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_unreference_unlocked(struct drm_gem_object
*obj
)
223 if (WARN_ON(obj
->handle_count
== 0))
227 * Must bump handle count first as this may be the last
228 * ref, in which case the object would disappear before we
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
);
237 mutex_unlock(&obj
->dev
->object_name_lock
);
239 drm_gem_object_unreference_unlocked(obj
);
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
247 * Removes the GEM handle from the @filp lookup table which has been added with
248 * drm_gem_handle_create(). If this is the last handle also cleans up linked
249 * resources like GEM names.
252 drm_gem_handle_delete(struct drm_file
*filp
, u32 handle
)
254 struct drm_device
*dev
;
255 struct drm_gem_object
*obj
;
257 /* This is gross. The idr system doesn't let us try a delete and
258 * return an error code. It just spews if you fail at deleting.
259 * So, we have to grab a lock around finding the object and then
260 * doing the delete on it and dropping the refcount, or the user
261 * could race us to double-decrement the refcount and cause a
262 * use-after-free later. Given the frequency of our handle lookups,
263 * we may want to use ida for number allocation and a hash table
264 * for the pointers, anyway.
266 spin_lock(&filp
->table_lock
);
268 /* Check if we currently have a reference on the object */
269 obj
= idr_find(&filp
->object_idr
, handle
);
271 spin_unlock(&filp
->table_lock
);
276 /* Release reference and decrement refcount. */
277 idr_remove(&filp
->object_idr
, handle
);
278 spin_unlock(&filp
->table_lock
);
280 if (drm_core_check_feature(dev
, DRIVER_PRIME
))
281 drm_gem_remove_prime_handles(obj
, filp
);
282 drm_vma_node_revoke(&obj
->vma_node
, filp
->filp
);
284 if (dev
->driver
->gem_close_object
)
285 dev
->driver
->gem_close_object(obj
, filp
);
286 drm_gem_object_handle_unreference_unlocked(obj
);
290 EXPORT_SYMBOL(drm_gem_handle_delete
);
293 * drm_gem_dumb_destroy - dumb fb callback helper for gem based drivers
294 * @file: drm file-private structure to remove the dumb handle from
295 * @dev: corresponding drm_device
296 * @handle: the dumb handle to remove
298 * This implements the ->dumb_destroy kms driver callback for drivers which use
299 * gem to manage their backing storage.
301 int drm_gem_dumb_destroy(struct drm_file
*file
,
302 struct drm_device
*dev
,
305 return drm_gem_handle_delete(file
, handle
);
307 EXPORT_SYMBOL(drm_gem_dumb_destroy
);
310 * drm_gem_handle_create_tail - internal functions to create a handle
311 * @file_priv: drm file-private structure to register the handle for
312 * @obj: object to register
313 * @handlep: pointer to return the created handle to the caller
315 * This expects the dev->object_name_lock to be held already and will drop it
316 * before returning. Used to avoid races in establishing new handles when
317 * importing an object from either an flink name or a dma-buf.
319 * Handles must be release again through drm_gem_handle_delete(). This is done
320 * when userspace closes @file_priv for all attached handles, or through the
321 * GEM_CLOSE ioctl for individual handles.
324 drm_gem_handle_create_tail(struct drm_file
*file_priv
,
325 struct drm_gem_object
*obj
,
328 struct drm_device
*dev
= obj
->dev
;
331 WARN_ON(!mutex_is_locked(&dev
->object_name_lock
));
334 * Get the user-visible handle using idr. Preload and perform
335 * allocation under our spinlock.
337 idr_preload(GFP_KERNEL
);
338 spin_lock(&file_priv
->table_lock
);
340 ret
= idr_alloc(&file_priv
->object_idr
, obj
, 1, 0, GFP_NOWAIT
);
341 drm_gem_object_reference(obj
);
343 spin_unlock(&file_priv
->table_lock
);
345 mutex_unlock(&dev
->object_name_lock
);
347 drm_gem_object_handle_unreference_unlocked(obj
);
352 ret
= drm_vma_node_allow(&obj
->vma_node
, file_priv
->filp
);
354 drm_gem_handle_delete(file_priv
, *handlep
);
358 if (dev
->driver
->gem_open_object
) {
359 ret
= dev
->driver
->gem_open_object(obj
, file_priv
);
361 drm_gem_handle_delete(file_priv
, *handlep
);
370 * drm_gem_handle_create - create a gem handle for an object
371 * @file_priv: drm file-private structure to register the handle for
372 * @obj: object to register
373 * @handlep: pionter to return the created handle to the caller
375 * Create a handle for this object. This adds a handle reference
376 * to the object, which includes a regular reference count. Callers
377 * will likely want to dereference the object afterwards.
