safexcel_cipher.c

/*
 * Copyright (C) 2017 Marvell
 *
 * Antoine Tenart <antoine.tenart@free-electrons.com>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>

#include <crypto/aes.h>
#include <crypto/skcipher.h>
#include <crypto/internal/skcipher.h>

#include "safexcel.h"

enum safexcel_cipher_direction {
	SAFEXCEL_ENCRYPT,
	SAFEXCEL_DECRYPT,
};

struct safexcel_cipher_ctx {
	struct safexcel_context base;
	struct safexcel_crypto_priv *priv;

	u32 mode;

	__le32 key[8];
	unsigned int key_len;
};

struct safexcel_cipher_req {
	enum safexcel_cipher_direction direction;
	bool needs_inv;
};

static void safexcel_skcipher_token(struct safexcel_cipher_ctx *ctx, u8 *iv,
				    struct safexcel_command_desc *cdesc,
				    u32 length)
{
	struct safexcel_token *token;
	unsigned offset = 0;

	if (ctx->mode == CONTEXT_CONTROL_CRYPTO_MODE_CBC) {
		offset = AES_BLOCK_SIZE / sizeof(u32);
		memcpy(cdesc->control_data.token, iv, AES_BLOCK_SIZE);

		cdesc->control_data.options |= EIP197_OPTION_4_TOKEN_IV_CMD;
	}

	token = (struct safexcel_token *)(cdesc->control_data.token + offset);

	token[0].opcode = EIP197_TOKEN_OPCODE_DIRECTION;
	token[0].packet_length = length;
	token[0].stat = EIP197_TOKEN_STAT_LAST_PACKET |
			EIP197_TOKEN_STAT_LAST_HASH;
	token[0].instructions = EIP197_TOKEN_INS_LAST |
				EIP197_TOKEN_INS_TYPE_CRYTO |
				EIP197_TOKEN_INS_TYPE_OUTPUT;
}

static int safexcel_skcipher_aes_setkey(struct crypto_skcipher *ctfm,
					const u8 *key, unsigned int len)
{
	struct crypto_tfm *tfm = crypto_skcipher_tfm(ctfm);
	struct safexcel_cipher_ctx *ctx = crypto_tfm_ctx(tfm);
	struct safexcel_crypto_priv *priv = ctx->priv;
	struct crypto_aes_ctx aes;
	int ret, i;

	ret = crypto_aes_expand_key(&aes, key, len);
	if (ret) {
		crypto_skcipher_set_flags(ctfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
		return ret;
	}

	if (priv->version == EIP197 && ctx->base.ctxr_dma) {
		for (i = 0; i < len / sizeof(u32); i++) {
			if (ctx->key[i] != cpu_to_le32(aes.key_enc[i])) {
				ctx->base.needs_inv = true;
				break;
			}
		}
	}

	for (i = 0; i < len / sizeof(u32); i++)
		ctx->key[i] = cpu_to_le32(aes.key_enc[i]);

	ctx->key_len = len;

	memzero_explicit(&aes, sizeof(aes));
	return 0;
}

static int safexcel_context_control(struct safexcel_cipher_ctx *ctx,
				    struct crypto_async_request *async,
				    struct safexcel_cipher_req *sreq,
				    struct safexcel_command_desc *cdesc)
{
	struct safexcel_crypto_priv *priv = ctx->priv;
	int ctrl_size;

	cdesc->control_data.control0 |= CONTEXT_CONTROL_TYPE_CRYPTO_OUT;

	/* The decryption control type is a combination of the encryption type
	 * and CONTEXT_CONTROL_TYPE_NULL_IN, for all types.
	 */
	if (sreq->direction == SAFEXCEL_DECRYPT)
		cdesc->control_data.control0 |= CONTEXT_CONTROL_TYPE_NULL_IN;

	cdesc->control_data.control0 |= CONTEXT_CONTROL_KEY_EN;
	cdesc->control_data.control1 |= ctx->mode;

	switch (ctx->key_len) {
	case AES_KEYSIZE_128:
		cdesc->control_data.control0 |= CONTEXT_CONTROL_CRYPTO_ALG_AES128;
		ctrl_size = 4;
		break;
	case AES_KEYSIZE_192:
		cdesc->control_data.control0 |= CONTEXT_CONTROL_CRYPTO_ALG_AES192;
		ctrl_size = 6;
		break;
	case AES_KEYSIZE_256:
		cdesc->control_data.control0 |= CONTEXT_CONTROL_CRYPTO_ALG_AES256;
		ctrl_size = 8;
		break;
	default:
		dev_err(priv->dev, "aes keysize not supported: %u\n",
			ctx->key_len);
		return -EINVAL;
	}
	cdesc->control_data.control0 |= CONTEXT_CONTROL_SIZE(ctrl_size);

	return 0;
}

static int safexcel_handle_req_result(struct safexcel_crypto_priv *priv, int ring,
				      struct crypto_async_request *async,
				      struct scatterlist *src,
				      struct scatterlist *dst,
				      unsigned int cryptlen,
				      struct safexcel_cipher_req *sreq,
				      bool *should_complete, int *ret)
{
	struct safexcel_result_desc *rdesc;
	int ndesc = 0;

