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 struct drm_device *dev = obj->dev; 224 bool final = false; 225 226 if (WARN_ON(obj->handle_count == 0)) 227 return; 228 229 /* 230 * Must bump handle count first as this may be the last 231 * ref, in which case the object would disappear before we 232 * checked for a name 233 */ 234 235 mutex_lock(&dev->object_name_lock); 236 if (--obj->handle_count == 0) { 237 drm_gem_object_handle_free(obj); 238 drm_gem_object_exported_dma_buf_free(obj); 239 final = true; 240 } 241 mutex_unlock(&dev->object_name_lock); 242 243 if (final) 244 drm_gem_object_unreference_unlocked(obj); 245 } 246 247 /* 248 * Called at device or object close to release the file's 249 * handle references on objects. 250 */ 251 static int 252 drm_gem_object_release_handle(int id, void *ptr, void *data) 253 { 254 struct drm_file *file_priv = data; 255 struct drm_gem_object *obj = ptr; 256 struct drm_device *dev = obj->dev; 257 258 if (drm_core_check_feature(dev, DRIVER_PRIME)) 259 drm_gem_remove_prime_handles(obj, file_priv); 260 drm_vma_node_revoke(&obj->vma_node, file_priv->filp); 261 262 if (dev->driver->gem_close_object) 263 dev->driver->gem_close_object(obj, file_priv); 264 265 drm_gem_object_handle_unreference_unlocked(obj); 266 267 return 0; 268 } 269 270 /** 271 * drm_gem_handle_delete - deletes the given file-private handle 272 * @filp: drm file-private structure to use for the handle look up 273 * @handle: userspace handle to delete 274 * 275 * Removes the GEM handle from the @filp lookup table which has been added with 276 * drm_gem_handle_create(). If this is the last handle also cleans up linked 277 * resources like GEM names. 278 */ 279 int 280 drm_gem_handle_delete(struct drm_file *filp, u32 handle) 281 { 282 struct drm_gem_object *obj; 283 284 /* This is gross. The idr system doesn't let us try a delete and 285 * return an error code. It just spews if you fail at deleting. 286 * So, we have to grab a lock around finding the object and then 287 * doing the delete on it and dropping the refcount, or the user 288 * could race us to double-decrement the refcount and cause a 289 * use-after-free later. Given the frequency of our handle lookups, 290 * we may want to use ida for number allocation and a hash table 291 * for the pointers, anyway. 292 */ 293 spin_lock(&filp->table_lock); 294 295 /* Check if we currently have a reference on the object */ 296 obj = idr_replace(&filp->object_idr, NULL, handle); 297 spin_unlock(&filp->table_lock); 298 if (IS_ERR_OR_NULL(obj)) 299 return -EINVAL; 300 301 /* Release driver's reference and decrement refcount. */ 302 drm_gem_object_release_handle(handle, obj, filp); 303 304 /* And finally make the handle available for future allocations. */ 305 spin_lock(&filp->table_lock); 306 idr_remove(&filp->object_idr, handle); 307 spin_unlock(&filp->table_lock); 308 309 return 0; 310 } 311 EXPORT_SYMBOL(drm_gem_handle_delete); 312 313 /** 314 * drm_gem_dumb_destroy - dumb fb callback helper for gem based drivers 315 * @file: drm file-private structure to remove the dumb handle from 316 * @dev: corresponding drm_device 317 * @handle: the dumb handle to remove 318 * 319 * This implements the ->dumb_destroy kms driver callback for drivers which use 320 * gem to manage their backing storage. 321 */ 322 int drm_gem_dumb_destroy(struct drm_file *file, 323 struct drm_device *dev, 324 uint32_t handle) 325 { 326 return drm_gem_handle_delete(file, handle); 327 } 328 EXPORT_SYMBOL(drm_gem_dumb_destroy); 329 330 /** 331 * drm_gem_handle_create_tail - internal functions to create a handle 332 * @file_priv: drm file-private structure to register the handle for 333 * @obj: object to register 334 * @handlep: pointer to return the created handle to the caller 335 * 336 * This expects the dev->object_name_lock to be held already and will drop it 337 * before returning. Used to avoid races in establishing new handles when 338 * importing an object from either an flink name or a dma-buf. 339 * 340 * Handles must be release again through drm_gem_handle_delete(). This is done 341 * when userspace closes @file_priv for all attached handles, or through the 342 * GEM_CLOSE ioctl for individual handles. 