[patch 1/2] x86: Add pm_play_dead funcptr to power-efficiently offline CPUs

[venkatesh.pallipadi@intel.com]

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Add a funcptr pm_play_dead (similar to pm_idle) that can take
the offline CPUs to the most power efficient idle state.

This patch just adds the func pointer. The pointer will get initialized
by patch that follows.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
---
 arch/x86/include/asm/smp.h |    2 ++
 arch/x86/kernel/smpboot.c  |    7 ++++++-
 2 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index 19e0d88..0388b81 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -148,6 +148,8 @@ static inline int num_booting_cpus(void)
 {
 	return cpumask_weight(cpu_callout_mask);
 }
+
+extern void (*pm_play_dead)(void);
 #endif /* CONFIG_SMP */
 
 extern unsigned disabled_cpus __cpuinitdata;
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 58d24ef..4f8af6a 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1195,6 +1195,8 @@ __init void prefill_possible_map(void)
 	nr_cpu_ids = possible;
 }
 
+void (*pm_play_dead)(void) = NULL;
+
 #ifdef CONFIG_HOTPLUG_CPU
 
 static void remove_siblinginfo(int cpu)
@@ -1313,7 +1315,10 @@ void play_dead_common(void)
 void native_play_dead(void)
 {
 	play_dead_common();
-	wbinvd_halt();
+	if (pm_play_dead)
+		pm_play_dead();
+	else
+		wbinvd_halt();
 }
 
 #else /* ... !CONFIG_HOTPLUG_CPU */
-- 
1.6.0.6

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