	*ret = 0;

	spin_lock_bh(&priv->ring[ring].egress_lock);
	do {
		rdesc = safexcel_ring_next_rptr(priv, &priv->ring[ring].rdr);
		if (IS_ERR(rdesc)) {
			dev_err(priv->dev,
				"cipher: result: could not retrieve the result descriptor\n");
			*ret = PTR_ERR(rdesc);
			break;
		}

		if (rdesc->result_data.error_code) {
			dev_err(priv->dev,
				"cipher: result: result descriptor error (%d)\n",
				rdesc->result_data.error_code);
			*ret = -EIO;
		}

		ndesc++;
	} while (!rdesc->last_seg);

	safexcel_complete(priv, ring);
	spin_unlock_bh(&priv->ring[ring].egress_lock);

	if (src == dst) {
		dma_unmap_sg(priv->dev, src,
			     sg_nents_for_len(src, cryptlen),
			     DMA_BIDIRECTIONAL);
	} else {
		dma_unmap_sg(priv->dev, src,
			     sg_nents_for_len(src, cryptlen),
			     DMA_TO_DEVICE);
		dma_unmap_sg(priv->dev, dst,
			     sg_nents_for_len(dst, cryptlen),
			     DMA_FROM_DEVICE);
	}

	*should_complete = true;

	return ndesc;
}

static int safexcel_aes_send(struct crypto_async_request *base, int ring,
			     struct safexcel_request *request,
			     struct safexcel_cipher_req *sreq,
			     struct scatterlist *src, struct scatterlist *dst,
			     unsigned int cryptlen, u8 *iv, int *commands,
			     int *results)
{
	struct safexcel_cipher_ctx *ctx = crypto_tfm_ctx(base->tfm);
	struct safexcel_crypto_priv *priv = ctx->priv;
	struct safexcel_command_desc *cdesc;
	struct safexcel_result_desc *rdesc;
	struct scatterlist *sg;
	int nr_src, nr_dst, n_cdesc = 0, n_rdesc = 0, queued = cryptlen;
	int i, ret = 0;

	if (src == dst) {
		nr_src = dma_map_sg(priv->dev, src,
				    sg_nents_for_len(src, cryptlen),
				    DMA_BIDIRECTIONAL);
		nr_dst = nr_src;
		if (!nr_src)
			return -EINVAL;
	} else {
		nr_src = dma_map_sg(priv->dev, src,
				    sg_nents_for_len(src, cryptlen),
				    DMA_TO_DEVICE);
		if (!nr_src)
			return -EINVAL;

		nr_dst = dma_map_sg(priv->dev, dst,
				    sg_nents_for_len(dst, cryptlen),
				    DMA_FROM_DEVICE);
		if (!nr_dst) {
			dma_unmap_sg(priv->dev, src,
				     sg_nents_for_len(src, cryptlen),
				     DMA_TO_DEVICE);
			return -EINVAL;
		}
	}

	memcpy(ctx->base.ctxr->data, ctx->key, ctx->key_len);

	spin_lock_bh(&priv->ring[ring].egress_lock);

	/* command descriptors */
	for_each_sg(src, sg, nr_src, i) {
		int len = sg_dma_len(sg);

		/* Do not overflow the request */
		if (queued - len < 0)
			len = queued;

		cdesc = safexcel_add_cdesc(priv, ring, !n_cdesc, !(queued - len),
					   sg_dma_address(sg), len, cryptlen,
					   ctx->base.ctxr_dma);
		if (IS_ERR(cdesc)) {
			/* No space left in the command descriptor ring */
			ret = PTR_ERR(cdesc);
			goto cdesc_rollback;
		}
		n_cdesc++;

		if (n_cdesc == 1) {
			safexcel_context_control(ctx, base, sreq, cdesc);
			safexcel_skcipher_token(ctx, iv, cdesc, cryptlen);
		}

		queued -= len;
		if (!queued)
			break;
	}

	/* result descriptors */
	for_each_sg(dst, sg, nr_dst, i) {
		bool first = !i, last = (i == nr_dst - 1);
		u32 len = sg_dma_len(sg);

		rdesc = safexcel_add_rdesc(priv, ring, first, last,
					   sg_dma_address(sg), len);
		if (IS_ERR(rdesc)) {
			/* No space left in the result descriptor ring */
			ret = PTR_ERR(rdesc);
			goto rdesc_rollback;
		}
		n_rdesc++;
	}

	spin_unlock_bh(&priv->ring[ring].egress_lock);

	request->req = base;

