[3.16.y-ckt stable] Patch "MIPS: CPS: Stop dangling delay slot from has_mt." has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    MIPS: CPS: Stop dangling delay slot from has_mt.

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt19.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From ecab244e2724ec7bed31a597d71e1daa6590f53e Mon Sep 17 00:00:00 2001
From: Paul Burton <paul.burton at imgtec.com>
Date: Wed, 5 Aug 2015 15:42:36 -0700
Subject: MIPS: CPS: Stop dangling delay slot from has_mt.

commit 1e5fb282f8eda889776ee83f9214d5df9edaa26d upstream.

The has_mt macro ended with a branch, leaving its callers with a delay
slot that would be executed if Config3.MT is not set. However it would
not be executed if Config3 (or earlier Config registers) don't exist
which makes it somewhat inconsistent at best. Fill the delay slot in the
macro & fix the mips_cps_boot_vpes caller appropriately.

Signed-off-by: Paul Burton <paul.burton at imgtec.com>
Cc: Markos Chandras <markos.chandras at imgtec.com>
Cc: James Hogan <james.hogan at imgtec.com>
Cc: linux-mips at linux-mips.org
Cc: linux-kernel at vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10865/
Signed-off-by: Ralf Baechle <ralf at linux-mips.org>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/mips/kernel/cps-vec.S | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/mips/kernel/cps-vec.S b/arch/mips/kernel/cps-vec.S
index 3b3fb8924628..5652af5786ef 100644
--- a/arch/mips/kernel/cps-vec.S
+++ b/arch/mips/kernel/cps-vec.S
@@ -39,6 +39,7 @@
 	 mfc0	\dest, CP0_CONFIG, 3
 	andi	\dest, \dest, MIPS_CONF3_MT
 	beqz	\dest, \nomt
+	 nop
 	.endm

 .section .text.cps-vec
@@ -226,7 +227,6 @@ LEAF(mips_cps_core_init)
 #ifdef CONFIG_MIPS_MT
 	/* Check that the core implements the MT ASE */
 	has_mt	t0, 3f
-	 nop

 	.set	push
 	.set	mt
@@ -309,8 +309,8 @@ LEAF(mips_cps_boot_vpes)
 	addu	t0, t0, t1

 	/* Calculate this VPEs ID. If the core doesn't support MT use 0 */
+	li	t9, 0
 	has_mt	t6, 1f
-	 li	t9, 0

 	/* Find the number of VPEs present in the core */
 	mfc0	t1, CP0_MVPCONF0