crypto: serpent - add AVX2/x86_64 assembler implementation of serpent cipher

Patch adds AVX2/x86-64 implementation of Serpent cipher, requiring 16 parallel
blocks for input (256 bytes). Implementation is based on the AVX implementation
and extends to use the 256-bit wide YMM registers. Since serpent does not use
table look-ups, this implementation should be close to two times faster than
the AVX implementation.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 562 insertions, 0 deletions

diff --git a/arch/x86/crypto/serpent_avx2_glue.c b/arch/x86/crypto/serpent_avx2_glue.c
new file mode 100644
index 000000000000..23aabc6c20a5
--- /dev/null
+++ b/arch/x86/crypto/serpent_avx2_glue.c
@@ -0,0 +1,562 @@
+/*
+ * Glue Code for x86_64/AVX2 assembler optimized version of Serpent
+ *
+ * Copyright © 2012-2013 Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/crypto.h>
+#include <linux/err.h>
+#include <crypto/algapi.h>
+#include <crypto/ctr.h>
+#include <crypto/lrw.h>
+#include <crypto/xts.h>
+#include <crypto/serpent.h>
+#include <asm/xcr.h>
+#include <asm/xsave.h>
+#include <asm/crypto/serpent-avx.h>
+#include <asm/crypto/ablk_helper.h>
+#include <asm/crypto/glue_helper.h>
+
+#define SERPENT_AVX2_PARALLEL_BLOCKS 16
+
+/* 16-way AVX2 parallel cipher functions */
+asmlinkage void serpent_ecb_enc_16way(struct serpent_ctx *ctx, u8 *dst,
+				      const u8 *src);
+asmlinkage void serpent_ecb_dec_16way(struct serpent_ctx *ctx, u8 *dst,
+				      const u8 *src);
+asmlinkage void serpent_cbc_dec_16way(void *ctx, u128 *dst, const u128 *src);
+
+asmlinkage void serpent_ctr_16way(void *ctx, u128 *dst, const u128 *src,
+				  le128 *iv);
+asmlinkage void serpent_xts_enc_16way(struct serpent_ctx *ctx, u8 *dst,
+				      const u8 *src, le128 *iv);
+asmlinkage void serpent_xts_dec_16way(struct serpent_ctx *ctx, u8 *dst,
+				      const u8 *src, le128 *iv);
+
+static const struct common_glue_ctx serpent_enc = {
+	.num_funcs = 3,
+	.fpu_blocks_limit = 8,
+
+	.funcs = { {
+		.num_blocks = 16,
+		.fn_u = { .ecb = GLUE_FUNC_CAST(serpent_ecb_enc_16way) }
+	}, {
+		.num_blocks = 8,
+		.fn_u = { .ecb = GLUE_FUNC_CAST(serpent_ecb_enc_8way_avx) }
+	}, {
+		.num_blocks = 1,
+		.fn_u = { .ecb = GLUE_FUNC_CAST(__serpent_encrypt) }
+	} }
+};
+
+static const struct common_glue_ctx serpent_ctr = {
+	.num_funcs = 3,
+	.fpu_blocks_limit = 8,
+
+	.funcs = { {
+		.num_blocks = 16,
+		.fn_u = { .ctr = GLUE_CTR_FUNC_CAST(serpent_ctr_16way) }
+	},  {
+		.num_blocks = 8,
+		.fn_u = { .ctr = GLUE_CTR_FUNC_CAST(serpent_ctr_8way_avx) }
+	}, {
+		.num_blocks = 1,
+		.fn_u = { .ctr = GLUE_CTR_FUNC_CAST(__serpent_crypt_ctr) }
+	} }
+};
+
+static const struct common_glue_ctx serpent_enc_xts = {
+	.num_funcs = 3,
+	.fpu_blocks_limit = 8,
+
+	.funcs = { {
+		.num_blocks = 16,
+		.fn_u = { .xts = GLUE_XTS_FUNC_CAST(serpent_xts_enc_16way) }