	*commands = n_cdesc;
	*results = n_rdesc;
	return 0;

rdesc_rollback:
	for (i = 0; i < n_rdesc; i++)
		safexcel_ring_rollback_wptr(priv, &priv->ring[ring].rdr);
cdesc_rollback:
	for (i = 0; i < n_cdesc; i++)
		safexcel_ring_rollback_wptr(priv, &priv->ring[ring].cdr);

	spin_unlock_bh(&priv->ring[ring].egress_lock);

	if (src == dst) {
		dma_unmap_sg(priv->dev, src,
			     sg_nents_for_len(src, cryptlen),
			     DMA_BIDIRECTIONAL);
	} else {
		dma_unmap_sg(priv->dev, src,
			     sg_nents_for_len(src, cryptlen),
			     DMA_TO_DEVICE);
		dma_unmap_sg(priv->dev, dst,
			     sg_nents_for_len(dst, cryptlen),
			     DMA_FROM_DEVICE);
	}

	return ret;
}

static int safexcel_handle_inv_result(struct safexcel_crypto_priv *priv,
				      int ring,
				      struct crypto_async_request *base,
				      bool *should_complete, int *ret)
{
	struct safexcel_cipher_ctx *ctx = crypto_tfm_ctx(base->tfm);
	struct safexcel_result_desc *rdesc;
	int ndesc = 0, enq_ret;

	*ret = 0;

	spin_lock_bh(&priv->ring[ring].egress_lock);
	do {
		rdesc = safexcel_ring_next_rptr(priv, &priv->ring[ring].rdr);
		if (IS_ERR(rdesc)) {
			dev_err(priv->dev,
				"cipher: invalidate: could not retrieve the result descriptor\n");
			*ret = PTR_ERR(rdesc);
			break;
		}

		if (rdesc->result_data.error_code) {
			dev_err(priv->dev, "cipher: invalidate: result descriptor error (%d)\n",
				rdesc->result_data.error_code);
			*ret = -EIO;
		}

		ndesc++;
	} while (!rdesc->last_seg);

	safexcel_complete(priv, ring);
	spin_unlock_bh(&priv->ring[ring].egress_lock);

	if (ctx->base.exit_inv) {
		dma_pool_free(priv->context_pool, ctx->base.ctxr,
			      ctx->base.ctxr_dma);

		*should_complete = true;

		return ndesc;
	}

	ring = safexcel_select_ring(priv);
	ctx->base.ring = ring;

	spin_lock_bh(&priv->ring[ring].queue_lock);
	enq_ret = crypto_enqueue_request(&priv->ring[ring].queue, base);
	spin_unlock_bh(&priv->ring[ring].queue_lock);

	if (enq_ret != -EINPROGRESS)
		*ret = enq_ret;

	queue_work(priv->ring[ring].workqueue,
		   &priv->ring[ring].work_data.work);

	*should_complete = false;

	return ndesc;
}

static int safexcel_skcipher_handle_result(struct safexcel_crypto_priv *priv,
					   int ring,
					   struct crypto_async_request *async,
					   bool *should_complete, int *ret)
{
	struct skcipher_request *req = skcipher_request_cast(async);
	struct safexcel_cipher_req *sreq = skcipher_request_ctx(req);
	int err;

	if (sreq->needs_inv) {
		sreq->needs_inv = false;
		err = safexcel_handle_inv_result(priv, ring, async,
						 should_complete, ret);
	} else {
		err = safexcel_handle_req_result(priv, ring, async, req->src,
						 req->dst, req->cryptlen, sreq,
						 should_complete, ret);
	}

	return err;
}

static int safexcel_cipher_send_inv(struct crypto_async_request *base,
				    int ring, struct safexcel_request *request,
				    int *commands, int *results)
{
	struct safexcel_cipher_ctx *ctx = crypto_tfm_ctx(base->tfm);
	struct safexcel_crypto_priv *priv = ctx->priv;
	int ret;

	ret = safexcel_invalidate_cache(base, priv, ctx->base.ctxr_dma, ring,
					request);
	if (unlikely(ret))
		return ret;

