| commit | b492f7e4e07a28e706db26cf4943bb0911435426 | |
| author | Paul Mackerras <paulus@ozlabs.org> | |
| Thu, 3 Nov 2016 05:10:55 +0000 (3 16:10 +1100) | ||
| committer | Michael Ellerman <mpe@ellerman.id.au> | |
| Wed, 25 Jan 2017 02:34:18 +0000 (25 13:34 +1100) | ||
| tree | 2e5ce673c7553a9faccc17100785235cc8df9d0d | treesnapshot (tar.gz zip) |
| parent | 14a41d6b7572026cf8fc88ee72e81b6b40db2ec0 | commitdiff |
powerpc/64: Fix checksum folding in csum_tcpudp_nofold and ip_fast_csum_nofold
These functions compute an IP checksum by computing a 64-bit sum and
folding it to 32 bits (the "nofold" in their names refers to folding
down to 16 bits). However, doing (u32) (s + (s >> 32)) is not
sufficient to fold a 64-bit sum to 32 bits correctly. The addition
can produce a carry out from bit 31, which needs to be added in to
the sum to produce the correct result.
To fix this, we copy the from64to32() function from lib/checksum.c
and use that.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
These functions compute an IP checksum by computing a 64-bit sum and
folding it to 32 bits (the "nofold" in their names refers to folding
down to 16 bits). However, doing (u32) (s + (s >> 32)) is not
sufficient to fold a 64-bit sum to 32 bits correctly. The addition
can produce a carry out from bit 31, which needs to be added in to
the sum to produce the correct result.
To fix this, we copy the from64to32() function from lib/checksum.c
and use that.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| arch/powerpc/include/asm/checksum.h | diffblobblamehistory |