arch/arm/crypto/aes-ce-glue.c - linux/torvalds/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * aes-ce-glue.c - wrapper code for ARMv8 AES
  *
  * Copyright (C) 2015 Linaro Ltd <ard.biesheuvel@linaro.org>
  */

 #include <asm/hwcap.h>
 #include <asm/neon.h>
 #include <asm/simd.h>
 #include <asm/unaligned.h>
 #include <crypto/aes.h>
 #include <crypto/ctr.h>
 #include <crypto/internal/simd.h>
 #include <crypto/internal/skcipher.h>
 #include <crypto/scatterwalk.h>
 #include <linux/cpufeature.h>
 #include <linux/module.h>
 #include <crypto/xts.h>

 MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS using ARMv8 Crypto Extensions");
 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
 MODULE_LICENSE("GPL v2");

 /* defined in aes-ce-core.S */
 asmlinkage u32 ce_aes_sub(u32 input);
 asmlinkage void ce_aes_invert(void *dst, void *src);

 asmlinkage void ce_aes_ecb_encrypt(u8 out[], u8 const in[], u32 const rk[],
 				   int rounds, int blocks);
 asmlinkage void ce_aes_ecb_decrypt(u8 out[], u8 const in[], u32 const rk[],
 				   int rounds, int blocks);

 asmlinkage void ce_aes_cbc_encrypt(u8 out[], u8 const in[], u32 const rk[],
 				   int rounds, int blocks, u8 iv[]);
 asmlinkage void ce_aes_cbc_decrypt(u8 out[], u8 const in[], u32 const rk[],
 				   int rounds, int blocks, u8 iv[]);
 asmlinkage void ce_aes_cbc_cts_encrypt(u8 out[], u8 const in[], u32 const rk[],
 				   int rounds, int bytes, u8 const iv[]);
 asmlinkage void ce_aes_cbc_cts_decrypt(u8 out[], u8 const in[], u32 const rk[],
 				   int rounds, int bytes, u8 const iv[]);

 asmlinkage void ce_aes_ctr_encrypt(u8 out[], u8 const in[], u32 const rk[],
 				   int rounds, int blocks, u8 ctr[]);

 asmlinkage void ce_aes_xts_encrypt(u8 out[], u8 const in[], u32 const rk1[],
 				   int rounds, int bytes, u8 iv[],
 				   u32 const rk2[], int first);
 asmlinkage void ce_aes_xts_decrypt(u8 out[], u8 const in[], u32 const rk1[],
 				   int rounds, int bytes, u8 iv[],
 				   u32 const rk2[], int first);

 struct aes_block {
 	u8 b[AES_BLOCK_SIZE];
 };

 static int num_rounds(struct crypto_aes_ctx *ctx)
 {
 	/*
 	 * # of rounds specified by AES:
 	 * 128 bit key		10 rounds
 	 * 192 bit key		12 rounds
 	 * 256 bit key		14 rounds
 	 * => n byte key	=> 6 + (n/4) rounds
 	 */
 	return 6 + ctx->key_length / 4;
 }

 static int ce_aes_expandkey(struct crypto_aes_ctx *ctx, const u8 *in_key,
 			    unsigned int key_len)
 {
 	/*
 	 * The AES key schedule round constants
 	 */
 	static u8 const rcon[] = {
 		0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36,
 	};

 	u32 kwords = key_len / sizeof(u32);
 	struct aes_block *key_enc, *key_dec;
 	int i, j;

 	if (key_len != AES_KEYSIZE_128 &&
 	    key_len != AES_KEYSIZE_192 &&
 	    key_len != AES_KEYSIZE_256)
 		return -EINVAL;

 	ctx->key_length = key_len;
 	for (i = 0; i < kwords; i++)
 		ctx->key_enc[i] = get_unaligned_le32(in_key + i * sizeof(u32));

 	kernel_neon_begin();
 	for (i = 0; i < sizeof(rcon); i++) {
 		u32 *rki = ctx->key_enc + (i * kwords);
 		u32 *rko = rki + kwords;

 		rko[0] = ror32(ce_aes_sub(rki[kwords - 1]), 8);
 		rko[0] = rko[0] ^ rki[0] ^ rcon[i];
 		rko[1] = rko[0] ^ rki[1];
 		rko[2] = rko[1] ^ rki[2];
 		rko[3] = rko[2] ^ rki[3];

 		if (key_len == AES_KEYSIZE_192) {
 			if (i >= 7)
 				break;
 			rko[4] = rko[3] ^ rki[4];
 			rko[5] = rko[4] ^ rki[5];
 		} else if (key_len == AES_KEYSIZE_256) {
 			if (i >= 6)
 				break;
 			rko[4] = ce_aes_sub(rko[3]) ^ rki[4];
 			rko[5] = rko[4] ^ rki[5];
 			rko[6] = rko[5] ^ rki[6];
 			rko[7] = rko[6] ^ rki[7];
 		}
 	}

 	/*
 	 * Generate the decryption keys for the Equivalent Inverse Cipher.
 	 * This involves reversing the order of the round keys, and applying
 	 * the Inverse Mix Columns transformation on all but the first and
 	 * the last one.
 	 */
 	key_enc = (struct aes_block *)ctx->key_enc;
 	key_dec = (struct aes_block *)ctx->key_dec;
 	j = num_rounds(ctx);

 	key_dec[0] = key_enc[j];
 	for (i = 1, j--; j > 0; i++, j--)
 		ce_aes_invert(key_dec + i, key_enc + j);
 	key_dec[i] = key_enc[0];

 	kernel_neon_end();
 	return 0;
 }

 static int ce_aes_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
 			 unsigned int key_len)
 {
 	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 	int ret;

 	ret = ce_aes_expandkey(ctx, in_key, key_len);
 	if (!ret)
 		return 0;

 	crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 	return -EINVAL;
 }

 struct crypto_aes_xts_ctx {
 	struct crypto_aes_ctx key1;
 	struct crypto_aes_ctx __aligned(8) key2;
 };

 static int xts_set_key(struct crypto_skcipher *tfm, const u8 *in_key,
 		       unsigned int key_len)
 {
 	struct crypto_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 	int ret;

 	ret = xts_verify_key(tfm, in_key, key_len);
 	if (ret)
 		return ret;

 	ret = ce_aes_expandkey(&ctx->key1, in_key, key_len / 2);
 	if (!ret)
 		ret = ce_aes_expandkey(&ctx->key2, &in_key[key_len / 2],
 				       key_len / 2);
 	if (!ret)
 		return 0;

