Patch "MIPS: R2-on-R6 MULTU/MADDU/MSUBU emulation bugfix" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

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

    MIPS: R2-on-R6 MULTU/MADDU/MSUBU emulation bugfix

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-r2-on-r6-multu-maddu-msubu-emulation-bugfix.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@vger.kernel.org> know about it.


>From d65e5677ad5b3a49c43f60ec07644dc1f87bbd2e Mon Sep 17 00:00:00 2001
From: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Date: Thu, 25 Aug 2016 10:37:38 -0700
Subject: MIPS: R2-on-R6 MULTU/MADDU/MSUBU emulation bugfix

From: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>

commit d65e5677ad5b3a49c43f60ec07644dc1f87bbd2e upstream.

MIPS instructions MULTU, MADDU and MSUBU emulation requires registers HI/LO
to be converted to signed 32bits before 64bit sign extension on MIPS64.

Bug was found on running MIPS32 R2 test application on MIPS64 R6 kernel.

Fixes: b0a668fb2038 ("MIPS: kernel: mips-r2-to-r6-emul: Add R2 emulator for MIPS R6")
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Reported-by: Nikola.Veljkovic@imgtec.com
Cc: paul.burton@imgtec.com
Cc: yamada.masahiro@socionext.com
Cc: akpm@linux-foundation.org
Cc: andrea.gelmini@gelma.net
Cc: macro@imgtec.com
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14043/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/mips/kernel/mips-r2-to-r6-emul.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--- a/arch/mips/kernel/mips-r2-to-r6-emul.c
+++ b/arch/mips/kernel/mips-r2-to-r6-emul.c
@@ -434,8 +434,8 @@ static int multu_func(struct pt_regs *re
 	rs = regs->regs[MIPSInst_RS(ir)];
 	res = (u64)rt * (u64)rs;
 	rt = res;
-	regs->lo = (s64)rt;
-	regs->hi = (s64)(res >> 32);
+	regs->lo = (s64)(s32)rt;
+	regs->hi = (s64)(s32)(res >> 32);
 
 	MIPS_R2_STATS(muls);
 
@@ -671,9 +671,9 @@ static int maddu_func(struct pt_regs *re
 	res += ((((s64)rt) << 32) | (u32)rs);
 
 	rt = res;
-	regs->lo = (s64)rt;
+	regs->lo = (s64)(s32)rt;
 	rs = res >> 32;
-	regs->hi = (s64)rs;
+	regs->hi = (s64)(s32)rs;
 
 	MIPS_R2_STATS(dsps);
 
@@ -729,9 +729,9 @@ static int msubu_func(struct pt_regs *re
 	res = ((((s64)rt) << 32) | (u32)rs) - res;
 
 	rt = res;
-	regs->lo = (s64)rt;
+	regs->lo = (s64)(s32)rt;
 	rs = res >> 32;
-	regs->hi = (s64)rs;
+	regs->hi = (s64)(s32)rs;
 
 	MIPS_R2_STATS(dsps);
 


Patches currently in stable-queue which might be from Leonid.Yegoshin@imgtec.com are

queue-4.4/mips-r2-on-r6-multu-maddu-msubu-emulation-bugfix.patch