[PATCH] powerpc/32: fix csum_partial_copy_generic()

Christophe Leroy
2016-08-01T12:57:12Z

commit 7aef4136566b0 ("powerpc32: rewrite csum_partial_copy_generic()
based on copy_tofrom_user()") introduced a bug when destination
address is odd and initial csum is not null

In that (rare) case the initial csum value has to be rotated one byte
as well as the resulting value is

Fixes: 7aef4136566b0 ("powerpc32: rewrite csum_partial_copy_generic()
based on copy_tofrom_user()")
Cc: stable@vger.kernel.org

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/lib/checksum_32.S | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/lib/checksum_32.S b/arch/powerpc/lib/checksum_32.S
index d90870a..ad0870a 100644
--- a/arch/powerpc/lib/checksum_32.S
+++ b/arch/powerpc/lib/checksum_32.S
@@ -127,7 +127,8 @@ _GLOBAL(csum_partial_copy_generic)
stw r7,12(r1)
stw r8,8(r1)

- andi. r0,r4,1 /* is destination address even ? */
+ rlwinm r0,r4,3,0x8 /* is destination address even ? */
+ rlwnm r6,r6,r0,0,31 /* swap bytes for odd destination */
cmplwi cr7,r0,0
addic r12,r6,0
addi r6,r4,-4
--
2.1.0