[PATCH V2 1/6] arm64: LLVMLinux: Add current_stack_pointer() for arm64

From: behanw
Date: Wed Aug 27 2014 - 00:29:51 EST

From: Behan Webster <behanw@xxxxxxxxxxxxxxxxxx>

Define a global named register for current_stack_pointer. The use of this new
variable guarantees that both gcc and clang can access this register in C code.

Signed-off-by: Behan Webster <behanw@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Jan-Simon MÃller <dl9pf@xxxxxx>
Reviewed-by: Mark Charlebois <charlebm@xxxxxxxxx>
Reviewed-by: Olof Johansson <olof@xxxxxxxxx>
Acked-by: Will Deacon <will.deacon@xxxxxxx>
arch/arm64/include/asm/thread_info.h | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index 45108d8..356e037 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -69,6 +69,11 @@ struct thread_info {
#define init_stack (init_thread_union.stack)

+ * how to get the current stack pointer from C
+ */
+register unsigned long current_stack_pointer asm ("sp");
* how to get the thread information struct from C
static inline struct thread_info *current_thread_info(void) __attribute_const__;

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