1 /* 2 * Copyright © 2008 Intel Corporation 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice (including the next 12 * paragraph) shall be included in all copies or substantial portions of the 13 * Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 21 * IN THE SOFTWARE. 22 * 23 * Authors: 24 * Eric Anholt <eric@anholt.net> 25 * 26 */ 27 28 #include <linux/types.h> 29 #include <linux/slab.h> 30 #include <linux/mm.h> 31 #include <linux/uaccess.h> 32 #include <linux/fs.h> 33 #include <linux/file.h> 34 #include <linux/module.h> 35 #include <linux/mman.h> 36 #include <linux/pagemap.h> 37 #include <linux/shmem_fs.h> 38 #include <linux/dma-buf.h> 39 #include <drm/drmP.h> 40 #include <drm/drm_vma_manager.h> 41 #include <drm/drm_gem.h> 42 #include "drm_internal.h" 43 44 /** @file drm_gem.c 45 * 46 * This file provides some of the base ioctls and library routines for 47 * the graphics memory manager implemented by each device driver. 48 * 49 * Because various devices have different requirements in terms of 50 * synchronization and migration strategies, implementing that is left up to 51 * the driver, and all that the general API provides should be generic -- 52 * allocating objects, reading/writing data with the cpu, freeing objects. 53 * Even there, platform-dependent optimizations for reading/writing data with 54 * the CPU mean we'll likely hook those out to driver-specific calls. However, 55 * the DRI2 implementation wants to have at least allocate/mmap be generic. 56 * 57 * The goal was to have swap-backed object allocation managed through 58 * struct file. However, file descriptors as handles to a struct file have 59 * two major failings: 60 * - Process limits prevent more than 1024 or so being used at a time by 61 * default. 62 * - Inability to allocate high fds will aggravate the X Server's select() 63 * handling, and likely that of many GL client applications as well. 64 * 65 * This led to a plan of using our own integer IDs (called handles, following 66 * DRM terminology) to mimic fds, and implement the fd syscalls we need as 67 * ioctls. The objects themselves will still include the struct file so 68 * that we can transition to fds if the required kernel infrastructure shows 69 * up at a later date, and as our interface with shmfs for memory allocation. 70 */ 71 72 /* 73 * We make up offsets for buffer objects so we can recognize them at 74 * mmap time. 75 */ 76 77 /* pgoff in mmap is an unsigned long, so we need to make sure that 78 * the faked up offset will fit 79 */ 80 81 #if BITS_PER_LONG == 64 82 #define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFFUL >> PAGE_SHIFT) + 1) 83 #define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFFUL >> PAGE_SHIFT) * 16) 84 #else 85 #define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFUL >> PAGE_SHIFT) + 1) 86 #define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFUL >> PAGE_SHIFT) * 16) 87 #endif 88 89 /** 90 * drm_gem_init - Initialize the GEM device fields 91 * @dev: drm_devic structure to initialize 92 */ 93 int 94 drm_gem_init(struct drm_device *dev) 95 { 96 struct drm_vma_offset_manager *vma_offset_manager; 97 98 mutex_init(&dev->object_name_lock); 99 idr_init(&dev->object_name_idr); 100 101 vma_offset_manager = kzalloc(sizeof(*vma_offset_manager), GFP_KERNEL); 102 if (!vma_offset_manager) { 103 DRM_ERROR("out of memory\n"); 104 return -ENOMEM; 105 } 106 107 dev->vma_offset_manager = vma_offset_manager; 108 drm_vma_offset_manager_init(vma_offset_manager, 109 DRM_FILE_PAGE_OFFSET_START, 110 