From: Michael Neuling <mikey@neuling.org>
Date: Thu, 26 Sep 2013 03:29:09 +0000 (+1000)
Subject: powerpc/tm: Switch out userspace PPR and DSCR sooner
X-Git-Tag: v3.12-rc4~24^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e9bdc3d6143d1c4b8d8ce5231fc958268331f983;p=pandora-kernel.git

powerpc/tm: Switch out userspace PPR and DSCR sooner

When we do a treclaim or trecheckpoint we end up running with userspace
PPR and DSCR values.  Currently we don't do anything special to avoid
running with user values which could cause a severe performance
degradation.

This patch moves the PPR and DSCR save and restore around treclaim and
trecheckpoint so that we run with user values for a much shorter period.
More care is taken with the PPR as it's impact is greater than the DSCR.

This is similar to user exceptions, where we run HTM_MEDIUM early to
ensure that we don't run with a userspace PPR values in the kernel.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Cc: <stable@vger.kernel.org> # 3.9+
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---

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