arch/arm64/crypto/ghash-ce-glue.c - third_party/linux - Git at Google

 /*
  * Accelerated GHASH implementation with ARMv8 PMULL instructions.
  *
  * Copyright (C) 2014 - 2017 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 <asm/simd.h>
 #include <asm/unaligned.h>
 #include <crypto/aes.h>
 #include <crypto/algapi.h>
 #include <crypto/b128ops.h>
 #include <crypto/gf128mul.h>
 #include <crypto/internal/aead.h>
 #include <crypto/internal/hash.h>
 #include <crypto/internal/skcipher.h>
 #include <crypto/scatterwalk.h>
 #include <linux/cpufeature.h>
 #include <linux/crypto.h>
 #include <linux/module.h>

 MODULE_DESCRIPTION("GHASH and AES-GCM using ARMv8 Crypto Extensions");
 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
 MODULE_LICENSE("GPL v2");
 MODULE_ALIAS_CRYPTO("ghash");

 #define GHASH_BLOCK_SIZE	16
 #define GHASH_DIGEST_SIZE	16
 #define GCM_IV_SIZE		12

 struct ghash_key {
 	u64 a;
 	u64 b;
 	be128 k;
 };

 struct ghash_desc_ctx {
 	u64 digest[GHASH_DIGEST_SIZE/sizeof(u64)];
 	u8 buf[GHASH_BLOCK_SIZE];
 	u32 count;
 };

 struct gcm_aes_ctx {
 	struct crypto_aes_ctx	aes_key;
 	struct ghash_key	ghash_key;
 };

 asmlinkage void pmull_ghash_update_p64(int blocks, u64 dg[], const char *src,
 				       struct ghash_key const *k,
 				       const char *head);

 asmlinkage void pmull_ghash_update_p8(int blocks, u64 dg[], const char *src,
 				      struct ghash_key const *k,
 				      const char *head);

 static void (*pmull_ghash_update)(int blocks, u64 dg[], const char *src,
 				  struct ghash_key const *k,
 				  const char *head);

 asmlinkage void pmull_gcm_encrypt(int blocks, u64 dg[], u8 dst[],
 				  const u8 src[], struct ghash_key const *k,
 				  u8 ctr[], u32 const rk[], int rounds,
 				  u8 ks[]);

 asmlinkage void pmull_gcm_decrypt(int blocks, u64 dg[], u8 dst[],
 				  const u8 src[], struct ghash_key const *k,
 				  u8 ctr[], u32 const rk[], int rounds);

 asmlinkage void pmull_gcm_encrypt_block(u8 dst[], u8 const src[],
 					u32 const rk[], int rounds);

 asmlinkage void __aes_arm64_encrypt(u32 *rk, u8 *out, const u8 *in, int rounds);

 static int ghash_init(struct shash_desc *desc)
 {
 	struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);

 	*ctx = (struct ghash_desc_ctx){};
 	return 0;
 }

 static void ghash_do_update(int blocks, u64 dg[], const char *src,
 			    struct ghash_key *key, const char *head)
 {
 	if (likely(may_use_simd())) {
 		kernel_neon_begin();
 		pmull_ghash_update(blocks, dg, src, key, head);
 		kernel_neon_end();
 	} else {
 		be128 dst = { cpu_to_be64(dg[1]), cpu_to_be64(dg[0]) };

 		do {
 			const u8 *in = src;

 			if (head) {
 				in = head;
 				blocks++;
 				head = NULL;
 			} else {
 				src += GHASH_BLOCK_SIZE;
 			}

 			crypto_xor((u8 *)&dst, in, GHASH_BLOCK_SIZE);
 			gf128mul_lle(&dst, &key->k);
 		} while (--blocks);

 		dg[0] = be64_to_cpu(dst.b);
 		dg[1] = be64_to_cpu(dst.a);
 	}
 }

 static int ghash_update(struct shash_desc *desc, const u8 *src,
 			unsigned int len)
 {
 	struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
 	unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;

 	ctx->count += len;

 	if ((partial + len) >= GHASH_BLOCK_SIZE) {
 		struct ghash_key *key = crypto_shash_ctx(desc->tfm);
 		int blocks;

 		if (partial) {
 			int p = GHASH_BLOCK_SIZE - partial;

 			memcpy(ctx->buf + partial, src, p);
 			src += p;
 			len -= p;
 		}

 		blocks = len / GHASH_BLOCK_SIZE;
 		len %= GHASH_BLOCK_SIZE;

 		ghash_do_update(blocks, ctx->digest, src, key,
 				partial ? ctx->buf : NULL);

 		src += blocks * GHASH_BLOCK_SIZE;
 		partial = 0;
 	}
 	if (len)
 		memcpy(ctx->buf + partial, src, len);
 	return 0;
 }

 static int ghash_final(struct shash_desc *desc, u8 *dst)
 {
 	struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
 	unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;

 	if (partial) {
 		struct ghash_key *key = crypto_shash_ctx(desc->tfm);

 		memset(ctx->buf + partial, 0, GHASH_BLOCK_SIZE - partial);

 		ghash_do_update(1, ctx->digest, ctx->buf, key, NULL);
 	}
 	put_unaligned_be64(ctx->digest[1], dst);
 	put_unaligned_be64(ctx->digest[0], dst + 8);

