diff options
Diffstat (limited to 'kernel/arch/sparc/kernel/nmi.c')
-rw-r--r-- | kernel/arch/sparc/kernel/nmi.c | 272 |
1 files changed, 272 insertions, 0 deletions
diff --git a/kernel/arch/sparc/kernel/nmi.c b/kernel/arch/sparc/kernel/nmi.c new file mode 100644 index 000000000..a9973bb4a --- /dev/null +++ b/kernel/arch/sparc/kernel/nmi.c @@ -0,0 +1,272 @@ +/* Pseudo NMI support on sparc64 systems. + * + * Copyright (C) 2009 David S. Miller <davem@davemloft.net> + * + * The NMI watchdog support and infrastructure is based almost + * entirely upon the x86 NMI support code. + */ +#include <linux/kernel.h> +#include <linux/param.h> +#include <linux/init.h> +#include <linux/percpu.h> +#include <linux/nmi.h> +#include <linux/export.h> +#include <linux/kprobes.h> +#include <linux/kernel_stat.h> +#include <linux/reboot.h> +#include <linux/slab.h> +#include <linux/kdebug.h> +#include <linux/delay.h> +#include <linux/smp.h> + +#include <asm/perf_event.h> +#include <asm/ptrace.h> +#include <asm/pcr.h> + +#include "kstack.h" + +/* We don't have a real NMI on sparc64, but we can fake one + * up using profiling counter overflow interrupts and interrupt + * levels. + * + * The profile overflow interrupts at level 15, so we use + * level 14 as our IRQ off level. + */ + +static int panic_on_timeout; + +/* nmi_active: + * >0: the NMI watchdog is active, but can be disabled + * <0: the NMI watchdog has not been set up, and cannot be enabled + * 0: the NMI watchdog is disabled, but can be enabled + */ +atomic_t nmi_active = ATOMIC_INIT(0); /* oprofile uses this */ +EXPORT_SYMBOL(nmi_active); + +static unsigned int nmi_hz = HZ; +static DEFINE_PER_CPU(short, wd_enabled); +static int endflag __initdata; + +static DEFINE_PER_CPU(unsigned int, last_irq_sum); +static DEFINE_PER_CPU(long, alert_counter); +static DEFINE_PER_CPU(int, nmi_touch); + +void touch_nmi_watchdog(void) +{ + if (atomic_read(&nmi_active)) { + int cpu; + + for_each_present_cpu(cpu) { + if (per_cpu(nmi_touch, cpu) != 1) + per_cpu(nmi_touch, cpu) = 1; + } + } + + touch_softlockup_watchdog(); +} +EXPORT_SYMBOL(touch_nmi_watchdog); + +static void die_nmi(const char *str, struct pt_regs *regs, int do_panic) +{ + int this_cpu = smp_processor_id(); + + if (notify_die(DIE_NMIWATCHDOG, str, regs, 0, + pt_regs_trap_type(regs), SIGINT) == NOTIFY_STOP) + return; + + if (do_panic || panic_on_oops) + panic("Watchdog detected hard LOCKUP on cpu %d", this_cpu); + else + WARN(1, "Watchdog detected hard LOCKUP on cpu %d", this_cpu); +} + +notrace __kprobes void perfctr_irq(int irq, struct pt_regs *regs) +{ + unsigned int sum, touched = 0; + void *orig_sp; + + clear_softint(1 << irq); + + local_cpu_data().__nmi_count++; + + nmi_enter(); + + orig_sp = set_hardirq_stack(); + + if (notify_die(DIE_NMI, "nmi", regs, 0, + pt_regs_trap_type(regs), SIGINT) == NOTIFY_STOP) + touched = 1; + else + pcr_ops->write_pcr(0, pcr_ops->pcr_nmi_disable); + + sum = local_cpu_data().irq0_irqs; + if (__this_cpu_read(nmi_touch)) { + __this_cpu_write(nmi_touch, 0); + touched = 1; + } + if (!touched && __this_cpu_read(last_irq_sum) == sum) { + __this_cpu_inc(alert_counter); + if (__this_cpu_read(alert_counter) == 30 * nmi_hz) + die_nmi("BUG: NMI Watchdog detected LOCKUP", + regs, panic_on_timeout); + } else { + __this_cpu_write(last_irq_sum, sum); + __this_cpu_write(alert_counter, 0); + } + if (__this_cpu_read(wd_enabled)) { + pcr_ops->write_pic(0, pcr_ops->nmi_picl_value(nmi_hz)); + pcr_ops->write_pcr(0, pcr_ops->pcr_nmi_enable); + } + + restore_hardirq_stack(orig_sp); + + nmi_exit(); +} + +static inline unsigned int get_nmi_count(int cpu) +{ + return cpu_data(cpu).