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authorVineet Gupta <vgupta@synopsys.com>2017-01-27 10:45:27 -0800
committerSasha Levin <alexander.levin@verizon.com>2017-03-06 17:31:12 -0500
commit36446d0a124c7b751412122c05fcb1165771e8fa (patch)
treefb49cebb660fd7958ba8d0a02aaac01b9314c0de
parente30295a2f487fb7a347ed6d3d1937118b7a4b923 (diff)
downloadlinux-linaro-stable-36446d0a124c7b751412122c05fcb1165771e8fa.tar.gz
ARC: [arcompact] handle unaligned access delay slot corner case
[ Upstream commit 9aed02feae57bf7a40cb04ea0e3017cb7a998db4 ] After emulating an unaligned access in delay slot of a branch, we pretend as the delay slot never happened - so return back to actual branch target (or next PC if branch was not taken). Curently we did this by handling STATUS32.DE, we also need to clear the BTA.T bit, which is disregarded when returning from original misaligned exception, but could cause weirdness if it took the interrupt return path (in case interrupt was acive too) One ARC700 customer ran into this when enabling unaligned access fixup for kernel mode accesses as well Cc: stable@vger.kernel.org Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
-rw-r--r--arch/arc/kernel/unaligned.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arc/kernel/unaligned.c b/arch/arc/kernel/unaligned.c
index 74db59b6f392..9155e6cbc13d 100644
--- a/arch/arc/kernel/unaligned.c
+++ b/arch/arc/kernel/unaligned.c
@@ -241,8 +241,9 @@ int misaligned_fixup(unsigned long address, struct pt_regs *regs,
if (state.fault)
goto fault;
+ /* clear any remanants of delay slot */
if (delay_mode(regs)) {
- regs->ret = regs->bta;
+ regs->ret = regs->bta ~1U;
regs->status32 &= ~STATUS_DE_MASK;
} else {
regs->ret += state.instr_len;