From: Steve Capper <steve.capper@linaro.org>
Date: Thu, 2 May 2013 15:25:42 +0000 (+0100)
Subject: ARM64: mm: Make PAGE_NONE pages read only and no-execute.
X-Git-Tag: omap-for-v3.11/fixes-for-merge-window~40^2^2~4
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=072b1b62a6436b71ab951faae4500db2fbed63de;p=pandora-kernel.git

ARM64: mm: Make PAGE_NONE pages read only and no-execute.

If we consider the following code sequence:

	my_pte = pte_modify(entry, myprot);
	x = pte_write(my_pte);
	y = pte_exec(my_pte);

If myprot comes from a PROT_NONE page, then x and y will both be
true which is undesireable behaviour.

This patch sets the no-execute and read-only bits for PAGE_NONE
such that the code above will return false for both x and y.

Signed-off-by: Steve Capper <steve.capper@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
---

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