1/*
2 * AMD Cryptographic Coprocessor (CCP) crypto API support
3 *
4 * Copyright (C) 2013 Advanced Micro Devices, Inc.
5 *
6 * Author: Tom Lendacky <thomas.lendacky@amd.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13#include <linux/module.h>
14#include <linux/moduleparam.h>
15#include <linux/kernel.h>
16#include <linux/list.h>
17#include <linux/ccp.h>
18#include <linux/scatterlist.h>
19#include <crypto/internal/hash.h>
20
21#include "ccp-crypto.h"
22
23MODULE_AUTHOR("Tom Lendacky <thomas.lendacky@amd.com>");
24MODULE_LICENSE("GPL");
25MODULE_VERSION("1.0.0");
26MODULE_DESCRIPTION("AMD Cryptographic Coprocessor crypto API support");
27
28static unsigned int aes_disable;
29module_param(aes_disable, uint, 0444);
30MODULE_PARM_DESC(aes_disable, "Disable use of AES - any non-zero value");
31
32static unsigned int sha_disable;
33module_param(sha_disable, uint, 0444);
34MODULE_PARM_DESC(sha_disable, "Disable use of SHA - any non-zero value");
35
36
37/* List heads for the supported algorithms */
38static LIST_HEAD(hash_algs);
39static LIST_HEAD(cipher_algs);
40
41/* For any tfm, requests for that tfm must be returned on the order
42 * received.  With multiple queues available, the CCP can process more
43 * than one cmd at a time.  Therefore we must maintain a cmd list to insure
44 * the proper ordering of requests on a given tfm.
45 */
46struct ccp_crypto_queue {
47	struct list_head cmds;
48	struct list_head *backlog;
49	unsigned int cmd_count;
50};
51#define CCP_CRYPTO_MAX_QLEN	100
52
53static struct ccp_crypto_queue req_queue;
54static spinlock_t req_queue_lock;
55
56struct ccp_crypto_cmd {
57	struct list_head entry;
58
59	struct ccp_cmd *cmd;
60
61	/* Save the crypto_tfm and crypto_async_request addresses
62	 * separately to avoid any reference to a possibly invalid
63	 * crypto_async_request structure after invoking the request
64	 * callback
65	 */
66	struct crypto_async_request *req;
67	struct crypto_tfm *tfm;
68
69	/* Used for held command processing to determine state */
70	int ret;
71};
72
73struct ccp_crypto_cpu {
74	struct work_struct work;
75	struct completion completion;
76	struct ccp_crypto_cmd *crypto_cmd;
77	int err;
78};
79
80
81static inline bool ccp_crypto_success(int err)
82{
83	if (err && (err != -EINPROGRESS) && (err != -EBUSY))
84		return false;
85
86	return true;
87}
88
89static struct ccp_crypto_cmd *ccp_crypto_cmd_complete(
90	struct ccp_crypto_cmd *crypto_cmd, struct ccp_crypto_cmd **backlog)
91{
92	struct ccp_crypto_cmd *held = NULL, *tmp;
93	unsigned long flags;
94
95	*backlog = NULL;
96
97	spin_lock_irqsave(&req_queue_lock, flags);
98
99	/* Held cmds will be after the current cmd in the queue so start
100	 * searching for a cmd with a matching tfm for submission.
101	 */
102	tmp = crypto_cmd;
103	list_for_each_entry_continue(tmp, &req_queue.cmds, entry) {
104		if (crypto_cmd->tfm != tmp->tfm)
105			continue;
106		held = tmp;
107		break;
108	}
109
110	/* Process the backlog:
111	 *   Because cmds can be executed from any point in the cmd list
112	 *   special precautions have to be taken when handling the backlog.
