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SubjectRe: [PATCH] x86/kernel: Fix more -Wmissing-prototypes warnings
On Fri, Dec 07, 2018 at 11:42:10PM +0900, Masami Hiramatsu wrote:
> 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)

I just tried two gcc versions: 8.2 and 4.8.5. Both asms looks good:

ffffffff81044690 <kretprobe_trampoline>:
...


ffffffff810446ab: 41 57 push %r15
ffffffff810446ad: 48 89 e7 mov %rsp,%rdi
ffffffff810446b0: e8 db 01 00 00 callq ffffffff81044890 <trampoline_handler>

there's the CALL...

ffffffff810446b5: 48 89 84 24 98 00 00 mov %rax,0x98(%rsp)
ffffffff810446bc: 00

... and the handler is at the expected address.

ffffffff81044890 <trampoline_handler>:
ffffffff81044890: e8 ab c9 7b 00 callq ffffffff81801240 <__fentry__>
ffffffff81044895: 41 57 push %r15
ffffffff81044897: 41 56 push %r14
ffffffff81044899: 41 55 push %r13
ffffffff8104489b: 49 89 fd mov %rdi,%r13

Dunno, if you feel like there might be some trouble with some compilers,
I can keep the hunk below as a separate patch and revert it when it
explodes somewhere...?

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

--
Regards/Gruss,
Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.

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