2 * Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com
4 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
5 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
8 * Author Rickard E. (Rik) Faith <faith@valinux.com>
9 * Author Gareth Hughes <gareth@valinux.com>
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:
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
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.
32 #include "drm_internal.h"
33 #include "drm_legacy.h"
36 * DOC: master and authentication
38 * struct &drm_master is used to track groups of clients with open
39 * primary/legacy device nodes. For every struct &drm_file which has had at
40 * least once successfully became the device master (either through the
41 * SET_MASTER IOCTL, or implicitly through opening the primary device node when
42 * no one else is the current master that time) there exists one &drm_master.
43 * This is noted in the is_master member of &drm_file. All other clients have
44 * just a pointer to the &drm_master they are associated with.
46 * In addition only one &drm_master can be the current master for a &drm_device.
47 * It can be switched through the DROP_MASTER and SET_MASTER IOCTL, or
48 * implicitly through closing/openeing the primary device node. See also
49 * drm_is_current_master().
51 * Clients can authenticate against the current master (if it matches their own)
52 * using the GETMAGIC and AUTHMAGIC IOCTLs. Together with exchanging masters,
53 * this allows controlled access to the device for an entire group of mutually
57 int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv)
59 struct drm_auth *auth = data;
62 mutex_lock(&dev->master_mutex);
63 if (!file_priv->magic) {
64 ret = idr_alloc(&file_priv->master->magic_map, file_priv,
67 file_priv->magic = ret;
69 auth->magic = file_priv->magic;
70 mutex_unlock(&dev->master_mutex);
72 DRM_DEBUG("%u\n", auth->magic);
74 return ret < 0 ? ret : 0;
77 int drm_authmagic(struct drm_device *dev, void *data,
78 struct drm_file *file_priv)
80 struct drm_auth *auth = data;
81 struct drm_file *file;
83 DRM_DEBUG("%u\n", auth->magic);
85 mutex_lock(&dev->master_mutex);
86 file = idr_find(&file_priv->master->magic_map, auth->magic);
88 file->authenticated = 1;
89 idr_replace(&file_priv->master->magic_map, NULL, auth->magic);
91 mutex_unlock(&dev->master_mutex);
93 return file ? 0 : -EINVAL;
96 static struct drm_master *drm_master_create(struct drm_device *dev)
98 struct drm_master *master;
100 master = kzalloc(sizeof(*master), GFP_KERNEL);
104 kref_init(&master->refcount);
105 spin_lock_init(&master->lock.spinlock);
106 init_waitqueue_head(&master->lock.lock_queue);
107 idr_init(&master->magic_map);
113 static int drm_set_master(struct drm_device *dev, struct drm_file *fpriv,
118 dev->master = drm_master_get(fpriv->master);
119 if (dev->driver->master_set) {
120 ret = dev->driver->master_set(dev, fpriv, new_master);
121 if (unlikely(ret != 0)) {
122 drm_master_put(&dev->master);
129 static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv)
131 struct drm_master *old_master;
134 lockdep_assert_held_once(&dev->master_mutex);
136 WARN_ON(fpriv->is_master);
137 old_master = fpriv->master;
138 fpriv->master = drm_master_create(dev);
139 if (!fpriv->master) {
140 fpriv->master = old_master;
144 if (dev->driver->master_create) {
145 ret = dev->driver->master_create(dev, fpriv->master);
149 fpriv->is_master = 1;
150 fpriv->authenticated = 1;
152 ret = drm_set_master(dev, fpriv, true);
157 drm_master_put(&old_master);
162 /* drop references and restore old master on failure */
163 drm_master_put(&fpriv->master);
164 fpriv->master = old_master;
165 fpriv->is_master = 0;
170 int drm_setmaster_ioctl(struct drm_device *dev, void *data,
