[PATCH] cpu state clean after hot remove

Clean CPU states in order to reuse smp boot code for CPU hotplug.

Signed-off-by: Li Shaohua<shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/asm-i386/irq.h

@@ -29,9 +29,11 @@ extern void release_vm86_irqs(struct task_struct *);
 
 #ifdef CONFIG_4KSTACKS
   extern void irq_ctx_init(int cpu);
+  extern void irq_ctx_exit(int cpu);
 # define __ARCH_HAS_DO_SOFTIRQ
 #else
 # define irq_ctx_init(cpu) do { } while (0)
+# define irq_ctx_exit(cpu) do { } while (0)
 #endif
 
 #ifdef CONFIG_IRQBALANCE

include/asm-i386/smp.h

@@ -48,6 +48,14 @@ extern void unlock_ipi_call_lock(void);
 #define MAX_APICID 256
 extern u8 x86_cpu_to_apicid[];
 
+#ifdef CONFIG_HOTPLUG_CPU
+extern void cpu_exit_clear(void);
+extern void cpu_uninit(void);
+
+#define __HAVE_ARCH_SMP_PREPARE_CPU
+extern int smp_prepare_cpu(int cpu);
+#endif
+
 /*
  * This function is needed by all SMP systems. It must _always_ be valid
  * from the initial startup. We map APIC_BASE very early in page_setup(),