1 files changed, 24 insertions, 21 deletions

diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c
index 7451a4c43c16..a418ee4c8c62 100644
--- a/arch/x86_64/kernel/process.c
+++ b/arch/x86_64/kernel/process.c
@@ -108,17 +108,15 @@ void exit_idle(void)
  */
 static void default_idle(void)
 {
-        local_irq_enable();
-
         current_thread_info()->status &= ~TS_POLLING;
         smp_mb__after_clear_bit();
-        while (!need_resched()) {
-                local_irq_disable();
-                if (!need_resched())
-                        safe_halt();
-                else
-                        local_irq_enable();
-        }
+        local_irq_disable();
+        if (!need_resched()) {
+                /* Enables interrupts one instruction before HLT.
+                   x86 special cases this so there is no race. */
+                safe_halt();
+        } else
+                local_irq_enable();
         current_thread_info()->status |= TS_POLLING;
 }
 
@@ -130,15 +128,7 @@ static void default_idle(void)
 static void poll_idle (void)
 {
         local_irq_enable();
-
-        asm volatile(
-                "2:"
-                "testl %0,%1;"
-                "rep; nop;"
-                "je 2b;"
-                : :
-                "i" (_TIF_NEED_RESCHED),
-                "m" (current_thread_info()->flags));
+        cpu_relax();
 }
 
 void cpu_idle_wait(void)
@@ -219,6 +209,12 @@ void cpu_idle (void)
                                 idle = default_idle;
                         if (cpu_is_offline(smp_processor_id()))
                                 play_dead();
+                        /*
+                         * Idle routines should keep interrupts disabled
+                         * from here on, until they go to idle.
+                         * Otherwise, idle callbacks can misfire.
+                         */
+                        local_irq_disable();
                         enter_idle();
                         idle();
                         /* In many cases the interrupt that ended idle
@@ -256,9 +252,16 @@ void mwait_idle_with_hints(unsigned long eax, unsigned long 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);
+        if (!need_resched()) {
+                __monitor((void *)&current_thread_info()->flags, 0, 0);
+                smp_mb();
+                if (!need_resched())
+                        __sti_mwait(0, 0);
+                else
+                        local_irq_enable();
+        } else {
+                local_irq_enable();
+        }
 }
 
 void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)