379 int drm_gem_handle_create(struct drm_file
*file_priv
,
380 struct drm_gem_object
*obj
,
383 mutex_lock(&obj
->dev
->object_name_lock
);
385 return drm_gem_handle_create_tail(file_priv
, obj
, handlep
);
387 EXPORT_SYMBOL(drm_gem_handle_create
);
391 * drm_gem_free_mmap_offset - release a fake mmap offset for an object
392 * @obj: obj in question
394 * This routine frees fake offsets allocated by drm_gem_create_mmap_offset().
397 drm_gem_free_mmap_offset(struct drm_gem_object
*obj
)
399 struct drm_device
*dev
= obj
->dev
;
401 drm_vma_offset_remove(dev
->vma_offset_manager
, &obj
->vma_node
);
403 EXPORT_SYMBOL(drm_gem_free_mmap_offset
);
406 * drm_gem_create_mmap_offset_size - create a fake mmap offset for an object
407 * @obj: obj in question
408 * @size: the virtual size
410 * GEM memory mapping works by handing back to userspace a fake mmap offset
411 * it can use in a subsequent mmap(2) call. The DRM core code then looks
412 * up the object based on the offset and sets up the various memory mapping
415 * This routine allocates and attaches a fake offset for @obj, in cases where
416 * the virtual size differs from the physical size (ie. obj->size). Otherwise
417 * just use drm_gem_create_mmap_offset().
420 drm_gem_create_mmap_offset_size(struct drm_gem_object
*obj
, size_t size
)
422 struct drm_device
*dev
= obj
->dev
;
424 return drm_vma_offset_add(dev
->vma_offset_manager
, &obj
->vma_node
,
427 EXPORT_SYMBOL(drm_gem_create_mmap_offset_size
);
430 * drm_gem_create_mmap_offset - create a fake mmap offset for an object
431 * @obj: obj in question
433 * GEM memory mapping works by handing back to userspace a fake mmap offset
434 * it can use in a subsequent mmap(2) call. The DRM core code then looks
435 * up the object based on the offset and sets up the various memory mapping
438 * This routine allocates and attaches a fake offset for @obj.
440 int drm_gem_create_mmap_offset(struct drm_gem_object
*obj
)
442 return drm_gem_create_mmap_offset_size(obj
, obj
->size
);
444 EXPORT_SYMBOL(drm_gem_create_mmap_offset
);
447 * drm_gem_get_pages - helper to allocate backing pages for a GEM object
449 * @obj: obj in question
451 * This reads the page-array of the shmem-backing storage of the given gem
452 * object. An array of pages is returned. If a page is not allocated or
453 * swapped-out, this will allocate/swap-in the required pages. Note that the
454 * whole object is covered by the page-array and pinned in memory.
456 * Use drm_gem_put_pages() to release the array and unpin all pages.
458 * This uses the GFP-mask set on the shmem-mapping (see mapping_set_gfp_mask()).
459 * If you require other GFP-masks, you have to do those allocations yourself.
461 * Note that you are not allowed to change gfp-zones during runtime. That is,
462 * shmem_read_mapping_page_gfp() must be called with the same gfp_zone(gfp) as
463 * set during initialization. If you have special zone constraints, set them
464 * after drm_gem_init_object() via mapping_set_gfp_mask(). shmem-core takes care
465 * to keep pages in the required zone during swap-in.
467 struct page
**drm_gem_get_pages(struct drm_gem_object
*obj
)
469 struct address_space
*mapping
;
470 struct page
*p
, **pages
;
473 /* This is the shared memory object that backs the GEM resource */
474 mapping
= file_inode(obj
->filp
)->i_mapping
;
476 /* We already BUG_ON() for non-page-aligned sizes in
477 * drm_gem_object_init(), so we should never hit this unless
478 * driver author is doing something really wrong:
480 WARN_ON((obj
->size
& (PAGE_SIZE
- 1)) != 0);
482 npages
= obj
->size
>> PAGE_SHIFT
;
484 pages
= drm_malloc_ab(npages
, sizeof(struct page
*));
486 return ERR_PTR(-ENOMEM
);
488 for (i
= 0; i
< npages
; i
++) {
489 p
= shmem_read_mapping_page(mapping
, i
);
494 /* Make sure shmem keeps __GFP_DMA32 allocated pages in the
495 * correct region during swapin. Note that this requires
496 * __GFP_DMA32 to be set in mapping_gfp_mask(inode->i_mapping)
497 * so shmem can relocate pages during swapin if required.