DRM_FILE_PAGE_OFFSET_SIZE); 111 112 return 0; 113 } 114 115 void 116 drm_gem_destroy(struct drm_device *dev) 117 { 118 119 drm_vma_offset_manager_destroy(dev->vma_offset_manager); 120 kfree(dev->vma_offset_manager); 121 dev->vma_offset_manager = NULL; 122 } 123 124 /** 125 * drm_gem_object_init - initialize an allocated shmem-backed GEM object 126 * @dev: drm_device the object should be initialized for 127 * @obj: drm_gem_object to initialize 128 * @size: object size 129 * 130 * Initialize an already allocated GEM object of the specified size with 131 * shmfs backing store. 132 */ 133 int drm_gem_object_init(struct drm_device *dev, 134 struct drm_gem_object *obj, size_t size) 135 { 136 struct file *filp; 137 138 drm_gem_private_object_init(dev, obj, size); 139 140 filp = shmem_file_setup("drm mm object", size, VM_NORESERVE); 141 if (IS_ERR(filp)) 142 return PTR_ERR(filp); 143 144 obj->filp = filp; 145 146 return 0; 147 } 148 EXPORT_SYMBOL(drm_gem_object_init); 149 150 /** 151 * drm_gem_private_object_init - initialize an allocated private GEM object 152 * @dev: drm_device the object should be initialized for 153 * @obj: drm_gem_object to initialize 154 * @size: object size 155 * 156 * Initialize an already allocated GEM object of the specified size with 157 * no GEM provided backing store. Instead the caller is responsible for 158 * backing the object and handling it. 159 */ 160 void drm_gem_private_object_init(struct drm_device *dev, 161 struct drm_gem_object *obj, size_t size) 162 { 163 BUG_ON((size & (PAGE_SIZE - 1)) != 0); 164 165 obj->dev = dev; 166 obj->filp = NULL; 167 168 kref_init(&obj->refcount); 169 obj->handle_count = 0; 170 obj->size = size; 171 drm_vma_node_reset(&obj->vma_node); 172 } 173 EXPORT_SYMBOL(drm_gem_private_object_init); 174 175 static void 176 drm_gem_remove_prime_handles(struct drm_gem_object *obj, struct drm_file *filp) 177 { 178 /* 179 * Note: obj->dma_buf can't disappear as long as we still hold a 180 * handle reference in obj->handle_count. 181 */ 182 mutex_lock(&filp->prime.lock); 183 if (obj->dma_buf) { 184 drm_prime_remove_buf_handle_locked(&filp->prime, 185 obj->dma_buf); 186 } 187 mutex_unlock(&filp->prime.lock); 188 } 189 190 /** 191 * drm_gem_object_handle_free - release resources bound to userspace handles 192 * @obj: GEM object to clean up. 193 * 194 * Called after the last handle to the object has been closed 195 * 196 * Removes any name for the object. Note that this must be 197 * called before drm_gem_object_free or we'll be touching 198 * freed memory 199 */ 200 static void drm_gem_object_handle_free(struct drm_gem_object *obj) 201 { 202 struct drm_device *dev = obj->dev; 203 204 /* Remove any name for this object */ 205 if (obj->name) { 206 idr_remove(&dev->object_name_idr, obj->name); 207 obj->name = 0; 208 } 209 } 210 211 static void drm_gem_object_exported_dma_buf_free(struct drm_gem_object *obj) 212 { 213 /* Unbreak the reference cycle if we have an exported dma_buf. */ 214 if (obj->dma_buf) { 215 dma_buf_put(obj->dma_buf); 216 obj->dma_buf = NULL; 217 } 218 } 219 220 static void 221 drm_gem_object_handle_unreference_unlocked(struct drm_gem_object *obj) 222 { 223 if (WARN_ON(obj->handle_count == 0)) 224 return; 225 226 /* 227 * Must bump handle count first as this may be the last 228 * ref, in which case the object would disappear before we 229 * checked for a name 230 */ 231 232 mutex_lock(&obj->dev->object_name_lock); 233 if (--obj->handle_count == 0) { 234 drm_gem_object_handle_free(obj); 235 drm_gem_object_exported_dma_buf_free(obj); 236 } 237 mutex_unlock(&obj->dev->object_name_lock); 238 239 drm_gem_object_unreference_unlocked(obj); 240 } 241 242 /** 243 * drm_gem_handle_delete - deletes the given file-private handle 244 * @filp: drm file-private structure to use for the handle look up 245 * @handle: userspace handle to delete 246 * 247 * Removes the GEM handle from the @filp lookup table and if this is the last 248 * handle also cleans up linked resources like GEM names. 