/*
 * Glue code for the SHA512 Secure Hash Algorithm assembly implementation
 * using NEON instructions.
 *
 * Copyright © 2014 Jussi Kivilinna <jussi.kivilinna@iki.fi>
 *
 * This file is based on sha512_ssse3_glue.c:
 *   Copyright (C) 2013 Intel Corporation
 *   Author: Tim Chen <tim.c.chen@linux.intel.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 */

#include <crypto/internal/hash.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/cryptohash.h>
#include <linux/types.h>
#include <linux/string.h>
#include <crypto/sha.h>
#include <asm/byteorder.h>
#include <asm/simd.h>
#include <asm/neon.h>


static const u64 sha512_k[] = {
	0x428a2f98d728ae22ULL, 0x7137449123ef65cdULL,
	0xb5c0fbcfec4d3b2fULL, 0xe9b5dba58189dbbcULL,
	0x3956c25bf348b538ULL, 0x59f111f1b605d019ULL,
	0x923f82a4af194f9bULL, 0xab1c5ed5da6d8118ULL,
	0xd807aa98a3030242ULL, 0x12835b0145706fbeULL,
	0x243185be4ee4b28cULL, 0x550c7dc3d5ffb4e2ULL,
	0x72be5d74f27b896fULL, 0x80deb1fe3b1696b1ULL,
	0x9bdc06a725c71235ULL, 0xc19bf174cf692694ULL,
	0xe49b69c19ef14ad2ULL, 0xefbe4786384f25e3ULL,
	0x0fc19dc68b8cd5b5ULL, 0x240ca1cc77ac9c65ULL,
	0x2de92c6f592b0275ULL, 0x4a7484aa6ea6e483ULL,
	0x5cb0a9dcbd41fbd4ULL, 0x76f988da831153b5ULL,
	0x983e5152ee66dfabULL, 0xa831c66d2db43210ULL,
	0xb00327c898fb213fULL, 0xbf597fc7beef0ee4ULL,
	0xc6e00bf33da88fc2ULL, 0xd5a79147930aa725ULL,
	0x06ca6351e003826fULL, 0x142929670a0e6e70ULL,
	0x27b70a8546d22ffcULL, 0x2e1b21385c26c926ULL,
	0x4d2c6dfc5ac42aedULL, 0x53380d139d95b3dfULL,
	0x650a73548baf63deULL, 0x766a0abb3c77b2a8ULL,
	0x81c2c92e47edaee6ULL, 0x92722c851482353bULL,
	0xa2bfe8a14cf10364ULL, 0xa81a664bbc423001ULL,
	0xc24b8b70d0f89791ULL, 0xc76c51a30654be30ULL,
	0xd192e819d6ef5218ULL, 0xd69906245565a910ULL,
	0xf40e35855771202aULL, 0x106aa07032bbd1b8ULL,
	0x19a4c116b8d2d0c8ULL, 0x1e376c085141ab53ULL,
	0x2748774cdf8eeb99ULL, 0x34b0bcb5e19b48a8ULL,
	0x391c0cb3c5c95a63ULL, 0x4ed8aa4ae3418acbULL,
	0x5b9cca4f7763e373ULL, 0x682e6ff3d6b2b8a3ULL,
	0x748f82ee5defb2fcULL, 0x78a5636f43172f60ULL,
	0x84c87814a1f0ab72ULL, 0x8cc702081a6439ecULL,
	0x90befffa23631e28ULL, 0xa4506cebde82bde9ULL,
	0xbef9a3f7b2c67915ULL, 0xc67178f2e372532bULL,
	0xca273eceea26619cULL, 0xd186b8c721c0c207ULL,
	0xeada7dd6cde0eb1eULL, 0xf57d4f7fee6ed178ULL,
	0x06f067aa72176fbaULL, 0x0a637dc5a2c898a6ULL,
	0x113f9804bef90daeULL, 0x1b710b35131c471bULL,
	0x28db77f523047d84ULL, 0x32caab7b40c72493ULL,
	0x3c9ebe0a15c9bebcULL, 0x431d67c49c100d4cULL,
	0x4cc5d4becb3e42b6ULL, 0x597f299cfc657e2aULL,
	0x5fcb6fab3ad6faecULL, 0x6c44198c4a475817ULL
};


