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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 <linux/mem_encrypt.h>
40#include <drm/drmP.h>
41#include <drm/drm_vma_manager.h>
42#include <drm/drm_gem.h>
43#include <drm/drm_print.h>
44#include "drm_internal.h"
45
46/** @file drm_gem.c
47 *
48 * This file provides some of the base ioctls and library routines for
49 * the graphics memory manager implemented by each device driver.
50 *
51 * Because various devices have different requirements in terms of
52 * synchronization and migration strategies, implementing that is left up to
53 * the driver, and all that the general API provides should be generic --
54 * allocating objects, reading/writing data with the cpu, freeing objects.
55 * Even there, platform-dependent optimizations for reading/writing data with
56 * the CPU mean we'll likely hook those out to driver-specific calls. However,
57 * the DRI2 implementation wants to have at least allocate/mmap be generic.
58 *
59 * The goal was to have swap-backed object allocation managed through
60 * struct file. However, file descriptors as handles to a struct file have
61 * two major failings:
62 * - Process limits prevent more than 1024 or so being used at a time by
63 * default.
64 * - Inability to allocate high fds will aggravate the X Server's select()
65 * handling, and likely that of many GL client applications as well.
66 *
67 * This led to a plan of using our own integer IDs (called handles, following
68 * DRM terminology) to mimic fds, and implement the fd syscalls we need as
69 * ioctls. The objects themselves will still include the struct file so
70 * that we can transition to fds if the required kernel infrastructure shows
71 * up at a later date, and as our interface with shmfs for memory allocation.
72 */
73
74/*
75 * We make up offsets for buffer objects so we can recognize them at
76 * mmap time.
77 */
78
79/* pgoff in mmap is an unsigned long, so we need to make sure that
80 * the faked up offset will fit
81 */
82
83#if BITS_PER_LONG == 64
84#define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFFUL >> PAGE_SHIFT) + 1)
85#define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFFUL >> PAGE_SHIFT) * 16)
86#else
87#define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFUL >> PAGE_SHIFT) + 1)
88#define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFUL >> PAGE_SHIFT) * 16)
89#endif
90
91/**
92 * drm_gem_init - Initialize the GEM device fields
93 * @dev: drm_devic structure to initialize
94 */
95int
96drm_gem_init(struct drm_device *dev)
97{
98 struct drm_vma_offset_manager *vma_offset_manager;
99
100 mutex_init(&dev->object_name_lock);
101 idr_init_base(&dev->object_name_idr, 1);
102
103 vma_offset_manager = kzalloc(sizeof(*vma_offset_manager), GFP_KERNEL);
104 if (!vma_offset_manager) {
105 DRM_ERROR("out of memory\n");
106 return -ENOMEM;
107 }
108
109 dev->vma_offset_manager = vma_offset_manager;
110 drm_vma_offset_manager_init(vma_offset_manager,
111 DRM_FILE_PAGE_OFFSET_START,
112 DRM_FILE_PAGE_OFFSET_SIZE);
113
114 return 0;
115}
116
117void
118drm_gem_destroy(struct drm_device *dev)
119{
120
121 drm_vma_offset_manager_destroy(dev->vma_offset_manager);
122 kfree(dev->vma_offset_manager);
123 dev->vma_offset_manager = NULL;
124}
125
126/**
127 * drm_gem_object_init - initialize an allocated shmem-backed GEM object
128 * @dev: drm_device the object should be initialized for
129 * @obj: drm_gem_object to initialize
130 * @size: object size
131 *
132 * Initialize an already allocated GEM object of the specified size with
133 * shmfs backing store.
