1 /*
2 * Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com
3 *
4 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
5 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
6 * All Rights Reserved.
7 *
8 * Author Rickard E. (Rik) Faith <faith@valinux.com>
9 * Author Gareth Hughes <gareth@valinux.com>
10 *
11 * Permission is hereby granted, free of charge, to any person obtaining a
12 * copy of this software and associated documentation files (the "Software"),
13 * to deal in the Software without restriction, including without limitation
14 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
15 * and/or sell copies of the Software, and to permit persons to whom the
16 * Software is furnished to do so, subject to the following conditions:
17 *
18 * The above copyright notice and this permission notice (including the next
19 * paragraph) shall be included in all copies or substantial portions of the
20 * Software.
21 *
22 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
23 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
25 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
26 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
27 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
28 * OTHER DEALINGS IN THE SOFTWARE.
29 */
30
31 #include <drm/drmP.h>
32 #include "drm_internal.h"
33 #include "drm_legacy.h"
34 #include <drm/drm_lease.h>
35
36 /**
37 * DOC: master and authentication
38 *
39 * &struct drm_master is used to track groups of clients with open
40 * primary/legacy device nodes. For every &struct drm_file which has had at
41 * least once successfully became the device master (either through the
42 * SET_MASTER IOCTL, or implicitly through opening the primary device node when
43 * no one else is the current master that time) there exists one &drm_master.
44 * This is noted in &drm_file.is_master. All other clients have just a pointer
45 * to the &drm_master they are associated with.
46 *
47 * In addition only one &drm_master can be the current master for a &drm_device.
48 * It can be switched through the DROP_MASTER and SET_MASTER IOCTL, or
49 * implicitly through closing/openeing the primary device node. See also
50 * drm_is_current_master().
51 *
52 * Clients can authenticate against the current master (if it matches their own)
53 * using the GETMAGIC and AUTHMAGIC IOCTLs. Together with exchanging masters,
54 * this allows controlled access to the device for an entire group of mutually
55 * trusted clients.
56 */
57
drm_getmagic(struct drm_device * dev,void * data,struct drm_file * file_priv)58 int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv)
59 {
60 struct drm_auth *auth = data;
61 int ret = 0;
62
63 mutex_lock(&dev->master_mutex);
64 if (!file_priv->magic) {
65 ret = idr_alloc(&file_priv->master->magic_map, file_priv,
66 1, 0, GFP_KERNEL);
67 if (ret >= 0)
68 file_priv->magic = ret;
69 }
70 auth->magic = file_priv->magic;
71 mutex_unlock(&dev->master_mutex);
72
73 DRM_DEBUG("%u\n", auth->magic);
74
75 return ret < 0 ? ret : 0;
76 }
77
drm_authmagic(struct drm_device * dev,void * data,struct drm_file * file_priv)78 int drm_authmagic(struct drm_device *dev, void *data,
79 struct drm_file *file_priv)
80 {
81 struct drm_auth *auth = data;
82 struct drm_file *file;
83
84 DRM_DEBUG("%u\n", auth->magic);
85
86 mutex_lock(&dev->master_mutex);
87 file = idr_find(&file_priv->master->magic_map, auth->magic);
88 if (file) {
89 file->authenticated = 1;
90 idr_replace(&file_priv->master->magic_map, NULL, auth->magic);
91 }
92 mutex_unlock(&dev->master_mutex);
93
94 return file ? 0 : -EINVAL;
95 }
96
drm_master_create(struct drm_device * dev)97 struct drm_master *drm_master_create(struct drm_device *dev)
98 {
99 struct drm_master *master;
100
101 master = kzalloc(sizeof(*master), GFP_KERNEL);
102 if (!master)
103 return NULL;
104
105 kref_init(&master->refcount);
106 lockinit(&master->lock.spinlock, "drmmls", 0, 0);
107 init_waitqueue_head(&master->lock.lock_queue);
108 idr_init(&master->magic_map);
109 master->dev = dev;
110
111 /* initialize the tree of output resource lessees */
112 master->lessor = NULL;
113 master->lessee_id = 0;
114 INIT_LIST_HEAD(&master->lessees);
115 INIT_LIST_HEAD(&master->lessee_list);
116 idr_init(&master->leases);
117 idr_init(&master->lessee_idr);
118
119 return master;
120 }
121
drm_set_master(struct drm_device * dev,struct drm_file * fpriv,bool new_master)122 static int drm_set_master(struct drm_device *dev, struct drm_file *fpriv,
123 bool new_master)
124 {
125 int ret = 0;
126
127 dev->master = drm_master_get(fpriv->master);
