Re: [PATCH 4/5] ftrace: clean up function graph asm

Frédéric Weisbecker
2008-12-02T21:24:57Z

2008/12/2 Steven Rostedt <rostedt@goodmis.org>:
> From: Steven Rostedt <srostedt@redhat.com>
>
> Impact: clean up
>
> There exists macros for x86 asm to handle x86_64 and i386.
> This patch updates function graph asm to use them.
>
> Signed-off-by: Steven Rostedt <srostedt@redhat.com>
> ---
> arch/x86/kernel/ftrace.c | 20 ++++----------------
> 1 files changed, 4 insertions(+), 16 deletions(-)
>
> diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
> index 5883247..1a5b8f8 100644
> --- a/arch/x86/kernel/ftrace.c
> +++ b/arch/x86/kernel/ftrace.c
> @@ -467,28 +467,16 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
> * ignore such a protection.
> */
> asm volatile(
> -#ifdef CONFIG_X86_64
> - "1: movq (%[parent_old]), %[old]\n"
> - "2: movq %[return_hooker], (%[parent_replaced])\n"
> -#else
> - "1: movl (%[parent_old]), %[old]\n"
> - "2: movl %[return_hooker], (%[parent_replaced])\n"
> -#endif
> + "1: " _ASM_MOV " (%[parent_old]), %[old]\n"
> + "2: " _ASM_MOV " %[return_hooker], (%[parent_replaced])\n"
> " movl $0, %[faulted]\n"
>
> ".section .fixup, \"ax\"\n"
> "3: movl $1, %[faulted]\n"
> ".previous\n"
>
> - ".section __ex_table, \"a\"\n"
> -#ifdef CONFIG_X86_64
> - " .quad 1b, 3b\n"
> - " .quad 2b, 3b\n"
> -#else
> - " .long 1b, 3b\n"
> - " .long 2b, 3b\n"
> -#endif
> - ".previous\n"
> + _ASM_EXTABLE(1b, 3b)
> + _ASM_EXTABLE(2b, 3b)
>
> : [parent_replaced] "=r" (parent), [old] "=r" (old),
> [faulted] "=r" (faulted)
> --

Thanks Steven. I wasn't aware of _ASM_MOV.