powerpc: Handle unaligned ldbrx/stdbrx
authorAnton Blanchard <anton@samba.org>
Tue, 6 Aug 2013 16:01:19 +0000 (02:01 +1000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 27 Sep 2013 00:21:35 +0000 (17:21 -0700)
commitde68bdcc45f558cd4e47a1f376e1bf65377ccb35
tree6af0222dc5ea02a046d74e35df26af9db2206620
parentae797590117c1631e61af6d9c580c3ca2c397716
powerpc: Handle unaligned ldbrx/stdbrx

commit 230aef7a6a23b6166bd4003bfff5af23c9bd381f upstream.

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>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/powerpc/kernel/align.c