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 
23 MODULE_AUTHOR("Tom Lendacky <thomas.lendacky@amd.com>");
24 MODULE_LICENSE("GPL");
25 MODULE_VERSION("1.0.0");
26 MODULE_DESCRIPTION("AMD Cryptographic Coprocessor crypto API support");
27 
28 static unsigned int aes_disable;
29 module_param(aes_disable, uint, 0444);
30 MODULE_PARM_DESC(aes_disable, "Disable use of AES - any non-zero value");
31 
32 static unsigned int sha_disable;
33 module_param(sha_disable, uint, 0444);
34 MODULE_PARM_DESC(sha_disable, "Disable use of SHA - any non-zero value");
35 
36 
37 /* List heads for the supported algorithms */
38 static LIST_HEAD(hash_algs);
39 static 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  */
46 struct 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 
53 static struct ccp_crypto_queue req_queue;
54 static spinlock_t req_queue_lock;
55 
56 struct 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 
73 struct 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 
81 static inline bool ccp_crypto_success(int err)
82 {
83 	if (err && (err != -EINPROGRESS) && (err != -EBUSY))
84 		return false;
85 
86 	return true;
87 }
88 
89 static 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 
137 static 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 
204 static 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 
253 e_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  */
269 int 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 
301 struct 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 
321 static 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 
348 static 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 
366 static int ccp_crypto_init(void)
367 {
368 	int ret;
369 
370 	spin_lock_init(&req_queue_lock);
371 	INIT_LIST_HEAD(&req_queue.cmds);
372 	req_queue.backlog = &req_queue.cmds;
373 	req_queue.cmd_count = 0;
374 
375 	ret = ccp_register_algs();
376 	if (ret)
377 		ccp_unregister_algs();
378 
379 	return ret;
380 }
381 
382 static void ccp_crypto_exit(void)
383 {
384 	ccp_unregister_algs();
385 }
386 
387 module_init(ccp_crypto_init);
388 module_exit(ccp_crypto_exit);
389