powerpc: Handle unaligned ldbrx/stdbrx
authorAnton Blanchard <anton@samba.org>
Tue, 6 Aug 2013 16:01:19 +0000 (02:01 +1000)
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>
Wed, 14 Aug 2013 01:50:20 +0000 (11:50 +1000)
commit230aef7a6a23b6166bd4003bfff5af23c9bd381f
treea7c3b41dc06504c87a7f952d2232a567b43fda5f
parent5b63fee1fe5d10c397d740ffef4d576a196ed72d
powerpc: Handle unaligned ldbrx/stdbrx

Normally when we haven't implemented an alignment handler for
a load or store instruction the process will be terminated.

The alignment handler uses the DSISR (or a pseudo one) to locate
the right handler. Unfortunately ldbrx and stdbrx overlap lfs and
stfs so we incorrectly think ldbrx is an lfs and stdbrx is an
stfs.

This bug is particularly nasty - instead of terminating the
process we apply an incorrect fixup and continue on.

With more and more overlapping instructions we should stop
creating a pseudo DSISR and index using the instruction directly,
but for now add a special case to catch ldbrx/stdbrx.

Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
arch/powerpc/kernel/align.c