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Subject: Re: [PATCH] fixup! signal: factor copy_siginfo_to_external32 from
 copy_siginfo_to_user32
To:     Arnd Bergmann <arnd@arndb.de>, Christoph Hellwig <hch@lst.de>
Cc:     Jeremy Kerr <jk@ozlabs.org>, linux-kernel@vger.kernel.org,
        "Eric W . Biederman" <ebiederm@xmission.com>,
        linux-fsdevel@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>,
        linuxppc-dev@lists.ozlabs.org,
        Alexander Viro <viro@zeniv.linux.org.uk>
References: <20200428074827.GA19846@lst.de>
 <20200428195645.1365019-1-arnd@arndb.de>
From:   Christophe Leroy <christophe.leroy@c-s.fr>
Message-ID: <d00b4436-9a97-5e90-2a6f-e79f90be9736@c-s.fr>
Date:   Wed, 29 Apr 2020 08:17:22 +0200
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Le 28/04/2020 à 21:56, Arnd Bergmann a écrit :
> I think I found a way to improve the x32 handling:
> 
> This is a simplification over Christoph's "[PATCH 2/7] signal: factor
> copy_siginfo_to_external32 from copy_siginfo_to_user32", reducing the
> x32 specifics in the common code to a single #ifdef/#endif check, in
> order to keep it more readable for everyone else.
> 
> Christoph, if you like it, please fold into your patch.
> 
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Alexander Viro <viro@zeniv.linux.org.uk>
> Cc: Jeremy Kerr <jk@ozlabs.org>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: "Eric W . Biederman" <ebiederm@xmission.com>
> Cc: linuxppc-dev@lists.ozlabs.org
> Cc: linux-fsdevel@vger.kernel.org
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>   arch/x86/include/asm/compat.h | 10 ++++++++++
>   arch/x86/kernel/signal.c      | 23 +++++++++++++++++++++++
>   kernel/signal.c               | 15 ++-------------
>   3 files changed, 35 insertions(+), 13 deletions(-)
> 

[...]

> diff --git a/kernel/signal.c b/kernel/signal.c
> index 1a81602050b4..935facca4860 100644
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -3318,29 +3318,18 @@ void copy_siginfo_to_external32(struct compat_siginfo *to,
>   	}
>   }
>   
> +#ifndef CONFIG_X86_X32_ABI

Can it be declared __weak instead of enclosing it in an #ifndef ?

>   int copy_siginfo_to_user32(struct compat_siginfo __user *to,
>   			   const struct kernel_siginfo *from)
> -#if defined(CONFIG_X86_X32_ABI) || defined(CONFIG_IA32_EMULATION)
> -{
> -	return __copy_siginfo_to_user32(to, from, in_x32_syscall());
> -}
> -int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
> -			     const struct kernel_siginfo *from, bool x32_ABI)
> -#endif
>   {
>   	struct compat_siginfo new;
>   
>   	copy_siginfo_to_external32(&new, from);
> -#ifdef CONFIG_X86_X32_ABI
> -	if (x32_ABI && from->si_signo == SIGCHLD) {
> -		new._sifields._sigchld_x32._utime = from->si_utime;
> -		new._sifields._sigchld_x32._stime = from->si_stime;
> -	}
> -#endif
>   	if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
>   		return -EFAULT;
>   	return 0;
>   }
> +#endif
>   
>   static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
>   					 const struct compat_siginfo *from)
> 

Christophe