2 * Copyright © 2008 Intel Corporation
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:
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
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
24 * Eric Anholt <eric@anholt.net>
28 #include <linux/types.h>
29 #include <linux/slab.h>
31 #include <linux/uaccess.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>
40 #include <drm/drm_vma_manager.h>
41 #include <drm/drm_gem.h>
42 #include "drm_internal.h"
46 * This file provides some of the base ioctls and library routines for
47 * the graphics memory manager implemented by each device driver.
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.
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
60 * - Process limits prevent more than 1024 or so being used at a time by
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.
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.
73 * We make up offsets for buffer objects so we can recognize them at
77 /* pgoff in mmap is an unsigned long, so we need to make sure that
78 * the faked up offset will fit
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)
85 #define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFUL >> PAGE_SHIFT) + 1)
86 #define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFUL >> PAGE_SHIFT) * 16)
90 * drm_gem_init - Initialize the GEM device fields
91 * @dev: drm_devic structure to initialize
94 drm_gem_init(struct drm_device *dev)
96 struct drm_vma_offset_manager *vma_offset_manager;
98 mutex_init(&dev->object_name_lock);
99 idr_init(&dev->object_name_idr);
101 vma_offset_manager = kzalloc(sizeof(*vma_offset_manager), GFP_KERNEL);
102 if (!vma_offset_manager) {
103 DRM_ERROR("out of memory\n");
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);
116 drm_gem_destroy(struct drm_device *dev)
119 drm_vma_offset_manager_destroy(dev->vma_offset_manager);
120 kfree(dev->vma_offset_manager);
121 dev->vma_offset_manager = NULL;
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
130 * Initialize an already allocated GEM object of the specified size with
131 * shmfs backing store.
133 int drm_gem_object_init(struct drm_device *dev,
134 struct drm_gem_object *obj, size_t size)
138 drm_gem_private_object_init(dev, obj, size);
140 filp = shmem_file_setup("drm mm object", size, VM_NORESERVE);
142 return PTR_ERR(filp);
148 EXPORT_SYMBOL(drm_gem_object_init);
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
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.
160 void drm_gem_private_object_init(struct drm_device *dev,
161 struct drm_gem_object *obj, size_t size)
163 BUG_ON((size & (PAGE_SIZE - 1)) != 0);
168 kref_init(&obj->refcount);
169 obj->handle_count = 0;
171 drm_vma_node_reset(&obj->vma_node);
173 EXPORT_SYMBOL(drm_gem_private_object_init);
176 drm_gem_remove_prime_handles(struct drm_gem_object *obj, struct drm_file *filp)
179 * Note: obj->dma_buf can't disappear as long as we still hold a
180 * handle reference in obj->handle_count.
182 mutex_lock(&filp->prime.lock);
184 drm_prime_remove_buf_handle_locked(&filp->prime,
187 mutex_unlock(&filp->prime.lock);
191 * drm_gem_object_handle_free - release resources bound to userspace handles
192 * @obj: GEM object to clean up.
194 * Called after the last handle to the object has been closed
196 * Removes any name for the object. Note that this must be
197 * called before drm_gem_object_free or we'll be touching
200 static void drm_gem_object_handle_free(struct drm_gem_object *obj)
202 struct drm_device *dev = obj->dev;
204 /* Remove any name for this object */
206 idr_remove(&dev->object_name_idr, obj->name);
211 static void drm_gem_object_exported_dma_buf_free(struct drm_gem_object *obj)
213 /* Unbreak the reference cycle if we have an exported dma_buf. */
215 dma_buf_put(obj->dma_buf);
221 drm_gem_object_handle_put_unlocked(struct drm_gem_object *obj)
223 struct drm_device *dev = obj->dev;
226 if (WARN_ON(obj->handle_count == 0))
230 * Must bump handle count first as this may be the last
231 * ref, in which case the object would disappear before we
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);
241 mutex_unlock(&dev->object_name_lock);
244 drm_gem_object_put_unlocked(obj);
248 * Called at device or object close to release the file's
249 * handle references on objects.
252 drm_gem_object_release_handle(int id, void *ptr, void *data)
254 struct drm_file *file_priv = data;
255 struct drm_gem_object *obj = ptr;
256 struct drm_device *dev = obj->dev;
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);
262 if (dev->driver->gem_close_object)
263 dev->driver->gem_close_object(obj, file_priv);
265 drm_gem_object_handle_put_unlocked(obj);
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
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.