343 */ 344 int 345 drm_gem_handle_create_tail(struct drm_file *file_priv, 346 struct drm_gem_object *obj, 347 u32 *handlep) 348 { 349 struct drm_device *dev = obj->dev; 350 u32 handle; 351 int ret; 352 353 WARN_ON(!mutex_is_locked(&dev->object_name_lock)); 354 if (obj->handle_count++ == 0) 355 drm_gem_object_reference(obj); 356 357 /* 358 * Get the user-visible handle using idr. Preload and perform 359 * allocation under our spinlock. 360 */ 361 idr_preload(GFP_KERNEL); 362 spin_lock(&file_priv->table_lock); 363 364 ret = idr_alloc(&file_priv->object_idr, obj, 1, 0, GFP_NOWAIT); 365 366 spin_unlock(&file_priv->table_lock); 367 idr_preload_end(); 368 369 mutex_unlock(&dev->object_name_lock); 370 if (ret < 0) 371 goto err_unref; 372 373 handle = ret; 374 375 ret = drm_vma_node_allow(&obj->vma_node, file_priv->filp); 376 if (ret) 377 goto err_remove; 378 379 if (dev->driver->gem_open_object) { 380 ret = dev->driver->gem_open_object(obj, file_priv); 381 if (ret) 382 goto err_revoke; 383 } 384 385 *handlep = handle; 386 return 0; 387 388 err_revoke: 389 drm_vma_node_revoke(&obj->vma_node, file_priv->filp); 390 err_remove: 391 spin_lock(&file_priv->table_lock); 392 idr_remove(&file_priv->object_idr, handle); 393 spin_unlock(&file_priv->table_lock); 394 err_unref: 395 drm_gem_object_handle_unreference_unlocked(obj); 396 return ret; 397 } 398 399 /** 400 * drm_gem_handle_create - create a gem handle for an object 401 * @file_priv: drm file-private structure to register the handle for 402 * @obj: object to register 403 * @handlep: pionter to return the created handle to the caller 404 * 405 * Create a handle for this object. This adds a handle reference 406 * to the object, which includes a regular reference count. Callers 407 * will likely want to dereference the object afterwards. 408 */ 409 int drm_gem_handle_create(struct drm_file *file_priv, 410 struct drm_gem_object *obj, 411 u32 *handlep) 412 { 413 mutex_lock(&obj->dev->object_name_lock); 414 415 return drm_gem_handle_create_tail(file_priv, obj, handlep); 416 } 417 EXPORT_SYMBOL(drm_gem_handle_create); 418 419 420 /** 421 * drm_gem_free_mmap_offset - release a fake mmap offset for an object 422 * @obj: obj in question 423 * 424 * This routine frees fake offsets allocated by drm_gem_create_mmap_offset(). 425 * 426 * Note that drm_gem_object_release() already calls this function, so drivers 427 * don't have to take care of releasing the mmap offset themselves when freeing 428 * the GEM object. 429 */ 430 void 431 drm_gem_free_mmap_offset(struct drm_gem_object *obj) 432 { 433 struct drm_device *dev = obj->dev; 434 435 drm_vma_offset_remove(dev->vma_offset_manager, &obj->vma_node); 436 } 437 EXPORT_SYMBOL(drm_gem_free_mmap_offset); 438 439 /** 440 * drm_gem_create_mmap_offset_size - create a fake mmap offset for an object 441 * @obj: obj in question 442 * @size: the virtual size 443 * 444 * GEM memory mapping works by handing back to userspace a fake mmap offset 445 * it can use in a subsequent mmap(2) call. The DRM core code then looks 446 * up the object based on the offset and sets up the various memory mapping 447 * structures. 448 * 449 * This routine allocates and attaches a fake offset for @obj, in cases where 450 * the virtual size differs from the physical size (ie. obj->size). Otherwise 451 * just use drm_gem_create_mmap_offset(). 