 	*ctx = (struct ghash_desc_ctx){};
 	return 0;
 }

 static int __ghash_setkey(struct ghash_key *key,
 			  const u8 *inkey, unsigned int keylen)
 {
 	u64 a, b;

 	/* needed for the fallback */
 	memcpy(&key->k, inkey, GHASH_BLOCK_SIZE);

 	/* perform multiplication by 'x' in GF(2^128) */
 	b = get_unaligned_be64(inkey);
 	a = get_unaligned_be64(inkey + 8);

 	key->a = (a << 1) | (b >> 63);
 	key->b = (b << 1) | (a >> 63);

 	if (b >> 63)
 		key->b ^= 0xc200000000000000UL;

 	return 0;
 }

 static int ghash_setkey(struct crypto_shash *tfm,
 			const u8 *inkey, unsigned int keylen)
 {
 	struct ghash_key *key = crypto_shash_ctx(tfm);

 	if (keylen != GHASH_BLOCK_SIZE) {
 		crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 		return -EINVAL;
 	}

 	return __ghash_setkey(key, inkey, keylen);
 }

 static struct shash_alg ghash_alg = {
 	.base.cra_name		= "ghash",
 	.base.cra_driver_name	= "ghash-ce",
 	.base.cra_priority	= 200,
 	.base.cra_flags		= CRYPTO_ALG_TYPE_SHASH,
 	.base.cra_blocksize	= GHASH_BLOCK_SIZE,
 	.base.cra_ctxsize	= sizeof(struct ghash_key),
 	.base.cra_module	= THIS_MODULE,

 	.digestsize		= GHASH_DIGEST_SIZE,
 	.init			= ghash_init,
 	.update			= ghash_update,
 	.final			= ghash_final,
 	.setkey			= ghash_setkey,
 	.descsize		= sizeof(struct ghash_desc_ctx),
 };

 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 gcm_setkey(struct crypto_aead *tfm, const u8 *inkey,
 		      unsigned int keylen)
 {
 	struct gcm_aes_ctx *ctx = crypto_aead_ctx(tfm);
 	u8 key[GHASH_BLOCK_SIZE];
 	int ret;

 	ret = crypto_aes_expand_key(&ctx->aes_key, inkey, keylen);
 	if (ret) {
 		tfm->base.crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
 		return -EINVAL;
 	}

 	__aes_arm64_encrypt(ctx->aes_key.key_enc, key, (u8[AES_BLOCK_SIZE]){},
 			    num_rounds(&ctx->aes_key));

 	return __ghash_setkey(&ctx->ghash_key, key, sizeof(key));
 }

 static int gcm_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
 {
 	switch (authsize) {
 	case 4:
 	case 8:
 	case 12 ... 16:
 		break;
 	default:
 		return -EINVAL;
 	}
 	return 0;
 }

 static void gcm_update_mac(u64 dg[], const u8 *src, int count, u8 buf[],
 			   int *buf_count, struct gcm_aes_ctx *ctx)
 {
 	if (*buf_count > 0) {
 		int buf_added = min(count, GHASH_BLOCK_SIZE - *buf_count);

 		memcpy(&buf[*buf_count], src, buf_added);

 		*buf_count += buf_added;
 		src += buf_added;
 		count -= buf_added;
 	}

 	if (count >= GHASH_BLOCK_SIZE || *buf_count == GHASH_BLOCK_SIZE) {
 		int blocks = count / GHASH_BLOCK_SIZE;

 		ghash_do_update(blocks, dg, src, &ctx->ghash_key,
 				*buf_count ? buf : NULL);

 		src += blocks * GHASH_BLOCK_SIZE;
 		count %= GHASH_BLOCK_SIZE;
 		*buf_count = 0;
 	}

 	if (count > 0) {
 		memcpy(buf, src, count);
 		*buf_count = count;
 	}
 }

 static void gcm_calculate_auth_mac(struct aead_request *req, u64 dg[])
 {
 	struct crypto_aead *aead = crypto_aead_reqtfm(req);
 	struct gcm_aes_ctx *ctx = crypto_aead_ctx(aead);
 	u8 buf[GHASH_BLOCK_SIZE];
 	struct scatter_walk walk;
 	u32 len = req->assoclen;
 	int buf_count = 0;

 	scatterwalk_start(&walk, req->src);

 	do {
 		u32 n = scatterwalk_clamp(&walk, len);
 		u8 *p;

 		if (!n) {
 			scatterwalk_start(&walk, sg_next(walk.sg));
 			n = scatterwalk_clamp(&walk, len);
 		}
 		p = scatterwalk_map(&walk);

 		gcm_update_mac(dg, p, n, buf, &buf_count, ctx);
 		len -= n;

 		scatterwalk_unmap(p);
 		scatterwalk_advance(&walk, n);
 		scatterwalk_done(&walk, 0, len);
 	} while (len);