280 drm_gem_handle_delete(struct drm_file *filp, u32 handle)
282 struct drm_gem_object *obj;
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.
293 spin_lock(&filp->table_lock);
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))
301 /* Release driver's reference and decrement refcount. */
302 drm_gem_object_release_handle(handle, obj, filp);
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);
311 EXPORT_SYMBOL(drm_gem_handle_delete);
314 * drm_gem_dumb_map_offset - return the fake mmap offset for a gem object
315 * @file: drm file-private structure containing the gem object
316 * @dev: corresponding drm_device
317 * @handle: gem object handle
318 * @offset: return location for the fake mmap offset
320 * This implements the &drm_driver.dumb_map_offset kms driver callback for
321 * drivers which use gem to manage their backing storage.
324 * 0 on success or a negative error code on failure.
326 int drm_gem_dumb_map_offset(struct drm_file *file, struct drm_device *dev,
327 u32 handle, u64 *offset)
329 struct drm_gem_object *obj;
332 obj = drm_gem_object_lookup(file, handle);
336 ret = drm_gem_create_mmap_offset(obj);
340 *offset = drm_vma_node_offset_addr(&obj->vma_node);
342 drm_gem_object_put_unlocked(obj);
346 EXPORT_SYMBOL_GPL(drm_gem_dumb_map_offset);
349 * drm_gem_dumb_destroy - dumb fb callback helper for gem based drivers
350 * @file: drm file-private structure to remove the dumb handle from
351 * @dev: corresponding drm_device
352 * @handle: the dumb handle to remove
354 * This implements the &drm_driver.dumb_destroy kms driver callback for drivers
355 * which use gem to manage their backing storage.
357 int drm_gem_dumb_destroy(struct drm_file *file,
358 struct drm_device *dev,
361 return drm_gem_handle_delete(file, handle);
363 EXPORT_SYMBOL(drm_gem_dumb_destroy);
366 * drm_gem_handle_create_tail - internal functions to create a handle
367 * @file_priv: drm file-private structure to register the handle for
368 * @obj: object to register
369 * @handlep: pointer to return the created handle to the caller
371 * This expects the &drm_device.object_name_lock to be held already and will
372 * drop it before returning. Used to avoid races in establishing new handles
373 * when importing an object from either an flink name or a dma-buf.
375 * Handles must be release again through drm_gem_handle_delete(). This is done
376 * when userspace closes @file_priv for all attached handles, or through the
377 * GEM_CLOSE ioctl for individual handles.
380 drm_gem_handle_create_tail(struct drm_file *file_priv,
381 struct drm_gem_object *obj,
384 struct drm_device *dev = obj->dev;
388 WARN_ON(!mutex_is_locked(&dev->object_name_lock));
389 if (obj->handle_count++ == 0)
390 drm_gem_object_get(obj);
393 * Get the user-visible handle using idr. Preload and perform
394 * allocation under our spinlock.
396 idr_preload(GFP_KERNEL);
397 spin_lock(&file_priv->table_lock);
399 ret = idr_alloc(&file_priv->object_idr, obj, 1, 0, GFP_NOWAIT);
401 spin_unlock(&file_priv->table_lock);
404 mutex_unlock(&dev->object_name_lock);
410 ret = drm_vma_node_allow(&obj->vma_node, file_priv);
414 if (dev->driver->gem_open_object) {
415 ret = dev->driver->gem_open_object(obj, file_priv);
424 drm_vma_node_revoke(&obj->vma_node, file_priv);
426 spin_lock(&file_priv->table_lock);
427 idr_remove(&file_priv->object_idr, handle);
428 spin_unlock(&file_priv->table_lock);
430 drm_gem_object_handle_put_unlocked(obj);
435 * drm_gem_handle_create - create a gem handle for an object
436 * @file_priv: drm file-private structure to register the handle for
437 * @obj: object to register
438 * @handlep: pionter to return the created handle to the caller
440 * Create a handle for this object. This adds a handle reference
441 * to the object, which includes a regular reference count. Callers
442 * will likely want to dereference the object afterwards.
