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From:   Masahiro Yamada <masahiroy@kernel.org>
Date:   Thu, 28 Jan 2021 09:55:30 +0900
Message-ID: <CAK7LNATkX6=FNsMu0X44u0FSYYhW7iGfPq9cY43TReFCSdrsUg@mail.gmail.com>
Subject: Re: [PATCH 02/27] x86/syscalls: fix -Wmissing-prototypes warnings
 from COND_SYSCALL()
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On Thu, Jan 28, 2021 at 9:52 AM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> Building kernel/sys_ni.c with W=1 omits tons of -Wmissing-prototypes


This is a typo.  "omits" -> "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)    \
>         {                                                               \
>                 return sys_ni_syscall();                                \
> --
> 2.27.0
>


-- 
Best Regards
Masahiro Yamada