314 lines
7.0 KiB
C
314 lines
7.0 KiB
C
/* Pseudo NMI support on sparc64 systems.
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*
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* Copyright (C) 2009 David S. Miller <davem@davemloft.net>
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*
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* The NMI watchdog support and infrastructure is based almost
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* entirely upon the x86 NMI support code.
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*/
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#include <linux/kernel.h>
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#include <linux/param.h>
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#include <linux/init.h>
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#include <linux/percpu.h>
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#include <linux/nmi.h>
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#include <linux/export.h>
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#include <linux/kprobes.h>
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#include <linux/kernel_stat.h>
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#include <linux/reboot.h>
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#include <linux/slab.h>
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#include <linux/kdebug.h>
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#include <linux/delay.h>
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#include <linux/smp.h>
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#include <asm/perf_event.h>
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#include <asm/ptrace.h>
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#include <asm/pcr.h>
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#include "kstack.h"
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/* We don't have a real NMI on sparc64, but we can fake one
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* up using profiling counter overflow interrupts and interrupt
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* levels.
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*
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* The profile overflow interrupts at level 15, so we use
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* level 14 as our IRQ off level.
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*/
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static int panic_on_timeout;
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/* nmi_active:
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* >0: the NMI watchdog is active, but can be disabled
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* <0: the NMI watchdog has not been set up, and cannot be enabled
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* 0: the NMI watchdog is disabled, but can be enabled
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*/
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atomic_t nmi_active = ATOMIC_INIT(0); /* oprofile uses this */
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EXPORT_SYMBOL(nmi_active);
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static int nmi_init_done;
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static unsigned int nmi_hz = HZ;
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static DEFINE_PER_CPU(short, wd_enabled);
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static int endflag __initdata;
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static DEFINE_PER_CPU(unsigned int, last_irq_sum);
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static DEFINE_PER_CPU(long, alert_counter);
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static DEFINE_PER_CPU(int, nmi_touch);
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void arch_touch_nmi_watchdog(void)
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{
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if (atomic_read(&nmi_active)) {
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int cpu;
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for_each_present_cpu(cpu) {
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if (per_cpu(nmi_touch, cpu) != 1)
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per_cpu(nmi_touch, cpu) = 1;
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}
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}
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}
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EXPORT_SYMBOL(arch_touch_nmi_watchdog);
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static void die_nmi(const char *str, struct pt_regs *regs, int do_panic)
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{
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int this_cpu = smp_processor_id();
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if (notify_die(DIE_NMIWATCHDOG, str, regs, 0,
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pt_regs_trap_type(regs), SIGINT) == NOTIFY_STOP)
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return;
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if (do_panic || panic_on_oops)
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panic("Watchdog detected hard LOCKUP on cpu %d", this_cpu);
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else
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WARN(1, "Watchdog detected hard LOCKUP on cpu %d", this_cpu);
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}
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notrace __kprobes void perfctr_irq(int irq, struct pt_regs *regs)
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{
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unsigned int sum, touched = 0;
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void *orig_sp;
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clear_softint(1 << irq);
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local_cpu_data().__nmi_count++;
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nmi_enter();
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orig_sp = set_hardirq_stack();
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if (notify_die(DIE_NMI, "nmi", regs, 0,
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pt_regs_trap_type(regs), SIGINT) == NOTIFY_STOP)
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touched = 1;
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else
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pcr_ops->write_pcr(0, pcr_ops->pcr_nmi_disable);
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sum = local_cpu_data().irq0_irqs;
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if (__this_cpu_read(nmi_touch)) {
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__this_cpu_write(nmi_touch, 0);
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touched = 1;
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}
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if (!touched && __this_cpu_read(last_irq_sum) == sum) {
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__this_cpu_inc(alert_counter);
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if (__this_cpu_read(alert_counter) == 30 * nmi_hz)
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die_nmi("BUG: NMI Watchdog detected LOCKUP",
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regs, panic_on_timeout);
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} else {
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__this_cpu_write(last_irq_sum, sum);
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__this_cpu_write(alert_counter, 0);
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}
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if (__this_cpu_read(wd_enabled)) {
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pcr_ops->write_pic(0, pcr_ops->nmi_picl_value(nmi_hz));
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pcr_ops->write_pcr(0, pcr_ops->pcr_nmi_enable);
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}
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restore_hardirq_stack(orig_sp);
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nmi_exit();
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}
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static inline unsigned int get_nmi_count(int cpu)
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{
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return cpu_data(cpu).__nmi_count;
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}
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static __init void nmi_cpu_busy(void *data)
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{
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while (endflag == 0)
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mb();
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}
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static void report_broken_nmi(int cpu, int *prev_nmi_count)
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{
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printk(KERN_CONT "\n");
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printk(KERN_WARNING
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"WARNING: CPU#%d: NMI appears to be stuck (%d->%d)!\n",
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cpu, prev_nmi_count[cpu], get_nmi_count(cpu));
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printk(KERN_WARNING
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"Please report this to bugzilla.kernel.org,\n");
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printk(KERN_WARNING
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"and attach the output of the 'dmesg' command.\n");
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per_cpu(wd_enabled, cpu) = 0;
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atomic_dec(&nmi_active);
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}
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void stop_nmi_watchdog(void *unused)
