arch/arm/crypto/aesbs-glue.c - codeaurora/cp-linux - Gitiles

 /*
  * linux/arch/arm/crypto/aesbs-glue.c - glue code for NEON bit sliced AES
  *
  * Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */

 #include <asm/neon.h>
 #include <crypto/aes.h>
 #include <crypto/ablk_helper.h>
 #include <crypto/algapi.h>
 #include <linux/module.h>

 #include "aes_glue.h"

 #define BIT_SLICED_KEY_MAXSIZE	(128 * (AES_MAXNR - 1) + 2 * AES_BLOCK_SIZE)

 struct BS_KEY {
 	struct AES_KEY	rk;
 	int		converted;
 	u8 __aligned(8)	bs[BIT_SLICED_KEY_MAXSIZE];
 } __aligned(8);

 asmlinkage void bsaes_enc_key_convert(u8 out[], struct AES_KEY const *in);
 asmlinkage void bsaes_dec_key_convert(u8 out[], struct AES_KEY const *in);

 asmlinkage void bsaes_cbc_encrypt(u8 const in[], u8 out[], u32 bytes,
 				  struct BS_KEY *key, u8 iv[]);

 asmlinkage void bsaes_ctr32_encrypt_blocks(u8 const in[], u8 out[], u32 blocks,
 					   struct BS_KEY *key, u8 const iv[]);

 asmlinkage void bsaes_xts_encrypt(u8 const in[], u8 out[], u32 bytes,
 				  struct BS_KEY *key, u8 tweak[]);

 asmlinkage void bsaes_xts_decrypt(u8 const in[], u8 out[], u32 bytes,
 				  struct BS_KEY *key, u8 tweak[]);

 struct aesbs_cbc_ctx {
 	struct AES_KEY	enc;
 	struct BS_KEY	dec;
 };

 struct aesbs_ctr_ctx {
 	struct BS_KEY	enc;
 };

 struct aesbs_xts_ctx {
 	struct BS_KEY	enc;
 	struct BS_KEY	dec;
 	struct AES_KEY	twkey;
 };

 static int aesbs_cbc_set_key(struct crypto_tfm *tfm, const u8 *in_key,
 			     unsigned int key_len)
 {
 	struct aesbs_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
 	int bits = key_len * 8;

 	if (private_AES_set_encrypt_key(in_key, bits, &ctx->enc)) {
 		tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
 		return -EINVAL;
 	}
 	ctx->dec.rk = ctx->enc;
 	private_AES_set_decrypt_key(in_key, bits, &ctx->dec.rk);
 	ctx->dec.converted = 0;
 	return 0;
 }

 static int aesbs_ctr_set_key(struct crypto_tfm *tfm, const u8 *in_key,
 			     unsigned int key_len)
 {
 	struct aesbs_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
 	int bits = key_len * 8;

 	if (private_AES_set_encrypt_key(in_key, bits, &ctx->enc.rk)) {
 		tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
 		return -EINVAL;
 	}
 	ctx->enc.converted = 0;
 	return 0;
 }

 static int aesbs_xts_set_key(struct crypto_tfm *tfm, const u8 *in_key,
 			     unsigned int key_len)
 {
 	struct aesbs_xts_ctx *ctx = crypto_tfm_ctx(tfm);
 	int bits = key_len * 4;

 	if (private_AES_set_encrypt_key(in_key, bits, &ctx->enc.rk)) {
 		tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
 		return -EINVAL;
 	}
 	ctx->dec.rk = ctx->enc.rk;
 	private_AES_set_decrypt_key(in_key, bits, &ctx->dec.rk);
 	private_AES_set_encrypt_key(in_key + key_len / 2, bits, &ctx->twkey);
 	ctx->enc.converted = ctx->dec.converted = 0;
 	return 0;
 }

 static int aesbs_cbc_encrypt(struct blkcipher_desc *desc,
 			     struct scatterlist *dst,
 			     struct scatterlist *src, unsigned int nbytes)
 {
 	struct aesbs_cbc_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
 	struct blkcipher_walk walk;
 	int err;

 	blkcipher_walk_init(&walk, dst, src, nbytes);
 	err = blkcipher_walk_virt(desc, &walk);

 	while (walk.nbytes) {
 		u32 blocks = walk.nbytes / AES_BLOCK_SIZE;
 		u8 *src = walk.src.virt.addr;

 		if (walk.dst.virt.addr == walk.src.virt.addr) {
 			u8 *iv = walk.iv;

