Re: [PATCH] powerpc: fix csum_ipv6_magic() on little endian platforms

[Christophe LEROY]

Hi Michael,

Le 10/09/2018 Ã 16:28, Xin Long a ÃcritÂ:
> On Mon, Sep 10, 2018 at 2:09 PM Christophe Leroy
> <christophe.leroy@xxxxxx> wrote:
> > 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@xxxxxxxxxx>
> > Reported-by: Xin Long <lucien.xin@xxxxxxxxx>
> > Cc: <stable@xxxxxxxxxxxxxxx> # 4.18+
> > Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
> > ---
> >   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
> > --
> > 2.13.3
> Tested-by: Xin Long <lucien.xin@xxxxxxxxx>

Could you take this fix for 4.19 ?

Unless someone takes it through the netdev tree ?

Thanks
Christophe