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 42 /** @file drm_gem.c 43 * 44 * This file provides some of the base ioctls and library routines for 45 * the graphics memory manager implemented by each device driver. 46 * 47 * Because various devices have different requirements in terms of 48 * synchronization and migration strategies, implementing that is left up to 49 * the driver, and all that the general API provides should be generic -- 50 * allocating objects, reading/writing data with the cpu, freeing objects. 51 * Even there, platform-dependent optimizations for reading/writing data with 52 * the CPU mean we'll likely hook those out to driver-specific calls. However, 53 * the DRI2 implementation wants to have at least allocate/mmap be generic. 54 * 55 * The goal was to have swap-backed object allocation managed through 56 * struct file. However, file descriptors as handles to a struct file have 57 * two major failings: 58 * - Process limits prevent more than 1024 or so being used at a time by 59 * default. 60 * - Inability to allocate high fds will aggravate the X Server's select() 61 * handling, and likely that of many GL client applications as well. 62 * 63 * This led to a plan of using our own integer IDs (called handles, following 64 * DRM terminology) to mimic fds, and implement the fd syscalls we need as 65 * ioctls. The objects themselves will still include the struct file so 66 * that we can transition to fds if the required kernel infrastructure shows 67 * up at a later date, and as our interface with shmfs for memory allocation. 68 */ 69 70 /* 71 * We make up offsets for buffer objects so we can recognize them at 72 * mmap time. 73 */ 74 75 /* pgoff in mmap is an unsigned long, so we need to make sure that 76 * the faked up offset will fit 77 */ 78 79 #if BITS_PER_LONG == 64 80 #define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFFUL >> PAGE_SHIFT) + 1) 81 #define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFFUL >> PAGE_SHIFT) * 16) 82 #else 83 #define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFUL >> PAGE_SHIFT) + 1) 84 #define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFUL >> PAGE_SHIFT) * 16) 85 #endif 86 87 /** 88 * Initialize the GEM device fields 89 */ 90 91 int 92 drm_gem_init(struct drm_device *dev) 93 { 94 struct drm_gem_mm *mm; 95 96 spin_lock_init(&dev->object_name_lock); 97 idr_init(&dev->object_name_idr); 98 99 mm = kzalloc(sizeof(struct drm_gem_mm), GFP_KERNEL); 100 if (!mm) { 101 DRM_ERROR("out of memory\n"); 102 return -ENOMEM; 103 } 104 105 dev->mm_private = mm; 106 drm_vma_offset_manager_init(&mm->vma_manager, 107 DRM_FILE_PAGE_OFFSET_START, 108 DRM_FILE_PAGE_OFFSET_SIZE); 109 110 return 0; 111 } 112 113 void 114 drm_gem_destroy(struct drm_device *dev) 115 { 116 struct drm_gem_mm *mm = dev->mm_private; 117 118 drm_vma_offset_manager_destroy(&mm->vma_manager); 119 kfree(mm); 120 dev->mm_private = NULL; 121 } 122 123 /** 124 * Initialize an already allocated GEM object of the specified size with 125 * shmfs backing store. 126 */ 127 int drm_gem_object_init(struct drm_device *dev, 128 struct drm_gem_object *obj, size_t size) 129 { 130 struct file *filp; 131 132 filp = shmem_file_setup("drm mm object", size, VM_NORESERVE); 133 if (IS_ERR(filp)) 134 return PTR_ERR(filp); 135 136 drm_gem_private_object_init(dev, obj, size); 137 obj->filp = filp; 138 139 return 0; 140 } 141 EXPORT_SYMBOL(drm_gem_object_init); 142 143 /** 144 * Initialize an already allocated GEM object of the specified size with 145 * no GEM provided backing store. Instead the caller is responsible for 146 * backing the object and handling it. 147 */ 148 void drm_gem_private_object_init(struct drm_device *dev, 149 struct drm_gem_object *obj, size_t size) 150 { 151 BUG_ON((size & (PAGE_SIZE - 1)) != 0); 152 153 obj->dev = dev; 154 obj->filp = NULL; 155 156 kref_init(&obj->refcount); 157 atomic_set(&obj->handle_count, 0); 158 obj->size = size; 159 } 160 EXPORT_SYMBOL(drm_gem_private_object_init); 161 162 /** 163 * Allocate a GEM object of the specified size with shmfs backing store 164 */ 165 struct drm_gem_object * 166 drm_gem_object_alloc(struct drm_device *dev, size_t size) 167 { 168 struct drm_gem_object *obj; 169 170 obj = kzalloc(sizeof(*obj), GFP_KERNEL); 171 if (!obj) 172 goto free; 173 174 if (drm_gem_object_init(dev, obj, size) != 0) 175 goto free; 176 177 if (dev->driver->gem_init_object != NULL && 178 dev->driver->gem_init_object(obj) != 0) { 179 goto fput; 180 } 181 return obj; 182 fput: 183 /* Object_init mangles the global counters - readjust them. */ 184 fput(obj->filp); 185 free: 186 kfree(obj); 187 return NULL; 188 } 189 EXPORT_SYMBOL(drm_gem_object_alloc); 190 191 static void 192 drm_gem_remove_prime_handles(struct drm_gem_object *obj, struct drm_file *filp) 193 { 194 if (obj->import_attach) { 195 drm_prime_remove_buf_handle(&filp->prime, 196 obj->import_attach->dmabuf); 197 } 198 if (obj->export_dma_buf) { 199 drm_prime_remove_buf_handle(&filp->prime, 200 obj->export_dma_buf); 201 } 202 } 203 204 /** 205 * Removes the mapping from handle to filp for this object. 206 */ 207 int 208 drm_gem_handle_delete(struct drm_file *filp, u32 handle) 209 { 210 struct drm_device *dev; 211 struct drm_gem_object *obj; 212 213 /* This is gross. The idr system doesn't let us try a delete and 214 * return an error code. It just spews if you fail at deleting. 215 * So, we have to grab a lock around finding the object and then 216 * doing the delete on it and dropping the refcount, or the user 217 * could race us to double-decrement the refcount and cause a 218 * use-after-free later. Given the frequency of our handle lookups, 219 * we may want to use ida for number allocation and a hash table 220 * for the pointers, anyway. 221 */ 222 spin_lock(&filp->table_lock); 223 224 /* Check if we currently have a reference on the object */ 225 obj = idr_find(&filp->object_idr, handle); 226 if (obj == NULL) { 227 spin_unlock(&filp->table_lock); 228 return -EINVAL; 229 } 230 dev = obj->dev; 231 232 /* Release reference and decrement refcount. */ 233 idr_remove(&filp->object_idr, handle); 234 spin_unlock(&filp->table_lock); 235 236 drm_gem_remove_prime_handles(obj, filp); 237 238 if (dev->driver->gem_close_object) 239 dev->driver->gem_close_object(obj, filp); 240 drm_gem_object_handle_unreference_unlocked(obj); 241 242 return 0; 243 } 244 EXPORT_SYMBOL(drm_gem_handle_delete); 245 246 /** 247 * drm_gem_dumb_destroy - dumb fb callback helper for gem based drivers 248 * 249 * This implements the ->dumb_destroy kms driver callback for drivers which use 250 * gem to manage their backing storage. 251 */ 252 int drm_gem_dumb_destroy(struct drm_file *file, 253 struct drm_device *dev, 254 uint32_t handle) 255 { 256 return drm_gem_handle_delete(file, handle); 257 } 258 EXPORT_SYMBOL(drm_gem_dumb_destroy); 259 260 /** 261 * Create a handle for this object. This adds a handle reference 262 * to the object, which includes a regular reference count. Callers 263 * will likely want to dereference the object afterwards. 264 */ 265 int 266 drm_gem_handle_create(struct drm_file *file_priv, 267 struct drm_gem_object *obj, 268 u32 *handlep) 269 { 270 struct drm_device *dev = obj->dev; 271 int ret; 272 273 /* 274 * Get the user-visible handle using idr. Preload and perform 275 * allocation under our spinlock. 