { BUG_ON(nmi_watchdog != NMI_IO_APIC); if (atomic_read(&nmi_active) <= 0) return; disable_irq(0); on_each_cpu(stop_apic_nmi_watchdog, NULL, 0, 1); BUG_ON(atomic_read(&nmi_active) != 0); } void enable_timer_nmi_watchdog(void) { BUG_ON(nmi_watchdog != NMI_IO_APIC); if (atomic_read(&nmi_active) == 0) { touch_nmi_watchdog(); on_each_cpu(setup_apic_nmi_watchdog, NULL, 0, 1); enable_irq(0); } } 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 */ /* * Activate the NMI watchdog via the local APIC. * Original code written by Keith Owens. */ /* Note that these events don't tick when the CPU idles. This means the frequency varies with CPU load. */ #define K7_EVNTSEL_ENABLE (1 << 22) #define K7_EVNTSEL_INT (1 << 20) #define K7_EVNTSEL_OS (1 << 17) #define K7_EVNTSEL_USR (1 << 16) #define K7_EVENT_CYCLES_PROCESSOR_IS_RUNNING 0x76 #define K7_NMI_EVENT K7_EVENT_CYCLES_PROCESSOR_IS_RUNNING static int setup_k7_watchdog(void) { unsigned int perfctr_msr, evntsel_msr; unsigned int evntsel; struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk); perfctr_msr = MSR_K7_PERFCTR0; evntsel_msr = MSR_K7_EVNTSEL0; if (!reserve_perfctr_nmi(perfctr_msr)) goto fail; if (!reserve_evntsel_nmi(evntsel_msr)) goto fail1; /* Simulator may not support it */ if (checking_wrmsrl(evntsel_msr, 0UL)) goto fail2; wrmsrl(perfctr_msr, 0UL); evntsel = K7_EVNTSEL_INT | K7_EVNTSEL_OS | K7_EVNTSEL_USR | K7_NMI_EVENT; /* setup the timer */ wrmsr(evntsel_msr, evntsel, 0); wrmsrl(perfctr_msr, -((u64)cpu_khz * 1000 / nmi_hz)); apic_write(APIC_LVTPC, APIC_DM_NMI); evntsel |= K7_EVNTSEL_ENABLE; wrmsr(evntsel_msr, evntsel, 0); wd->perfctr_msr = perfctr_msr; wd->evntsel_msr = evntsel_msr; wd->cccr_msr = 0; //unused wd->check_bit = 1ULL<<63; return 1; fail2: release_evntsel_nmi(evntsel_msr); fail1: release_perfctr_nmi(perfctr_msr); fail: return 0; } static void stop_k7_watchdog(void) { struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk); wrmsr(wd->evntsel_msr, 0, 0); release_evntsel_nmi(wd->evntsel_msr); release_perfctr_nmi(wd->perfctr_msr); } /* Note that these events don't tick when the CPU idles. This means the frequency varies with CPU load. */ #define MSR_P4_MISC_ENABLE_PERF_AVAIL (1<<7) #define P4_ESCR_EVENT_SELECT(N) ((N)<<25) #define P4_ESCR_OS (1<<3) #define P4_ESCR_USR (1<<2) #define P4_CCCR_OVF_PMI0 (1<<26) #define P4_CCCR_OVF_PMI1 (1<<27) #define P4_CCCR_THRESHOLD(N) ((N)<<20) #define P4_CCCR_COMPLEMENT (1<<19) #define P4_CCCR_COMPARE (1<<18) #define P4_CCCR_REQUIRED (3<<16) #define P4_CCCR_ESCR_SELECT(N) ((N)<<13) #define P4_CCCR_ENABLE (1<<12) #define P4_CCCR_OVF (1<<31) /* Set up IQ_COUNTER0 to behave like a clock, by having IQ_CCCR0 filter CRU_ESCR0 (with any non-null event selector) through a complemented max threshold. [IA32-Vol3, Section 14.9.9] */ static int setup_p4_watchdog(void) { unsigned int perfctr_msr, evntsel_msr, cccr_msr; unsigned int evntsel, cccr_val; unsigned int misc_enable, dummy; unsigned int ht_num; struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk); rdmsr(MSR_IA32_MISC_ENABLE, misc_enable, dummy); if (!