134 */
135int drm_gem_object_init(struct drm_device *dev,
136 struct drm_gem_object *obj, size_t size)
137{
138 struct file *filp;
139
140 drm_gem_private_object_init(dev, obj, size);
141
142 filp = shmem_file_setup("drm mm object", size, VM_NORESERVE);
143 if (IS_ERR(filp))
144 return PTR_ERR(filp);
145
146 obj->filp = filp;
147
148 return 0;
149}
150EXPORT_SYMBOL(drm_gem_object_init);
151
152/**
153 * drm_gem_private_object_init - initialize an allocated private GEM object
154 * @dev: drm_device the object should be initialized for
155 * @obj: drm_gem_object to initialize
156 * @size: object size
157 *
158 * Initialize an already allocated GEM object of the specified size with
159 * no GEM provided backing store. Instead the caller is responsible for
160 * backing the object and handling it.
161 */
162void drm_gem_private_object_init(struct drm_device *dev,
163 struct drm_gem_object *obj, size_t size)
164{
165 BUG_ON((size & (PAGE_SIZE - 1)) != 0);
166
167 obj->dev = dev;
168 obj->filp = NULL;
169
170 kref_init(&obj->refcount);
171 obj->handle_count = 0;
172 obj->size = size;
173 drm_vma_node_reset(&obj->vma_node);
174}
175EXPORT_SYMBOL(drm_gem_private_object_init);
176
177static void
178drm_gem_remove_prime_handles(struct drm_gem_object *obj, struct drm_file *filp)
179{
180 /*
181 * Note: obj->dma_buf can't disappear as long as we still hold a
182 * handle reference in obj->handle_count.
183 */
184 mutex_lock(&filp->prime.lock);
185 if (obj->dma_buf) {
186 drm_prime_remove_buf_handle_locked(&filp->prime,
187 obj->dma_buf);
188 }
189 mutex_unlock(&filp->prime.lock);
190}
191
192/**
193 * drm_gem_object_handle_free - release resources bound to userspace handles
194 * @obj: GEM object to clean up.
195 *
196 * Called after the last handle to the object has been closed
197 *
198 * Removes any name for the object. Note that this must be
199 * called before drm_gem_object_free or we'll be touching
200 * freed memory
201 */
202static void drm_gem_object_handle_free(struct drm_gem_object *obj)
203{
204 struct drm_device *dev = obj->dev;
205
206 /* Remove any name for this object */
207 if (obj->name) {
208 idr_remove(&dev->object_name_idr, obj->name);
209 obj->name = 0;
210 }
211}
212
213static void drm_gem_object_exported_dma_buf_free(struct drm_gem_object *obj)
214{
215 /* Unbreak the reference cycle if we have an exported dma_buf. */
216 if (obj->dma_buf) {
217 dma_buf_put(obj->dma_buf);
218 obj->dma_buf = NULL;
219 }
220}
221
222static void
223drm_gem_object_handle_put_unlocked(struct drm_gem_object *obj)
224{
225 struct drm_device *dev = obj->dev;
226 bool final = false;
227
228 if (WARN_ON(obj->handle_count == 0))
229 return;
230
231 /*
232 * Must bump handle count first as this may be the last
233 * ref, in which case the object would disappear before we
234 * checked for a name
235 */
236
237 mutex_lock(&dev->object_name_lock);
238 if (--obj->handle_count == 0) {
239 drm_gem_object_handle_free(obj);
240 drm_gem_object_exported_dma_buf_free(obj);
241 final = true;
242 }
243 mutex_unlock(&dev->object_name_lock);
244
245 if (final)
246 drm_gem_object_put_unlocked(obj);
247}
248
249/*
250 * Called at device or object close to release the file's
251 * handle references on objects.
252 */
253static int
254drm_gem_object_release_handle(int id, void *ptr, void *data)
255{
256 struct drm_file *file_priv = data;
257 struct drm_gem_object *obj = ptr;
258 struct drm_device *dev = obj->dev;
259
260 if (dev->driver->gem_close_object)
261 dev->driver->gem_close_object(obj, file_priv);
262
263 if (drm_core_check_feature(dev, DRIVER_PRIME))
264 drm_gem_remove_prime_handles(obj, file_priv);
265 drm_vma_node_revoke(&obj->vma_node, file_priv);
266
267 drm_gem_object_handle_put_unlocked(obj);
268
269 return 0;
270}
271
272/**
273 * drm_gem_handle_delete - deletes the given file-private handle
274 * @filp: drm file-private structure to use for the handle look up
275 * @handle: userspace handle to delete
276 *
277 * Removes the GEM handle from the @filp lookup table which has been added with
278 * drm_gem_handle_create(). If this is the last handle also cleans up linked
279 * resources like GEM names.