 	crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 	return -EINVAL;
 }

 static int ecb_encrypt(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 	struct skcipher_walk walk;
 	unsigned int blocks;
 	int err;

 	err = skcipher_walk_virt(&walk, req, false);

 	while ((blocks = (walk.nbytes / AES_BLOCK_SIZE))) {
 		kernel_neon_begin();
 		ce_aes_ecb_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
 				   ctx->key_enc, num_rounds(ctx), blocks);
 		kernel_neon_end();
 		err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
 	}
 	return err;
 }

 static int ecb_decrypt(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 	struct skcipher_walk walk;
 	unsigned int blocks;
 	int err;

 	err = skcipher_walk_virt(&walk, req, false);

 	while ((blocks = (walk.nbytes / AES_BLOCK_SIZE))) {
 		kernel_neon_begin();
 		ce_aes_ecb_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
 				   ctx->key_dec, num_rounds(ctx), blocks);
 		kernel_neon_end();
 		err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
 	}
 	return err;
 }

 static int cbc_encrypt_walk(struct skcipher_request *req,
 			    struct skcipher_walk *walk)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 	unsigned int blocks;
 	int err = 0;

 	while ((blocks = (walk->nbytes / AES_BLOCK_SIZE))) {
 		kernel_neon_begin();
 		ce_aes_cbc_encrypt(walk->dst.virt.addr, walk->src.virt.addr,
 				   ctx->key_enc, num_rounds(ctx), blocks,
 				   walk->iv);
 		kernel_neon_end();
 		err = skcipher_walk_done(walk, walk->nbytes % AES_BLOCK_SIZE);
 	}
 	return err;
 }

 static int cbc_encrypt(struct skcipher_request *req)
 {
 	struct skcipher_walk walk;
 	int err;

 	err = skcipher_walk_virt(&walk, req, false);
 	if (err)
 		return err;
 	return cbc_encrypt_walk(req, &walk);
 }

 static int cbc_decrypt_walk(struct skcipher_request *req,
 			    struct skcipher_walk *walk)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 	unsigned int blocks;
 	int err = 0;

 	while ((blocks = (walk->nbytes / AES_BLOCK_SIZE))) {
 		kernel_neon_begin();
 		ce_aes_cbc_decrypt(walk->dst.virt.addr, walk->src.virt.addr,
 				   ctx->key_dec, num_rounds(ctx), blocks,
 				   walk->iv);
 		kernel_neon_end();
 		err = skcipher_walk_done(walk, walk->nbytes % AES_BLOCK_SIZE);
 	}
 	return err;
 }

 static int cbc_decrypt(struct skcipher_request *req)
 {
 	struct skcipher_walk walk;
 	int err;

 	err = skcipher_walk_virt(&walk, req, false);
 	if (err)
 		return err;
 	return cbc_decrypt_walk(req, &walk);
 }

 static int cts_cbc_encrypt(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 	int cbc_blocks = DIV_ROUND_UP(req->cryptlen, AES_BLOCK_SIZE) - 2;
 	struct scatterlist *src = req->src, *dst = req->dst;
 	struct scatterlist sg_src[2], sg_dst[2];
 	struct skcipher_request subreq;
 	struct skcipher_walk walk;
 	int err;

 	skcipher_request_set_tfm(&subreq, tfm);
 	skcipher_request_set_callback(&subreq, skcipher_request_flags(req),
 				      NULL, NULL);

 	if (req->cryptlen <= AES_BLOCK_SIZE) {
 		if (req->cryptlen < AES_BLOCK_SIZE)
 			return -EINVAL;
 		cbc_blocks = 1;
 	}

 	if (cbc_blocks > 0) {
 		skcipher_request_set_crypt(&subreq, req->src, req->dst,
 					   cbc_blocks * AES_BLOCK_SIZE,
 					   req->iv);

 		err = skcipher_walk_virt(&walk, &subreq, false) ?:
 		      cbc_encrypt_walk(&subreq, &walk);
 		if (err)
 			return err;

 		if (req->cryptlen == AES_BLOCK_SIZE)
 			return 0;

 		dst = src = scatterwalk_ffwd(sg_src, req->src, subreq.cryptlen);
 		if (req->dst != req->src)
 			dst = scatterwalk_ffwd(sg_dst, req->dst,
 					       subreq.cryptlen);
 	}

 	/* handle ciphertext stealing */
 	skcipher_request_set_crypt(&subreq, src, dst,
 				   req->cryptlen - cbc_blocks * AES_BLOCK_SIZE,
 				   req->iv);

 	err = skcipher_walk_virt(&walk, &subreq, false);
 	if (err)
 		return err;

 	kernel_neon_begin();
 	ce_aes_cbc_cts_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
 			       ctx->key_enc, num_rounds(ctx), walk.nbytes,
 			       walk.iv);
 	kernel_neon_end();

 	return skcipher_walk_done(&walk, 0);
 }

 static int cts_cbc_decrypt(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 	int cbc_blocks = DIV_ROUND_UP(req->cryptlen, AES_BLOCK_SIZE) - 2;
 	struct scatterlist *src = req->src, *dst = req->dst;
 	struct scatterlist sg_src[2], sg_dst[2];
 	struct skcipher_request subreq;
 	struct skcipher_walk walk;
 	int err;

 	skcipher_request_set_tfm(&subreq, tfm);
 	skcipher_request_set_callback(&subreq, skcipher_request_flags(req),
 				      NULL, NULL);

 	if (req->cryptlen <= AES_BLOCK_SIZE) {
 		if (req->cryptlen < AES_BLOCK_SIZE)
 			return -EINVAL;
 		cbc_blocks = 1;
 	}

 	if (cbc_blocks > 0) {
 		skcipher_request_set_crypt(&subreq, req->src, req->dst,
 					   cbc_blocks * AES_BLOCK_SIZE,
 					   req->iv);

 		err = skcipher_walk_virt(&walk, &subreq, false) ?:
 		      cbc_decrypt_walk(&subreq, &walk);
 		if (err)
 			return err;

 		if (req->cryptlen == AES_BLOCK_SIZE)
 			return 0;

 		dst = src = scatterwalk_ffwd(sg_src, req->src, subreq.cryptlen);
 		if (req->dst != req->src)
 			dst = scatterwalk_ffwd(sg_dst, req->dst,
 					       subreq.cryptlen);
 	}

