[PATCH] i386/x86_64: ACPI cpu_idle_wait() fix

[deliverable/linux.git] / arch / i386 / kernel / process.c

diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
index dad02a960e03572046c2e9ced98186c64e7ca5a5..dd53c58f64f1bd944dd65190fc5d8f98bf6c8643 100644 (file)
--- a/arch/i386/kernel/process.c
+++ b/arch/i386/kernel/process.c
@@ -205,7 +205,7 @@ void cpu_idle(void)
 void cpu_idle_wait(void)
 {
        unsigned int cpu, this_cpu = get_cpu();
-       cpumask_t map;
+       cpumask_t map, tmp = current->cpus_allowed;
 
        set_cpus_allowed(current, cpumask_of_cpu(this_cpu));
        put_cpu();
@@ -227,6 +227,8 @@ void cpu_idle_wait(void)
                }
                cpus_and(map, map, cpu_online_map);
        } while (!cpus_empty(map));
+
+       set_cpus_allowed(current, tmp);
 }
 EXPORT_SYMBOL_GPL(cpu_idle_wait);
 
@@ -236,20 +238,28 @@ EXPORT_SYMBOL_GPL(cpu_idle_wait);
  * We execute MONITOR against need_resched and enter optimized wait state
  * through MWAIT. Whenever someone changes need_resched, we would be woken
  * up from MWAIT (without an IPI).
+ *
+ * New with Core Duo processors, MWAIT can take some hints based on CPU
+ * capability.
  */
-static void mwait_idle(void)
+void mwait_idle_with_hints(unsigned long eax, unsigned long ecx)
 {
-       local_irq_enable();
-
-       while (!need_resched()) {
+       if (!need_resched()) {
                __monitor((void *)&current_thread_info()->flags, 0, 0);
                smp_mb();
-               if (need_resched())
-                       break;
-               __mwait(0, 0);
+               if (!need_resched())
+                       __mwait(eax, ecx);
        }
 }
 
+/* Default MONITOR/MWAIT with no hints, used for default C1 state */
+static void mwait_idle(void)
+{
+       local_irq_enable();
+       while (!need_resched())
+               mwait_idle_with_hints(0, 0);
+}
+
 void __devinit select_idle_routine(const struct cpuinfo_x86 *c)
 {
        if (cpu_has(c, X86_FEATURE_MWAIT)) {