113	 */
114	if (req_queue.backlog != &req_queue.cmds) {
115		/* Skip over this cmd if it is the next backlog cmd */
116		if (req_queue.backlog == &crypto_cmd->entry)
117			req_queue.backlog = crypto_cmd->entry.next;
118
119		*backlog = container_of(req_queue.backlog,
120					struct ccp_crypto_cmd, entry);
121		req_queue.backlog = req_queue.backlog->next;
122
123		/* Skip over this cmd if it is now the next backlog cmd */
124		if (req_queue.backlog == &crypto_cmd->entry)
125			req_queue.backlog = crypto_cmd->entry.next;
126	}
127
128	/* Remove the cmd entry from the list of cmds */
129	req_queue.cmd_count--;
130	list_del(&crypto_cmd->entry);
131
132	spin_unlock_irqrestore(&req_queue_lock, flags);
133
134	return held;
135}
136
137static void ccp_crypto_complete(void *data, int err)
138{
139	struct ccp_crypto_cmd *crypto_cmd = data;
140	struct ccp_crypto_cmd *held, *next, *backlog;
141	struct crypto_async_request *req = crypto_cmd->req;
142	struct ccp_ctx *ctx = crypto_tfm_ctx(req->tfm);
143	int ret;
144
145	if (err == -EINPROGRESS) {
146		/* Only propogate the -EINPROGRESS if necessary */
147		if (crypto_cmd->ret == -EBUSY) {
148			crypto_cmd->ret = -EINPROGRESS;
149			req->complete(req, -EINPROGRESS);
150		}
151
152		return;
153	}
154
155	/* Operation has completed - update the queue before invoking
156	 * the completion callbacks and retrieve the next cmd (cmd with
157	 * a matching tfm) that can be submitted to the CCP.
158	 */
159	held = ccp_crypto_cmd_complete(crypto_cmd, &backlog);
160	if (backlog) {
161		backlog->ret = -EINPROGRESS;
162		backlog->req->complete(backlog->req, -EINPROGRESS);
163	}
164
165	/* Transition the state from -EBUSY to -EINPROGRESS first */
166	if (crypto_cmd->ret == -EBUSY)
167		req->complete(req, -EINPROGRESS);
168
169	/* Completion callbacks */
170	ret = err;
171	if (ctx->complete)
172		ret = ctx->complete(req, ret);
173	req->complete(req, ret);
174
175	/* Submit the next cmd */
176	while (held) {
177		/* Since we have already queued the cmd, we must indicate that
178		 * we can backlog so as not to "lose" this request.
179		 */
180		held->cmd->flags |= CCP_CMD_MAY_BACKLOG;
181		ret = ccp_enqueue_cmd(held->cmd);
182		if (ccp_crypto_success(ret))
183			break;
184
185		/* Error occurred, report it and get the next entry */
186		ctx = crypto_tfm_ctx(held->req->tfm);
187		if (ctx->complete)
188			ret = ctx->complete(held->req, ret);
189		held->req->complete(held->req, ret);
190
191		next = ccp_crypto_cmd_complete(held, &backlog);
192		if (backlog) {
193			backlog->ret = -EINPROGRESS;
194			backlog->req->complete(backlog->req, -EINPROGRESS);
195		}
196
197		kfree(held);
198		held = next;
199	}
200
201	kfree(crypto_cmd);
202}
203
204static int ccp_crypto_enqueue_cmd(struct ccp_crypto_cmd *crypto_cmd)
205{
206	struct ccp_crypto_cmd *active = NULL, *tmp;
207	unsigned long flags;
208	bool free_cmd = true;
209	int ret;
210
211	spin_lock_irqsave(&req_queue_lock, flags);
212
213	/* Check if the cmd can/should be queued */
214	if (req_queue.cmd_count >= CCP_CRYPTO_MAX_QLEN) {
215		ret = -EBUSY;
216		if (!(crypto_cmd->cmd->flags & CCP_CMD_MAY_BACKLOG))
217			goto e_lock;
218	}
219
220	/* Look for an entry with the same tfm.  If there is a cmd
221	 * with the same tfm in the list then the current cmd cannot
222	 * be submitted to the CCP yet.
223	 */
224	list_for_each_entry(tmp, &req_queue.cmds, entry) {
225		if (crypto_cmd->tfm != tmp->tfm)
226			continue;
227		active = tmp;
228		break;
229	}
230
231	ret = -EINPROGRESS;
232	if (!active) {
233		ret = ccp_enqueue_cmd(crypto_cmd->cmd);
234		if (!ccp_crypto_success(ret))
235			goto e_lock;	/* Error, don't queue it */
236		if ((ret == -EBUSY) &&
237		    !(crypto_cmd->cmd->flags & CCP_CMD_MAY_BACKLOG))
238			goto e_lock;	/* Not backlogging, don't queue it */
239	}
240
241	if (req_queue.cmd_count >= CCP_CRYPTO_MAX_QLEN) {
242		ret = -EBUSY;
243		if (req_queue.backlog == &req_queue.cmds)
244			req_queue.backlog = &crypto_cmd->entry;
245	}
246	crypto_cmd->ret = ret;
247
248	req_queue.cmd_count++;
249	list_add_tail(&crypto_cmd->entry, &req_queue.cmds);
250
251	free_cmd = false;
252
253e_lock:
254	spin_unlock_irqrestore(&req_queue_lock, flags);
255
256	if (free_cmd)
257		kfree(crypto_cmd);
258
259	return ret;
260}
261
262/**
263 * ccp_crypto_enqueue_request - queue an crypto async request for processing
264 *				by the CCP
265 *
266 * @req: crypto_async_request struct to be processed
267 * @cmd: ccp_cmd struct to be sent to the CCP
268 */
269int ccp_crypto_enqueue_request(struct crypto_async_request *req,
270			       struct ccp_cmd *cmd)
271{
272	struct ccp_crypto_cmd *crypto_cmd;
273	gfp_t gfp;
274
275	gfp = req->flags & CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL : GFP_ATOMIC;
276
277	crypto_cmd = kzalloc(sizeof(*crypto_cmd), gfp);
278	if (!crypto_cmd)
279		return -ENOMEM;
280
281	/* The tfm pointer must be saved and not referenced from the
282	 * crypto_async_request (req) pointer because it is used after
283	 * completion callback for the request and the req pointer
284	 * might not be valid anymore.