 	/* handle ciphertext stealing */
 	skcipher_request_set_crypt(&subreq, src, dst,
 				   req->cryptlen - cbc_blocks * AES_BLOCK_SIZE,
 				   req->iv);

 	err = skcipher_walk_virt(&walk, &subreq, false);
 	if (err)
 		return err;

 	kernel_neon_begin();
 	ce_aes_cbc_cts_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
 			       ctx->key_dec, num_rounds(ctx), walk.nbytes,
 			       walk.iv);
 	kernel_neon_end();

 	return skcipher_walk_done(&walk, 0);
 }

 static int ctr_encrypt(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 	struct skcipher_walk walk;
 	int err, blocks;

 	err = skcipher_walk_virt(&walk, req, false);

 	while ((blocks = (walk.nbytes / AES_BLOCK_SIZE))) {
 		kernel_neon_begin();
 		ce_aes_ctr_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
 				   ctx->key_enc, num_rounds(ctx), blocks,
 				   walk.iv);
 		kernel_neon_end();
 		err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
 	}
 	if (walk.nbytes) {
 		u8 __aligned(8) tail[AES_BLOCK_SIZE];
 		unsigned int nbytes = walk.nbytes;
 		u8 *tdst = walk.dst.virt.addr;
 		u8 *tsrc = walk.src.virt.addr;

 		/*
 		 * Tell aes_ctr_encrypt() to process a tail block.
 		 */
 		blocks = -1;

 		kernel_neon_begin();
 		ce_aes_ctr_encrypt(tail, NULL, ctx->key_enc, num_rounds(ctx),
 				   blocks, walk.iv);
 		kernel_neon_end();
 		crypto_xor_cpy(tdst, tsrc, tail, nbytes);
 		err = skcipher_walk_done(&walk, 0);
 	}
 	return err;
 }

 static void ctr_encrypt_one(struct crypto_skcipher *tfm, const u8 *src, u8 *dst)
 {
 	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 	unsigned long flags;

 	/*
 	 * Temporarily disable interrupts to avoid races where
 	 * cachelines are evicted when the CPU is interrupted
 	 * to do something else.
 	 */
 	local_irq_save(flags);
 	aes_encrypt(ctx, dst, src);
 	local_irq_restore(flags);
 }

 static int ctr_encrypt_sync(struct skcipher_request *req)
 {
 	if (!crypto_simd_usable())
 		return crypto_ctr_encrypt_walk(req, ctr_encrypt_one);

 	return ctr_encrypt(req);
 }

 static int xts_encrypt(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct crypto_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 	int err, first, rounds = num_rounds(&ctx->key1);
 	int tail = req->cryptlen % AES_BLOCK_SIZE;
 	struct scatterlist sg_src[2], sg_dst[2];
 	struct skcipher_request subreq;
 	struct scatterlist *src, *dst;
 	struct skcipher_walk walk;

 	if (req->cryptlen < AES_BLOCK_SIZE)
 		return -EINVAL;

 	err = skcipher_walk_virt(&walk, req, false);

 	if (unlikely(tail > 0 && walk.nbytes < walk.total)) {
 		int xts_blocks = DIV_ROUND_UP(req->cryptlen,
 					      AES_BLOCK_SIZE) - 2;

 		skcipher_walk_abort(&walk);

 		skcipher_request_set_tfm(&subreq, tfm);
 		skcipher_request_set_callback(&subreq,
 					      skcipher_request_flags(req),
 					      NULL, NULL);
 		skcipher_request_set_crypt(&subreq, req->src, req->dst,
 					   xts_blocks * AES_BLOCK_SIZE,
 					   req->iv);
 		req = &subreq;
 		err = skcipher_walk_virt(&walk, req, false);
 	} else {
 		tail = 0;
 	}

 	for (first = 1; walk.nbytes >= AES_BLOCK_SIZE; first = 0) {
 		int nbytes = walk.nbytes;

 		if (walk.nbytes < walk.total)
 			nbytes &= ~(AES_BLOCK_SIZE - 1);

 		kernel_neon_begin();
 		ce_aes_xts_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
 				   ctx->key1.key_enc, rounds, nbytes, walk.iv,
 				   ctx->key2.key_enc, first);
 		kernel_neon_end();
 		err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
 	}

 	if (err || likely(!tail))
 		return err;

 	dst = src = scatterwalk_ffwd(sg_src, req->src, req->cryptlen);
 	if (req->dst != req->src)
 		dst = scatterwalk_ffwd(sg_dst, req->dst, req->cryptlen);

 	skcipher_request_set_crypt(req, src, dst, AES_BLOCK_SIZE + tail,
 				   req->iv);

 	err = skcipher_walk_virt(&walk, req, false);
 	if (err)
 		return err;

 	kernel_neon_begin();
 	ce_aes_xts_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
 			   ctx->key1.key_enc, rounds, walk.nbytes, walk.iv,
 			   ctx->key2.key_enc, first);
 	kernel_neon_end();

 	return skcipher_walk_done(&walk, 0);
 }

 static int xts_decrypt(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct crypto_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 	int err, first, rounds = num_rounds(&ctx->key1);
 	int tail = req->cryptlen % AES_BLOCK_SIZE;
 	struct scatterlist sg_src[2], sg_dst[2];
 	struct skcipher_request subreq;
 	struct scatterlist *src, *dst;
 	struct skcipher_walk walk;

 	if (req->cryptlen < AES_BLOCK_SIZE)
 		return -EINVAL;

 	err = skcipher_walk_virt(&walk, req, false);

 	if (unlikely(tail > 0 && walk.nbytes < walk.total)) {
 		int xts_blocks = DIV_ROUND_UP(req->cryptlen,
 					      AES_BLOCK_SIZE) - 2;

 		skcipher_walk_abort(&walk);

 		skcipher_request_set_tfm(&subreq, tfm);
 		skcipher_request_set_callback(&subreq,
 					      skcipher_request_flags(req),
 					      NULL, NULL);
 		skcipher_request_set_crypt(&subreq, req->src, req->dst,
 					   xts_blocks * AES_BLOCK_SIZE,
 					   req->iv);
 		req = &subreq;
 		err = skcipher_walk_virt(&walk, req, false);
 	} else {
 		tail = 0;
 	}

 	for (first = 1; walk.nbytes >= AES_BLOCK_SIZE; first = 0) {
 		int nbytes = walk.nbytes;

 		if (walk.nbytes < walk.total)
 			nbytes &= ~(AES_BLOCK_SIZE - 1);

 		kernel_neon_begin();
 		ce_aes_xts_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
 				   ctx->key1.key_dec, rounds, nbytes, walk.iv,
 				   ctx->key2.key_enc, first);
 		kernel_neon_end();
 		err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
 	}