asmlinkage void sha512_transform_neon(u64 *digest, const void *data,
				      const u64 k[], unsigned int num_blks);


static int sha512_neon_init(struct shash_desc *desc)
{
	struct sha512_state *sctx = shash_desc_ctx(desc);

	sctx->state[0] = SHA512_H0;
	sctx->state[1] = SHA512_H1;
	sctx->state[2] = SHA512_H2;
	sctx->state[3] = SHA512_H3;
	sctx->state[4] = SHA512_H4;
	sctx->state[5] = SHA512_H5;
	sctx->state[6] = SHA512_H6;
	sctx->state[7] = SHA512_H7;
	sctx->count[0] = sctx->count[1] = 0;

	return 0;
}

static int __sha512_neon_update(struct shash_desc *desc, const u8 *data,
				unsigned int len, unsigned int partial)
{
	struct sha512_state *sctx = shash_desc_ctx(desc);
	unsigned int done = 0;

	sctx->count[0] += len;
	if (sctx->count[0] < len)
		sctx->count[1]++;

	if (partial) {
		done = SHA512_BLOCK_SIZE - partial;
		memcpy(sctx->buf + partial, data, done);
		sha512_transform_neon(sctx->state, sctx->buf, sha512_k, 1);
	}

	if (len - done >= SHA512_BLOCK_SIZE) {
		const unsigned int rounds = (len - done) / SHA512_BLOCK_SIZE;

		sha512_transform_neon(sctx->state, data + done, sha512_k,
				      rounds);

		done += rounds * SHA512_BLOCK_SIZE;
	}

	memcpy(sctx->buf, data + done, len - done);

	return 0;
}

static int sha512_neon_update(struct shash_desc *desc, const u8 *data,
			     unsigned int len)
{
	struct sha512_state *sctx = shash_desc_ctx(desc);
	unsigned int partial = sctx->count[0] % SHA512_BLOCK_SIZE;
	int res;

	/* Handle the fast case right here */
	if (partial + len < SHA512_BLOCK_SIZE) {
		sctx->count[0] += len;
		if (sctx->count[0] < len)
			sctx->count[1]++;
		memcpy(sctx->buf + partial, data, len);

		return 0;
	}

	if (!may_use_simd()) {
		res = crypto_sha512_update(desc, data, len);
	} else {
		kernel_neon_begin();
		res = __sha512_neon_update(desc, data, len, partial);
		kernel_neon_end();
	}

	return res;
}


/* Add padding and return the message digest. */
static int sha512_neon_final(struct shash_desc *desc, u8 *out)
{
	struct sha512_state *sctx = shash_desc_ctx(desc);
	unsigned int i, index, padlen;
	__be64 *dst = (__be64 *)out;
	__be64 bits[2];
	static const u8 padding[SHA512_BLOCK_SIZE] = { 0x80, };

	/* save number of bits */
	bits[1] = cpu_to_be64(sctx->count[0] << 3);
	bits[0] = cpu_to_be64(sctx->count[1] << 3 | sctx->count[0] >> 61);

	/* Pad out to 112 mod 128 and append length */
	index = sctx->count[0] & 0x7f;
	padlen = (index < 112) ? (112 - index) : ((128+112) - index);

	if (!may_use_simd()) {
		crypto_sha512_update(desc, padding, padlen);
		crypto_sha512_update(desc, (const u8 *)&bits, sizeof(bits));
	} else {
		kernel_neon_begin();
		/* We need to fill a whole block for __sha512_neon_update() */
		if (padlen <= 112) {
			sctx->count[0] += padlen;
			if (sctx->count[0] < padlen)
				sctx->count[1]++;
			memcpy(sctx->buf + index, padding, padlen);
		} else {
			__sha512_neon_update(desc, padding, padlen, index);
		}
		__sha512_neon_update(desc, (const u8 *)&bits,
					sizeof(bits), 112);
		kernel_neon_end();
	}