452 * 453 * This function is idempotent and handles an already allocated mmap offset 454 * transparently. Drivers do not need to check for this case. 455 */ 456 int 457 drm_gem_create_mmap_offset_size(struct drm_gem_object *obj, size_t size) 458 { 459 struct drm_device *dev = obj->dev; 460 461 return drm_vma_offset_add(dev->vma_offset_manager, &obj->vma_node, 462 size / PAGE_SIZE); 463 } 464 EXPORT_SYMBOL(drm_gem_create_mmap_offset_size); 465 466 /** 467 * drm_gem_create_mmap_offset - create a fake mmap offset for an object 468 * @obj: obj in question 469 * 470 * GEM memory mapping works by handing back to userspace a fake mmap offset 471 * it can use in a subsequent mmap(2) call. The DRM core code then looks 472 * up the object based on the offset and sets up the various memory mapping 473 * structures. 474 * 475 * This routine allocates and attaches a fake offset for @obj. 476 * 477 * Drivers can call drm_gem_free_mmap_offset() before freeing @obj to release 478 * the fake offset again. 479 */ 480 int drm_gem_create_mmap_offset(struct drm_gem_object *obj) 481 { 482 return drm_gem_create_mmap_offset_size(obj, obj->size); 483 } 484 EXPORT_SYMBOL(drm_gem_create_mmap_offset); 485 486 /** 487 * drm_gem_get_pages - helper to allocate backing pages for a GEM object 488 * from shmem 489 * @obj: obj in question 490 * 491 * This reads the page-array of the shmem-backing storage of the given gem 492 * object. An array of pages is returned. If a page is not allocated or 493 * swapped-out, this will allocate/swap-in the required pages. Note that the 494 * whole object is covered by the page-array and pinned in memory. 495 * 496 * Use drm_gem_put_pages() to release the array and unpin all pages. 497 * 498 * This uses the GFP-mask set on the shmem-mapping (see mapping_set_gfp_mask()). 499 * If you require other GFP-masks, you have to do those allocations yourself. 500 * 501 * Note that you are not allowed to change gfp-zones during runtime. That is, 502 * shmem_read_mapping_page_gfp() must be called with the same gfp_zone(gfp) as 503 * set during initialization. If you have special zone constraints, set them 504 * after drm_gem_init_object() via mapping_set_gfp_mask(). shmem-core takes care 505 * to keep pages in the required zone during swap-in. 506 */ 507 struct page **drm_gem_get_pages(struct drm_gem_object *obj) 508 { 509 struct address_space *mapping; 510 struct page *p, **pages; 511 int i, npages; 512 513 /* This is the shared memory object that backs the GEM resource */ 514 mapping = file_inode(obj->filp)->i_mapping; 515 516 /* We already BUG_ON() for non-page-aligned sizes in 517 * drm_gem_object_init(), so we should never hit this unless 518 * driver author is doing something really wrong: 519 */ 520 WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0); 521 522 npages = obj->size >> PAGE_SHIFT; 523 524 pages = drm_malloc_ab(npages, sizeof(struct page *)); 525 if (pages == NULL) 526 return ERR_PTR(-ENOMEM); 527 528 for (i = 0; i < npages; i++) { 529 p = shmem_read_mapping_page(mapping, i); 530 if (IS_ERR(p)) 531 goto fail; 532 pages[i] = p; 533 534 /* Make sure shmem keeps __GFP_DMA32 allocated pages in the 535 * correct region during swapin. Note that this requires 536 * __GFP_DMA32 to be set in mapping_gfp_mask(inode->i_mapping) 537 * so shmem can relocate pages during swapin if required. 538 */ 539 BUG_ON(mapping_gfp_constraint(mapping, __GFP_DMA32) && 540 (page_to_pfn(p) >= 0x00100000UL)); 541 } 542 543 return pages; 544 545 fail: 546 while (i--) 547 put_page(pages[i]); 548 549 drm_free_large(pages); 550 return ERR_CAST(p); 551 } 552 EXPORT_SYMBOL(drm_gem_get_pages); 553 554 /** 555 * drm_gem_put_pages - helper to free backing pages for a GEM object 556 * @obj: obj in question 557 * @pages: pages to free 558 * @dirty: if true, pages will be marked as dirty 559 * @accessed: if true, the pages will be marked as accessed 560 */ 561 void drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages, 562 bool dirty, bool accessed) 563 { 564 int i, npages; 565 566 /* We already BUG_ON() for non-page-aligned sizes in 567 * drm_gem_object_init(), so we should never hit this unless 568 * driver author is doing something really