// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Shared glue code for 128bit block ciphers
 *
 * Copyright © 2012-2013 Jussi Kivilinna <jussi.kivilinna@iki.fi>
 *
 * 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 <crypto/b128ops.h>
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include <asm/crypto/glue_helper.h>

int glue_ecb_req_128bit(const struct common_glue_ctx *gctx,
			struct skcipher_request *req)
{
	void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
	const unsigned int bsize = 128 / 8;
	struct skcipher_walk walk;
	bool fpu_enabled = false;
	unsigned int nbytes;
	int err;

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

	while ((nbytes = walk.nbytes)) {
		const u8 *src = walk.src.virt.addr;
		u8 *dst = walk.dst.virt.addr;
		unsigned int func_bytes;
		unsigned int i;

		fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
					     &walk, fpu_enabled, nbytes);
		for (i = 0; i < gctx->num_funcs; i++) {
			func_bytes = bsize * gctx->funcs[i].num_blocks;

			if (nbytes < func_bytes)
				continue;

			/* Process multi-block batch */
			do {
				gctx->funcs[i].fn_u.ecb(ctx, dst, src);
				src += func_bytes;
				dst += func_bytes;
				nbytes -= func_bytes;
			} while (nbytes >= func_bytes);

			if (nbytes < bsize)
				break;
		}
		err = skcipher_walk_done(&walk, nbytes);
	}

	glue_fpu_end(fpu_enabled);
	return err;
}
EXPORT_SYMBOL_GPL(glue_ecb_req_128bit);

int glue_cbc_encrypt_req_128bit(const common_glue_func_t fn,
				struct skcipher_request *req)
{
	void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
	const unsigned int bsize = 128 / 8;
	struct skcipher_walk walk;
	unsigned int nbytes;
	int err;

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

	while ((nbytes = walk.nbytes)) {
		const u128 *src = (u128 *)walk.src.virt.addr;
		u128 *dst = (u128 *)walk.dst.virt.addr;
		u128 *iv = (u128 *)walk.iv;

		do {
			u128_xor(dst, src, iv);
			fn(ctx, (u8 *)dst, (u8 *)dst);
			iv = dst;
			src++;
			dst++;
			nbytes -= bsize;
		} while (nbytes >= bsize);

		*(u128 *)walk.iv = *iv;
		err = skcipher_walk_done(&walk, nbytes);
	}
	return err;
}
EXPORT_SYMBOL_GPL(glue_cbc_encrypt_req_128bit);

int glue_cbc_decrypt_req_128bit(const struct common_glue_ctx *gctx,
				struct skcipher_request *req)
{
	void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
	const unsigned int bsize = 128 / 8;
	struct skcipher_walk walk;
	bool fpu_enabled = false;
	unsigned int nbytes;
	int err;

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

	while ((nbytes = walk.nbytes)) {
		const u128 *src = walk.src.virt.addr;
		u128 *dst = walk.dst.virt.addr;
		unsigned int func_bytes, num_blocks;
		unsigned int i;
		u128 last_iv;

		fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
					     &walk, fpu_enabled, nbytes);
		/* Start of the last block. */
		src += nbytes / bsize - 1;
		dst += nbytes / bsize - 1;

		last_iv = *src;

		for (i = 0; i < gctx->num_funcs; i++) {
			num_blocks = gctx->funcs[i].num_blocks;
			func_bytes = bsize * num_blocks;

			if (nbytes < func_bytes)
				continue;

			/* Process multi-block batch */
			do {
				src -= num_blocks - 1;
				dst -= num_blocks - 1;

				gctx->funcs[i].fn_u.cbc(ctx, (u8 *)dst,
							(const u8 *)src);

				nbytes -= func_bytes;
				if (nbytes < bsize)
					goto done;

				u128_xor(dst, dst, --src);
				dst--;
			} while (nbytes >= func_bytes);
		}
done:
		u128_xor(dst, dst, (u128 *)walk.iv);
		*(u128 *)walk.iv = last_iv;
		err = skcipher_walk_done(&walk, nbytes);
	}

	glue_fpu_end(fpu_enabled);
	return err;
}
EXPORT_SYMBOL_GPL(glue_cbc_decrypt_req_128bit);

MODULE_LICENSE("GPL");