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-rw-r--r--arch/arm/include/asm/barrier.h2
-rw-r--r--arch/arm/include/asm/processor.h6
-rw-r--r--arch/arm/kernel/machine_kexec.c5
-rw-r--r--arch/arm/kernel/smp.c4
-rw-r--r--arch/arm/mach-omap2/prm_common.c4
5 files changed, 17 insertions, 4 deletions
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 120f4c9bbfde..57fe73ea0f72 100644
--- a/arch/arm/include/asm/processor.h
+++ b/arch/arm/include/asm/processor.h
@@ -89,7 +89,11 @@ 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 dd2eb5f76b9f..76300f3813e8 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 3bf82232b1be..7f0b99e1fff3 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 058a37e6d11c..fd6e0671f957 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();
+ }
}
/**