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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 * drm_gem_init - Initialize the GEM device fields
89 * @dev: drm_devic structure to initialize
90 */
91int
92drm_gem_init(struct drm_device *dev)
93{
94 struct drm_vma_offset_manager *vma_offset_manager;
95
96 mutex_init(&dev->object_name_lock);
97 idr_init(&dev->object_name_idr);
98
99 vma_offset_manager = kzalloc(sizeof(*vma_offset_manager), GFP_KERNEL);
100 if (!vma_offset_manager) {
101 DRM_ERROR("out of memory\n");
102 return -ENOMEM;
103 }
104
105 dev->vma_offset_manager = vma_offset_manager;
106 drm_vma_offset_manager_init(vma_offset_manager,
107 DRM_FILE_PAGE_OFFSET_START,
108 DRM_FILE_PAGE_OFFSET_SIZE);
109
110 return 0;
111}
112
113void
114drm_gem_destroy(struct drm_device *dev)
115{
116
117 drm_vma_offset_manager_destroy(dev->vma_offset_manager);
118 kfree(dev->vma_offset_manager);
119 dev->vma_offset_manager = NULL;
120}
121
122/**
123 * drm_gem_object_init - initialize an allocated shmem-backed GEM object
124 * @dev: drm_device the object should be initialized for
125 * @obj: drm_gem_object to initialize
126 * @size: object size
127 *
128 * Initialize an already allocated GEM object of the specified size with
129 * shmfs backing store.
130 */
131int drm_gem_object_init(struct drm_device *dev,
132 struct drm_gem_object *obj, size_t size)
133{
134 struct file *filp;
135
136 drm_gem_private_object_init(dev, obj, size);
137
138 filp = shmem_file_setup("drm mm object", size, VM_NORESERVE);
139 if (IS_ERR(filp))
140 return PTR_ERR(filp);
141
142 obj->filp = filp;
143
144 return 0;
145}
146EXPORT_SYMBOL(drm_gem_object_init);
147
148/**
149 * drm_gem_object_init - initialize an allocated private GEM object
150 * @dev: drm_device the object should be initialized for
151 * @obj: drm_gem_object to initialize
152 * @size: object size
153 *
154 * Initialize an already allocated GEM object of the specified size with
155 * no GEM provided backing store. Instead the caller is responsible for
156 * backing the object and handling it.
157 */
158void drm_gem_private_object_init(struct drm_device *dev,
159 struct drm_gem_object *obj, size_t size)
160{
161 BUG_ON((size & (PAGE_SIZE - 1)) != 0);
162
163 obj->dev = dev;
164 obj->filp = NULL;
165
166 kref_init(&obj->refcount);
167 obj->handle_count = 0;
168 obj->size = size;
169 drm_vma_node_reset(&obj->vma_node);
170}
171EXPORT_SYMBOL(drm_gem_private_object_init);
172
173static void
174drm_gem_remove_prime_handles(struct drm_gem_object *obj, struct drm_file *filp)
175{
176 /*
177 * Note: obj->dma_buf can't disappear as long as we still hold a
178 * handle reference in obj->handle_count.
179 */
180 mutex_lock(&filp->prime.lock);
181 if (obj->dma_buf) {
182 drm_prime_remove_buf_handle_locked(&filp->prime,
183 obj->dma_buf);
184 }
185 mutex_unlock(&filp->prime.lock);
186}
187
188/**
189 * drm_gem_object_free - release resources bound to userspace handles
190 * @obj: GEM object to clean up.
191 *
192 * Called after the last handle to the object has been closed
193 *
194 * Removes any name for the object. Note that this must be
195 * called before drm_gem_object_free or we'll be touching
196 * freed memory
197 */
198static void drm_gem_object_handle_free(struct drm_gem_object *obj)
199{
200 struct drm_device *dev = obj->dev;
201
202 /* Remove any name for this object */
203 if (obj->name) {
204 idr_remove(&dev->object_name_idr, obj->name);
205 obj->name = 0;
206 }
207}
208
209static void drm_gem_object_exported_dma_buf_free(struct drm_gem_object *obj)
210{
211 /* Unbreak the reference cycle if we have an exported dma_buf. */
212 if (obj->dma_buf) {
213 dma_buf_put(obj->dma_buf);
214 obj->dma_buf = NULL;
215 }
216}
217
218static void
219drm_gem_object_handle_unreference_unlocked(struct drm_gem_object *obj)
220{
221 if (WARN_ON(obj->handle_count == 0))
222 return;
223
224 /*
225 * Must bump handle count first as this may be the last
226 * ref, in which case the object would disappear before we
227 * checked for a name
228 */
229
230 mutex_lock(&obj->dev->object_name_lock);
231 if (--obj->handle_count == 0) {
232 drm_gem_object_handle_free(obj);
233 drm_gem_object_exported_dma_buf_free(obj);
234 }
235 mutex_unlock(&obj->dev->object_name_lock);
236
237 drm_gem_object_unreference_unlocked(obj);
238}
239
240/**
241 * drm_gem_handle_delete - deletes the given file-private handle
242 * @filp: drm file-private structure to use for the handle look up
243 * @handle: userspace handle to delete
244 *
245 * Removes the GEM handle from the @filp lookup table and if this is the last
246 * handle also cleans up linked resources like GEM names.
