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/arch/x86/include/asm/serpent.h b/arch/x86/include/asm/serpent.h
new file mode 100644
index 0000000..b7fd3b5
--- /dev/null
+++ b/arch/x86/include/asm/serpent.h
@@ -0,0 +1,32 @@
+#ifndef ASM_X86_SERPENT_H
+#define ASM_X86_SERPENT_H
+
+#include <linux/crypto.h>
+#include <crypto/serpent.h>
+
+#define SERPENT_PARALLEL_BLOCKS 8
+
+asmlinkage void __serpent_enc_blk_8way(struct serpent_ctx *ctx, u8 *dst,
+				       const u8 *src, bool xor);
+asmlinkage void serpent_dec_blk_8way(struct serpent_ctx *ctx, u8 *dst,
+				     const u8 *src);
+
+static inline void serpent_enc_blk_xway(struct serpent_ctx *ctx, u8 *dst,
+				   const u8 *src)
+{
+	__serpent_enc_blk_8way(ctx, dst, src, false);
+}
+
+static inline void serpent_enc_blk_xway_xor(struct serpent_ctx *ctx, u8 *dst,
+				       const u8 *src)
+{
+	__serpent_enc_blk_8way(ctx, dst, src, true);
+}
+
+static inline void serpent_dec_blk_xway(struct serpent_ctx *ctx, u8 *dst,
+				   const u8 *src)
+{
+	serpent_dec_blk_8way(ctx, dst, src);
+}
+
+#endif