summaryrefslogtreecommitdiff
path: root/drivers/tee/optee/supp.c
blob: 43626e15703a80ddf48360c0622f37b813b76809 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
/*
 * Copyright (c) 2015, Linaro Limited
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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.
 *
 */
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include "optee_private.h"

struct optee_supp_req {
	struct list_head link;

	bool in_queue;
	u32 func;
	u32 ret;
	size_t num_params;
	struct tee_param *param;

	struct completion c;
};

void optee_supp_init(struct optee_supp *supp)
{
	memset(supp, 0, sizeof(*supp));
	mutex_init(&supp->mutex);
	init_completion(&supp->reqs_c);
	idr_init(&supp->idr);
	INIT_LIST_HEAD(&supp->reqs);
	supp->req_id = -1;
}

void optee_supp_uninit(struct optee_supp *supp)
{
	mutex_destroy(&supp->mutex);
	idr_destroy(&supp->idr);
}

void optee_supp_release(struct optee_supp *supp)
{
	int id;
	struct optee_supp_req *req;
	struct optee_supp_req *req_tmp;

	mutex_lock(&supp->mutex);

	/* Abort all request retrieved by supplicant */
	idr_for_each_entry(&supp->idr, req, id) {
		idr_remove(&supp->idr, id);
		req->ret = TEEC_ERROR_COMMUNICATION;
		complete(&req->c);
	}

	/* Abort all queued requests */
	list_for_each_entry_safe(req, req_tmp, &supp->reqs, link) {
		list_del(&req->link);
		req->in_queue = false;
		req->ret = TEEC_ERROR_COMMUNICATION;
		complete(&req->c);
	}

	supp->ctx = NULL;
	supp->req_id = -1;

	mutex_unlock(&supp->mutex);
}

/**
 * optee_supp_thrd_req() - request service from supplicant
 * @ctx:	context doing the request
 * @func:	function requested
 * @num_params:	number of elements in @param array
 * @param:	parameters for function
 *
 * Returns result of operation to be passed to secure world
 */
u32 optee_supp_thrd_req(struct tee_context *ctx, u32 func, size_t num_params,
			struct tee_param *param)

{
	struct optee *optee = tee_get_drvdata(ctx->teedev);
	struct optee_supp *supp = &optee->supp;
	struct optee_supp_req *req = kzalloc(sizeof(*req), GFP_KERNEL);
	bool interruptable;
	u32 ret;

	if (!req)
		return TEEC_ERROR_OUT_OF_MEMORY;

	init_completion(&req->c);
	req->func = func;
	req->num_params = num_params;
	req->param = param;

	/* Insert the request in the request list */
	mutex_lock(&supp->mutex);
	list_add_tail(&req->link, &supp->reqs);
	req->in_queue = true;
	mutex_unlock(&supp->mutex);

	/* Tell an eventual waiter there's a new request */
	complete(&supp->reqs_c);

	/*
	 * Wait for supplicant to process and return result, once we've
	 * returned from wait_for_completion(&req->c) successfully we have
	 * exclusive access again.
	 */
	while (wait_for_completion_interruptible(&req->c)) {
		mutex_lock(&supp->mutex);
		interruptable = !supp->ctx;
		if (interruptable) {
			/*
			 * There's no supplicant available and since the
			 * supp->mutex currently is held none can
			 * become available until the mutex released
			 * again.
			 *
			 * Interrupting an RPC to supplicant is only
			 * allowed as a way of slightly improving the user
			 * experience in case the supplicant hasn't been
			 * started yet. During normal operation the supplicant
			 * will serve all requests in a timely manner and
			 * interrupting then wouldn't make sense.
			 */
			if (req->in_queue) {
				list_del(&req->link);
				req->in_queue = false;
			}
		}
		mutex_unlock(&supp->mutex);

		if (interruptable) {
			req->ret = TEEC_ERROR_COMMUNICATION;
			break;
		}
	}

	ret = req->ret;
	kfree(req);

	return ret;
}

static struct optee_supp_req  *supp_pop_entry(struct optee_supp *supp,
					      int num_params, int *id)
{
	struct optee_supp_req *req;

	if (supp->req_id != -1) {
		/*
		 * Supplicant should not mix synchronous and asnynchronous
		 * requests.
		 */
		return ERR_PTR(-EINVAL);
	}

	if (list_empty(&supp->reqs))
		return NULL;

	req = list_first_entry(&supp->reqs, struct optee_supp_req, link);

	if (num_params < req->num_params) {
		/* Not enough room for parameters */
		return ERR_PTR(-EINVAL);
	}

	*id = idr_alloc(&supp->idr, req, 1, 0, GFP_KERNEL);
	if (*id < 0)
		return ERR_PTR(-ENOMEM);

	list_del(&req->link);
	req->in_queue = false;

	return req;
}

static int supp_check_recv_params(size_t num_params, struct tee_param *params,
				  size_t *num_meta)
{
	size_t n;

	if (!num_params)
		return -EINVAL;

	/*
	 * If there's memrefs we need to decrease those as they where
	 * increased earlier and we'll even refuse to accept any below.
	 */
	for (n = 0; n < num_params; n++)
		if (tee_param_is_memref(params + n) && params[n].u.memref.shm)
			tee_shm_put(params[n].u.memref.shm);

