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

Sergei Shtylyov
2021-01-28T07:59:07Z

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