 	if (err || likely(!tail))
 		return err;

 	dst = src = scatterwalk_ffwd(sg_src, req->src, req->cryptlen);
 	if (req->dst != req->src)
 		dst = scatterwalk_ffwd(sg_dst, req->dst, req->cryptlen);

 	skcipher_request_set_crypt(req, src, dst, AES_BLOCK_SIZE + tail,
 				   req->iv);

 	err = skcipher_walk_virt(&walk, req, false);
 	if (err)
 		return err;

 	kernel_neon_begin();
 	ce_aes_xts_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
 			   ctx->key1.key_dec, rounds, walk.nbytes, walk.iv,
 			   ctx->key2.key_enc, first);
 	kernel_neon_end();

 	return skcipher_walk_done(&walk, 0);
 }

 static struct skcipher_alg aes_algs[] = { {
 	.base.cra_name		= "__ecb(aes)",
 	.base.cra_driver_name	= "__ecb-aes-ce",
 	.base.cra_priority	= 300,
 	.base.cra_flags		= CRYPTO_ALG_INTERNAL,
 	.base.cra_blocksize	= AES_BLOCK_SIZE,
 	.base.cra_ctxsize	= sizeof(struct crypto_aes_ctx),
 	.base.cra_module	= THIS_MODULE,

 	.min_keysize		= AES_MIN_KEY_SIZE,
 	.max_keysize		= AES_MAX_KEY_SIZE,
 	.setkey			= ce_aes_setkey,
 	.encrypt		= ecb_encrypt,
 	.decrypt		= ecb_decrypt,
 }, {
 	.base.cra_name		= "__cbc(aes)",
 	.base.cra_driver_name	= "__cbc-aes-ce",
 	.base.cra_priority	= 300,
 	.base.cra_flags		= CRYPTO_ALG_INTERNAL,
 	.base.cra_blocksize	= AES_BLOCK_SIZE,
 	.base.cra_ctxsize	= sizeof(struct crypto_aes_ctx),
 	.base.cra_module	= THIS_MODULE,

 	.min_keysize		= AES_MIN_KEY_SIZE,
 	.max_keysize		= AES_MAX_KEY_SIZE,
 	.ivsize			= AES_BLOCK_SIZE,
 	.setkey			= ce_aes_setkey,
 	.encrypt		= cbc_encrypt,
 	.decrypt		= cbc_decrypt,
 }, {
 	.base.cra_name		= "__cts(cbc(aes))",
 	.base.cra_driver_name	= "__cts-cbc-aes-ce",
 	.base.cra_priority	= 300,
 	.base.cra_flags		= CRYPTO_ALG_INTERNAL,
 	.base.cra_blocksize	= AES_BLOCK_SIZE,
 	.base.cra_ctxsize	= sizeof(struct crypto_aes_ctx),
 	.base.cra_module	= THIS_MODULE,

 	.min_keysize		= AES_MIN_KEY_SIZE,
 	.max_keysize		= AES_MAX_KEY_SIZE,
 	.ivsize			= AES_BLOCK_SIZE,
 	.walksize		= 2 * AES_BLOCK_SIZE,
 	.setkey			= ce_aes_setkey,
 	.encrypt		= cts_cbc_encrypt,
 	.decrypt		= cts_cbc_decrypt,
 }, {
 	.base.cra_name		= "__ctr(aes)",
 	.base.cra_driver_name	= "__ctr-aes-ce",
 	.base.cra_priority	= 300,
 	.base.cra_flags		= CRYPTO_ALG_INTERNAL,
 	.base.cra_blocksize	= 1,
 	.base.cra_ctxsize	= sizeof(struct crypto_aes_ctx),
 	.base.cra_module	= THIS_MODULE,

 	.min_keysize		= AES_MIN_KEY_SIZE,
 	.max_keysize		= AES_MAX_KEY_SIZE,
 	.ivsize			= AES_BLOCK_SIZE,
 	.chunksize		= AES_BLOCK_SIZE,
 	.setkey			= ce_aes_setkey,
 	.encrypt		= ctr_encrypt,
 	.decrypt		= ctr_encrypt,
 }, {
 	.base.cra_name		= "ctr(aes)",
 	.base.cra_driver_name	= "ctr-aes-ce-sync",
 	.base.cra_priority	= 300 - 1,
 	.base.cra_blocksize	= 1,
 	.base.cra_ctxsize	= sizeof(struct crypto_aes_ctx),
 	.base.cra_module	= THIS_MODULE,

 	.min_keysize		= AES_MIN_KEY_SIZE,
 	.max_keysize		= AES_MAX_KEY_SIZE,
 	.ivsize			= AES_BLOCK_SIZE,
 	.chunksize		= AES_BLOCK_SIZE,
 	.setkey			= ce_aes_setkey,
 	.encrypt		= ctr_encrypt_sync,
 	.decrypt		= ctr_encrypt_sync,
 }, {
 	.base.cra_name		= "__xts(aes)",
 	.base.cra_driver_name	= "__xts-aes-ce",
 	.base.cra_priority	= 300,
 	.base.cra_flags		= CRYPTO_ALG_INTERNAL,
 	.base.cra_blocksize	= AES_BLOCK_SIZE,
 	.base.cra_ctxsize	= sizeof(struct crypto_aes_xts_ctx),
 	.base.cra_module	= THIS_MODULE,

 	.min_keysize		= 2 * AES_MIN_KEY_SIZE,
 	.max_keysize		= 2 * AES_MAX_KEY_SIZE,
 	.ivsize			= AES_BLOCK_SIZE,
 	.walksize		= 2 * AES_BLOCK_SIZE,
 	.setkey			= xts_set_key,
 	.encrypt		= xts_encrypt,
 	.decrypt		= xts_decrypt,
 } };

 static struct simd_skcipher_alg *aes_simd_algs[ARRAY_SIZE(aes_algs)];

 static void aes_exit(void)
 {
 	int i;

 	for (i = 0; i < ARRAY_SIZE(aes_simd_algs) && aes_simd_algs[i]; i++)
 		simd_skcipher_free(aes_simd_algs[i]);

 	crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
 }

 static int __init aes_init(void)
 {
 	struct simd_skcipher_alg *simd;
 	const char *basename;
 	const char *algname;
 	const char *drvname;
 	int err;
 	int i;

 	err = crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
 	if (err)
 		return err;

 	for (i = 0; i < ARRAY_SIZE(aes_algs); i++) {
 		if (!(aes_algs[i].base.cra_flags & CRYPTO_ALG_INTERNAL))
 			continue;

 		algname = aes_algs[i].base.cra_name + 2;
 		drvname = aes_algs[i].base.cra_driver_name + 2;
 		basename = aes_algs[i].base.cra_driver_name;
 		simd = simd_skcipher_create_compat(algname, drvname, basename);
 		err = PTR_ERR(simd);
 		if (IS_ERR(simd))
 			goto unregister_simds;

 		aes_simd_algs[i] = simd;
 	}

 	return 0;

 unregister_simds:
 	aes_exit();
 	return err;
 }

 module_cpu_feature_match(AES, aes_init);
 module_exit(aes_exit);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* aes-ce-glue.c - wrapper code for ARMv8 AES
	*
	* Copyright (C) 2015 Linaro Ltd <ard.biesheuvel@linaro.org>
	*/

