linux-kernel - [PATCH 2/2] tracing/function-return-tracer: Call prepare_ftrace

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Date:	Wed, 12 Nov 2008 22:49:23 +0100
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	Ingo Molnar <mingo@...e.hu>
CC:	Steven Rostedt <rostedt@...dmis.org>,
	Linux Kernel <linux-kernel@...r.kernel.org>
Subject: [PATCH 2/2] tracing/function-return-tracer: Call prepare_ftrace_return
 by registers

Impact: Optimize a bit the function return tracer

This patch changes the calling convention of prepare_ftrace_return
to pass its arguments by register. This will optimize it a bit and
prepare it to support dynamic tracing.

Signed-off-by: Frederic Weisbecker <fweisbec@...il.com>
Cc: Steven Rostedt <rostedt@...dmis.org>
---
 arch/x86/kernel/entry_32.S |    5 +----
 arch/x86/kernel/ftrace.c   |    1 -
 2 files changed, 1 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index 9a0ac85..f976211 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -1217,12 +1217,9 @@ trace_return:
 	pushl %eax
 	pushl %ecx
 	pushl %edx
-	movl 0xc(%esp), %eax
-	pushl %eax
+	movl 0xc(%esp), %edx
 	lea 0x4(%ebp), %eax
-	pushl %eax
 	call prepare_ftrace_return
-	addl $8, %esp
 	popl %edx
 	popl %ecx
 	popl %eax
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 1db0e12..fe83273 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -95,7 +95,6 @@ unsigned long ftrace_return_to_handler(void)
  * Hook the return address and push it in the stack of return addrs
  * in current thread info.
  */
-asmlinkage
 void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
 {
 	unsigned long old;
-- 
1.5.2.5
--
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