499 BUG_ON(mapping_gfp_constraint(mapping
, __GFP_DMA32
) &&
500 (page_to_pfn(p
) >= 0x00100000UL
));
507 page_cache_release(pages
[i
]);
509 drm_free_large(pages
);
512 EXPORT_SYMBOL(drm_gem_get_pages
);
515 * drm_gem_put_pages - helper to free backing pages for a GEM object
516 * @obj: obj in question
517 * @pages: pages to free
518 * @dirty: if true, pages will be marked as dirty
519 * @accessed: if true, the pages will be marked as accessed
521 void drm_gem_put_pages(struct drm_gem_object
*obj
, struct page
**pages
,
522 bool dirty
, bool accessed
)
526 /* We already BUG_ON() for non-page-aligned sizes in
527 * drm_gem_object_init(), so we should never hit this unless
528 * driver author is doing something really wrong:
530 WARN_ON((obj
->size
& (PAGE_SIZE
- 1)) != 0);
532 npages
= obj
->size
>> PAGE_SHIFT
;
534 for (i
= 0; i
< npages
; i
++) {
536 set_page_dirty(pages
[i
]);
539 mark_page_accessed(pages
[i
]);
541 /* Undo the reference we took when populating the table */
542 page_cache_release(pages
[i
]);
545 drm_free_large(pages
);
547 EXPORT_SYMBOL(drm_gem_put_pages
);
550 * drm_gem_object_lookup - look up a GEM object from it's handle
552 * @filp: DRM file private date
553 * @handle: userspace handle
557 * A reference to the object named by the handle if such exists on @filp, NULL
560 struct drm_gem_object
*
561 drm_gem_object_lookup(struct drm_device
*dev
, struct drm_file
*filp
,
564 struct drm_gem_object
*obj
;
566 spin_lock(&filp
->table_lock
);
568 /* Check if we currently have a reference on the object */
569 obj
= idr_find(&filp
->object_idr
, handle
);
571 spin_unlock(&filp
->table_lock
);
575 drm_gem_object_reference(obj
);
577 spin_unlock(&filp
->table_lock
);
581 EXPORT_SYMBOL(drm_gem_object_lookup
);
584 * drm_gem_close_ioctl - implementation of the GEM_CLOSE ioctl
587 * @file_priv: drm file-private structure
589 * Releases the handle to an mm object.
592 drm_gem_close_ioctl(struct drm_device
*dev
, void *data
,
593 struct drm_file
*file_priv
)
595 struct drm_gem_close
*args
= data
;
598 if (!drm_core_check_feature(dev
, DRIVER_GEM
))
601 ret
= drm_gem_handle_delete(file_priv
, args
->handle
);
607 * drm_gem_flink_ioctl - implementation of the GEM_FLINK ioctl
610 * @file_priv: drm file-private structure
612 * Create a global name for an object, returning the name.
614 * Note that the name does not hold a reference; when the object
615 * is freed, the name goes away.
618 drm_gem_flink_ioctl(struct drm_device
*dev
, void *data
,
619 struct drm_file
*file_priv
)
621 struct drm_gem_flink
*args
= data
;
622 struct drm_gem_object
*obj
;
625 if (!drm_core_check_feature(dev
, DRIVER_GEM
))
628 obj
= drm_gem_object_lookup(dev
, file_priv
, args
->handle
);
632 mutex_lock(&dev
->object_name_lock
);
633 idr_preload(GFP_KERNEL
);
634 /* prevent races with concurrent gem_close. */
635 if (obj
->handle_count
== 0) {
641 ret
= idr_alloc(&dev
->object_name_idr
, obj
, 1, 0, GFP_NOWAIT
);
648 args
->name
= (uint64_t) obj
->name
;
653 mutex_unlock(&dev
->object_name_lock
);
654 drm_gem_object_unreference_unlocked(obj
);
659 * drm_gem_open - implementation of the GEM_OPEN ioctl
662 * @file_priv: drm file-private structure
664 * Open an object using the global name, returning a handle and the size.
666 * This handle (of course) holds a reference to the object, so the object
667 * will not go away until the handle is deleted.