 			do {
 				crypto_xor(src, iv, AES_BLOCK_SIZE);
 				AES_encrypt(src, src, &ctx->enc);
 				iv = src;
 				src += AES_BLOCK_SIZE;
 			} while (--blocks);
 			memcpy(walk.iv, iv, AES_BLOCK_SIZE);
 		} else {
 			u8 *dst = walk.dst.virt.addr;

 			do {
 				crypto_xor(walk.iv, src, AES_BLOCK_SIZE);
 				AES_encrypt(walk.iv, dst, &ctx->enc);
 				memcpy(walk.iv, dst, AES_BLOCK_SIZE);
 				src += AES_BLOCK_SIZE;
 				dst += AES_BLOCK_SIZE;
 			} while (--blocks);
 		}
 		err = blkcipher_walk_done(desc, &walk, walk.nbytes % AES_BLOCK_SIZE);
 	}
 	return err;
 }

 static int aesbs_cbc_decrypt(struct blkcipher_desc *desc,
 			     struct scatterlist *dst,
 			     struct scatterlist *src, unsigned int nbytes)
 {
 	struct aesbs_cbc_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
 	struct blkcipher_walk walk;
 	int err;

 	blkcipher_walk_init(&walk, dst, src, nbytes);
 	err = blkcipher_walk_virt_block(desc, &walk, 8 * AES_BLOCK_SIZE);

 	while ((walk.nbytes / AES_BLOCK_SIZE) >= 8) {
 		kernel_neon_begin();
 		bsaes_cbc_encrypt(walk.src.virt.addr, walk.dst.virt.addr,
 				  walk.nbytes, &ctx->dec, walk.iv);
 		kernel_neon_end();
 		err = blkcipher_walk_done(desc, &walk, walk.nbytes % AES_BLOCK_SIZE);
 	}
 	while (walk.nbytes) {
 		u32 blocks = walk.nbytes / AES_BLOCK_SIZE;
 		u8 *dst = walk.dst.virt.addr;
 		u8 *src = walk.src.virt.addr;
 		u8 bk[2][AES_BLOCK_SIZE];
 		u8 *iv = walk.iv;

 		do {
 			if (walk.dst.virt.addr == walk.src.virt.addr)
 				memcpy(bk[blocks & 1], src, AES_BLOCK_SIZE);

 			AES_decrypt(src, dst, &ctx->dec.rk);
 			crypto_xor(dst, iv, AES_BLOCK_SIZE);

 			if (walk.dst.virt.addr == walk.src.virt.addr)
 				iv = bk[blocks & 1];
 			else
 				iv = src;

 			dst += AES_BLOCK_SIZE;
 			src += AES_BLOCK_SIZE;
 		} while (--blocks);
 		err = blkcipher_walk_done(desc, &walk, walk.nbytes % AES_BLOCK_SIZE);
 	}
 	return err;
 }

 static void inc_be128_ctr(__be32 ctr[], u32 addend)
 {
 	int i;

 	for (i = 3; i >= 0; i--, addend = 1) {
 		u32 n = be32_to_cpu(ctr[i]) + addend;

 		ctr[i] = cpu_to_be32(n);
 		if (n >= addend)
 			break;
 	}
 }

 static int aesbs_ctr_encrypt(struct blkcipher_desc *desc,
 			     struct scatterlist *dst, struct scatterlist *src,
 			     unsigned int nbytes)
 {
 	struct aesbs_ctr_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
 	struct blkcipher_walk walk;
 	u32 blocks;
 	int err;

 	blkcipher_walk_init(&walk, dst, src, nbytes);
 	err = blkcipher_walk_virt_block(desc, &walk, 8 * AES_BLOCK_SIZE);

 	while ((blocks = walk.nbytes / AES_BLOCK_SIZE)) {
 		u32 tail = walk.nbytes % AES_BLOCK_SIZE;
 		__be32 *ctr = (__be32 *)walk.iv;
 		u32 headroom = UINT_MAX - be32_to_cpu(ctr[3]);

