From 875a8e03ec3a1ad083a6b308ce993710c5c54f0c Mon Sep 17 00:00:00 2001 From: Jeff Mahoney Date: Wed, 17 Mar 2010 10:55:51 +0000 Subject: [PATCH] powerpc: Fix handling of strncmp with zero len commit 637a99022fb119b90fb281715d13172f0394fc12 upstream. Commit 0119536c, which added the assembly version of strncmp to powerpc, mentions that it adds two instructions to the version from boot/string.S to allow it to handle len=0. Unfortunately, it doesn't always return 0 when that is the case. The length is passed in r5, but the return value is passed back in r3. In certain cases, this will happen to work. Otherwise it will pass back the address of the first string as the return value. This patch lifts the len <= 0 handling code from memcpy to handle that case. Reported by: Christian_Sellars@symantec.com Signed-off-by: Jeff Mahoney Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/lib/string.S | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/lib/string.S b/arch/powerpc/lib/string.S index 64e2e499e32a..3ac0cd3a5373 100644 --- a/arch/powerpc/lib/string.S +++ b/arch/powerpc/lib/string.S @@ -71,7 +71,7 @@ _GLOBAL(strcmp) _GLOBAL(strncmp) PPC_LCMPI r5,0 - beqlr + ble- 2f mtctr r5 addi r5,r3,-1 addi r4,r4,-1 @@ -82,6 +82,8 @@ _GLOBAL(strncmp) beqlr 1 bdnzt eq,1b blr +2: li r3,0 + blr _GLOBAL(strlen) addi r4,r3,-1 -- 2.39.5