[PATCH] x86: Add abilty to enable/disable nmi watchdog with sysctl

[platform/adaptation/renesas_rcar/renesas_kernel.git] / arch / x86_64 / kernel / nmi.c

diff --git a/arch/x86_64/kernel/nmi.c b/arch/x86_64/kernel/nmi.c
index 9d175dc..3a17411 100644 (file)
--- a/arch/x86_64/kernel/nmi.c
+++ b/arch/x86_64/kernel/nmi.c
@@ -750,6 +750,54 @@ static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu)
        return 0;
 }
 
+/*
+ * proc handler for /proc/sys/kernel/nmi
+ */
+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 is not set yet, then set it */
+       nmi_watchdog_default();
+
+       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 -EIO;
+#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);