tree 5a40713cc8ceec43a9ed0d2f02373a1e5a2d648f
parent 2cce8263228ac8926d675cfa19e50ca0af9e05e4
author Ralf Baechle <ralf@linux-mips.org> 1127213786 +0000
committer Ralf Baechle <ralf@linux-mips.org> 1130610745 +0100

The type of sum in csum_tcpudp_nofold is "unsigned int", so when we assign
to it in an asm() block, and we're running on a system with 64-bit
registers, it is vitally important that we sign extend it correctly before
returning to C.  Otherwise the stray high bits will be preserved into
csum_fold, and on the SB-1 processor, 32-bit arithmetic on a non
sign-extended register will yield surprising results.
    
This caused incorrect checksums in some UDP packets for NFS root.  The
problem was mild when using a 10.0.1.x IP address, but severe when
using 192.168.1.x.
    
Signed-off-by: Daniel Jacobowitz <dan@codesourcery.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>