444 int drm_gem_handle_create(struct drm_file *file_priv,
445 struct drm_gem_object *obj,
448 mutex_lock(&obj->dev->object_name_lock);
450 return drm_gem_handle_create_tail(file_priv, obj, handlep);
452 EXPORT_SYMBOL(drm_gem_handle_create);
456 * drm_gem_free_mmap_offset - release a fake mmap offset for an object
457 * @obj: obj in question
459 * This routine frees fake offsets allocated by drm_gem_create_mmap_offset().
461 * Note that drm_gem_object_release() already calls this function, so drivers
462 * don't have to take care of releasing the mmap offset themselves when freeing
466 drm_gem_free_mmap_offset(struct drm_gem_object *obj)
468 struct drm_device *dev = obj->dev;
470 drm_vma_offset_remove(dev->vma_offset_manager, &obj->vma_node);
472 EXPORT_SYMBOL(drm_gem_free_mmap_offset);
475 * drm_gem_create_mmap_offset_size - create a fake mmap offset for an object
476 * @obj: obj in question
477 * @size: the virtual size
479 * GEM memory mapping works by handing back to userspace a fake mmap offset
480 * it can use in a subsequent mmap(2) call. The DRM core code then looks
481 * up the object based on the offset and sets up the various memory mapping
484 * This routine allocates and attaches a fake offset for @obj, in cases where
485 * the virtual size differs from the physical size (ie. &drm_gem_object.size).
486 * Otherwise just use drm_gem_create_mmap_offset().
488 * This function is idempotent and handles an already allocated mmap offset
489 * transparently. Drivers do not need to check for this case.
492 drm_gem_create_mmap_offset_size(struct drm_gem_object *obj, size_t size)
494 struct drm_device *dev = obj->dev;
496 return drm_vma_offset_add(dev->vma_offset_manager, &obj->vma_node,
499 EXPORT_SYMBOL(drm_gem_create_mmap_offset_size);
502 * drm_gem_create_mmap_offset - create a fake mmap offset for an object
503 * @obj: obj in question
505 * GEM memory mapping works by handing back to userspace a fake mmap offset
506 * it can use in a subsequent mmap(2) call. The DRM core code then looks
507 * up the object based on the offset and sets up the various memory mapping
510 * This routine allocates and attaches a fake offset for @obj.
512 * Drivers can call drm_gem_free_mmap_offset() before freeing @obj to release
513 * the fake offset again.
515 int drm_gem_create_mmap_offset(struct drm_gem_object *obj)
517 return drm_gem_create_mmap_offset_size(obj, obj->size);
519 EXPORT_SYMBOL(drm_gem_create_mmap_offset);
522 * drm_gem_get_pages - helper to allocate backing pages for a GEM object
524 * @obj: obj in question
526 * This reads the page-array of the shmem-backing storage of the given gem
527 * object. An array of pages is returned. If a page is not allocated or
528 * swapped-out, this will allocate/swap-in the required pages. Note that the
529 * whole object is covered by the page-array and pinned in memory.
531 * Use drm_gem_put_pages() to release the array and unpin all pages.
533 * This uses the GFP-mask set on the shmem-mapping (see mapping_set_gfp_mask()).
534 * If you require other GFP-masks, you have to do those allocations yourself.
536 * Note that you are not allowed to change gfp-zones during runtime. That is,
537 * shmem_read_mapping_page_gfp() must be called with the same gfp_zone(gfp) as
538 * set during initialization. If you have special zone constraints, set them
539 * after drm_gem_init_object() via mapping_set_gfp_mask(). shmem-core takes care
540 * to keep pages in the required zone during swap-in.
542 struct page **drm_gem_get_pages(struct drm_gem_object *obj)
544 struct address_space *mapping;
545 struct page *p, **pages;
548 /* This is the shared memory object that backs the GEM resource */
549 mapping = obj->filp->f_mapping;
551 /* We already BUG_ON() for non-page-aligned sizes in
552 * drm_gem_object_init(), so we should never hit this unless
553 * driver author is doing something really wrong:
555 WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0);
557 npages = obj->size >> PAGE_SHIFT;
559 pages = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
561 return ERR_PTR(-ENOMEM);
563 for (i = 0; i < npages; i++) {
564 p = shmem_read_mapping_page(mapping, i);
569 /* Make sure shmem keeps __GFP_DMA32 allocated pages in the
570 * correct region during swapin. Note that this requires
571 * __GFP_DMA32 to be set in mapping_gfp_mask(inode->i_mapping)
572 * so shmem can relocate pages during swapin if required.
