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 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 } 121 122 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 #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 } 178 179 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 if (dev->master) { 189 ret = -EINVAL; 190 goto out_unlock; 191 } 192 193 if (!file_priv->master) { 194 ret = -EINVAL; 195 goto out_unlock; 196 } 197 198 if (!file_priv->is_master) { 199 ret = drm_new_set_master(dev, file_priv); 200 goto out_unlock; 201 } 202 203 if (file_priv->master->lessor != NULL) { 204 DRM_DEBUG_LEASE("Attempt to set lessee %d as master\n", file_priv->master->lessee_id); 205 ret = -EINVAL; 206 goto out_unlock; 207 } 208 209 ret = drm_set_master(dev, file_priv, false); 210 out_unlock: 211 mutex_unlock(&dev->master_mutex); 212 return ret; 213 } 214 215 static void drm_drop_master(struct drm_device *dev, 216 struct drm_file *fpriv) 217 { 218 if (dev->driver->master_drop) 219 dev->driver->master_drop(dev, fpriv); 220 drm_master_put(&dev->master); 221 } 222 223 int drm_dropmaster_ioctl(struct drm_device *dev, void *data, 224 struct drm_file *file_priv) 225 { 226 int ret = -EINVAL; 227 228 mutex_lock(&dev->master_mutex); 229 if (!drm_is_current_master(file_priv)) 230 goto out_unlock; 231 232 if (!dev->master) 233 goto out_unlock; 234 235 if (file_priv->master->lessor != NULL) { 236 DRM_DEBUG_LEASE("Attempt to drop lessee %d as master\n", file_priv->master->lessee_id); 237 ret = -EINVAL; 238 goto out_unlock; 239 } 240 241 ret = 0; 242 drm_drop_master(dev, file_priv); 243 out_unlock: 244 mutex_unlock(&dev->master_mutex); 245 return ret; 246 } 247 248 int drm_master_open(struct drm_file *file_priv) 249 { 250 struct drm_device *dev = file_priv->minor->dev; 251 int ret = 0; 252 253 /* if there is no current master make this fd it, but do not create 254 * any master object for render clients */ 255 mutex_lock(&dev->master_mutex); 256 if (!dev->master) 257 ret = drm_new_set_master(dev, file_priv); 258 else 259 file_priv->master = drm_master_get(dev->master); 260 mutex_unlock(&dev->master_mutex); 261 262 return ret; 263 } 264 265 void drm_master_release(struct drm_file *file_priv) 266 { 267 struct drm_device *dev = file_priv->minor->dev; 268 struct drm_master *master = file_priv->master; 269 270 mutex_lock(&dev->master_mutex); 271 if (file_priv->magic) 272 idr_remove(&file_priv->master->magic_map, file_priv->magic); 273 274 if (!drm_is_current_master(file_priv)) 275 goto out; 276 277 if (drm_core_check_feature(dev, DRIVER_LEGACY)) { 278 /* 279 * Since the master is disappearing, so is the 280 * possibility to lock. 281 */ 282 mutex_lock(&dev->struct_mutex); 283 if (master->lock.hw_lock) { 284 if (dev->sigdata.lock == master->lock.hw_lock) 285 dev->sigdata.lock = NULL; 286 master->lock.hw_lock = NULL; 287 master->lock.file_priv = NULL; 288 wake_up_interruptible_all(&master->lock.lock_queue); 289 } 290 mutex_unlock(&dev->struct_mutex); 291 } 292 293 if (dev->master == file_priv->master) 294 drm_drop_master(dev, file_priv); 295 out: 296 if (drm_core_check_feature(dev, DRIVER_MODESET) && file_priv->is_master) { 297 /* Revoke any leases held by this or lessees, but only if 298 * this is the "real" master 299 */ 300 drm_lease_revoke(master); 301 } 302 303 /* drop the master reference held by the file priv */ 304 if (file_priv->master) 305 drm_master_put(&file_priv->master); 306 mutex_unlock(&dev->master_mutex); 307 } 308 309 /** 310 * drm_is_current_master - checks whether @priv is the current master 311 * @fpriv: DRM file private 312 * 313 * Checks whether @fpriv is current master on its device. This decides whether a 314 * client is allowed to run DRM_MASTER IOCTLs. 315 * 316 * Most of the modern IOCTL which require DRM_MASTER are for kernel modesetting 317 * - the current master is assumed to own the non-shareable display hardware. 318 */ 319 bool drm_is_current_master(struct drm_file *fpriv) 320 { 321 return fpriv->is_master; 322 } 323 EXPORT_SYMBOL(drm_is_current_master); 324 325 /** 326 * drm_master_get - reference a master pointer 327 * @master: &struct drm_master 328 * 329 * Increments the reference count of @master and returns a pointer to @master. 330 */ 331 struct drm_master *drm_master_get(struct drm_master *master) 332 { 333 kref_get(&master->refcount); 334 return master; 335 } 336 EXPORT_SYMBOL(drm_master_get); 337 338 static void drm_master_destroy(struct kref *kref) 339 { 340 struct drm_master *master = container_of(kref, struct drm_master, refcount); 341 struct drm_device *dev = master->dev; 342 343 if (drm_core_check_feature(dev, DRIVER_MODESET)) 344 drm_lease_destroy(master); 345 346 if (dev->driver->master_destroy) 347 dev->driver->master_destroy(dev, master); 348 349 drm_legacy_master_rmmaps(dev, master); 350 351 idr_destroy(&master->magic_map); 352 idr_destroy(&master->leases); 353 idr_destroy(&master->lessee_idr); 354 355 kfree(master->unique); 356 kfree(master); 357 } 358 359 /** 360 * drm_master_put - unreference and clear a master pointer 361 * @master: pointer to a pointer of &struct drm_master 362 * 363 * This decrements the &drm_master behind @master and sets it to NULL. 364 */ 365 void drm_master_put(struct drm_master **master) 366 { 367 kref_put(&(*master)->refcount, drm_master_destroy); 368 *master = NULL; 369 } 370 EXPORT_SYMBOL(drm_master_put); 371