247 */
248int
249drm_gem_handle_delete(struct drm_file *filp, u32 handle)
250{
251 struct drm_device *dev;
252 struct drm_gem_object *obj;
253
254 /* This is gross. The idr system doesn't let us try a delete and
255 * return an error code. It just spews if you fail at deleting.
256 * So, we have to grab a lock around finding the object and then
257 * doing the delete on it and dropping the refcount, or the user
258 * could race us to double-decrement the refcount and cause a
259 * use-after-free later. Given the frequency of our handle lookups,
260 * we may want to use ida for number allocation and a hash table
261 * for the pointers, anyway.
262 */
263 spin_lock(&filp->table_lock);
264
265 /* Check if we currently have a reference on the object */
266 obj = idr_find(&filp->object_idr, handle);
267 if (obj == NULL) {
268 spin_unlock(&filp->table_lock);
269 return -EINVAL;
270 }
271 dev = obj->dev;
272
273 /* Release reference and decrement refcount. */
274 idr_remove(&filp->object_idr, handle);
275 spin_unlock(&filp->table_lock);
276
277 if (drm_core_check_feature(dev, DRIVER_PRIME))
278 drm_gem_remove_prime_handles(obj, filp);
279 drm_vma_node_revoke(&obj->vma_node, filp->filp);
280
281 if (dev->driver->gem_close_object)
282 dev->driver->gem_close_object(obj, filp);
283 drm_gem_object_handle_unreference_unlocked(obj);
284
285 return 0;
286}
287EXPORT_SYMBOL(drm_gem_handle_delete);
288
289/**
290 * drm_gem_dumb_destroy - dumb fb callback helper for gem based drivers
291 * @file: drm file-private structure to remove the dumb handle from
292 * @dev: corresponding drm_device
293 * @handle: the dumb handle to remove
294 *
295 * This implements the ->dumb_destroy kms driver callback for drivers which use
296 * gem to manage their backing storage.
297 */
298int drm_gem_dumb_destroy(struct drm_file *file,
299 struct drm_device *dev,
300 uint32_t handle)
301{
302 return drm_gem_handle_delete(file, handle);
303}
304EXPORT_SYMBOL(drm_gem_dumb_destroy);
305
306/**
307 * drm_gem_handle_create_tail - internal functions to create a handle
308 * @file_priv: drm file-private structure to register the handle for
309 * @obj: object to register
310 * @handlep: pionter to return the created handle to the caller
311 *
312 * This expects the dev->object_name_lock to be held already and will drop it
313 * before returning. Used to avoid races in establishing new handles when
314 * importing an object from either an flink name or a dma-buf.
315 */
316int
317drm_gem_handle_create_tail(struct drm_file *file_priv,
318 struct drm_gem_object *obj,
319 u32 *handlep)
320{
321 struct drm_device *dev = obj->dev;
322 int ret;
323
324 WARN_ON(!mutex_is_locked(&dev->object_name_lock));
325
326 /*
327 * Get the user-visible handle using idr. Preload and perform
328 * allocation under our spinlock.
329 */
330 idr_preload(GFP_KERNEL);
331 spin_lock(&file_priv->table_lock);
332
333 ret = idr_alloc(&file_priv->object_idr, obj, 1, 0, GFP_NOWAIT);
334 drm_gem_object_reference(obj);
335 obj->handle_count++;
336 spin_unlock(&file_priv->table_lock);
337 idr_preload_end();
338 mutex_unlock(&dev->object_name_lock);
339 if (ret < 0) {
340 drm_gem_object_handle_unreference_unlocked(obj);
341 return ret;
342 }
343 *handlep = ret;
344
345 ret = drm_vma_node_allow(&obj->vma_node, file_priv->filp);
346 if (ret) {
347 drm_gem_handle_delete(file_priv, *handlep);
348 return ret;
349 }
350
351 if (dev->driver->gem_open_object) {
352 ret = dev->driver->gem_open_object(obj, file_priv);
353 if (ret) {
354 drm_gem_handle_delete(file_priv, *handlep);
355 return ret;
356 }
357 }
358
359 return 0;
360}
361
362/**
363 * gem_handle_create - create a gem handle for an object
364 * @file_priv: drm file-private structure to register the handle for
365 * @obj: object to register
366 * @handlep: pionter to return the created handle to the caller
367 *
368 * Create a handle for this object. This adds a handle reference
369 * to the object, which includes a regular reference count. Callers
370 * will likely want to dereference the object afterwards.
371 */
372int
373drm_gem_handle_create(struct drm_file *file_priv,
374 struct drm_gem_object *obj,
375 u32 *handlep)
376{
377 mutex_lock(&obj->dev->object_name_lock);
378
379 return drm_gem_handle_create_tail(file_priv, obj, handlep);
380}
381EXPORT_SYMBOL(drm_gem_handle_create);
382
383
384/**
385 * drm_gem_free_mmap_offset - release a fake mmap offset for an object
386 * @obj: obj in question
387 *
388 * This routine frees fake offsets allocated by drm_gem_create_mmap_offset().
389 */
390void
391drm_gem_free_mmap_offset(struct drm_gem_object *obj)
392{
393 struct drm_device *dev = obj->dev;
394
395 drm_vma_offset_remove(dev->vma_offset_manager, &obj->vma_node);
396}
397EXPORT_SYMBOL(drm_gem_free_mmap_offset);
398
399/**
400 * drm_gem_create_mmap_offset_size - create a fake mmap offset for an object
401 * @obj: obj in question
402 * @size: the virtual size
403 *
404 * GEM memory mapping works by handing back to userspace a fake mmap offset
405 * it can use in a subsequent mmap(2) call. The DRM core code then looks
406 * up the object based on the offset and sets up the various memory mapping
407 * structures.