280 */
281int
282drm_gem_handle_delete(struct drm_file *filp, u32 handle)
283{
284 struct drm_gem_object *obj;
285
286 spin_lock(&filp->table_lock);
287
288 /* Check if we currently have a reference on the object */
289 obj = idr_replace(&filp->object_idr, NULL, handle);
290 spin_unlock(&filp->table_lock);
291 if (IS_ERR_OR_NULL(obj))
292 return -EINVAL;
293
294 /* Release driver's reference and decrement refcount. */
295 drm_gem_object_release_handle(handle, obj, filp);
296
297 /* And finally make the handle available for future allocations. */
298 spin_lock(&filp->table_lock);
299 idr_remove(&filp->object_idr, handle);
300 spin_unlock(&filp->table_lock);
301
302 return 0;
303}
304EXPORT_SYMBOL(drm_gem_handle_delete);
305
306/**
307 * drm_gem_dumb_map_offset - return the fake mmap offset for a gem object
308 * @file: drm file-private structure containing the gem object
309 * @dev: corresponding drm_device
310 * @handle: gem object handle
311 * @offset: return location for the fake mmap offset
312 *
313 * This implements the &drm_driver.dumb_map_offset kms driver callback for
314 * drivers which use gem to manage their backing storage.
315 *
316 * Returns:
317 * 0 on success or a negative error code on failure.
318 */
319int drm_gem_dumb_map_offset(struct drm_file *file, struct drm_device *dev,
320 u32 handle, u64 *offset)
321{
322 struct drm_gem_object *obj;
323 int ret;
324
325 obj = drm_gem_object_lookup(file, handle);
326 if (!obj)
327 return -ENOENT;
328
329 /* Don't allow imported objects to be mapped */
330 if (obj->import_attach) {
331 ret = -EINVAL;
332 goto out;
333 }
334
335 ret = drm_gem_create_mmap_offset(obj);
336 if (ret)
337 goto out;
338
339 *offset = drm_vma_node_offset_addr(&obj->vma_node);
340out:
341 drm_gem_object_put_unlocked(obj);
342
343 return ret;
344}
345EXPORT_SYMBOL_GPL(drm_gem_dumb_map_offset);
346
347/**
348 * drm_gem_dumb_destroy - dumb fb callback helper for gem based drivers
349 * @file: drm file-private structure to remove the dumb handle from
350 * @dev: corresponding drm_device
351 * @handle: the dumb handle to remove
352 *
353 * This implements the &drm_driver.dumb_destroy kms driver callback for drivers
354 * which use gem to manage their backing storage.
355 */
356int drm_gem_dumb_destroy(struct drm_file *file,
357 struct drm_device *dev,
358 uint32_t handle)
359{
360 return drm_gem_handle_delete(file, handle);
361}
362EXPORT_SYMBOL(drm_gem_dumb_destroy);
363
364/**
365 * drm_gem_handle_create_tail - internal functions to create a handle
366 * @file_priv: drm file-private structure to register the handle for
367 * @obj: object to register
368 * @handlep: pointer to return the created handle to the caller
369 *
370 * This expects the &drm_device.object_name_lock to be held already and will
371 * drop it before returning. Used to avoid races in establishing new handles
372 * when importing an object from either an flink name or a dma-buf.
373 *
374 * Handles must be release again through drm_gem_handle_delete(). This is done
375 * when userspace closes @file_priv for all attached handles, or through the
376 * GEM_CLOSE ioctl for individual handles.
