On 05/22/2014 09:57 AM, Leela Krishna Amudala wrote:
This patch is originally based on commit b3377d186572 ("ARM: 7064/1:
vexpress: Use wfi macro in platform_do_lowpower.")

Current Exynos CPU hotplug code includes a hardcoded WFI
instruction, in ARM encoding.  When the kernel is compiled in Thumb-2
mode, this is invalid and causes the machine to hang hard when a CPU
is offlined.

Use wfi macro instead of the hardcoded WFI instruction.

Is it possible to change it for cpu_do_idle() ?

I guess, that should be backported to the previous kernel version, right ? (Cc stable@).

Thanks
  -- Daniel

Signed-off-by: Leela Krishna Amudala <[email protected]>
---
  arch/arm/mach-exynos/hotplug.c |    8 +-------
  1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/arch/arm/mach-exynos/hotplug.c b/arch/arm/mach-exynos/hotplug.c
index 69fa483..8a134d0 100644
--- a/arch/arm/mach-exynos/hotplug.c
+++ b/arch/arm/mach-exynos/hotplug.c
@@ -46,13 +46,7 @@ static inline void platform_do_lowpower(unsigned int cpu, 
int *spurious)
                if (cpu == 1)
                        exynos_cpu_power_down(cpu);

-               /*
-                * here's the WFI
-                */
-               asm(".word 0xe320f003\n"
-                   :
-                   :
-                   : "memory", "cc");
+               wfi();

                if (pen_release == cpu_logical_map(cpu)) {
                        /*



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