408 *
409 * This routine allocates and attaches a fake offset for @obj, in cases where
410 * the virtual size differs from the physical size (ie. obj->size). Otherwise
411 * just use drm_gem_create_mmap_offset().
412 */
413int
414drm_gem_create_mmap_offset_size(struct drm_gem_object *obj, size_t size)
415{
416 struct drm_device *dev = obj->dev;
417
418 return drm_vma_offset_add(dev->vma_offset_manager, &obj->vma_node,
419 size / PAGE_SIZE);
420}
421EXPORT_SYMBOL(drm_gem_create_mmap_offset_size);
422
423/**
424 * drm_gem_create_mmap_offset - create a fake mmap offset for an object
425 * @obj: obj in question
426 *
427 * GEM memory mapping works by handing back to userspace a fake mmap offset
428 * it can use in a subsequent mmap(2) call. The DRM core code then looks
429 * up the object based on the offset and sets up the various memory mapping
430 * structures.
431 *
432 * This routine allocates and attaches a fake offset for @obj.
433 */
434int drm_gem_create_mmap_offset(struct drm_gem_object *obj)
435{
436 return drm_gem_create_mmap_offset_size(obj, obj->size);
437}
438EXPORT_SYMBOL(drm_gem_create_mmap_offset);
439
440/**
441 * drm_gem_get_pages - helper to allocate backing pages for a GEM object
442 * from shmem
443 * @obj: obj in question
444 * @gfpmask: gfp mask of requested pages
445 */
446struct page **drm_gem_get_pages(struct drm_gem_object *obj, gfp_t gfpmask)
447{
448 struct inode *inode;
449 struct address_space *mapping;
450 struct page *p, **pages;
451 int i, npages;
452
453 /* This is the shared memory object that backs the GEM resource */
454 inode = file_inode(obj->filp);
455 mapping = inode->i_mapping;
456
457 /* We already BUG_ON() for non-page-aligned sizes in
458 * drm_gem_object_init(), so we should never hit this unless
459 * driver author is doing something really wrong:
460 */
461 WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0);
462
463 npages = obj->size >> PAGE_SHIFT;
464
465 pages = drm_malloc_ab(npages, sizeof(struct page *));
466 if (pages == NULL)
467 return ERR_PTR(-ENOMEM);
468
469 gfpmask |= mapping_gfp_mask(mapping);
470
471 for (i = 0; i < npages; i++) {
472 p = shmem_read_mapping_page_gfp(mapping, i, gfpmask);
473 if (IS_ERR(p))
474 goto fail;
475 pages[i] = p;
476
477 /* There is a hypothetical issue w/ drivers that require
478 * buffer memory in the low 4GB.. if the pages are un-
479 * pinned, and swapped out, they can end up swapped back
480 * in above 4GB. If pages are already in memory, then
481 * shmem_read_mapping_page_gfp will ignore the gfpmask,
482 * even if the already in-memory page disobeys the mask.
483 *
484 * It is only a theoretical issue today, because none of
485 * the devices with this limitation can be populated with
486 * enough memory to trigger the issue. But this BUG_ON()
487 * is here as a reminder in case the problem with
488 * shmem_read_mapping_page_gfp() isn't solved by the time
489 * it does become a real issue.
490 *
491 * See this thread: http://lkml.org/lkml/2011/7/11/238
492 */
493 BUG_ON((gfpmask & __GFP_DMA32) &&
494 (page_to_pfn(p) >= 0x00100000UL));
495 }
496
497 return pages;
498
499fail:
500 while (i--)
501 page_cache_release(pages[i]);
502
503 drm_free_large(pages);
504 return ERR_CAST(p);
505}
506EXPORT_SYMBOL(drm_gem_get_pages);
507
508/**
509 * drm_gem_put_pages - helper to free backing pages for a GEM object
510 * @obj: obj in question
511 * @pages: pages to free
512 * @dirty: if true, pages will be marked as dirty
513 * @accessed: if true, the pages will be marked as accessed
514 */
515void drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages,
516 bool dirty, bool accessed)
517{
518 int i, npages;
519
520 /* We already BUG_ON() for non-page-aligned sizes in
521 * drm_gem_object_init(), so we should never hit this unless
522 * driver author is doing something really wrong:
523 */
524 WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0);
525
526 npages = obj->size >> PAGE_SHIFT;
527
528 for (i = 0; i < npages; i++) {
529 if (dirty)
530 set_page_dirty(pages[i]);
531
532 if (accessed)
533 mark_page_accessed(pages[i]);
534
535 /* Undo the reference we took when populating the table */
536 page_cache_release(pages[i]);
537 }
538
539 drm_free_large(pages);
540}
541EXPORT_SYMBOL(drm_gem_put_pages);
542
543/** Returns a reference to the object named by the handle. */
544struct drm_gem_object *
545drm_gem_object_lookup(struct drm_device *dev, struct drm_file *filp,
546 u32 handle)
547{
548 struct drm_gem_object *obj;
549
550 spin_lock(&filp->table_lock);
551
552 /* Check if we currently have a reference on the object */
553 obj = idr_find(&filp->object_idr, handle);
554 if (obj == NULL) {
555 spin_unlock(&filp->table_lock);
556 return NULL;
557 }
558
559 drm_gem_object_reference(obj);
560
561 spin_unlock(&filp->table_lock);
562
563 return obj;
564}
565EXPORT_SYMBOL(drm_gem_object_lookup);
566
567/**
568 * drm_gem_close_ioctl - implementation of the GEM_CLOSE ioctl
569 * @dev: drm_device
570 * @data: ioctl data
571 * @file_priv: drm file-private structure
572 *
573 * Releases the handle to an mm object.
