[linux-2.6-block.git] / drivers / crypto / vmx / aes_ctr.c

/**
 * AES CTR routines supporting VMX instructions on the Power 8
 *
 * Copyright (C) 2015 International Business Machines Inc.
 *
 * 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; version 2 only.
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * Author: Marcelo Henrique Cerri <mhcerri@br.ibm.com>
 */

#include <linux/types.h>
#include <linux/err.h>
#include <linux/crypto.h>
#include <linux/delay.h>
#include <linux/hardirq.h>
#include <asm/switch_to.h>
#include <crypto/aes.h>
#include <crypto/scatterwalk.h>
#include "aesp8-ppc.h"

struct p8_aes_ctr_ctx {
	struct crypto_blkcipher *fallback;
	struct aes_key enc_key;
};

static int p8_aes_ctr_init(struct crypto_tfm *tfm)
{
	const char *alg;
	struct crypto_blkcipher *fallback;
	struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm);

	if (!(alg = crypto_tfm_alg_name(tfm))) {
		printk(KERN_ERR "Failed to get algorithm name.\n");
		return -ENOENT;
	}

	fallback =
	    crypto_alloc_blkcipher(alg, 0, CRYPTO_ALG_NEED_FALLBACK);
	if (IS_ERR(fallback)) {
		printk(KERN_ERR
		       "Failed to allocate transformation for '%s': %ld\n",
		       alg, PTR_ERR(fallback));
		return PTR_ERR(fallback);
	}
	printk(KERN_INFO "Using '%s' as fallback implementation.\n",
	       crypto_tfm_alg_driver_name((struct crypto_tfm *) fallback));

	crypto_blkcipher_set_flags(
		fallback,
		crypto_blkcipher_get_flags((struct crypto_blkcipher *)tfm));
	ctx->fallback = fallback;

	return 0;
}

static void p8_aes_ctr_exit(struct crypto_tfm *tfm)
{
	struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm);

	if (ctx->fallback) {
		crypto_free_blkcipher(ctx->fallback);
		ctx->fallback = NULL;
	}
}

static int p8_aes_ctr_setkey(struct crypto_tfm *tfm, const u8 *key,
			     unsigned int keylen)
{
	int ret;
	struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm);

	pagefault_disable();
	enable_kernel_altivec();
	ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key);
	pagefault_enable();

	ret += crypto_blkcipher_setkey(ctx->fallback, key, keylen);
	return ret;
}

static void p8_aes_ctr_final(struct p8_aes_ctr_ctx *ctx,
			     struct blkcipher_walk *walk)
{
	u8 *ctrblk = walk->iv;
	u8 keystream[AES_BLOCK_SIZE];
	u8 *src = walk->src.virt.addr;
	u8 *dst = walk->dst.virt.addr;
	unsigned int nbytes = walk->nbytes;

	pagefault_disable();
	enable_kernel_altivec();
	aes_p8_encrypt(ctrblk, keystream, &ctx->enc_key);
	pagefault_enable();

	crypto_xor(keystream, src, nbytes);
	memcpy(dst, keystream, nbytes);
	crypto_inc(ctrblk, AES_BLOCK_SIZE);
}

static int p8_aes_ctr_crypt(struct blkcipher_desc *desc,
			    struct scatterlist *dst,
			    struct scatterlist *src, unsigned int nbytes)
{
	int ret;
	struct blkcipher_walk walk;
	struct p8_aes_ctr_ctx *ctx =
		crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm));
	struct blkcipher_desc fallback_desc = {
		.tfm = ctx->fallback,
		.info = desc->info,
		.flags = desc->flags
	};

	if (in_interrupt()) {
		ret = crypto_blkcipher_encrypt(&fallback_desc, dst, src,
					       nbytes);
	} else {
		blkcipher_walk_init(&walk, dst, src, nbytes);
		ret = blkcipher_walk_virt_block(desc, &walk, AES_BLOCK_SIZE);
		while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) {
			pagefault_disable();
			enable_kernel_altivec();
			aes_p8_ctr32_encrypt_blocks(walk.src.virt.addr,
						    walk.dst.virt.addr,
						    (nbytes &
						     AES_BLOCK_MASK) /
						    AES_BLOCK_SIZE,
						    &ctx->enc_key,
						    walk.iv);
			pagefault_enable();