276 */ 277 idr_preload(GFP_KERNEL); 278 spin_lock(&file_priv->table_lock); 279 280 ret = idr_alloc(&file_priv->object_idr, obj, 1, 0, GFP_NOWAIT); 281 282 spin_unlock(&file_priv->table_lock); 283 idr_preload_end(); 284 if (ret < 0) 285 return ret; 286 *handlep = ret; 287 288 drm_gem_object_handle_reference(obj); 289 290 if (dev->driver->gem_open_object) { 291 ret = dev->driver->gem_open_object(obj, file_priv); 292 if (ret) { 293 drm_gem_handle_delete(file_priv, *handlep); 294 return ret; 295 } 296 } 297 298 return 0; 299 } 300 EXPORT_SYMBOL(drm_gem_handle_create); 301 302 303 /** 304 * drm_gem_free_mmap_offset - release a fake mmap offset for an object 305 * @obj: obj in question 306 * 307 * This routine frees fake offsets allocated by drm_gem_create_mmap_offset(). 308 */ 309 void 310 drm_gem_free_mmap_offset(struct drm_gem_object *obj) 311 { 312 struct drm_device *dev = obj->dev; 313 struct drm_gem_mm *mm = dev->mm_private; 314 315 drm_vma_offset_remove(&mm->vma_manager, &obj->vma_node); 316 } 317 EXPORT_SYMBOL(drm_gem_free_mmap_offset); 318 319 /** 320 * drm_gem_create_mmap_offset - create a fake mmap offset for an object 321 * @obj: obj in question 322 * 323 * GEM memory mapping works by handing back to userspace a fake mmap offset 324 * it can use in a subsequent mmap(2) call. The DRM core code then looks 325 * up the object based on the offset and sets up the various memory mapping 326 * structures. 327 * 328 * This routine allocates and attaches a fake offset for @obj. 329 */ 330 int 331 drm_gem_create_mmap_offset(struct drm_gem_object *obj) 332 { 333 struct drm_device *dev = obj->dev; 334 struct drm_gem_mm *mm = dev->mm_private; 335 336 return drm_vma_offset_add(&mm->vma_manager, &obj->vma_node, 337 obj->size / PAGE_SIZE); 338 } 339 EXPORT_SYMBOL(drm_gem_create_mmap_offset); 340 341 /** Returns a reference to the object named by the handle. */ 342 struct drm_gem_object * 343 drm_gem_object_lookup(struct drm_device *dev, struct drm_file *filp, 344 u32 handle) 345 { 346 struct drm_gem_object *obj; 347 348 spin_lock(&filp->table_lock); 349 350 /* Check if we currently have a reference on the object */ 351 obj = idr_find(&filp->object_idr, handle); 352 if (obj == NULL) { 353 spin_unlock(&filp->table_lock); 354 return NULL; 355 } 356 357 drm_gem_object_reference(obj); 358 359 spin_unlock(&filp->table_lock); 360 361 return obj; 362 } 363 EXPORT_SYMBOL(drm_gem_object_lookup); 364 365 /** 366 * Releases the handle to an mm object. 367 */ 368 int 369 drm_gem_close_ioctl(struct drm_device *dev, void *data, 370 struct drm_file *file_priv) 371 { 372 struct drm_gem_close *args = data; 373 int ret; 374 375 if (!(dev->driver->driver_features & DRIVER_GEM)) 376 return -ENODEV; 377 378 ret = drm_gem_handle_delete(file_priv, args->handle); 379 380 return ret; 381 } 382 383 /** 384 * Create a global name for an object, returning the name. 385 * 386 * Note that the name does not hold a reference; when the object 387 * is freed, the name goes away. 388 */ 389 int 390 drm_gem_flink_ioctl(struct drm_device *dev, void *data, 391 struct drm_file *file_priv) 392 { 393 struct drm_gem_flink *args = data; 394 struct drm_gem_object *obj; 395 int ret; 396 397 if (!(dev->driver->driver_features & DRIVER_GEM)) 398 return -ENODEV; 399 400 obj = drm_gem_object_lookup(dev, file_priv, args->handle); 401 if (obj == NULL) 402 return -ENOENT; 403 404 idr_preload(GFP_KERNEL); 405 spin_lock(&dev->object_name_lock); 406 if (!obj->name) { 407 ret = idr_alloc(&dev->object_name_idr, obj, 1, 0, GFP_NOWAIT); 408 if (ret < 0) 409 goto err; 410 411 obj->name = ret; 412 413 /* Allocate a reference for the name table. */ 414 drm_gem_object_reference(obj); 415 } 416 417 args->name = (uint64_t) obj->name; 418 ret = 0; 419 420 err: 421 spin_unlock(&dev->object_name_lock); 422 idr_preload_end(); 423 drm_gem_object_unreference_unlocked(obj); 424 return ret; 425 } 426 427 /** 428 * Open an object using the global name, returning a handle and the size. 429 * 430 * This handle (of course) holds a reference to the object, so the object 431 * will not go away until the handle is deleted. 