From: Michael Ellerman <mpe@ellerman.id.au>
Date: Tue, 10 Jun 2014 06:46:21 +0000 (+1000)
Subject: powerpc/perf: Ensure all EBB register state is cleared on fork()
X-Git-Tag: omap-for-v3.16/fixes-against-rc1~30^2~20
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3df48c981d5a9610e02e9270b1bc4274fb536710;p=pandora-kernel.git

powerpc/perf: Ensure all EBB register state is cleared on fork()

In commit 330a1eb "Core EBB support for 64-bit book3s" I messed up
clear_task_ebb(). It clears some but not all of the task's Event Based
Branch (EBB) registers when we duplicate a task struct.

That allows a child task to observe the EBBHR & EBBRR of its parent,
which it should not be able to do.

Fix it by clearing EBBHR & EBBRR.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: stable@vger.kernel.org [v3.11+]
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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