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[MIPS] Fix wrong checksum calculation on 64-bit MIPS

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The commit 8e3d8433d8 ([NET]: MIPS
checksum annotations and cleanups) broke 64-bit MIPS.

The problem is the commit replaces some unsigned long with __be32.  On
64bit MIPS, a __be32 (i.e. unsigned int) value is represented as a
sign-extented 32-bit value in a 64-bit argument register.  So the
address 192.168.0.1 (0xc0a80001) is passed as 0xffffffffc0a80001 to
csum_tcpudp_nofold() but the asm code in the function expects
0x00000000c0a80001, therefore it returns a wrong checksum.  Explicit
cast to unsigned long is needed to drop high 32bit.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Atsushi Nemoto 2007-01-24 15:43:34 +09:00 committed by Ralf Baechle
parent 9cfdf6f15a
commit 66218da212
1 changed files with 2 additions and 1 deletions
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3
include/asm-mips/checksum.h
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@ -159,7 +159,8 @@ static inline __wsum csum_tcpudp_nofold(__be32 saddr,
#endif
" .set pop"
: "=r" (sum)
: "0" (daddr), "r"(saddr),
: "0" ((__force unsigned long)daddr),
"r" ((__force unsigned long)saddr),
#ifdef __MIPSEL__
"r" ((proto + len) << 8),
#else