// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Glue Code for SSE2 assembler versions of Serpent Cipher
 *
 * Copyright (c) 2011 Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
 *
 * Glue code based on aesni-intel_glue.c by:
 *  Copyright (C) 2008, Intel Corp.
 *    Author: Huang Ying <ying.huang@intel.com>
 *
 * CBC & ECB parts based on code (crypto/cbc.c,ecb.c) by:
 *   Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
 * CTR part based on code (crypto/ctr.c) by:
 *   (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com>
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/crypto.h>
#include <linux/err.h>
#include <crypto/algapi.h>
#include <crypto/b128ops.h>
#include <crypto/internal/simd.h>
#include <crypto/serpent.h>
#include <asm/crypto/serpent-sse2.h>
#include <asm/crypto/glue_helper.h>

static int serpent_setkey_skcipher(struct crypto_skcipher *tfm,
				   const u8 *key, unsigned int keylen)
{
	return __serpent_setkey(crypto_skcipher_ctx(tfm), key, keylen);
}

static void serpent_decrypt_cbc_xway(const void *ctx, u8 *d, const u8 *s)
{
	u128 ivs[SERPENT_PARALLEL_BLOCKS - 1];
	u128 *dst = (u128 *)d;
	const u128 *src = (const u128 *)s;
	unsigned int j;

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

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

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

static void serpent_crypt_ctr(const void *ctx, u8 *d, const u8 *s, le128 *iv)
{
	be128 ctrblk;
	u128 *dst = (u128 *)d;
	const u128 *src = (const u128 *)s;

	le128_to_be128(&ctrblk, iv);
	le128_inc(iv);

	__serpent_encrypt(ctx, (u8 *)&ctrblk, (u8 *)&ctrblk);
	u128_xor(dst, src, (u128 *)&ctrblk);
}

static void serpent_crypt_ctr_xway(const void *ctx, u8 *d, const u8 *s,
				   le128 *iv)
{
	be128 ctrblks[SERPENT_PARALLEL_BLOCKS];
	u128 *dst = (u128 *)d;
	const u128 *src = (const u128 *)s;
	unsigned int i;

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

		le128_to_be128(&ctrblks[i], iv);
		le128_inc(iv);
	}

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

static const struct common_glue_ctx serpent_enc = {
	.num_funcs = 2,
	.fpu_blocks_limit = SERPENT_PARALLEL_BLOCKS,

	.funcs = { {
		.num_blocks = SERPENT_PARALLEL_BLOCKS,
		.fn_u = { .ecb = serpent_enc_blk_xway }
	}, {
		.num_blocks = 1,
		.fn_u = { .ecb = __serpent_encrypt }
	} }
};

static const struct common_glue_ctx serpent_ctr = {
	.num_funcs = 2,
	.fpu_blocks_limit = SERPENT_PARALLEL_BLOCKS,

	.funcs = { {
		.num_blocks = SERPENT_PARALLEL_BLOCKS,
		.fn_u = { .ctr = serpent_crypt_ctr_xway }
	}, {
		.num_blocks = 1,
		.fn_u = { .ctr = serpent_crypt_ctr }
	} }
};

static const struct common_glue_ctx serpent_dec = {
	.num_funcs = 2,
	.fpu_blocks_limit = SERPENT_PARALLEL_BLOCKS,

	.funcs = { {
		.num_blocks = SERPENT_PARALLEL_BLOCKS,
		.fn_u = { .ecb = serpent_dec_blk_xway }
	}, {
		.num_blocks = 1,
		.fn_u = { .ecb = __serpent_decrypt }
	} }
};

static const struct common_glue_ctx serpent_dec_cbc = {
	.num_funcs = 2,
	.fpu_blocks_limit = SERPENT_PARALLEL_BLOCKS,