wrong: 569 */ 570 WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0); 571 572 npages = obj->size >> PAGE_SHIFT; 573 574 for (i = 0; i < npages; i++) { 575 if (dirty) 576 set_page_dirty(pages[i]); 577 578 if (accessed) 579 mark_page_accessed(pages[i]); 580 581 /* Undo the reference we took when populating the table */ 582 put_page(pages[i]); 583 } 584 585 drm_free_large(pages); 586 } 587 EXPORT_SYMBOL(drm_gem_put_pages); 588 589 /** 590 * drm_gem_object_lookup - look up a GEM object from it's handle 591 * @dev: DRM device 592 * @filp: DRM file private date 593 * @handle: userspace handle 594 * 595 * Returns: 596 * 597 * A reference to the object named by the handle if such exists on @filp, NULL 598 * otherwise. 599 */ 600 struct drm_gem_object * 601 drm_gem_object_lookup(struct drm_device *dev, struct drm_file *filp, 602 u32 handle) 603 { 604 struct drm_gem_object *obj; 605 606 spin_lock(&filp->table_lock); 607 608 /* Check if we currently have a reference on the object */ 609 obj = idr_find(&filp->object_idr, handle); 610 if (obj == NULL) { 611 spin_unlock(&filp->table_lock); 612 return NULL; 613 } 614 615 drm_gem_object_reference(obj); 616 617 spin_unlock(&filp->table_lock); 618 619 return obj; 620 } 621 EXPORT_SYMBOL(drm_gem_object_lookup); 622 623 /** 624 * drm_gem_close_ioctl - implementation of the GEM_CLOSE ioctl 625 * @dev: drm_device 626 * @data: ioctl data 627 * @file_priv: drm file-private structure 628 * 629 * Releases the handle to an mm object. 630 */ 631 int 632 drm_gem_close_ioctl(struct drm_device *dev, void *data, 633 struct drm_file *file_priv) 634 { 635 struct drm_gem_close *args = data; 636 int ret; 637 638 if (!drm_core_check_feature(dev, DRIVER_GEM)) 639 return -ENODEV; 640 641 ret = drm_gem_handle_delete(file_priv, args->handle); 642 643 return ret; 644 } 645 646 /** 647 * drm_gem_flink_ioctl - implementation of the GEM_FLINK ioctl 648 * @dev: drm_device 649 * @data: ioctl data 650 * @file_priv: drm file-private structure 651 * 652 * Create a global name for an object, returning the name. 653 * 654 * Note that the name does not hold a reference; when the object 655 * is freed, the name goes away. 656 */ 657 int 658 drm_gem_flink_ioctl(struct drm_device *dev, void *data, 659 struct drm_file *file_priv) 660 { 661 struct drm_gem_flink *args = data; 662 struct drm_gem_object *obj; 663 int ret; 664 665 if (!drm_core_check_feature(dev, DRIVER_GEM)) 666 return -ENODEV; 667 668 obj = drm_gem_object_lookup(dev, file_priv, args->handle); 669 if (obj == NULL) 670 return -ENOENT; 671 672 mutex_lock(&dev->object_name_lock); 673 /* prevent races with concurrent gem_close. */ 674 if (obj->handle_count == 0) { 675 ret = -ENOENT; 676 goto err; 677 } 678 679 if (!obj->name) { 680 ret = idr_alloc(&dev->object_name_idr, obj, 1, 0, GFP_KERNEL); 681 if (ret < 0) 682 goto err; 683 684 obj->name = ret; 685 } 686 687 args->name = (uint64_t) obj->name; 688 ret = 0; 689 690 err: 691 mutex_unlock(&dev->object_name_lock); 692 drm_gem_object_unreference_unlocked(obj); 693 return ret; 694 } 695 696 /** 697 * drm_gem_open - implementation of the GEM_OPEN ioctl 698 * @dev: drm_device 699 * @data: ioctl data 700 * @file_priv: drm file-private structure 701 * 702 * Open an object using the global name, returning a handle and the size. 703 * 704 * This handle (of course) holds a reference to the object, so the object 705 * will not go away until the handle is deleted. 