From: Shaohua Li Date: Fri, 6 Jan 2006 08:12:20 +0000 (-0800) Subject: [PATCH] cpu hotplug/x86_64: disable interrupt in play_dead X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=1fa744e6e91a895750b9980d13fcfc5791a0cd91;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git [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 Cc: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c index 7519fc520eb3..3060ed97b755 100644 --- a/arch/x86_64/kernel/process.c +++ b/arch/x86_64/kernel/process.c @@ -157,7 +157,7 @@ EXPORT_SYMBOL_GPL(cpu_idle_wait); DECLARE_PER_CPU(int, cpu_state); #include -/* 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) 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() \ ({ \