From: Borislav Petkov <bp@alien8.de>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Andrew Banman <andrew.banman@hpe.com>,
Dimitri Sivanich <dimitri.sivanich@hpe.com>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Mike Travis <mike.travis@hpe.com>,
"Steven Rostedt (VMware)" <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
Yi Wang <wang.yi59@zte.com.cn>,
linux-acpi@vger.kernel.org
Subject: Re: [PATCH] x86/kernel: Fix more -Wmissing-prototypes warnings
Date: Fri, 7 Dec 2018 20:48:47 +0100 [thread overview]
Message-ID: <20181207194847.GG9385@zn.tnic> (raw)
In-Reply-To: <20181207234210.c29731b7a481c74a4e57220c@kernel.org>
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.
next prev parent reply other threads:[~2018-12-07 19:49 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-05 10:11 [PATCH] x86/kernel: Fix more -Wmissing-prototypes warnings Borislav Petkov
2018-12-05 12:44 ` Rafael J. Wysocki
2018-12-05 13:49 ` Masami Hiramatsu
2018-12-05 14:24 ` Borislav Petkov
2018-12-05 16:25 ` Ingo Molnar
2018-12-05 17:15 ` Borislav Petkov
2018-12-07 14:42 ` Masami Hiramatsu
2018-12-07 19:48 ` Borislav Petkov [this message]
2018-12-08 5:56 ` Masami Hiramatsu
2018-12-08 11:31 ` [tip:x86/cleanups] x86/kprobes: Remove trampoline_handler() prototype tip-bot for Borislav Petkov
2018-12-07 15:21 ` [PATCH] x86/kernel: Fix more -Wmissing-prototypes warnings Masami Hiramatsu
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