/* * linux/arch/i386/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. * Mikael Pettersson : Pentium 4 support 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 "mach_traps.h" /* 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 long, perfctr_nmi_owner); static DEFINE_PER_CPU(unsigned long, evntsel_nmi_owner[3]); /* 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 */ 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 void stop_apic_nmi_watchdog(void *unused); static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu); extern void show_registers(struct pt_regs *regs); extern int unknown_nmi_panic; /* 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: switch (boot_cpu_data.x86) { case 6: return (msr - MSR_P6_PERFCTR0); case 15: 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: switch (boot_cpu_data.x86) { case 6: return (msr - MSR_P6_EVNTSEL0); case 15: 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)[0])) 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)[0]); } static __cpuinit inline int nmi_known_cpu(void) { switch (boot_cpu_data.x86_vendor) { case X86_VENDOR_AMD: return ((boot_cpu_data.x86 == 15) || (boot_cpu_data.x86 == 6)); case X86_VENDOR_INTEL: return ((boot_cpu_data.x86 == 15) || (boot_cpu_data.x86 == 6)); } return 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) { volatile int *endflag = 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) barrier(); } #endif static int __init check_nmi_watchdog(void) { volatile int endflag = 0; unsigned int *prev_nmi_count; int cpu; if ((nmi_watchdog == NMI_NONE) || (nmi_watchdog == NMI_DEFAULT)) return 0; if (!atomic_read(&nmi_active)) return 0; prev_nmi_count = kmalloc(NR_CPUS * sizeof(int), GFP_KERNEL); if (!prev_nmi_count) return -1; printk(KERN_INFO "Testing NMI watchdog ... "); if (nmi_watchdog == NMI_LOCAL_APIC) smp_call_function(nmi_cpu_busy, (void *)&endflag, 0, 0); for_each_possible_cpu(cpu) prev_nmi_count[cpu] = per_cpu(irq_stat, cpu).__nmi_count; local_irq_enable(); mdelay((10*1000)/nmi_hz); // wait 10 ticks for_each_possible_cpu(cpu) { #ifdef CONFIG_SMP /* Check cpu_callin_map here because that is set after the timer is started. */ if (!cpu_isset(cpu, cpu_callin_map)) continue; #endif if (!per_cpu(nmi_watchdog_ctlblk, cpu).enabled) continue; if (nmi_count(cpu) - prev_nmi_count[cpu] <= 5) { printk("CPU#%d: NMI appears to be stuck (%d->%d)!\n", cpu, prev_nmi_count[cpu], nmi_count(cpu)); per_cpu(nmi_watchdog_ctlblk, cpu).enabled = 0; atomic_dec(&nmi_active); } } if (!atomic_read(&nmi_active)) { kfree(prev_nmi_count); atomic_set(&nmi_active, -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 = 1; kfree(prev_nmi_count); return 0; } /* This needs to happen later in boot so counters are working */ late_initcall(check_nmi_watchdog); static int __init setup_nmi_watchdog(char *str) { int nmi; get_option(&str, &nmi); if ((nmi >= NMI_INVALID) || (nmi < NMI_NONE)) return 0; /* * If any other x86 CPU has a local APIC, then * please test the NMI stuff there and send me the * missing bits. Right now Intel P6/P4 and AMD K7 only. */ if ((nmi == NMI_LOCAL_APIC) && (nmi_known_cpu() == 0)) return 0; /* no lapic support */ 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); } } #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) { nmi_pm_active = atomic_read(&nmi_active); disable_lapic_nmi_watchdog(); return 0; } static int lapic_nmi_resume(struct sys_device *dev) { if (nmi_pm_active > 0) enable_lapic_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. */ static void write_watchdog_counter(unsigned int perfctr_msr, const char *descr) { u64 count = (u64)cpu_khz * 1000; do_div(count, nmi_hz); if(descr) Dprintk("setting %s to -0x%08Lx\n", descr, count); wrmsrl(perfctr_msr, 0 - count); } /* 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; 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); write_watchdog_counter(perfctr_msr, "K7_PERFCTR0"); 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; 