249 */ 250 int 251 drm_gem_handle_delete(struct drm_file *filp, u32 handle) 252 { 253 struct drm_device *dev; 254 struct drm_gem_object *obj; 255 256 /* This is gross. The idr system doesn't let us try a delete and 257 * return an error code. It just spews if you fail at deleting. 258 * So, we have to grab a lock around finding the object and then 259 * doing the delete on it and dropping the refcount, or the user 260 * could race us to double-decrement the refcount and cause a 261 * use-after-free later. Given the frequency of our handle lookups, 262 * we may want to use ida for number allocation and a hash table 263 * for the pointers, anyway. 264 */ 265 spin_lock(&filp->table_lock); 266 267 /* Check if we currently have a reference on the object */ 268 obj = idr_find(&filp->object_idr, handle); 269 if (obj == NULL) { 270 spin_unlock(&filp->table_lock); 271 return -EINVAL; 272 } 273 dev = obj->dev; 274 275 /* Release reference and decrement refcount. */ 276 idr_remove(&filp->object_idr, handle); 277 spin_unlock(&filp->table_lock); 278 279 if (drm_core_check_feature(dev, DRIVER_PRIME)) 280 drm_gem_remove_prime_handles(obj, filp); 281 drm_vma_node_revoke(&obj->vma_node, filp->filp); 282 283 if (dev->driver->gem_close_object) 284 dev->driver->gem_close_object(obj, filp); 285 drm_gem_object_handle_unreference_unlocked(obj); 286 287 return 0; 288 } 289 EXPORT_SYMBOL(drm_gem_handle_delete); 290 291 /** 292 * drm_gem_dumb_destroy - dumb fb callback helper for gem based drivers 293 * @file: drm file-private structure to remove the dumb handle from 294 * @dev: corresponding drm_device 295 * @handle: the dumb handle to remove 296 * 297 * This implements the ->dumb_destroy kms driver callback for drivers which use 298 * gem to manage their backing storage. 299 */ 300 int drm_gem_dumb_destroy(struct drm_file *file, 301 struct drm_device *dev, 302 uint32_t handle) 303 { 304 return drm_gem_handle_delete(file, handle); 305 } 306 EXPORT_SYMBOL(drm_gem_dumb_destroy); 307 308 /** 309 * drm_gem_handle_create_tail - internal functions to create a handle 310 * @file_priv: drm file-private structure to register the handle for 311 * @obj: object to register 312 * @handlep: pointer to return the created handle to the caller 313 * 314 * This expects the dev->object_name_lock to be held already and will drop it 315 * before returning. Used to avoid races in establishing new handles when 316 * importing an object from either an flink name or a dma-buf. 317 */ 318 int 319 drm_gem_handle_create_tail(struct drm_file *file_priv, 320 struct drm_gem_object *obj, 321 u32 *handlep) 322 { 323 struct drm_device *dev = obj->dev; 324 int ret; 325 326 WARN_ON(!mutex_is_locked(&dev->object_name_lock)); 327 328 /* 329 * Get the user-visible handle using idr. Preload and perform 330 * allocation under our spinlock. 