Merge branch 'linus' into timers/nohz

1 files changed, 43 insertions, 51 deletions

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index c0a5c2a687e..9a10c189792 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(1);
 		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 +134,10 @@ void cpu_idle(void)
 			 */
 			local_irq_disable();
 			enter_idle();
-			idle();
+			/* Don't trace irqs off for idle */
+			stop_critical_timings();
+			pm_idle();
+			start_critical_timings();
 			/* 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 +266,7 @@ void flush_thread(void)
 	/*
 	 * Forget coprocessor state..
 	 */
+	tsk->fpu_counter = 0;
 	clear_fpu(tsk);
 	clear_used_math();
 }
@@ -365,10 +338,10 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
 	p->thread.fs = me->thread.fs;
 	p->thread.gs = me->thread.gs;
 
-	asm("mov %%gs,%0" : "=m" (p->thread.gsindex));
-	asm("mov %%fs,%0" : "=m" (p->thread.fsindex));
-	asm("mov %%es,%0" : "=m" (p->thread.es));
-	asm("mov %%ds,%0" : "=m" (p->thread.ds));
+	savesegment(gs, p->thread.gsindex);
+	savesegment(fs, p->thread.fsindex);
+	savesegment(es, p->thread.es);
+	savesegment(ds, p->thread.ds);
 
 	if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) {
 		p->thread.io_bitmap_ptr = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL);
@@ -407,7 +380,9 @@ out:
 void
 start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
 {
-	asm volatile("movl %0, %%fs; movl %0, %%es; movl %0, %%ds" :: "r"(0));
+	loadsegment(fs, 0);
+	loadsegment(es, 0);
+	loadsegment(ds, 0);
 	load_gs_index(0);
 	regs->ip		= new_ip;
 	regs->sp		= new_sp;
@@ -566,6 +541,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 				 *next = &next_p->thread;
 	int cpu = smp_processor_id();
 	struct tss_struct *tss = &per_cpu(init_tss, cpu);
+	unsigned fsindex, gsindex;
 
 	/* we're going to use this soon, after a few expensive things */
 	if (next_p->fpu_counter>5)
@@ -580,22 +556,38 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 	 * Switch DS and ES.
 	 * This won't pick up thread selector changes, but I guess that is ok.
 	 */
-	asm volatile("mov %%es,%0" : "=m" (prev->es));
+	savesegment(es, prev->es);
 	if (unlikely(next->es | prev->es))
 		loadsegment(es, next->es); 
-	
-	asm volatile ("mov %%ds,%0" : "=m" (prev->ds));
+
+	savesegment(ds, prev->ds);
 	if (unlikely(next->ds | prev->ds))
 		loadsegment(ds, next->ds);
 
+
+	/* We must save %fs and %gs before load_TLS() because
+	 * %fs and %gs may be cleared by load_TLS().
+	 *
+	 * (e.g. xen_load_tls())
+	 */
+	savesegment(fs, fsindex);
+	savesegment(gs, gsindex);
+
 	load_TLS(next, cpu);
 
+	/*
+	 * Leave lazy mode, flushing any hypercalls made here.
+	 * This must be done before restoring TLS segments so
+	 * the GDT and LDT are properly updated, and must be
+	 * done before math_state_restore, so the TS bit is up
+	 * to date.
+	 */
+	arch_leave_lazy_cpu_mode();
+
 	/* 
 	 * Switch FS and GS.
 	 */
 	{ 
-		unsigned fsindex;
-		asm volatile("movl %%fs,%0" : "=r" (fsindex)); 
 		/* segment register != 0 always requires a reload. 
 		   also reload when it has changed. 
 		   when prev process used 64bit base always reload
@@ -613,10 +605,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 		if (next->fs) 
 			wrmsrl(MSR_FS_BASE, next->fs); 
 		prev->fsindex = fsindex;
-	}
-	{ 
-		unsigned gsindex;
-		asm volatile("movl %%gs,%0" : "=r" (gsindex)); 
+
 		if (unlikely(gsindex | next->gsindex | prev->gs)) {
 			load_gs_index(next->gsindex);
 			if (gsindex)
@@ -658,8 +647,11 @@ __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;
 }
@@ -794,7 +786,7 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
 			set_32bit_tls(task, FS_TLS, addr);
 			if (doit) {
 				load_TLS(&task->thread, cpu);
-				asm volatile("movl %0,%%fs" :: "r"(FS_TLS_SEL));
+				loadsegment(fs, FS_TLS_SEL);
 			}
 			task->thread.fsindex = FS_TLS_SEL;
 			task->thread.fs = 0;
@@ -804,7 +796,7 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
 			if (doit) {
 				/* set the selector to 0 to not confuse
 				   __switch_to */
-				asm volatile("movl %0,%%fs" :: "r" (0));
+				loadsegment(fs, 0);
 				ret = checking_wrmsrl(MSR_FS_BASE, addr);
 			}
 		}
@@ -827,7 +819,7 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
 		if (task->thread.gsindex == GS_TLS_SEL)
 			base = read_32bit_tls(task, GS_TLS);
 		else if (doit) {
-			asm("movl %%gs,%0" : "=r" (gsindex));
+			savesegment(gs, gsindex);
 			if (gsindex)
 				rdmsrl(MSR_KERNEL_GS_BASE, base);
 			else