 	if (buf_count) {
 		memset(&buf[buf_count], 0, GHASH_BLOCK_SIZE - buf_count);
 		ghash_do_update(1, dg, buf, &ctx->ghash_key, NULL);
 	}
 }

 static void gcm_final(struct aead_request *req, struct gcm_aes_ctx *ctx,
 		      u64 dg[], u8 tag[], int cryptlen)
 {
 	u8 mac[AES_BLOCK_SIZE];
 	u128 lengths;

 	lengths.a = cpu_to_be64(req->assoclen * 8);
 	lengths.b = cpu_to_be64(cryptlen * 8);

 	ghash_do_update(1, dg, (void *)&lengths, &ctx->ghash_key, NULL);

 	put_unaligned_be64(dg[1], mac);
 	put_unaligned_be64(dg[0], mac + 8);

 	crypto_xor(tag, mac, AES_BLOCK_SIZE);
 }

 static int gcm_encrypt(struct aead_request *req)
 {
 	struct crypto_aead *aead = crypto_aead_reqtfm(req);
 	struct gcm_aes_ctx *ctx = crypto_aead_ctx(aead);
 	struct skcipher_walk walk;
 	u8 iv[AES_BLOCK_SIZE];
 	u8 ks[AES_BLOCK_SIZE];
 	u8 tag[AES_BLOCK_SIZE];
 	u64 dg[2] = {};
 	int err;

 	if (req->assoclen)
 		gcm_calculate_auth_mac(req, dg);

 	memcpy(iv, req->iv, GCM_IV_SIZE);
 	put_unaligned_be32(1, iv + GCM_IV_SIZE);

 	if (likely(may_use_simd())) {
 		kernel_neon_begin();

 		pmull_gcm_encrypt_block(tag, iv, ctx->aes_key.key_enc,
 					num_rounds(&ctx->aes_key));
 		put_unaligned_be32(2, iv + GCM_IV_SIZE);
 		pmull_gcm_encrypt_block(ks, iv, NULL,
 					num_rounds(&ctx->aes_key));
 		put_unaligned_be32(3, iv + GCM_IV_SIZE);
 		kernel_neon_end();

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

 		while (walk.nbytes >= AES_BLOCK_SIZE) {
 			int blocks = walk.nbytes / AES_BLOCK_SIZE;

 			kernel_neon_begin();
 			pmull_gcm_encrypt(blocks, dg, walk.dst.virt.addr,
 					  walk.src.virt.addr, &ctx->ghash_key,
 					  iv, ctx->aes_key.key_enc,
 					  num_rounds(&ctx->aes_key), ks);
 			kernel_neon_end();

 			err = skcipher_walk_done(&walk,
 						 walk.nbytes % AES_BLOCK_SIZE);
 		}
 	} else {
 		__aes_arm64_encrypt(ctx->aes_key.key_enc, tag, iv,
 				    num_rounds(&ctx->aes_key));
 		put_unaligned_be32(2, iv + GCM_IV_SIZE);

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

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

 			do {
 				__aes_arm64_encrypt(ctx->aes_key.key_enc,
 						    ks, iv,
 						    num_rounds(&ctx->aes_key));
 				crypto_xor_cpy(dst, src, ks, AES_BLOCK_SIZE);
 				crypto_inc(iv, AES_BLOCK_SIZE);

 				dst += AES_BLOCK_SIZE;
 				src += AES_BLOCK_SIZE;
 			} while (--blocks > 0);

 			ghash_do_update(walk.nbytes / AES_BLOCK_SIZE, dg,
 					walk.dst.virt.addr, &ctx->ghash_key,
 					NULL);

 			err = skcipher_walk_done(&walk,
 						 walk.nbytes % AES_BLOCK_SIZE);
 		}
 		if (walk.nbytes)
 			__aes_arm64_encrypt(ctx->aes_key.key_enc, ks, iv,
 					    num_rounds(&ctx->aes_key));
 	}

 	/* handle the tail */
 	if (walk.nbytes) {
 		u8 buf[GHASH_BLOCK_SIZE];

 		crypto_xor_cpy(walk.dst.virt.addr, walk.src.virt.addr, ks,
 			       walk.nbytes);

 		memcpy(buf, walk.dst.virt.addr, walk.nbytes);
 		memset(buf + walk.nbytes, 0, GHASH_BLOCK_SIZE - walk.nbytes);
 		ghash_do_update(1, dg, buf, &ctx->ghash_key, NULL);

 		err = skcipher_walk_done(&walk, 0);
 	}

 	if (err)
 		return err;

 	gcm_final(req, ctx, dg, tag, req->cryptlen);