	.funcs = { {
		.num_blocks = SERPENT_PARALLEL_BLOCKS,
		.fn_u = { .cbc = serpent_decrypt_cbc_xway }
	}, {
		.num_blocks = 1,
		.fn_u = { .cbc = __serpent_decrypt }
	} }
};

static int ecb_encrypt(struct skcipher_request *req)
{
	return glue_ecb_req_128bit(&serpent_enc, req);
}

static int ecb_decrypt(struct skcipher_request *req)
{
	return glue_ecb_req_128bit(&serpent_dec, req);
}

static int cbc_encrypt(struct skcipher_request *req)
{
	return glue_cbc_encrypt_req_128bit(__serpent_encrypt,
					   req);
}

static int cbc_decrypt(struct skcipher_request *req)
{
	return glue_cbc_decrypt_req_128bit(&serpent_dec_cbc, req);
}

static int ctr_crypt(struct skcipher_request *req)
{
	return glue_ctr_req_128bit(&serpent_ctr, req);
}

static struct skcipher_alg serpent_algs[] = {
	{
		.base.cra_name		= "__ecb(serpent)",
		.base.cra_driver_name	= "__ecb-serpent-sse2",
		.base.cra_priority	= 400,
		.base.cra_flags		= CRYPTO_ALG_INTERNAL,
		.base.cra_blocksize	= SERPENT_BLOCK_SIZE,
		.base.cra_ctxsize	= sizeof(struct serpent_ctx),
		.base.cra_module	= THIS_MODULE,
		.min_keysize		= SERPENT_MIN_KEY_SIZE,
		.max_keysize		= SERPENT_MAX_KEY_SIZE,
		.setkey			= serpent_setkey_skcipher,
		.encrypt		= ecb_encrypt,
		.decrypt		= ecb_decrypt,
	}, {
		.base.cra_name		= "__cbc(serpent)",
		.base.cra_driver_name	= "__cbc-serpent-sse2",
		.base.cra_priority	= 400,
		.base.cra_flags		= CRYPTO_ALG_INTERNAL,
		.base.cra_blocksize	= SERPENT_BLOCK_SIZE,
		.base.cra_ctxsize	= sizeof(struct serpent_ctx),
		.base.cra_module	= THIS_MODULE,
		.min_keysize		= SERPENT_MIN_KEY_SIZE,
		.max_keysize		= SERPENT_MAX_KEY_SIZE,
		.ivsize			= SERPENT_BLOCK_SIZE,
		.setkey			= serpent_setkey_skcipher,
		.encrypt		= cbc_encrypt,
		.decrypt		= cbc_decrypt,
	}, {
		.base.cra_name		= "__ctr(serpent)",
		.base.cra_driver_name	= "__ctr-serpent-sse2",
		.base.cra_priority	= 400,
		.base.cra_flags		= CRYPTO_ALG_INTERNAL,
		.base.cra_blocksize	= 1,
		.base.cra_ctxsize	= sizeof(struct serpent_ctx),
		.base.cra_module	= THIS_MODULE,
		.min_keysize		= SERPENT_MIN_KEY_SIZE,
		.max_keysize		= SERPENT_MAX_KEY_SIZE,
		.ivsize			= SERPENT_BLOCK_SIZE,
		.chunksize		= SERPENT_BLOCK_SIZE,
		.setkey			= serpent_setkey_skcipher,
		.encrypt		= ctr_crypt,
		.decrypt		= ctr_crypt,
	},
};

static struct simd_skcipher_alg *serpent_simd_algs[ARRAY_SIZE(serpent_algs)];

static int __init serpent_sse2_init(void)
{
	if (!boot_cpu_has(X86_FEATURE_XMM2)) {
		printk(KERN_INFO "SSE2 instructions are not detected.\n");
		return -ENODEV;
	}

	return simd_register_skciphers_compat(serpent_algs,
					      ARRAY_SIZE(serpent_algs),
					      serpent_simd_algs);
}

static void __exit serpent_sse2_exit(void)
{
	simd_unregister_skciphers(serpent_algs, ARRAY_SIZE(serpent_algs),
				  serpent_simd_algs);
}

module_init(serpent_sse2_init);
module_exit(serpent_sse2_exit);

MODULE_DESCRIPTION("Serpent Cipher Algorithm, SSE2 optimized");
MODULE_LICENSE("GPL");
MODULE_ALIAS_CRYPTO("serpent");