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 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 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 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 spin_lock_init(&master->lock.spinlock); 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 } 121 122 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 } 137 138 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 lockdep_assert_held_once(&dev->master_mutex); 144 145 old_master = fpriv->master; 146 fpriv->master = drm_master_create(dev); 147 if (!fpriv->master) { 148 fpriv->master = old_master; 149 return -ENOMEM; 150 } 151 152 if (dev->driver->master_create) { 153 ret = dev->driver->master_create(dev, fpriv->master); 154 if (ret) 155 goto out_err; 156 } 157 fpriv->is_master = 1; 158 fpriv->authenticated = 1; 159 160 ret = drm_set_master(dev, fpriv, true); 161 if (ret) 162 goto out_err; 163 164 if (old_master) 165 drm_master_put(&old_master); 166 167 return 0; 168 169 out_err: 170 /* drop references and restore old master on failure */ 171 drm_master_put(&fpriv->master); 172 fpriv->master = old_master; 173 174 return ret; 175 } 176 177 int drm_setmaster_ioctl(struct drm_device *dev, void *data, 178 struct drm_file *file_priv) 179 { 180 int ret = 0; 181 182 mutex_lock(&dev->master_mutex); 183 if (drm_is_current_master(file_priv)) 184 goto out_unlock; 185 186 if (dev->master) { 187 ret = -EINVAL; 188 goto out_unlock; 189 } 190 191 if (!file_priv->master) { 192 ret = -EINVAL; 193 goto out_unlock; 194 } 195 196 if (!file_priv->is_master) { 197 ret = drm_new_set_master(dev, file_priv); 198 goto out_unlock; 199 } 200 201 if (file_priv->master->lessor != NULL) { 202 DRM_DEBUG_LEASE("Attempt to set lessee %d as master\n", file_priv->master->lessee_id); 203 ret = -EINVAL; 204 goto out_unlock; 205 } 206 207 ret = drm_set_master(dev, file_priv, false); 208 out_unlock: 209 mutex_unlock(&dev->master_mutex); 210 return ret; 211 } 212 213 static void drm_drop_master(struct drm_device *dev, 214 struct drm_file *fpriv) 215 { 216 if (dev->driver->master_drop) 217 dev->driver->master_drop(dev, fpriv); 218 drm_master_put(&dev->master); 219 } 220 221 int drm_dropmaster_ioctl(struct drm_device *dev, void *data, 222 struct drm_file *file_priv) 223 { 224 int ret = -EINVAL; 225 226 mutex_lock(&dev->master_mutex); 227 if (!drm_is_current_master(file_priv)) 228 goto out_unlock; 229 230 if (!dev->master) 231 goto out_unlock; 232 233 if (file_priv->master->lessor != NULL) { 234 DRM_DEBUG_LEASE("Attempt to drop lessee %d as master\n", file_priv->master->lessee_id); 235 ret = -EINVAL; 236 goto out_unlock; 237 } 238 239 ret = 0; 240 drm_drop_master(dev, file_priv); 241 out_unlock: 242 mutex_unlock(&dev->master_mutex); 243 return ret; 244 } 245 246 int drm_master_open(struct drm_file *file_priv) 247 { 248 struct drm_device *dev = file_priv->minor->dev; 249 int ret = 0; 250 251 /* if there is no current master make this fd it, but do not create 252 * any master object for render clients */ 253 mutex_lock(&dev->master_mutex); 254 if (!dev->master) 255 ret = drm_new_set_master(dev, file_priv); 256 else 257 file_priv->master = drm_master_get(dev->master); 258 mutex_unlock(&dev->master_mutex); 259 260 return ret; 261 } 262 263 void drm_master_release(struct drm_file *file_priv) 264 { 265 struct drm_device *dev = file_priv->minor->dev; 266 struct drm_master *master = file_priv->master; 267 268 mutex_lock(&dev->master_mutex); 269 if (file_priv->magic) 270 idr_remove(&file_priv->master->magic_map, file_priv->magic); 271 272 if (!drm_is_current_master(file_priv)) 273 goto out; 274 275 if (drm_core_check_feature(dev, DRIVER_LEGACY)) { 276 /* 277 * Since the master is disappearing, so is the 278 * possibility to lock. 279 */ 280 mutex_lock(&dev->struct_mutex); 281 if (master->lock.hw_lock) { 282 if (dev->sigdata.lock == master->lock.hw_lock) 283 dev->sigdata.lock = NULL; 284 master->lock.hw_lock = NULL; 285 master->lock.file_priv = NULL; 286 wake_up_interruptible_all(&master->lock.lock_queue); 287 } 288 mutex_unlock(&dev->struct_mutex); 289 } 290 291 if (dev->master == file_priv->master) 292 drm_drop_master(dev, file_priv); 293 out: 294 if (drm_core_check_feature(dev, DRIVER_MODESET) && file_priv->is_master) { 295 /* Revoke any leases held by this or lessees, but only if 296 * this is the "real" master 297 */ 298 drm_lease_revoke(master); 299 } 300 301 /* drop the master reference held by the file priv */ 302 if (file_priv->master) 303 drm_master_put(&file_priv->master); 304 mutex_unlock(&dev->master_mutex); 305 } 306 307 /** 308 * drm_is_current_master - checks whether @priv is the current master 309 * @fpriv: DRM file private 310 * 311 * Checks whether @fpriv is current master on its device. This decides whether a 312 * client is allowed to run DRM_MASTER IOCTLs. 313 * 314 * Most of the modern IOCTL which require DRM_MASTER are for kernel modesetting 315 * - the current master is assumed to own the non-shareable display hardware. 316 */ 317 bool drm_is_current_master(struct drm_file *fpriv) 318 { 319 return fpriv->is_master && drm_lease_owner(fpriv->master) == fpriv->minor->dev->master; 320 } 321 EXPORT_SYMBOL(drm_is_current_master); 322 323 /** 324 * drm_master_get - reference a master pointer 325 * @master: &struct drm_master 326 * 327 * Increments the reference count of @master and returns a pointer to @master. 328 */ 329 struct drm_master *drm_master_get(struct drm_master *master) 330 { 331 kref_get(&master->refcount); 332 return master; 333 } 334 EXPORT_SYMBOL(drm_master_get); 335 336 static void drm_master_destroy(struct kref *kref) 337 { 338 struct drm_master *master = container_of(kref, struct drm_master, refcount); 339 struct drm_device *dev = master->dev; 340 341 if (drm_core_check_feature(dev, DRIVER_MODESET)) 342 drm_lease_destroy(master); 343 344 if (dev->driver->master_destroy) 345 dev->driver->master_destroy(dev, master); 346 347 drm_legacy_master_rmmaps(dev, master); 348 349 idr_destroy(&master->magic_map); 350 idr_destroy(&master->leases); 351 idr_destroy(&master->lessee_idr); 352 353 kfree(master->unique); 354 kfree(master); 355 } 356 357 /** 358 * drm_master_put - unreference and clear a master pointer 359 * @master: pointer to a pointer of &struct drm_master 360 * 361 * This decrements the &drm_master behind @master and sets it to NULL. 362 */ 363 void drm_master_put(struct drm_master **master) 364 { 365 kref_put(&(*master)->refcount, drm_master_destroy); 366 *master = NULL; 367 } 368 EXPORT_SYMBOL(drm_master_put); 369