 		/* avoid 32 bit counter overflow in the NEON code */
 		if (unlikely(headroom < blocks)) {
 			blocks = headroom + 1;
 			tail = walk.nbytes - blocks * AES_BLOCK_SIZE;
 		}
 		kernel_neon_begin();
 		bsaes_ctr32_encrypt_blocks(walk.src.virt.addr,
 					   walk.dst.virt.addr, blocks,
 					   &ctx->enc, walk.iv);
 		kernel_neon_end();
 		inc_be128_ctr(ctr, blocks);

 		nbytes -= blocks * AES_BLOCK_SIZE;
 		if (nbytes && nbytes == tail && nbytes <= AES_BLOCK_SIZE)
 			break;

 		err = blkcipher_walk_done(desc, &walk, tail);
 	}
 	if (walk.nbytes) {
 		u8 *tdst = walk.dst.virt.addr + blocks * AES_BLOCK_SIZE;
 		u8 *tsrc = walk.src.virt.addr + blocks * AES_BLOCK_SIZE;
 		u8 ks[AES_BLOCK_SIZE];

 		AES_encrypt(walk.iv, ks, &ctx->enc.rk);
 		if (tdst != tsrc)
 			memcpy(tdst, tsrc, nbytes);
 		crypto_xor(tdst, ks, nbytes);
 		err = blkcipher_walk_done(desc, &walk, 0);
 	}
 	return err;
 }

 static int aesbs_xts_encrypt(struct blkcipher_desc *desc,
 			     struct scatterlist *dst,
 			     struct scatterlist *src, unsigned int nbytes)
 {
 	struct aesbs_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
 	struct blkcipher_walk walk;
 	int err;

 	blkcipher_walk_init(&walk, dst, src, nbytes);
 	err = blkcipher_walk_virt_block(desc, &walk, 8 * AES_BLOCK_SIZE);

 	/* generate the initial tweak */
 	AES_encrypt(walk.iv, walk.iv, &ctx->twkey);

 	while (walk.nbytes) {
 		kernel_neon_begin();
 		bsaes_xts_encrypt(walk.src.virt.addr, walk.dst.virt.addr,
 				  walk.nbytes, &ctx->enc, walk.iv);
 		kernel_neon_end();
 		err = blkcipher_walk_done(desc, &walk, walk.nbytes % AES_BLOCK_SIZE);
 	}
 	return err;
 }

 static int aesbs_xts_decrypt(struct blkcipher_desc *desc,
 			     struct scatterlist *dst,
 			     struct scatterlist *src, unsigned int nbytes)
 {
 	struct aesbs_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
 	struct blkcipher_walk walk;
 	int err;

 	blkcipher_walk_init(&walk, dst, src, nbytes);
 	err = blkcipher_walk_virt_block(desc, &walk, 8 * AES_BLOCK_SIZE);

 	/* generate the initial tweak */
 	AES_encrypt(walk.iv, walk.iv, &ctx->twkey);

 	while (walk.nbytes) {
 		kernel_neon_begin();
 		bsaes_xts_decrypt(walk.src.virt.addr, walk.dst.virt.addr,
 				  walk.nbytes, &ctx->dec, walk.iv);
 		kernel_neon_end();
 		err = blkcipher_walk_done(desc, &walk, walk.nbytes % AES_BLOCK_SIZE);
 	}
 	return err;
 }

