From aa512a27e9e8ed32f31b15eec67ab1ceca33839b Mon Sep 17 00:00:00 2001
From: Steven Rostedt <srostedt@redhat.com>
Date: Wed, 13 May 2009 13:52:19 -0400
Subject: x86/function-graph: fix constraint for recording old return value

After upgrading from gcc 4.2.2 to 4.4.0, the function graph tracer broke.
Investigating, I found that in the asm that replaces the return value,
gcc was using the same register for the old value as it was for the
new value.

	mov	(addr), old
	mov	new, (addr)

But if old and new are the same register, we clobber new with old!
I first thought this was a bug in gcc 4.4.0 and reported it:

  http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40132

Andrew Pinski responded (quickly), saying that it was correct gcc behavior
and the code needed to denote old as an "early clobber".

Instead of "=r"(old), we need "=&r"(old).

[Impact: keep function graph tracer from breaking with gcc 4.4.0 ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 18dfa30..b79c553 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -442,7 +442,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
 		_ASM_EXTABLE(1b, 4b)
 		_ASM_EXTABLE(2b, 4b)
 
-		: [old] "=r" (old), [faulted] "=r" (faulted)
+		: [old] "=&r" (old), [faulted] "=r" (faulted)
 		: [parent] "r" (parent), [return_hooker] "r" (return_hooker)
 		: "memory"
 	);
-- 
cgit v0.10.2


From 88fc86c283d9c3854e67e4155808027bc2519eb6 Mon Sep 17 00:00:00 2001
From: GeunSik Lim <leemgs1@gmail.com>
Date: Thu, 14 May 2009 17:23:38 +0900
Subject: tracing: Append prompt in /debug/tracing/README file

append prompt in /debug/tracing/README file.

This is trivial issue. Fix typo Mini Howto file(README) for ftrace.

[ Impact: cleanup ]

Signed-off-by: GeunSik Lim <geunsik.lim@samsung.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: williams <williams@redhat.com>
LKML-Reference: <1242289418.31161.45.camel@centos51>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index a884c09..cda81ec 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2380,7 +2380,7 @@ static const char readme_msg[] =
 	"# echo print-parent > /debug/tracing/trace_options\n"
 	"# echo 1 > /debug/tracing/tracing_enabled\n"
 	"# cat /debug/tracing/trace > /tmp/trace.txt\n"
-	"echo 0 > /debug/tracing/tracing_enabled\n"
+	"# echo 0 > /debug/tracing/tracing_enabled\n"
 ;
 
 static ssize_t
-- 
cgit v0.10.2