706 */ 707 int 708 drm_gem_open_ioctl(struct drm_device *dev, void *data, 709 struct drm_file *file_priv) 710 { 711 struct drm_gem_open *args = data; 712 struct drm_gem_object *obj; 713 int ret; 714 u32 handle; 715 716 if (!drm_core_check_feature(dev, DRIVER_GEM)) 717 return -ENODEV; 718 719 mutex_lock(&dev->object_name_lock); 720 obj = idr_find(&dev->object_name_idr, (int) args->name); 721 if (obj) { 722 drm_gem_object_reference(obj); 723 } else { 724 mutex_unlock(&dev->object_name_lock); 725 return -ENOENT; 726 } 727 728 /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */ 729 ret = drm_gem_handle_create_tail(file_priv, obj, &handle); 730 drm_gem_object_unreference_unlocked(obj); 731 if (ret) 732 return ret; 733 734 args->handle = handle; 735 args->size = obj->size; 736 737 return 0; 738 } 739 740 /** 741 * gem_gem_open - initalizes GEM file-private structures at devnode open time 742 * @dev: drm_device which is being opened by userspace 743 * @file_private: drm file-private structure to set up 744 * 745 * Called at device open time, sets up the structure for handling refcounting 746 * of mm objects. 747 */ 748 void 749 drm_gem_open(struct drm_device *dev, struct drm_file *file_private) 750 { 751 idr_init(&file_private->object_idr); 752 spin_lock_init(&file_private->table_lock); 753 } 754 755 /** 756 * drm_gem_release - release file-private GEM resources 757 * @dev: drm_device which is being closed by userspace 758 * @file_private: drm file-private structure to clean up 759 * 760 * Called at close time when the filp is going away. 761 * 762 * Releases any remaining references on objects by this filp. 763 */ 764 void 765 drm_gem_release(struct drm_device *dev, struct drm_file *file_private) 766 { 767 idr_for_each(&file_private->object_idr, 768 &drm_gem_object_release_handle, file_private); 769 idr_destroy(&file_private->object_idr); 770 } 771 772 /** 773 * drm_gem_object_release - release GEM buffer object resources 774 * @obj: GEM buffer object 775 * 776 * This releases any structures and resources used by @obj and is the invers of 777 * drm_gem_object_init(). 778 */ 779 void 780 drm_gem_object_release(struct drm_gem_object *obj) 781 { 782 WARN_ON(obj->dma_buf); 783 784 if (obj->filp) 785 fput(obj->filp); 786 787 drm_gem_free_mmap_offset(obj); 788 } 789 EXPORT_SYMBOL(drm_gem_object_release); 790 791 /** 792 * drm_gem_object_free - free a GEM object 793 * @kref: kref of the object to free 794 * 795 * Called after the last reference to the object has been lost. 796 * Must be called holding struct_ mutex 797 * 798 * Frees the object 799 */ 800 void 801 drm_gem_object_free(struct kref *kref) 802 { 803 struct drm_gem_object *obj = 804 container_of(kref, struct drm_gem_object, refcount); 805 struct drm_device *dev = obj->dev; 806 807 WARN_ON(!mutex_is_locked(&dev->struct_mutex)); 808 809 if (dev->driver->gem_free_object != NULL) 810 dev->driver->gem_free_object(obj); 811 } 812 EXPORT_SYMBOL(drm_gem_object_free); 813 814 /** 815 * drm_gem_vm_open - vma->ops->open implementation for GEM 816 * @vma: VM area structure 817 * 818 * This function implements the #vm_operations_struct open() callback for GEM 819 * drivers. This must be used together with drm_gem_vm_close(). 820 */ 821 void drm_gem_vm_open(struct vm_area_struct *vma) 822 { 823 struct drm_gem_object *obj = vma->vm_private_data; 824 825 drm_gem_object_reference(obj); 826 } 827 EXPORT_SYMBOL(drm_gem_vm_open); 828 829 /** 830 * drm_gem_vm_close - vma->ops->close implementation for GEM 831 * @vma: VM area structure 832 * 833 * This function implements the #vm_operations_struct close() callback for GEM 834 * drivers. This must be used together with drm_gem_vm_open(). 835 */ 836 void drm_gem_vm_close(struct vm_area_struct *vma) 837 { 838 struct drm_gem_object *obj = vma->vm_private_data; 839 840 drm_gem_object_unreference_unlocked(obj); 841 } 842 EXPORT_SYMBOL(drm_gem_vm_close); 843 844 /** 845 * drm_gem_mmap_obj - memory map a GEM object 846 * @obj: the GEM object to map 847 * @obj_size: the object size to be mapped, in bytes 848 * @vma: VMA for the area to be mapped 849 * 850 * Set up the VMA to prepare mapping of the GEM object using the gem_vm_ops 851 * provided by the driver. Depending on their requirements, drivers can either 852 * provide a fault handler in their gem_vm_ops (in which case any accesses to 853 * the object will be trapped, to perform migration, GTT binding, surface 854 * register allocation, or performance monitoring), or mmap the buffer memory 855 * synchronously after calling drm_gem_mmap_obj. 856 * 857 * This function is mainly intended to implement the DMABUF mmap operation, when 858 * the GEM object is not looked up based on its fake offset. To implement the 859 * DRM mmap operation, drivers should use the drm_gem_mmap() function. 