 static struct crypto_alg aesbs_algs[] = { {
 	.cra_name		= "__cbc-aes-neonbs",
 	.cra_driver_name	= "__driver-cbc-aes-neonbs",
 	.cra_priority		= 0,
 	.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER |
 				  CRYPTO_ALG_INTERNAL,
 	.cra_blocksize		= AES_BLOCK_SIZE,
 	.cra_ctxsize		= sizeof(struct aesbs_cbc_ctx),
 	.cra_alignmask		= 7,
 	.cra_type		= &crypto_blkcipher_type,
 	.cra_module		= THIS_MODULE,
 	.cra_blkcipher = {
 		.min_keysize	= AES_MIN_KEY_SIZE,
 		.max_keysize	= AES_MAX_KEY_SIZE,
 		.ivsize		= AES_BLOCK_SIZE,
 		.setkey		= aesbs_cbc_set_key,
 		.encrypt	= aesbs_cbc_encrypt,
 		.decrypt	= aesbs_cbc_decrypt,
 	},
 }, {
 	.cra_name		= "__ctr-aes-neonbs",
 	.cra_driver_name	= "__driver-ctr-aes-neonbs",
 	.cra_priority		= 0,
 	.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER |
 				  CRYPTO_ALG_INTERNAL,
 	.cra_blocksize		= 1,
 	.cra_ctxsize		= sizeof(struct aesbs_ctr_ctx),
 	.cra_alignmask		= 7,
 	.cra_type		= &crypto_blkcipher_type,
 	.cra_module		= THIS_MODULE,
 	.cra_blkcipher = {
 		.min_keysize	= AES_MIN_KEY_SIZE,
 		.max_keysize	= AES_MAX_KEY_SIZE,
 		.ivsize		= AES_BLOCK_SIZE,
 		.setkey		= aesbs_ctr_set_key,
 		.encrypt	= aesbs_ctr_encrypt,
 		.decrypt	= aesbs_ctr_encrypt,
 	},
 }, {
 	.cra_name		= "__xts-aes-neonbs",
 	.cra_driver_name	= "__driver-xts-aes-neonbs",
 	.cra_priority		= 0,
 	.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER |
 				  CRYPTO_ALG_INTERNAL,
 	.cra_blocksize		= AES_BLOCK_SIZE,
 	.cra_ctxsize		= sizeof(struct aesbs_xts_ctx),
 	.cra_alignmask		= 7,
 	.cra_type		= &crypto_blkcipher_type,
 	.cra_module		= THIS_MODULE,
 	.cra_blkcipher = {
 		.min_keysize	= 2 * AES_MIN_KEY_SIZE,
 		.max_keysize	= 2 * AES_MAX_KEY_SIZE,
 		.ivsize		= AES_BLOCK_SIZE,
 		.setkey		= aesbs_xts_set_key,
 		.encrypt	= aesbs_xts_encrypt,
 		.decrypt	= aesbs_xts_decrypt,
 	},
 }, {
 	.cra_name		= "cbc(aes)",
 	.cra_driver_name	= "cbc-aes-neonbs",
 	.cra_priority		= 250,
 	.cra_flags		= CRYPTO_ALG_TYPE_ABLKCIPHER|CRYPTO_ALG_ASYNC,
 	.cra_blocksize		= AES_BLOCK_SIZE,
 	.cra_ctxsize		= sizeof(struct async_helper_ctx),
 	.cra_alignmask		= 7,
 	.cra_type		= &crypto_ablkcipher_type,
 	.cra_module		= THIS_MODULE,
 	.cra_init		= ablk_init,
 	.cra_exit		= ablk_exit,
 	.cra_ablkcipher = {
 		.min_keysize	= AES_MIN_KEY_SIZE,
 		.max_keysize	= AES_MAX_KEY_SIZE,
 		.ivsize		= AES_BLOCK_SIZE,
 		.setkey		= ablk_set_key,
 		.encrypt	= __ablk_encrypt,
 		.decrypt	= ablk_decrypt,
 	}
 }, {
 	.cra_name		= "ctr(aes)",
 	.cra_driver_name	= "ctr-aes-neonbs",
 	.cra_priority		= 250,
 	.cra_flags		= CRYPTO_ALG_TYPE_ABLKCIPHER|CRYPTO_ALG_ASYNC,
 	.cra_blocksize		= 1,
 	.cra_ctxsize		= sizeof(struct async_helper_ctx),
 	.cra_alignmask		= 7,
 	.cra_type		= &crypto_ablkcipher_type,
 	.cra_module		= THIS_MODULE,
 	.cra_init		= ablk_init,
 	.cra_exit		= ablk_exit,
 	.cra_ablkcipher = {
 		.min_keysize	= AES_MIN_KEY_SIZE,
 		.max_keysize	= AES_MAX_KEY_SIZE,
 		.ivsize		= AES_BLOCK_SIZE,
 		.setkey		= ablk_set_key,
 		.encrypt	= ablk_encrypt,
 		.decrypt	= ablk_decrypt,
 	}
 }, {
 	.cra_name		= "xts(aes)",
 	.cra_driver_name	= "xts-aes-neonbs",
 	.cra_priority		= 250,
 	.cra_flags		= CRYPTO_ALG_TYPE_ABLKCIPHER|CRYPTO_ALG_ASYNC,
 	.cra_blocksize		= AES_BLOCK_SIZE,
 	.cra_ctxsize		= sizeof(struct async_helper_ctx),
 	.cra_alignmask		= 7,
 	.cra_type		= &crypto_ablkcipher_type,
 	.cra_module		= THIS_MODULE,
 	.cra_init		= ablk_init,
 	.cra_exit		= ablk_exit,
 	.cra_ablkcipher = {
 		.min_keysize	= 2 * AES_MIN_KEY_SIZE,
 		.max_keysize	= 2 * AES_MAX_KEY_SIZE,
 		.ivsize		= AES_BLOCK_SIZE,
 		.setkey		= ablk_set_key,
 		.encrypt	= ablk_encrypt,
 		.decrypt	= ablk_decrypt,
 	}
 } };

 static int __init aesbs_mod_init(void)
 {
 	if (!cpu_has_neon())
 		return -ENODEV;

