linux/arch/x86/crypto/twofish_avx_glue.c

/*
 * Glue Code for AVX assembler version of Twofish Cipher
 *
 * Copyright (C) 2012 Johannes Goetzfried
 *     <Johannes.Goetzfried@informatik.stud.uni-erlangen.de>
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 * USA
 *
 */

#include <linux/module.h>
#include <linux/hardirq.h>
#include <linux/types.h>
#include <linux/crypto.h>
#include <linux/err.h>
#include <crypto/algapi.h>
#include <crypto/twofish.h>
#include <crypto/cryptd.h>
#include <crypto/b128ops.h>
#include <crypto/ctr.h>
#include <crypto/lrw.h>
#include <crypto/xts.h>
#include <asm/i387.h>
#include <asm/xcr.h>
#include <asm/xsave.h>
#include <asm/crypto/twofish.h>
#include <asm/crypto/ablk_helper.h>
#include <asm/crypto/glue_helper.h>
#include <crypto/scatterwalk.h>
#include <linux/workqueue.h>
#include <linux/spinlock.h>

#define TWOFISH_PARALLEL_BLOCKS 8

static inline void twofish_enc_blk_3way(struct twofish_ctx *ctx, u8 *dst,
					const u8 *src)
{
	__twofish_enc_blk_3way(ctx, dst, src, false);
}

/* 8-way parallel cipher functions */
asmlinkage void __twofish_enc_blk_8way(struct twofish_ctx *ctx, u8 *dst,
				       const u8 *src, bool xor);
asmlinkage void twofish_dec_blk_8way(struct twofish_ctx *ctx, u8 *dst,
				     const u8 *src);

static inline void twofish_enc_blk_xway(struct twofish_ctx *ctx, u8 *dst,
					const u8 *src)
{
	__twofish_enc_blk_8way(ctx, dst, src, false);
}

static inline void twofish_enc_blk_xway_xor(struct twofish_ctx *ctx, u8 *dst,
					    const u8 *src)
{
	__twofish_enc_blk_8way(ctx, dst, src, true);
}

static inline void twofish_dec_blk_xway(struct twofish_ctx *ctx, u8 *dst,
					const u8 *src)
{
	twofish_dec_blk_8way(ctx, dst, src);
}

static void twofish_dec_blk_cbc_xway(void *ctx, u128 *dst, const u128 *src)
{
	u128 ivs[TWOFISH_PARALLEL_BLOCKS - 1];
	unsigned int j;

	for (j = 0; j < TWOFISH_PARALLEL_BLOCKS - 1; j++)
		ivs[j] = src[j];

	twofish_dec_blk_xway(ctx, (u8 *)dst, (u8 *)src);

	for (j = 0; j < TWOFISH_PARALLEL_BLOCKS - 1; j++)
		u128_xor(dst + (j + 1), dst + (j + 1), ivs + j);
}

static void twofish_enc_blk_ctr_xway(void *ctx, u128 *dst, const u128 *src,
				     u128 *iv)
{
	be128 ctrblks[TWOFISH_PARALLEL_BLOCKS];
	unsigned int i;

	for (i = 0; i < TWOFISH_PARALLEL_BLOCKS; i++) {
		if (dst != src)
			dst[i] = src[i];

		u128_to_be128(&ctrblks[i], iv);
		u128_inc(iv);
	}

	twofish_enc_blk_xway_xor(ctx, (u8 *)dst, (u8 *)ctrblks);
}

static const struct common_glue_ctx twofish_enc = {
	.num_funcs = 3,
	.fpu_blocks_limit = TWOFISH_PARALLEL_BLOCKS,

	.funcs = { {
		.num_blocks = TWOFISH_PARALLEL_BLOCKS,
		.fn_u = { .ecb = GLUE_FUNC_CAST(twofish_enc_blk_xway) }
	}, {
		.num_blocks = 3,
		.fn_u = { .ecb = GLUE_FUNC_CAST(twofish_enc_blk_3way) }
	}, {
		.num_blocks = 1,
		.fn_u = { .ecb = GLUE_FUNC_CAST(twofish_enc_blk) }
	} }
};

static const struct common_glue_ctx twofish_ctr = {
	.num_funcs = 3,
	.fpu_blocks_limit = TWOFISH_PARALLEL_BLOCKS,