	#include <asm/hwcap.h>
	#include <asm/neon.h>
	#include <asm/simd.h>
	#include <asm/unaligned.h>
	#include <crypto/aes.h>
	#include <crypto/ctr.h>
	#include <crypto/internal/simd.h>
	#include <crypto/internal/skcipher.h>
	#include <crypto/scatterwalk.h>
	#include <linux/cpufeature.h>
	#include <linux/module.h>
	#include <crypto/xts.h>

	MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS using ARMv8 Crypto Extensions");
	MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
	MODULE_LICENSE("GPL v2");

	/* defined in aes-ce-core.S */
	asmlinkage u32 ce_aes_sub(u32 input);
	asmlinkage void ce_aes_invert(void dst, void src);

	asmlinkage void ce_aes_ecb_encrypt(u8 out[], u8 const in[], u32 const rk[],
	int rounds, int blocks);
	asmlinkage void ce_aes_ecb_decrypt(u8 out[], u8 const in[], u32 const rk[],
	int rounds, int blocks);

	asmlinkage void ce_aes_cbc_encrypt(u8 out[], u8 const in[], u32 const rk[],
	int rounds, int blocks, u8 iv[]);
	asmlinkage void ce_aes_cbc_decrypt(u8 out[], u8 const in[], u32 const rk[],
	int rounds, int blocks, u8 iv[]);
	asmlinkage void ce_aes_cbc_cts_encrypt(u8 out[], u8 const in[], u32 const rk[],
	int rounds, int bytes, u8 const iv[]);
	asmlinkage void ce_aes_cbc_cts_decrypt(u8 out[], u8 const in[], u32 const rk[],
	int rounds, int bytes, u8 const iv[]);

	asmlinkage void ce_aes_ctr_encrypt(u8 out[], u8 const in[], u32 const rk[],
	int rounds, int blocks, u8 ctr[]);

	asmlinkage void ce_aes_xts_encrypt(u8 out[], u8 const in[], u32 const rk1[],
	int rounds, int bytes, u8 iv[],
	u32 const rk2[], int first);
	asmlinkage void ce_aes_xts_decrypt(u8 out[], u8 const in[], u32 const rk1[],
	int rounds, int bytes, u8 iv[],
	u32 const rk2[], int first);

	struct aes_block {
	u8 b[AES_BLOCK_SIZE];
	};

	static int num_rounds(struct crypto_aes_ctx *ctx)
	{
	/*
	* # of rounds specified by AES:
	* 128 bit key 10 rounds
	* 192 bit key 12 rounds
	* 256 bit key 14 rounds
	* => n byte key => 6 + (n/4) rounds
	*/
	return 6 + ctx->key_length / 4;
	}

	static int ce_aes_expandkey(struct crypto_aes_ctx ctx, const u8 in_key,
	unsigned int key_len)
	{
	/*
	* The AES key schedule round constants
	*/
	static u8 const rcon[] = {
	0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36,
	};

	u32 kwords = key_len / sizeof(u32);
	struct aes_block key_enc, key_dec;
	int i, j;

	if (key_len != AES_KEYSIZE_128 &&
	key_len != AES_KEYSIZE_192 &&
	key_len != AES_KEYSIZE_256)
	return -EINVAL;

	ctx->key_length = key_len;
	for (i = 0; i < kwords; i++)
	ctx->key_enc[i] = get_unaligned_le32(in_key + i * sizeof(u32));

	kernel_neon_begin();
	for (i = 0; i < sizeof(rcon); i++) {
	u32 rki = ctx->key_enc + (i kwords);
	u32 *rko = rki + kwords;

	rko[0] = ror32(ce_aes_sub(rki[kwords - 1]), 8);
	rko[0] = rko[0] ^ rki[0] ^ rcon[i];
	rko[1] = rko[0] ^ rki[1];
	rko[2] = rko[1] ^ rki[2];
	rko[3] = rko[2] ^ rki[3];

	if (key_len == AES_KEYSIZE_192) {
	if (i >= 7)
	break;
	rko[4] = rko[3] ^ rki[4];
	rko[5] = rko[4] ^ rki[5];
	} else if (key_len == AES_KEYSIZE_256) {
	if (i >= 6)
	break;
	rko[4] = ce_aes_sub(rko[3]) ^ rki[4];
	rko[5] = rko[4] ^ rki[5];
	rko[6] = rko[5] ^ rki[6];
	rko[7] = rko[6] ^ rki[7];
	}
	}

	/*
	* Generate the decryption keys for the Equivalent Inverse Cipher.
	* This involves reversing the order of the round keys, and applying
	* the Inverse Mix Columns transformation on all but the first and
	* the last one.
	*/
	key_enc = (struct aes_block *)ctx->key_enc;
	key_dec = (struct aes_block *)ctx->key_dec;
	j = num_rounds(ctx);

	key_dec[0] = key_enc[j];
	for (i = 1, j--; j > 0; i++, j--)
	ce_aes_invert(key_dec + i, key_enc + j);
	key_dec[i] = key_enc[0];

	kernel_neon_end();
	return 0;
	}

	static int ce_aes_setkey(struct crypto_skcipher tfm, const u8 in_key,
	unsigned int key_len)
	{
	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
	int ret;

	ret = ce_aes_expandkey(ctx, in_key, key_len);
	if (!ret)
	return 0;

	crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
	return -EINVAL;
	}

	struct crypto_aes_xts_ctx {
	struct crypto_aes_ctx key1;
	struct crypto_aes_ctx __aligned(8) key2;
	};

	static int xts_set_key(struct crypto_skcipher tfm, const u8 in_key,
	unsigned int key_len)
	{
	struct crypto_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
	int ret;