574 */
575int
576drm_gem_close_ioctl(struct drm_device *dev, void *data,
577 struct drm_file *file_priv)
578{
579 struct drm_gem_close *args = data;
580 int ret;
581
582 if (!(dev->driver->driver_features & DRIVER_GEM))
583 return -ENODEV;
584
585 ret = drm_gem_handle_delete(file_priv, args->handle);
586
587 return ret;
588}
589
590/**
591 * drm_gem_flink_ioctl - implementation of the GEM_FLINK ioctl
592 * @dev: drm_device
593 * @data: ioctl data
594 * @file_priv: drm file-private structure
595 *
596 * Create a global name for an object, returning the name.
597 *
598 * Note that the name does not hold a reference; when the object
599 * is freed, the name goes away.
600 */
601int
602drm_gem_flink_ioctl(struct drm_device *dev, void *data,
603 struct drm_file *file_priv)
604{
605 struct drm_gem_flink *args = data;
606 struct drm_gem_object *obj;
607 int ret;
608
609 if (!(dev->driver->driver_features & DRIVER_GEM))
610 return -ENODEV;
611
612 obj = drm_gem_object_lookup(dev, file_priv, args->handle);
613 if (obj == NULL)
614 return -ENOENT;
615
616 mutex_lock(&dev->object_name_lock);
617 idr_preload(GFP_KERNEL);
618 /* prevent races with concurrent gem_close. */
619 if (obj->handle_count == 0) {
620 ret = -ENOENT;
621 goto err;
622 }
623
624 if (!obj->name) {
625 ret = idr_alloc(&dev->object_name_idr, obj, 1, 0, GFP_NOWAIT);
626 if (ret < 0)
627 goto err;
628
629 obj->name = ret;
630 }
631
632 args->name = (uint64_t) obj->name;
633 ret = 0;
634
635err:
636 idr_preload_end();
637 mutex_unlock(&dev->object_name_lock);
638 drm_gem_object_unreference_unlocked(obj);
639 return ret;
640}
641
642/**
643 * drm_gem_open - implementation of the GEM_OPEN ioctl
644 * @dev: drm_device
645 * @data: ioctl data
646 * @file_priv: drm file-private structure
647 *
648 * Open an object using the global name, returning a handle and the size.
649 *
650 * This handle (of course) holds a reference to the object, so the object
651 * will not go away until the handle is deleted.
652 */
653int
654drm_gem_open_ioctl(struct drm_device *dev, void *data,
655 struct drm_file *file_priv)
656{
657 struct drm_gem_open *args = data;
658 struct drm_gem_object *obj;
659 int ret;
660 u32 handle;
661
662 if (!(dev->driver->driver_features & DRIVER_GEM))
663 return -ENODEV;
664
665 mutex_lock(&dev->object_name_lock);
666 obj = idr_find(&dev->object_name_idr, (int) args->name);
667 if (obj) {
668 drm_gem_object_reference(obj);
669 } else {
670 mutex_unlock(&dev->object_name_lock);
671 return -ENOENT;
672 }
673
674 /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */
675 ret = drm_gem_handle_create_tail(file_priv, obj, &handle);
676 drm_gem_object_unreference_unlocked(obj);
677 if (ret)
678 return ret;
679
680 args->handle = handle;
681 args->size = obj->size;
682
683 return 0;
684}
685
686/**
687 * gem_gem_open - initalizes GEM file-private structures at devnode open time
688 * @dev: drm_device which is being opened by userspace
689 * @file_private: drm file-private structure to set up
690 *
691 * Called at device open time, sets up the structure for handling refcounting
692 * of mm objects.
693 */
694void
695drm_gem_open(struct drm_device *dev, struct drm_file *file_private)
696{
697 idr_init(&file_private->object_idr);
698 spin_lock_init(&file_private->table_lock);
699}
700
701/*
702 * Called at device close to release the file's
703 * handle references on objects.
704 */
705static int
706drm_gem_object_release_handle(int id, void *ptr, void *data)
707{
708 struct drm_file *file_priv = data;
709 struct drm_gem_object *obj = ptr;
710 struct drm_device *dev = obj->dev;
711
712 if (drm_core_check_feature(dev, DRIVER_PRIME))
713 drm_gem_remove_prime_handles(obj, file_priv);
714 drm_vma_node_revoke(&obj->vma_node, file_priv->filp);
715
716 if (dev->driver->gem_close_object)
717 dev->driver->gem_close_object(obj, file_priv);
718
719 drm_gem_object_handle_unreference_unlocked(obj);
720
721 return 0;
722}
723
724/**
725 * drm_gem_release - release file-private GEM resources
726 * @dev: drm_device which is being closed by userspace
727 * @file_private: drm file-private structure to clean up
728 *
729 * Called at close time when the filp is going away.
730 *
731 * Releases any remaining references on objects by this filp.
