From a1a04ec3c7c27a682473fd9beb2c996316a64649 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 21 Mar 2013 22:49:34 +0100
Subject: [PATCH] idle: Provide a generic entry point for the idle code

For now this calls cpu_idle(), but in the long run we want to move the
cpu bringup code to the core and therefor we add a state argument.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Link: http://lkml.kernel.org/r/20130321215233.583190032@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 include/linux/cpu.h |  8 ++++++++
 init/main.c         |  2 +-
 kernel/Makefile     |  1 +
 kernel/cpu/Makefile |  1 +
 kernel/cpu/idle.c   | 10 ++++++++++
 5 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 kernel/cpu/Makefile
 create mode 100644 kernel/cpu/idle.c

diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index ce7a074f2519..7419e30c55fb 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -212,4 +212,12 @@ static inline int disable_nonboot_cpus(void) { return 0; }
 static inline void enable_nonboot_cpus(void) {}
 #endif /* !CONFIG_PM_SLEEP_SMP */
 
+enum cpuhp_state {
+	CPUHP_OFFLINE,
+	CPUHP_ONLINE,
+};
+
+void cpu_startup_entry(enum cpuhp_state state);
+void cpu_idle(void);
+
 #endif /* _LINUX_CPU_H_ */
diff --git a/init/main.c b/init/main.c
index 63534a141b4e..adb179d3e0f8 100644
--- a/init/main.c
+++ b/init/main.c
@@ -384,7 +384,7 @@ static noinline void __init_refok rest_init(void)
 	init_idle_bootup_task(current);
 	schedule_preempt_disabled();
 	/* Call into cpu_idle with preempt disabled */
-	cpu_idle();
+	cpu_startup_entry(CPUHP_ONLINE);
 }
 
 /* Check for early params. */
diff --git a/kernel/Makefile b/kernel/Makefile
index bbde5f1a4486..d1574d47cf27 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -24,6 +24,7 @@ endif
 
 obj-y += sched/
 obj-y += power/
+obj-y += cpu/
 
 obj-$(CONFIG_CHECKPOINT_RESTORE) += kcmp.o
 obj-$(CONFIG_FREEZER) += freezer.o
diff --git a/kernel/cpu/Makefile b/kernel/cpu/Makefile
new file mode 100644
index 000000000000..59ab052ef7a0
--- /dev/null
+++ b/kernel/cpu/Makefile
@@ -0,0 +1 @@
+obj-y	= idle.o
diff --git a/kernel/cpu/idle.c b/kernel/cpu/idle.c
new file mode 100644
index 000000000000..1908f00e0e98
--- /dev/null
+++ b/kernel/cpu/idle.c
@@ -0,0 +1,10 @@
+/*
+ * Generic entry point for the idle threads
+ */
+#include <linux/sched.h>
+#include <linux/cpu.h>
+
+void cpu_startup_entry(enum cpuhp_state state)
+{
+	cpu_idle();
+}