From mboxrd@z Thu Jan  1 00:00:00 1970
From: will.deacon@arm.com (Will Deacon)
Date: Tue, 22 Apr 2014 10:44:24 +0100
Subject: [PATCH] ARM: fix string functions on !MMU
In-Reply-To: <1398103808-24380-1-git-send-email-rabin@rab.in>
References: <1398103808-24380-1-git-send-email-rabin@rab.in>
Message-ID: <20140422094424.GA6979@arm.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Mon, Apr 21, 2014 at 07:10:08PM +0100, Rabin Vincent wrote:
> 8c56cc8be5b38e ("ARM: 7449/1: use generic strnlen_user and
> strncpy_from_user functions") apparently broken those string operations
> for !MMU.  USER_DS == KERNEL_DS on !MMU, so user_addr_max() always
> restricts the addresses to TASK_SIZE.
> 
> TASK_SIZE has anyway no meaning on !MMU, so make user_addr_max() not
> restrict anything.

Might be worth mentioning that this is an issue because KERNEL_DS is 0x0
(since it's a 32-bit quantity), so checks like addr < user_addr_max() will
fail. Anyway, the code looks fine to me:

  Acked-by: Will Deacon <will.deacon@arm.com>

Will