 	/* copy authtag to end of dst */
 	scatterwalk_map_and_copy(tag, req->dst, req->assoclen + req->cryptlen,
 				 crypto_aead_authsize(aead), 1);

 	return 0;
 }

 static int gcm_decrypt(struct aead_request *req)
 {
 	struct crypto_aead *aead = crypto_aead_reqtfm(req);
 	struct gcm_aes_ctx *ctx = crypto_aead_ctx(aead);
 	unsigned int authsize = crypto_aead_authsize(aead);
 	struct skcipher_walk walk;
 	u8 iv[AES_BLOCK_SIZE];
 	u8 tag[AES_BLOCK_SIZE];
 	u8 buf[GHASH_BLOCK_SIZE];
 	u64 dg[2] = {};
 	int err;

 	if (req->assoclen)
 		gcm_calculate_auth_mac(req, dg);

 	memcpy(iv, req->iv, GCM_IV_SIZE);
 	put_unaligned_be32(1, iv + GCM_IV_SIZE);

 	if (likely(may_use_simd())) {
 		kernel_neon_begin();

 		pmull_gcm_encrypt_block(tag, iv, ctx->aes_key.key_enc,
 					num_rounds(&ctx->aes_key));
 		put_unaligned_be32(2, iv + GCM_IV_SIZE);
 		kernel_neon_end();

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

 		while (walk.nbytes >= AES_BLOCK_SIZE) {
 			int blocks = walk.nbytes / AES_BLOCK_SIZE;

 			kernel_neon_begin();
 			pmull_gcm_decrypt(blocks, dg, walk.dst.virt.addr,
 					  walk.src.virt.addr, &ctx->ghash_key,
 					  iv, ctx->aes_key.key_enc,
 					  num_rounds(&ctx->aes_key));
 			kernel_neon_end();

 			err = skcipher_walk_done(&walk,
 						 walk.nbytes % AES_BLOCK_SIZE);
 		}
 		if (walk.nbytes) {
 			kernel_neon_begin();
 			pmull_gcm_encrypt_block(iv, iv, ctx->aes_key.key_enc,
 						num_rounds(&ctx->aes_key));
 			kernel_neon_end();
 		}

 	} else {
 		__aes_arm64_encrypt(ctx->aes_key.key_enc, tag, iv,
 				    num_rounds(&ctx->aes_key));
 		put_unaligned_be32(2, iv + GCM_IV_SIZE);

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

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

 			ghash_do_update(blocks, dg, walk.src.virt.addr,
 					&ctx->ghash_key, NULL);

 			do {
 				__aes_arm64_encrypt(ctx->aes_key.key_enc,
 						    buf, iv,
 						    num_rounds(&ctx->aes_key));
 				crypto_xor_cpy(dst, src, buf, AES_BLOCK_SIZE);
 				crypto_inc(iv, AES_BLOCK_SIZE);

 				dst += AES_BLOCK_SIZE;
 				src += AES_BLOCK_SIZE;
 			} while (--blocks > 0);

 			err = skcipher_walk_done(&walk,
 						 walk.nbytes % AES_BLOCK_SIZE);
 		}
 		if (walk.nbytes)
 			__aes_arm64_encrypt(ctx->aes_key.key_enc, iv, iv,
 					    num_rounds(&ctx->aes_key));
 	}

 	/* handle the tail */
 	if (walk.nbytes) {
 		memcpy(buf, walk.src.virt.addr, walk.nbytes);
 		memset(buf + walk.nbytes, 0, GHASH_BLOCK_SIZE - walk.nbytes);
 		ghash_do_update(1, dg, buf, &ctx->ghash_key, NULL);

 		crypto_xor_cpy(walk.dst.virt.addr, walk.src.virt.addr, iv,
 			       walk.nbytes);

 		err = skcipher_walk_done(&walk, 0);
 	}

 	if (err)
 		return err;

 	gcm_final(req, ctx, dg, tag, req->cryptlen - authsize);

 	/* compare calculated auth tag with the stored one */
 	scatterwalk_map_and_copy(buf, req->src,
 				 req->assoclen + req->cryptlen - authsize,
 				 authsize, 0);

 	if (crypto_memneq(tag, buf, authsize))
 		return -EBADMSG;
 	return 0;
 }

 static struct aead_alg gcm_aes_alg = {
 	.ivsize			= GCM_IV_SIZE,
 	.chunksize		= AES_BLOCK_SIZE,
 	.maxauthsize		= AES_BLOCK_SIZE,
 	.setkey			= gcm_setkey,
 	.setauthsize		= gcm_setauthsize,
 	.encrypt		= gcm_encrypt,
 	.decrypt		= gcm_decrypt,

 	.base.cra_name		= "gcm(aes)",
 	.base.cra_driver_name	= "gcm-aes-ce",
 	.base.cra_priority	= 300,
 	.base.cra_blocksize	= 1,
 	.base.cra_ctxsize	= sizeof(struct gcm_aes_ctx),
 	.base.cra_module	= THIS_MODULE,
 };

 static int __init ghash_ce_mod_init(void)
 {
 	int ret;

 	if (!(elf_hwcap & HWCAP_ASIMD))
 		return -ENODEV;

 	if (elf_hwcap & HWCAP_PMULL)
 		pmull_ghash_update = pmull_ghash_update_p64;

 	else
 		pmull_ghash_update = pmull_ghash_update_p8;

 	ret = crypto_register_shash(&ghash_alg);
 	if (ret)
 		return ret;

 	if (elf_hwcap & HWCAP_PMULL) {
 		ret = crypto_register_aead(&gcm_aes_alg);
 		if (ret)
 			crypto_unregister_shash(&ghash_alg);
 	}
 	return ret;
 }