432 */ 433 int 434 drm_gem_open_ioctl(struct drm_device *dev, void *data, 435 struct drm_file *file_priv) 436 { 437 struct drm_gem_open *args = data; 438 struct drm_gem_object *obj; 439 int ret; 440 u32 handle; 441 442 if (!(dev->driver->driver_features & DRIVER_GEM)) 443 return -ENODEV; 444 445 spin_lock(&dev->object_name_lock); 446 obj = idr_find(&dev->object_name_idr, (int) args->name); 447 if (obj) 448 drm_gem_object_reference(obj); 449 spin_unlock(&dev->object_name_lock); 450 if (!obj) 451 return -ENOENT; 452 453 ret = drm_gem_handle_create(file_priv, obj, &handle); 454 drm_gem_object_unreference_unlocked(obj); 455 if (ret) 456 return ret; 457 458 args->handle = handle; 459 args->size = obj->size; 460 461 return 0; 462 } 463 464 /** 465 * Called at device open time, sets up the structure for handling refcounting 466 * of mm objects. 467 */ 468 void 469 drm_gem_open(struct drm_device *dev, struct drm_file *file_private) 470 { 471 idr_init(&file_private->object_idr); 472 spin_lock_init(&file_private->table_lock); 473 } 474 475 /** 476 * Called at device close to release the file's 477 * handle references on objects. 478 */ 479 static int 480 drm_gem_object_release_handle(int id, void *ptr, void *data) 481 { 482 struct drm_file *file_priv = data; 483 struct drm_gem_object *obj = ptr; 484 struct drm_device *dev = obj->dev; 485 486 drm_gem_remove_prime_handles(obj, file_priv); 487 488 if (dev->driver->gem_close_object) 489 dev->driver->gem_close_object(obj, file_priv); 490 491 drm_gem_object_handle_unreference_unlocked(obj); 492 493 return 0; 494 } 495 496 /** 497 * Called at close time when the filp is going away. 498 * 499 * Releases any remaining references on objects by this filp. 500 */ 501 void 502 drm_gem_release(struct drm_device *dev, struct drm_file *file_private) 503 { 504 idr_for_each(&file_private->object_idr, 505 &drm_gem_object_release_handle, file_private); 506 idr_destroy(&file_private->object_idr); 507 } 508 509 void 510 drm_gem_object_release(struct drm_gem_object *obj) 511 { 512 if (obj->filp) 513 fput(obj->filp); 514 } 515 EXPORT_SYMBOL(drm_gem_object_release); 516 517 /** 518 * Called after the last reference to the object has been lost. 519 * Must be called holding struct_ mutex 520 * 521 * Frees the object 522 */ 523 void 524 drm_gem_object_free(struct kref *kref) 525 { 526 struct drm_gem_object *obj = (struct drm_gem_object *) kref; 527 struct drm_device *dev = obj->dev; 528 529 BUG_ON(!mutex_is_locked(&dev->struct_mutex)); 530 531 if (dev->driver->gem_free_object != NULL) 532 dev->driver->gem_free_object(obj); 533 } 534 EXPORT_SYMBOL(drm_gem_object_free); 535 536 static void drm_gem_object_ref_bug(struct kref *list_kref) 537 { 538 BUG(); 539 } 540 541 /** 542 * Called after the last handle to the object has been closed 543 * 544 * Removes any name for the object. Note that this must be 545 * called before drm_gem_object_free or we'll be touching 546 * freed memory 547 */ 548 void drm_gem_object_handle_free(struct drm_gem_object *obj) 549 { 550 struct drm_device *dev = obj->dev; 551 552 /* Remove any name for this object */ 553 spin_lock(&dev->object_name_lock); 554 if (obj->name) { 555 idr_remove(&dev->object_name_idr, obj->name); 556 obj->name = 0; 557 spin_unlock(&dev->object_name_lock); 558 /* 559 * The object name held a reference to this object, drop 560 * that now. 561 * 562 * This cannot be the last reference, since the handle holds one too. 563 */ 564 kref_put(&obj->refcount, drm_gem_object_ref_bug); 565 } else 566 spin_unlock(&dev->object_name_lock); 567 568 } 569 EXPORT_SYMBOL(drm_gem_object_handle_free); 570 571 void drm_gem_vm_open(struct vm_area_struct *vma) 572 { 573 struct drm_gem_object *obj = vma->vm_private_data; 574 575 drm_gem_object_reference(obj); 576 577 mutex_lock(&obj->dev->struct_mutex); 578 drm_vm_open_locked(obj->dev, vma); 579 mutex_unlock(&obj->dev->struct_mutex); 580 } 581 EXPORT_SYMBOL(drm_gem_vm_open); 