+	}, {
+		.num_blocks = 8,
+		.fn_u = { .xts = GLUE_XTS_FUNC_CAST(serpent_xts_enc_8way_avx) }
+	}, {
+		.num_blocks = 1,
+		.fn_u = { .xts = GLUE_XTS_FUNC_CAST(serpent_xts_enc) }
+	} }
+};
+
+static const struct common_glue_ctx serpent_dec = {
+	.num_funcs = 3,
+	.fpu_blocks_limit = 8,
+
+	.funcs = { {
+		.num_blocks = 16,
+		.fn_u = { .ecb = GLUE_FUNC_CAST(serpent_ecb_dec_16way) }
+	}, {
+		.num_blocks = 8,
+		.fn_u = { .ecb = GLUE_FUNC_CAST(serpent_ecb_dec_8way_avx) }
+	}, {
+		.num_blocks = 1,
+		.fn_u = { .ecb = GLUE_FUNC_CAST(__serpent_decrypt) }
+	} }
+};
+
+static const struct common_glue_ctx serpent_dec_cbc = {
+	.num_funcs = 3,
+	.fpu_blocks_limit = 8,
+
+	.funcs = { {
+		.num_blocks = 16,
+		.fn_u = { .cbc = GLUE_CBC_FUNC_CAST(serpent_cbc_dec_16way) }
+	}, {
+		.num_blocks = 8,
+		.fn_u = { .cbc = GLUE_CBC_FUNC_CAST(serpent_cbc_dec_8way_avx) }
+	}, {
+		.num_blocks = 1,
+		.fn_u = { .cbc = GLUE_CBC_FUNC_CAST(__serpent_decrypt) }
+	} }
+};
+
+static const struct common_glue_ctx serpent_dec_xts = {
+	.num_funcs = 3,
+	.fpu_blocks_limit = 8,
+
+	.funcs = { {
+		.num_blocks = 16,
+		.fn_u = { .xts = GLUE_XTS_FUNC_CAST(serpent_xts_dec_16way) }
+	}, {
+		.num_blocks = 8,
+		.fn_u = { .xts = GLUE_XTS_FUNC_CAST(serpent_xts_dec_8way_avx) }
+	}, {
+		.num_blocks = 1,
+		.fn_u = { .xts = GLUE_XTS_FUNC_CAST(serpent_xts_dec) }
+	} }
+};
+
+static int ecb_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+		       struct scatterlist *src, unsigned int nbytes)
+{
+	return glue_ecb_crypt_128bit(&serpent_enc, desc, dst, src, nbytes);
+}
+
+static int ecb_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+		       struct scatterlist *src, unsigned int nbytes)
+{
+	return glue_ecb_crypt_128bit(&serpent_dec, desc, dst, src, nbytes);
+}
+
+static int cbc_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+		       struct scatterlist *src, unsigned int nbytes)
+{
+	return glue_cbc_encrypt_128bit(GLUE_FUNC_CAST(__serpent_encrypt), desc,
+				       dst, src, nbytes);
+}
+
+static int cbc_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+		       struct scatterlist *src, unsigned int nbytes)
+{
+	return glue_cbc_decrypt_128bit(&serpent_dec_cbc, desc, dst, src,
+				       nbytes);
+}
+
+static int ctr_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+		     struct scatterlist *src, unsigned int nbytes)
+{
+	return glue_ctr_crypt_128bit(&serpent_ctr, desc, dst, src, nbytes);
+}
+
+static inline bool serpent_fpu_begin(bool fpu_enabled, unsigned int nbytes)
+{
+	/* since reusing AVX functions, starts using FPU at 8 parallel blocks */
+	return glue_fpu_begin(SERPENT_BLOCK_SIZE, 8, NULL, fpu_enabled, nbytes);
+}
+
+static inline void serpent_fpu_end(bool fpu_enabled)
+{
+	glue_fpu_end(fpu_enabled);
+}
+
+struct crypt_priv {
+	struct serpent_ctx *ctx;
+	bool fpu_enabled;
