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authorRalf Baechle <ralf@linux-mips.org>2005-09-20 06:56:26 -0400
committerRalf Baechle <ralf@linux-mips.org>2005-10-29 14:32:25 -0400
commite97288386a316e3960b758a60ae7cd17b3ee10e7 (patch)
tree5a40713cc8ceec43a9ed0d2f02373a1e5a2d648f /include/asm-mips/checksum.h
parent2cce8263228ac8926d675cfa19e50ca0af9e05e4 (diff)
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/checksum.h')
-rw-r--r--include/asm-mips/checksum.h2
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,
150 " daddu %0, %4 \n" 150 " daddu %0, %4 \n"
151 " dsll32 $1, %0, 0 \n" 151 " dsll32 $1, %0, 0 \n"
152 " daddu %0, $1 \n" 152 " daddu %0, $1 \n"
153 " dsrl32 %0, %0, 0 \n" 153 " dsra32 %0, %0, 0 \n"
154#endif 154#endif
155 " .set pop" 155 " .set pop"
156 : "=r" (sum) 156 : "=r" (sum)