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| author | Ralf Baechle <ralf@linux-mips.org> | 2005-09-20 10:56:26 +0000 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2005-10-29 19:32:25 +0100 |
| commit | e97288386a316e3960b758a60ae7cd17b3ee10e7 (patch) | |
| tree | 5a40713cc8ceec43a9ed0d2f02373a1e5a2d648f /include/asm-mips | |
| parent | 2cce8263228ac8926d675cfa19e50ca0af9e05e4 (diff) | |
| download | linux-e97288386a316e3960b758a60ae7cd17b3ee10e7.tar.gz linux-e97288386a316e3960b758a60ae7cd17b3ee10e7.tar.bz2 linux-e97288386a316e3960b758a60ae7cd17b3ee10e7.zip | |
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>
Diffstat (limited to 'include/asm-mips')
| -rw-r--r-- | include/asm-mips/checksum.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/asm-mips/checksum.h b/include/asm-mips/checksum.h index 2ff53db8c023..b09f8971e95d 100644 --- a/include/asm-mips/checksum.h +++ b/include/asm-mips/checksum.h @@ -150,7 +150,7 @@ static inline unsigned int csum_tcpudp_nofold(unsigned long saddr, " daddu %0, %4 \n" " dsll32 $1, %0, 0 \n" " daddu %0, $1 \n" - " dsrl32 %0, %0, 0 \n" + " dsra32 %0, %0, 0 \n" #endif " .set pop" : "=r" (sum) |