	/* Store state in digest */
	for (i = 0; i < 8; i++)
		dst[i] = cpu_to_be64(sctx->state[i]);

	/* Wipe context */
	memset(sctx, 0, sizeof(*sctx));

	return 0;
}

static int sha512_neon_export(struct shash_desc *desc, void *out)
{
	struct sha512_state *sctx = shash_desc_ctx(desc);

	memcpy(out, sctx, sizeof(*sctx));

	return 0;
}

static int sha512_neon_import(struct shash_desc *desc, const void *in)
{
	struct sha512_state *sctx = shash_desc_ctx(desc);

	memcpy(sctx, in, sizeof(*sctx));

	return 0;
}

static int sha384_neon_init(struct shash_desc *desc)
{
	struct sha512_state *sctx = shash_desc_ctx(desc);

	sctx->state[0] = SHA384_H0;
	sctx->state[1] = SHA384_H1;
	sctx->state[2] = SHA384_H2;
	sctx->state[3] = SHA384_H3;
	sctx->state[4] = SHA384_H4;
	sctx->state[5] = SHA384_H5;
	sctx->state[6] = SHA384_H6;
	sctx->state[7] = SHA384_H7;

	sctx->count[0] = sctx->count[1] = 0;

	return 0;
}

static int sha384_neon_final(struct shash_desc *desc, u8 *hash)
{
	u8 D[SHA512_DIGEST_SIZE];

	sha512_neon_final(desc, D);

	memcpy(hash, D, SHA384_DIGEST_SIZE);
	memzero_explicit(D, SHA512_DIGEST_SIZE);

	return 0;
}

static struct shash_alg algs[] = { {
	.digestsize	=	SHA512_DIGEST_SIZE,
	.init		=	sha512_neon_init,
	.update		=	sha512_neon_update,
	.final		=	sha512_neon_final,
	.export		=	sha512_neon_export,
	.import		=	sha512_neon_import,
	.descsize	=	sizeof(struct sha512_state),
	.statesize	=	sizeof(struct sha512_state),
	.base		=	{
		.cra_name	=	"sha512",
		.cra_driver_name =	"sha512-neon",
		.cra_priority	=	250,
		.cra_flags	=	CRYPTO_ALG_TYPE_SHASH,
		.cra_blocksize	=	SHA512_BLOCK_SIZE,
		.cra_module	=	THIS_MODULE,
	}
},  {
	.digestsize	=	SHA384_DIGEST_SIZE,
	.init		=	sha384_neon_init,
	.update		=	sha512_neon_update,
	.final		=	sha384_neon_final,
	.export		=	sha512_neon_export,
	.import		=	sha512_neon_import,
	.descsize	=	sizeof(struct sha512_state),
	.statesize	=	sizeof(struct sha512_state),
	.base		=	{
		.cra_name	=	"sha384",
		.cra_driver_name =	"sha384-neon",
		.cra_priority	=	250,
		.cra_flags	=	CRYPTO_ALG_TYPE_SHASH,
		.cra_blocksize	=	SHA384_BLOCK_SIZE,
		.cra_module	=	THIS_MODULE,
	}
} };

static int __init sha512_neon_mod_init(void)
{
	if (!cpu_has_neon())
		return -ENODEV;

	return crypto_register_shashes(algs, ARRAY_SIZE(algs));
}

static void __exit sha512_neon_mod_fini(void)
{
	crypto_unregister_shashes(algs, ARRAY_SIZE(algs));
}

module_init(sha512_neon_mod_init);
module_exit(sha512_neon_mod_fini);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("SHA512 Secure Hash Algorithm, NEON accelerated");

MODULE_ALIAS_CRYPTO("sha512");
MODULE_ALIAS_CRYPTO("sha384");