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

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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>
This commit is contained in:
Nick Bowler 2011-08-24 18:55:37 +01:00 • committed by Russell King
commit b3377d1865
1 changed files with 2 additions and 7 deletions
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9
arch/arm/mach-vexpress/hotplug.c
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@ -13,6 +13,7 @@
#include <linux/smp.h> #include <linux/smp.h>
#include <asm/cacheflush.h> #include <asm/cacheflush.h>
#include <asm/system.h>
extern volatile int pen_release; 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 * code will have already disabled interrupts
*/ */
for (;;) { for (;;) {
/* wfi();
* here's the WFI
*/
asm(".word 0xe320f003\n"
:
:
: "memory", "cc");
if (pen_release == cpu) { if (pen_release == cpu) {
/* /*