	ret = xts_verify_key(tfm, in_key, key_len);
	if (ret)
	return ret;

	ret = ce_aes_expandkey(&ctx->key1, in_key, key_len / 2);
	if (!ret)
	ret = ce_aes_expandkey(&ctx->key2, &in_key[key_len / 2],
	key_len / 2);
	if (!ret)
	return 0;

	crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
	return -EINVAL;
	}

	static int ecb_encrypt(struct skcipher_request *req)
	{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct skcipher_walk walk;
	unsigned int blocks;
	int err;

	err = skcipher_walk_virt(&walk, req, false);

	while ((blocks = (walk.nbytes / AES_BLOCK_SIZE))) {
	kernel_neon_begin();
	ce_aes_ecb_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
	ctx->key_enc, num_rounds(ctx), blocks);
	kernel_neon_end();
	err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
	}
	return err;
	}

	static int ecb_decrypt(struct skcipher_request *req)
	{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct skcipher_walk walk;
	unsigned int blocks;
	int err;

	err = skcipher_walk_virt(&walk, req, false);

	while ((blocks = (walk.nbytes / AES_BLOCK_SIZE))) {
	kernel_neon_begin();
	ce_aes_ecb_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
	ctx->key_dec, num_rounds(ctx), blocks);
	kernel_neon_end();
	err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
	}
	return err;
	}

	static int cbc_encrypt_walk(struct skcipher_request *req,
	struct skcipher_walk *walk)
	{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
	unsigned int blocks;
	int err = 0;

	while ((blocks = (walk->nbytes / AES_BLOCK_SIZE))) {
	kernel_neon_begin();
	ce_aes_cbc_encrypt(walk->dst.virt.addr, walk->src.virt.addr,
	ctx->key_enc, num_rounds(ctx), blocks,
	walk->iv);
	kernel_neon_end();
	err = skcipher_walk_done(walk, walk->nbytes % AES_BLOCK_SIZE);
	}
	return err;
	}

	static int cbc_encrypt(struct skcipher_request *req)
	{
	struct skcipher_walk walk;
	int err;

	err = skcipher_walk_virt(&walk, req, false);
	if (err)
	return err;
	return cbc_encrypt_walk(req, &walk);
	}

	static int cbc_decrypt_walk(struct skcipher_request *req,
	struct skcipher_walk *walk)
	{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
	unsigned int blocks;
	int err = 0;

	while ((blocks = (walk->nbytes / AES_BLOCK_SIZE))) {
	kernel_neon_begin();
	ce_aes_cbc_decrypt(walk->dst.virt.addr, walk->src.virt.addr,
	ctx->key_dec, num_rounds(ctx), blocks,
	walk->iv);
	kernel_neon_end();
	err = skcipher_walk_done(walk, walk->nbytes % AES_BLOCK_SIZE);
	}
	return err;
	}

	static int cbc_decrypt(struct skcipher_request *req)
	{
	struct skcipher_walk walk;
	int err;

	err = skcipher_walk_virt(&walk, req, false);
	if (err)
	return err;
	return cbc_decrypt_walk(req, &walk);
	}

	static int cts_cbc_encrypt(struct skcipher_request *req)
	{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
	int cbc_blocks = DIV_ROUND_UP(req->cryptlen, AES_BLOCK_SIZE) - 2;
	struct scatterlist src = req->src, dst = req->dst;
	struct scatterlist sg_src[2], sg_dst[2];
	struct skcipher_request subreq;
	struct skcipher_walk walk;
	int err;

	skcipher_request_set_tfm(&subreq, tfm);
	skcipher_request_set_callback(&subreq, skcipher_request_flags(req),
	NULL, NULL);

	if (req->cryptlen <= AES_BLOCK_SIZE) {
	if (req->cryptlen < AES_BLOCK_SIZE)
	return -EINVAL;
	cbc_blocks = 1;
	}

	if (cbc_blocks > 0) {
	skcipher_request_set_crypt(&subreq, req->src, req->dst,
	cbc_blocks * AES_BLOCK_SIZE,
	req->iv);

	err = skcipher_walk_virt(&walk, &subreq, false) ?:
	cbc_encrypt_walk(&subreq, &walk);
	if (err)
	return err;

	if (req->cryptlen == AES_BLOCK_SIZE)
	return 0;

	dst = src = scatterwalk_ffwd(sg_src, req->src, subreq.cryptlen);
	if (req->dst != req->src)
	dst = scatterwalk_ffwd(sg_dst, req->dst,
	subreq.cryptlen);
	}

	/* handle ciphertext stealing */
	skcipher_request_set_crypt(&subreq, src, dst,
	req->cryptlen - cbc_blocks * AES_BLOCK_SIZE,
	req->iv);

	err = skcipher_walk_virt(&walk, &subreq, false);
	if (err)
	return err;

	kernel_neon_begin();
	ce_aes_cbc_cts_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
	ctx->key_enc, num_rounds(ctx), walk.nbytes,
	walk.iv);
	kernel_neon_end();

	return skcipher_walk_done(&walk, 0);
	}

	static int cts_cbc_decrypt(struct skcipher_request *req)
	{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
	int cbc_blocks = DIV_ROUND_UP(req->cryptlen, AES_BLOCK_SIZE) - 2;
	struct scatterlist src = req->src, dst = req->dst;
	struct scatterlist sg_src[2], sg_dst[2];
	struct skcipher_request subreq;
	struct skcipher_walk walk;
	int err;

	skcipher_request_set_tfm(&subreq, tfm);
	skcipher_request_set_callback(&subreq, skcipher_request_flags(req),
	NULL, NULL);

	if (req->cryptlen <= AES_BLOCK_SIZE) {
	if (req->cryptlen < AES_BLOCK_SIZE)
	return -EINVAL;
	cbc_blocks = 1;
	}

	if (cbc_blocks > 0) {
	skcipher_request_set_crypt(&subreq, req->src, req->dst,
	cbc_blocks * AES_BLOCK_SIZE,
	req->iv);

	err = skcipher_walk_virt(&walk, &subreq, false) ?:
	cbc_decrypt_walk(&subreq, &walk);
	if (err)
	return err;

	if (req->cryptlen == AES_BLOCK_SIZE)
	return 0;

	dst = src = scatterwalk_ffwd(sg_src, req->src, subreq.cryptlen);
	if (req->dst != req->src)
	dst = scatterwalk_ffwd(sg_dst, req->dst,
	subreq.cryptlen);
	}

