[PATCH] arch/blackfin/kernel/stacktrace.c: Use __builtin_frame_address instead of asm("FP")

[Chen Gang]

>From 97df54f9625dae3c61f65e1f0da794718262cd69 Mon Sep 17 00:00:00 2001
From: Chen Gang <gang.chen.5i5j@xxxxxxxxx>
Date: Tue, 13 Oct 2015 23:24:02 +0800
Subject: [PATCH] arch/blackfin/kernel/stacktrace.c: Use __builtin_frame_address instead of asm("FP")

When latest gcc build kernel with "-fno-omit-frame-pointer -pg", it will
cause building break. For getting address on the stack, kernel need to
use __builtin_frame_address instead of. The related error:

    CC      arch/blackfin/kernel/stacktrace.o
  arch/blackfin/kernel/stacktrace.c: In function 'save_stack_trace':
  arch/blackfin/kernel/stacktrace.c:23:6: error: frame pointer required, but reserved
   void save_stack_trace(struct stack_trace *trace)
        ^
  arch/blackfin/kernel/stacktrace.c:13:24: note: for 'current_frame_pointer'
   register unsigned long current_frame_pointer asm("FP");
                          ^

Signed-off-by: Chen Gang <gang.chen.5i5j@xxxxxxxxx>
---
 arch/blackfin/kernel/stacktrace.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/blackfin/kernel/stacktrace.c b/arch/blackfin/kernel/stacktrace.c
index 30301e1..1d48aee 100644
--- a/arch/blackfin/kernel/stacktrace.c
+++ b/arch/blackfin/kernel/stacktrace.c
@@ -10,8 +10,6 @@
 #include <linux/thread_info.h>
 #include <linux/module.h>
 
-register unsigned long current_frame_pointer asm("FP");
-
 struct stackframe {
 	unsigned long fp;
 	unsigned long rets;
@@ -29,7 +27,7 @@ void save_stack_trace(struct stack_trace *trace)
 
 	low = (unsigned long)task_stack_page(current);
 	high = low + THREAD_SIZE;
-	fp = current_frame_pointer;
+	fp = (unsigned long)__builtin_frame_address(0);
 
 	while (fp>= low && fp <= (high - sizeof(*frame))) {
 		frame = (struct stackframe *)fp;
-- 
1.9.3

Attachment: 0001-arch-blackfin-kernel-stacktrace.c-Use-__builtin_fram.patch
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