diff options
Diffstat (limited to 'arch/x86_64/kernel/nmi.c')
| -rw-r--r-- | arch/x86_64/kernel/nmi.c | 488 |
1 files changed, 488 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/nmi.c b/arch/x86_64/kernel/nmi.c new file mode 100644 index 000000000000..d9867de6a626 --- /dev/null +++ b/arch/x86_64/kernel/nmi.c @@ -0,0 +1,488 @@ +/* + * 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/config.h> +#include <linux/mm.h> +#include <linux/irq.h> +#include <linux/delay.h> +#include <linux/bootmem.h> +#include <linux/smp_lock.h> +#include <linux/interrupt.h> +#include <linux/mc146818rtc.h> +#include <linux/kernel_stat.h> +#include <linux/module.h> +#include <linux/sysdev.h> +#include <linux/nmi.h> +#include <linux/sysctl.h> + +#include <asm/smp.h> +#include <asm/mtrr.h> +#include <asm/mpspec.h> +#include <asm/nmi.h> +#include <asm/msr.h> +#include <asm/proto.h> +#include <asm/kdebug.h> + +/* + * lapic_nmi_owner tracks the ownership of the lapic NMI hardware: + * - it may be reserved by some other driver, or not + * - when not reserved by some other driver, it may be used for + * the NMI watchdog, or not + * + * This is maintained separately from nmi_active because the NMI + * watchdog may also be driven from the I/O APIC timer. + */ +static DEFINE_SPINLOCK(lapic_nmi_owner_lock); +static unsigned int lapic_nmi_owner; +#define LAPIC_NMI_WATCHDOG (1<<0) +#define LAPIC_NMI_RESERVED (1<<1) + +/* nmi_active: + * +1: the lapic NMI watchdog is active, but can be disabled + * 0: the lapic NMI watchdog has not been set up, and cannot + * be enabled + * -1: the lapic NMI watchdog is disabled, but can be enabled + */ +int nmi_active; /* oprofile uses this */ +int panic_on_timeout; + +unsigned int nmi_watchdog = NMI_DEFAULT; +static unsigned int nmi_hz = HZ; +unsigned int nmi_perfctr_msr; /* the MSR to reset in NMI handler */ + +/* 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 + +#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 + +/* Run after command line and cpu_init init, but before all other checks */ +void __init nmi_watchdog_default(void) +{ + if (nmi_watchdog != NMI_DEFAULT) + return; + + /* For some reason the IO APIC watchdog doesn't work on the AMD + 8111 chipset. For now switch to local APIC mode using + perfctr0 there. On Intel CPUs we don't have code to handle + the perfctr and the IO-APIC seems to work, so use that. */ + + if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) { + nmi_watchdog = NMI_LOCAL_APIC; + printk(KERN_INFO + "Using local APIC NMI watchdog using perfctr0\n"); + } else { + printk(KERN_INFO "Using IO APIC NMI watchdog\n"); + nmi_watchdog = NMI_IO_APIC; + } +} + +/* Why is there no CPUID flag for this? */ +static __init int cpu_has_lapic(void) +{ + switch (boot_cpu_data.x86_vendor) { + case X86_VENDOR_INTEL: + case X86_VENDOR_AMD: + return boot_cpu_data.x86 >= 6; + /* .... add more cpus here or find a different way to figure this out. */ + default: + return 0; + } +} + +int __init check_nmi_watchdog (void) +{ + int counts[NR_CPUS]; + int cpu; + + if (nmi_watchdog == NMI_LOCAL_APIC && !cpu_has_lapic()) { + nmi_watchdog = NMI_NONE; + return -1; + } + + printk(KERN_INFO "testing NMI watchdog ... "); + + 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 (cpu = 0; cpu < NR_CPUS; 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 (cpu_pda[cpu].__nmi_count - counts[cpu] <= 5) { + printk("CPU#%d: NMI appears to be stuck (%d)!\n", + cpu, + cpu_pda[cpu].__nmi_count); + nmi_active = 0; + lapic_nmi_owner &= ~LAPIC_NMI_WATCHDOG; + return -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; + + 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) + return 0; + nmi_watchdog = nmi; + return 1; +} + +__setup("nmi_watchdog=", setup_nmi_watchdog); + +static void disable_lapic_nmi_watchdog(void) +{ + if (nmi_active <= 0) + return; + switch (boot_cpu_data.x86_vendor) { + case X86_VENDOR_AMD: + wrmsr(MSR_K7_EVNTSEL0, 0, 0); + break; + case X86_VENDOR_INTEL: + wrmsr(MSR_IA32_EVNTSEL0, 0, 0); + break; + } + nmi_active = -1; + /* tell do_nmi() and others that we're not active any more */ + nmi_watchdog = 0; +} + +static void enable_lapic_nmi_watchdog(void) +{ + if (nmi_active < 0) { + nmi_watchdog = NMI_LOCAL_APIC; + setup_apic_nmi_watchdog(); + } +} + +int reserve_lapic_nmi(void) +{ + unsigned int old_owner; + + spin_lock(&lapic_nmi_owner_lock); + old_owner = lapic_nmi_owner; + lapic_nmi_owner |= LAPIC_NMI_RESERVED; + spin_unlock(&lapic_nmi_owner_lock); + if (old_owner & LAPIC_NMI_RESERVED) + return -EBUSY; + if (old_owner & LAPIC_NMI_WATCHDOG) + disable_lapic_nmi_watchdog(); + return 0; +} + +void release_lapic_nmi(void) +{ + unsigned int new_owner; + + spin_lock(&lapic_nmi_owner_lock); + new_owner = lapic_nmi_owner & ~LAPIC_NMI_RESERVED; + lapic_nmi_owner = new_owner; + spin_unlock(&lapic_nmi_owner_lock); + if (new_owner & LAPIC_NMI_WATCHDOG) + enable_lapic_nmi_watchdog(); +} + +void disable_timer_nmi_watchdog(void) +{ + if ((nmi_watchdog != NMI_IO_APIC) || (nmi_active <= 0)) + return; + + disable_irq(0); + unset_nmi_callback(); + nmi_active = -1; + nmi_watchdog = NMI_NONE; +} + +void enable_timer_nmi_watchdog(void) +{ + if (nmi_active < 0) { + nmi_watchdog = NMI_IO_APIC; + touch_nmi_watchdog(); + nmi_active = 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, u32 state) +{ + nmi_pm_active = 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; + + if (nmi_active == 0 || nmi_watchdog != NMI_LOCAL_APIC) + 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 setup_k7_watchdog(void) +{ + int i; + unsigned int evntsel; + + /* No check, so can start with slow frequency */ + nmi_hz = 1; + + /* XXX should check these in EFER */ + + nmi_perfctr_msr = MSR_K7_PERFCTR0; + + for(i = 0; i < 4; ++i) { + /* Simulator may not support it */ + if (checking_wrmsrl(MSR_K7_EVNTSEL0+i, 0UL)) + return; + wrmsrl(MSR_K7_PERFCTR0+i, 0UL); + } + + evntsel = K7_EVNTSEL_INT + | K7_EVNTSEL_OS + | K7_EVNTSEL_USR + | K7_NMI_EVENT; + + wrmsr(MSR_K7_EVNTSEL0, evntsel, 0); + wrmsrl(MSR_K7_PERFCTR0, -((u64)cpu_khz*1000) / nmi_hz); + apic_write(APIC_LVTPC, APIC_DM_NMI); + evntsel |= K7_EVNTSEL_ENABLE; + wrmsr(MSR_K7_EVNTSEL0, evntsel, 0); +} + +void setup_apic_nmi_watchdog(void) +{ + switch (boot_cpu_data.x86_vendor) { + case X86_VENDOR_AMD: + if (boot_cpu_data.x86 < 6) + return; + if (strstr(boot_cpu_data.x86_model_id, "Screwdriver")) + return; + setup_k7_watchdog(); + break; + default: + return; + } + lapic_nmi_owner = LAPIC_NMI_WATCHDOG; + nmi_active = 1; +} + +/* + * 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 (i = 0; i < NR_CPUS; i++) + alert_counter[i] = 0; +} + +void nmi_watchdog_tick (struct pt_regs * regs, unsigned reason) +{ + int sum, cpu; + + cpu = safe_smp_processor_id(); + sum = read_pda(apic_timer_irqs); + if (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) { + if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) + == NOTIFY_STOP) { + alert_counter[cpu] = 0; + return; + } + die_nmi("NMI Watchdog detected LOCKUP on CPU%d", regs); + } + } else { + last_irq_sums[cpu] = sum; + alert_counter[cpu] = 0; + } + if (nmi_perfctr_msr) + wrmsr(nmi_perfctr_msr, -(cpu_khz/nmi_hz*1000), -1); +} + +static int dummy_nmi_callback(struct pt_regs * regs, int cpu) +{ + return 0; +} + +static nmi_callback_t nmi_callback = dummy_nmi_callback; + +asmlinkage void do_nmi(struct pt_regs * regs, long error_code) +{ + int cpu = safe_smp_processor_id(); + + nmi_enter(); + add_pda(__nmi_count,1); + if (!nmi_callback(regs, cpu)) + default_do_nmi(regs); + nmi_exit(); +} + +void set_nmi_callback(nmi_callback_t callback) +{ + nmi_callback = callback; +} + +void unset_nmi_callback(void) +{ + nmi_callback = dummy_nmi_callback; +} + +#ifdef CONFIG_SYSCTL + +static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu) +{ + unsigned char reason = get_nmi_reason(); + char buf[64]; + + if (!(reason & 0xc0)) { + sprintf(buf, "NMI received for unknown reason %02x\n", reason); + die_nmi(buf,regs); + } + return 0; +} + +/* + * proc handler for /proc/sys/kernel/unknown_nmi_panic + */ +int proc_unknown_nmi_panic(struct ctl_table *table, int write, struct file *file, + void __user *buffer, size_t *length, loff_t *ppos) +{ + int old_state; + + old_state = unknown_nmi_panic; + proc_dointvec(table, write, file, buffer, length, ppos); + if (!!old_state == !!unknown_nmi_panic) + return 0; + + if (unknown_nmi_panic) { + if (reserve_lapic_nmi() < 0) { + unknown_nmi_panic = 0; + return -EBUSY; + } else { + set_nmi_callback(unknown_nmi_panic_callback); + } + } else { + release_lapic_nmi(); + unset_nmi_callback(); + } + return 0; +} + +#endif + +EXPORT_SYMBOL(nmi_active); +EXPORT_SYMBOL(nmi_watchdog); +EXPORT_SYMBOL(reserve_lapic_nmi); +EXPORT_SYMBOL(release_lapic_nmi); +EXPORT_SYMBOL(disable_timer_nmi_watchdog); +EXPORT_SYMBOL(enable_timer_nmi_watchdog); +EXPORT_SYMBOL(touch_nmi_watchdog); |