860 * 861 * drm_gem_mmap_obj() assumes the user is granted access to the buffer while 862 * drm_gem_mmap() prevents unprivileged users from mapping random objects. So 863 * callers must verify access restrictions before calling this helper. 864 * 865 * Return 0 or success or -EINVAL if the object size is smaller than the VMA 866 * size, or if no gem_vm_ops are provided. 867 */ 868 int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size, 869 struct vm_area_struct *vma) 870 { 871 struct drm_device *dev = obj->dev; 872 873 /* Check for valid size. */ 874 if (obj_size < vma->vm_end - vma->vm_start) 875 return -EINVAL; 876 877 if (!dev->driver->gem_vm_ops) 878 return -EINVAL; 879 880 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; 881 vma->vm_ops = dev->driver->gem_vm_ops; 882 vma->vm_private_data = obj; 883 vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags)); 884 885 /* Take a ref for this mapping of the object, so that the fault 886 * handler can dereference the mmap offset's pointer to the object. 887 * This reference is cleaned up by the corresponding vm_close 888 * (which should happen whether the vma was created by this call, or 889 * by a vm_open due to mremap or partial unmap or whatever). 890 */ 891 drm_gem_object_reference(obj); 892 893 return 0; 894 } 895 EXPORT_SYMBOL(drm_gem_mmap_obj); 896 897 /** 898 * drm_gem_mmap - memory map routine for GEM objects 899 * @filp: DRM file pointer 900 * @vma: VMA for the area to be mapped 901 * 902 * If a driver supports GEM object mapping, mmap calls on the DRM file 903 * descriptor will end up here. 904 * 905 * Look up the GEM object based on the offset passed in (vma->vm_pgoff will 906 * contain the fake offset we created when the GTT map ioctl was called on 907 * the object) and map it with a call to drm_gem_mmap_obj(). 908 * 909 * If the caller is not granted access to the buffer object, the mmap will fail 910 * with EACCES. Please see the vma manager for more information. 911 */ 912 int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma) 913 { 914 struct drm_file *priv = filp->private_data; 915 struct drm_device *dev = priv->minor->dev; 916 struct drm_gem_object *obj = NULL; 917 struct drm_vma_offset_node *node; 918 int ret; 919 920 if (drm_device_is_unplugged(dev)) 921 return -ENODEV; 922 923 drm_vma_offset_lock_lookup(dev->vma_offset_manager); 924 node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager, 925 vma->vm_pgoff, 926 vma_pages(vma)); 927 if (likely(node)) { 928 obj = container_of(node, struct drm_gem_object, vma_node); 929 /* 930 * When the object is being freed, after it hits 0-refcnt it 931 * proceeds to tear down the object. In the process it will 932 * attempt to remove the VMA offset and so acquire this 933 * mgr->vm_lock. Therefore if we find an object with a 0-refcnt 934 * that matches our range, we know it is in the process of being 935 * destroyed and will be freed as soon as we release the lock - 936 * so we have to check for the 0-refcnted object and treat it as 937 * invalid. 938 */ 939 if (!kref_get_unless_zero(&obj->refcount)) 940 obj = NULL; 941 } 942 drm_vma_offset_unlock_lookup(dev->vma_offset_manager); 943 944 if (!obj) 945 return -EINVAL; 946 947 if (!drm_vma_node_is_allowed(node, filp)) { 948 drm_gem_object_unreference_unlocked(obj); 949 return -EACCES; 950 } 951 952 ret = drm_gem_mmap_obj(obj, drm_vma_node_size(node) << PAGE_SHIFT, 953 vma); 954 955 drm_gem_object_unreference_unlocked(obj); 956 957 return ret; 958 } 959 EXPORT_SYMBOL(drm_gem_mmap); 960