[PATCH 4/5] arm: LLVMLinux: Use current_stack_pointer in save_stack_trace_tsk

[behanw@converseincode.com]

From: Behan Webster <behanw@converseincode.com>

The existing code uses named registers to get the value of the stack pointer.
The new current_stack_pointer macro is more readable and allows for a central
portable implementation of how to get the stack pointer with ASM.  This change
supports being able to compile the kernel with both gcc and Clang.

Signed-off-by: Mark Charlebois <charlebm@gmail.com>
Signed-off-by: Behan Webster <behanw@converseincode.com>
Reviewed-by: Jan-Simon Möller <dl9pf@gmx.de>
---
 arch/arm/kernel/stacktrace.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
index 00f79e5..8c23310 100644
--- a/arch/arm/kernel/stacktrace.c
+++ b/arch/arm/kernel/stacktrace.c
@@ -109,11 +109,9 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
 		frame.pc = thread_saved_pc(tsk);
 #endif
 	} else {
-		register unsigned long current_sp asm ("sp");
-
 		data.no_sched_functions = 0;
 		frame.fp = (unsigned long)__builtin_frame_address(0);
-		frame.sp = current_sp;
+		frame.sp = current_stack_pointer;
 		frame.lr = (unsigned long)__builtin_return_address(0);
 		frame.pc = (unsigned long)save_stack_trace_tsk;
 	}
-- 
1.8.1.2