	*commands = 1;
	*results = 1;

	return 0;
}

static int safexcel_skcipher_send(struct crypto_async_request *async, int ring,
				  struct safexcel_request *request,
				  int *commands, int *results)
{
	struct skcipher_request *req = skcipher_request_cast(async);
	struct safexcel_cipher_ctx *ctx = crypto_tfm_ctx(req->base.tfm);
	struct safexcel_cipher_req *sreq = skcipher_request_ctx(req);
	struct safexcel_crypto_priv *priv = ctx->priv;
	int ret;

	BUG_ON(priv->version == EIP97 && sreq->needs_inv);

	if (sreq->needs_inv)
		ret = safexcel_cipher_send_inv(async, ring, request, commands,
					       results);
	else
		ret = safexcel_aes_send(async, ring, request, sreq, req->src,
					req->dst, req->cryptlen, req->iv,
					commands, results);
	return ret;
}

static int safexcel_cipher_exit_inv(struct crypto_tfm *tfm,
				    struct crypto_async_request *base,
				    struct safexcel_cipher_req *sreq,
				    struct safexcel_inv_result *result)
{
	struct safexcel_cipher_ctx *ctx = crypto_tfm_ctx(tfm);
	struct safexcel_crypto_priv *priv = ctx->priv;
	int ring = ctx->base.ring;

	init_completion(&result->completion);

	ctx = crypto_tfm_ctx(base->tfm);
	ctx->base.exit_inv = true;
	sreq->needs_inv = true;

	spin_lock_bh(&priv->ring[ring].queue_lock);
	crypto_enqueue_request(&priv->ring[ring].queue, base);
	spin_unlock_bh(&priv->ring[ring].queue_lock);

	queue_work(priv->ring[ring].workqueue,
		   &priv->ring[ring].work_data.work);

	wait_for_completion(&result->completion);

	if (result->error) {
		dev_warn(priv->dev,
			"cipher: sync: invalidate: completion error %d\n",
			 result->error);
		return result->error;
	}

	return 0;
}

static int safexcel_skcipher_exit_inv(struct crypto_tfm *tfm)
{
	EIP197_REQUEST_ON_STACK(req, skcipher, EIP197_SKCIPHER_REQ_SIZE);
	struct safexcel_cipher_req *sreq = skcipher_request_ctx(req);
	struct safexcel_inv_result result = {};

	memset(req, 0, sizeof(struct skcipher_request));

	skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
				      safexcel_inv_complete, &result);
	skcipher_request_set_tfm(req, __crypto_skcipher_cast(tfm));

	return safexcel_cipher_exit_inv(tfm, &req->base, sreq, &result);
}

static int safexcel_aes(struct crypto_async_request *base,
			struct safexcel_cipher_req *sreq,
			enum safexcel_cipher_direction dir, u32 mode)
{
	struct safexcel_cipher_ctx *ctx = crypto_tfm_ctx(base->tfm);
	struct safexcel_crypto_priv *priv = ctx->priv;
	int ret, ring;

	sreq->needs_inv = false;
	sreq->direction = dir;
	ctx->mode = mode;

	if (ctx->base.ctxr) {
		if (priv->version == EIP197 && ctx->base.needs_inv) {
			sreq->needs_inv = true;
			ctx->base.needs_inv = false;
		}
	} else {
		ctx->base.ring = safexcel_select_ring(priv);
		ctx->base.ctxr = dma_pool_zalloc(priv->context_pool,
						 EIP197_GFP_FLAGS(*base),
						 &ctx->base.ctxr_dma);
		if (!ctx->base.ctxr)
			return -ENOMEM;
	}

	ring = ctx->base.ring;

	spin_lock_bh(&priv->ring[ring].queue_lock);
	ret = crypto_enqueue_request(&priv->ring[ring].queue, base);
	spin_unlock_bh(&priv->ring[ring].queue_lock);

	queue_work(priv->ring[ring].workqueue,
		   &priv->ring[ring].work_data.work);

	return ret;
}

static int safexcel_ecb_aes_encrypt(struct skcipher_request *req)
{
	return safexcel_aes(&req->base, skcipher_request_ctx(req),
			    SAFEXCEL_ENCRYPT, CONTEXT_CONTROL_CRYPTO_MODE_ECB);
}

static int safexcel_ecb_aes_decrypt(struct skcipher_request *req)
{
	return safexcel_aes(&req->base, skcipher_request_ctx(req),
			    SAFEXCEL_DECRYPT, CONTEXT_CONTROL_CRYPTO_MODE_ECB);
}

static int safexcel_skcipher_cra_init(struct crypto_tfm *tfm)
{
	struct safexcel_cipher_ctx *ctx = crypto_tfm_ctx(tfm);
	struct safexcel_alg_template *tmpl =
		container_of(tfm->__crt_alg, struct safexcel_alg_template,
			     alg.skcipher.base);

