[3.8.y.z extended stable] Patch "ARM: 7670/1: fix the memset fix" has been added to staging queue

[Kamal Mostafa]

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

    ARM: 7670/1: fix the memset fix

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.20.

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

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 7022c18e0431d9672b13dbb8d7228e9e142e8ed8 Mon Sep 17 00:00:00 2001
From: Nicolas Pitre <nicolas.pitre at linaro.org>
Date: Tue, 12 Mar 2013 13:00:42 +0100
Subject: ARM: 7670/1: fix the memset fix

commit 418df63adac56841ef6b0f1fcf435bc64d4ed177 upstream.

Commit 455bd4c430b0 ("ARM: 7668/1: fix memset-related crashes caused by
recent GCC (4.7.2) optimizations") attempted to fix a compliance issue
with the memset return value.  However the memset itself became broken
by that patch for misaligned pointers.

This fixes the above by branching over the entry code from the
misaligned fixup code to avoid reloading the original pointer.

Also, because the function entry alignment is wrong in the Thumb mode
compilation, that fixup code is moved to the end.

While at it, the entry instructions are slightly reworked to help dual
issue pipelines.

Signed-off-by: Nicolas Pitre <nico at linaro.org>
Tested-by: Alexander Holler <holler at ahsoftware.de>
Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
Cc: Florian Fainelli <f.fainelli at gmail.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 arch/arm/lib/memset.S | 33 +++++++++++++--------------------
 1 file changed, 13 insertions(+), 20 deletions(-)

diff --git a/arch/arm/lib/memset.S b/arch/arm/lib/memset.S
index d912e73..94b0650 100644
--- a/arch/arm/lib/memset.S
+++ b/arch/arm/lib/memset.S
@@ -14,31 +14,15 @@

 	.text
 	.align	5
-	.word	0
-
-1:	subs	r2, r2, #4		@ 1 do we have enough
-	blt	5f			@ 1 bytes to align with?
-	cmp	r3, #2			@ 1
-	strltb	r1, [ip], #1		@ 1
-	strleb	r1, [ip], #1		@ 1
-	strb	r1, [ip], #1		@ 1
-	add	r2, r2, r3		@ 1 (r2 = r2 - (4 - r3))
-/*
- * The pointer is now aligned and the length is adjusted.  Try doing the
- * memset again.
- */

 ENTRY(memset)
-/*
- * Preserve the contents of r0 for the return value.
- */
-	mov	ip, r0
-	ands	r3, ip, #3		@ 1 unaligned?
-	bne	1b			@ 1
+	ands	r3, r0, #3		@ 1 unaligned?
+	mov	ip, r0			@ preserve r0 as return value
+	bne	6f			@ 1
 /*
  * we know that the pointer in ip is aligned to a word boundary.
  */
-	orr	r1, r1, r1, lsl #8
+1:	orr	r1, r1, r1, lsl #8
 	orr	r1, r1, r1, lsl #16
 	mov	r3, r1
 	cmp	r2, #16
@@ -127,4 +111,13 @@ ENTRY(memset)
 	tst	r2, #1
 	strneb	r1, [ip], #1
 	mov	pc, lr
+
+6:	subs	r2, r2, #4		@ 1 do we have enough
+	blt	5b			@ 1 bytes to align with?
+	cmp	r3, #2			@ 1
+	strltb	r1, [ip], #1		@ 1
+	strleb	r1, [ip], #1		@ 1
+	strb	r1, [ip], #1		@ 1
+	add	r2, r2, r3		@ 1 (r2 = r2 - (4 - r3))
+	b	1b
 ENDPROC(memset)
--
1.8.3.2