285	 */
286	crypto_cmd->cmd = cmd;
287	crypto_cmd->req = req;
288	crypto_cmd->tfm = req->tfm;
289
290	cmd->callback = ccp_crypto_complete;
291	cmd->data = crypto_cmd;
292
293	if (req->flags & CRYPTO_TFM_REQ_MAY_BACKLOG)
294		cmd->flags |= CCP_CMD_MAY_BACKLOG;
295	else
296		cmd->flags &= ~CCP_CMD_MAY_BACKLOG;
297
298	return ccp_crypto_enqueue_cmd(crypto_cmd);
299}
300
301struct scatterlist *ccp_crypto_sg_table_add(struct sg_table *table,
302					    struct scatterlist *sg_add)
303{
304	struct scatterlist *sg, *sg_last = NULL;
305
306	for (sg = table->sgl; sg; sg = sg_next(sg))
307		if (!sg_page(sg))
308			break;
309	BUG_ON(!sg);
310
311	for (; sg && sg_add; sg = sg_next(sg), sg_add = sg_next(sg_add)) {
312		sg_set_page(sg, sg_page(sg_add), sg_add->length,
313			    sg_add->offset);
314		sg_last = sg;
315	}
316	BUG_ON(sg_add);
317
318	return sg_last;
319}
320
321static int ccp_register_algs(void)
322{
323	int ret;
324
325	if (!aes_disable) {
326		ret = ccp_register_aes_algs(&cipher_algs);
327		if (ret)
328			return ret;
329
330		ret = ccp_register_aes_cmac_algs(&hash_algs);
331		if (ret)
332			return ret;
333
334		ret = ccp_register_aes_xts_algs(&cipher_algs);
335		if (ret)
336			return ret;
337	}
338
339	if (!sha_disable) {
340		ret = ccp_register_sha_algs(&hash_algs);
341		if (ret)
342			return ret;
343	}
344
345	return 0;
346}
347
348static void ccp_unregister_algs(void)
349{
350	struct ccp_crypto_ahash_alg *ahash_alg, *ahash_tmp;
351	struct ccp_crypto_ablkcipher_alg *ablk_alg, *ablk_tmp;
352
353	list_for_each_entry_safe(ahash_alg, ahash_tmp, &hash_algs, entry) {
354		crypto_unregister_ahash(&ahash_alg->alg);
355		list_del(&ahash_alg->entry);
356		kfree(ahash_alg);
357	}
358
359	list_for_each_entry_safe(ablk_alg, ablk_tmp, &cipher_algs, entry) {
360		crypto_unregister_alg(&ablk_alg->alg);
361		list_del(&ablk_alg->entry);
362		kfree(ablk_alg);
363	}
364}
365
366static int ccp_crypto_init(void)
367{
368	int ret;
369
370	ret = ccp_present();
371	if (ret)
372		return ret;
373
374	spin_lock_init(&req_queue_lock);
375	INIT_LIST_HEAD(&req_queue.cmds);
376	req_queue.backlog = &req_queue.cmds;
377	req_queue.cmd_count = 0;
378
379	ret = ccp_register_algs();
380	if (ret)
381		ccp_unregister_algs();
382
383	return ret;
384}
385
386static void ccp_crypto_exit(void)
387{
388	ccp_unregister_algs();
389}
390
391module_init(ccp_crypto_init);
392module_exit(ccp_crypto_exit);
393