diff options
Diffstat (limited to 'arch/sparc/kernel/nmi.c')
| -rw-r--r-- | arch/sparc/kernel/nmi.c | 246 |
1 files changed, 246 insertions, 0 deletions
diff --git a/arch/sparc/kernel/nmi.c b/arch/sparc/kernel/nmi.c new file mode 100644 index 00000000000..2c0cc72d295 --- /dev/null +++ b/arch/sparc/kernel/nmi.c @@ -0,0 +1,246 @@ +/* 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/module.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/ptrace.h> +#include <asm/local.h> +#include <asm/pcr.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 nmi_watchdog_active; +static int panic_on_timeout; + +int nmi_usable; +EXPORT_SYMBOL_GPL(nmi_usable); + +static unsigned int nmi_hz = HZ; + +static DEFINE_PER_CPU(unsigned int, 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_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) +{ + if (notify_die(DIE_NMIWATCHDOG, str, regs, 0, + pt_regs_trap_type(regs), SIGINT) == NOTIFY_STOP) + return; + + console_verbose(); + bust_spinlocks(1); + + printk(KERN_EMERG "%s", str); + printk(" on CPU%d, ip %08lx, registers:\n", + smp_processor_id(), regs->tpc); + show_regs(regs); + dump_stack(); + + bust_spinlocks(0); + + if (do_panic || panic_on_oops) + panic("Non maskable interrupt"); + + local_irq_enable(); + do_exit(SIGBUS); +} + +notrace __kprobes void perfctr_irq(int irq, struct pt_regs *regs) +{ + unsigned int sum, touched = 0; + int cpu = smp_processor_id(); + + clear_softint(1 << irq); + pcr_ops->write(PCR_PIC_PRIV); + + local_cpu_data().__nmi_count++; + + if (notify_die(DIE_NMI, "nmi", regs, 0, + pt_regs_trap_type(regs), SIGINT) == NOTIFY_STOP) + touched = 1; + + sum = kstat_irqs_cpu(0, cpu); + if (__get_cpu_var(nmi_touch)) { + __get_cpu_var(nmi_touch) = 0; + touched = 1; + } + if (!touched && __get_cpu_var(last_irq_sum) == sum) { + local_inc(&__get_cpu_var(alert_counter)); + if (local_read(&__get_cpu_var(alert_counter)) == 5 * nmi_hz) + die_nmi("BUG: NMI Watchdog detected LOCKUP", + regs, panic_on_timeout); + } else { + __get_cpu_var(last_irq_sum) = sum; + local_set(&__get_cpu_var(alert_counter), 0); + } + if (nmi_usable) { + write_pic(picl_value(nmi_hz)); + pcr_ops->write(pcr_enable); + } +} + +static inline unsigned int get_nmi_count(int cpu) +{ + return cpu_data(cpu).__nmi_count; +} + +static int endflag __initdata; + +static __init void nmi_cpu_busy(void *data) +{ + local_irq_enable_in_hardirq(); + 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"); + + nmi_usable = 0; +} + +static void stop_watchdog(void *unused) +{ + pcr_ops->write(PCR_PIC_PRIV); +} + +static int __init check_nmi_watchdog(void) +{ + unsigned int *prev_nmi_count; + int cpu, err; + + 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 (get_nmi_count(cpu) - prev_nmi_count[cpu] <= 5) + report_broken_nmi(cpu, prev_nmi_count); + } + endflag = 1; + if (!nmi_usable) { + kfree(prev_nmi_count); + err = -ENODEV; + goto error; + } + printk("OK.\n"); + + nmi_hz = 1; + + kfree(prev_nmi_count); + return 0; +error: + on_each_cpu(stop_watchdog, NULL, 1); + return err; +} + +static void start_watchdog(void *unused) +{ + pcr_ops->write(PCR_PIC_PRIV); + write_pic(picl_value(nmi_hz)); + + pcr_ops->write(pcr_enable); +} + +void nmi_adjust_hz(unsigned int new_hz) +{ + nmi_hz = new_hz; + on_each_cpu(start_watchdog, 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_watchdog, NULL, 1); + return 0; +} + +static struct notifier_block nmi_reboot_notifier = { + .notifier_call = nmi_shutdown, +}; + +int __init nmi_init(void) +{ + int err; + + nmi_usable = 1; + + on_each_cpu(start_watchdog, NULL, 1); + + err = check_nmi_watchdog(); + if (!err) { + err = register_reboot_notifier(&nmi_reboot_notifier); + if (err) { + nmi_usable = 0; + on_each_cpu(stop_watchdog, NULL, 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); |