Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH 02/27] x86/syscalls: fix -Wmissing-prototypes warnings
 from COND_SYSCALL()
To:     Masahiro Yamada <masahiroy@kernel.org>, linux-arch@vger.kernel.org,
        x86@kernel.org
Cc:     linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org,
        linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org,
        linux-sh@vger.kernel.org, linux-um@lists.infradead.org,
        linux-xtensa@linux-xtensa.org, linuxppc-dev@lists.ozlabs.org,
        sparclinux@vger.kernel.org
References: <20210128005110.2613902-1-masahiroy@kernel.org>
 <20210128005110.2613902-3-masahiroy@kernel.org>
From:   Sergei Shtylyov <sergei.shtylyov@gmail.com>
Organization: Brain-dead Software
Message-ID: <dd37a7f2-55e1-2e96-0c93-4a40980b8ef2@gmail.com>
Date:   Thu, 28 Jan 2021 10:59:07 +0300
User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:78.0) Gecko/20100101
 Thunderbird/78.6.1
MIME-Version: 1.0
In-Reply-To: <20210128005110.2613902-3-masahiroy@kernel.org>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

Hello!

On 28.01.2021 3:50, Masahiro Yamada wrote:

> Building kernel/sys_ni.c with W=1 omits tons of -Wmissing-prototypes

    Emits?

> 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>
> ---
> 
>   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)	\

    Aren't these two lines identical?

[...]

MBR, Sergei