This is a note to let you know that I've just added the patch titled
MIPS: Fix unaligned PC interpretation in `compute_return_epc'
to the 4.4-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:
mips-fix-unaligned-pc-interpretation-in-compute_return_epc.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 11a3799dbeb620bf0400b1fda5cc2c6bea55f20a Mon Sep 17 00:00:00 2001
From: "Maciej W. Rozycki" <macro@xxxxxxxxxx>
Date: Fri, 16 Jun 2017 00:07:34 +0100
Subject: MIPS: Fix unaligned PC interpretation in `compute_return_epc'
From: Maciej W. Rozycki <macro@xxxxxxxxxx>
commit 11a3799dbeb620bf0400b1fda5cc2c6bea55f20a upstream.
Fix a regression introduced with commit fb6883e5809c ("MIPS: microMIPS:
Support handling of delay slots.") and defer to `__compute_return_epc'
if the ISA bit is set in EPC with non-MIPS16, non-microMIPS hardware,
which will then arrange for a SIGBUS due to an unaligned instruction
reference. Returning EPC here is never correct as the API defines this
function's result to be either a negative error code on failure or one
of 0 and BRANCH_LIKELY_TAKEN on success.
Fixes: fb6883e5809c ("MIPS: microMIPS: Support handling of delay slots.")
Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxxxx>
Cc: James Hogan <james.hogan@xxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Patchwork: https://patchwork.linux-mips.org/patch/16395/
Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/mips/include/asm/branch.h | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
--- a/arch/mips/include/asm/branch.h
+++ b/arch/mips/include/asm/branch.h
@@ -74,10 +74,7 @@ static inline int compute_return_epc(str
return __microMIPS_compute_return_epc(regs);
if (cpu_has_mips16)
return __MIPS16e_compute_return_epc(regs);
- return regs->cp0_epc;
- }
-
- if (!delay_slot(regs)) {
+ } else if (!delay_slot(regs)) {
regs->cp0_epc += 4;
return 0;
}
Patches currently in stable-queue which might be from macro@xxxxxxxxxx are
queue-4.4/mips-send-sigill-for-bposge32-in-__compute_return_epc_for_insn.patch
queue-4.4/mips-actually-decode-jalx-in-__compute_return_epc_for_insn.patch
queue-4.4/mips-fix-a-typo-s-preset-present-in-r2-to-r6-emulation-error-message.patch
queue-4.4/mips-fix-unaligned-pc-interpretation-in-compute_return_epc.patch
queue-4.4/mips-rename-sigill_r6-to-sigill_r2r6-in-__compute_return_epc_for_insn.patch
queue-4.4/mips-send-sigill-for-linked-branches-in-__compute_return_epc_for_insn.patch
queue-4.4/mips-math-emu-prevent-wrong-isa-mode-instruction-emulation.patch