 static void __exit ghash_ce_mod_exit(void)
 {
 	crypto_unregister_shash(&ghash_alg);
 	crypto_unregister_aead(&gcm_aes_alg);
 }

 static const struct cpu_feature ghash_cpu_feature[] = {
 	{ cpu_feature(PMULL) }, { }
 };
 MODULE_DEVICE_TABLE(cpu, ghash_cpu_feature);

 module_init(ghash_ce_mod_init);
 module_exit(ghash_ce_mod_exit);
	/*
	* Accelerated GHASH implementation with ARMv8 PMULL instructions.
	*
	* Copyright (C) 2014 - 2017 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 <asm/simd.h>
	#include <asm/unaligned.h>
	#include <crypto/aes.h>
	#include <crypto/algapi.h>
	#include <crypto/b128ops.h>
	#include <crypto/gf128mul.h>
	#include <crypto/internal/aead.h>
	#include <crypto/internal/hash.h>
	#include <crypto/internal/skcipher.h>
	#include <crypto/scatterwalk.h>
	#include <linux/cpufeature.h>
	#include <linux/crypto.h>
	#include <linux/module.h>

	MODULE_DESCRIPTION("GHASH and AES-GCM using ARMv8 Crypto Extensions");
	MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
	MODULE_LICENSE("GPL v2");
	MODULE_ALIAS_CRYPTO("ghash");

	#define GHASH_BLOCK_SIZE 16
	#define GHASH_DIGEST_SIZE 16
	#define GCM_IV_SIZE 12

	struct ghash_key {
	u64 a;
	u64 b;
	be128 k;
	};

	struct ghash_desc_ctx {
	u64 digest[GHASH_DIGEST_SIZE/sizeof(u64)];
	u8 buf[GHASH_BLOCK_SIZE];
	u32 count;
	};

	struct gcm_aes_ctx {
	struct crypto_aes_ctx aes_key;
	struct ghash_key ghash_key;
	};

	asmlinkage void pmull_ghash_update_p64(int blocks, u64 dg[], const char *src,
	struct ghash_key const *k,
	const char *head);

	asmlinkage void pmull_ghash_update_p8(int blocks, u64 dg[], const char *src,
	struct ghash_key const *k,
	const char *head);

	static void (pmull_ghash_update)(int blocks, u64 dg[], const char src,
	struct ghash_key const *k,
	const char *head);

	asmlinkage void pmull_gcm_encrypt(int blocks, u64 dg[], u8 dst[],
	const u8 src[], struct ghash_key const *k,
	u8 ctr[], u32 const rk[], int rounds,
	u8 ks[]);

	asmlinkage void pmull_gcm_decrypt(int blocks, u64 dg[], u8 dst[],
	const u8 src[], struct ghash_key const *k,
	u8 ctr[], u32 const rk[], int rounds);

	asmlinkage void pmull_gcm_encrypt_block(u8 dst[], u8 const src[],
	u32 const rk[], int rounds);

	asmlinkage void __aes_arm64_encrypt(u32 rk, u8 out, const u8 *in, int rounds);

	static int ghash_init(struct shash_desc *desc)
	{
	struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);

	*ctx = (struct ghash_desc_ctx){};
	return 0;
	}

	static void ghash_do_update(int blocks, u64 dg[], const char *src,
	struct ghash_key key, const char head)
	{
	if (likely(may_use_simd())) {
	kernel_neon_begin();
	pmull_ghash_update(blocks, dg, src, key, head);
	kernel_neon_end();
	} else {
	be128 dst = { cpu_to_be64(dg[1]), cpu_to_be64(dg[0]) };

	do {
	const u8 *in = src;

	if (head) {
	in = head;
	blocks++;
	head = NULL;
	} else {
	src += GHASH_BLOCK_SIZE;
	}

	crypto_xor((u8 *)&dst, in, GHASH_BLOCK_SIZE);
	gf128mul_lle(&dst, &key->k);
	} while (--blocks);

	dg[0] = be64_to_cpu(dst.b);
	dg[1] = be64_to_cpu(dst.a);
	}
	}

	static int ghash_update(struct shash_desc desc, const u8 src,
	unsigned int len)
	{
	struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
	unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;

	ctx->count += len;

	if ((partial + len) >= GHASH_BLOCK_SIZE) {
	struct ghash_key *key = crypto_shash_ctx(desc->tfm);
	int blocks;

	if (partial) {
	int p = GHASH_BLOCK_SIZE - partial;

	memcpy(ctx->buf + partial, src, p);
	src += p;
	len -= p;
	}

	blocks = len / GHASH_BLOCK_SIZE;
	len %= GHASH_BLOCK_SIZE;

	ghash_do_update(blocks, ctx->digest, src, key,
	partial ? ctx->buf : NULL);

	src += blocks * GHASH_BLOCK_SIZE;
	partial = 0;
	}
	if (len)
	memcpy(ctx->buf + partial, src, len);
	return 0;
	}

	static int ghash_final(struct shash_desc desc, u8 dst)
	{
	struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
	unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;

	if (partial) {
	struct ghash_key *key = crypto_shash_ctx(desc->tfm);

	memset(ctx->buf + partial, 0, GHASH_BLOCK_SIZE - partial);

	ghash_do_update(1, ctx->digest, ctx->buf, key, NULL);
	}
	put_unaligned_be64(ctx->digest[1], dst);
	put_unaligned_be64(ctx->digest[0], dst + 8);

