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: e9c4943a107b ("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 --- arch/powerpc/lib/checksum_64.S | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/arch/powerpc/lib/checksum_64.S b/arch/powerpc/lib/checksum_64.S index 886ed94b9c13..2a68c43e13f5 100644 --- a/arch/powerpc/lib/checksum_64.S +++ b/arch/powerpc/lib/checksum_64.S @@ -443,6 +443,9 @@ _GLOBAL(csum_ipv6_magic) addc r0, r8, r9 ld r10, 0(r4) ld r11, 8(r4) +#ifndef CONFIG_CPU_BIG_ENDIAN + rotldi r5, r5, 8 +#endif adde r0, r0, r10 add r5, r5, r7 adde r0, r0, r11