/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * SM4 Cipher Algorithm, AES-NI/AVX optimized.
 * as specified in
 * https://tools.ietf.org/id/draft-ribose-cfrg-sm4-10.html
 *
 * Copyright (c) 2021, Alibaba Group.
 * Copyright (c) 2021 Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
 */

#include <linux/module.h>
#include <linux/crypto.h>
#include <linux/kernel.h>
#include <asm/simd.h>
#include <crypto/internal/simd.h>
#include <crypto/internal/skcipher.h>
#include <crypto/sm4.h>
#include "sm4-avx.h"

#define SM4_CRYPT8_BLOCK_SIZE	(SM4_BLOCK_SIZE * 8)

asmlinkage void sm4_aesni_avx_crypt4(const u32 *rk, u8 *dst,
				const u8 *src, int nblocks);
asmlinkage void sm4_aesni_avx_crypt8(const u32 *rk, u8 *dst,
				const u8 *src, int nblocks);
asmlinkage void sm4_aesni_avx_ctr_enc_blk8(const u32 *rk, u8 *dst,
				const u8 *src, u8 *iv);
asmlinkage void sm4_aesni_avx_cbc_dec_blk8(const u32 *rk, u8 *dst,
				const u8 *src, u8 *iv);

static int sm4_skcipher_setkey(struct crypto_skcipher *tfm, const u8 *key,
			unsigned int key_len)
{
	struct sm4_ctx *ctx = crypto_skcipher_ctx(tfm);

	return sm4_expandkey(ctx, key, key_len);
}

static int ecb_do_crypt(struct skcipher_request *req, const u32 *rkey)
{
	struct skcipher_walk walk;
	unsigned int nbytes;
	int err;

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

	while ((nbytes = walk.nbytes) > 0) {
		const u8 *src = walk.src.virt.addr;
		u8 *dst = walk.dst.virt.addr;

		kernel_fpu_begin();
		while (nbytes >= SM4_CRYPT8_BLOCK_SIZE) {
			sm4_aesni_avx_crypt8(rkey, dst, src, 8);
			dst += SM4_CRYPT8_BLOCK_SIZE;
			src += SM4_CRYPT8_BLOCK_SIZE;
			nbytes -= SM4_CRYPT8_BLOCK_SIZE;
		}
		while (nbytes >= SM4_BLOCK_SIZE) {
			unsigned int nblocks = min(nbytes >> 4, 4u);
			sm4_aesni_avx_crypt4(rkey, dst, src, nblocks);
			dst += nblocks * SM4_BLOCK_SIZE;
			src += nblocks * SM4_BLOCK_SIZE;
			nbytes -= nblocks * SM4_BLOCK_SIZE;
		}
		kernel_fpu_end();

		err = skcipher_walk_done(&walk, nbytes);
	}

	return err;
}

int sm4_avx_ecb_encrypt(struct skcipher_request *req)
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct sm4_ctx *ctx = crypto_skcipher_ctx(tfm);

	return ecb_do_crypt(req, ctx->rkey_enc);
}
EXPORT_SYMBOL_GPL(sm4_avx_ecb_encrypt);

int sm4_avx_ecb_decrypt(struct skcipher_request *req)
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct sm4_ctx *ctx = crypto_skcipher_ctx(tfm);

	return ecb_do_crypt(req, ctx->rkey_dec);
}
EXPORT_SYMBOL_GPL(sm4_avx_ecb_decrypt);

int sm4_cbc_encrypt(struct skcipher_request *req)
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct sm4_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct skcipher_walk walk;
	unsigned int nbytes;
	int err;

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

	while ((nbytes = walk.nbytes) > 0) {
		const u8 *iv = walk.iv;
		const u8 *src = walk.src.virt.addr;
		u8 *dst = walk.dst.virt.addr;

		while (nbytes >= SM4_BLOCK_SIZE) {
			crypto_xor_cpy(dst, src, iv, SM4_BLOCK_SIZE);
			sm4_crypt_block(ctx->rkey_enc, dst, dst);
			iv = dst;
			src += SM4_BLOCK_SIZE;
			dst += SM4_BLOCK_SIZE;
			nbytes -= SM4_BLOCK_SIZE;
		}
		if (iv != walk.iv)
			memcpy(walk.iv, iv, SM4_BLOCK_SIZE);

		err = skcipher_walk_done(&walk, nbytes);
	}

	return err;
}
EXPORT_SYMBOL_GPL(sm4_cbc_encrypt);

int sm4_avx_cbc_decrypt(struct skcipher_request *req,
			unsigned int bsize, sm4_crypt_func func)
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct sm4_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct skcipher_walk walk;
	unsigned int nbytes;
	int err;

