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Message-ID: <4CD03817.4050907@mvista.com>
Date:   Tue, 02 Nov 2010 19:11:03 +0300
From:   Sergei Shtylyov <sshtylyov@mvista.com>
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To:     David Daney <ddaney@caviumnetworks.com>
CC:     linux-mips@linux-mips.org, ralf@linux-mips.org,
        Camm Maguire <camm@maguirefamily.org>
Subject: Re: [PATCH 2/2] MIPS: Don't clobber personality bits in 32-bit sys_personality().
References: <1288658588-26801-1-git-send-email-ddaney@caviumnetworks.com> <1288658588-26801-2-git-send-email-ddaney@caviumnetworks.com>
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Hello.

David Daney wrote:

> If PER_LINUX32 has been set on a 32-bit kernel, only twiddle with the
> low-order personality bits, let the upper bits pass through.

> Signed-off-by: David Daney <ddaney@caviumnetworks.com>
> Cc: Camm Maguire <camm@maguirefamily.org>
> ---
>  arch/mips/kernel/linux32.c |   12 ++++++------
>  1 files changed, 6 insertions(+), 6 deletions(-)

> diff --git a/arch/mips/kernel/linux32.c b/arch/mips/kernel/linux32.c
> index 6343b4a..a63f4e2 100644
> --- a/arch/mips/kernel/linux32.c
> +++ b/arch/mips/kernel/linux32.c
> @@ -252,13 +252,13 @@ SYSCALL_DEFINE5(n32_msgrcv, int, msqid, u32, msgp, size_t, msgsz,
>  SYSCALL_DEFINE1(32_personality, unsigned long, personality)
>  {
>  	int ret;
> -	personality &= 0xffffffff;
> +	unsigned int p = personality & 0xffffffff;

    I'd have inserted an empty line here...

>  	if (personality(current->personality) == PER_LINUX32 &&
> -	    personality == PER_LINUX)
> -		personality = PER_LINUX32;
> -	ret = sys_personality(personality);
> -	if (ret == PER_LINUX32)
> -		ret = PER_LINUX;
> +	    personality(p) == PER_LINUX)
> +		p = (p & ~PER_MASK) | PER_LINUX32;
> +	ret = sys_personality(p);
> +	if (ret != -1 && personality(ret) == PER_LINUX32)
> +		ret = (ret & ~PER_MASK) | PER_LINUX;
>  	return ret;
>  }

WBR, Sergei