/*
* proc handler for /proc/sys/kernel/nmi
*/
int proc_nmi_enabled(struct ctl_table *table, int write,
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, buffer, length, ppos);
if (!!old_state == !!nmi_watchdog_enabled)
return 0;
if (atomic_read(&nmi_active) < 0 || !nmi_watchdog_active()) {
printk(KERN_WARNING
"NMI watchdog is permanently disabled\n");
return -EIO;
}
if (nmi_watchdog == NMI_LOCAL_APIC) {
if (nmi_watchdog_enabled)
enable_lapic_nmi_watchdog();
else
disable_lapic_nmi_watchdog();
} else if (nmi_watchdog == NMI_IO_APIC) {
if (nmi_watchdog_enabled)
enable_ioapic_nmi_watchdog();
else
disable_ioapic_nmi_watchdog();
} else {
printk(KERN_WARNING
"NMI watchdog doesn't know what hardware to touch\n");
return -EIO;
}
return 0;
}
int __init check_nmi_watchdog(void)
{
unsigned int *prev_nmi_count;
int cpu;
if (!nmi_watchdog_active() || !atomic_read(&nmi_active))
return 0;
prev_nmi_count = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
if (!prev_nmi_count)
goto error;
printk(KERN_INFO "Testing NMI watchdog ... ");
#ifdef CONFIG_SMP
if (nmi_watchdog == NMI_LOCAL_APIC)
smp_call_function(nmi_cpu_busy, (void *)&endflag, 0);
#endif
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);
goto error;
}
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 = lapic_adjust_nmi_hz(1);
kfree(prev_nmi_count);
return 0;
error:
if (nmi_watchdog == NMI_IO_APIC) {
if (!timer_through_8259)
legacy_pic->chip->mask(0);
on_each_cpu(__acpi_nmi_disable, NULL, 1);
}
#ifdef CONFIG_X86_32
timer_ack = 0;
#endif
return -1;
}
void stop_apic_nmi_watchdog(void *unused)
{
/* only support LOCAL and IO APICs for now */
if (!nmi_watchdog_active())
return;
if (__get_cpu_var(wd_enabled) == 0)
return;
if (nmi_watchdog == NMI_LOCAL_APIC)
lapic_watchdog_stop();
else
__acpi_nmi_disable(NULL);
__get_cpu_var(wd_enabled) = 0;
atomic_dec(&nmi_active);
}
void stop_apic_nmi_watchdog(void *unused)
{
struct hrtimer *hrtimer = &__get_cpu_var(nmi_watchdog_hrtimer);
/* only support LOCAL and IO APICs for now */
if (!nmi_watchdog_active())
return;
if (__get_cpu_var(wd_enabled) == 0)
return;
/* disable the hrtimer */
hrtimer_cancel(hrtimer);
if (nmi_watchdog == NMI_LOCAL_APIC)
lapic_watchdog_stop();
else
__acpi_nmi_disable(NULL);
__get_cpu_var(wd_enabled) = 0;
atomic_dec(&nmi_active);
}