crypto: serpent - add 8-way parallel x86_64/SSE2 assembler implementation

Patch adds x86_64/SSE2 assembler implementation of serpent cipher. Assembler
functions crypt data in eigth block chunks (two 4 block chunk SSE2 operations
in parallel to improve performance on out-of-order CPUs). Glue code is based
on one from AES-NI implementation, so requests from irq context are redirected
to cryptd.

v2:
 - add missing include of linux/module.h
   (appearently crypto.h used to include module.h, which changed for 3.2 by
    commit 7c926402a7e8c9b279968fd94efec8700ba3859e)

Patch has been tested with tcrypt and automated filesystem tests.

Tcrypt benchmarks results (serpent-sse2/serpent_generic speed ratios):

AMD Phenom II 1055T (fam:16, model:10):

size    ecb-enc ecb-dec cbc-enc cbc-dec ctr-enc ctr-dec
16B     1.03x   1.01x   1.03x   1.05x   1.00x   0.99x
64B     1.00x   1.01x   1.02x   1.04x   1.02x   1.01x
256B    2.34x   2.41x   0.99x   2.43x   2.39x   2.40x
1024B   2.51x   2.57x   1.00x   2.59x   2.56x   2.56x
8192B   2.50x   2.54x   1.00x   2.55x   2.57x   2.57x

Intel Celeron T1600 (fam:6, model:15, step:13):

size    ecb-enc ecb-dec cbc-enc cbc-dec ctr-enc ctr-dec
16B     0.97x   0.97x   1.01x   1.01x   1.01x   1.02x
64B     1.00x   1.00x   1.00x   1.02x   1.01x   1.01x
256B    3.41x   3.35x   1.00x   3.39x   3.42x   3.44x
1024B   3.75x   3.72x   0.99x   3.74x   3.75x   3.75x
8192B   3.70x   3.68x   0.99x   3.68x   3.69x   3.69x

Full output:
 http://koti.mbnet.fi/axh/kernel/crypto/phenom-ii-1055t/serpent-generic.txt
 http://koti.mbnet.fi/axh/kernel/crypto/phenom-ii-1055t/serpent-sse2.txt
 http://koti.mbnet.fi/axh/kernel/crypto/celeron-t1600/serpent-generic.txt
 http://koti.mbnet.fi/axh/kernel/crypto/celeron-t1600/serpent-sse2.txt

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/Kconfig b/crypto/Kconfig
index 733208f..2df61e4 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -766,6 +766,23 @@
 	  See also:
 	  <http://www.cl.cam.ac.uk/~rja14/serpent.html>
 
+config CRYPTO_SERPENT_SSE2_X86_64
+	tristate "Serpent cipher algorithm (x86_64/SSE2)"
+	depends on X86 && 64BIT
+	select CRYPTO_ALGAPI
+	select CRYPTO_SERPENT
+	help
+	  Serpent cipher algorithm, by Anderson, Biham & Knudsen.
+
+	  Keys are allowed to be from 0 to 256 bits in length, in steps
+	  of 8 bits.
+
+	  This module provides Serpent cipher algorithm that processes eigth
+	  blocks parallel using SSE2 instruction set.
+
+	  See also:
+	  <http://www.cl.cam.ac.uk/~rja14/serpent.html>
+
 config CRYPTO_TEA
 	tristate "TEA, XTEA and XETA cipher algorithms"
 	select CRYPTO_ALGAPI