732 */
733void
734drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
735{
736 idr_for_each(&file_private->object_idr,
737 &drm_gem_object_release_handle, file_private);
738 idr_destroy(&file_private->object_idr);
739}
740
741void
742drm_gem_object_release(struct drm_gem_object *obj)
743{
744 WARN_ON(obj->dma_buf);
745
746 if (obj->filp)
747 fput(obj->filp);
748
749 drm_gem_free_mmap_offset(obj);
750}
751EXPORT_SYMBOL(drm_gem_object_release);
752
753/**
754 * drm_gem_object_free - free a GEM object
755 * @kref: kref of the object to free
756 *
757 * Called after the last reference to the object has been lost.
758 * Must be called holding struct_ mutex
759 *
760 * Frees the object
761 */
762void
763drm_gem_object_free(struct kref *kref)
764{
765 struct drm_gem_object *obj = (struct drm_gem_object *) kref;
766 struct drm_device *dev = obj->dev;
767
768 BUG_ON(!mutex_is_locked(&dev->struct_mutex));
769
770 if (dev->driver->gem_free_object != NULL)
771 dev->driver->gem_free_object(obj);
772}
773EXPORT_SYMBOL(drm_gem_object_free);
774
775void drm_gem_vm_open(struct vm_area_struct *vma)
776{
777 struct drm_gem_object *obj = vma->vm_private_data;
778
779 drm_gem_object_reference(obj);
780
781 mutex_lock(&obj->dev->struct_mutex);
782 drm_vm_open_locked(obj->dev, vma);
783 mutex_unlock(&obj->dev->struct_mutex);
784}
785EXPORT_SYMBOL(drm_gem_vm_open);
786
787void drm_gem_vm_close(struct vm_area_struct *vma)
788{
789 struct drm_gem_object *obj = vma->vm_private_data;
790 struct drm_device *dev = obj->dev;
791
792 mutex_lock(&dev->struct_mutex);
793 drm_vm_close_locked(obj->dev, vma);
794 drm_gem_object_unreference(obj);
795 mutex_unlock(&dev->struct_mutex);
796}
797EXPORT_SYMBOL(drm_gem_vm_close);
798
799/**
800 * drm_gem_mmap_obj - memory map a GEM object
801 * @obj: the GEM object to map
802 * @obj_size: the object size to be mapped, in bytes
803 * @vma: VMA for the area to be mapped
804 *
805 * Set up the VMA to prepare mapping of the GEM object using the gem_vm_ops
806 * provided by the driver. Depending on their requirements, drivers can either
807 * provide a fault handler in their gem_vm_ops (in which case any accesses to
808 * the object will be trapped, to perform migration, GTT binding, surface
809 * register allocation, or performance monitoring), or mmap the buffer memory
810 * synchronously after calling drm_gem_mmap_obj.
811 *
812 * This function is mainly intended to implement the DMABUF mmap operation, when
813 * the GEM object is not looked up based on its fake offset. To implement the
814 * DRM mmap operation, drivers should use the drm_gem_mmap() function.
815 *
816 * drm_gem_mmap_obj() assumes the user is granted access to the buffer while
817 * drm_gem_mmap() prevents unprivileged users from mapping random objects. So
818 * callers must verify access restrictions before calling this helper.
819 *
820 * NOTE: This function has to be protected with dev->struct_mutex
821 *
822 * Return 0 or success or -EINVAL if the object size is smaller than the VMA
823 * size, or if no gem_vm_ops are provided.
824 */
825int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
826 struct vm_area_struct *vma)
827{
828 struct drm_device *dev = obj->dev;
829
830 lockdep_assert_held(&dev->struct_mutex);
831
832 /* Check for valid size. */
833 if (obj_size < vma->vm_end - vma->vm_start)
834 return -EINVAL;
835
836 if (!dev->driver->gem_vm_ops)
837 return -EINVAL;
838
839 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
840 vma->vm_ops = dev->driver->gem_vm_ops;
841 vma->vm_private_data = obj;
842 vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
843
844 /* Take a ref for this mapping of the object, so that the fault
845 * handler can dereference the mmap offset's pointer to the object.
846 * This reference is cleaned up by the corresponding vm_close
847 * (which should happen whether the vma was created by this call, or
848 * by a vm_open due to mremap or partial unmap or whatever).
849 */
850 drm_gem_object_reference(obj);
851
852 drm_vm_open_locked(dev, vma);
853 return 0;
854}
855EXPORT_SYMBOL(drm_gem_mmap_obj);
856
857/**
858 * drm_gem_mmap - memory map routine for GEM objects
859 * @filp: DRM file pointer
860 * @vma: VMA for the area to be mapped
861 *
862 * If a driver supports GEM object mapping, mmap calls on the DRM file
863 * descriptor will end up here.
864 *
865 * Look up the GEM object based on the offset passed in (vma->vm_pgoff will
866 * contain the fake offset we created when the GTT map ioctl was called on
867 * the object) and map it with a call to drm_gem_mmap_obj().
868 *
869 * If the caller is not granted access to the buffer object, the mmap will fail
870 * with EACCES. Please see the vma manager for more information.