+};
+
+static void encrypt_callback(void *priv, u8 *srcdst, unsigned int nbytes)
+{
+	const unsigned int bsize = SERPENT_BLOCK_SIZE;
+	struct crypt_priv *ctx = priv;
+	int i;
+
+	ctx->fpu_enabled = serpent_fpu_begin(ctx->fpu_enabled, nbytes);
+
+	if (nbytes >= SERPENT_AVX2_PARALLEL_BLOCKS * bsize) {
+		serpent_ecb_enc_16way(ctx->ctx, srcdst, srcdst);
+		srcdst += bsize * SERPENT_AVX2_PARALLEL_BLOCKS;
+		nbytes -= bsize * SERPENT_AVX2_PARALLEL_BLOCKS;
+	}
+
+	while (nbytes >= SERPENT_PARALLEL_BLOCKS * bsize) {
+		serpent_ecb_enc_8way_avx(ctx->ctx, srcdst, srcdst);
+		srcdst += bsize * SERPENT_PARALLEL_BLOCKS;
+		nbytes -= bsize * SERPENT_PARALLEL_BLOCKS;
+	}
+
+	for (i = 0; i < nbytes / bsize; i++, srcdst += bsize)
+		__serpent_encrypt(ctx->ctx, srcdst, srcdst);
+}
+
+static void decrypt_callback(void *priv, u8 *srcdst, unsigned int nbytes)
+{
+	const unsigned int bsize = SERPENT_BLOCK_SIZE;
+	struct crypt_priv *ctx = priv;
+	int i;
+
+	ctx->fpu_enabled = serpent_fpu_begin(ctx->fpu_enabled, nbytes);
+
+	if (nbytes >= SERPENT_AVX2_PARALLEL_BLOCKS * bsize) {
+		serpent_ecb_dec_16way(ctx->ctx, srcdst, srcdst);
+		srcdst += bsize * SERPENT_AVX2_PARALLEL_BLOCKS;
+		nbytes -= bsize * SERPENT_AVX2_PARALLEL_BLOCKS;
+	}
+
+	while (nbytes >= SERPENT_PARALLEL_BLOCKS * bsize) {
+		serpent_ecb_dec_8way_avx(ctx->ctx, srcdst, srcdst);
+		srcdst += bsize * SERPENT_PARALLEL_BLOCKS;
+		nbytes -= bsize * SERPENT_PARALLEL_BLOCKS;
+	}
+
+	for (i = 0; i < nbytes / bsize; i++, srcdst += bsize)
+		__serpent_decrypt(ctx->ctx, srcdst, srcdst);
+}
+
+static int lrw_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+		       struct scatterlist *src, unsigned int nbytes)
+{
+	struct serpent_lrw_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
+	be128 buf[SERPENT_AVX2_PARALLEL_BLOCKS];
+	struct crypt_priv crypt_ctx = {
+		.ctx = &ctx->serpent_ctx,
+		.fpu_enabled = false,
+	};
+	struct lrw_crypt_req req = {
+		.tbuf = buf,
+		.tbuflen = sizeof(buf),
+
+		.table_ctx = &ctx->lrw_table,
+		.crypt_ctx = &crypt_ctx,
+		.crypt_fn = encrypt_callback,
+	};
+	int ret;
+
+	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
+	ret = lrw_crypt(desc, dst, src, nbytes, &req);
+	serpent_fpu_end(crypt_ctx.fpu_enabled);
+
+	return ret;
+}
+
+static int lrw_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+		       struct scatterlist *src, unsigned int nbytes)
+{
+	struct serpent_lrw_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
+	be128 buf[SERPENT_AVX2_PARALLEL_BLOCKS];
+	struct crypt_priv crypt_ctx = {
+		.ctx = &ctx->serpent_ctx,
+		.fpu_enabled = false,
+	};
+	struct lrw_crypt_req req = {
+		.tbuf = buf,
+		.tbuflen = sizeof(buf),
+
+		.table_ctx = &ctx->lrw_table,
+		.crypt_ctx = &crypt_ctx,
+		.crypt_fn = decrypt_callback,
+	};
+	int ret;
+
+	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
