Patch "MIPS: Fix erroneous JR emulation for MIPS R6" has been added to the 4.1-stable tree

Patch "MIPS: Fix erroneous JR emulation for MIPS R6" has been added to the 4.1-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    MIPS: Fix erroneous JR emulation for MIPS R6

to the 4.1-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-erroneous-jr-emulation-for-mips-r6.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 143fefc8f315cd10e046e6860913c421c3385cb1 Mon Sep 17 00:00:00 2001
From: Markos Chandras <markos.chandras@imgtec.com>
Date: Wed, 24 Jun 2015 09:52:01 +0100
Subject: MIPS: Fix erroneous JR emulation for MIPS R6

From: Markos Chandras <markos.chandras@imgtec.com>

commit 143fefc8f315cd10e046e6860913c421c3385cb1 upstream.

Commit 5f9f41c474befb4ebbc40b27f65bb7d649241581 ("MIPS: kernel: Prepare
the JR instruction for emulation on MIPS R6") added support for
emulating the JR instruction on MIPS R6 cores but that introduced a bug
which could be triggered when hitting a JALR opcode because the code used
the wrong field in the 'r_format' struct to determine the instruction
opcode. This lead to crashes because an emulated JALR instruction was
treated as a JR one when the R6 emulator was turned off.

Fixes: 5f9f41c474be ("MIPS: kernel: Prepare the JR instruction for emulation on MIPS R6")
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10583/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/mips/math-emu/cp1emu.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/mips/math-emu/cp1emu.c
+++ b/arch/mips/math-emu/cp1emu.c
@@ -451,7 +451,7 @@ static int isBranchInstr(struct pt_regs
 			/* Fall through */
 		case jr_op:
 			/* For R6, JR already emulated in jalr_op */
-			if (NO_R6EMU && insn.r_format.opcode == jr_op)
+			if (NO_R6EMU && insn.r_format.func == jr_op)
 				break;
 			*contpc = regs->regs[insn.r_format.rs];
 			return 1;


Patches currently in stable-queue which might be from markos.chandras@imgtec.com are

queue-4.1/mips-kernel-cps-vec-replace-mips32r2-isa-level-with-mips64r2.patch
queue-4.1/mips-kernel-cps-vec-use-ta0-ta3-pseudo-registers-for-64-bit.patch
queue-4.1/revert-mips-kconfig-disable-smp-cps-for-64-bit.patch
queue-4.1/mips-require-o32-fp64-support-for-mips64-with-o32-compat.patch
queue-4.1/mips-fpu.h-allow-64-bit-fpu-on-a-64-bit-mips-r6-cpu.patch
queue-4.1/mips-kernel-cps-vec-replace-la-macro-with-ptr_la.patch
queue-4.1/mips-c-r4k-fix-cache-flushing-for-mt-cores.patch
queue-4.1/mips-kernel-smp-cps-fix-64-bit-compatibility-errors-due-to-pointer-casting.patch
queue-4.1/mips-kernel-cps-vec-replace-kseg0-with-ckseg0.patch
queue-4.1/mips-fix-erroneous-jr-emulation-for-mips-r6.patch
queue-4.1/mips-cps-vec-use-macros-for-various-arithmetics-and-memory-operations.patch