871 */
872int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
873{
874 struct drm_file *priv = filp->private_data;
875 struct drm_device *dev = priv->minor->dev;
876 struct drm_gem_object *obj;
877 struct drm_vma_offset_node *node;
878 int ret;
879
880 if (drm_device_is_unplugged(dev))
881 return -ENODEV;
882
883 mutex_lock(&dev->struct_mutex);
884
885 node = drm_vma_offset_exact_lookup(dev->vma_offset_manager,
886 vma->vm_pgoff,
887 vma_pages(vma));
888 if (!node) {
889 mutex_unlock(&dev->struct_mutex);
890 return drm_mmap(filp, vma);
891 } else if (!drm_vma_node_is_allowed(node, filp)) {
892 mutex_unlock(&dev->struct_mutex);
893 return -EACCES;
894 }
895
896 obj = container_of(node, struct drm_gem_object, vma_node);
897 ret = drm_gem_mmap_obj(obj, drm_vma_node_size(node) << PAGE_SHIFT, vma);
898
899 mutex_unlock(&dev->struct_mutex);
900
901 return ret;
902}
903EXPORT_SYMBOL(drm_gem_mmap);
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 */
93int
94drm_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
115void
116drm_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 */
133int 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}
148EXPORT_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 */
160void 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}
173EXPORT_SYMBOL(drm_gem_private_object_init);
174
175static void
176drm_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 */
200static 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
211static 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
220static void
221drm_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 */
251static int
252drm_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);
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 */
279int
280drm_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}
311EXPORT_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 */
322int 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}
328EXPORT_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 */
344int
345drm_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);
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
388err_revoke:
389 drm_vma_node_revoke(&obj->vma_node, file_priv);
390err_remove:
391 spin_lock(&file_priv->table_lock);
392 idr_remove(&file_priv->object_idr, handle);
393 spin_unlock(&file_priv->table_lock);
394err_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 */
409int 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}
417EXPORT_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 */
430void
431drm_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}
437EXPORT_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 */
456int
457drm_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}
464EXPORT_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 */
480int drm_gem_create_mmap_offset(struct drm_gem_object *obj)
481{
482 return drm_gem_create_mmap_offset_size(obj, obj->size);
483}
484EXPORT_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 */
507struct 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 = obj->filp->f_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
545fail:
546 while (i--)
547 put_page(pages[i]);
548
549 drm_free_large(pages);
550 return ERR_CAST(p);
551}
552EXPORT_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 */
561void 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}
587EXPORT_SYMBOL(drm_gem_put_pages);
588
589/**
590 * drm_gem_object_lookup - look up a GEM object from it's handle
591 * @filp: DRM file private date
592 * @handle: userspace handle
593 *
594 * Returns:
595 *
596 * A reference to the object named by the handle if such exists on @filp, NULL
597 * otherwise.
598 */
599struct drm_gem_object *
600drm_gem_object_lookup(struct drm_file *filp, u32 handle)
601{
602 struct drm_gem_object *obj;
603
604 spin_lock(&filp->table_lock);
605
606 /* Check if we currently have a reference on the object */
607 obj = idr_find(&filp->object_idr, handle);
608 if (obj)
609 drm_gem_object_reference(obj);
610
611 spin_unlock(&filp->table_lock);
612
613 return obj;
614}
615EXPORT_SYMBOL(drm_gem_object_lookup);
616
617/**
618 * drm_gem_close_ioctl - implementation of the GEM_CLOSE ioctl
619 * @dev: drm_device
620 * @data: ioctl data
621 * @file_priv: drm file-private structure
622 *
623 * Releases the handle to an mm object.
624 */
625int
626drm_gem_close_ioctl(struct drm_device *dev, void *data,
627 struct drm_file *file_priv)
628{
629 struct drm_gem_close *args = data;
630 int ret;
631
632 if (!drm_core_check_feature(dev, DRIVER_GEM))
633 return -ENODEV;
634
635 ret = drm_gem_handle_delete(file_priv, args->handle);
636
637 return ret;
638}
639
640/**
641 * drm_gem_flink_ioctl - implementation of the GEM_FLINK ioctl
642 * @dev: drm_device
643 * @data: ioctl data
644 * @file_priv: drm file-private structure
645 *
646 * Create a global name for an object, returning the name.
647 *
648 * Note that the name does not hold a reference; when the object
649 * is freed, the name goes away.
650 */
651int
652drm_gem_flink_ioctl(struct drm_device *dev, void *data,
653 struct drm_file *file_priv)
654{
655 struct drm_gem_flink *args = data;
656 struct drm_gem_object *obj;
657 int ret;
658
659 if (!drm_core_check_feature(dev, DRIVER_GEM))
660 return -ENODEV;
661
662 obj = drm_gem_object_lookup(file_priv, args->handle);
663 if (obj == NULL)
664 return -ENOENT;
665
666 mutex_lock(&dev->object_name_lock);
667 /* prevent races with concurrent gem_close. */
668 if (obj->handle_count == 0) {
669 ret = -ENOENT;
670 goto err;
671 }
672
673 if (!obj->name) {
674 ret = idr_alloc(&dev->object_name_idr, obj, 1, 0, GFP_KERNEL);
675 if (ret < 0)
676 goto err;
677
678 obj->name = ret;
679 }
680
681 args->name = (uint64_t) obj->name;
682 ret = 0;
683
684err:
685 mutex_unlock(&dev->object_name_lock);
686 drm_gem_object_unreference_unlocked(obj);
687 return ret;
688}
689
690/**
691 * drm_gem_open - implementation of the GEM_OPEN ioctl
692 * @dev: drm_device
693 * @data: ioctl data
694 * @file_priv: drm file-private structure
695 *
696 * Open an object using the global name, returning a handle and the size.