377 */
378int
379drm_gem_handle_create_tail(struct drm_file *file_priv,
380 struct drm_gem_object *obj,
381 u32 *handlep)
382{
383 struct drm_device *dev = obj->dev;
384 u32 handle;
385 int ret;
386
387 WARN_ON(!mutex_is_locked(&dev->object_name_lock));
388 if (obj->handle_count++ == 0)
389 drm_gem_object_get(obj);
390
391 /*
392 * Get the user-visible handle using idr. Preload and perform
393 * allocation under our spinlock.
394 */
395 idr_preload(GFP_KERNEL);
396 spin_lock(&file_priv->table_lock);
397
398 ret = idr_alloc(&file_priv->object_idr, obj, 1, 0, GFP_NOWAIT);
399
400 spin_unlock(&file_priv->table_lock);
401 idr_preload_end();
402
403 mutex_unlock(&dev->object_name_lock);
404 if (ret < 0)
405 goto err_unref;
406
407 handle = ret;
408
409 ret = drm_vma_node_allow(&obj->vma_node, file_priv);
410 if (ret)
411 goto err_remove;
412
413 if (dev->driver->gem_open_object) {
414 ret = dev->driver->gem_open_object(obj, file_priv);
415 if (ret)
416 goto err_revoke;
417 }
418
419 *handlep = handle;
420 return 0;
421
422err_revoke:
423 drm_vma_node_revoke(&obj->vma_node, file_priv);
424err_remove:
425 spin_lock(&file_priv->table_lock);
426 idr_remove(&file_priv->object_idr, handle);
427 spin_unlock(&file_priv->table_lock);
428err_unref:
429 drm_gem_object_handle_put_unlocked(obj);
430 return ret;
431}
432
433/**
434 * drm_gem_handle_create - create a gem handle for an object
435 * @file_priv: drm file-private structure to register the handle for
436 * @obj: object to register
437 * @handlep: pionter to return the created handle to the caller
438 *
439 * Create a handle for this object. This adds a handle reference
440 * to the object, which includes a regular reference count. Callers
441 * will likely want to dereference the object afterwards.
442 */
443int drm_gem_handle_create(struct drm_file *file_priv,
444 struct drm_gem_object *obj,
445 u32 *handlep)
446{
447 mutex_lock(&obj->dev->object_name_lock);
448
449 return drm_gem_handle_create_tail(file_priv, obj, handlep);
450}
451EXPORT_SYMBOL(drm_gem_handle_create);
452
453
454/**
455 * drm_gem_free_mmap_offset - release a fake mmap offset for an object
456 * @obj: obj in question
457 *
458 * This routine frees fake offsets allocated by drm_gem_create_mmap_offset().
459 *
460 * Note that drm_gem_object_release() already calls this function, so drivers
461 * don't have to take care of releasing the mmap offset themselves when freeing
462 * the GEM object.
463 */
464void
465drm_gem_free_mmap_offset(struct drm_gem_object *obj)
466{
467 struct drm_device *dev = obj->dev;
468
469 drm_vma_offset_remove(dev->vma_offset_manager, &obj->vma_node);
470}
471EXPORT_SYMBOL(drm_gem_free_mmap_offset);
472
473/**
474 * drm_gem_create_mmap_offset_size - create a fake mmap offset for an object
475 * @obj: obj in question
476 * @size: the virtual size
477 *
478 * GEM memory mapping works by handing back to userspace a fake mmap offset
479 * it can use in a subsequent mmap(2) call. The DRM core code then looks
480 * up the object based on the offset and sets up the various memory mapping
481 * structures.
482 *
483 * This routine allocates and attaches a fake offset for @obj, in cases where
484 * the virtual size differs from the physical size (ie. &drm_gem_object.size).
485 * Otherwise just use drm_gem_create_mmap_offset().
486 *
487 * This function is idempotent and handles an already allocated mmap offset
488 * transparently. Drivers do not need to check for this case.