670 drm_gem_open_ioctl(struct drm_device
*dev
, void *data
,
671 struct drm_file
*file_priv
)
673 struct drm_gem_open
*args
= data
;
674 struct drm_gem_object
*obj
;
678 if (!drm_core_check_feature(dev
, DRIVER_GEM
))
681 mutex_lock(&dev
->object_name_lock
);
682 obj
= idr_find(&dev
->object_name_idr
, (int) args
->name
);
684 drm_gem_object_reference(obj
);
686 mutex_unlock(&dev
->object_name_lock
);
690 /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */
691 ret
= drm_gem_handle_create_tail(file_priv
, obj
, &handle
);
692 drm_gem_object_unreference_unlocked(obj
);
696 args
->handle
= handle
;
697 args
->size
= obj
->size
;
703 * gem_gem_open - initalizes GEM file-private structures at devnode open time
704 * @dev: drm_device which is being opened by userspace
705 * @file_private: drm file-private structure to set up
707 * Called at device open time, sets up the structure for handling refcounting
711 drm_gem_open(struct drm_device
*dev
, struct drm_file
*file_private
)
713 idr_init(&file_private
->object_idr
);
714 spin_lock_init(&file_private
->table_lock
);
718 * Called at device close to release the file's
719 * handle references on objects.
722 drm_gem_object_release_handle(int id
, void *ptr
, void *data
)
724 struct drm_file
*file_priv
= data
;
725 struct drm_gem_object
*obj
= ptr
;
726 struct drm_device
*dev
= obj
->dev
;
728 if (drm_core_check_feature(dev
, DRIVER_PRIME
))
729 drm_gem_remove_prime_handles(obj
, file_priv
);
730 drm_vma_node_revoke(&obj
->vma_node
, file_priv
->filp
);
732 if (dev
->driver
->gem_close_object
)
733 dev
->driver
->gem_close_object(obj
, file_priv
);
735 drm_gem_object_handle_unreference_unlocked(obj
);
741 * drm_gem_release - release file-private GEM resources
742 * @dev: drm_device which is being closed by userspace
743 * @file_private: drm file-private structure to clean up
745 * Called at close time when the filp is going away.
747 * Releases any remaining references on objects by this filp.
750 drm_gem_release(struct drm_device
*dev
, struct drm_file
*file_private
)
752 idr_for_each(&file_private
->object_idr
,
753 &drm_gem_object_release_handle
, file_private
);
754 idr_destroy(&file_private
->object_idr
);
758 drm_gem_object_release(struct drm_gem_object
*obj
)
760 WARN_ON(obj
->dma_buf
);
765 drm_gem_free_mmap_offset(obj
);
767 EXPORT_SYMBOL(drm_gem_object_release
);
770 * drm_gem_object_free - free a GEM object
771 * @kref: kref of the object to free
773 * Called after the last reference to the object has been lost.
774 * Must be called holding struct_ mutex
779 drm_gem_object_free(struct kref
*kref
)
781 struct drm_gem_object
*obj
=
782 container_of(kref
, struct drm_gem_object
, refcount
);
783 struct drm_device
*dev
= obj
->dev
;
785 WARN_ON(!mutex_is_locked(&dev
->struct_mutex
));
787 if (dev
->driver
->gem_free_object
!= NULL
)
788 dev
->driver
->gem_free_object(obj
);
790 EXPORT_SYMBOL(drm_gem_object_free
);
793 * drm_gem_vm_open - vma->ops->open implementation for GEM
794 * @vma: VM area structure
796 * This function implements the #vm_operations_struct open() callback for GEM
797 * drivers. This must be used together with drm_gem_vm_close().
799 void drm_gem_vm_open(struct vm_area_struct
*vma
)
801 struct drm_gem_object
*obj
= vma
->vm_private_data
;
803 drm_gem_object_reference(obj
);
805 EXPORT_SYMBOL(drm_gem_vm_open
);
808 * drm_gem_vm_close - vma->ops->close implementation for GEM
809 * @vma: VM area structure
811 * This function implements the #vm_operations_struct close() callback for GEM
812 * drivers. This must be used together with drm_gem_vm_open().