(misc_enable & MSR_P4_MISC_ENABLE_PERF_AVAIL)) return 0; #ifdef CONFIG_SMP /* detect which hyperthread we are on */ if (smp_num_siblings == 2) { unsigned int ebx, apicid; ebx = cpuid_ebx(1); apicid = (ebx >> 24) & 0xff; ht_num = apicid & 1; } else #endif ht_num = 0; /* performance counters are shared resources * assign each hyperthread its own set * (re-use the ESCR0 register, seems safe * and keeps the cccr_val the same) */ if (!ht_num) { /* logical cpu 0 */ perfctr_msr = MSR_P4_IQ_PERFCTR0; evntsel_msr = MSR_P4_CRU_ESCR0; cccr_msr = MSR_P4_IQ_CCCR0; cccr_val = P4_CCCR_OVF_PMI0 | P4_CCCR_ESCR_SELECT(4); } else { /* logical cpu 1 */ perfctr_msr = MSR_P4_IQ_PERFCTR1; evntsel_msr = MSR_P4_CRU_ESCR0; cccr_msr = MSR_P4_IQ_CCCR1; cccr_val = P4_CCCR_OVF_PMI1 | P4_CCCR_ESCR_SELECT(4); } if (!reserve_perfctr_nmi(perfctr_msr)) goto fail; if (!reserve_evntsel_nmi(evntsel_msr)) goto fail1; evntsel = P4_ESCR_EVENT_SELECT(0x3F) | P4_ESCR_OS | P4_ESCR_USR; cccr_val |= P4_CCCR_THRESHOLD(15) | P4_CCCR_COMPLEMENT | P4_CCCR_COMPARE | P4_CCCR_REQUIRED; wrmsr(evntsel_msr, evntsel, 0); wrmsr(cccr_msr, cccr_val, 0); wrmsrl(perfctr_msr, -((u64)cpu_khz * 1000 / nmi_hz)); apic_write(APIC_LVTPC, APIC_DM_NMI); cccr_val |= P4_CCCR_ENABLE; wrmsr(cccr_msr, cccr_val, 0); wd->perfctr_msr = perfctr_msr; wd->evntsel_msr = evntsel_msr; wd->cccr_msr = cccr_msr; wd->check_bit = 1ULL<<39; return 1; fail1: release_perfctr_nmi(perfctr_msr); fail: return 0; } static void stop_p4_watchdog(void) { struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk); wrmsr(wd->cccr_msr, 0, 0); wrmsr(wd->evntsel_msr, 0, 0); release_evntsel_nmi(wd->evntsel_msr); release_perfctr_nmi(wd->perfctr_msr); } #define ARCH_PERFMON_NMI_EVENT_SEL ARCH_PERFMON_UNHALTED_CORE_CYCLES_SEL #define ARCH_PERFMON_NMI_EVENT_UMASK ARCH_PERFMON_UNHALTED_CORE_CYCLES_UMASK static int setup_intel_arch_watchdog(void) { unsigned int ebx; union cpuid10_eax eax; unsigned int unused; unsigned int perfctr_msr, evntsel_msr; unsigned int evntsel; struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk); /* * Check whether the Architectural PerfMon supports * Unhalted Core Cycles Event or not. * NOTE: Corresponding bit = 0 in ebx indicates event present. */ cpuid(10, &(eax.full), &ebx, &unused, &unused); if ((eax.split.mask_length < (ARCH_PERFMON_UNHALTED_CORE_CYCLES_INDEX+1)) || (ebx & ARCH_PERFMON_UNHALTED_CORE_CYCLES_PRESENT)) goto fail; perfctr_msr = MSR_ARCH_PERFMON_PERFCTR0; evntsel_msr = MSR_ARCH_PERFMON_EVENTSEL0; if (!reserve_perfctr_nmi(perfctr_msr)) goto fail; if (!reserve_evntsel_nmi(evntsel_msr)) goto fail1; wrmsrl(perfctr_msr, 0UL); evntsel = ARCH_PERFMON_EVENTSEL_INT | ARCH_PERFMON_EVENTSEL_OS | ARCH_PERFMON_EVENTSEL_USR | ARCH_PERFMON_NMI_EVENT_SEL | ARCH_PERFMON_NMI_EVENT_UMASK; /* setup the timer */ wrmsr(evntsel_msr, evntsel, 0); nmi_hz = adjust_for_32bit_ctr(nmi_hz); wrmsr(perfctr_msr, (u32)(-((u64)cpu_khz * 1000 / nmi_hz)), 0); apic_write(APIC_LVTPC, APIC_DM_NMI); evntsel |= ARCH_PERFMON_EVENTSEL0_ENABLE; wrmsr(evntsel_msr, evntsel, 0); wd->perfctr_msr = perfctr_msr; wd->evntsel_msr = evntsel_msr; wd->cccr_msr = 0; //unused wd->check_bit = 1ULL << (eax.split.bit_width - 1); return 1; fail1: release_perfctr_nmi(perfctr_msr); fail: return 0; } static void stop_intel_arch_watchdog(void) { unsigned int ebx; union cpuid10_eax eax; unsigned int unused; struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk); /* * Check whether the Architectural PerfMon supports * Unhalted Core Cycles Event or not. * NOTE: Corresponding bit = 0 in ebx indicates event present. */ cpuid(10, &(eax.full), &ebx, &unused, &unused); if ((eax.split.mask_length < (ARCH_PERFMON_UNHALTED_CORE_CYCLES_INDEX+1)) || (ebx & ARCH_PERFMON_UNHALTED_CORE_CYCLES_PRESENT)) return; wrmsr(wd->evntsel_msr, 0, 