linux-kernel - Re: [PATCH] x86/kernel: Fix more -Wmissing-prototypes warnings

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Date:   Fri, 7 Dec 2018 23:42:10 +0900
From:   Masami Hiramatsu <mhiramat@...nel.org>
To:     Borislav Petkov <bp@...en8.de>
Cc:     Ingo Molnar <mingo@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Andrew Banman <andrew.banman@....com>,
        Dimitri Sivanich <dimitri.sivanich@....com>,
        "H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>,
        Mike Travis <mike.travis@....com>,
        "Steven Rostedt (VMware)" <rostedt@...dmis.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Yi Wang <wang.yi59@....com.cn>, linux-acpi@...r.kernel.org
Subject: Re: [PATCH] x86/kernel: Fix more -Wmissing-prototypes warnings

Hi,

On Wed, 5 Dec 2018 18:15:47 +0100
Borislav Petkov <bp@...en8.de> wrote:

> On Wed, Dec 05, 2018 at 05:25:26PM +0100, Ingo Molnar wrote:
> > Also, preferably the prototype should be eliminated via proper ordering 
> > of functions from lower level to higher levels.
> 
> Well, that trampoline_handler() is special as we call it from inline asm
> and I see Masami has marked it __visible etc.
> 
> So doing this below still builds and the trampoline_handler doesn't get
> discarded but maybe there's a reason for it not being static.
> 
> Masami?

Hmm, I just thought that the symbol only referred from inline asm should
be visible. But if it is OK for any version of supported gcc and clang,
I'm good to remove it. :-) (IOW, I just concerned about older gcc)

Reviewed-by: Masami Hiramatsu <mhiramat@...nel.org>

Thank you,

> 
> ---
> diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
> index 6480056d370f..308bf103cc73 100644
> --- a/arch/x86/kernel/kprobes/core.c
> +++ b/arch/x86/kernel/kprobes/core.c
> @@ -66,8 +66,6 @@
>  
>  #include "common.h"
>  
> -void *trampoline_handler(struct pt_regs *regs);
> -
>  DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
>  DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
>  
> @@ -753,7 +751,7 @@ STACK_FRAME_NON_STANDARD(kretprobe_trampoline);
>  /*
>   * Called from kretprobe_trampoline
>   */
> -__visible __used void *trampoline_handler(struct pt_regs *regs)
> +static __used void *trampoline_handler(struct pt_regs *regs)
>  {
>  	struct kretprobe_instance *ri = NULL;
>  	struct hlist_head *head, empty_rp;
> 
> -- 
> Regards/Gruss,
>     Boris.
> 
> Good mailing practices for 400: avoid top-posting and trim the reply.


-- 
Masami Hiramatsu <mhiramat@...nel.org>