// 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>
 */

#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/serpent.h>

#include "serpent-sse2.h"
#include "ecb_cbc_helpers.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 *dst, const u8 *src)
{
        u8 buf[SERPENT_PARALLEL_BLOCKS - 1][SERPENT_BLOCK_SIZE];
        const u8 *s = src;

        if (dst == src)
                s = memcpy(buf, src, sizeof(buf));
        serpent_dec_blk_xway(ctx, dst, src);
        crypto_xor(dst + SERPENT_BLOCK_SIZE, s, sizeof(buf));
}

static int ecb_encrypt(struct skcipher_request *req)
{
        ECB_WALK_START(req, SERPENT_BLOCK_SIZE, SERPENT_PARALLEL_BLOCKS);
        ECB_BLOCK(SERPENT_PARALLEL_BLOCKS, serpent_enc_blk_xway);
        ECB_BLOCK(1, __serpent_encrypt);
        ECB_WALK_END();
}

static int ecb_decrypt(struct skcipher_request *req)
{
        ECB_WALK_START(req, SERPENT_BLOCK_SIZE, SERPENT_PARALLEL_BLOCKS);
        ECB_BLOCK(SERPENT_PARALLEL_BLOCKS, serpent_dec_blk_xway);
        ECB_BLOCK(1, __serpent_decrypt);
        ECB_WALK_END();
}

static int cbc_encrypt(struct skcipher_request *req)
{
        CBC_WALK_START(req, SERPENT_BLOCK_SIZE, -1);
        CBC_ENC_BLOCK(__serpent_encrypt);
        CBC_WALK_END();
}

static int cbc_decrypt(struct skcipher_request *req)
{
        CBC_WALK_START(req, SERPENT_BLOCK_SIZE, SERPENT_PARALLEL_BLOCKS);
        CBC_DEC_BLOCK(SERPENT_PARALLEL_BLOCKS, serpent_decrypt_cbc_xway);
        CBC_DEC_BLOCK(1, __serpent_decrypt);
        CBC_WALK_END();
}

static struct skcipher_alg serpent_algs[] = {
        {
                .base.cra_name          = "ecb(serpent)",
                .base.cra_driver_name   = "ecb-serpent-sse2",
                .base.cra_priority      = 400,
                .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_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,
        },
};

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 crypto_register_skciphers(serpent_algs,
                                         ARRAY_SIZE(serpent_algs));
}

static void __exit serpent_sse2_exit(void)
{
        crypto_unregister_skciphers(serpent_algs, ARRAY_SIZE(serpent_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");