From 0b2d10f8f2e686c9f4b718251765f09f77ee8088 Mon Sep 17 00:00:00 2001
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Date: Tue, 1 Oct 2013 17:11:35 +1000
Subject: [PATCH] powerpc: Restore registers on error exit from
 csum_partial_copy_generic()

commit 8f21bd0090052e740944f9397e2be5ac7957ded7 upstream.

The csum_partial_copy_generic() function saves the PowerPC non-volatile
r14, r15, and r16 registers for the main checksum-and-copy loop.
Unfortunately, it fails to restore them upon error exit from this loop,
which results in silent corruption of these registers in the presumably
rare event of an access exception within that loop.

This commit therefore restores these register on error exit from the loop.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[bwh: Backported to 3.2: register name macros use lower-case 'r']
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
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