	.funcs = { {
		.num_blocks = TWOFISH_PARALLEL_BLOCKS,
		.fn_u = { .ctr = GLUE_CTR_FUNC_CAST(twofish_enc_blk_ctr_xway) }
	}, {
		.num_blocks = 3,
		.fn_u = { .ctr = GLUE_CTR_FUNC_CAST(twofish_enc_blk_ctr_3way) }
	}, {
		.num_blocks = 1,
		.fn_u = { .ctr = GLUE_CTR_FUNC_CAST(twofish_enc_blk_ctr) }
	} }
};

static const struct common_glue_ctx twofish_dec = {
	.num_funcs = 3,
	.fpu_blocks_limit = TWOFISH_PARALLEL_BLOCKS,

	.funcs = { {
		.num_blocks = TWOFISH_PARALLEL_BLOCKS,
		.fn_u = { .ecb = GLUE_FUNC_CAST(twofish_dec_blk_xway) }
	}, {
		.num_blocks = 3,
		.fn_u = { .ecb = GLUE_FUNC_CAST(twofish_dec_blk_3way) }
	}, {
		.num_blocks = 1,
		.fn_u = { .ecb = GLUE_FUNC_CAST(twofish_dec_blk) }
	} }
};

static const struct common_glue_ctx twofish_dec_cbc = {
	.num_funcs = 3,
	.fpu_blocks_limit = TWOFISH_PARALLEL_BLOCKS,

	.funcs = { {
		.num_blocks = TWOFISH_PARALLEL_BLOCKS,
		.fn_u = { .cbc = GLUE_CBC_FUNC_CAST(twofish_dec_blk_cbc_xway) }
	}, {
		.num_blocks = 3,
		.fn_u = { .cbc = GLUE_CBC_FUNC_CAST(twofish_dec_blk_cbc_3way) }
	}, {
		.num_blocks = 1,
		.fn_u = { .cbc = GLUE_CBC_FUNC_CAST(twofish_dec_blk) }
	} }
};

static int ecb_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
		       struct scatterlist *src, unsigned int nbytes)
{
	return glue_ecb_crypt_128bit(&twofish_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(&twofish_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(twofish_enc_blk), 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(&twofish_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(&twofish_ctr, desc, dst, src, nbytes);
}

static inline bool twofish_fpu_begin(bool fpu_enabled, unsigned int nbytes)
{
	return glue_fpu_begin(TF_BLOCK_SIZE, TWOFISH_PARALLEL_BLOCKS, NULL,
			      fpu_enabled, nbytes);
}

static inline void twofish_fpu_end(bool fpu_enabled)
{
	glue_fpu_end(fpu_enabled);
}

struct crypt_priv {
	struct twofish_ctx *ctx;
	bool fpu_enabled;
};

static void encrypt_callback(void *priv, u8 *srcdst, unsigned int nbytes)
{
	const unsigned int bsize = TF_BLOCK_SIZE;
	struct crypt_priv *ctx = priv;
	int i;

	ctx->fpu_enabled = twofish_fpu_begin(ctx->fpu_enabled, nbytes);

	if (nbytes == bsize * TWOFISH_PARALLEL_BLOCKS) {
		twofish_enc_blk_xway(ctx->ctx, srcdst, srcdst);
		return;
	}

	for (i = 0; i < nbytes / (bsize * 3); i++, srcdst += bsize * 3)
		twofish_enc_blk_3way(ctx->ctx, srcdst, srcdst);

	nbytes %= bsize * 3;

	for (i = 0; i < nbytes / bsize; i++, srcdst += bsize)
		twofish_enc_blk(ctx->ctx, srcdst, srcdst);
}

static void decrypt_callback(void *priv, u8 *srcdst, unsigned int nbytes)
{
	const unsigned int bsize = TF_BLOCK_SIZE;
	struct crypt_priv *ctx = priv;
	int i;

