Move x86_64 idle notifiers to generic

Move the x86_64 idle notifiers originally by Andi Kleen and Venkatesh
Pallipadi to generic.

Change-Id: Idf29cda15be151f494ff245933c12462643388d5
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Todd Poynor <toddpoynor@google.com>
diff --git a/arch/x86/include/asm/idle.h b/arch/x86/include/asm/idle.h
index c5d1785..02bab09 100644
--- a/arch/x86/include/asm/idle.h
+++ b/arch/x86/include/asm/idle.h
@@ -1,13 +1,6 @@
 #ifndef _ASM_X86_IDLE_H
 #define _ASM_X86_IDLE_H
 
-#define IDLE_START 1
-#define IDLE_END 2
-
-struct notifier_block;
-void idle_notifier_register(struct notifier_block *n);
-void idle_notifier_unregister(struct notifier_block *n);
-
 #ifdef CONFIG_X86_64
 void enter_idle(void);
 void exit_idle(void);
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 6e338e3..918f468 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -61,19 +61,6 @@
 
 #ifdef CONFIG_X86_64
 static DEFINE_PER_CPU(unsigned char, is_idle);
-static ATOMIC_NOTIFIER_HEAD(idle_notifier);
-
-void idle_notifier_register(struct notifier_block *n)
-{
-	atomic_notifier_chain_register(&idle_notifier, n);
-}
-EXPORT_SYMBOL_GPL(idle_notifier_register);
-
-void idle_notifier_unregister(struct notifier_block *n)
-{
-	atomic_notifier_chain_unregister(&idle_notifier, n);
-}
-EXPORT_SYMBOL_GPL(idle_notifier_unregister);
 #endif
 
 struct kmem_cache *task_xstate_cachep;
@@ -288,14 +275,14 @@
 void enter_idle(void)
 {
 	this_cpu_write(is_idle, 1);
-	atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL);
+	idle_notifier_call_chain(IDLE_START);
 }
 
 static void __exit_idle(void)
 {
 	if (x86_test_and_clear_bit_percpu(0, is_idle) == 0)
 		return;
-	atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);
+	idle_notifier_call_chain(IDLE_END);
 }
 
 /* Called from interrupts to signify idle end */
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index c0fb6b1..42702f2 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -291,4 +291,11 @@
 bool cpu_report_death(void);
 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
 
+#define IDLE_START 1
+#define IDLE_END 2
+
+void idle_notifier_register(struct notifier_block *n);
+void idle_notifier_unregister(struct notifier_block *n);
+void idle_notifier_call_chain(unsigned long val);
+
 #endif /* _LINUX_CPU_H_ */
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 94bbe46..eec9bd0 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -823,3 +823,23 @@
 {
 	cpumask_copy(to_cpumask(cpu_online_bits), src);
 }
+
+static ATOMIC_NOTIFIER_HEAD(idle_notifier);
+
+void idle_notifier_register(struct notifier_block *n)
+{
+	atomic_notifier_chain_register(&idle_notifier, n);
+}
+EXPORT_SYMBOL_GPL(idle_notifier_register);
+
+void idle_notifier_unregister(struct notifier_block *n)
+{
+	atomic_notifier_chain_unregister(&idle_notifier, n);
+}
+EXPORT_SYMBOL_GPL(idle_notifier_unregister);
+
+void idle_notifier_call_chain(unsigned long val)
+{
+	atomic_notifier_call_chain(&idle_notifier, val, NULL);
+}
+EXPORT_SYMBOL_GPL(idle_notifier_call_chain);