	/* handle ciphertext stealing */
	skcipher_request_set_crypt(&subreq, src, dst,
	req->cryptlen - cbc_blocks * AES_BLOCK_SIZE,
	req->iv);

	err = skcipher_walk_virt(&walk, &subreq, false);
	if (err)
	return err;

	kernel_neon_begin();
	ce_aes_cbc_cts_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
	ctx->key_dec, num_rounds(ctx), walk.nbytes,
	walk.iv);
	kernel_neon_end();

	return skcipher_walk_done(&walk, 0);
	}

	static int ctr_encrypt(struct skcipher_request *req)
	{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct skcipher_walk walk;
	int err, blocks;

	err = skcipher_walk_virt(&walk, req, false);

	while ((blocks = (walk.nbytes / AES_BLOCK_SIZE))) {
	kernel_neon_begin();
	ce_aes_ctr_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
	ctx->key_enc, num_rounds(ctx), blocks,
	walk.iv);
	kernel_neon_end();
	err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
	}
	if (walk.nbytes) {
	u8 __aligned(8) tail[AES_BLOCK_SIZE];
	unsigned int nbytes = walk.nbytes;
	u8 *tdst = walk.dst.virt.addr;
	u8 *tsrc = walk.src.virt.addr;

	/*
	* Tell aes_ctr_encrypt() to process a tail block.
	*/
	blocks = -1;

	kernel_neon_begin();
	ce_aes_ctr_encrypt(tail, NULL, ctx->key_enc, num_rounds(ctx),
	blocks, walk.iv);
	kernel_neon_end();
	crypto_xor_cpy(tdst, tsrc, tail, nbytes);
	err = skcipher_walk_done(&walk, 0);
	}
	return err;
	}

	static void ctr_encrypt_one(struct crypto_skcipher tfm, const u8 src, u8 *dst)
	{
	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
	unsigned long flags;

	/*
	* Temporarily disable interrupts to avoid races where
	* cachelines are evicted when the CPU is interrupted
	* to do something else.
	*/
	local_irq_save(flags);
	aes_encrypt(ctx, dst, src);
	local_irq_restore(flags);
	}

	static int ctr_encrypt_sync(struct skcipher_request *req)
	{
	if (!crypto_simd_usable())
	return crypto_ctr_encrypt_walk(req, ctr_encrypt_one);

	return ctr_encrypt(req);
	}

	static int xts_encrypt(struct skcipher_request *req)
	{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct crypto_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
	int err, first, rounds = num_rounds(&ctx->key1);
	int tail = req->cryptlen % AES_BLOCK_SIZE;
	struct scatterlist sg_src[2], sg_dst[2];
	struct skcipher_request subreq;
	struct scatterlist src, dst;
	struct skcipher_walk walk;

	if (req->cryptlen < AES_BLOCK_SIZE)
	return -EINVAL;

	err = skcipher_walk_virt(&walk, req, false);

	if (unlikely(tail > 0 && walk.nbytes < walk.total)) {
	int xts_blocks = DIV_ROUND_UP(req->cryptlen,
	AES_BLOCK_SIZE) - 2;

	skcipher_walk_abort(&walk);

	skcipher_request_set_tfm(&subreq, tfm);
	skcipher_request_set_callback(&subreq,
	skcipher_request_flags(req),
	NULL, NULL);
	skcipher_request_set_crypt(&subreq, req->src, req->dst,
	xts_blocks * AES_BLOCK_SIZE,
	req->iv);
	req = &subreq;
	err = skcipher_walk_virt(&walk, req, false);
	} else {
	tail = 0;
	}

	for (first = 1; walk.nbytes >= AES_BLOCK_SIZE; first = 0) {
	int nbytes = walk.nbytes;

	if (walk.nbytes < walk.total)
	nbytes &= ~(AES_BLOCK_SIZE - 1);

	kernel_neon_begin();
	ce_aes_xts_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
	ctx->key1.key_enc, rounds, nbytes, walk.iv,
	ctx->key2.key_enc, first);
	kernel_neon_end();
	err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
	}

	if (err \|\| likely(!tail))
	return err;

	dst = src = scatterwalk_ffwd(sg_src, req->src, req->cryptlen);
	if (req->dst != req->src)
	dst = scatterwalk_ffwd(sg_dst, req->dst, req->cryptlen);

	skcipher_request_set_crypt(req, src, dst, AES_BLOCK_SIZE + tail,
	req->iv);

	err = skcipher_walk_virt(&walk, req, false);
	if (err)
	return err;

	kernel_neon_begin();
	ce_aes_xts_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
	ctx->key1.key_enc, rounds, walk.nbytes, walk.iv,
	ctx->key2.key_enc, first);
	kernel_neon_end();

	return skcipher_walk_done(&walk, 0);
	}

	static int xts_decrypt(struct skcipher_request *req)
	{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct crypto_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
	int err, first, rounds = num_rounds(&ctx->key1);
	int tail = req->cryptlen % AES_BLOCK_SIZE;
	struct scatterlist sg_src[2], sg_dst[2];
	struct skcipher_request subreq;
	struct scatterlist src, dst;
	struct skcipher_walk walk;

	if (req->cryptlen < AES_BLOCK_SIZE)
	return -EINVAL;

	err = skcipher_walk_virt(&walk, req, false);

	if (unlikely(tail > 0 && walk.nbytes < walk.total)) {
	int xts_blocks = DIV_ROUND_UP(req->cryptlen,
	AES_BLOCK_SIZE) - 2;

	skcipher_walk_abort(&walk);

	skcipher_request_set_tfm(&subreq, tfm);
	skcipher_request_set_callback(&subreq,
	skcipher_request_flags(req),
	NULL, NULL);
	skcipher_request_set_crypt(&subreq, req->src, req->dst,
	xts_blocks * AES_BLOCK_SIZE,
	req->iv);
	req = &subreq;
	err = skcipher_walk_virt(&walk, req, false);
	} else {
	tail = 0;
	}

	for (first = 1; walk.nbytes >= AES_BLOCK_SIZE; first = 0) {
	int nbytes = walk.nbytes;

	if (walk.nbytes < walk.total)
	nbytes &= ~(AES_BLOCK_SIZE - 1);

	kernel_neon_begin();
	ce_aes_xts_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
	ctx->key1.key_dec, rounds, nbytes, walk.iv,
	ctx->key2.key_enc, first);
	kernel_neon_end();
	err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
	}

	if (err \|\| likely(!tail))
	return err;