	ctx->fpu_enabled = twofish_fpu_begin(ctx->fpu_enabled, nbytes);

	if (nbytes == bsize * TWOFISH_PARALLEL_BLOCKS) {
		twofish_dec_blk_xway(ctx->ctx, srcdst, srcdst);
		return;
	}

	for (i = 0; i < nbytes / (bsize * 3); i++, srcdst += bsize * 3)
		twofish_dec_blk_3way(ctx->ctx, srcdst, srcdst);

	nbytes %= bsize * 3;

	for (i = 0; i < nbytes / bsize; i++, srcdst += bsize)
		twofish_dec_blk(ctx->ctx, srcdst, srcdst);
}

static int lrw_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
		       struct scatterlist *src, unsigned int nbytes)
{
	struct twofish_lrw_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
	be128 buf[TWOFISH_PARALLEL_BLOCKS];
	struct crypt_priv crypt_ctx = {
		.ctx = &ctx->twofish_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);
	twofish_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 twofish_lrw_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
	be128 buf[TWOFISH_PARALLEL_BLOCKS];
	struct crypt_priv crypt_ctx = {
		.ctx = &ctx->twofish_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);
	twofish_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 twofish_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
	be128 buf[TWOFISH_PARALLEL_BLOCKS];
	struct crypt_priv crypt_ctx = {
		.ctx = &ctx->crypt_ctx,
		.fpu_enabled = false,
	};
	struct xts_crypt_req req = {
		.tbuf = buf,
		.tbuflen = sizeof(buf),

		.tweak_ctx = &ctx->tweak_ctx,
		.tweak_fn = XTS_TWEAK_CAST(twofish_enc_blk),
		.crypt_ctx = &crypt_ctx,
		.crypt_fn = encrypt_callback,
	};
	int ret;

	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
	ret = xts_crypt(desc, dst, src, nbytes, &req);
	twofish_fpu_end(crypt_ctx.fpu_enabled);

	return ret;
}

static int xts_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
		       struct scatterlist *src, unsigned int nbytes)
{
	struct twofish_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
	be128 buf[TWOFISH_PARALLEL_BLOCKS];
	struct crypt_priv crypt_ctx = {
		.ctx = &ctx->crypt_ctx,
		.fpu_enabled = false,
	};
	struct xts_crypt_req req = {
		.tbuf = buf,
		.tbuflen = sizeof(buf),

		.tweak_ctx = &ctx->tweak_ctx,
		.tweak_fn = XTS_TWEAK_CAST(twofish_enc_blk),
		.crypt_ctx = &crypt_ctx,
		.crypt_fn = decrypt_callback,
	};
	int ret;

	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
	ret = xts_crypt(desc, dst, src, nbytes, &req);
	twofish_fpu_end(crypt_ctx.fpu_enabled);

