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authorVineet Gupta <vgupta@synopsys.com>2017-01-27 10:45:27 -0800
committerVineet Gupta <vgupta@synopsys.com>2017-01-27 10:54:20 -0800
commit9aed02feae57bf7a40cb04ea0e3017cb7a998db4 (patch)
treea3abfdd6f3bf53f2395ea8c27ed5f1a4f1988c40
parent78f824d4312a8944f5340c6b161bba3bf2c81096 (diff)
downloadlinux-sh-9aed02feae57bf7a40cb04ea0e3017cb7a998db4.tar.gz
ARC: [arcompact] handle unaligned access delay slot corner case
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>
-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 abd961f3e763..91ebe382147f 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;