Re: [PATCH 02/27] x86/syscalls: fix -Wmissing-prototypes warnings from COND_SYSCALL()

From: Masahiro Yamada <masahiroy@kernel.org>
To: "Mickaël Salaün" <mic@digikod.net>
Cc: Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	kernel test robot <lkp@intel.com>,
	linux-arch <linux-arch@vger.kernel.org>, X86 ML <x86@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 02/27] x86/syscalls: fix -Wmissing-prototypes warnings from COND_SYSCALL()
Date: Sat, 13 Feb 2021 13:50:52 +0900	[thread overview]
Message-ID: <CAK7LNAS_xG6EAKf8o8wdBD5GBZzajW1P78GfwYgCZ3gO7xCqvg@mail.gmail.com> (raw)
In-Reply-To: <b47407f4-6c4c-1db3-f1ad-c569de315790@digikod.net>

On Sat, Feb 13, 2021 at 12:12 AM Mickaël Salaün <mic@digikod.net> wrote:
>
> Could you please push this patch to Linus? Thanks.
>
> On 04/02/2021 15:16, Mickaël Salaün wrote:
> >
> > On 28/01/2021 01:50, Masahiro Yamada wrote:
> >> Building kernel/sys_ni.c with W=1 omits tons of -Wmissing-prototypes
> >> warnings.
> >>
> >> $ make W=1 kernel/sys_ni.o
> >>   [ snip ]
> >>   CC      kernel/sys_ni.o
> >> In file included from kernel/sys_ni.c:10:
> >> ./arch/x86/include/asm/syscall_wrapper.h:83:14: warning: no previous prototype for '__x64_sys_io_setup' [-Wmissing-prototypes]
> >>    83 |  __weak long __##abi##_##name(const struct pt_regs *__unused) \
> >>       |              ^~
> >> ./arch/x86/include/asm/syscall_wrapper.h:100:2: note: in expansion of macro '__COND_SYSCALL'
> >>   100 |  __COND_SYSCALL(x64, sys_##name)
> >>       |  ^~~~~~~~~~~~~~
> >> ./arch/x86/include/asm/syscall_wrapper.h:256:2: note: in expansion of macro '__X64_COND_SYSCALL'
> >>   256 |  __X64_COND_SYSCALL(name)     \
> >>       |  ^~~~~~~~~~~~~~~~~~
> >> kernel/sys_ni.c:39:1: note: in expansion of macro 'COND_SYSCALL'
> >>    39 | COND_SYSCALL(io_setup);
> >>       | ^~~~~~~~~~~~
> >> ./arch/x86/include/asm/syscall_wrapper.h:83:14: warning: no previous prototype for '__ia32_sys_io_setup' [-Wmissing-prototypes]
> >>    83 |  __weak long __##abi##_##name(const struct pt_regs *__unused) \
> >>       |              ^~
> >> ./arch/x86/include/asm/syscall_wrapper.h:120:2: note: in expansion of macro '__COND_SYSCALL'
> >>   120 |  __COND_SYSCALL(ia32, sys_##name)
> >>       |  ^~~~~~~~~~~~~~
> >> ./arch/x86/include/asm/syscall_wrapper.h:257:2: note: in expansion of macro '__IA32_COND_SYSCALL'
> >>   257 |  __IA32_COND_SYSCALL(name)
> >>       |  ^~~~~~~~~~~~~~~~~~~
> >> kernel/sys_ni.c:39:1: note: in expansion of macro 'COND_SYSCALL'
> >>    39 | COND_SYSCALL(io_setup);
> >>       | ^~~~~~~~~~~~
> >>   ...
> >>
> >> __SYS_STUB0() and __SYS_STUBx() defined a few lines above have forward
> >> declarations. Let's do likewise for __COND_SYSCALL() to fix the
> >> warnings.
> >>
> >> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> >
> > Tested-by: Mickaël Salaün <mic@linux.microsoft.com>
> >
> > Thanks to this patch we avoid multiple emails from Intel's bot when
> > adding new syscalls. :)

Thanks for the reminder.
I will fix the typo "omits" -> "emits"
and send v2 just in case.

> >
> >
> >> ---
> >>
> >>  arch/x86/include/asm/syscall_wrapper.h | 1 +
> >>  1 file changed, 1 insertion(+)
> >>
> >> diff --git a/arch/x86/include/asm/syscall_wrapper.h b/arch/x86/include/asm/syscall_wrapper.h
> >> index a84333adeef2..80c08c7d5e72 100644
> >> --- a/arch/x86/include/asm/syscall_wrapper.h
> >> +++ b/arch/x86/include/asm/syscall_wrapper.h
> >> @@ -80,6 +80,7 @@ extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
> >>      }
> >>
> >>  #define __COND_SYSCALL(abi, name)                                   \
> >> +    __weak long __##abi##_##name(const struct pt_regs *__unused);   \
> >>      __weak long __##abi##_##name(const struct pt_regs *__unused)    \
> >>      {                                                               \
> >>              return sys_ni_syscall();                                \
> >>

-- 
Best Regards
Masahiro Yamada