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 <linux/slab.h> 32 33 #include <drm/drm_auth.h> 34 #include <drm/drm_drv.h> 35 #include <drm/drm_file.h> 36 #include <drm/drm_lease.h> 37 #include <drm/drm_print.h> 38 39 #include "drm_internal.h" 40 #include "drm_legacy.h" 41 42 /** 43 * DOC: master and authentication 44 * 45 * &struct drm_master is used to track groups of clients with open 46 * primary/legacy device nodes. For every &struct drm_file which has had at 47 * least once successfully became the device master (either through the 48 * SET_MASTER IOCTL, or implicitly through opening the primary device node when 49 * no one else is the current master that time) there exists one &drm_master. 50 * This is noted in &drm_file.is_master. All other clients have just a pointer 51 * to the &drm_master they are associated with. 52 * 53 * In addition only one &drm_master can be the current master for a &drm_device. 54 * It can be switched through the DROP_MASTER and SET_MASTER IOCTL, or 55 * implicitly through closing/openeing the primary device node. See also 56 * drm_is_current_master(). 57 * 58 * Clients can authenticate against the current master (if it matches their own) 59 * using the GETMAGIC and AUTHMAGIC IOCTLs. Together with exchanging masters, 60 * this allows controlled access to the device for an entire group of mutually 61 * trusted clients. 62 */ 63 64 int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv) 65 { 66 struct drm_auth *auth = data; 67 int ret = 0; 68 69 mutex_lock(&dev->master_mutex); 70 if (!file_priv->magic) { 71 ret = idr_alloc(&file_priv->master->magic_map, file_priv, 72 1, 0, GFP_KERNEL); 73 if (ret >= 0) 74 file_priv->magic = ret; 75 } 76 auth->magic = file_priv->magic; 77 mutex_unlock(&dev->master_mutex); 78 79 DRM_DEBUG("%u\n", auth->magic); 80 81 return ret < 0 ? ret : 0; 82 } 83 84 int drm_authmagic(struct drm_device *dev, void *data, 85 struct drm_file *file_priv) 86 { 87 struct drm_auth *auth = data; 88 struct drm_file *file; 89 90 DRM_DEBUG("%u\n", auth->magic); 91 92 mutex_lock(&dev->master_mutex); 93 file = idr_find(&file_priv->master->magic_map, auth->magic); 94 if (file) { 95 file->authenticated = 1; 96 idr_replace(&file_priv->master->magic_map, NULL, auth->magic); 97 } 98 mutex_unlock(&dev->master_mutex); 99 100 return file ? 0 : -EINVAL; 101 } 102 103 struct drm_master *drm_master_create(struct drm_device *dev) 104 { 105 struct drm_master *master; 106 107 master = kzalloc(sizeof(*master), GFP_KERNEL); 108 if (!master) 109 return NULL; 110 111 kref_init(&master->refcount); 112 drm_master_legacy_init(master); 113 idr_init(&master->magic_map); 114 master->dev = dev; 115 116 /* initialize the tree of output resource lessees */ 117 INIT_LIST_HEAD(&master->lessees); 118 INIT_LIST_HEAD(&master->lessee_list); 119 idr_init(&master->leases); 120 idr_init(&master->lessee_idr); 121 122 return master; 123 } 124 125 static int drm_set_master(struct drm_device *dev, struct drm_file *fpriv, 126 bool new_master) 127 { 128 int ret = 0; 129 130 dev->master = drm_master_get(fpriv->master); 131 if (dev->driver->master_set) { 132 ret = dev->driver->master_set(dev, fpriv, new_master); 133 if (unlikely(ret != 0)) { 134 drm_master_put(&dev->master); 135 } 136 } 137 138 return ret; 139 } 140 141 static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv) 142 { 143 struct drm_master *old_master; 144 int ret; 145 146 lockdep_assert_held_once(&dev->master_mutex); 147 148 WARN_ON(fpriv->is_master); 149 old_master = fpriv->master; 150 fpriv->master = drm_master_create(dev); 151 if (!fpriv->master) { 152 fpriv->master = old_master; 153 return -ENOMEM; 154 } 155 156 if (dev->driver->master_create) { 157 ret = dev->driver->master_create(dev, fpriv->master); 158 if (ret) 159 goto out_err; 160 } 161 fpriv->is_master = 1; 162 fpriv->authenticated = 1; 163 164 ret = drm_set_master(dev, fpriv, true); 165 if (ret) 166 goto out_err; 167 168 if (old_master) 169 drm_master_put(&old_master); 170 171 return 0; 172 173 out_err: 174 /* drop references and restore old master on failure */ 175 drm_master_put(&fpriv->master); 176 fpriv->master = old_master; 177 fpriv->is_master = 0; 178 179 return ret; 180 } 181 182 int drm_setmaster_ioctl(struct drm_device *dev, void *data, 183 struct drm_file *file_priv) 184 { 185 int ret = 0; 186 187 mutex_lock(&dev->master_mutex); 188 if (drm_is_current_master(file_priv)) 189 goto out_unlock; 190 191 if (dev->master) { 192 ret = -EINVAL; 193 goto out_unlock; 194 } 195 196 if (!file_priv->master) { 197 ret = -EINVAL; 198 goto out_unlock; 199 } 200 201 if (!file_priv->is_master) { 202 ret = drm_new_set_master(dev, file_priv); 203 goto out_unlock; 204 } 205 206 if (file_priv->master->lessor != NULL) { 207 DRM_DEBUG_LEASE("Attempt to set lessee %d as master\n", file_priv->master->lessee_id); 208 ret = -EINVAL; 