	return ret;
}

static struct crypto_alg twofish_algs[10] = { {
	.cra_name		= "__ecb-twofish-avx",
	.cra_driver_name	= "__driver-ecb-twofish-avx",
	.cra_priority		= 0,
	.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER,
	.cra_blocksize		= TF_BLOCK_SIZE,
	.cra_ctxsize		= sizeof(struct twofish_ctx),
	.cra_alignmask		= 0,
	.cra_type		= &crypto_blkcipher_type,
	.cra_module		= THIS_MODULE,
	.cra_list		= LIST_HEAD_INIT(twofish_algs[0].cra_list),
	.cra_u = {
		.blkcipher = {
			.min_keysize	= TF_MIN_KEY_SIZE,
			.max_keysize	= TF_MAX_KEY_SIZE,
			.setkey		= twofish_setkey,
			.encrypt	= ecb_encrypt,
			.decrypt	= ecb_decrypt,
		},
	},
}, {
	.cra_name		= "__cbc-twofish-avx",
	.cra_driver_name	= "__driver-cbc-twofish-avx",
	.cra_priority		= 0,
	.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER,
	.cra_blocksize		= TF_BLOCK_SIZE,
	.cra_ctxsize		= sizeof(struct twofish_ctx),
	.cra_alignmask		= 0,
	.cra_type		= &crypto_blkcipher_type,
	.cra_module		= THIS_MODULE,
	.cra_list		= LIST_HEAD_INIT(twofish_algs[1].cra_list),
	.cra_u = {
		.blkcipher = {
			.min_keysize	= TF_MIN_KEY_SIZE,
			.max_keysize	= TF_MAX_KEY_SIZE,
			.setkey		= twofish_setkey,
			.encrypt	= cbc_encrypt,
			.decrypt	= cbc_decrypt,
		},
	},
}, {
	.cra_name		= "__ctr-twofish-avx",
	.cra_driver_name	= "__driver-ctr-twofish-avx",
	.cra_priority		= 0,
	.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER,
	.cra_blocksize		= 1,
	.cra_ctxsize		= sizeof(struct twofish_ctx),
	.cra_alignmask		= 0,
	.cra_type		= &crypto_blkcipher_type,
	.cra_module		= THIS_MODULE,
	.cra_list		= LIST_HEAD_INIT(twofish_algs[2].cra_list),
	.cra_u = {
		.blkcipher = {
			.min_keysize	= TF_MIN_KEY_SIZE,
			.max_keysize	= TF_MAX_KEY_SIZE,
			.ivsize		= TF_BLOCK_SIZE,
			.setkey		= twofish_setkey,
			.encrypt	= ctr_crypt,
			.decrypt	= ctr_crypt,
		},
	},
}, {
	.cra_name		= "__lrw-twofish-avx",
	.cra_driver_name	= "__driver-lrw-twofish-avx",
	.cra_priority		= 0,
	.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER,
	.cra_blocksize		= TF_BLOCK_SIZE,
	.cra_ctxsize		= sizeof(struct twofish_lrw_ctx),
	.cra_alignmask		= 0,
	.cra_type		= &crypto_blkcipher_type,
	.cra_module		= THIS_MODULE,
	.cra_list		= LIST_HEAD_INIT(twofish_algs[3].cra_list),
	.cra_exit		= lrw_twofish_exit_tfm,
	.cra_u = {
		.blkcipher = {
			.min_keysize	= TF_MIN_KEY_SIZE +
					  TF_BLOCK_SIZE,
			.max_keysize	= TF_MAX_KEY_SIZE +
					  TF_BLOCK_SIZE,
			.ivsize		= TF_BLOCK_SIZE,
			.setkey		= lrw_twofish_setkey,
			.encrypt	= lrw_encrypt,
			.decrypt	= lrw_decrypt,
		},
	},
}, {
	.cra_name		= "__xts-twofish-avx",
	.cra_driver_name	= "__driver-xts-twofish-avx",
	.cra_priority		= 0,
	.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER,
	.cra_blocksize		= TF_BLOCK_SIZE,
	.cra_ctxsize		= sizeof(struct twofish_xts_ctx),
	.cra_alignmask		= 0,
	.cra_type		= &crypto_blkcipher_type,
	.cra_module		= THIS_MODULE,
	.cra_list		= LIST_HEAD_INIT(twofish_algs[4].cra_list),
	.cra_u = {
		.blkcipher = {
			.min_keysize	= TF_MIN_KEY_SIZE * 2,
			.max_keysize	= TF_MAX_KEY_SIZE * 2,
			.ivsize		= TF_BLOCK_SIZE,
			.setkey		= xts_twofish_setkey,
			.encrypt	= xts_encrypt,
			.decrypt	= xts_decrypt,
		},
	},
}, {
	.cra_name		= "ecb(twofish)",
	.cra_driver_name	= "ecb-twofish-avx",
	.cra_priority		= 400,
