This is a note to let you know that I've just added the patch titled
powerpc: Handle unaligned ldbrx/stdbrx
to the 3.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
powerpc-handle-unaligned-ldbrx-stdbrx.patch
and it can be found in the queue-3.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 230aef7a6a23b6166bd4003bfff5af23c9bd381f Mon Sep 17 00:00:00 2001
From: Anton Blanchard <anton@xxxxxxxxx>
Date: Wed, 7 Aug 2013 02:01:19 +1000
Subject: powerpc: Handle unaligned ldbrx/stdbrx
From: Anton Blanchard <anton@xxxxxxxxx>
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@xxxxxxxxx>
Signed-off-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/kernel/align.c | 10 ++++++++++
1 file changed, 10 insertions(+)
--- a/arch/powerpc/kernel/align.c
+++ b/arch/powerpc/kernel/align.c
@@ -764,6 +764,16 @@ int fix_alignment(struct pt_regs *regs)
nb = aligninfo[instr].len;
flags = aligninfo[instr].flags;
+ /* ldbrx/stdbrx overlap lfs/stfs in the DSISR unfortunately */
+ if (IS_XFORM(instruction) && ((instruction >> 1) & 0x3ff) == 532) {
+ nb = 8;
+ flags = LD+SW;
+ } else if (IS_XFORM(instruction) &&
+ ((instruction >> 1) & 0x3ff) == 660) {
+ nb = 8;
+ flags = ST+SW;
+ }
+
/* Byteswap little endian loads and stores */
swiz = 0;
if (regs->msr & MSR_LE) {
Patches currently in stable-queue which might be from anton@xxxxxxxxx are
queue-3.11/powerpc-handle-unaligned-ldbrx-stdbrx.patch
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