331 */ 332 idr_preload(GFP_KERNEL); 333 spin_lock(&file_priv->table_lock); 334 335 ret = idr_alloc(&file_priv->object_idr, obj, 1, 0, GFP_NOWAIT); 336 drm_gem_object_reference(obj); 337 obj->handle_count++; 338 spin_unlock(&file_priv->table_lock); 339 idr_preload_end(); 340 mutex_unlock(&dev->object_name_lock); 341 if (ret < 0) { 342 drm_gem_object_handle_unreference_unlocked(obj); 343 return ret; 344 } 345 *handlep = ret; 346 347 ret = drm_vma_node_allow(&obj->vma_node, file_priv->filp); 348 if (ret) { 349 drm_gem_handle_delete(file_priv, *handlep); 350 return ret; 351 } 352 353 if (dev->driver->gem_open_object) { 354 ret = dev->driver->gem_open_object(obj, file_priv); 355 if (ret) { 356 drm_gem_handle_delete(file_priv, *handlep); 357 return ret; 358 } 359 } 360 361 return 0; 362 } 363 364 /** 365 * drm_gem_handle_create - create a gem handle for an object 366 * @file_priv: drm file-private structure to register the handle for 367 * @obj: object to register 368 * @handlep: pionter to return the created handle to the caller 369 * 370 * Create a handle for this object. This adds a handle reference 371 * to the object, which includes a regular reference count. Callers 372 * will likely want to dereference the object afterwards. 373 */ 374 int drm_gem_handle_create(struct drm_file *file_priv, 375 struct drm_gem_object *obj, 376 u32 *handlep) 377 { 378 mutex_lock(&obj->dev->object_name_lock); 379 380 return drm_gem_handle_create_tail(file_priv, obj, handlep); 381 } 382 EXPORT_SYMBOL(drm_gem_handle_create); 383 384 385 /** 386 * drm_gem_free_mmap_offset - release a fake mmap offset for an object 387 * @obj: obj in question 388 * 389 * This routine frees fake offsets allocated by drm_gem_create_mmap_offset(). 390 */ 391 void 392 drm_gem_free_mmap_offset(struct drm_gem_object *obj) 393 { 394 struct drm_device *dev = obj->dev; 395 396 drm_vma_offset_remove(dev->vma_offset_manager, &obj->vma_node); 397 } 398 EXPORT_SYMBOL(drm_gem_free_mmap_offset); 399 400 /** 401 * drm_gem_create_mmap_offset_size - create a fake mmap offset for an object 402 * @obj: obj in question 403 * @size: the virtual size 404 * 405 * GEM memory mapping works by handing back to userspace a fake mmap offset 406 * it can use in a subsequent mmap(2) call. The DRM core code then looks 407 * up the object based on the offset and sets up the various memory mapping 408 * structures. 409 * 410 * This routine allocates and attaches a fake offset for @obj, in cases where 411 * the virtual size differs from the physical size (ie. obj->size). Otherwise 412 * just use drm_gem_create_mmap_offset(). 413 */ 414 int 415 drm_gem_create_mmap_offset_size(struct drm_gem_object *obj, size_t size) 416 { 417 struct drm_device *dev = obj->dev; 418 419 return drm_vma_offset_add(dev->vma_offset_manager, &obj->vma_node, 420 size / PAGE_SIZE); 421 } 422 EXPORT_SYMBOL(drm_gem_create_mmap_offset_size); 423 424 /** 425 * drm_gem_create_mmap_offset - create a fake mmap offset for an object 426 * @obj: obj in question 427 * 428 * GEM memory mapping works by handing back to userspace a fake mmap offset 429 * it can use in a subsequent mmap(2) call. The DRM core code then looks 430 * up the object based on the offset and sets up the various memory mapping 431 * structures. 432 * 433 * This routine allocates and attaches a fake offset for @obj. 434 */ 435 int drm_gem_create_mmap_offset(struct drm_gem_object *obj) 436 { 437 return drm_gem_create_mmap_offset_size(obj, obj->size); 438 } 439 EXPORT_SYMBOL(drm_gem_create_mmap_offset); 440 441 /** 442 * drm_gem_get_pages - helper to allocate backing pages for a GEM object 443 * from shmem 444 * @obj: obj in question 445 * 446 * This reads the page-array of the shmem-backing storage of the given gem 447 * object. An array of pages is returned. If a page is not allocated or 448 * swapped-out, this will allocate/swap-in the required pages. Note that the 449 * whole object is covered by the page-array and pinned in memory. 