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

	while ((nbytes = walk.nbytes) > 0) {
		const u8 *src = walk.src.virt.addr;
		u8 *dst = walk.dst.virt.addr;

		kernel_fpu_begin();

		while (nbytes >= bsize) {
			func(ctx->rkey_dec, dst, src, walk.iv);
			dst += bsize;
			src += bsize;
			nbytes -= bsize;
		}

		while (nbytes >= SM4_BLOCK_SIZE) {
			u8 keystream[SM4_BLOCK_SIZE * 8];
			u8 iv[SM4_BLOCK_SIZE];
			unsigned int nblocks = min(nbytes >> 4, 8u);
			int i;

			sm4_aesni_avx_crypt8(ctx->rkey_dec, keystream,
						src, nblocks);

			src += ((int)nblocks - 2) * SM4_BLOCK_SIZE;
			dst += (nblocks - 1) * SM4_BLOCK_SIZE;
			memcpy(iv, src + SM4_BLOCK_SIZE, SM4_BLOCK_SIZE);

			for (i = nblocks - 1; i > 0; i--) {
				crypto_xor_cpy(dst, src,
					&keystream[i * SM4_BLOCK_SIZE],
					SM4_BLOCK_SIZE);
				src -= SM4_BLOCK_SIZE;
				dst -= SM4_BLOCK_SIZE;
			}
			crypto_xor_cpy(dst, walk.iv, keystream, SM4_BLOCK_SIZE);
			memcpy(walk.iv, iv, SM4_BLOCK_SIZE);
			dst += nblocks * SM4_BLOCK_SIZE;
			src += (nblocks + 1) * SM4_BLOCK_SIZE;
			nbytes -= nblocks * SM4_BLOCK_SIZE;
		}

		kernel_fpu_end();
		err = skcipher_walk_done(&walk, nbytes);
	}

	return err;
}
EXPORT_SYMBOL_GPL(sm4_avx_cbc_decrypt);

static int cbc_decrypt(struct skcipher_request *req)
{
	return sm4_avx_cbc_decrypt(req, SM4_CRYPT8_BLOCK_SIZE,
				sm4_aesni_avx_cbc_dec_blk8);
}

int sm4_avx_ctr_crypt(struct skcipher_request *req,
			unsigned int bsize, sm4_crypt_func func)
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct sm4_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct skcipher_walk walk;
	unsigned int nbytes;
	int err;

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

	while ((nbytes = walk.nbytes) > 0) {
		const u8 *src = walk.src.virt.addr;
		u8 *dst = walk.dst.virt.addr;

		kernel_fpu_begin();

		while (nbytes >= bsize) {
			func(ctx->rkey_enc, dst, src, walk.iv);
			dst += bsize;
			src += bsize;
			nbytes -= bsize;
		}

		while (nbytes >= SM4_BLOCK_SIZE) {
			u8 keystream[SM4_BLOCK_SIZE * 8];
			unsigned int nblocks = min(nbytes >> 4, 8u);
			int i;

			for (i = 0; i < nblocks; i++) {
				memcpy(&keystream[i * SM4_BLOCK_SIZE],
					walk.iv, SM4_BLOCK_SIZE);
				crypto_inc(walk.iv, SM4_BLOCK_SIZE);
			}
			sm4_aesni_avx_crypt8(ctx->rkey_enc, keystream,
					keystream, nblocks);

			crypto_xor_cpy(dst, src, keystream,
					nblocks * SM4_BLOCK_SIZE);
			dst += nblocks * SM4_BLOCK_SIZE;
			src += nblocks * SM4_BLOCK_SIZE;
			nbytes -= nblocks * SM4_BLOCK_SIZE;
		}

		kernel_fpu_end();