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

 static void __exit aesbs_mod_exit(void)
 {
 	crypto_unregister_algs(aesbs_algs, ARRAY_SIZE(aesbs_algs));
 }

 module_init(aesbs_mod_init);
 module_exit(aesbs_mod_exit);

 MODULE_DESCRIPTION("Bit sliced AES in CBC/CTR/XTS modes using NEON");
 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
 MODULE_LICENSE("GPL");
	/*
	* linux/arch/arm/crypto/aesbs-glue.c - glue code for NEON bit sliced AES
	*
	* Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*/

	#include <asm/neon.h>
	#include <crypto/aes.h>
	#include <crypto/ablk_helper.h>
	#include <crypto/algapi.h>
	#include <linux/module.h>

	#include "aes_glue.h"

	#define BIT_SLICED_KEY_MAXSIZE (128 * (AES_MAXNR - 1) + 2 * AES_BLOCK_SIZE)

	struct BS_KEY {
	struct AES_KEY rk;
	int converted;
	u8 __aligned(8) bs[BIT_SLICED_KEY_MAXSIZE];
	} __aligned(8);

	asmlinkage void bsaes_enc_key_convert(u8 out[], struct AES_KEY const *in);
	asmlinkage void bsaes_dec_key_convert(u8 out[], struct AES_KEY const *in);

	asmlinkage void bsaes_cbc_encrypt(u8 const in[], u8 out[], u32 bytes,
	struct BS_KEY *key, u8 iv[]);

	asmlinkage void bsaes_ctr32_encrypt_blocks(u8 const in[], u8 out[], u32 blocks,
	struct BS_KEY *key, u8 const iv[]);

	asmlinkage void bsaes_xts_encrypt(u8 const in[], u8 out[], u32 bytes,
	struct BS_KEY *key, u8 tweak[]);

	asmlinkage void bsaes_xts_decrypt(u8 const in[], u8 out[], u32 bytes,
	struct BS_KEY *key, u8 tweak[]);

	struct aesbs_cbc_ctx {
	struct AES_KEY enc;
	struct BS_KEY dec;
	};

	struct aesbs_ctr_ctx {
	struct BS_KEY enc;
	};

	struct aesbs_xts_ctx {
	struct BS_KEY enc;
	struct BS_KEY dec;
	struct AES_KEY twkey;
	};

	static int aesbs_cbc_set_key(struct crypto_tfm tfm, const u8 in_key,
	unsigned int key_len)
	{
	struct aesbs_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
	int bits = key_len * 8;

	if (private_AES_set_encrypt_key(in_key, bits, &ctx->enc)) {
	tfm->crt_flags \|= CRYPTO_TFM_RES_BAD_KEY_LEN;
	return -EINVAL;
	}
	ctx->dec.rk = ctx->enc;
	private_AES_set_decrypt_key(in_key, bits, &ctx->dec.rk);
	ctx->dec.converted = 0;
	return 0;
	}

	static int aesbs_ctr_set_key(struct crypto_tfm tfm, const u8 in_key,
	unsigned int key_len)
	{
	struct aesbs_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
	int bits = key_len * 8;

	if (private_AES_set_encrypt_key(in_key, bits, &ctx->enc.rk)) {
	tfm->crt_flags \|= CRYPTO_TFM_RES_BAD_KEY_LEN;
	return -EINVAL;
	}
	ctx->enc.converted = 0;
	return 0;
	}

	static int aesbs_xts_set_key(struct crypto_tfm tfm, const u8 in_key,
	unsigned int key_len)
	{
	struct aesbs_xts_ctx *ctx = crypto_tfm_ctx(tfm);
	int bits = key_len * 4;

	if (private_AES_set_encrypt_key(in_key, bits, &ctx->enc.rk)) {
	tfm->crt_flags \|= CRYPTO_TFM_RES_BAD_KEY_LEN;
	return -EINVAL;
	}
	ctx->dec.rk = ctx->enc.rk;
	private_AES_set_decrypt_key(in_key, bits, &ctx->dec.rk);
	private_AES_set_encrypt_key(in_key + key_len / 2, bits, &ctx->twkey);
	ctx->enc.converted = ctx->dec.converted = 0;
	return 0;
	}

