[PATCH v2 7/7] arm: LLVMLinux: Use global stack register variable for percpu

From: behanw
Date: Fri Sep 05 2014 - 20:08:04 EST


From: Mark Charlebois <charlebm@xxxxxxxxx>

Using global current_stack_pointer works on both clang and gcc.
current_stack_pointer is an unsigned long and needs to be cast
as a pointer to dereference.

Signed-off-by: Mark Charlebois <charlebm@xxxxxxxxx>
---
arch/arm/include/asm/percpu.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/include/asm/percpu.h b/arch/arm/include/asm/percpu.h
index 209e650..a89b407 100644
--- a/arch/arm/include/asm/percpu.h
+++ b/arch/arm/include/asm/percpu.h
@@ -30,14 +30,14 @@ static inline void set_my_cpu_offset(unsigned long off)
static inline unsigned long __my_cpu_offset(void)
{
unsigned long off;
- register unsigned long *sp asm ("sp");

/*
* Read TPIDRPRW.
* We want to allow caching the value, so avoid using volatile and
* instead use a fake stack read to hazard against barrier().
*/
- asm("mrc p15, 0, %0, c13, c0, 4" : "=r" (off) : "Q" (*sp));
+ asm("mrc p15, 0, %0, c13, c0, 4" : "=r" (off)
+ : "Q" (*(const unsigned long *)current_stack_pointer));

return off;
}
--
1.9.1

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