x86: nmi_watchdog - introduce nmi_watchdog_active() helper

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: macro@linux-mips.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index 32acda25e3cb66bcd13a0cd834f0935f9c04fc8e..8dfe9db87a9e678233b7bfc593d2cebba262ca78 100644 (file)
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -119,10 +119,7 @@ int __init check_nmi_watchdog(void)
        unsigned int *prev_nmi_count;
        int cpu;
 
-       if (nmi_watchdog == NMI_NONE)
-               return 0;
-
-       if (!atomic_read(&nmi_active))
+       if (!nmi_watchdog_active() || !atomic_read(&nmi_active))
                return 0;
 
        prev_nmi_count = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
@@ -317,8 +314,7 @@ void setup_apic_nmi_watchdog(void *unused)
 void stop_apic_nmi_watchdog(void *unused)
 {
        /* only support LOCAL and IO APICs for now */
-       if (nmi_watchdog != NMI_LOCAL_APIC &&
-           nmi_watchdog != NMI_IO_APIC)
+       if (!nmi_watchdog_active())
                return;
        if (__get_cpu_var(wd_enabled) == 0)
                return;
@@ -348,8 +344,7 @@ static DEFINE_PER_CPU(int, nmi_touch);
 
 void touch_nmi_watchdog(void)
 {
-       if (nmi_watchdog == NMI_LOCAL_APIC ||
-               nmi_watchdog == NMI_IO_APIC) {
+       if (nmi_watchdog_active()) {
                unsigned cpu;
 
                /*
@@ -474,7 +469,7 @@ int proc_nmi_enabled(struct ctl_table *table, int write, struct file *file,
        if (!!old_state == !!nmi_watchdog_enabled)
                return 0;
 
-       if (atomic_read(&nmi_active) < 0 || nmi_watchdog == NMI_NONE) {
+       if (atomic_read(&nmi_active) < 0 || !nmi_watchdog_active()) {
                printk(KERN_WARNING
                        "NMI watchdog is permanently disabled\n");
                return -EIO;

diff --git a/include/asm-x86/nmi.h b/include/asm-x86/nmi.h
index 1348e542360f54aed60d954cfdcb0d42f91d23b8..21f8d0202a828ee8f6d1bf14b444e2b340f6cb3d 100644 (file)
--- a/include/asm-x86/nmi.h
+++ b/include/asm-x86/nmi.h
@@ -56,6 +56,19 @@ static inline void localise_nmi_watchdog(void)
        if (nmi_watchdog == NMI_IO_APIC)
                nmi_watchdog = NMI_LOCAL_APIC;
 }
+
+/* check if nmi_watchdog is active (ie was specified at boot) */
+static inline int nmi_watchdog_active(void)
+{
+       /*
+        * actually it should be:
+        *      return (nmi_watchdog == NMI_LOCAL_APIC ||
+        *              nmi_watchdog == NMI_IO_APIC)
+        * but since they are power of two we could use a
+        * cheaper way --cvg
+        */
+       return nmi_watchdog & 0x3;
+}
 #endif
 
 void lapic_watchdog_stop(void);