+	ret = lrw_crypt(desc, dst, src, nbytes, &req);
+	serpent_fpu_end(crypt_ctx.fpu_enabled);
+
+	return ret;
+}
+
+static int xts_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+		       struct scatterlist *src, unsigned int nbytes)
+{
+	struct serpent_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
+
+	return glue_xts_crypt_128bit(&serpent_enc_xts, desc, dst, src, nbytes,
+				     XTS_TWEAK_CAST(__serpent_encrypt),
+				     &ctx->tweak_ctx, &ctx->crypt_ctx);
+}
+
+static int xts_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+		       struct scatterlist *src, unsigned int nbytes)
+{
+	struct serpent_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
+
+	return glue_xts_crypt_128bit(&serpent_dec_xts, desc, dst, src, nbytes,
+				     XTS_TWEAK_CAST(__serpent_encrypt),
+				     &ctx->tweak_ctx, &ctx->crypt_ctx);
+}
+
+static struct crypto_alg srp_algs[10] = { {
+	.cra_name		= "__ecb-serpent-avx2",
+	.cra_driver_name	= "__driver-ecb-serpent-avx2",
+	.cra_priority		= 0,
+	.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER,
+	.cra_blocksize		= SERPENT_BLOCK_SIZE,
+	.cra_ctxsize		= sizeof(struct serpent_ctx),
+	.cra_alignmask		= 0,
+	.cra_type		= &crypto_blkcipher_type,
+	.cra_module		= THIS_MODULE,
+	.cra_list		= LIST_HEAD_INIT(srp_algs[0].cra_list),
+	.cra_u = {
+		.blkcipher = {
+			.min_keysize	= SERPENT_MIN_KEY_SIZE,
+			.max_keysize	= SERPENT_MAX_KEY_SIZE,
+			.setkey		= serpent_setkey,
+			.encrypt	= ecb_encrypt,
+			.decrypt	= ecb_decrypt,
+		},
+	},
+}, {
+	.cra_name		= "__cbc-serpent-avx2",
+	.cra_driver_name	= "__driver-cbc-serpent-avx2",
+	.cra_priority		= 0,
+	.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER,
+	.cra_blocksize		= SERPENT_BLOCK_SIZE,
+	.cra_ctxsize		= sizeof(struct serpent_ctx),
+	.cra_alignmask		= 0,
+	.cra_type		= &crypto_blkcipher_type,
+	.cra_module		= THIS_MODULE,
+	.cra_list		= LIST_HEAD_INIT(srp_algs[1].cra_list),
+	.cra_u = {
+		.blkcipher = {
+			.min_keysize	= SERPENT_MIN_KEY_SIZE,
+			.max_keysize	= SERPENT_MAX_KEY_SIZE,
+			.setkey		= serpent_setkey,
+			.encrypt	= cbc_encrypt,
+			.decrypt	= cbc_decrypt,
+		},
+	},
+}, {
+	.cra_name		= "__ctr-serpent-avx2",
+	.cra_driver_name	= "__driver-ctr-serpent-avx2",
+	.cra_priority		= 0,
+	.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER,
+	.cra_blocksize		= 1,
+	.cra_ctxsize		= sizeof(struct serpent_ctx),
+	.cra_alignmask		= 0,
+	.cra_type		= &crypto_blkcipher_type,
+	.cra_module		= THIS_MODULE,
+	.cra_list		= LIST_HEAD_INIT(srp_algs[2].cra_list),
+	.cra_u = {
+		.blkcipher = {
+			.min_keysize	= SERPENT_MIN_KEY_SIZE,
+			.max_keysize	= SERPENT_MAX_KEY_SIZE,
+			.ivsize		= SERPENT_BLOCK_SIZE,
+			.setkey		= serpent_setkey,
+			.encrypt	= ctr_crypt,
+			.decrypt	= ctr_crypt,
+		},
+	},
+}, {
+	.cra_name		= "__lrw-serpent-avx2",
+	.cra_driver_name	= "__driver-lrw-serpent-avx2",