__nmi_count; +} + +static __init void nmi_cpu_busy(void *data) +{ + while (endflag == 0) + mb(); +} + +static void report_broken_nmi(int cpu, int *prev_nmi_count) +{ + printk(KERN_CONT "\n"); + + printk(KERN_WARNING + "WARNING: CPU#%d: NMI appears to be stuck (%d->%d)!\n", + cpu, prev_nmi_count[cpu], get_nmi_count(cpu)); + + printk(KERN_WARNING + "Please report this to bugzilla.kernel.org,\n"); + printk(KERN_WARNING + "and attach the output of the 'dmesg' command.\n"); + + per_cpu(wd_enabled, cpu) = 0; + atomic_dec(&nmi_active); +} + +void stop_nmi_watchdog(void *unused) +{ + pcr_ops->write_pcr(0, pcr_ops->pcr_nmi_disable); + __this_cpu_write(wd_enabled, 0); + atomic_dec(&nmi_active); +} + +static int __init check_nmi_watchdog(void) +{ + unsigned int *prev_nmi_count; + int cpu, err; + + if (!atomic_read(&nmi_active)) + return 0; + + prev_nmi_count = kmalloc(nr_cpu_ids * sizeof(unsigned int), GFP_KERNEL); + if (!prev_nmi_count) { + err = -ENOMEM; + goto error; + } + + printk(KERN_INFO "Testing NMI watchdog ... "); + + smp_call_function(nmi_cpu_busy, (void *)&endflag, 0); + + 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) + report_broken_nmi(cpu, prev_nmi_count); + } + endflag = 1; + if (!atomic_read(&nmi_active)) { + kfree(prev_nmi_count); + atomic_set(&nmi_active, -1); + err = -ENODEV; + goto error; + } + printk("OK.\n"); + + nmi_hz = 1; + + kfree(prev_nmi_count); + return 0; +error: + on_each_cpu(stop_nmi_watchdog, NULL, 1); + return err; +} + +void start_nmi_watchdog(void *unused) +{ + __this_cpu_write(wd_enabled, 1); + atomic_inc(&nmi_active); + + pcr_ops->write_pcr(0, pcr_ops->pcr_nmi_disable); + pcr_ops->write_pic(0, pcr_ops->nmi_picl_value(nmi_hz)); + + pcr_ops->write_pcr(0, pcr_ops->pcr_nmi_enable); +} + +static void nmi_adjust_hz_one(void *unused) +{ + if (!__this_cpu_read(wd_enabled)) + return; + + pcr_ops->write_pcr(0, pcr_ops->pcr_nmi_disable); + pcr_ops->write_pic(0, pcr_ops->nmi_picl_value(nmi_hz)); + + pcr_ops->write_pcr(0, pcr_ops->pcr_nmi_enable); +} + +void nmi_adjust_hz(unsigned int new_hz) +{ + nmi_hz = new_hz; + on_each_cpu(nmi_adjust_hz_one, NULL, 1); +} +EXPORT_SYMBOL_GPL(nmi_adjust_hz); + +static int nmi_shutdown(struct notifier_block *nb, unsigned long cmd, void *p) +{ + on_each_cpu(stop_nmi_watchdog, NULL, 1); + return 0; +} + +static struct notifier_block nmi_reboot_notifier = { + .notifier_call = nmi_shutdown, +}; + +int __init nmi_init(void) +{ + int err; + + on_each_cpu(start_nmi_watchdog, NULL, 1); + + err = check_nmi_watchdog(); + if (!err) { + err = register_reboot_notifier(&nmi_reboot_notifier); + if (err) { + on_each_cpu(stop_nmi_watchdog, NULL, 1); + atomic_set(&nmi_active, -1); + } + } + + return err; +} + +static int __init setup_nmi_watchdog(char *str) +{ + if (!strncmp(str, "panic", 5)) + panic_on_timeout = 1; + + return 0; +} +__setup("nmi_watchdog=", setup_nmi_watchdog); |