	/*
	 * We only expect parameters as TEE_IOCTL_PARAM_ATTR_TYPE_NONE with
	 * or without the TEE_IOCTL_PARAM_ATTR_META bit set.
	 */
	for (n = 0; n < num_params; n++)
		if (params[n].attr &&
		    params[n].attr != TEE_IOCTL_PARAM_ATTR_META)
			return -EINVAL;

	/* At most we'll need one meta parameter so no need to check for more */
	if (params->attr == TEE_IOCTL_PARAM_ATTR_META)
		*num_meta = 1;
	else
		*num_meta = 0;

	return 0;
}

/**
 * optee_supp_recv() - receive request for supplicant
 * @ctx:	context receiving the request
 * @func:	requested function in supplicant
 * @num_params:	number of elements allocated in @param, updated with number
 *		used elements
 * @param:	space for parameters for @func
 *
 * Returns 0 on success or <0 on failure
 */
int optee_supp_recv(struct tee_context *ctx, u32 *func, u32 *num_params,
		    struct tee_param *param)
{
	struct tee_device *teedev = ctx->teedev;
	struct optee *optee = tee_get_drvdata(teedev);
	struct optee_supp *supp = &optee->supp;
	struct optee_supp_req *req = NULL;
	int id;
	size_t num_meta;
	int rc;

	rc = supp_check_recv_params(*num_params, param, &num_meta);
	if (rc)
		return rc;

	while (true) {
		mutex_lock(&supp->mutex);
		req = supp_pop_entry(supp, *num_params - num_meta, &id);
		mutex_unlock(&supp->mutex);

		if (req) {
			if (IS_ERR(req))
				return PTR_ERR(req);
			break;
		}

		/*
		 * If we didn't get a request we'll block in
		 * wait_for_completion() to avoid needless spinning.
		 *
		 * This is where supplicant will be hanging most of
		 * the time, let's make this interruptable so we
		 * can easily restart supplicant if needed.
		 */
		if (wait_for_completion_interruptible(&supp->reqs_c))
			return -ERESTARTSYS;
	}

	if (num_meta) {
		/*
		 * tee-supplicant support meta parameters -> requsts can be
		 * processed asynchronously.
		 */
		param->attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT |
			      TEE_IOCTL_PARAM_ATTR_META;
		param->u.value.a = id;
		param->u.value.b = 0;
		param->u.value.c = 0;
	} else {
		mutex_lock(&supp->mutex);
		supp->req_id = id;
		mutex_unlock(&supp->mutex);
	}

	*func = req->func;
	*num_params = req->num_params + num_meta;
	memcpy(param + num_meta, req->param,
	       sizeof(struct tee_param) * req->num_params);

	return 0;
}

static struct optee_supp_req *supp_pop_req(struct optee_supp *supp,
					   size_t num_params,
					   struct tee_param *param,
					   size_t *num_meta)
{
	struct optee_supp_req *req;
	int id;
	size_t nm;
	const u32 attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT |
			 TEE_IOCTL_PARAM_ATTR_META;

	if (!num_params)
		return ERR_PTR(-EINVAL);

	if (supp->req_id == -1) {
		if (param->attr != attr)
			return ERR_PTR(-EINVAL);
		id = param->u.value.a;
		nm = 1;
	} else {
		id = supp->req_id;
		nm = 0;
	}

	req = idr_find(&supp->idr, id);
	if (!req)
		return ERR_PTR(-ENOENT);

	if ((num_params - nm) != req->num_params)
		return ERR_PTR(-EINVAL);

	idr_remove(&supp->idr, id);
	supp->req_id = -1;
	*num_meta = nm;

	return req;
}

/**
 * optee_supp_send() - send result of request from supplicant
 * @ctx:	context sending result
 * @ret:	return value of request
 * @num_params:	number of parameters returned
 * @param:	returned parameters
 *
 * Returns 0 on success or <0 on failure.
 */
int optee_supp_send(struct tee_context *ctx, u32 ret, u32 num_params,
		    struct tee_param *param)
{
	struct tee_device *teedev = ctx->teedev;
	struct optee *optee = tee_get_drvdata(teedev);
	struct optee_supp *supp = &optee->supp;
	struct optee_supp_req *req;
	size_t n;
	size_t num_meta;

	mutex_lock(&supp->mutex);
	req = supp_pop_req(supp, num_params, param, &num_meta);
	mutex_unlock(&supp->mutex);

	if (IS_ERR(req)) {
		/* Something is wrong, let supplicant restart. */
		return PTR_ERR(req);
	}

	/* Update out and in/out parameters */
	for (n = 0; n < req->num_params; n++) {
		struct tee_param *p = req->param + n;

		switch (p->attr & TEE_IOCTL_PARAM_ATTR_TYPE_MASK) {
		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT:
		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT:
			p->u.value.a = param[n + num_meta].u.value.a;
			p->u.value.b = param[n + num_meta].u.value.b;
			p->u.value.c = param[n + num_meta].u.value.c;
			break;
		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
			p->u.memref.size = param[n + num_meta].u.memref.size;
			break;
		default:
			break;
		}
	}
	req->ret = ret;

	/* Let the requesting thread continue */
	complete(&req->c);

	return 0;
}