	static int aesbs_cbc_encrypt(struct blkcipher_desc *desc,
	struct scatterlist *dst,
	struct scatterlist *src, unsigned int nbytes)
	{
	struct aesbs_cbc_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
	struct blkcipher_walk walk;
	int err;

	blkcipher_walk_init(&walk, dst, src, nbytes);
	err = blkcipher_walk_virt(desc, &walk);

	while (walk.nbytes) {
	u32 blocks = walk.nbytes / AES_BLOCK_SIZE;
	u8 *src = walk.src.virt.addr;

	if (walk.dst.virt.addr == walk.src.virt.addr) {
	u8 *iv = walk.iv;

	do {
	crypto_xor(src, iv, AES_BLOCK_SIZE);
	AES_encrypt(src, src, &ctx->enc);
	iv = src;
	src += AES_BLOCK_SIZE;
	} while (--blocks);
	memcpy(walk.iv, iv, AES_BLOCK_SIZE);
	} else {
	u8 *dst = walk.dst.virt.addr;

	do {
	crypto_xor(walk.iv, src, AES_BLOCK_SIZE);
	AES_encrypt(walk.iv, dst, &ctx->enc);
	memcpy(walk.iv, dst, AES_BLOCK_SIZE);
	src += AES_BLOCK_SIZE;
	dst += AES_BLOCK_SIZE;
	} while (--blocks);
	}
	err = blkcipher_walk_done(desc, &walk, walk.nbytes % AES_BLOCK_SIZE);
	}
	return err;
	}

	static int aesbs_cbc_decrypt(struct blkcipher_desc *desc,
	struct scatterlist *dst,
	struct scatterlist *src, unsigned int nbytes)
	{
	struct aesbs_cbc_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
	struct blkcipher_walk walk;
	int err;

	blkcipher_walk_init(&walk, dst, src, nbytes);
	err = blkcipher_walk_virt_block(desc, &walk, 8 * AES_BLOCK_SIZE);

	while ((walk.nbytes / AES_BLOCK_SIZE) >= 8) {
	kernel_neon_begin();
	bsaes_cbc_encrypt(walk.src.virt.addr, walk.dst.virt.addr,
	walk.nbytes, &ctx->dec, walk.iv);
	kernel_neon_end();
	err = blkcipher_walk_done(desc, &walk, walk.nbytes % AES_BLOCK_SIZE);
	}
	while (walk.nbytes) {
	u32 blocks = walk.nbytes / AES_BLOCK_SIZE;
	u8 *dst = walk.dst.virt.addr;
	u8 *src = walk.src.virt.addr;
	u8 bk[2][AES_BLOCK_SIZE];
	u8 *iv = walk.iv;

	do {
	if (walk.dst.virt.addr == walk.src.virt.addr)
	memcpy(bk[blocks & 1], src, AES_BLOCK_SIZE);

	AES_decrypt(src, dst, &ctx->dec.rk);
	crypto_xor(dst, iv, AES_BLOCK_SIZE);

	if (walk.dst.virt.addr == walk.src.virt.addr)
	iv = bk[blocks & 1];
	else
	iv = src;

	dst += AES_BLOCK_SIZE;
	src += AES_BLOCK_SIZE;
	} while (--blocks);
	err = blkcipher_walk_done(desc, &walk, walk.nbytes % AES_BLOCK_SIZE);
	}
	return err;
	}

	static void inc_be128_ctr(__be32 ctr[], u32 addend)
	{
	int i;

	for (i = 3; i >= 0; i--, addend = 1) {
	u32 n = be32_to_cpu(ctr[i]) + addend;

	ctr[i] = cpu_to_be32(n);
	if (n >= addend)
	break;
	}
	}

	static int aesbs_ctr_encrypt(struct blkcipher_desc *desc,
	struct scatterlist dst, struct scatterlist src,
	unsigned int nbytes)
	{
	struct aesbs_ctr_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
	struct blkcipher_walk walk;
	u32 blocks;
	int err;

	blkcipher_walk_init(&walk, dst, src, nbytes);
	err = blkcipher_walk_virt_block(desc, &walk, 8 * AES_BLOCK_SIZE);

	while ((blocks = walk.nbytes / AES_BLOCK_SIZE)) {
	u32 tail = walk.nbytes % AES_BLOCK_SIZE;
	__be32 ctr = (__be32 )walk.iv;
	u32 headroom = UINT_MAX - be32_to_cpu(ctr[3]);