0); release_evntsel_nmi(wd->evntsel_msr); release_perfctr_nmi(wd->perfctr_msr); } void setup_apic_nmi_watchdog(void *unused) { struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk); /* only support LOCAL and IO APICs for now */ if ((nmi_watchdog != NMI_LOCAL_APIC) && (nmi_watchdog != NMI_IO_APIC)) return; if (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; if (nmi_watchdog == NMI_LOCAL_APIC) { switch (boot_cpu_data.x86_vendor) { case X86_VENDOR_AMD: if (strstr(boot_cpu_data.x86_model_id, "Screwdriver")) return; if (!setup_k7_watchdog()) return; break; case X86_VENDOR_INTEL: if (cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON)) { if (!setup_intel_arch_watchdog()) return; break; } if (!setup_p4_watchdog()) return; break; default: return; } } wd->enabled = 1; atomic_inc(&nmi_active); } void stop_apic_nmi_watchdog(void *unused) { struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk); /* only support LOCAL and IO APICs for now */ if ((nmi_watchdog != NMI_LOCAL_APIC) && (nmi_watchdog != NMI_IO_APIC)) return; if (wd->enabled == 0) return; if (nmi_watchdog == NMI_LOCAL_APIC) { switch (boot_cpu_data.x86_vendor) { case X86_VENDOR_AMD: if (strstr(boot_cpu_data.x86_model_id, "Screwdriver")) return; stop_k7_watchdog(); break; case X86_VENDOR_INTEL: if (cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON)) { stop_intel_arch_watchdog(); break; } stop_p4_watchdog(); break; default: return; } } 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) 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(); struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk); u64 dummy; 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 (wd->enabled) { if (nmi_watchdog == NMI_LOCAL_APIC) { rdmsrl(wd->perfctr_msr, dummy); if (dummy & wd->check_bit){ /* this wasn't a watchdog timer interrupt */ goto done; } /* only Intel uses the cccr msr */ if (wd->cccr_msr != 0) { /* * P4 quirks: * - An overflown perfctr will assert its interrupt * until the OVF flag in its CCCR is cleared. * - LVTPC is masked on interrupt and must be * unmasked by the LVTPC handler. */ rdmsrl(wd->cccr_msr, dummy); dummy &= ~P4_CCCR_OVF; wrmsrl(wd->cccr_msr, dummy); apic_write(APIC_LVTPC, APIC_DM_NMI); /* start the cycle over again */ wrmsrl(wd->perfctr_msr, -((u64)cpu_khz * 1000 / nmi_hz)); } else if (wd->perfctr_msr == MSR_ARCH_PERFMON_PERFCTR0) { /* * ArchPerfom/Core Duo needs to re-unmask * the apic vector */ apic_write(APIC_LVTPC, APIC_DM_NMI); /* ARCH_PERFMON has 32 bit counter writes */ wrmsr(wd->perfctr_msr, (u32)(-((u64)cpu_khz * 1000 / nmi_hz)), 0); } else { /* start the cycle over again */ wrmsrl(wd->perfctr_msr, -((u64)cpu_khz * 1000 / nmi_hz)); } rc = 1; } else if (nmi_watchdog == 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; } else printk(KERN_WARNING "Unknown enabled NMI hardware?!\n"); } done: return rc; } asmlinkage __kprobes void do_nmi(struct pt_regs * regs, long error_code) { nmi_enter(); add_pda(__nmi_count,1); 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; } #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) { 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(avail_to_resrv_perfctr_nmi); EXPORT_SYMBOL(avail_to_resrv_perfctr_nmi_bit); EXPORT_SYMBOL(reserve_perfctr_nmi); EXPORT_SYMBOL(release_perfctr_nmi); EXPORT_SYMBOL(reserve_evntsel_nmi); EXPORT_SYMBOL(release_evntsel_nmi); EXPORT_SYMBOL(disable_timer_nmi_watchdog); EXPORT_SYMBOL(enable_timer_nmi_watchdog); EXPORT_SYMBOL(touch_nmi_watchdog);