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); } #define P6_EVNTSEL0_ENABLE (1 << 22) #define P6_EVNTSEL_INT (1 << 20) #define P6_EVNTSEL_OS (1 << 17) #define P6_EVNTSEL_USR (1 << 16) #define P6_EVENT_CPU_CLOCKS_NOT_HALTED 0x79 #define P6_NMI_EVENT P6_EVENT_CPU_CLOCKS_NOT_HALTED static int setup_p6_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_P6_PERFCTR0; evntsel_msr = MSR_P6_EVNTSEL0; if (!reserve_perfctr_nmi(perfctr_msr)) goto fail; if (!reserve_evntsel_nmi(evntsel_msr)) goto fail1; wrmsrl(perfctr_msr, 0UL); evntsel = P6_EVNTSEL_INT | P6_EVNTSEL_OS | P6_EVNTSEL_USR | P6_NMI_EVENT; /* setup the timer */ wrmsr(evntsel_msr, evntsel, 0); write_watchdog_counter(perfctr_msr, "P6_PERFCTR0"); apic_write(APIC_LVTPC, APIC_DM_NMI); evntsel |= P6_EVNTSEL0_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<<39; return 1; fail1: release_perfctr_nmi(perfctr_msr); fail: return 0; } static void stop_p6_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); write_watchdog_counter(perfctr_msr, "P4_IQ_COUNTER0"); 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); } void setup_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 (nmi_watchdog == NMI_LOCAL_APIC) { switch (boot_cpu_data.x86_vendor) { case X86_VENDOR_AMD: if (boot_cpu_data.x86 != 6 && boot_cpu_data.x86 != 15) return; if (!setup_k7_watchdog()) return; break; case X86_VENDOR_INTEL: switch (boot_cpu_data.x86) { case 6: if (boot_cpu_data.x86_model > 0xd) return; if (!setup_p6_watchdog()) return; break; case 15: if (boot_cpu_data.x86_model > 0x4) return; if (!setup_p4_watchdog()) return; break; default: return; } break; default: return; } } __get_cpu_var(nmi_watchdog_ctlblk.enabled) = 1; atomic_inc(&nmi_active); } static 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 (nmi_watchdog == NMI_LOCAL_APIC) { switch (boot_cpu_data.x86_vendor) { case X86_VENDOR_AMD: stop_k7_watchdog(); break; case X86_VENDOR_INTEL: switch (boot_cpu_data.x86) { case 6: if (boot_cpu_data.x86_model > 0xd) break; stop_p6_watchdog(); break; case 15: if (boot_cpu_data.x86_model > 0x4) break; stop_p4_watchdog(); break; } break; default: return; } } __get_cpu_var(nmi_watchdog_ctlblk.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 unsigned int last_irq_sums [NR_CPUS], alert_counter [NR_CPUS]; void touch_nmi_watchdog (void) { int i; /* * Just reset the alert counters, (other CPUs might be * spinning on locks we hold): */ for_each_possible_cpu(i) alert_counter[i] = 0; /* * Tickle the softlockup detector too: */ touch_softlockup_watchdog(); } EXPORT_SYMBOL(touch_nmi_watchdog); extern void die_nmi(struct pt_regs *, const char *msg); 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(); 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 = per_cpu(irq_stat, cpu).apic_timer_irqs; /* if the apic timer isn't firing, this cpu isn't doing much */ if (!touched && last_irq_sums[cpu] == sum) { /* * Ayiee, looks like this CPU is stuck ... * wait a few IRQs (5 seconds) before doing the oops ... */ alert_counter[cpu]++; if (alert_counter[cpu] == 5*nmi_hz) /* * die_nmi will return ONLY if NOTIFY_STOP happens.. */ die_nmi(regs, "BUG: NMI Watchdog detected LOCKUP"); } else { last_irq_sums[cpu] = sum; alert_counter[cpu] = 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 P4 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); } else if (wd->perfctr_msr == MSR_P6_PERFCTR0) { /* Only P6 based Pentium M need to re-unmask * the apic vector but it doesn't hurt * other P6 variant */ apic_write(APIC_LVTPC, APIC_DM_NMI); } /* start the cycle over again */ write_watchdog_counter(wd->perfctr_msr, NULL); 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; } 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(regs, buf); 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 == NMI_DEFAULT) { if (nmi_known_cpu() > 0) nmi_watchdog = NMI_LOCAL_APIC; else nmi_watchdog = NMI_IO_APIC; } 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 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);