171 struct drm_file *file_priv)
175 mutex_lock(&dev->master_mutex);
176 if (drm_is_current_master(file_priv))
184 if (!file_priv->master) {
189 if (!file_priv->is_master) {
190 ret = drm_new_set_master(dev, file_priv);
194 ret = drm_set_master(dev, file_priv, false);
196 mutex_unlock(&dev->master_mutex);
200 static void drm_drop_master(struct drm_device *dev,
201 struct drm_file *fpriv)
203 if (dev->driver->master_drop)
204 dev->driver->master_drop(dev, fpriv);
205 drm_master_put(&dev->master);
208 int drm_dropmaster_ioctl(struct drm_device *dev, void *data,
209 struct drm_file *file_priv)
213 mutex_lock(&dev->master_mutex);
214 if (!drm_is_current_master(file_priv))
221 drm_drop_master(dev, file_priv);
223 mutex_unlock(&dev->master_mutex);
227 int drm_master_open(struct drm_file *file_priv)
229 struct drm_device *dev = file_priv->minor->dev;
232 /* if there is no current master make this fd it, but do not create
233 * any master object for render clients */
234 mutex_lock(&dev->master_mutex);
236 ret = drm_new_set_master(dev, file_priv);
238 file_priv->master = drm_master_get(dev->master);
239 mutex_unlock(&dev->master_mutex);
244 void drm_master_release(struct drm_file *file_priv)
246 struct drm_device *dev = file_priv->minor->dev;
247 struct drm_master *master;
249 mutex_lock(&dev->master_mutex);
250 master = file_priv->master;
251 if (file_priv->magic)
252 idr_remove(&file_priv->master->magic_map, file_priv->magic);
254 if (!drm_is_current_master(file_priv))
257 if (drm_core_check_feature(dev, DRIVER_LEGACY)) {
259 * Since the master is disappearing, so is the
260 * possibility to lock.
262 mutex_lock(&dev->struct_mutex);
263 if (master->lock.hw_lock) {
264 if (dev->sigdata.lock == master->lock.hw_lock)
265 dev->sigdata.lock = NULL;
266 master->lock.hw_lock = NULL;
267 master->lock.file_priv = NULL;
268 wake_up_interruptible_all(&master->lock.lock_queue);
270 mutex_unlock(&dev->struct_mutex);
273 if (dev->master == file_priv->master)
274 drm_drop_master(dev, file_priv);
276 /* drop the master reference held by the file priv */
277 if (file_priv->master)
278 drm_master_put(&file_priv->master);
279 mutex_unlock(&dev->master_mutex);
283 * drm_is_current_master - checks whether @priv is the current master
284 * @fpriv: DRM file private
286 * Checks whether @fpriv is current master on its device. This decides whether a
287 * client is allowed to run DRM_MASTER IOCTLs.
289 * Most of the modern IOCTL which require DRM_MASTER are for kernel modesetting
290 * - the current master is assumed to own the non-shareable display hardware.
292 bool drm_is_current_master(struct drm_file *fpriv)
294 return fpriv->is_master && fpriv->master == fpriv->minor->dev->master;
296 EXPORT_SYMBOL(drm_is_current_master);
299 * drm_master_get - reference a master pointer
300 * @master: struct &drm_master
302 * Increments the reference count of @master and returns a pointer to @master.
304 struct drm_master *drm_master_get(struct drm_master *master)
306 kref_get(&master->refcount);
309 EXPORT_SYMBOL(drm_master_get);
311 static void drm_master_destroy(struct kref *kref)
313 struct drm_master *master = container_of(kref, struct drm_master, refcount);
314 struct drm_device *dev = master->dev;
316 if (dev->driver->master_destroy)
317 dev->driver->master_destroy(dev, master);
319 drm_legacy_master_rmmaps(dev, master);
321 idr_destroy(&master->magic_map);
322 kfree(master->unique);
327 * drm_master_put - unreference and clear a master pointer
328 * @master: pointer to a pointer of struct &drm_master
330 * This decrements the &drm_master behind @master and sets it to NULL.
332 void drm_master_put(struct drm_master **master)
334 kref_put(&(*master)->refcount, drm_master_destroy);
337 EXPORT_SYMBOL(drm_master_put);