linux-kernel - Re: [PATCH 02/27] x86/syscalls: fix -Wmissing-prototypes warnings from COND

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Message-ID: <b47407f4-6c4c-1db3-f1ad-c569de315790@digikod.net>
Date:   Fri, 12 Feb 2021 16:13:24 +0100
From:   Mickaël Salaün <mic@...ikod.net>
To:     Masahiro Yamada <masahiroy@...nel.org>
Cc:     linux-kbuild@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel test robot <lkp@...el.com>,
        linux-arch@...r.kernel.org, x86@...nel.org,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH 02/27] x86/syscalls: fix -Wmissing-prototypes warnings
 from COND_SYSCALL()

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@...nel.org>
> 
> Tested-by: Mickaël Salaün <mic@...ux.microsoft.com>
> 
> Thanks to this patch we avoid multiple emails from Intel's bot when
> adding new syscalls. :)
> 
> 
>> ---
>>
>>  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();				\
>>