128 if (dev->driver->master_set) {
129 ret = dev->driver->master_set(dev, fpriv, new_master);
130 if (unlikely(ret != 0)) {
131 drm_master_put(&dev->master);
132 }
133 }
134
135 return ret;
136 }
137
drm_new_set_master(struct drm_device * dev,struct drm_file * fpriv)138 static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv)
139 {
140 struct drm_master *old_master;
141 int ret;
142
143 #if 0
144 lockdep_assert_held_once(&dev->master_mutex);
145 #endif
146
147 old_master = fpriv->master;
148 fpriv->master = drm_master_create(dev);
149 if (!fpriv->master) {
150 fpriv->master = old_master;
151 return -ENOMEM;
152 }
153
154 if (dev->driver->master_create) {
155 ret = dev->driver->master_create(dev, fpriv->master);
156 if (ret)
157 goto out_err;
158 }
159 fpriv->is_master = 1;
160 fpriv->authenticated = 1;
161
162 ret = drm_set_master(dev, fpriv, true);
163 if (ret)
164 goto out_err;
165
166 if (old_master)
167 drm_master_put(&old_master);
168
169 return 0;
170
171 out_err:
172 /* drop references and restore old master on failure */
173 drm_master_put(&fpriv->master);
174 fpriv->master = old_master;
175
176 return ret;
177 }
178
drm_setmaster_ioctl(struct drm_device * dev,void * data,struct drm_file * file_priv)179 int drm_setmaster_ioctl(struct drm_device *dev, void *data,
180 struct drm_file *file_priv)
181 {
182 int ret = 0;
183
184 mutex_lock(&dev->master_mutex);
185 if (drm_is_current_master(file_priv))
186 goto out_unlock;
187
188 /*
189 * dev->master is currently automatically set on first-open, which
190 * might or might not be what linux does. To avoid a later
191 * drm_setmaster ioctl failure, ignore the fact.
192 *
193 * XXX fixme
194 */
195 if (dev->master) {
196 kprintf("drm_setmaster_ioctl: already has one XXX ignored\n");
197 //ret = -EINVAL;
198 //goto out_unlock;
199 }
200
201 if (!file_priv->master) {
202 kprintf("drm_setmaster_ioctl: file_priv->master already\n");
203 ret = -EINVAL;
204 goto out_unlock;
205 }
206
207 if (!file_priv->is_master) {
208 kprintf("drm_setmaster_ioctl: is_not master, set master");
209 ret = drm_new_set_master(dev, file_priv);
210 goto out_unlock;
211 }
212
213 if (file_priv->master->lessor != NULL) {
214 DRM_DEBUG_LEASE("Attempt to set lessee %d as master\n", file_priv->master->lessee_id);
215 ret = -EINVAL;
216 goto out_unlock;
217 }
218
219 ret = drm_set_master(dev, file_priv, false);
220 kprintf("drm_setmaster_ioctl: fall-through set master ret=%d\n", ret);
221 out_unlock:
222 mutex_unlock(&dev->master_mutex);
223 return ret;
224 }
225
drm_drop_master(struct drm_device * dev,struct drm_file * fpriv)226 static void drm_drop_master(struct drm_device *dev,
227 struct drm_file *fpriv)
228 {
229 if (dev->driver->master_drop)
230 dev->driver->master_drop(dev, fpriv);
231 drm_master_put(&dev->master);
232 }
233
drm_dropmaster_ioctl(struct drm_device * dev,void * data,struct drm_file * file_priv)234 int drm_dropmaster_ioctl(struct drm_device *dev, void *data,
235 struct drm_file *file_priv)
236 {
237 int ret = -EINVAL;
238
239 kprintf("drm_dropmaster_ioctl\n");
240 mutex_lock(&dev->master_mutex);
241 if (!drm_is_current_master(file_priv))
242 goto out_unlock;
243
244 if (!dev->master)
245 goto out_unlock;
246
247 if (file_priv->master->lessor != NULL) {
248 DRM_DEBUG_LEASE("Attempt to drop lessee %d as master\n", file_priv->master->lessee_id);
249 ret = -EINVAL;
250 goto out_unlock;
251 }
252
253 ret = 0;
254 drm_drop_master(dev, file_priv);
255 out_unlock:
256 mutex_unlock(&dev->master_mutex);
257 return ret;
258 }
259
drm_master_open(struct drm_file * file_priv)260 int drm_master_open(struct drm_file *file_priv)
261 {
262 struct drm_device *dev = file_priv->minor->dev;
263 int ret = 0;
264
265 /* if there is no current master make this fd it, but do not create
266 * any master object for render clients */
267 mutex_lock(&dev->master_mutex);
268 if (!dev->master)
269 ret = drm_new_set_master(dev, file_priv);
270 else
271 file_priv->master = drm_master_get(dev->master);
272 mutex_unlock(&dev->master_mutex);
273
274 return ret;
275 }
276
drm_master_release(struct drm_file * file_priv)277 void drm_master_release(struct drm_file *file_priv)
278 {
279 struct drm_device *dev = file_priv->minor->dev;
280 struct drm_master *master = file_priv->master;
281
282 mutex_lock(&dev->master_mutex);
283 if (file_priv->magic)
284 idr_remove(&file_priv->master->magic_map, file_priv->magic);
285
286 if (!drm_is_current_master(file_priv))
287 goto out;
288
289 if (drm_core_check_feature(dev, DRIVER_LEGACY)) {
290 /*
291 * Since the master is disappearing, so is the
292 * possibility to lock.
