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 drm_master_legacy_init(master); 107 idr_init(&master->magic_map); 108 master->dev = dev; 109 110 /* initialize the tree of output resource lessees */ 111 INIT_LIST_HEAD(&master->lessees); 112 INIT_LIST_HEAD(&master->lessee_list); 113 idr_init(&master->leases); 114 idr_init(&master->lessee_idr); 115 116 return master; 117 } 118 119 static int drm_set_master(struct drm_device *dev, struct drm_file *fpriv, 120 bool new_master) 121 { 122 int ret = 0; 123 124 dev->master = drm_master_get(fpriv->master); 125 if (dev->driver->master_set) { 126 ret = dev->driver->master_set(dev, fpriv, new_master); 127 if (unlikely(ret != 0)) { 128 drm_master_put(&dev->master); 129 } 130 } 131 132 return ret; 133 } 134 135 static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv) 136 { 137 struct drm_master *old_master; 138 int ret; 139 140 lockdep_assert_held_once(&dev->master_mutex); 141 142 WARN_ON(fpriv->is_master); 143 old_master = fpriv->master; 144 fpriv->master = drm_master_create(dev); 145 if (!fpriv->master) { 146 fpriv->master = old_master; 147 return -ENOMEM; 148 } 149 150 if (dev->driver->master_create) { 151 ret = dev->driver->master_create(dev, fpriv->master); 152 if (ret) 153 goto out_err; 154 } 155 fpriv->is_master = 1; 156 fpriv->authenticated = 1; 157 158 ret = drm_set_master(dev, fpriv, true); 159 if (ret) 160 goto out_err; 161 162 if (old_master) 163 drm_master_put(&old_master); 164 165 return 0; 166 167 out_err: 168 /* drop references and restore old master on failure */ 169 drm_master_put(&fpriv->master); 170 fpriv->master = old_master; 171 fpriv->is_master = 0; 172 173 return ret; 174 } 175 176 int drm_setmaster_ioctl(struct drm_device *dev, void *data, 177 struct drm_file *file_priv) 178 { 179 int ret = 0; 180 181 mutex_lock(&dev->master_mutex); 182 if (drm_is_current_master(file_priv)) 183 goto out_unlock; 184 185 if (dev->master) { 186 ret = -EINVAL; 187 goto out_unlock; 188 } 189 190 if (!file_priv->master) { 191 ret = -EINVAL; 192 goto out_unlock; 193 } 194 195 if (!file_priv->is_master) { 196 ret = drm_new_set_master(dev, file_priv); 197 goto out_unlock; 198 } 199 200 if (file_priv->master->lessor != NULL) { 201 DRM_DEBUG_LEASE("Attempt to set lessee %d as master\n", file_priv->master->lessee_id); 202 ret = -EINVAL; 203 goto out_unlock; 204 } 205 206 ret = drm_set_master(dev, file_priv, false); 207 out_unlock: 208 mutex_unlock(&dev->master_mutex); 209 return ret; 210 } 211 212 static void drm_drop_master(struct drm_device *dev, 213 struct drm_file *fpriv) 214 { 215 if (dev->driver->master_drop) 216 dev->driver->master_drop(dev, fpriv); 217 drm_master_put(&dev->master); 218 } 219 220 int drm_dropmaster_ioctl(struct drm_device *dev, void *data, 221 struct drm_file *file_priv) 222 { 223 int ret = -EINVAL; 224 225 mutex_lock(&dev->master_mutex); 226 if (!drm_is_current_master(file_priv)) 227 goto out_unlock; 228 229 if (!dev->master) 230 goto out_unlock; 231 232 if (file_priv->master->lessor != NULL) { 233 DRM_DEBUG_LEASE("Attempt to drop lessee %d as master\n", file_priv->master->lessee_id); 234 ret = -EINVAL; 235 goto out_unlock; 236 } 237 238 ret = 0; 239 drm_drop_master(dev, file_priv); 240 out_unlock: 241 mutex_unlock(&dev->master_mutex); 242 return ret; 243 } 244 245 int drm_master_open(struct