arm64: LLVMLinux: Add current_stack_pointer() for arm64

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 <[email protected]>
Reviewed-by: Jan-Simon Möller <[email protected]>
Reviewed-by: Mark Charlebois <[email protected]>
Reviewed-by: Olof Johansson <[email protected]>
Acked-by: Will Deacon <[email protected]>
Signed-off-by: Will Deacon <[email protected]>

1 files changed, 5 insertions, 0 deletions

diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index 45108d802f5e..356e03774df4 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__;