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{
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if (!__this_cpu_read(wd_enabled))
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return;
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pcr_ops->write_pcr(0, pcr_ops->pcr_nmi_disable);
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__this_cpu_write(wd_enabled, 0);
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atomic_dec(&nmi_active);
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}
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static int __init check_nmi_watchdog(void)
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{
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unsigned int *prev_nmi_count;
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int cpu, err;
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if (!atomic_read(&nmi_active))
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return 0;
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prev_nmi_count = kmalloc_array(nr_cpu_ids, sizeof(unsigned int),
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GFP_KERNEL);
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if (!prev_nmi_count) {
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err = -ENOMEM;
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goto error;
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}
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printk(KERN_INFO "Testing NMI watchdog ... ");
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smp_call_function(nmi_cpu_busy, (void *)&endflag, 0);
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for_each_possible_cpu(cpu)
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prev_nmi_count[cpu] = get_nmi_count(cpu);
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local_irq_enable();
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mdelay((20 * 1000) / nmi_hz); /* wait 20 ticks */
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for_each_online_cpu(cpu) {
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if (!per_cpu(wd_enabled, cpu))
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continue;
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if (get_nmi_count(cpu) - prev_nmi_count[cpu] <= 5)
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report_broken_nmi(cpu, prev_nmi_count);
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}
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endflag = 1;
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if (!atomic_read(&nmi_active)) {
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kfree(prev_nmi_count);
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atomic_set(&nmi_active, -1);
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err = -ENODEV;
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goto error;
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}
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printk("OK.\n");
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nmi_hz = 1;
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kfree(prev_nmi_count);
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return 0;
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error:
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on_each_cpu(stop_nmi_watchdog, NULL, 1);
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return err;
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}
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void start_nmi_watchdog(void *unused)
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{
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if (__this_cpu_read(wd_enabled))
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return;
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__this_cpu_write(wd_enabled, 1);
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atomic_inc(&nmi_active);
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pcr_ops->write_pcr(0, pcr_ops->pcr_nmi_disable);
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pcr_ops->write_pic(0, pcr_ops->nmi_picl_value(nmi_hz));
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pcr_ops->write_pcr(0, pcr_ops->pcr_nmi_enable);
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}
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static void nmi_adjust_hz_one(void *unused)
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{
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if (!__this_cpu_read(wd_enabled))
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return;
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pcr_ops->write_pcr(0, pcr_ops->pcr_nmi_disable);
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pcr_ops->write_pic(0, pcr_ops->nmi_picl_value(nmi_hz));
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pcr_ops->write_pcr(0, pcr_ops->pcr_nmi_enable);
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}
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void nmi_adjust_hz(unsigned int new_hz)
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{
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nmi_hz = new_hz;
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on_each_cpu(nmi_adjust_hz_one, NULL, 1);
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}
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EXPORT_SYMBOL_GPL(nmi_adjust_hz);
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static int nmi_shutdown(struct notifier_block *nb, unsigned long cmd, void *p)
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{
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on_each_cpu(stop_nmi_watchdog, NULL, 1);
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return 0;
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}
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static struct notifier_block nmi_reboot_notifier = {
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.notifier_call = nmi_shutdown,
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};
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int __init nmi_init(void)
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{
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int err;
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on_each_cpu(start_nmi_watchdog, NULL, 1);
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err = check_nmi_watchdog();
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if (!err) {
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err = register_reboot_notifier(&nmi_reboot_notifier);
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if (err) {
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on_each_cpu(stop_nmi_watchdog, NULL, 1);
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atomic_set(&nmi_active, -1);
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}
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}
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nmi_init_done = 1;
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return err;
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}
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static int __init setup_nmi_watchdog(char *str)
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{
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if (!strncmp(str, "panic", 5))
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panic_on_timeout = 1;
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return 0;
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}
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__setup("nmi_watchdog=", setup_nmi_watchdog);
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/*
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* sparc specific NMI watchdog enable function.
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* Enables watchdog if it is not enabled already.
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*/
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int watchdog_nmi_enable(unsigned int cpu)
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{
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if (atomic_read(&nmi_active) == -1) {
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pr_warn("NMI watchdog cannot be enabled or disabled\n");
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return -1;
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}
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/*
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* watchdog thread could start even before nmi_init is called.
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* Just Return in that case. Let nmi_init finish the init
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* process first.
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*/
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if (!nmi_init_done)
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return 0;
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smp_call_function_single(cpu, start_nmi_watchdog, NULL, 1);
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return 0;
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}
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/*
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* sparc specific NMI watchdog disable function.
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* Disables watchdog if it is not disabled already.
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*/
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void watchdog_nmi_disable(unsigned int cpu)
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{
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if (atomic_read(&nmi_active) == -1)
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pr_warn_once("NMI watchdog cannot be enabled or disabled\n");
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else
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smp_call_function_single(cpu, stop_nmi_watchdog, NULL, 1);
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}
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