			crypto_inc(walk.iv, AES_BLOCK_SIZE);
			nbytes &= AES_BLOCK_SIZE - 1;
			ret = blkcipher_walk_done(desc, &walk, nbytes);
		}
		if (walk.nbytes) {
			p8_aes_ctr_final(ctx, &walk);
			ret = blkcipher_walk_done(desc, &walk, 0);
		}
	}

	return ret;
}

struct crypto_alg p8_aes_ctr_alg = {
	.cra_name = "ctr(aes)",
	.cra_driver_name = "p8_aes_ctr",
	.cra_module = THIS_MODULE,
	.cra_priority = 1000,
	.cra_type = &crypto_blkcipher_type,
	.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK,
	.cra_alignmask = 0,
	.cra_blocksize = 1,
	.cra_ctxsize = sizeof(struct p8_aes_ctr_ctx),
	.cra_init = p8_aes_ctr_init,
	.cra_exit = p8_aes_ctr_exit,
	.cra_blkcipher = {
			  .ivsize = 0,
			  .min_keysize = AES_MIN_KEY_SIZE,
			  .max_keysize = AES_MAX_KEY_SIZE,
			  .setkey = p8_aes_ctr_setkey,
			  .encrypt = p8_aes_ctr_crypt,
			  .decrypt = p8_aes_ctr_crypt,
	},
};
Commit	Line	Data
4f7f60d3 MC	1	/**
	2	* AES CTR routines supporting VMX instructions on the Power 8
	3	*
	4	* Copyright (C) 2015 International Business Machines Inc.
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; version 2 only.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program; if not, write to the Free Software
	17	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	18	*
	19	* Author: Marcelo Henrique Cerri <mhcerri@br.ibm.com>
	20	*/
	21
	22	#include <linux/types.h>
	23	#include <linux/err.h>
	24	#include <linux/crypto.h>
	25	#include <linux/delay.h>
	26	#include <linux/hardirq.h>
	27	#include <asm/switch_to.h>
	28	#include <crypto/aes.h>
	29	#include <crypto/scatterwalk.h>
	30	#include "aesp8-ppc.h"
	31
	32	struct p8_aes_ctr_ctx {
4beb1060 HX	33	struct crypto_blkcipher *fallback;
4beb1060 HX	34	struct aes_key enc_key;
4f7f60d3 MC	35	};
	36
	37	static int p8_aes_ctr_init(struct crypto_tfm *tfm)
	38	{
4beb1060 HX	39	const char *alg;
	40	struct crypto_blkcipher *fallback;
	41	struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
	42
	43	if (!(alg = crypto_tfm_alg_name(tfm))) {
	44	printk(KERN_ERR "Failed to get algorithm name.\n");
	45	return -ENOENT;
	46	}
	47
	48	fallback =
	49	crypto_alloc_blkcipher(alg, 0, CRYPTO_ALG_NEED_FALLBACK);
	50	if (IS_ERR(fallback)) {
	51	printk(KERN_ERR
	52	"Failed to allocate transformation for '%s': %ld\n",
	53	alg, PTR_ERR(fallback));
	54	return PTR_ERR(fallback);
	55	}
	56	printk(KERN_INFO "Using '%s' as fallback implementation.\n",
	57	crypto_tfm_alg_driver_name((struct crypto_tfm *) fallback));
	58
	59	crypto_blkcipher_set_flags(
	60	fallback,
	61	crypto_blkcipher_get_flags((struct crypto_blkcipher *)tfm));
	62	ctx->fallback = fallback;
	63
	64	return 0;
4f7f60d3 MC	65	}
	66
	67	static void p8_aes_ctr_exit(struct crypto_tfm *tfm)
	68	{
4beb1060	69	struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
4f7f60d3	70
4beb1060 HX	71	if (ctx->fallback) {
	72	crypto_free_blkcipher(ctx->fallback);
	73	ctx->fallback = NULL;
	74	}
4f7f60d3 MC	75	}
	76
	77	static int p8_aes_ctr_setkey(struct crypto_tfm tfm, const u8 key,
4beb1060	78	unsigned int keylen)
4f7f60d3	79	{
