From: Anton Blanchard <anton@samba.org>
Date: Wed, 4 Apr 2012 18:24:29 +0000 (+0000)
Subject: powerpc: No need to save XER in a system call
X-Git-Tag: v3.5-rc1~132^2~56
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=823df43552da39fd48a2dd74949363a1c8cf62bb;p=pandora-kernel.git

powerpc: No need to save XER in a system call

The XER is a volatile register so there is no need to save and restore
it over a system call - zero it out in the exception stack frame
instead.

This should fix a 5 cycle stall of the mfxer/std seen on POWER7.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---

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