	dst = src = scatterwalk_ffwd(sg_src, req->src, req->cryptlen);
	if (req->dst != req->src)
	dst = scatterwalk_ffwd(sg_dst, req->dst, req->cryptlen);

	skcipher_request_set_crypt(req, src, dst, AES_BLOCK_SIZE + tail,
	req->iv);

	err = skcipher_walk_virt(&walk, req, false);
	if (err)
	return err;

	kernel_neon_begin();
	ce_aes_xts_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
	ctx->key1.key_dec, rounds, walk.nbytes, walk.iv,
	ctx->key2.key_enc, first);
	kernel_neon_end();

	return skcipher_walk_done(&walk, 0);
	}

	static struct skcipher_alg aes_algs[] = { {
	.base.cra_name = "__ecb(aes)",
	.base.cra_driver_name = "__ecb-aes-ce",
	.base.cra_priority = 300,
	.base.cra_flags = CRYPTO_ALG_INTERNAL,
	.base.cra_blocksize = AES_BLOCK_SIZE,
	.base.cra_ctxsize = sizeof(struct crypto_aes_ctx),
	.base.cra_module = THIS_MODULE,

	.min_keysize = AES_MIN_KEY_SIZE,
	.max_keysize = AES_MAX_KEY_SIZE,
	.setkey = ce_aes_setkey,
	.encrypt = ecb_encrypt,
	.decrypt = ecb_decrypt,
	}, {
	.base.cra_name = "__cbc(aes)",
	.base.cra_driver_name = "__cbc-aes-ce",
	.base.cra_priority = 300,
	.base.cra_flags = CRYPTO_ALG_INTERNAL,
	.base.cra_blocksize = AES_BLOCK_SIZE,
	.base.cra_ctxsize = sizeof(struct crypto_aes_ctx),
	.base.cra_module = THIS_MODULE,

	.min_keysize = AES_MIN_KEY_SIZE,
	.max_keysize = AES_MAX_KEY_SIZE,
	.ivsize = AES_BLOCK_SIZE,
	.setkey = ce_aes_setkey,
	.encrypt = cbc_encrypt,
	.decrypt = cbc_decrypt,
	}, {
	.base.cra_name = "__cts(cbc(aes))",
	.base.cra_driver_name = "__cts-cbc-aes-ce",
	.base.cra_priority = 300,
	.base.cra_flags = CRYPTO_ALG_INTERNAL,
	.base.cra_blocksize = AES_BLOCK_SIZE,
	.base.cra_ctxsize = sizeof(struct crypto_aes_ctx),
	.base.cra_module = THIS_MODULE,

	.min_keysize = AES_MIN_KEY_SIZE,
	.max_keysize = AES_MAX_KEY_SIZE,
	.ivsize = AES_BLOCK_SIZE,
	.walksize = 2 * AES_BLOCK_SIZE,
	.setkey = ce_aes_setkey,
	.encrypt = cts_cbc_encrypt,
	.decrypt = cts_cbc_decrypt,
	}, {
	.base.cra_name = "__ctr(aes)",
	.base.cra_driver_name = "__ctr-aes-ce",
	.base.cra_priority = 300,
	.base.cra_flags = CRYPTO_ALG_INTERNAL,
	.base.cra_blocksize = 1,
	.base.cra_ctxsize = sizeof(struct crypto_aes_ctx),
	.base.cra_module = THIS_MODULE,

	.min_keysize = AES_MIN_KEY_SIZE,
	.max_keysize = AES_MAX_KEY_SIZE,
	.ivsize = AES_BLOCK_SIZE,
	.chunksize = AES_BLOCK_SIZE,
	.setkey = ce_aes_setkey,
	.encrypt = ctr_encrypt,
	.decrypt = ctr_encrypt,
	}, {
	.base.cra_name = "ctr(aes)",
	.base.cra_driver_name = "ctr-aes-ce-sync",
	.base.cra_priority = 300 - 1,
	.base.cra_blocksize = 1,
	.base.cra_ctxsize = sizeof(struct crypto_aes_ctx),
	.base.cra_module = THIS_MODULE,

	.min_keysize = AES_MIN_KEY_SIZE,
	.max_keysize = AES_MAX_KEY_SIZE,
	.ivsize = AES_BLOCK_SIZE,
	.chunksize = AES_BLOCK_SIZE,
	.setkey = ce_aes_setkey,
	.encrypt = ctr_encrypt_sync,
	.decrypt = ctr_encrypt_sync,
	}, {
	.base.cra_name = "__xts(aes)",
	.base.cra_driver_name = "__xts-aes-ce",
	.base.cra_priority = 300,
	.base.cra_flags = CRYPTO_ALG_INTERNAL,
	.base.cra_blocksize = AES_BLOCK_SIZE,
	.base.cra_ctxsize = sizeof(struct crypto_aes_xts_ctx),
	.base.cra_module = THIS_MODULE,

	.min_keysize = 2 * AES_MIN_KEY_SIZE,
	.max_keysize = 2 * AES_MAX_KEY_SIZE,
	.ivsize = AES_BLOCK_SIZE,
	.walksize = 2 * AES_BLOCK_SIZE,
	.setkey = xts_set_key,
	.encrypt = xts_encrypt,
	.decrypt = xts_decrypt,
	} };

	static struct simd_skcipher_alg *aes_simd_algs[ARRAY_SIZE(aes_algs)];

	static void aes_exit(void)
	{
	int i;

	for (i = 0; i < ARRAY_SIZE(aes_simd_algs) && aes_simd_algs[i]; i++)
	simd_skcipher_free(aes_simd_algs[i]);

	crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
	}

	static int __init aes_init(void)
	{
	struct simd_skcipher_alg *simd;
	const char *basename;
	const char *algname;
	const char *drvname;
	int err;
	int i;

	err = crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
	if (err)
	return err;

	for (i = 0; i < ARRAY_SIZE(aes_algs); i++) {
	if (!(aes_algs[i].base.cra_flags & CRYPTO_ALG_INTERNAL))
	continue;

	algname = aes_algs[i].base.cra_name + 2;
	drvname = aes_algs[i].base.cra_driver_name + 2;
	basename = aes_algs[i].base.cra_driver_name;
	simd = simd_skcipher_create_compat(algname, drvname, basename);
	err = PTR_ERR(simd);
	if (IS_ERR(simd))
	goto unregister_simds;

	aes_simd_algs[i] = simd;
	}

	return 0;

	unregister_simds:
	aes_exit();
	return err;
	}

	module_cpu_feature_match(AES, aes_init);
	module_exit(aes_exit);