ARM: 7064/1: vexpress: Use wfi macro in platform_do_lowpower.

Current Versatile Express 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.

Using the wfi macro (which uses the appropriate assembler mnemonic)
causes the correct instruction to be emitted in either case.  As a
consequence of this change, an apparently vestigial "cc" clobber is
dropped from the asm (the macro uses "memory" only).

Signed-off-by: Nick Bowler <nbowler@elliptictech.com>
Reviewed-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 2 insertions, 7 deletions

diff --git a/arch/arm/mach-vexpress/hotplug.c b/arch/arm/mach-vexpress/hotplug.c
index ea4cbfb90a66..3668cf91d2de 100644
--- a/arch/arm/mach-vexpress/hotplug.c
+++ b/arch/arm/mach-vexpress/hotplug.c
@@ -13,6 +13,7 @@
 #include <linux/smp.h>
 
 #include <asm/cacheflush.h>
+#include <asm/system.h>
 
 extern volatile int pen_release;
 
@@ -62,13 +63,7 @@ static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
          * code will have already disabled interrupts
          */
         for (;;) {
-                /*
-                 * here's the WFI
-                 */
-                asm(".word      0xe320f003\n"
-                    :
-                    :
-                    : "memory", "cc");
+                wfi();
 
                 if (pen_release == cpu) {
                         /*