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SubjectRe: [PATCH] ftrace/x86: Fix missing ops arg on static function tracing
On Sat, 14 Nov 2015 18:32:28 +0900
Namhyung Kim <namhyung@kernel.org> wrote:

> The commit f1ab00af816e ("ftrace/x86: Get rid of ftrace_caller_setup")
> moved code that loads ftrace_ops into 3rd parameter but it missed to do
> for static tracing.
>
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> ---
> arch/x86/kernel/mcount_64.S | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/x86/kernel/mcount_64.S b/arch/x86/kernel/mcount_64.S
> index 94ea120fa21f..6c1ccf9e5427 100644
> --- a/arch/x86/kernel/mcount_64.S
> +++ b/arch/x86/kernel/mcount_64.S
> @@ -278,6 +278,9 @@ trace:
> /* save_mcount_regs fills in first two parameters */
> save_mcount_regs
>
> + /* Load the ftrace_ops into the 3rd parameter */
> + movq function_trace_op(%rip), %rdx
> +
> call *ftrace_trace_function

This isn't needed, nor will the parameter be used if added. A comment
should probably be added here instead.

/*
* When DYNAMIC_FTRACE is not defined, ARCH_SUPPORTS_FTRACE_OPS is not
* set (see include/asm/ftrace.h). Only the ip and parent ip are used
* and the list function is called when function tracing is enabled.
*/

-- Steve

>
> restore_mcount_regs



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