	/* avoid 32 bit counter overflow in the NEON code */
	if (unlikely(headroom < blocks)) {
	blocks = headroom + 1;
	tail = walk.nbytes - blocks * AES_BLOCK_SIZE;
	}
	kernel_neon_begin();
	bsaes_ctr32_encrypt_blocks(walk.src.virt.addr,
	walk.dst.virt.addr, blocks,
	&ctx->enc, walk.iv);
	kernel_neon_end();
	inc_be128_ctr(ctr, blocks);

	nbytes -= blocks * AES_BLOCK_SIZE;
	if (nbytes && nbytes == tail && nbytes <= AES_BLOCK_SIZE)
	break;

	err = blkcipher_walk_done(desc, &walk, tail);
	}
	if (walk.nbytes) {
	u8 tdst = walk.dst.virt.addr + blocks AES_BLOCK_SIZE;
	u8 tsrc = walk.src.virt.addr + blocks AES_BLOCK_SIZE;
	u8 ks[AES_BLOCK_SIZE];

	AES_encrypt(walk.iv, ks, &ctx->enc.rk);
	if (tdst != tsrc)
	memcpy(tdst, tsrc, nbytes);
	crypto_xor(tdst, ks, nbytes);
	err = blkcipher_walk_done(desc, &walk, 0);
	}
	return err;
	}

	static int aesbs_xts_encrypt(struct blkcipher_desc *desc,
	struct scatterlist *dst,
	struct scatterlist *src, unsigned int nbytes)
	{
	struct aesbs_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
	struct blkcipher_walk walk;
	int err;

	blkcipher_walk_init(&walk, dst, src, nbytes);
	err = blkcipher_walk_virt_block(desc, &walk, 8 * AES_BLOCK_SIZE);

	/* generate the initial tweak */
	AES_encrypt(walk.iv, walk.iv, &ctx->twkey);

	while (walk.nbytes) {
	kernel_neon_begin();
	bsaes_xts_encrypt(walk.src.virt.addr, walk.dst.virt.addr,
	walk.nbytes, &ctx->enc, walk.iv);
	kernel_neon_end();
	err = blkcipher_walk_done(desc, &walk, walk.nbytes % AES_BLOCK_SIZE);
	}
	return err;
	}

	static int aesbs_xts_decrypt(struct blkcipher_desc *desc,
	struct scatterlist *dst,
	struct scatterlist *src, unsigned int nbytes)
	{
	struct aesbs_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
	struct blkcipher_walk walk;
	int err;

	blkcipher_walk_init(&walk, dst, src, nbytes);
	err = blkcipher_walk_virt_block(desc, &walk, 8 * AES_BLOCK_SIZE);

	/* generate the initial tweak */
	AES_encrypt(walk.iv, walk.iv, &ctx->twkey);

	while (walk.nbytes) {
	kernel_neon_begin();
	bsaes_xts_decrypt(walk.src.virt.addr, walk.dst.virt.addr,
	walk.nbytes, &ctx->dec, walk.iv);
	kernel_neon_end();
	err = blkcipher_walk_done(desc, &walk, walk.nbytes % AES_BLOCK_SIZE);
	}
	return err;
	}

