1 files changed, 7 insertions, 34 deletions

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index e2319f39988b..290183e9731a 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -56,15 +56,6 @@ asmlinkage extern void ret_from_fork(void);
 
 unsigned long kernel_thread_flags = CLONE_VM | CLONE_UNTRACED;
 
-unsigned long boot_option_idle_override = 0;
-EXPORT_SYMBOL(boot_option_idle_override);
-
-/*
- * Powermanagement idle function, if any..
- */
-void (*pm_idle)(void);
-EXPORT_SYMBOL(pm_idle);
-
 static ATOMIC_NOTIFIER_HEAD(idle_notifier);
 
 void idle_notifier_register(struct notifier_block *n)
@@ -94,25 +85,6 @@ void exit_idle(void)
         __exit_idle();
 }
 
-/*
- * We use this if we don't have any better
- * idle routine..
- */
-void default_idle(void)
-{
-        current_thread_info()->status &= ~TS_POLLING;
-        /*
-         * TS_POLLING-cleared state must be visible before we
-         * test NEED_RESCHED:
-         */
-        smp_mb();
-        if (!need_resched())
-                safe_halt();    /* enables interrupts racelessly */
-        else
-                local_irq_enable();
-        current_thread_info()->status |= TS_POLLING;
-}
-
 #ifdef CONFIG_HOTPLUG_CPU
 DECLARE_PER_CPU(int, cpu_state);
 
@@ -150,12 +122,9 @@ void cpu_idle(void)
         while (1) {
                 tick_nohz_stop_sched_tick();
                 while (!need_resched()) {
-                        void (*idle)(void);
 
                         rmb();
-                        idle = pm_idle;
-                        if (!idle)
-                                idle = default_idle;
+
                         if (cpu_is_offline(smp_processor_id()))
                                 play_dead();
                         /*
@@ -165,7 +134,7 @@ void cpu_idle(void)
                          */
                         local_irq_disable();
                         enter_idle();
-                        idle();
+                        pm_idle();
                         /* In many cases the interrupt that ended idle
                            has already called exit_idle. But some idle
                            loops can be woken up without interrupt. */
@@ -294,6 +263,7 @@ void flush_thread(void)
         /*
          * Forget coprocessor state..
          */
+        tsk->fpu_counter = 0;
         clear_fpu(tsk);
         clear_used_math();
 }
@@ -658,8 +628,11 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
         /* If the task has used fpu the last 5 timeslices, just do a full
          * restore of the math state immediately to avoid the trap; the
          * chances of needing FPU soon are obviously high now
+         *
+         * tsk_used_math() checks prevent calling math_state_restore(),
+         * which can sleep in the case of !tsk_used_math()
          */
-        if (next_p->fpu_counter>5)
+        if (tsk_used_math(next_p) && next_p->fpu_counter > 5)
                 math_state_restore();
         return prev_p;
 }