Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull SMP/hotplug changes from Ingo Molnar:
 "This is a pretty large, multi-arch series unifying and generalizing
  the various disjunct pieces of idle routines that architectures have
  historically copied from each other and have grown in random, wildly
  inconsistent and sometimes buggy directions:

   101 files changed, 455 insertions(+), 1328 deletions(-)

  this went through a number of review and test iterations before it was
  committed, it was tested on various architectures, was exposed to
  linux-next for quite some time - nevertheless it might cause problems
  on architectures that don't read the mailing lists and don't regularly
  test linux-next.

  This cat herding excercise was motivated by the -rt kernel, and was
  brought to you by Thomas "the Whip" Gleixner."

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (40 commits)
  idle: Remove GENERIC_IDLE_LOOP config switch
  um: Use generic idle loop
  ia64: Make sure interrupts enabled when we "safe_halt()"
  sparc: Use generic idle loop
  idle: Remove unused ARCH_HAS_DEFAULT_IDLE
  bfin: Fix typo in arch_cpu_idle()
  xtensa: Use generic idle loop
  x86: Use generic idle loop
  unicore: Use generic idle loop
  tile: Use generic idle loop
  tile: Enter idle with preemption disabled
  sh: Use generic idle loop
  score: Use generic idle loop
  s390: Use generic idle loop
  powerpc: Use generic idle loop
  parisc: Use generic idle loop
  openrisc: Use generic idle loop
  mn10300: Use generic idle loop
  mips: Use generic idle loop
  microblaze: Use generic idle loop
  ...

2 files changed, 27 insertions, 75 deletions

diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 047d3e40e47..c9a5e2ce8aa 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -57,38 +57,6 @@ static const char *isa_modes[] = {
   "ARM" , "Thumb" , "Jazelle", "ThumbEE"
 };
 
-static volatile int hlt_counter;
-
-void disable_hlt(void)
-{
-	hlt_counter++;
-}
-
-EXPORT_SYMBOL(disable_hlt);
-
-void enable_hlt(void)
-{
-	hlt_counter--;
-	BUG_ON(hlt_counter < 0);
-}
-
-EXPORT_SYMBOL(enable_hlt);
-
-static int __init nohlt_setup(char *__unused)
-{
-	hlt_counter = 1;
-	return 1;
-}
-
-static int __init hlt_setup(char *__unused)
-{
-	hlt_counter = 0;
-	return 1;
-}
-
-__setup("nohlt", nohlt_setup);
-__setup("hlt", hlt_setup);
-
 extern void call_with_stack(void (*fn)(void *), void *arg, void *sp);
 typedef void (*phys_reset_t)(unsigned long);
 
@@ -172,54 +140,38 @@ static void default_idle(void)
 	local_irq_enable();
 }
 
-/*
- * The idle thread.
- * We always respect 'hlt_counter' to prevent low power idle.
- */
-void cpu_idle(void)
+void arch_cpu_idle_prepare(void)
 {
 	local_fiq_enable();
+}
 
-	/* endless idle loop with no priority at all */
-	while (1) {
-		tick_nohz_idle_enter();
-		rcu_idle_enter();
-		ledtrig_cpu(CPU_LED_IDLE_START);
-		while (!need_resched()) {
-#ifdef CONFIG_HOTPLUG_CPU
-			if (cpu_is_offline(smp_processor_id()))
-				cpu_die();
+void arch_cpu_idle_enter(void)
+{
+	ledtrig_cpu(CPU_LED_IDLE_START);
+#ifdef CONFIG_PL310_ERRATA_769419
+	wmb();
 #endif
+}
 
-			/*
-			 * We need to disable interrupts here
-			 * to ensure we don't miss a wakeup call.
-			 */
-			local_irq_disable();
-#ifdef CONFIG_PL310_ERRATA_769419
-			wmb();
+void arch_cpu_idle_exit(void)
+{
+	ledtrig_cpu(CPU_LED_IDLE_END);
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+void arch_cpu_idle_dead(void)
+{
+	cpu_die();
+}
 #endif
-			if (hlt_counter) {
-				local_irq_enable();
-				cpu_relax();
-			} else if (!need_resched()) {
-				stop_critical_timings();
-				if (cpuidle_idle_call())
-					default_idle();
-				start_critical_timings();
-				/*
-				 * default_idle functions must always
-				 * return with IRQs enabled.
-				 */
-				WARN_ON(irqs_disabled());
-			} else
-				local_irq_enable();
-		}
-		ledtrig_cpu(CPU_LED_IDLE_END);
-		rcu_idle_exit();
-		tick_nohz_idle_exit();
-		schedule_preempt_disabled();
-	}
+
+/*
+ * Called from the core idle loop.
+ */
+void arch_cpu_idle(void)
+{
+	if (cpuidle_idle_call())
+		default_idle();
 }
 
 static char reboot_mode = 'h';
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 1f2ccccaf00..4619177bcfe 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -336,7 +336,7 @@ asmlinkage void __cpuinit secondary_start_kernel(void)
 	/*
 	 * OK, it's off to the idle thread for us
 	 */
-	cpu_idle();
+	cpu_startup_entry(CPUHP_ONLINE);
 }
 
 void __init smp_cpus_done(unsigned int max_cpus)