+	.cra_priority		= 0,
+	.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER,
+	.cra_blocksize		= SERPENT_BLOCK_SIZE,
+	.cra_ctxsize		= sizeof(struct serpent_lrw_ctx),
+	.cra_alignmask		= 0,
+	.cra_type		= &crypto_blkcipher_type,
+	.cra_module		= THIS_MODULE,
+	.cra_list		= LIST_HEAD_INIT(srp_algs[3].cra_list),
+	.cra_exit		= lrw_serpent_exit_tfm,
+	.cra_u = {
+		.blkcipher = {
+			.min_keysize	= SERPENT_MIN_KEY_SIZE +
+					  SERPENT_BLOCK_SIZE,
+			.max_keysize	= SERPENT_MAX_KEY_SIZE +
+					  SERPENT_BLOCK_SIZE,
+			.ivsize		= SERPENT_BLOCK_SIZE,
+			.setkey		= lrw_serpent_setkey,
+			.encrypt	= lrw_encrypt,
+			.decrypt	= lrw_decrypt,
+		},
+	},
+}, {
+	.cra_name		= "__xts-serpent-avx2",
+	.cra_driver_name	= "__driver-xts-serpent-avx2",
+	.cra_priority		= 0,
+	.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER,
+	.cra_blocksize		= SERPENT_BLOCK_SIZE,
+	.cra_ctxsize		= sizeof(struct serpent_xts_ctx),
+	.cra_alignmask		= 0,
+	.cra_type		= &crypto_blkcipher_type,
+	.cra_module		= THIS_MODULE,
+	.cra_list		= LIST_HEAD_INIT(srp_algs[4].cra_list),
+	.cra_u = {
+		.blkcipher = {
+			.min_keysize	= SERPENT_MIN_KEY_SIZE * 2,
+			.max_keysize	= SERPENT_MAX_KEY_SIZE * 2,
+			.ivsize		= SERPENT_BLOCK_SIZE,
+			.setkey		= xts_serpent_setkey,
+			.encrypt	= xts_encrypt,
+			.decrypt	= xts_decrypt,
+		},
+	},
+}, {
+	.cra_name		= "ecb(serpent)",
+	.cra_driver_name	= "ecb-serpent-avx2",
+	.cra_priority		= 600,
+	.cra_flags		= CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
+	.cra_blocksize		= SERPENT_BLOCK_SIZE,
+	.cra_ctxsize		= sizeof(struct async_helper_ctx),
+	.cra_alignmask		= 0,
+	.cra_type		= &crypto_ablkcipher_type,
+	.cra_module		= THIS_MODULE,
+	.cra_list		= LIST_HEAD_INIT(srp_algs[5].cra_list),
+	.cra_init		= ablk_init,
+	.cra_exit		= ablk_exit,
+	.cra_u = {
+		.ablkcipher = {
+			.min_keysize	= SERPENT_MIN_KEY_SIZE,
+			.max_keysize	= SERPENT_MAX_KEY_SIZE,
+			.setkey		= ablk_set_key,
+			.encrypt	= ablk_encrypt,
+			.decrypt	= ablk_decrypt,
+		},
+	},
+}, {
+	.cra_name		= "cbc(serpent)",
+	.cra_driver_name	= "cbc-serpent-avx2",
+	.cra_priority		= 600,
+	.cra_flags		= CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
+	.cra_blocksize		= SERPENT_BLOCK_SIZE,
+	.cra_ctxsize		= sizeof(struct async_helper_ctx),
+	.cra_alignmask		= 0,
+	.cra_type		= &crypto_ablkcipher_type,
+	.cra_module		= THIS_MODULE,
+	.cra_list		= LIST_HEAD_INIT(srp_algs[6].cra_list),
+	.cra_init		= ablk_init,
+	.cra_exit		= ablk_exit,
+	.cra_u = {
+		.ablkcipher = {
+			.min_keysize	= SERPENT_MIN_KEY_SIZE,
+			.max_keysize	= SERPENT_MAX_KEY_SIZE,
+			.ivsize		= SERPENT_BLOCK_SIZE,
+			.setkey		= ablk_set_key,
+			.encrypt	= __ablk_encrypt,
+			.decrypt	= ablk_decrypt,
+		},
+	},
+}, {
+	.cra_name		= "ctr(serpent)",
+	.cra_driver_name	= "ctr-serpent-avx2",
+	.cra_priority		= 600,
