[PATCH] cpu hotplug/x86_64: disable interrupt in play_dead

With physical CPU hotplug, the CPU is hot removed and it should not receive
any interrupts.  Disabling interrupt is much safer.  This basically is what we
do in ia64 & x86.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/asm-x86_64/system.h b/include/asm-x86_64/system.h
index 85348e02ad2e..b34cc2ee222b 100644
--- a/include/asm-x86_64/system.h
+++ b/include/asm-x86_64/system.h
@@ -315,6 +315,8 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
 #define local_irq_enable()      __asm__ __volatile__("sti": : :"memory")
 /* used in the idle loop; sti takes one instruction cycle to complete */
 #define safe_halt()             __asm__ __volatile__("sti; hlt": : :"memory")
+/* used when interrupts are already enabled or to shutdown the processor */
+#define halt()                  __asm__ __volatile__("hlt": : :"memory")
 
 #define irqs_disabled()                 \
 ({                                      \