697 *
698 * This handle (of course) holds a reference to the object, so the object
699 * will not go away until the handle is deleted.
700 */
701int
702drm_gem_open_ioctl(struct drm_device *dev, void *data,
703 struct drm_file *file_priv)
704{
705 struct drm_gem_open *args = data;
706 struct drm_gem_object *obj;
707 int ret;
708 u32 handle;
709
710 if (!drm_core_check_feature(dev, DRIVER_GEM))
711 return -ENODEV;
712
713 mutex_lock(&dev->object_name_lock);
714 obj = idr_find(&dev->object_name_idr, (int) args->name);
715 if (obj) {
716 drm_gem_object_reference(obj);
717 } else {
718 mutex_unlock(&dev->object_name_lock);
719 return -ENOENT;
720 }
721
722 /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */
723 ret = drm_gem_handle_create_tail(file_priv, obj, &handle);
724 drm_gem_object_unreference_unlocked(obj);
725 if (ret)
726 return ret;
727
728 args->handle = handle;
729 args->size = obj->size;
730
731 return 0;
732}
733
734/**
735 * gem_gem_open - initalizes GEM file-private structures at devnode open time
736 * @dev: drm_device which is being opened by userspace
737 * @file_private: drm file-private structure to set up
738 *
739 * Called at device open time, sets up the structure for handling refcounting
740 * of mm objects.
741 */
742void
743drm_gem_open(struct drm_device *dev, struct drm_file *file_private)
744{
745 idr_init(&file_private->object_idr);
746 spin_lock_init(&file_private->table_lock);
747}
748
749/**
750 * drm_gem_release - release file-private GEM resources
751 * @dev: drm_device which is being closed by userspace
752 * @file_private: drm file-private structure to clean up
753 *
754 * Called at close time when the filp is going away.
755 *
756 * Releases any remaining references on objects by this filp.
757 */
758void
759drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
760{
761 idr_for_each(&file_private->object_idr,
762 &drm_gem_object_release_handle, file_private);
763 idr_destroy(&file_private->object_idr);
764}
765
766/**
767 * drm_gem_object_release - release GEM buffer object resources
768 * @obj: GEM buffer object
769 *
770 * This releases any structures and resources used by @obj and is the invers of
771 * drm_gem_object_init().
772 */
773void
774drm_gem_object_release(struct drm_gem_object *obj)
775{
776 WARN_ON(obj->dma_buf);
777
778 if (obj->filp)
779 fput(obj->filp);
780
781 drm_gem_free_mmap_offset(obj);
782}
783EXPORT_SYMBOL(drm_gem_object_release);
784
785/**
786 * drm_gem_object_free - free a GEM object
787 * @kref: kref of the object to free
788 *
789 * Called after the last reference to the object has been lost.
790 * Must be called holding &drm_device->struct_mutex.
791 *
792 * Frees the object
793 */
794void
795drm_gem_object_free(struct kref *kref)
796{
797 struct drm_gem_object *obj =
798 container_of(kref, struct drm_gem_object, refcount);
799 struct drm_device *dev = obj->dev;
800
801 if (dev->driver->gem_free_object_unlocked) {
802 dev->driver->gem_free_object_unlocked(obj);
803 } else if (dev->driver->gem_free_object) {
804 WARN_ON(!mutex_is_locked(&dev->struct_mutex));
805
806 dev->driver->gem_free_object(obj);
807 }
808}
809EXPORT_SYMBOL(drm_gem_object_free);
810
811/**
812 * drm_gem_object_unreference_unlocked - release a GEM BO reference
813 * @obj: GEM buffer object
814 *
815 * This releases a reference to @obj. Callers must not hold the
816 * dev->struct_mutex lock when calling this function.
817 *
818 * See also __drm_gem_object_unreference().
819 */
820void
821drm_gem_object_unreference_unlocked(struct drm_gem_object *obj)
822{
823 struct drm_device *dev;
824
825 if (!obj)
826 return;
827
828 dev = obj->dev;
829 might_lock(&dev->struct_mutex);
830
831 if (dev->driver->gem_free_object_unlocked)
832 kref_put(&obj->refcount, drm_gem_object_free);
833 else if (kref_put_mutex(&obj->refcount, drm_gem_object_free,
834 &dev->struct_mutex))
835 mutex_unlock(&dev->struct_mutex);
836}
837EXPORT_SYMBOL(drm_gem_object_unreference_unlocked);
838
839/**
840 * drm_gem_object_unreference - release a GEM BO reference
841 * @obj: GEM buffer object
842 *
843 * This releases a reference to @obj. Callers must hold the dev->struct_mutex
844 * lock when calling this function, even when the driver doesn't use
845 * dev->struct_mutex for anything.
846 *
847 * For drivers not encumbered with legacy locking use
848 * drm_gem_object_unreference_unlocked() instead.
849 */
850void
851drm_gem_object_unreference(struct drm_gem_object *obj)
852{
853 if (obj) {
854 WARN_ON(!mutex_is_locked(&obj->dev->struct_mutex));
855
856 kref_put(&obj->refcount, drm_gem_object_free);
857 }
858}
859EXPORT_SYMBOL(drm_gem_object_unreference);
860
861/**
862 * drm_gem_vm_open - vma->ops->open implementation for GEM
863 * @vma: VM area structure
864 *
865 * This function implements the #vm_operations_struct open() callback for GEM
866 * drivers. This must be used together with drm_gem_vm_close().
