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 643e4cb2f11da67f3c55f237ff68fbda5b07687f..acc9428f27897d80db4cd65430fedf1069adbe6c 100644 (file)
--- 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
 
 
 /*