	crypto_skcipher_set_reqsize(__crypto_skcipher_cast(tfm),
				    sizeof(struct safexcel_cipher_req));

	ctx->priv = tmpl->priv;

	ctx->base.send = safexcel_skcipher_send;
	ctx->base.handle_result = safexcel_skcipher_handle_result;
	return 0;
}

static int safexcel_cipher_cra_exit(struct crypto_tfm *tfm)
{
	struct safexcel_cipher_ctx *ctx = crypto_tfm_ctx(tfm);

	memzero_explicit(ctx->key, 8 * sizeof(u32));

	/* context not allocated, skip invalidation */
	if (!ctx->base.ctxr)
		return -ENOMEM;

	memzero_explicit(ctx->base.ctxr->data, 8 * sizeof(u32));
	return 0;
}

static void safexcel_skcipher_cra_exit(struct crypto_tfm *tfm)
{
	struct safexcel_cipher_ctx *ctx = crypto_tfm_ctx(tfm);
	struct safexcel_crypto_priv *priv = ctx->priv;
	int ret;

	if (safexcel_cipher_cra_exit(tfm))
		return;

	if (priv->version == EIP197) {
		ret = safexcel_skcipher_exit_inv(tfm);
		if (ret)
			dev_warn(priv->dev, "skcipher: invalidation error %d\n",
				 ret);
	} else {
		dma_pool_free(priv->context_pool, ctx->base.ctxr,
			      ctx->base.ctxr_dma);
	}
}

struct safexcel_alg_template safexcel_alg_ecb_aes = {
	.type = SAFEXCEL_ALG_TYPE_SKCIPHER,
	.alg.skcipher = {
		.setkey = safexcel_skcipher_aes_setkey,
		.encrypt = safexcel_ecb_aes_encrypt,
		.decrypt = safexcel_ecb_aes_decrypt,
		.min_keysize = AES_MIN_KEY_SIZE,
		.max_keysize = AES_MAX_KEY_SIZE,
		.base = {
			.cra_name = "ecb(aes)",
			.cra_driver_name = "safexcel-ecb-aes",
			.cra_priority = 300,
			.cra_flags = CRYPTO_ALG_TYPE_SKCIPHER | CRYPTO_ALG_ASYNC |
				     CRYPTO_ALG_KERN_DRIVER_ONLY,
			.cra_blocksize = AES_BLOCK_SIZE,
			.cra_ctxsize = sizeof(struct safexcel_cipher_ctx),
			.cra_alignmask = 0,
			.cra_init = safexcel_skcipher_cra_init,
			.cra_exit = safexcel_skcipher_cra_exit,
			.cra_module = THIS_MODULE,
		},
	},
};

static int safexcel_cbc_aes_encrypt(struct skcipher_request *req)
{
	return safexcel_aes(&req->base, skcipher_request_ctx(req),
			    SAFEXCEL_ENCRYPT, CONTEXT_CONTROL_CRYPTO_MODE_CBC);
}

static int safexcel_cbc_aes_decrypt(struct skcipher_request *req)
{
	return safexcel_aes(&req->base, skcipher_request_ctx(req),
			    SAFEXCEL_DECRYPT, CONTEXT_CONTROL_CRYPTO_MODE_CBC);
}

struct safexcel_alg_template safexcel_alg_cbc_aes = {
	.type = SAFEXCEL_ALG_TYPE_SKCIPHER,
	.alg.skcipher = {
		.setkey = safexcel_skcipher_aes_setkey,
		.encrypt = safexcel_cbc_aes_encrypt,
		.decrypt = safexcel_cbc_aes_decrypt,
		.min_keysize = AES_MIN_KEY_SIZE,
		.max_keysize = AES_MAX_KEY_SIZE,
		.ivsize = AES_BLOCK_SIZE,
		.base = {
			.cra_name = "cbc(aes)",
			.cra_driver_name = "safexcel-cbc-aes",
			.cra_priority = 300,
			.cra_flags = CRYPTO_ALG_TYPE_SKCIPHER | CRYPTO_ALG_ASYNC |
				     CRYPTO_ALG_KERN_DRIVER_ONLY,
			.cra_blocksize = AES_BLOCK_SIZE,
			.cra_ctxsize = sizeof(struct safexcel_cipher_ctx),
			.cra_alignmask = 0,
			.cra_init = safexcel_skcipher_cra_init,
			.cra_exit = safexcel_skcipher_cra_exit,
			.cra_module = THIS_MODULE,
		},
	},
};