574 BUG_ON(mapping_gfp_constraint(mapping, __GFP_DMA32) &&
575 (page_to_pfn(p) >= 0x00100000UL));
587 EXPORT_SYMBOL(drm_gem_get_pages);
590 * drm_gem_put_pages - helper to free backing pages for a GEM object
591 * @obj: obj in question
592 * @pages: pages to free
593 * @dirty: if true, pages will be marked as dirty
594 * @accessed: if true, the pages will be marked as accessed
596 void drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages,
597 bool dirty, bool accessed)
601 /* We already BUG_ON() for non-page-aligned sizes in
602 * drm_gem_object_init(), so we should never hit this unless
603 * driver author is doing something really wrong:
605 WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0);
607 npages = obj->size >> PAGE_SHIFT;
609 for (i = 0; i < npages; i++) {
611 set_page_dirty(pages[i]);
614 mark_page_accessed(pages[i]);
616 /* Undo the reference we took when populating the table */
622 EXPORT_SYMBOL(drm_gem_put_pages);
625 * drm_gem_object_lookup - look up a GEM object from it's handle
626 * @filp: DRM file private date
627 * @handle: userspace handle
631 * A reference to the object named by the handle if such exists on @filp, NULL
634 struct drm_gem_object *
635 drm_gem_object_lookup(struct drm_file *filp, u32 handle)
637 struct drm_gem_object *obj;
639 spin_lock(&filp->table_lock);
641 /* Check if we currently have a reference on the object */
642 obj = idr_find(&filp->object_idr, handle);
644 drm_gem_object_get(obj);
646 spin_unlock(&filp->table_lock);
650 EXPORT_SYMBOL(drm_gem_object_lookup);
653 * drm_gem_close_ioctl - implementation of the GEM_CLOSE ioctl
656 * @file_priv: drm file-private structure
658 * Releases the handle to an mm object.
661 drm_gem_close_ioctl(struct drm_device *dev, void *data,
662 struct drm_file *file_priv)
664 struct drm_gem_close *args = data;
667 if (!drm_core_check_feature(dev, DRIVER_GEM))
670 ret = drm_gem_handle_delete(file_priv, args->handle);
676 * drm_gem_flink_ioctl - implementation of the GEM_FLINK ioctl
679 * @file_priv: drm file-private structure
681 * Create a global name for an object, returning the name.
683 * Note that the name does not hold a reference; when the object
684 * is freed, the name goes away.
687 drm_gem_flink_ioctl(struct drm_device *dev, void *data,
688 struct drm_file *file_priv)
690 struct drm_gem_flink *args = data;
691 struct drm_gem_object *obj;
694 if (!drm_core_check_feature(dev, DRIVER_GEM))
697 obj = drm_gem_object_lookup(file_priv, args->handle);
701 mutex_lock(&dev->object_name_lock);
702 /* prevent races with concurrent gem_close. */
703 if (obj->handle_count == 0) {
709 ret = idr_alloc(&dev->object_name_idr, obj, 1, 0, GFP_KERNEL);
716 args->name = (uint64_t) obj->name;
720 mutex_unlock(&dev->object_name_lock);
721 drm_gem_object_put_unlocked(obj);
726 * drm_gem_open - implementation of the GEM_OPEN ioctl
729 * @file_priv: drm file-private structure
731 * Open an object using the global name, returning a handle and the size.
733 * This handle (of course) holds a reference to the object, so the object
734 * will not go away until the handle is deleted.
