shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-04 02:02:28 +09:00
Code Issues Packages Projects Releases Wiki Activity

powerpc: Handle unaligned ldbrx/stdbrx

Browse Source 
commit 230aef7a6a 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>
This commit is contained in:
Anton Blanchard
2013-08-07 02:01:19 +10:00
committed by Greg Kroah-Hartman
parent 139653e11c
commit d8ba750f9a
1 changed files with 10 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
arch/powerpc/kernel/align.c
View File

@@ -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) {