867 */
868void drm_gem_vm_open(struct vm_area_struct *vma)
869{
870 struct drm_gem_object *obj = vma->vm_private_data;
871
872 drm_gem_object_reference(obj);
873}
874EXPORT_SYMBOL(drm_gem_vm_open);
875
876/**
877 * drm_gem_vm_close - vma->ops->close implementation for GEM
878 * @vma: VM area structure
879 *
880 * This function implements the #vm_operations_struct close() callback for GEM
881 * drivers. This must be used together with drm_gem_vm_open().
882 */
883void drm_gem_vm_close(struct vm_area_struct *vma)
884{
885 struct drm_gem_object *obj = vma->vm_private_data;
886
887 drm_gem_object_unreference_unlocked(obj);
888}
889EXPORT_SYMBOL(drm_gem_vm_close);
890
891/**
892 * drm_gem_mmap_obj - memory map a GEM object
893 * @obj: the GEM object to map
894 * @obj_size: the object size to be mapped, in bytes
895 * @vma: VMA for the area to be mapped
896 *
897 * Set up the VMA to prepare mapping of the GEM object using the gem_vm_ops
898 * provided by the driver. Depending on their requirements, drivers can either
899 * provide a fault handler in their gem_vm_ops (in which case any accesses to
900 * the object will be trapped, to perform migration, GTT binding, surface
901 * register allocation, or performance monitoring), or mmap the buffer memory
902 * synchronously after calling drm_gem_mmap_obj.
903 *
904 * This function is mainly intended to implement the DMABUF mmap operation, when
905 * the GEM object is not looked up based on its fake offset. To implement the
906 * DRM mmap operation, drivers should use the drm_gem_mmap() function.
907 *
908 * drm_gem_mmap_obj() assumes the user is granted access to the buffer while
909 * drm_gem_mmap() prevents unprivileged users from mapping random objects. So
910 * callers must verify access restrictions before calling this helper.
911 *
912 * Return 0 or success or -EINVAL if the object size is smaller than the VMA
913 * size, or if no gem_vm_ops are provided.
914 */
915int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
916 struct vm_area_struct *vma)
917{
918 struct drm_device *dev = obj->dev;
919
920 /* Check for valid size. */
921 if (obj_size < vma->vm_end - vma->vm_start)
922 return -EINVAL;
923
924 if (!dev->driver->gem_vm_ops)
925 return -EINVAL;
926
927 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
928 vma->vm_ops = dev->driver->gem_vm_ops;
929 vma->vm_private_data = obj;
930 vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
931
932 /* Take a ref for this mapping of the object, so that the fault
933 * handler can dereference the mmap offset's pointer to the object.
934 * This reference is cleaned up by the corresponding vm_close
935 * (which should happen whether the vma was created by this call, or
936 * by a vm_open due to mremap or partial unmap or whatever).
937 */
938 drm_gem_object_reference(obj);
939
940 return 0;
941}
942EXPORT_SYMBOL(drm_gem_mmap_obj);
943
944/**
945 * drm_gem_mmap - memory map routine for GEM objects
946 * @filp: DRM file pointer
947 * @vma: VMA for the area to be mapped
948 *
949 * If a driver supports GEM object mapping, mmap calls on the DRM file
950 * descriptor will end up here.
951 *
952 * Look up the GEM object based on the offset passed in (vma->vm_pgoff will
953 * contain the fake offset we created when the GTT map ioctl was called on
954 * the object) and map it with a call to drm_gem_mmap_obj().
955 *
956 * If the caller is not granted access to the buffer object, the mmap will fail
957 * with EACCES. Please see the vma manager for more information.
958 */
959int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
960{
961 struct drm_file *priv = filp->private_data;
962 struct drm_device *dev = priv->minor->dev;
963 struct drm_gem_object *obj = NULL;
964 struct drm_vma_offset_node *node;
965 int ret;
966
967 if (drm_device_is_unplugged(dev))
968 return -ENODEV;
969
970 drm_vma_offset_lock_lookup(dev->vma_offset_manager);
971 node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager,
972 vma->vm_pgoff,
973 vma_pages(vma));
974 if (likely(node)) {
975 obj = container_of(node, struct drm_gem_object, vma_node);
976 /*
977 * When the object is being freed, after it hits 0-refcnt it
978 * proceeds to tear down the object. In the process it will
979 * attempt to remove the VMA offset and so acquire this
980 * mgr->vm_lock. Therefore if we find an object with a 0-refcnt
981 * that matches our range, we know it is in the process of being
982 * destroyed and will be freed as soon as we release the lock -
983 * so we have to check for the 0-refcnted object and treat it as
984 * invalid.
985 */
986 if (!kref_get_unless_zero(&obj->refcount))
987 obj = NULL;
988 }
989 drm_vma_offset_unlock_lookup(dev->vma_offset_manager);
990
991 if (!obj)
992 return -EINVAL;
993
994 if (!drm_vma_node_is_allowed(node, priv)) {
995 drm_gem_object_unreference_unlocked(obj);
996 return -EACCES;
997 }
998
999 ret = drm_gem_mmap_obj(obj, drm_vma_node_size(node) << PAGE_SHIFT,
1000 vma);
1001
1002 drm_gem_object_unreference_unlocked(obj);
1003
1004 return ret;
1005}
1006EXPORT_SYMBOL(drm_gem_mmap);