[tip:smp/hotplug] mn10300: Use generic idle loop

[tip-bot for Thomas Gleixner]

Commit-ID:  af695cd931edab7f202fb616d69d4b746c5d6912
Gitweb:     http://git.kernel.org/tip/af695cd931edab7f202fb616d69d4b746c5d6912
Author:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Thu, 21 Mar 2013 22:49:53 +0100
Committer:  Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Mon, 8 Apr 2013 17:39:27 +0200

mn10300: Use generic idle loop

default_idle() boils down to safe_halt() and the other option is idle
polling. Use the core functionality.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Paul McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Reviewed-by: Cc: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
Cc: Magnus Damm <magnus.damm@xxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/20130321215234.822656036@xxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
 arch/mn10300/Kconfig          |  1 +
 arch/mn10300/kernel/process.c | 70 ++++---------------------------------------
 arch/mn10300/kernel/smp.c     |  2 +-
 3 files changed, 8 insertions(+), 65 deletions(-)

diff --git a/arch/mn10300/Kconfig b/arch/mn10300/Kconfig
index 428da17..ae7158b6 100644
--- a/arch/mn10300/Kconfig
+++ b/arch/mn10300/Kconfig
@@ -13,6 +13,7 @@ config MN10300
 	select MODULES_USE_ELF_RELA
 	select OLD_SIGSUSPEND3
 	select OLD_SIGACTION
+	select GENERIC_IDLE_LOOP
 
 config AM33_2
 	def_bool n
diff --git a/arch/mn10300/kernel/process.c b/arch/mn10300/kernel/process.c
index 84f4e97..2da39fb 100644
--- a/arch/mn10300/kernel/process.c
+++ b/arch/mn10300/kernel/process.c
@@ -50,77 +50,19 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
 void (*pm_power_off)(void);
 EXPORT_SYMBOL(pm_power_off);
 
-#if !defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)
-/*
- * we use this if we don't have any better idle routine
- */
-static void default_idle(void)
-{
-	local_irq_disable();
-	if (!need_resched())
-		safe_halt();
-	else
-		local_irq_enable();
-}
-
-#else /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU  */
 /*
  * 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.
+ *
+ * tglx: No idea why this depends on HOTPLUG_CPU !?!
  */
-static inline void poll_idle(void)
-{
-	int oldval;
-
-	local_irq_enable();
-
-	/*
-	 * Deal with another CPU just having chosen a thread to
-	 * run here:
-	 */
-	oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
-
-	if (!oldval) {
-		set_thread_flag(TIF_POLLING_NRFLAG);
-		while (!need_resched())
-			cpu_relax();
-		clear_thread_flag(TIF_POLLING_NRFLAG);
-	} else {
-		set_need_resched();
-	}
-}
-#endif /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU */
-
-/*
- * 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)
+#if !defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)
+void arch_cpu_idle(void)
 {
-	/* endless idle loop with no priority at all */
-	for (;;) {
-		rcu_idle_enter();
-		while (!need_resched()) {
-			void (*idle)(void);
-
-			smp_rmb();
-			if (!idle) {
-#if defined(CONFIG_SMP) && !defined(CONFIG_HOTPLUG_CPU)
-				idle = poll_idle;
-#else  /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */
-				idle = default_idle;
-#endif /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */
-			}
-			idle();
-		}
-		rcu_idle_exit();
-
-		schedule_preempt_disabled();
-	}
+	safe_halt();
 }
+#endif
 
 void release_segments(struct mm_struct *mm)
 {
diff --git a/arch/mn10300/kernel/smp.c b/arch/mn10300/kernel/smp.c
index eaef5ad..a17f9c9 100644
--- a/arch/mn10300/kernel/smp.c
+++ b/arch/mn10300/kernel/smp.c
@@ -675,7 +675,7 @@ int __init start_secondary(void *unused)
 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 	init_clockevents();
 #endif
-	cpu_idle();
+	cpu_startup_entry(CPUHP_ONLINE);
 	return 0;
 }
 
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