[PATCH] x86: Add abilty to enable/disable nmi watchdog with sysctl
Adds a new /proc/sys/kernel/nmi call that will enable/disable the nmi
watchdog.
Signed-off-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Andi Kleen <ak@suse.de>
diff --git a/arch/i386/kernel/nmi.c b/arch/i386/kernel/nmi.c
index acd3fde..28065d0 100644
--- a/arch/i386/kernel/nmi.c
+++ b/arch/i386/kernel/nmi.c
@@ -846,6 +846,58 @@
return 0;
}
+/*
+ * proc handler for /proc/sys/kernel/nmi_watchdog
+ */
+int proc_nmi_enabled(struct ctl_table *table, int write, struct file *file,
+ 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, file, buffer, length, ppos);
+ if (!!old_state == !!nmi_watchdog_enabled)
+ return 0;
+
+ if (atomic_read(&nmi_active) < 0) {
+ printk(KERN_WARNING "NMI watchdog is permanently disabled\n");
+ return -EINVAL;
+ }
+
+ if (nmi_watchdog == NMI_DEFAULT) {
+ if (nmi_known_cpu() > 0)
+ nmi_watchdog = NMI_LOCAL_APIC;
+ else
+ nmi_watchdog = NMI_IO_APIC;
+ }
+
+ 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) {
+ /* FIXME
+ * for some reason these functions don't work
+ */
+ printk("Can not enable/disable NMI on IO APIC\n");
+ return -EINVAL;
+#if 0
+ if (nmi_watchdog_enabled)
+ enable_timer_nmi_watchdog();
+ else
+ disable_timer_nmi_watchdog();
+#endif
+ } else {
+ printk( KERN_WARNING
+ "NMI watchdog doesn't know what hardware to touch\n");
+ return -EIO;
+ }
+ return 0;
+}
+
#endif
EXPORT_SYMBOL(nmi_active);