1 files changed, 28 insertions, 24 deletions

diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c
index 49f7fac6229e..a418ee4c8c62 100644
--- a/arch/x86_64/kernel/process.c
+++ b/arch/x86_64/kernel/process.c
@@ -88,9 +88,8 @@ void enter_idle(void)
 
 static void __exit_idle(void)
 {
-        if (read_pda(isidle) == 0)
+        if (test_and_clear_bit_pda(0, isidle) == 0)
                 return;
-        write_pda(isidle, 0);
         atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);
 }
 
@@ -109,17 +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;
 }
 
@@ -131,21 +128,13 @@ 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)
 {
         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();
@@ -168,6 +157,8 @@ 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);
 
@@ -218,6 +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
@@ -255,9 +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)