293 */
294 mutex_lock(&dev->struct_mutex);
295 if (master->lock.hw_lock) {
296 if (dev->sigdata.lock == master->lock.hw_lock)
297 dev->sigdata.lock = NULL;
298 master->lock.hw_lock = NULL;
299 master->lock.file_priv = NULL;
300 wake_up_interruptible_all(&master->lock.lock_queue);
301 }
302 mutex_unlock(&dev->struct_mutex);
303 }
304
305 if (dev->master == file_priv->master)
306 drm_drop_master(dev, file_priv);
307 out:
308 if (drm_core_check_feature(dev, DRIVER_MODESET) && file_priv->is_master) {
309 /* Revoke any leases held by this or lessees, but only if
310 * this is the "real" master
311 */
312 drm_lease_revoke(master);
313 }
314
315 /* drop the master reference held by the file priv */
316 if (file_priv->master)
317 drm_master_put(&file_priv->master);
318 mutex_unlock(&dev->master_mutex);
319 }
320
321 /**
322 * drm_is_current_master - checks whether @priv is the current master
323 * @fpriv: DRM file private
324 *
325 * Checks whether @fpriv is current master on its device. This decides whether a
326 * client is allowed to run DRM_MASTER IOCTLs.
327 *
328 * Most of the modern IOCTL which require DRM_MASTER are for kernel modesetting
329 * - the current master is assumed to own the non-shareable display hardware.
330 */
drm_is_current_master(struct drm_file * fpriv)331 bool drm_is_current_master(struct drm_file *fpriv)
332 {
333 return fpriv->is_master;
334 }
335 EXPORT_SYMBOL(drm_is_current_master);
336
337 /**
338 * drm_master_get - reference a master pointer
339 * @master: &struct drm_master
340 *
341 * Increments the reference count of @master and returns a pointer to @master.
342 */
drm_master_get(struct drm_master * master)343 struct drm_master *drm_master_get(struct drm_master *master)
344 {
345 kref_get(&master->refcount);
346 return master;
347 }
348 EXPORT_SYMBOL(drm_master_get);
349
drm_master_destroy(struct kref * kref)350 static void drm_master_destroy(struct kref *kref)
351 {
352 struct drm_master *master = container_of(kref, struct drm_master, refcount);
353 struct drm_device *dev = master->dev;
354
355 if (drm_core_check_feature(dev, DRIVER_MODESET))
356 drm_lease_destroy(master);
357
358 if (dev->driver->master_destroy)
359 dev->driver->master_destroy(dev, master);
360
361 drm_legacy_master_rmmaps(dev, master);
362
363 idr_destroy(&master->magic_map);
364 idr_destroy(&master->leases);
365 idr_destroy(&master->lessee_idr);
366
367 kfree(master->unique);
368 kfree(master);
369 }
370
371 /**
372 * drm_master_put - unreference and clear a master pointer
373 * @master: pointer to a pointer of &struct drm_master
374 *
375 * This decrements the &drm_master behind @master and sets it to NULL.
376 */
drm_master_put(struct drm_master ** master)377 void drm_master_put(struct drm_master **master)
378 {
379 kref_put(&(*master)->refcount, drm_master_destroy);
380 *master = NULL;
381 }
382 EXPORT_SYMBOL(drm_master_put);
383