814 void drm_gem_vm_close(struct vm_area_struct
*vma
)
816 struct drm_gem_object
*obj
= vma
->vm_private_data
;
818 drm_gem_object_unreference_unlocked(obj
);
820 EXPORT_SYMBOL(drm_gem_vm_close
);
823 * drm_gem_mmap_obj - memory map a GEM object
824 * @obj: the GEM object to map
825 * @obj_size: the object size to be mapped, in bytes
826 * @vma: VMA for the area to be mapped
828 * Set up the VMA to prepare mapping of the GEM object using the gem_vm_ops
829 * provided by the driver. Depending on their requirements, drivers can either
830 * provide a fault handler in their gem_vm_ops (in which case any accesses to
831 * the object will be trapped, to perform migration, GTT binding, surface
832 * register allocation, or performance monitoring), or mmap the buffer memory
833 * synchronously after calling drm_gem_mmap_obj.
835 * This function is mainly intended to implement the DMABUF mmap operation, when
836 * the GEM object is not looked up based on its fake offset. To implement the
837 * DRM mmap operation, drivers should use the drm_gem_mmap() function.
839 * drm_gem_mmap_obj() assumes the user is granted access to the buffer while
840 * drm_gem_mmap() prevents unprivileged users from mapping random objects. So
841 * callers must verify access restrictions before calling this helper.
843 * Return 0 or success or -EINVAL if the object size is smaller than the VMA
844 * size, or if no gem_vm_ops are provided.
846 int drm_gem_mmap_obj(struct drm_gem_object
*obj
, unsigned long obj_size
,
847 struct vm_area_struct
*vma
)
849 struct drm_device
*dev
= obj
->dev
;
851 /* Check for valid size. */
852 if (obj_size
< vma
->vm_end
- vma
->vm_start
)
855 if (!dev
->driver
->gem_vm_ops
)
858 vma
->vm_flags
|= VM_IO
| VM_PFNMAP
| VM_DONTEXPAND
| VM_DONTDUMP
;
859 vma
->vm_ops
= dev
->driver
->gem_vm_ops
;
860 vma
->vm_private_data
= obj
;
861 vma
->vm_page_prot
= pgprot_writecombine(vm_get_page_prot(vma
->vm_flags
));
863 /* Take a ref for this mapping of the object, so that the fault
864 * handler can dereference the mmap offset's pointer to the object.
865 * This reference is cleaned up by the corresponding vm_close
866 * (which should happen whether the vma was created by this call, or
867 * by a vm_open due to mremap or partial unmap or whatever).
869 drm_gem_object_reference(obj
);
873 EXPORT_SYMBOL(drm_gem_mmap_obj
);
876 * drm_gem_mmap - memory map routine for GEM objects
877 * @filp: DRM file pointer
878 * @vma: VMA for the area to be mapped
880 * If a driver supports GEM object mapping, mmap calls on the DRM file
881 * descriptor will end up here.
883 * Look up the GEM object based on the offset passed in (vma->vm_pgoff will
884 * contain the fake offset we created when the GTT map ioctl was called on
885 * the object) and map it with a call to drm_gem_mmap_obj().
887 * If the caller is not granted access to the buffer object, the mmap will fail
888 * with EACCES. Please see the vma manager for more information.
890 int drm_gem_mmap(struct file
*filp
, struct vm_area_struct
*vma
)
892 struct drm_file
*priv
= filp
->private_data
;
893 struct drm_device
*dev
= priv
->minor
->dev
;
894 struct drm_gem_object
*obj
= NULL
;
895 struct drm_vma_offset_node
*node
;
898 if (drm_device_is_unplugged(dev
))
901 drm_vma_offset_lock_lookup(dev
->vma_offset_manager
);
902 node
= drm_vma_offset_exact_lookup_locked(dev
->vma_offset_manager
,
906 obj
= container_of(node
, struct drm_gem_object
, vma_node
);
908 * When the object is being freed, after it hits 0-refcnt it
909 * proceeds to tear down the object. In the process it will
910 * attempt to remove the VMA offset and so acquire this
911 * mgr->vm_lock. Therefore if we find an object with a 0-refcnt
912 * that matches our range, we know it is in the process of being
913 * destroyed and will be freed as soon as we release the lock -
914 * so we have to check for the 0-refcnted object and treat it as
917 if (!kref_get_unless_zero(&obj
->refcount
))
920 drm_vma_offset_unlock_lookup(dev
->vma_offset_manager
);
925 if (!drm_vma_node_is_allowed(node
, filp
)) {
926 drm_gem_object_unreference_unlocked(obj
);
930 ret
= drm_gem_mmap_obj(obj
, drm_vma_node_size(node
) << PAGE_SHIFT
,
933 drm_gem_object_unreference_unlocked(obj
);
937 EXPORT_SYMBOL(drm_gem_mmap
);