tree 7cf891feaa8224363173a3c9cb1fa8d0c472d101
parent f6bc87c39d52b2b7aa83f16fcee46daefd26cd4d
author Steve Capper <steve.capper@linaro.org> 1367508342 +0100
committer Steve Capper <steve.capper@linaro.org> 1371199366 +0100

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>