		/* tail */
		if (walk.nbytes == walk.total && nbytes > 0) {
			u8 keystream[SM4_BLOCK_SIZE];

			memcpy(keystream, walk.iv, SM4_BLOCK_SIZE);
			crypto_inc(walk.iv, SM4_BLOCK_SIZE);

			sm4_crypt_block(ctx->rkey_enc, keystream, keystream);

			crypto_xor_cpy(dst, src, keystream, nbytes);
			dst += nbytes;
			src += nbytes;
			nbytes = 0;
		}

		err = skcipher_walk_done(&walk, nbytes);
	}

	return err;
}
EXPORT_SYMBOL_GPL(sm4_avx_ctr_crypt);

static int ctr_crypt(struct skcipher_request *req)
{
	return sm4_avx_ctr_crypt(req, SM4_CRYPT8_BLOCK_SIZE,
				sm4_aesni_avx_ctr_enc_blk8);
}

static struct skcipher_alg sm4_aesni_avx_skciphers[] = {
	{
		.base = {
			.cra_name		= "__ecb(sm4)",
			.cra_driver_name	= "__ecb-sm4-aesni-avx",
			.cra_priority		= 400,
			.cra_flags		= CRYPTO_ALG_INTERNAL,
			.cra_blocksize		= SM4_BLOCK_SIZE,
			.cra_ctxsize		= sizeof(struct sm4_ctx),
			.cra_module		= THIS_MODULE,
		},
		.min_keysize	= SM4_KEY_SIZE,
		.max_keysize	= SM4_KEY_SIZE,
		.walksize	= 8 * SM4_BLOCK_SIZE,
		.setkey		= sm4_skcipher_setkey,
		.encrypt	= sm4_avx_ecb_encrypt,
		.decrypt	= sm4_avx_ecb_decrypt,
	}, {
		.base = {
			.cra_name		= "__cbc(sm4)",
			.cra_driver_name	= "__cbc-sm4-aesni-avx",
			.cra_priority		= 400,
			.cra_flags		= CRYPTO_ALG_INTERNAL,
			.cra_blocksize		= SM4_BLOCK_SIZE,
			.cra_ctxsize		= sizeof(struct sm4_ctx),
			.cra_module		= THIS_MODULE,
		},
		.min_keysize	= SM4_KEY_SIZE,
		.max_keysize	= SM4_KEY_SIZE,
		.ivsize		= SM4_BLOCK_SIZE,
		.walksize	= 8 * SM4_BLOCK_SIZE,
		.setkey		= sm4_skcipher_setkey,
		.encrypt	= sm4_cbc_encrypt,
		.decrypt	= cbc_decrypt,
	}, {
		.base = {
			.cra_name		= "__ctr(sm4)",
			.cra_driver_name	= "__ctr-sm4-aesni-avx",
			.cra_priority		= 400,
			.cra_flags		= CRYPTO_ALG_INTERNAL,
			.cra_blocksize		= 1,
			.cra_ctxsize		= sizeof(struct sm4_ctx),
			.cra_module		= THIS_MODULE,
		},
		.min_keysize	= SM4_KEY_SIZE,
		.max_keysize	= SM4_KEY_SIZE,
		.ivsize		= SM4_BLOCK_SIZE,
		.chunksize	= SM4_BLOCK_SIZE,
		.walksize	= 8 * SM4_BLOCK_SIZE,
		.setkey		= sm4_skcipher_setkey,
		.encrypt	= ctr_crypt,
		.decrypt	= ctr_crypt,
	}
};

static struct simd_skcipher_alg *
simd_sm4_aesni_avx_skciphers[ARRAY_SIZE(sm4_aesni_avx_skciphers)];

static int __init sm4_init(void)
{
	const char *feature_name;

	if (!boot_cpu_has(X86_FEATURE_AVX) ||
	    !boot_cpu_has(X86_FEATURE_AES) ||
	    !boot_cpu_has(X86_FEATURE_OSXSAVE)) {
		pr_info("AVX or AES-NI instructions are not detected.\n");
		return -ENODEV;
	}

	if (!cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM,
				&feature_name)) {
		pr_info("CPU feature '%s' is not supported.\n", feature_name);
		return -ENODEV;
	}

	return simd_register_skciphers_compat(sm4_aesni_avx_skciphers,
					ARRAY_SIZE(sm4_aesni_avx_skciphers),
					simd_sm4_aesni_avx_skciphers);
}

static void __exit sm4_exit(void)
{
	simd_unregister_skciphers(sm4_aesni_avx_skciphers,
					ARRAY_SIZE(sm4_aesni_avx_skciphers),
					simd_sm4_aesni_avx_skciphers);
}

module_init(sm4_init);
module_exit(sm4_exit);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Tianjia Zhang <tianjia.zhang@linux.alibaba.com>");
MODULE_DESCRIPTION("SM4 Cipher Algorithm, AES-NI/AVX optimized");
MODULE_ALIAS_CRYPTO("sm4");
MODULE_ALIAS_CRYPTO("sm4-aesni-avx");