linux-kernel - Re: [PATCH v2] powerpc: fix personality handling in ppc64

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Date:	Wed, 05 Sep 2012 12:54:03 +1000
From:	Benjamin Herrenschmidt <benh@...nel.crashing.org>
To:	Jiri Kosina <jkosina@...e.cz>
Cc:	Andreas Schwab <schwab@...ux-m68k.org>,
	Paul Mackerras <paulus@...ba.org>,
	linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] powerpc: fix personality handling in
 ppc64_personality()

On Thu, 2012-08-02 at 09:10 +0200, Jiri Kosina wrote:
> Directly comparing current->personality against PER_LINUX32 doesn't work
> in cases when any of the personality flags stored in the top three bytes
> are used.
> 
> Directly forcefully setting personality to PER_LINUX32 or PER_LINUX
> discards any flags stored in the top three bytes
> 
> Use personality() macro to compare only PER_MASK bytes and make sure that
> we are setting only the bits that should be set, instead of
> overwriting the whole value.
> 
> Signed-off-by: Jiri Kosina <jkosina@...e.cz>
> ---
> 
> changed since v1: fix the bit ops to reflect the fact that PER_LINUX is 
> actually 0

Had already merged v1 (oops.. didn't spot the issue with PER_LINUX being
0). Can you send an incremental fixup ?

Cheers,
Ben.

>  arch/powerpc/kernel/syscalls.c |    8 ++++----
>  1 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/syscalls.c b/arch/powerpc/kernel/syscalls.c
> index f2496f2..dc1558e 100644
> --- a/arch/powerpc/kernel/syscalls.c
> +++ b/arch/powerpc/kernel/syscalls.c
> @@ -107,11 +107,11 @@ long ppc64_personality(unsigned long personality)
>  	long ret;
>  
>  	if (personality(current->personality) == PER_LINUX32
> -	    && personality == PER_LINUX)
> -		personality = PER_LINUX32;
> +	    && personality(personality) == PER_LINUX)
> +		personality |= PER_LINUX32;
>  	ret = sys_personality(personality);
> -	if (ret == PER_LINUX32)
> -		ret = PER_LINUX;
> +	if (personality(ret) == PER_LINUX32)
> +		ret &= ~PER_LINUX32;
>  	return ret;
>  }
>  #endif
> -- 
> 1.7.3.1
> 


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