	*ctx = (struct ghash_desc_ctx){};
	return 0;
	}

	static int __ghash_setkey(struct ghash_key *key,
	const u8 *inkey, unsigned int keylen)
	{
	u64 a, b;

	/* needed for the fallback */
	memcpy(&key->k, inkey, GHASH_BLOCK_SIZE);

	/* perform multiplication by 'x' in GF(2^128) */
	b = get_unaligned_be64(inkey);
	a = get_unaligned_be64(inkey + 8);

	key->a = (a << 1) \| (b >> 63);
	key->b = (b << 1) \| (a >> 63);

	if (b >> 63)
	key->b ^= 0xc200000000000000UL;

	return 0;
	}

	static int ghash_setkey(struct crypto_shash *tfm,
	const u8 *inkey, unsigned int keylen)
	{
	struct ghash_key *key = crypto_shash_ctx(tfm);

	if (keylen != GHASH_BLOCK_SIZE) {
	crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
	return -EINVAL;
	}

	return __ghash_setkey(key, inkey, keylen);
	}

	static struct shash_alg ghash_alg = {
	.base.cra_name = "ghash",
	.base.cra_driver_name = "ghash-ce",
	.base.cra_priority = 200,
	.base.cra_flags = CRYPTO_ALG_TYPE_SHASH,
	.base.cra_blocksize = GHASH_BLOCK_SIZE,
	.base.cra_ctxsize = sizeof(struct ghash_key),
	.base.cra_module = THIS_MODULE,

	.digestsize = GHASH_DIGEST_SIZE,
	.init = ghash_init,
	.update = ghash_update,
	.final = ghash_final,
	.setkey = ghash_setkey,
	.descsize = sizeof(struct ghash_desc_ctx),
	};

	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 gcm_setkey(struct crypto_aead tfm, const u8 inkey,
	unsigned int keylen)
	{
	struct gcm_aes_ctx *ctx = crypto_aead_ctx(tfm);
	u8 key[GHASH_BLOCK_SIZE];
	int ret;

	ret = crypto_aes_expand_key(&ctx->aes_key, inkey, keylen);
	if (ret) {
	tfm->base.crt_flags \|= CRYPTO_TFM_RES_BAD_KEY_LEN;
	return -EINVAL;
	}

	__aes_arm64_encrypt(ctx->aes_key.key_enc, key, (u8[AES_BLOCK_SIZE]){},
	num_rounds(&ctx->aes_key));

	return __ghash_setkey(&ctx->ghash_key, key, sizeof(key));
	}

	static int gcm_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
	{
	switch (authsize) {
	case 4:
	case 8:
	case 12 ... 16:
	break;
	default:
	return -EINVAL;
	}
	return 0;
	}

	static void gcm_update_mac(u64 dg[], const u8 *src, int count, u8 buf[],
	int buf_count, struct gcm_aes_ctx ctx)
	{
	if (*buf_count > 0) {
	int buf_added = min(count, GHASH_BLOCK_SIZE - *buf_count);

	memcpy(&buf[*buf_count], src, buf_added);

	*buf_count += buf_added;
	src += buf_added;
	count -= buf_added;
	}

	if (count >= GHASH_BLOCK_SIZE \|\| *buf_count == GHASH_BLOCK_SIZE) {
	int blocks = count / GHASH_BLOCK_SIZE;

	ghash_do_update(blocks, dg, src, &ctx->ghash_key,
	*buf_count ? buf : NULL);

	src += blocks * GHASH_BLOCK_SIZE;
	count %= GHASH_BLOCK_SIZE;
	*buf_count = 0;
	}

	if (count > 0) {
	memcpy(buf, src, count);
	*buf_count = count;
	}
	}

	static void gcm_calculate_auth_mac(struct aead_request *req, u64 dg[])
	{
	struct crypto_aead *aead = crypto_aead_reqtfm(req);
	struct gcm_aes_ctx *ctx = crypto_aead_ctx(aead);
	u8 buf[GHASH_BLOCK_SIZE];
	struct scatter_walk walk;
	u32 len = req->assoclen;
	int buf_count = 0;

	scatterwalk_start(&walk, req->src);

	do {
	u32 n = scatterwalk_clamp(&walk, len);
	u8 *p;

	if (!n) {
	scatterwalk_start(&walk, sg_next(walk.sg));
	n = scatterwalk_clamp(&walk, len);
	}
	p = scatterwalk_map(&walk);

	gcm_update_mac(dg, p, n, buf, &buf_count, ctx);
	len -= n;

	scatterwalk_unmap(p);
	scatterwalk_advance(&walk, n);
	scatterwalk_done(&walk, 0, len);
	} while (len);

