diff --git a/arch/arm/include/asm/barrier.h b/arch/arm/include/asm/barrier.h index 69772e742a0a..83ae97c049d9 100644 --- a/arch/arm/include/asm/barrier.h +++ b/arch/arm/include/asm/barrier.h @@ -11,6 +11,8 @@ #define sev() __asm__ __volatile__ ("sev" : : : "memory") #define wfe() __asm__ __volatile__ ("wfe" : : : "memory") #define wfi() __asm__ __volatile__ ("wfi" : : : "memory") +#else +#define wfe() do { } while (0) #endif #if __LINUX_ARM_ARCH__ >= 7 diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h index c3d5fc124a05..768b6fe7640e 100644 --- a/arch/arm/include/asm/processor.h +++ b/arch/arm/include/asm/processor.h @@ -77,7 +77,11 @@ extern void release_thread(struct task_struct *); unsigned long get_wchan(struct task_struct *p); #if __LINUX_ARM_ARCH__ == 6 || defined(CONFIG_ARM_ERRATA_754327) -#define cpu_relax() smp_mb() +#define cpu_relax() \ + do { \ + smp_mb(); \ + __asm__ __volatile__("nop; nop; nop; nop; nop; nop; nop; nop; nop; nop;"); \ + } while (0) #else #define cpu_relax() barrier() #endif diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c index c15318431986..6f77f52baf02 100644 --- a/arch/arm/kernel/machine_kexec.c +++ b/arch/arm/kernel/machine_kexec.c @@ -91,8 +91,11 @@ void machine_crash_nonpanic_core(void *unused) set_cpu_online(smp_processor_id(), false); atomic_dec(&waiting_for_crash_ipi); - while (1) + + while (1) { cpu_relax(); + wfe(); + } } void crash_smp_send_stop(void) diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 65f85737c6a2..844bb2f1ddef 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -602,8 +602,10 @@ static void ipi_cpu_stop(unsigned int cpu) local_fiq_disable(); local_irq_disable(); - while (1) + while (1) { cpu_relax(); + wfe(); + } } static DEFINE_PER_CPU(struct completion *, cpu_completion); diff --git a/arch/arm/mach-omap2/prm_common.c b/arch/arm/mach-omap2/prm_common.c index 09180a59b1c9..2f215facba10 100644 --- a/arch/arm/mach-omap2/prm_common.c +++ b/arch/arm/mach-omap2/prm_common.c @@ -528,8 +528,10 @@ void omap_prm_reset_system(void) prm_ll_data->reset_system(); - while (1) + while (1) { cpu_relax(); + wfe(); + } } /**