drm_file *file_priv) 246 { 247 struct drm_device *dev = file_priv->minor->dev; 248 int ret = 0; 249 250 /* if there is no current master make this fd it, but do not create 251 * any master object for render clients */ 252 mutex_lock(&dev->master_mutex); 253 if (!dev->master) 254 ret = drm_new_set_master(dev, file_priv); 255 else 256 file_priv->master = drm_master_get(dev->master); 257 mutex_unlock(&dev->master_mutex); 258 259 return ret; 260 } 261 262 void drm_master_release(struct drm_file *file_priv) 263 { 264 struct drm_device *dev = file_priv->minor->dev; 265 struct drm_master *master = file_priv->master; 266 267 mutex_lock(&dev->master_mutex); 268 if (file_priv->magic) 269 idr_remove(&file_priv->master->magic_map, file_priv->magic); 270 271 if (!drm_is_current_master(file_priv)) 272 goto out; 273 274 drm_legacy_lock_master_cleanup(dev, master); 275 276 if (dev->master == file_priv->master) 277 drm_drop_master(dev, file_priv); 278 out: 279 if (drm_core_check_feature(dev, DRIVER_MODESET) && file_priv->is_master) { 280 /* Revoke any leases held by this or lessees, but only if 281 * this is the "real" master 282 */ 283 drm_lease_revoke(master); 284 } 285 286 /* drop the master reference held by the file priv */ 287 if (file_priv->master) 288 drm_master_put(&file_priv->master); 289 mutex_unlock(&dev->master_mutex); 290 } 291 292 /** 293 * drm_is_current_master - checks whether @priv is the current master 294 * @fpriv: DRM file private 295 * 296 * Checks whether @fpriv is current master on its device. This decides whether a 297 * client is allowed to run DRM_MASTER IOCTLs. 298 * 299 * Most of the modern IOCTL which require DRM_MASTER are for kernel modesetting 300 * - the current master is assumed to own the non-shareable display hardware. 301 */ 302 bool drm_is_current_master(struct drm_file *fpriv) 303 { 304 return fpriv->is_master && drm_lease_owner(fpriv->master) == fpriv->minor->dev->master; 305 } 306 EXPORT_SYMBOL(drm_is_current_master); 307 308 /** 309 * drm_master_get - reference a master pointer 310 * @master: &struct drm_master 311 * 312 * Increments the reference count of @master and returns a pointer to @master. 313 */ 314 struct drm_master *drm_master_get(struct drm_master *master) 315 { 316 kref_get(&master->refcount); 317 return master; 318 } 319 EXPORT_SYMBOL(drm_master_get); 320 321 static void drm_master_destroy(struct kref *kref) 322 { 323 struct drm_master *master = container_of(kref, struct drm_master, refcount); 324 struct drm_device *dev = master->dev; 325 326 if (drm_core_check_feature(dev, DRIVER_MODESET)) 327 drm_lease_destroy(master); 328 329 if (dev->driver->master_destroy) 330 dev->driver->master_destroy(dev, master); 331 332 drm_legacy_master_rmmaps(dev, master); 333 334 idr_destroy(&master->magic_map); 335 idr_destroy(&master->leases); 336 idr_destroy(&master->lessee_idr); 337 338 kfree(master->unique); 339 kfree(master); 340 } 341 342 /** 343 * drm_master_put - unreference and clear a master pointer 344 * @master: pointer to a pointer of &struct drm_master 345 * 346 * This decrements the &drm_master behind @master and sets it to NULL. 347 */ 348 void drm_master_put(struct drm_master **master) 349 { 350 kref_put(&(*master)->refcount, drm_master_destroy); 351 *master = NULL; 352 } 353 EXPORT_SYMBOL(drm_master_put); 354