450 * 451 * Use drm_gem_put_pages() to release the array and unpin all pages. 452 * 453 * This uses the GFP-mask set on the shmem-mapping (see mapping_set_gfp_mask()). 454 * If you require other GFP-masks, you have to do those allocations yourself. 455 * 456 * Note that you are not allowed to change gfp-zones during runtime. That is, 457 * shmem_read_mapping_page_gfp() must be called with the same gfp_zone(gfp) as 458 * set during initialization. If you have special zone constraints, set them 459 * after drm_gem_init_object() via mapping_set_gfp_mask(). shmem-core takes care 460 * to keep pages in the required zone during swap-in. 461 */ 462 struct page **drm_gem_get_pages(struct drm_gem_object *obj) 463 { 464 struct address_space *mapping; 465 struct page *p, **pages; 466 int i, npages; 467 468 /* This is the shared memory object that backs the GEM resource */ 469 mapping = file_inode(obj->filp)->i_mapping; 470 471 /* We already BUG_ON() for non-page-aligned sizes in 472 * drm_gem_object_init(), so we should never hit this unless 473 * driver author is doing something really wrong: 474 */ 475 WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0); 476 477 npages = obj->size >> PAGE_SHIFT; 478 479 pages = drm_malloc_ab(npages, sizeof(struct page *)); 480 if (pages == NULL) 481 return ERR_PTR(-ENOMEM); 482 483 for (i = 0; i < npages; i++) { 484 p = shmem_read_mapping_page(mapping, i); 485 if (IS_ERR(p)) 486 goto fail; 487 pages[i] = p; 488 489 /* Make sure shmem keeps __GFP_DMA32 allocated pages in the 490 * correct region during swapin. Note that this requires 491 * __GFP_DMA32 to be set in mapping_gfp_mask(inode->i_mapping) 492 * so shmem can relocate pages during swapin if required. 493 */ 494 BUG_ON(mapping_gfp_constraint(mapping, __GFP_DMA32) && 495 (page_to_pfn(p) >= 0x00100000UL)); 496 } 497 498 return pages; 499 500 fail: 501 while (i--) 502 page_cache_release(pages[i]); 503 504 drm_free_large(pages); 505 return ERR_CAST(p); 506 } 507 EXPORT_SYMBOL(drm_gem_get_pages); 508 509 /** 510 * drm_gem_put_pages - helper to free backing pages for a GEM object 511 * @obj: obj in question 512 * @pages: pages to free 513 * @dirty: if true, pages will be marked as dirty 514 * @accessed: if true, the pages will be marked as accessed 515 */ 516 void drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages, 517 bool dirty, bool accessed) 518 { 519 int i, npages; 520 521 /* We already BUG_ON() for non-page-aligned sizes in 522 * drm_gem_object_init(), so we should never hit this unless 523 * driver author is doing something really wrong: 524 */ 525 WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0); 526 527 npages = obj->size >> PAGE_SHIFT; 528 529 for (i = 0; i < npages; i++) { 530 if (dirty) 531 set_page_dirty(pages[i]); 532 533 if (accessed) 534 mark_page_accessed(pages[i]); 535 536 /* Undo the reference we took when populating the table */ 537 page_cache_release(pages[i]); 538 } 539 540 drm_free_large(pages); 541 } 542 EXPORT_SYMBOL(drm_gem_put_pages); 543 544 /** Returns a reference to the object named by the handle. */ 545 struct drm_gem_object * 546 drm_gem_object_lookup(struct drm_device *dev, struct drm_file *filp, 547 u32 handle) 548 { 549 struct drm_gem_object *obj; 550 551 spin_lock(&filp->table_lock); 552 553 /* Check if we currently have a reference on the object */ 554 obj = idr_find(&filp->object_idr, handle); 555 if (obj == NULL) { 556 spin_unlock(&filp->table_lock); 557 return NULL; 558 } 559 560 drm_gem_object_reference(obj); 561 562 spin_unlock(&filp->table_lock); 563 564 return obj; 565 } 566 EXPORT_SYMBOL(drm_gem_object_lookup); 567 568 /** 569 * drm_gem_close_ioctl - implementation of the GEM_CLOSE ioctl 570 * @dev: drm_device 571 * @data: ioctl data 572 * @file_priv: drm file-private structure 573 * 574 * Releases the handle to an mm object. 