From: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Date: Tue, 1 Oct 2013 19:04:10 +0000 (+0530)
Subject: powerpc/sysfs: Disable writing to PURR in guest mode
X-Git-Tag: v3.2.52~52
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=28cfcc851d5c8a7075ea8bb9b8695bb376f6872d;p=pandora-kernel.git

powerpc/sysfs: Disable writing to PURR in guest mode

commit d1211af3049f4c9c1d8d4eb8f8098cc4f4f0d0c7 upstream.

arch/powerpc/kernel/sysfs.c exports PURR with write permission.
This may be valid for kernel in phyp mode. But writing to
the file in guest mode causes crash due to a priviledge violation

Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[bwh: Backported to 3.2:
 - Adjust context
 - CPUs are sysdev and we must use the sysdev API]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

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