Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 1fa744e6 authored by Shaohua Li's avatar Shaohua Li Committed by Linus Torvalds
Browse files

[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: default avatarShaohua Li <shaohua.li@intel.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 766c3f94

arch/x86_64/kernel/process.c

+3 −2
Original line number Diff line number Diff line
@@ -157,7 +157,7 @@ EXPORT_SYMBOL_GPL(cpu_idle_wait); 
DECLARE_PER_CPU(int, cpu_state);



#include <asm/nmi.h>

/* We don't actually take CPU down, just spin without interrupts. */

/* We halt the CPU with physical CPU hotplug */

static inline void play_dead(void)

{

	idle_task_exit();
@@ -166,8 +166,9 @@ static inline void play_dead(void) 
	/* Ack it */

	__get_cpu_var(cpu_state) = CPU_DEAD;



	local_irq_disable();

	while (1)

		safe_halt();

		halt();

}

#else

static inline void play_dead(void)

include/asm-x86_64/system.h

+2 −0
Original line number Diff line number Diff line
@@ -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()			\

({					\