575 */ 576 int 577 drm_gem_close_ioctl(struct drm_device *dev, void *data, 578 struct drm_file *file_priv) 579 { 580 struct drm_gem_close *args = data; 581 int ret; 582 583 if (!drm_core_check_feature(dev, DRIVER_GEM)) 584 return -ENODEV; 585 586 ret = drm_gem_handle_delete(file_priv, args->handle); 587 588 return ret; 589 } 590 591 /** 592 * drm_gem_flink_ioctl - implementation of the GEM_FLINK ioctl 593 * @dev: drm_device 594 * @data: ioctl data 595 * @file_priv: drm file-private structure 596 * 597 * Create a global name for an object, returning the name. 598 * 599 * Note that the name does not hold a reference; when the object 600 * is freed, the name goes away. 601 */ 602 int 603 drm_gem_flink_ioctl(struct drm_device *dev, void *data, 604 struct drm_file *file_priv) 605 { 606 struct drm_gem_flink *args = data; 607 struct drm_gem_object *obj; 608 int ret; 609 610 if (!drm_core_check_feature(dev, DRIVER_GEM)) 611 return -ENODEV; 612 613 obj = drm_gem_object_lookup(dev, file_priv, args->handle); 614 if (obj == NULL) 615 return -ENOENT; 616 617 mutex_lock(&dev->object_name_lock); 618 idr_preload(GFP_KERNEL); 619 /* prevent races with concurrent gem_close. */ 620 if (obj->handle_count == 0) { 621 ret = -ENOENT; 622 goto err; 623 } 624 625 if (!obj->name) { 626 ret = idr_alloc(&dev->object_name_idr, obj, 1, 0, GFP_NOWAIT); 627 if (ret < 0) 628 goto err; 629 630 obj->name = ret; 631 } 632 633 args->name = (uint64_t) obj->name; 634 ret = 0; 635 636 err: 637 idr_preload_end(); 638 mutex_unlock(&dev->object_name_lock); 639 drm_gem_object_unreference_unlocked(obj); 640 return ret; 641 } 642 643 /** 644 * drm_gem_open - implementation of the GEM_OPEN ioctl 645 * @dev: drm_device 646 * @data: ioctl data 647 * @file_priv: drm file-private structure 648 * 649 * Open an object using the global name, returning a handle and the size. 650 * 651 * This handle (of course) holds a reference to the object, so the object 652 * will not go away until the handle is deleted. 653 */ 654 int 655 drm_gem_open_ioctl(struct drm_device *dev, void *data, 656 struct drm_file *file_priv) 657 { 658 struct drm_gem_open *args = data; 659 struct drm_gem_object *obj; 660 int ret; 661 u32 handle; 662 663 if (!drm_core_check_feature(dev, DRIVER_GEM)) 664 return -ENODEV; 665 666 mutex_lock(&dev->object_name_lock); 667 obj = idr_find(&dev->object_name_idr, (int) args->name); 668 if (obj) { 669 drm_gem_object_reference(obj); 670 } else { 671 mutex_unlock(&dev->object_name_lock); 672 return -ENOENT; 673 } 674 675 /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */ 676 ret = drm_gem_handle_create_tail(file_priv, obj, &handle); 677 drm_gem_object_unreference_unlocked(obj); 678 if (ret) 679 return ret; 680 681 args->handle = handle; 682 args->size = obj->size; 683 684 return 0; 685 } 686 687 /** 688 * gem_gem_open - initalizes GEM file-private structures at devnode open time 689 * @dev: drm_device which is being opened by userspace 690 * @file_private: drm file-private structure to set up 691 * 692 * Called at device open time, sets up the structure for handling refcounting 693 * of mm objects. 