209 goto out_unlock; 210 } 211 212 ret = drm_set_master(dev, file_priv, false); 213 out_unlock: 214 mutex_unlock(&dev->master_mutex); 215 return ret; 216 } 217 218 static void drm_drop_master(struct drm_device *dev, 219 struct drm_file *fpriv) 220 { 221 if (dev->driver->master_drop) 222 dev->driver->master_drop(dev, fpriv); 223 drm_master_put(&dev->master); 224 } 225 226 int drm_dropmaster_ioctl(struct drm_device *dev, void *data, 227 struct drm_file *file_priv) 228 { 229 int ret = -EINVAL; 230 231 mutex_lock(&dev->master_mutex); 232 if (!drm_is_current_master(file_priv)) 233 goto out_unlock; 234 235 if (!dev->master) 236 goto out_unlock; 237 238 if (file_priv->master->lessor != NULL) { 239 DRM_DEBUG_LEASE("Attempt to drop lessee %d as master\n", file_priv->master->lessee_id); 240 ret = -EINVAL; 241 goto out_unlock; 242 } 243 244 ret = 0; 245 drm_drop_master(dev, file_priv); 246 out_unlock: 247 mutex_unlock(&dev->master_mutex); 248 return ret; 249 } 250 251 int drm_master_open(struct drm_file *file_priv) 252 { 253 struct drm_device *dev = file_priv->minor->dev; 254 int ret = 0; 255 256 /* if there is no current master make this fd it, but do not create 257 * any master object for render clients */ 258 mutex_lock(&dev->master_mutex); 259 if (!dev->master) 260 ret = drm_new_set_master(dev, file_priv); 261 else 262 file_priv->master = drm_master_get(dev->master); 263 mutex_unlock(&dev->master_mutex); 264 265 return ret; 266 } 267 268 void drm_master_release(struct drm_file *file_priv) 269 { 270 struct drm_device *dev = file_priv->minor->dev; 271 struct drm_master *master = file_priv->master; 272 273 mutex_lock(&dev->master_mutex); 274 if (file_priv->magic) 275 idr_remove(&file_priv->master->magic_map, file_priv->magic); 276 277 if (!drm_is_current_master(file_priv)) 278 goto out; 279 280 drm_legacy_lock_master_cleanup(dev, master); 281 282 if (dev->master == file_priv->master) 283 drm_drop_master(dev, file_priv); 284 out: 285 if (drm_core_check_feature(dev, DRIVER_MODESET) && file_priv->is_master) { 286 /* Revoke any leases held by this or lessees, but only if 287 * this is the "real" master 288 */ 289 drm_lease_revoke(master); 290 } 291 292 /* drop the master reference held by the file priv */ 293 if (file_priv->master) 294 drm_master_put(&file_priv->master); 295 mutex_unlock(&dev->master_mutex); 296 } 297 298 /** 299 * drm_is_current_master - checks whether @priv is the current master 300 * @fpriv: DRM file private 301 * 302 * Checks whether @fpriv is current master on its device. This decides whether a 303 * client is allowed to run DRM_MASTER IOCTLs. 304 * 305 * Most of the modern IOCTL which require DRM_MASTER are for kernel modesetting 306 * - the current master is assumed to own the non-shareable display hardware. 307 */ 308 bool drm_is_current_master(struct drm_file *fpriv) 309 { 310 return fpriv->is_master && drm_lease_owner(fpriv->master) == fpriv->minor->dev->master; 311 } 312 EXPORT_SYMBOL(drm_is_current_master); 313 314 /** 315 * drm_master_get - reference a master pointer 316 * @master: &struct drm_master 317 * 318 * Increments the reference count of @master and returns a pointer to @master. 319 */ 320 struct drm_master *drm_master_get(struct drm_master *master) 321 { 322 kref_get(&master->refcount); 323 return master; 324 } 325 EXPORT_SYMBOL(drm_master_get); 326 327 static void drm_master_destroy(struct kref *kref) 328 { 329 struct drm_master *master = container_of(kref, struct drm_master, refcount); 330 struct drm_device *dev = master->dev; 331 332 if (drm_core_check_feature(dev, DRIVER_MODESET)) 333 drm_lease_destroy(master); 334 335 if (dev->driver->master_destroy) 336 dev->driver->master_destroy(dev, master); 337 338 drm_legacy_master_rmmaps(dev, master); 339 340 idr_destroy(&master->magic_map); 341 idr_destroy(&master->leases); 342 idr_destroy(&master->lessee_idr); 343 344 kfree(master->unique); 345 kfree(master); 346 } 347 348 /** 349 * drm_master_put - unreference and clear a master pointer 350 * @master: pointer to a pointer of &struct drm_master 351 * 352 * This decrements the &drm_master behind @master and sets it to NULL. 353 */ 354 void drm_master_put(struct drm_master **master) 355 { 356 kref_put(&(*master)->refcount, drm_master_destroy); 357 *master = NULL; 358 } 359 EXPORT_SYMBOL(drm_master_put); 360 361 /* Used by drm_client and drm_fb_helper */ 362 bool drm_master_internal_acquire(struct drm_device *dev) 363 { 364 mutex_lock(&dev->master_mutex); 365 if (dev->master) { 366 mutex_unlock(&dev->master_mutex); 367 return false; 368 } 369 370 return true; 371 } 372 EXPORT_SYMBOL(drm_master_internal_acquire); 373 374 /* Used by drm_client and drm_fb_helper */ 375 void drm_master_internal_release(struct drm_device *dev) 376 { 377 mutex_unlock(&dev->master_mutex); 378 } 379 EXPORT_SYMBOL(drm_master_internal_release); 380