	.cra_flags		= CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
	.cra_blocksize		= TF_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(twofish_algs[5].cra_list),
	.cra_init		= ablk_init,
	.cra_exit		= ablk_exit,
	.cra_u = {
		.ablkcipher = {
			.min_keysize	= TF_MIN_KEY_SIZE,
			.max_keysize	= TF_MAX_KEY_SIZE,
			.setkey		= ablk_set_key,
			.encrypt	= ablk_encrypt,
			.decrypt	= ablk_decrypt,
		},
	},
}, {
	.cra_name		= "cbc(twofish)",
	.cra_driver_name	= "cbc-twofish-avx",
	.cra_priority		= 400,
	.cra_flags		= CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
	.cra_blocksize		= TF_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(twofish_algs[6].cra_list),
	.cra_init		= ablk_init,
	.cra_exit		= ablk_exit,
	.cra_u = {
		.ablkcipher = {
			.min_keysize	= TF_MIN_KEY_SIZE,
			.max_keysize	= TF_MAX_KEY_SIZE,
			.ivsize		= TF_BLOCK_SIZE,
			.setkey		= ablk_set_key,
			.encrypt	= __ablk_encrypt,
			.decrypt	= ablk_decrypt,
		},
	},
}, {
	.cra_name		= "ctr(twofish)",
	.cra_driver_name	= "ctr-twofish-avx",
	.cra_priority		= 400,
	.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(twofish_algs[7].cra_list),
	.cra_init		= ablk_init,
	.cra_exit		= ablk_exit,
	.cra_u = {
		.ablkcipher = {
			.min_keysize	= TF_MIN_KEY_SIZE,
			.max_keysize	= TF_MAX_KEY_SIZE,
			.ivsize		= TF_BLOCK_SIZE,
			.setkey		= ablk_set_key,
			.encrypt	= ablk_encrypt,
			.decrypt	= ablk_encrypt,
			.geniv		= "chainiv",
		},
	},
}, {
	.cra_name		= "lrw(twofish)",
	.cra_driver_name	= "lrw-twofish-avx",
	.cra_priority		= 400,
	.cra_flags		= CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
	.cra_blocksize		= TF_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(twofish_algs[8].cra_list),
	.cra_init		= ablk_init,
	.cra_exit		= ablk_exit,
	.cra_u = {
		.ablkcipher = {
			.min_keysize	= TF_MIN_KEY_SIZE +
					  TF_BLOCK_SIZE,
			.max_keysize	= TF_MAX_KEY_SIZE +
					  TF_BLOCK_SIZE,
			.ivsize		= TF_BLOCK_SIZE,
			.setkey		= ablk_set_key,
			.encrypt	= ablk_encrypt,
			.decrypt	= ablk_decrypt,
		},
	},
}, {
	.cra_name		= "xts(twofish)",
	.cra_driver_name	= "xts-twofish-avx",
	.cra_priority		= 400,
	.cra_flags		= CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
	.cra_blocksize		= TF_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(twofish_algs[9].cra_list),
	.cra_init		= ablk_init,
	.cra_exit		= ablk_exit,
	.cra_u = {
		.ablkcipher = {
			.min_keysize	= TF_MIN_KEY_SIZE * 2,
			.max_keysize	= TF_MAX_KEY_SIZE * 2,
			.ivsize		= TF_BLOCK_SIZE,
			.setkey		= ablk_set_key,
			.encrypt	= ablk_encrypt,
			.decrypt	= ablk_decrypt,
		},
	},
} };

static int __init twofish_init(void)
{
	u64 xcr0;

	if (!cpu_has_avx || !cpu_has_osxsave) {
		printk(KERN_INFO "AVX instructions are not detected.\n");
		return -ENODEV;
	}

	xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK);
	if ((xcr0 & (XSTATE_SSE | XSTATE_YMM)) != (XSTATE_SSE | XSTATE_YMM)) {
		printk(KERN_INFO "AVX detected but unusable.\n");
		return -ENODEV;
	}

	return crypto_register_algs(twofish_algs, ARRAY_SIZE(twofish_algs));
}

static void __exit twofish_exit(void)
{
	crypto_unregister_algs(twofish_algs, ARRAY_SIZE(twofish_algs));
}

module_init(twofish_init);
module_exit(twofish_exit);

MODULE_DESCRIPTION("Twofish Cipher Algorithm, AVX optimized");
MODULE_LICENSE("GPL");
MODULE_ALIAS("twofish");