4beb1060 HX	80	int ret;
4beb1060 HX	81	struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
4f7f60d3	82
4beb1060 HX	83	pagefault_disable();
	84	enable_kernel_altivec();
	85	ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key);
	86	pagefault_enable();
4f7f60d3	87
4beb1060 HX	88	ret += crypto_blkcipher_setkey(ctx->fallback, key, keylen);
4beb1060 HX	89	return ret;
4f7f60d3 MC	90	}
	91
	92	static void p8_aes_ctr_final(struct p8_aes_ctr_ctx *ctx,
4beb1060	93	struct blkcipher_walk *walk)
4f7f60d3	94	{
4beb1060 HX	95	u8 *ctrblk = walk->iv;
	96	u8 keystream[AES_BLOCK_SIZE];
	97	u8 *src = walk->src.virt.addr;
	98	u8 *dst = walk->dst.virt.addr;
	99	unsigned int nbytes = walk->nbytes;
	100
	101	pagefault_disable();
	102	enable_kernel_altivec();
	103	aes_p8_encrypt(ctrblk, keystream, &ctx->enc_key);
	104	pagefault_enable();
	105
	106	crypto_xor(keystream, src, nbytes);
	107	memcpy(dst, keystream, nbytes);
	108	crypto_inc(ctrblk, AES_BLOCK_SIZE);
4f7f60d3 MC	109	}
	110
	111	static int p8_aes_ctr_crypt(struct blkcipher_desc *desc,
4beb1060 HX	112	struct scatterlist *dst,
4beb1060 HX	113	struct scatterlist *src, unsigned int nbytes)
4f7f60d3	114	{
4beb1060 HX	115	int ret;
	116	struct blkcipher_walk walk;
	117	struct p8_aes_ctr_ctx *ctx =
	118	crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm));
	119	struct blkcipher_desc fallback_desc = {
	120	.tfm = ctx->fallback,
	121	.info = desc->info,
	122	.flags = desc->flags
	123	};
	124
	125	if (in_interrupt()) {
	126	ret = crypto_blkcipher_encrypt(&fallback_desc, dst, src,
	127	nbytes);
	128	} else {
	129	blkcipher_walk_init(&walk, dst, src, nbytes);
	130	ret = blkcipher_walk_virt_block(desc, &walk, AES_BLOCK_SIZE);
	131	while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) {
	132	pagefault_disable();
	133	enable_kernel_altivec();
	134	aes_p8_ctr32_encrypt_blocks(walk.src.virt.addr,
	135	walk.dst.virt.addr,
	136	(nbytes &
	137	AES_BLOCK_MASK) /
	138	AES_BLOCK_SIZE,
	139	&ctx->enc_key,
	140	walk.iv);
	141	pagefault_enable();
	142
	143	crypto_inc(walk.iv, AES_BLOCK_SIZE);
	144	nbytes &= AES_BLOCK_SIZE - 1;
	145	ret = blkcipher_walk_done(desc, &walk, nbytes);
	146	}
	147	if (walk.nbytes) {
	148	p8_aes_ctr_final(ctx, &walk);
	149	ret = blkcipher_walk_done(desc, &walk, 0);
	150	}
	151	}
	152
	153	return ret;
4f7f60d3 MC	154	}
	155
	156	struct crypto_alg p8_aes_ctr_alg = {
4beb1060 HX	157	.cra_name = "ctr(aes)",
	158	.cra_driver_name = "p8_aes_ctr",
	159	.cra_module = THIS_MODULE,
	160	.cra_priority = 1000,
	161	.cra_type = &crypto_blkcipher_type,
	162	.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER \| CRYPTO_ALG_NEED_FALLBACK,
	163	.cra_alignmask = 0,
	164	.cra_blocksize = 1,
	165	.cra_ctxsize = sizeof(struct p8_aes_ctr_ctx),
	166	.cra_init = p8_aes_ctr_init,
	167	.cra_exit = p8_aes_ctr_exit,
	168	.cra_blkcipher = {
	169	.ivsize = 0,
	170	.min_keysize = AES_MIN_KEY_SIZE,
	171	.max_keysize = AES_MAX_KEY_SIZE,
	172	.setkey = p8_aes_ctr_setkey,
	173	.encrypt = p8_aes_ctr_crypt,
	174	.decrypt = p8_aes_ctr_crypt,
	175	},
4f7f60d3	176	};