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/*
 * Shared crypto simd helpers
 *
 * Copyright (c) 2012 Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
 * Copyright (c) 2016 Herbert Xu <herbert@gondor.apana.org.au>
 *
 * Based on aesni-intel_glue.c by:
 *  Copyright (C) 2008, Intel Corp.
 *    Author: Huang Ying <ying.huang@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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 * USA
 *
 */

#include <crypto/cryptd.h>
#include <crypto/internal/simd.h>
#include <crypto/internal/skcipher.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/preempt.h>
#include <asm/simd.h>

struct simd_skcipher_alg {
	const char *ialg_name;
	struct skcipher_alg alg;
};

struct simd_skcipher_ctx {
	struct cryptd_skcipher *cryptd_tfm;
};

static int simd_skcipher_setkey(struct crypto_skcipher *tfm, const u8 *key,
				unsigned int key_len)
{
	struct simd_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct crypto_skcipher *child = &ctx->cryptd_tfm->base;
	int err;

	crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
	crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(tfm) &
					 CRYPTO_TFM_REQ_MASK);
	err = crypto_skcipher_setkey(child, key, key_len);
	crypto_skcipher_set_flags(tfm, crypto_skcipher_get_flags(child) &
				       CRYPTO_TFM_RES_MASK);
	return err;
}

static int simd_skcipher_encrypt(struct skcipher_request *req)
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct simd_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct skcipher_request *subreq;
	struct crypto_skcipher *child;

	subreq = skcipher_request_ctx(req);
	*subreq = *req;

	if (!may_use_simd() ||
	    (in_atomic() && cryptd_skcipher_queued(ctx->cryptd_tfm)))
		child = &ctx->cryptd_tfm->base;
	else
		child = cryptd_skcipher_child(ctx->cryptd_tfm);

	skcipher_request_set_tfm(subreq, child);

	return crypto_skcipher_encrypt(subreq);
}

static int simd_skcipher_decrypt(struct skcipher_request *req)
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct simd_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct skcipher_request *subreq;
	struct crypto_skcipher *child;

	subreq = skcipher_request_ctx(req);
	*subreq = *req;

	if (!may_use_simd() ||
	    (in_atomic() && cryptd_skcipher_queued(ctx->cryptd_tfm)))
		child = &ctx->cryptd_tfm->base;
	else
		child = cryptd_skcipher_child(ctx->cryptd_tfm);

	skcipher_request_set_tfm(subreq, child);

	return crypto_skcipher_decrypt(subreq);
}

static void simd_skcipher_exit(struct crypto_skcipher *tfm)
{
	struct simd_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);

	cryptd_free_skcipher(ctx->cryptd_tfm);
}

static int simd_skcipher_init(struct crypto_skcipher *tfm)
{
	struct simd_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct cryptd_skcipher *cryptd_tfm;
	struct simd_skcipher_alg *salg;
	struct skcipher_alg *alg;
	unsigned reqsize;

	alg = crypto_skcipher_alg(tfm);
	salg = container_of(alg, struct simd_skcipher_alg, alg);

	cryptd_tfm = cryptd_alloc_skcipher(salg->ialg_name,
					   CRYPTO_ALG_INTERNAL,
					   CRYPTO_ALG_INTERNAL);
	if (IS_ERR(cryptd_tfm))
		return PTR_ERR(cryptd_tfm);

	ctx->cryptd_tfm = cryptd_tfm;

	reqsize = sizeof(struct skcipher_request);
	reqsize += crypto_skcipher_reqsize(&cryptd_tfm->base);

	crypto_skcipher_set_reqsize(tfm, reqsize);

	return 0;
}

struct simd_skcipher_alg *simd_skcipher_create_compat(const char *algname,
						      const char *drvname,
						      const char *basename)
{
	struct simd_skcipher_alg *salg;
	struct crypto_skcipher *tfm;
	struct skcipher_alg *ialg;
	struct skcipher_alg *alg;
	int err;

	tfm = crypto_alloc_skcipher(basename, CRYPTO_ALG_INTERNAL,
				    CRYPTO_ALG_INTERNAL | CRYPTO_ALG_ASYNC);
	if (IS_ERR(tfm))
		return ERR_CAST(tfm);

	ialg = crypto_skcipher_alg(tfm);

	salg = kzalloc(sizeof(*salg), GFP_KERNEL);
	if (!salg) {
		salg = ERR_PTR(-ENOMEM);
		goto out_put_tfm;
	}

	salg->ialg_name = basename;
	alg = &salg->alg;

	err = -ENAMETOOLONG;
	if (snprintf(alg->base.cra_name, CRYPTO_MAX_ALG_NAME, "%s", algname) >=
	    CRYPTO_MAX_ALG_NAME)
		goto out_free_salg;

	if (snprintf(alg->base.cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s",
		     drvname) >= CRYPTO_MAX_ALG_NAME)
		goto out_free_salg;

	alg->base.cra_flags = CRYPTO_ALG_ASYNC;
	alg->base.cra_priority = ialg->base.cra_priority;
	alg->base.cra_blocksize = ialg->base.cra_blocksize;
	alg->base.cra_alignmask = ialg->base.cra_alignmask;
	alg->base.cra_module = ialg->base.cra_module;
	alg->base.cra_ctxsize = sizeof(struct simd_skcipher_ctx);

	alg->ivsize = ialg->ivsize;
	alg->chunksize = ialg->chunksize;
	alg->min_keysize = ialg->min_keysize;
	alg->max_keysize = ialg->max_keysize;

	alg->init = simd_skcipher_init;
	alg->exit = simd_skcipher_exit;

	alg->setkey = simd_skcipher_setkey;
	alg->encrypt = simd_skcipher_encrypt;
	alg->decrypt = simd_skcipher_decrypt;

	err = crypto_register_skcipher(alg);
	if (err)
		goto out_free_salg;

out_put_tfm:
	crypto_free_skcipher(tfm);
	return salg;

out_free_salg:
	kfree(salg);
	salg = ERR_PTR(err);
	goto out_put_tfm;
}
EXPORT_SYMBOL_GPL(simd_skcipher_create_compat);

struct simd_skcipher_alg *simd_skcipher_create(const char *algname,
					       const char *basename)
{
	char drvname[CRYPTO_MAX_ALG_NAME];

	if (snprintf(drvname, CRYPTO_MAX_ALG_NAME, "simd-%s", basename) >=
	    CRYPTO_MAX_ALG_NAME)
		return ERR_PTR(-ENAMETOOLONG);

	return simd_skcipher_create_compat(algname, drvname, basename);
}
EXPORT_SYMBOL_GPL(simd_skcipher_create);

void simd_skcipher_free(struct simd_skcipher_alg *salg)
{
	crypto_unregister_skcipher(&salg->alg);
	kfree(salg);
}
EXPORT_SYMBOL_GPL(simd_skcipher_free);

MODULE_LICENSE("GPL");