diff --git a/arch/arm/include/asm/barrier.h b/arch/arm/include/asm/barrier.h index 69772e742a0acdc16dbf76f2130a8025af41b6c0..83ae97c049d9bd48b474f0127164c71628bf05c0 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 1bf65b47808a1b99cc574d4340c3a41491fd76a6..cb2a3423b7148cfaa5f0cedc8b8e8611c9e9beb7 100644 --- a/arch/arm/include/asm/processor.h +++ b/arch/arm/include/asm/processor.h @@ -95,7 +95,11 @@ 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 dd2eb5f76b9f0a7d64f50169dd0d04a402b2ae67..76300f3813e89bc48a76d83dc3076d9f7b79ee84 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 1d6f5ea522f49184c53a7d996769104107b4de8e..a3ce7c5365fa8e45c41c068d958caf1f9ccabbda 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -604,8 +604,10 @@ 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 058a37e6d11c34955ab37f4df9833cdb0166fb6c..fd6e0671f957342e06e0a1601837f221969a01af 100644 --- a/arch/arm/mach-omap2/prm_common.c +++ b/arch/arm/mach-omap2/prm_common.c @@ -523,8 +523,10 @@ void omap_prm_reset_system(void) prm_ll_data->reset_system(); - while (1) + while (1) { cpu_relax(); + wfe(); + } } /**