From: Mike Ditto <mditto@consentry.com>
Date: Fri, 17 Oct 2008 09:27:51 +0000 (+0000)
Subject: powerpc: Fix boot wrapper memcmp() called with zero length argument
X-Git-Tag: v2.6.28-rc1~58^2~22
X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=59fd6b8cc0975b88e35f6ca2318b8cee77d3a508;p=linux-2.6-omap-h63xx.git

powerpc: Fix boot wrapper memcmp() called with zero length argument

I noticed, when trying to use, e.g.,
node = find_node_by_prop_value(prev, "booleanprop", "", 0))
to search for all nodes with a certain boolean property, that memcmp()
returns garbage when comparing zero bytes.  It should return zero.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---

diff --git a/arch/powerpc/boot/string.S b/arch/powerpc/boot/string.S
index 643e4cb2f11..acc9428f278 100644
--- a/arch/powerpc/boot/string.S
+++ b/arch/powerpc/boot/string.S
@@ -235,7 +235,7 @@ memchr:
 	.globl	memcmp
 memcmp:
 	cmpwi	0,r5,0
-	blelr
+	ble	2f
 	mtctr	r5
 	addi	r6,r3,-1
 	addi	r4,r4,-1
@@ -244,6 +244,8 @@ memcmp:
 	subf.	r3,r0,r3
 	bdnzt	2,1b
 	blr
+2:	li	r3,0
+	blr
 
 
 /*