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