582 583 void drm_gem_vm_close(struct vm_area_struct *vma) 584 { 585 struct drm_gem_object *obj = vma->vm_private_data; 586 struct drm_device *dev = obj->dev; 587 588 mutex_lock(&dev->struct_mutex); 589 drm_vm_close_locked(obj->dev, vma); 590 drm_gem_object_unreference(obj); 591 mutex_unlock(&dev->struct_mutex); 592 } 593 EXPORT_SYMBOL(drm_gem_vm_close); 594 595 /** 596 * drm_gem_mmap_obj - memory map a GEM object 597 * @obj: the GEM object to map 598 * @obj_size: the object size to be mapped, in bytes 599 * @vma: VMA for the area to be mapped 600 * 601 * Set up the VMA to prepare mapping of the GEM object using the gem_vm_ops 602 * provided by the driver. Depending on their requirements, drivers can either 603 * provide a fault handler in their gem_vm_ops (in which case any accesses to 604 * the object will be trapped, to perform migration, GTT binding, surface 605 * register allocation, or performance monitoring), or mmap the buffer memory 606 * synchronously after calling drm_gem_mmap_obj. 607 * 608 * This function is mainly intended to implement the DMABUF mmap operation, when 609 * the GEM object is not looked up based on its fake offset. To implement the 610 * DRM mmap operation, drivers should use the drm_gem_mmap() function. 611 * 612 * NOTE: This function has to be protected with dev->struct_mutex 613 * 614 * Return 0 or success or -EINVAL if the object size is smaller than the VMA 615 * size, or if no gem_vm_ops are provided. 616 */ 617 int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size, 618 struct vm_area_struct *vma) 619 { 620 struct drm_device *dev = obj->dev; 621 622 lockdep_assert_held(&dev->struct_mutex); 623 624 /* Check for valid size. */ 625 if (obj_size < vma->vm_end - vma->vm_start) 626 return -EINVAL; 627 628 if (!dev->driver->gem_vm_ops) 629 return -EINVAL; 630 631 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; 632 vma->vm_ops = dev->driver->gem_vm_ops; 633 vma->vm_private_data = obj; 634 vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags)); 635 636 /* Take a ref for this mapping of the object, so that the fault 637 * handler can dereference the mmap offset's pointer to the object. 638 * This reference is cleaned up by the corresponding vm_close 639 * (which should happen whether the vma was created by this call, or 640 * by a vm_open due to mremap or partial unmap or whatever). 641 */ 642 drm_gem_object_reference(obj); 643 644 drm_vm_open_locked(dev, vma); 645 return 0; 646 } 647 EXPORT_SYMBOL(drm_gem_mmap_obj); 648 649 /** 650 * drm_gem_mmap - memory map routine for GEM objects 651 * @filp: DRM file pointer 652 * @vma: VMA for the area to be mapped 653 * 654 * If a driver supports GEM object mapping, mmap calls on the DRM file 655 * descriptor will end up here. 656 * 657 * Look up the GEM object based on the offset passed in (vma->vm_pgoff will 658 * contain the fake offset we created when the GTT map ioctl was called on 659 * the object) and map it with a call to drm_gem_mmap_obj(). 660 */ 661 int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma) 662 { 663 struct drm_file *priv = filp->private_data; 664 struct drm_device *dev = priv->minor->dev; 665 struct drm_gem_mm *mm = dev->mm_private; 666 struct drm_gem_object *obj; 667 struct drm_vma_offset_node *node; 668 int ret = 0; 669 670 if (drm_device_is_unplugged(dev)) 671 return -ENODEV; 672 673 mutex_lock(&dev->struct_mutex); 674 675 node = drm_vma_offset_exact_lookup(&mm->vma_manager, vma->vm_pgoff, 676 vma_pages(vma)); 677 if (!node) { 678 mutex_unlock(&dev->struct_mutex); 679 return drm_mmap(filp, vma); 680 } 681 682 obj = container_of(node, struct drm_gem_object, vma_node); 683 ret = drm_gem_mmap_obj(obj, drm_vma_node_size(node) << PAGE_SHIFT, vma); 684 685 mutex_unlock(&dev->struct_mutex); 686 687 return ret; 688 } 689 EXPORT_SYMBOL(drm_gem_mmap); 690