From: Segher Boessenkool <segher@kernel.crashing.org>
Date: Tue, 19 Jun 2007 15:07:04 +0000 (+1000)
Subject: [POWERPC] PowerPC: Prevent data exception in kernel space (32-bit)
X-Git-Tag: v2.6.22-rc6~72^2~1
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9ba4ace39fdfe22268daca9f28c5df384ae462cf;p=pandora-kernel.git

[POWERPC] PowerPC: Prevent data exception in kernel space (32-bit)

The "is_exec" branch of the protection check in do_page_fault()
didn't do anything on 32-bit PowerPC.  So if a userland program
jumps to a page with Linux protection flags "---p", all the tests
happily fall through, and handle_mm_fault() is called, which in
turn calls handle_pte_fault(), which calls update_mmu_cache(),
which goes flush the dcache to a page with no access rights.

Boom.

This fixes it.

Signed-off-by: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
---

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