694 */ 695 void 696 drm_gem_open(struct drm_device *dev, struct drm_file *file_private) 697 { 698 idr_init(&file_private->object_idr); 699 spin_lock_init(&file_private->table_lock); 700 } 701 702 /* 703 * Called at device close to release the file's 704 * handle references on objects. 705 */ 706 static int 707 drm_gem_object_release_handle(int id, void *ptr, void *data) 708 { 709 struct drm_file *file_priv = data; 710 struct drm_gem_object *obj = ptr; 711 struct drm_device *dev = obj->dev; 712 713 if (drm_core_check_feature(dev, DRIVER_PRIME)) 714 drm_gem_remove_prime_handles(obj, file_priv); 715 drm_vma_node_revoke(&obj->vma_node, file_priv->filp); 716 717 if (dev->driver->gem_close_object) 718 dev->driver->gem_close_object(obj, file_priv); 719 720 drm_gem_object_handle_unreference_unlocked(obj); 721 722 return 0; 723 } 724 725 /** 726 * drm_gem_release - release file-private GEM resources 727 * @dev: drm_device which is being closed by userspace 728 * @file_private: drm file-private structure to clean up 729 * 730 * Called at close time when the filp is going away. 731 * 732 * Releases any remaining references on objects by this filp. 733 */ 734 void 735 drm_gem_release(struct drm_device *dev, struct drm_file *file_private) 736 { 737 idr_for_each(&file_private->object_idr, 738 &drm_gem_object_release_handle, file_private); 739 idr_destroy(&file_private->object_idr); 740 } 741 742 void 743 drm_gem_object_release(struct drm_gem_object *obj) 744 { 745 WARN_ON(obj->dma_buf); 746 747 if (obj->filp) 748 fput(obj->filp); 749 750 drm_gem_free_mmap_offset(obj); 751 } 752 EXPORT_SYMBOL(drm_gem_object_release); 753 754 /** 755 * drm_gem_object_free - free a GEM object 756 * @kref: kref of the object to free 757 * 758 * Called after the last reference to the object has been lost. 759 * Must be called holding struct_ mutex 760 * 761 * Frees the object 762 */ 763 void 764 drm_gem_object_free(struct kref *kref) 765 { 766 struct drm_gem_object *obj = 767 container_of(kref, struct drm_gem_object, refcount); 768 struct drm_device *dev = obj->dev; 769 770 WARN_ON(!mutex_is_locked(&dev->struct_mutex)); 771 772 if (dev->driver->gem_free_object != NULL) 773 dev->driver->gem_free_object(obj); 774 } 775 EXPORT_SYMBOL(drm_gem_object_free); 776 777 void drm_gem_vm_open(struct vm_area_struct *vma) 778 { 779 struct drm_gem_object *obj = vma->vm_private_data; 780 781 drm_gem_object_reference(obj); 782 } 783 EXPORT_SYMBOL(drm_gem_vm_open); 784 785 void drm_gem_vm_close(struct vm_area_struct *vma) 786 { 787 struct drm_gem_object *obj = vma->vm_private_data; 788 789 drm_gem_object_unreference_unlocked(obj); 790 } 791 EXPORT_SYMBOL(drm_gem_vm_close); 792 793 /** 794 * drm_gem_mmap_obj - memory map a GEM object 795 * @obj: the GEM object to map 796 * @obj_size: the object size to be mapped, in bytes 797 * @vma: VMA for the area to be mapped 798 * 799 * Set up the VMA to prepare mapping of the GEM object using the gem_vm_ops 800 * provided by the driver. Depending on their requirements, drivers can either 801 * provide a fault handler in their gem_vm_ops (in which case any accesses to 802 * the object will be trapped, to perform migration, GTT binding, surface 803 * register allocation, or performance monitoring), or mmap the buffer memory 804 * synchronously after calling drm_gem_mmap_obj. 805 * 806 * This function is mainly intended to implement the DMABUF mmap operation, when 807 * the GEM object is not looked up based on its fake offset. To implement the 808 * DRM mmap operation, drivers should use the drm_gem_mmap() function. 