	if (buf_count) {
	memset(&buf[buf_count], 0, GHASH_BLOCK_SIZE - buf_count);
	ghash_do_update(1, dg, buf, &ctx->ghash_key, NULL);
	}
	}

	static void gcm_final(struct aead_request req, struct gcm_aes_ctx ctx,
	u64 dg[], u8 tag[], int cryptlen)
	{
	u8 mac[AES_BLOCK_SIZE];
	u128 lengths;

	lengths.a = cpu_to_be64(req->assoclen * 8);
	lengths.b = cpu_to_be64(cryptlen * 8);

	ghash_do_update(1, dg, (void *)&lengths, &ctx->ghash_key, NULL);

	put_unaligned_be64(dg[1], mac);
	put_unaligned_be64(dg[0], mac + 8);

	crypto_xor(tag, mac, AES_BLOCK_SIZE);
	}

	static int gcm_encrypt(struct aead_request *req)
	{
	struct crypto_aead *aead = crypto_aead_reqtfm(req);
	struct gcm_aes_ctx *ctx = crypto_aead_ctx(aead);
	struct skcipher_walk walk;
	u8 iv[AES_BLOCK_SIZE];
	u8 ks[AES_BLOCK_SIZE];
	u8 tag[AES_BLOCK_SIZE];
	u64 dg[2] = {};
	int err;

	if (req->assoclen)
	gcm_calculate_auth_mac(req, dg);

	memcpy(iv, req->iv, GCM_IV_SIZE);
	put_unaligned_be32(1, iv + GCM_IV_SIZE);

	if (likely(may_use_simd())) {
	kernel_neon_begin();

	pmull_gcm_encrypt_block(tag, iv, ctx->aes_key.key_enc,
	num_rounds(&ctx->aes_key));
	put_unaligned_be32(2, iv + GCM_IV_SIZE);
	pmull_gcm_encrypt_block(ks, iv, NULL,
	num_rounds(&ctx->aes_key));
	put_unaligned_be32(3, iv + GCM_IV_SIZE);
	kernel_neon_end();

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

	while (walk.nbytes >= AES_BLOCK_SIZE) {
	int blocks = walk.nbytes / AES_BLOCK_SIZE;

	kernel_neon_begin();
	pmull_gcm_encrypt(blocks, dg, walk.dst.virt.addr,
	walk.src.virt.addr, &ctx->ghash_key,
	iv, ctx->aes_key.key_enc,
	num_rounds(&ctx->aes_key), ks);
	kernel_neon_end();

	err = skcipher_walk_done(&walk,
	walk.nbytes % AES_BLOCK_SIZE);
	}
	} else {
	__aes_arm64_encrypt(ctx->aes_key.key_enc, tag, iv,
	num_rounds(&ctx->aes_key));
	put_unaligned_be32(2, iv + GCM_IV_SIZE);

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

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

	do {
	__aes_arm64_encrypt(ctx->aes_key.key_enc,
	ks, iv,
	num_rounds(&ctx->aes_key));
	crypto_xor_cpy(dst, src, ks, AES_BLOCK_SIZE);
	crypto_inc(iv, AES_BLOCK_SIZE);

	dst += AES_BLOCK_SIZE;
	src += AES_BLOCK_SIZE;
	} while (--blocks > 0);

	ghash_do_update(walk.nbytes / AES_BLOCK_SIZE, dg,
	walk.dst.virt.addr, &ctx->ghash_key,
	NULL);

	err = skcipher_walk_done(&walk,
	walk.nbytes % AES_BLOCK_SIZE);
	}
	if (walk.nbytes)
	__aes_arm64_encrypt(ctx->aes_key.key_enc, ks, iv,
	num_rounds(&ctx->aes_key));
	}

	/* handle the tail */
	if (walk.nbytes) {
	u8 buf[GHASH_BLOCK_SIZE];

	crypto_xor_cpy(walk.dst.virt.addr, walk.src.virt.addr, ks,
	walk.nbytes);

	memcpy(buf, walk.dst.virt.addr, walk.nbytes);
	memset(buf + walk.nbytes, 0, GHASH_BLOCK_SIZE - walk.nbytes);
	ghash_do_update(1, dg, buf, &ctx->ghash_key, NULL);

	err = skcipher_walk_done(&walk, 0);
	}

	if (err)
	return err;

	gcm_final(req, ctx, dg, tag, req->cryptlen);

	/* copy authtag to end of dst */
	scatterwalk_map_and_copy(tag, req->dst, req->assoclen + req->cryptlen,
	crypto_aead_authsize(aead), 1);

	return 0;
	}

	static int gcm_decrypt(struct aead_request *req)
	{
	struct crypto_aead *aead = crypto_aead_reqtfm(req);
	struct gcm_aes_ctx *ctx = crypto_aead_ctx(aead);
	unsigned int authsize = crypto_aead_authsize(aead);
	struct skcipher_walk walk;
	u8 iv[AES_BLOCK_SIZE];
	u8 tag[AES_BLOCK_SIZE];
	u8 buf[GHASH_BLOCK_SIZE];
	u64 dg[2] = {};
	int err;

	if (req->assoclen)
	gcm_calculate_auth_mac(req, dg);

	memcpy(iv, req->iv, GCM_IV_SIZE);
	put_unaligned_be32(1, iv + GCM_IV_SIZE);

	if (likely(may_use_simd())) {
	kernel_neon_begin();

	pmull_gcm_encrypt_block(tag, iv, ctx->aes_key.key_enc,
	num_rounds(&ctx->aes_key));
	put_unaligned_be32(2, iv + GCM_IV_SIZE);
	kernel_neon_end();

