powerpc: fix csum_ipv6_magic() on little endian platforms

On little endian platforms, csum_ipv6_magic() keeps len and proto in
CPU byte order. This generates a bad results leading to ICMPv6 packets
from other hosts being dropped by powerpc64le platforms.

In order to fix this, len and proto should be converted to network
byte order ie bigendian byte order. However checksumming 0x12345678
and 0x56341278 provide the exact same result so it is enough to
rotate the sum of len and proto by 1 byte.

PPC32 only support bigendian so the fix is needed for PPC64 only

Fixes: e9c4943a10 ("powerpc: Implement csum_ipv6_magic in assembly")
Reported-by: Jianlin Shi <jishi@redhat.com>
Reported-by: Xin Long <lucien.xin@gmail.com>
Cc: <stable@vger.kernel.org> # 4.18+
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Tested-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Christophe Leroy 2018-09-10 06:09:04 +00:00 committed by Michael Ellerman
parent 7233b8cab3
commit 85682a7e3b

View file

@ -443,6 +443,9 @@ _GLOBAL(csum_ipv6_magic)
addc r0, r8, r9
ld r10, 0(r4)
ld r11, 8(r4)
#ifdef CONFIG_CPU_LITTLE_ENDIAN
rotldi r5, r5, 8
#endif
adde r0, r0, r10
add r5, r5, r7
adde r0, r0, r11