809 * 810 * drm_gem_mmap_obj() assumes the user is granted access to the buffer while 811 * drm_gem_mmap() prevents unprivileged users from mapping random objects. So 812 * callers must verify access restrictions before calling this helper. 813 * 814 * Return 0 or success or -EINVAL if the object size is smaller than the VMA 815 * size, or if no gem_vm_ops are provided. 816 */ 817 int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size, 818 struct vm_area_struct *vma) 819 { 820 struct drm_device *dev = obj->dev; 821 822 /* Check for valid size. */ 823 if (obj_size < vma->vm_end - vma->vm_start) 824 return -EINVAL; 825 826 if (!dev->driver->gem_vm_ops) 827 return -EINVAL; 828 829 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; 830 vma->vm_ops = dev->driver->gem_vm_ops; 831 vma->vm_private_data = obj; 832 vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags)); 833 834 /* Take a ref for this mapping of the object, so that the fault 835 * handler can dereference the mmap offset's pointer to the object. 836 * This reference is cleaned up by the corresponding vm_close 837 * (which should happen whether the vma was created by this call, or 838 * by a vm_open due to mremap or partial unmap or whatever). 839 */ 840 drm_gem_object_reference(obj); 841 842 return 0; 843 } 844 EXPORT_SYMBOL(drm_gem_mmap_obj); 845 846 /** 847 * drm_gem_mmap - memory map routine for GEM objects 848 * @filp: DRM file pointer 849 * @vma: VMA for the area to be mapped 850 * 851 * If a driver supports GEM object mapping, mmap calls on the DRM file 852 * descriptor will end up here. 853 * 854 * Look up the GEM object based on the offset passed in (vma->vm_pgoff will 855 * contain the fake offset we created when the GTT map ioctl was called on 856 * the object) and map it with a call to drm_gem_mmap_obj(). 857 * 858 * If the caller is not granted access to the buffer object, the mmap will fail 859 * with EACCES. Please see the vma manager for more information. 860 */ 861 int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma) 862 { 863 struct drm_file *priv = filp->private_data; 864 struct drm_device *dev = priv->minor->dev; 865 struct drm_gem_object *obj = NULL; 866 struct drm_vma_offset_node *node; 867 int ret; 868 869 if (drm_device_is_unplugged(dev)) 870 return -ENODEV; 871 872 drm_vma_offset_lock_lookup(dev->vma_offset_manager); 873 node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager, 874 vma->vm_pgoff, 875 vma_pages(vma)); 876 if (likely(node)) { 877 obj = container_of(node, struct drm_gem_object, vma_node); 878 /* 879 * When the object is being freed, after it hits 0-refcnt it 880 * proceeds to tear down the object. In the process it will 881 * attempt to remove the VMA offset and so acquire this 882 * mgr->vm_lock. Therefore if we find an object with a 0-refcnt 883 * that matches our range, we know it is in the process of being 884 * destroyed and will be freed as soon as we release the lock - 885 * so we have to check for the 0-refcnted object and treat it as 886 * invalid. 887 */ 888 if (!kref_get_unless_zero(&obj->refcount)) 889 obj = NULL; 890 } 891 drm_vma_offset_unlock_lookup(dev->vma_offset_manager); 892 893 if (!obj) 894 return -EINVAL; 895 896 if (!drm_vma_node_is_allowed(node, filp)) { 897 drm_gem_object_unreference_unlocked(obj); 898 return -EACCES; 899 } 900 901 ret = drm_gem_mmap_obj(obj, drm_vma_node_size(node) << PAGE_SHIFT, 902 vma); 903 904 drm_gem_object_unreference_unlocked(obj); 905 906 return ret; 907 } 908 EXPORT_SYMBOL(drm_gem_mmap); 909