737 drm_gem_open_ioctl(struct drm_device *dev, void *data,
738 struct drm_file *file_priv)
740 struct drm_gem_open *args = data;
741 struct drm_gem_object *obj;
745 if (!drm_core_check_feature(dev, DRIVER_GEM))
748 mutex_lock(&dev->object_name_lock);
749 obj = idr_find(&dev->object_name_idr, (int) args->name);
751 drm_gem_object_get(obj);
753 mutex_unlock(&dev->object_name_lock);
757 /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */
758 ret = drm_gem_handle_create_tail(file_priv, obj, &handle);
759 drm_gem_object_put_unlocked(obj);
763 args->handle = handle;
764 args->size = obj->size;
770 * gem_gem_open - initalizes GEM file-private structures at devnode open time
771 * @dev: drm_device which is being opened by userspace
772 * @file_private: drm file-private structure to set up
774 * Called at device open time, sets up the structure for handling refcounting
778 drm_gem_open(struct drm_device *dev, struct drm_file *file_private)
780 idr_init(&file_private->object_idr);
781 spin_lock_init(&file_private->table_lock);
785 * drm_gem_release - release file-private GEM resources
786 * @dev: drm_device which is being closed by userspace
787 * @file_private: drm file-private structure to clean up
789 * Called at close time when the filp is going away.
791 * Releases any remaining references on objects by this filp.
794 drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
796 idr_for_each(&file_private->object_idr,
797 &drm_gem_object_release_handle, file_private);
798 idr_destroy(&file_private->object_idr);
802 * drm_gem_object_release - release GEM buffer object resources
803 * @obj: GEM buffer object
805 * This releases any structures and resources used by @obj and is the invers of
806 * drm_gem_object_init().
809 drm_gem_object_release(struct drm_gem_object *obj)
811 WARN_ON(obj->dma_buf);
816 drm_gem_free_mmap_offset(obj);
818 EXPORT_SYMBOL(drm_gem_object_release);
821 * drm_gem_object_free - free a GEM object
822 * @kref: kref of the object to free
824 * Called after the last reference to the object has been lost.
825 * Must be called holding &drm_device.struct_mutex.
830 drm_gem_object_free(struct kref *kref)
832 struct drm_gem_object *obj =
833 container_of(kref, struct drm_gem_object, refcount);
834 struct drm_device *dev = obj->dev;
836 if (dev->driver->gem_free_object_unlocked) {
837 dev->driver->gem_free_object_unlocked(obj);
838 } else if (dev->driver->gem_free_object) {
839 WARN_ON(!mutex_is_locked(&dev->struct_mutex));
841 dev->driver->gem_free_object(obj);
844 EXPORT_SYMBOL(drm_gem_object_free);
847 * drm_gem_object_put_unlocked - drop a GEM buffer object reference
848 * @obj: GEM buffer object
850 * This releases a reference to @obj. Callers must not hold the
851 * &drm_device.struct_mutex lock when calling this function.
853 * See also __drm_gem_object_put().
856 drm_gem_object_put_unlocked(struct drm_gem_object *obj)
858 struct drm_device *dev;
865 if (dev->driver->gem_free_object_unlocked) {
866 kref_put(&obj->refcount, drm_gem_object_free);
868 might_lock(&dev->struct_mutex);
869 if (kref_put_mutex(&obj->refcount, drm_gem_object_free,
871 mutex_unlock(&dev->struct_mutex);
874 EXPORT_SYMBOL(drm_gem_object_put_unlocked);
877 * drm_gem_object_put - release a GEM buffer object reference
878 * @obj: GEM buffer object
880 * This releases a reference to @obj. Callers must hold the
881 * &drm_device.struct_mutex lock when calling this function, even when the
882 * driver doesn't use &drm_device.struct_mutex for anything.
884 * For drivers not encumbered with legacy locking use
885 * drm_gem_object_put_unlocked() instead.
888 drm_gem_object_put(struct drm_gem_object *obj)
891 WARN_ON(!mutex_is_locked(&obj->dev->struct_mutex));
893 kref_put(&obj->refcount, drm_gem_object_free);
896 EXPORT_SYMBOL(drm_gem_object_put);
899 * drm_gem_vm_open - vma->ops->open implementation for GEM
900 * @vma: VM area structure
902 * This function implements the #vm_operations_struct open() callback for GEM
903 * drivers. This must be used together with drm_gem_vm_close().
905 void drm_gem_vm_open(struct vm_area_struct *vma)
907 struct drm_gem_object *obj = vma->vm_private_data;
909 drm_gem_object_get(obj);
911 EXPORT_SYMBOL(drm_gem_vm_open);
914 * drm_gem_vm_close - vma->ops->close implementation for GEM
915 * @vma: VM area structure
917 * This function implements the #vm_operations_struct close() callback for GEM
918 * drivers. This must be used together with drm_gem_vm_open().