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

	while (walk.nbytes >= AES_BLOCK_SIZE) {
	int blocks = walk.nbytes / AES_BLOCK_SIZE;

	kernel_neon_begin();
	pmull_gcm_decrypt(blocks, dg, walk.dst.virt.addr,
	walk.src.virt.addr, &ctx->ghash_key,
	iv, ctx->aes_key.key_enc,
	num_rounds(&ctx->aes_key));
	kernel_neon_end();

	err = skcipher_walk_done(&walk,
	walk.nbytes % AES_BLOCK_SIZE);
	}
	if (walk.nbytes) {
	kernel_neon_begin();
	pmull_gcm_encrypt_block(iv, iv, ctx->aes_key.key_enc,
	num_rounds(&ctx->aes_key));
	kernel_neon_end();
	}

	} else {
	__aes_arm64_encrypt(ctx->aes_key.key_enc, tag, iv,
	num_rounds(&ctx->aes_key));
	put_unaligned_be32(2, iv + GCM_IV_SIZE);

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

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

	ghash_do_update(blocks, dg, walk.src.virt.addr,
	&ctx->ghash_key, NULL);

	do {
	__aes_arm64_encrypt(ctx->aes_key.key_enc,
	buf, iv,
	num_rounds(&ctx->aes_key));
	crypto_xor_cpy(dst, src, buf, AES_BLOCK_SIZE);
	crypto_inc(iv, AES_BLOCK_SIZE);

	dst += AES_BLOCK_SIZE;
	src += AES_BLOCK_SIZE;
	} while (--blocks > 0);

	err = skcipher_walk_done(&walk,
	walk.nbytes % AES_BLOCK_SIZE);
	}
	if (walk.nbytes)
	__aes_arm64_encrypt(ctx->aes_key.key_enc, iv, iv,
	num_rounds(&ctx->aes_key));
	}

	/* handle the tail */
	if (walk.nbytes) {
	memcpy(buf, walk.src.virt.addr, walk.nbytes);
	memset(buf + walk.nbytes, 0, GHASH_BLOCK_SIZE - walk.nbytes);
	ghash_do_update(1, dg, buf, &ctx->ghash_key, NULL);

	crypto_xor_cpy(walk.dst.virt.addr, walk.src.virt.addr, iv,
	walk.nbytes);

	err = skcipher_walk_done(&walk, 0);
	}

	if (err)
	return err;

	gcm_final(req, ctx, dg, tag, req->cryptlen - authsize);

	/* compare calculated auth tag with the stored one */
	scatterwalk_map_and_copy(buf, req->src,
	req->assoclen + req->cryptlen - authsize,
	authsize, 0);

	if (crypto_memneq(tag, buf, authsize))
	return -EBADMSG;
	return 0;
	}

	static struct aead_alg gcm_aes_alg = {
	.ivsize = GCM_IV_SIZE,
	.chunksize = AES_BLOCK_SIZE,
	.maxauthsize = AES_BLOCK_SIZE,
	.setkey = gcm_setkey,
	.setauthsize = gcm_setauthsize,
	.encrypt = gcm_encrypt,
	.decrypt = gcm_decrypt,

	.base.cra_name = "gcm(aes)",
	.base.cra_driver_name = "gcm-aes-ce",
	.base.cra_priority = 300,
	.base.cra_blocksize = 1,
	.base.cra_ctxsize = sizeof(struct gcm_aes_ctx),
	.base.cra_module = THIS_MODULE,
	};

	static int __init ghash_ce_mod_init(void)
	{
	int ret;

	if (!(elf_hwcap & HWCAP_ASIMD))
	return -ENODEV;

	if (elf_hwcap & HWCAP_PMULL)
	pmull_ghash_update = pmull_ghash_update_p64;

	else
	pmull_ghash_update = pmull_ghash_update_p8;

	ret = crypto_register_shash(&ghash_alg);
	if (ret)
	return ret;

	if (elf_hwcap & HWCAP_PMULL) {
	ret = crypto_register_aead(&gcm_aes_alg);
	if (ret)
	crypto_unregister_shash(&ghash_alg);
	}
	return ret;
	}

	static void __exit ghash_ce_mod_exit(void)
	{
	crypto_unregister_shash(&ghash_alg);
	crypto_unregister_aead(&gcm_aes_alg);
	}

	static const struct cpu_feature ghash_cpu_feature[] = {
	{ cpu_feature(PMULL) }, { }
	};
	MODULE_DEVICE_TABLE(cpu, ghash_cpu_feature);

	module_init(ghash_ce_mod_init);
	module_exit(ghash_ce_mod_exit);