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@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index 9a0ac85..f976211 100644 (file)
--- 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 (file)
--- 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;