920 void drm_gem_vm_close(struct vm_area_struct *vma)
922 struct drm_gem_object *obj = vma->vm_private_data;
924 drm_gem_object_put_unlocked(obj);
926 EXPORT_SYMBOL(drm_gem_vm_close);
929 * drm_gem_mmap_obj - memory map a GEM object
930 * @obj: the GEM object to map
931 * @obj_size: the object size to be mapped, in bytes
932 * @vma: VMA for the area to be mapped
934 * Set up the VMA to prepare mapping of the GEM object using the gem_vm_ops
935 * provided by the driver. Depending on their requirements, drivers can either
936 * provide a fault handler in their gem_vm_ops (in which case any accesses to
937 * the object will be trapped, to perform migration, GTT binding, surface
938 * register allocation, or performance monitoring), or mmap the buffer memory
939 * synchronously after calling drm_gem_mmap_obj.
941 * This function is mainly intended to implement the DMABUF mmap operation, when
942 * the GEM object is not looked up based on its fake offset. To implement the
943 * DRM mmap operation, drivers should use the drm_gem_mmap() function.
945 * drm_gem_mmap_obj() assumes the user is granted access to the buffer while
946 * drm_gem_mmap() prevents unprivileged users from mapping random objects. So
947 * callers must verify access restrictions before calling this helper.
949 * Return 0 or success or -EINVAL if the object size is smaller than the VMA
950 * size, or if no gem_vm_ops are provided.
952 int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
953 struct vm_area_struct *vma)
955 struct drm_device *dev = obj->dev;
957 /* Check for valid size. */
958 if (obj_size < vma->vm_end - vma->vm_start)
961 if (!dev->driver->gem_vm_ops)
964 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
965 vma->vm_ops = dev->driver->gem_vm_ops;
966 vma->vm_private_data = obj;
967 vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
969 /* Take a ref for this mapping of the object, so that the fault
970 * handler can dereference the mmap offset's pointer to the object.
971 * This reference is cleaned up by the corresponding vm_close
972 * (which should happen whether the vma was created by this call, or
973 * by a vm_open due to mremap or partial unmap or whatever).
975 drm_gem_object_get(obj);
979 EXPORT_SYMBOL(drm_gem_mmap_obj);
982 * drm_gem_mmap - memory map routine for GEM objects
983 * @filp: DRM file pointer
984 * @vma: VMA for the area to be mapped
986 * If a driver supports GEM object mapping, mmap calls on the DRM file
987 * descriptor will end up here.
989 * Look up the GEM object based on the offset passed in (vma->vm_pgoff will
990 * contain the fake offset we created when the GTT map ioctl was called on
991 * the object) and map it with a call to drm_gem_mmap_obj().
993 * If the caller is not granted access to the buffer object, the mmap will fail
994 * with EACCES. Please see the vma manager for more information.
996 int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
998 struct drm_file *priv = filp->private_data;
999 struct drm_device *dev = priv->minor->dev;
1000 struct drm_gem_object *obj = NULL;
1001 struct drm_vma_offset_node *node;
1004 if (drm_dev_is_unplugged(dev))
1007 drm_vma_offset_lock_lookup(dev->vma_offset_manager);
1008 node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager,
1012 obj = container_of(node, struct drm_gem_object, vma_node);
1014 * When the object is being freed, after it hits 0-refcnt it
1015 * proceeds to tear down the object. In the process it will
1016 * attempt to remove the VMA offset and so acquire this
1017 * mgr->vm_lock. Therefore if we find an object with a 0-refcnt
1018 * that matches our range, we know it is in the process of being
1019 * destroyed and will be freed as soon as we release the lock -
1020 * so we have to check for the 0-refcnted object and treat it as
1023 if (!kref_get_unless_zero(&obj->refcount))
1026 drm_vma_offset_unlock_lookup(dev->vma_offset_manager);
1031 if (!drm_vma_node_is_allowed(node, priv)) {
1032 drm_gem_object_put_unlocked(obj);
1036 ret = drm_gem_mmap_obj(obj, drm_vma_node_size(node) << PAGE_SHIFT,
1039 drm_gem_object_put_unlocked(obj);
1043 EXPORT_SYMBOL(drm_gem_mmap);