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, 12 insertions, 91 deletions

diff --git a/arch/sh/kernel/idle.c b/arch/sh/kernel/idle.c
index 3d5a1b387cc0..2ea4483fd722 100644
--- a/arch/sh/kernel/idle.c
+++ b/arch/sh/kernel/idle.c
@@ -24,98 +24,24 @@
 
 static void (*sh_idle)(void);
 
-static int hlt_counter;
-
-static int __init nohlt_setup(char *__unused)
-{
-        hlt_counter = 1;
-        return 1;
-}
-__setup("nohlt", nohlt_setup);
-
-static int __init hlt_setup(char *__unused)
-{
-        hlt_counter = 0;
-        return 1;
-}
-__setup("hlt", hlt_setup);
-
-static inline int hlt_works(void)
-{
-        return !hlt_counter;
-}
-
-/*
- * On SMP it's slightly faster (but much more power-consuming!)
- * to poll the ->work.need_resched flag instead of waiting for the
- * cross-CPU IPI to arrive. Use this option with caution.
- */
-static void poll_idle(void)
+void default_idle(void)
 {
+        set_bl_bit();
         local_irq_enable();
-        while (!need_resched())
-                cpu_relax();
+        /* Isn't this racy ? */
+        cpu_sleep();
+        clear_bl_bit();
 }
 
-void default_idle(void)
+void arch_cpu_idle_dead(void)
 {
-        if (hlt_works()) {
-                clear_thread_flag(TIF_POLLING_NRFLAG);
-                smp_mb__after_clear_bit();
-
-                set_bl_bit();
-                if (!need_resched()) {
-                        local_irq_enable();
-                        cpu_sleep();
-                } else
-                        local_irq_enable();
-
-                set_thread_flag(TIF_POLLING_NRFLAG);
-                clear_bl_bit();
-        } else
-                poll_idle();
+        play_dead();
 }
 
-/*
- * The idle thread. There's no useful work to be done, so just try to conserve
- * power and have a low exit latency (ie sit in a loop waiting for somebody to
- * say that they'd like to reschedule)
- */
-void cpu_idle(void)
+void arch_cpu_idle(void)
 {
-        unsigned int cpu = smp_processor_id();
-
-        set_thread_flag(TIF_POLLING_NRFLAG);
-
-        /* endless idle loop with no priority at all */
-        while (1) {
-                tick_nohz_idle_enter();
-                rcu_idle_enter();
-
-                while (!need_resched()) {
-                        check_pgt_cache();
-                        rmb();
-
-                        if (cpu_is_offline(cpu))
-                                play_dead();
-
-                        local_irq_disable();
-                        /* Don't trace irqs off for idle */
-                        stop_critical_timings();
-                        if (cpuidle_idle_call())
-                                sh_idle();
-                        /*
-                         * Sanity check to ensure that sh_idle() returns
-                         * with IRQs enabled
-                         */
-                        WARN_ON(irqs_disabled());
-                        start_critical_timings();
-                }
-
-                rcu_idle_exit();
-                tick_nohz_idle_exit();
-                schedule_preempt_disabled();
-        }
+        if (cpuidle_idle_call())
+                sh_idle();
 }
 
 void __init select_idle_routine(void)
@@ -123,13 +49,8 @@ void __init select_idle_routine(void)
         /*
          * If a platform has set its own idle routine, leave it alone.
          */
-        if (sh_idle)
-                return;
-
-        if (hlt_works())
+        if (!sh_idle)
                 sh_idle = default_idle;
-        else
-                sh_idle = poll_idle;
 }
 
 void stop_this_cpu(void *unused)
diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c
index 2062aa88af41..45696451f0ea 100644
--- a/arch/sh/kernel/smp.c
+++ b/arch/sh/kernel/smp.c
@@ -203,7 +203,7 @@ asmlinkage void __cpuinit start_secondary(void)
         set_cpu_online(cpu, true);
         per_cpu(cpu_state, cpu) = CPU_ONLINE;
 
-        cpu_idle();
+        cpu_startup_entry(CPUHP_ONLINE);
 }
 
 extern struct {