Re: [PATCH v2 1/2] arm64: implement FTRACE_WITH_REGS

[Steven Rostedt]

On Sat, 9 Jul 2016 11:06:32 +0200
Torsten Duwe <d...@lst.de> wrote:


> Maybe the code in question can be replaced with the change below, now that
> there is a preprocessor define in V2?
> (untested)
> 
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index 3f743b1..695a646 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -2423,6 +2423,12 @@ ftrace_code_disable(struct module *mod, struct 
> dyn_ftrace *rec)
>       if (unlikely(ftrace_disabled))
>               return 0;
>  
> +#ifdef CC_USING_PROLOG_PAD
> +     /* If the compiler already generated NOPs instead of
> +      * calls to mcount, we're done here.
> +     */
> +     return 1;
> +#endif

I really hate adding #ifdef's like this in generic code if the arch can
handle it with some other means.

-- Steve


>       ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
>       if (ret) {
>               ftrace_bug(ret, rec);