Implements an x86_64 assembler driver for the Poly1305 authenticator. This
single block variant holds the 130-bit integer in 5 32-bit words, but uses
SSE to do two multiplications/additions in parallel.

When calling updates with small blocks, the overhead for kernel_fpu_begin/
kernel_fpu_end() negates the perfmance gain. We therefore use the
poly1305-generic fallback for small updates.

For large messages, throughput increases by ~5-10% compared to
poly1305-generic:

testing speed of poly1305 (poly1305-generic)
test  0 (   96 byte blocks,   16 bytes per update,   6 updates): 4080026 opers/sec,  391682496 bytes/sec
test  1 (   96 byte blocks,   32 bytes per update,   3 updates): 6221094 opers/sec,  597225024 bytes/sec
test  2 (   96 byte blocks,   96 bytes per update,   1 updates): 9609750 opers/sec,  922536057 bytes/sec
test  3 (  288 byte blocks,   16 bytes per update,  18 updates): 1459379 opers/sec,  420301267 bytes/sec
test  4 (  288 byte blocks,   32 bytes per update,   9 updates): 2115179 opers/sec,  609171609 bytes/sec
test  5 (  288 byte blocks,  288 bytes per update,   1 updates): 3729874 opers/sec, 1074203856 bytes/sec
test  6 ( 1056 byte blocks,   32 bytes per update,  33 updates):  593000 opers/sec,  626208000 bytes/sec
test  7 ( 1056 byte blocks, 1056 bytes per update,   1 updates): 1081536 opers/sec, 1142102332 bytes/sec
test  8 ( 2080 byte blocks,   32 bytes per update,  65 updates):  302077 opers/sec,  628320576 bytes/sec
test  9 ( 2080 byte blocks, 2080 bytes per update,   1 updates):  554384 opers/sec, 1153120176 bytes/sec
test 10 ( 4128 byte blocks, 4128 bytes per update,   1 updates):  278715 opers/sec, 1150536345 bytes/sec
test 11 ( 8224 byte blocks, 8224 bytes per update,   1 updates):  140202 opers/sec, 1153022070 bytes/sec

testing speed of poly1305 (poly1305-simd)
test  0 (   96 byte blocks,   16 bytes per update,   6 updates): 3790063 opers/sec,  363846076 bytes/sec
test  1 (   96 byte blocks,   32 bytes per update,   3 updates): 5913378 opers/sec,  567684355 bytes/sec
test  2 (   96 byte blocks,   96 bytes per update,   1 updates): 9352574 opers/sec,  897847104 bytes/sec
test  3 (  288 byte blocks,   16 bytes per update,  18 updates): 1362145 opers/sec,  392297990 bytes/sec
test  4 (  288 byte blocks,   32 bytes per update,   9 updates): 2007075 opers/sec,  578037628 bytes/sec
test  5 (  288 byte blocks,  288 bytes per update,   1 updates): 3709811 opers/sec, 1068425798 bytes/sec
test  6 ( 1056 byte blocks,   32 bytes per update,  33 updates):  566272 opers/sec,  597984182 bytes/sec
test  7 ( 1056 byte blocks, 1056 bytes per update,   1 updates): 1111657 opers/sec, 1173910108 bytes/sec
test  8 ( 2080 byte blocks,   32 bytes per update,  65 updates):  288857 opers/sec,  600823808 bytes/sec
test  9 ( 2080 byte blocks, 2080 bytes per update,   1 updates):  590746 opers/sec, 1228751888 bytes/sec
test 10 ( 4128 byte blocks, 4128 bytes per update,   1 updates):  301825 opers/sec, 1245936902 bytes/sec
test 11 ( 8224 byte blocks, 8224 bytes per update,   1 updates):  153075 opers/sec, 1258896201 bytes/sec

Benchmark results from a Core i5-4670T.

Signed-off-by: Martin Willi <martin@strongswan.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>