	static struct crypto_alg aesbs_algs[] = { {
	.cra_name = "__cbc-aes-neonbs",
	.cra_driver_name = "__driver-cbc-aes-neonbs",
	.cra_priority = 0,
	.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER \|
	CRYPTO_ALG_INTERNAL,
	.cra_blocksize = AES_BLOCK_SIZE,
	.cra_ctxsize = sizeof(struct aesbs_cbc_ctx),
	.cra_alignmask = 7,
	.cra_type = &crypto_blkcipher_type,
	.cra_module = THIS_MODULE,
	.cra_blkcipher = {
	.min_keysize = AES_MIN_KEY_SIZE,
	.max_keysize = AES_MAX_KEY_SIZE,
	.ivsize = AES_BLOCK_SIZE,
	.setkey = aesbs_cbc_set_key,
	.encrypt = aesbs_cbc_encrypt,
	.decrypt = aesbs_cbc_decrypt,
	},
	}, {
	.cra_name = "__ctr-aes-neonbs",
	.cra_driver_name = "__driver-ctr-aes-neonbs",
	.cra_priority = 0,
	.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER \|
	CRYPTO_ALG_INTERNAL,
	.cra_blocksize = 1,
	.cra_ctxsize = sizeof(struct aesbs_ctr_ctx),
	.cra_alignmask = 7,
	.cra_type = &crypto_blkcipher_type,
	.cra_module = THIS_MODULE,
	.cra_blkcipher = {
	.min_keysize = AES_MIN_KEY_SIZE,
	.max_keysize = AES_MAX_KEY_SIZE,
	.ivsize = AES_BLOCK_SIZE,
	.setkey = aesbs_ctr_set_key,
	.encrypt = aesbs_ctr_encrypt,
	.decrypt = aesbs_ctr_encrypt,
	},
	}, {
	.cra_name = "__xts-aes-neonbs",
	.cra_driver_name = "__driver-xts-aes-neonbs",
	.cra_priority = 0,
	.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER \|
	CRYPTO_ALG_INTERNAL,
	.cra_blocksize = AES_BLOCK_SIZE,
	.cra_ctxsize = sizeof(struct aesbs_xts_ctx),
	.cra_alignmask = 7,
	.cra_type = &crypto_blkcipher_type,
	.cra_module = THIS_MODULE,
	.cra_blkcipher = {
	.min_keysize = 2 * AES_MIN_KEY_SIZE,
	.max_keysize = 2 * AES_MAX_KEY_SIZE,
	.ivsize = AES_BLOCK_SIZE,
	.setkey = aesbs_xts_set_key,
	.encrypt = aesbs_xts_encrypt,
	.decrypt = aesbs_xts_decrypt,
	},
	}, {
	.cra_name = "cbc(aes)",
	.cra_driver_name = "cbc-aes-neonbs",
	.cra_priority = 250,
	.cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER\|CRYPTO_ALG_ASYNC,
	.cra_blocksize = AES_BLOCK_SIZE,
	.cra_ctxsize = sizeof(struct async_helper_ctx),
	.cra_alignmask = 7,
	.cra_type = &crypto_ablkcipher_type,
	.cra_module = THIS_MODULE,
	.cra_init = ablk_init,
	.cra_exit = ablk_exit,
	.cra_ablkcipher = {
	.min_keysize = AES_MIN_KEY_SIZE,
	.max_keysize = AES_MAX_KEY_SIZE,
	.ivsize = AES_BLOCK_SIZE,
	.setkey = ablk_set_key,
	.encrypt = __ablk_encrypt,
	.decrypt = ablk_decrypt,
	}
	}, {
	.cra_name = "ctr(aes)",
	.cra_driver_name = "ctr-aes-neonbs",
	.cra_priority = 250,
	.cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER\|CRYPTO_ALG_ASYNC,
	.cra_blocksize = 1,
	.cra_ctxsize = sizeof(struct async_helper_ctx),
	.cra_alignmask = 7,
	.cra_type = &crypto_ablkcipher_type,
	.cra_module = THIS_MODULE,
	.cra_init = ablk_init,
	.cra_exit = ablk_exit,
	.cra_ablkcipher = {
	.min_keysize = AES_MIN_KEY_SIZE,
	.max_keysize = AES_MAX_KEY_SIZE,
	.ivsize = AES_BLOCK_SIZE,
	.setkey = ablk_set_key,
	.encrypt = ablk_encrypt,
	.decrypt = ablk_decrypt,
	}
	}, {
	.cra_name = "xts(aes)",
	.cra_driver_name = "xts-aes-neonbs",
	.cra_priority = 250,
	.cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER\|CRYPTO_ALG_ASYNC,
	.cra_blocksize = AES_BLOCK_SIZE,
	.cra_ctxsize = sizeof(struct async_helper_ctx),
	.cra_alignmask = 7,
	.cra_type = &crypto_ablkcipher_type,
	.cra_module = THIS_MODULE,
	.cra_init = ablk_init,
	.cra_exit = ablk_exit,
	.cra_ablkcipher = {
	.min_keysize = 2 * AES_MIN_KEY_SIZE,
	.max_keysize = 2 * AES_MAX_KEY_SIZE,
	.ivsize = AES_BLOCK_SIZE,
	.setkey = ablk_set_key,
	.encrypt = ablk_encrypt,
	.decrypt = ablk_decrypt,
	}
	} };

	static int __init aesbs_mod_init(void)
	{
	if (!cpu_has_neon())
	return -ENODEV;

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

	static void __exit aesbs_mod_exit(void)
	{
	crypto_unregister_algs(aesbs_algs, ARRAY_SIZE(aesbs_algs));
	}

	module_init(aesbs_mod_init);
	module_exit(aesbs_mod_exit);

	MODULE_DESCRIPTION("Bit sliced AES in CBC/CTR/XTS modes using NEON");
	MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
	MODULE_LICENSE("GPL");