+	.cra_flags		= CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
+	.cra_blocksize		= 1,
+	.cra_ctxsize		= sizeof(struct async_helper_ctx),
+	.cra_alignmask		= 0,
+	.cra_type		= &crypto_ablkcipher_type,
+	.cra_module		= THIS_MODULE,
+	.cra_list		= LIST_HEAD_INIT(srp_algs[7].cra_list),
+	.cra_init		= ablk_init,
+	.cra_exit		= ablk_exit,
+	.cra_u = {
+		.ablkcipher = {
+			.min_keysize	= SERPENT_MIN_KEY_SIZE,
+			.max_keysize	= SERPENT_MAX_KEY_SIZE,
+			.ivsize		= SERPENT_BLOCK_SIZE,
+			.setkey		= ablk_set_key,
+			.encrypt	= ablk_encrypt,
+			.decrypt	= ablk_encrypt,
+			.geniv		= "chainiv",
+		},
+	},
+}, {
+	.cra_name		= "lrw(serpent)",
+	.cra_driver_name	= "lrw-serpent-avx2",
+	.cra_priority		= 600,
+	.cra_flags		= CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
+	.cra_blocksize		= SERPENT_BLOCK_SIZE,
+	.cra_ctxsize		= sizeof(struct async_helper_ctx),
+	.cra_alignmask		= 0,
+	.cra_type		= &crypto_ablkcipher_type,
+	.cra_module		= THIS_MODULE,
+	.cra_list		= LIST_HEAD_INIT(srp_algs[8].cra_list),
+	.cra_init		= ablk_init,
+	.cra_exit		= ablk_exit,
+	.cra_u = {
+		.ablkcipher = {
+			.min_keysize	= SERPENT_MIN_KEY_SIZE +
+					  SERPENT_BLOCK_SIZE,
+			.max_keysize	= SERPENT_MAX_KEY_SIZE +
+					  SERPENT_BLOCK_SIZE,
+			.ivsize		= SERPENT_BLOCK_SIZE,
+			.setkey		= ablk_set_key,
+			.encrypt	= ablk_encrypt,
+			.decrypt	= ablk_decrypt,
+		},
+	},
+}, {
+	.cra_name		= "xts(serpent)",
+	.cra_driver_name	= "xts-serpent-avx2",
+	.cra_priority		= 600,
+	.cra_flags		= CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
+	.cra_blocksize		= SERPENT_BLOCK_SIZE,
+	.cra_ctxsize		= sizeof(struct async_helper_ctx),
+	.cra_alignmask		= 0,
+	.cra_type		= &crypto_ablkcipher_type,
+	.cra_module		= THIS_MODULE,
+	.cra_list		= LIST_HEAD_INIT(srp_algs[9].cra_list),
+	.cra_init		= ablk_init,
+	.cra_exit		= ablk_exit,
+	.cra_u = {
+		.ablkcipher = {
+			.min_keysize	= SERPENT_MIN_KEY_SIZE * 2,
+			.max_keysize	= SERPENT_MAX_KEY_SIZE * 2,
+			.ivsize		= SERPENT_BLOCK_SIZE,
+			.setkey		= ablk_set_key,
+			.encrypt	= ablk_encrypt,
+			.decrypt	= ablk_decrypt,
+		},
+	},
+} };
+
+static int __init init(void)
+{
+	u64 xcr0;
+
+	if (!cpu_has_avx2 || !cpu_has_osxsave) {
+		pr_info("AVX2 instructions are not detected.\n");
+		return -ENODEV;
+	}
+
+	xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK);
+	if ((xcr0 & (XSTATE_SSE | XSTATE_YMM)) != (XSTATE_SSE | XSTATE_YMM)) {
+		pr_info("AVX detected but unusable.\n");
+		return -ENODEV;
+	}
+
+	return crypto_register_algs(srp_algs, ARRAY_SIZE(srp_algs));
+}
+
+static void __exit fini(void)
+{
+	crypto_unregister_algs(srp_algs, ARRAY_SIZE(srp_algs));
+}
+
+module_init(init);
+module_exit(fini);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Serpent Cipher Algorithm, AVX2 optimized");
+MODULE_ALIAS("serpent");
+MODULE_ALIAS("serpent-asm");