489 */
490int
491drm_gem_create_mmap_offset_size(struct drm_gem_object *obj, size_t size)
492{
493 struct drm_device *dev = obj->dev;
494
495 return drm_vma_offset_add(dev->vma_offset_manager, &obj->vma_node,
496 size / PAGE_SIZE);
497}
498EXPORT_SYMBOL(drm_gem_create_mmap_offset_size);
499
500/**
501 * drm_gem_create_mmap_offset - create a fake mmap offset for an object
502 * @obj: obj in question
503 *
504 * GEM memory mapping works by handing back to userspace a fake mmap offset
505 * it can use in a subsequent mmap(2) call. The DRM core code then looks
506 * up the object based on the offset and sets up the various memory mapping
507 * structures.
508 *
509 * This routine allocates and attaches a fake offset for @obj.
510 *
511 * Drivers can call drm_gem_free_mmap_offset() before freeing @obj to release
512 * the fake offset again.
513 */
514int drm_gem_create_mmap_offset(struct drm_gem_object *obj)
515{
516 return drm_gem_create_mmap_offset_size(obj, obj->size);
517}
518EXPORT_SYMBOL(drm_gem_create_mmap_offset);
519
520/**
521 * drm_gem_get_pages - helper to allocate backing pages for a GEM object
522 * from shmem
523 * @obj: obj in question
524 *
525 * This reads the page-array of the shmem-backing storage of the given gem
526 * object. An array of pages is returned. If a page is not allocated or
527 * swapped-out, this will allocate/swap-in the required pages. Note that the
528 * whole object is covered by the page-array and pinned in memory.
529 *
530 * Use drm_gem_put_pages() to release the array and unpin all pages.
531 *
532 * This uses the GFP-mask set on the shmem-mapping (see mapping_set_gfp_mask()).
533 * If you require other GFP-masks, you have to do those allocations yourself.
534 *
535 * Note that you are not allowed to change gfp-zones during runtime. That is,
536 * shmem_read_mapping_page_gfp() must be called with the same gfp_zone(gfp) as
537 * set during initialization. If you have special zone constraints, set them
538 * after drm_gem_object_init() via mapping_set_gfp_mask(). shmem-core takes care
539 * to keep pages in the required zone during swap-in.
540 */
541struct page **drm_gem_get_pages(struct drm_gem_object *obj)
542{
543 struct address_space *mapping;
544 struct page *p, **pages;
545 int i, npages;
546
547 /* This is the shared memory object that backs the GEM resource */
548 mapping = obj->filp->f_mapping;
549
550 /* We already BUG_ON() for non-page-aligned sizes in
551 * drm_gem_object_init(), so we should never hit this unless
552 * driver author is doing something really wrong:
553 */
554 WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0);
555
556 npages = obj->size >> PAGE_SHIFT;
557
558 pages = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
559 if (pages == NULL)
560 return ERR_PTR(-ENOMEM);
561
562 for (i = 0; i < npages; i++) {
563 p = shmem_read_mapping_page(mapping, i);
564 if (IS_ERR(p))
565 goto fail;
566 pages[i] = p;
567
568 /* Make sure shmem keeps __GFP_DMA32 allocated pages in the
569 * correct region during swapin. Note that this requires
570 * __GFP_DMA32 to be set in mapping_gfp_mask(inode->i_mapping)
571 * so shmem can relocate pages during swapin if required.
572 */
573 BUG_ON(mapping_gfp_constraint(mapping, __GFP_DMA32) &&
574 (page_to_pfn(p) >= 0x00100000UL));
575 }
576
577 return pages;
578
579fail:
580 while (i--)
581 put_page(pages[i]);
582
583 kvfree(pages);
584 return ERR_CAST(p);
585}
586EXPORT_SYMBOL(drm_gem_get_pages);
587
588/**
589 * drm_gem_put_pages - helper to free backing pages for a GEM object
590 * @obj: obj in question
591 * @pages: pages to free
592 * @dirty: if true, pages will be marked as dirty
593 * @accessed: if true, the pages will be marked as accessed
594 */
595void drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages,
596 bool dirty, bool accessed)
597{
598 int i, npages;
599
600 /* We already BUG_ON() for non-page-aligned sizes in
601 * drm_gem_object_init(), so we should never hit this unless
602 * driver author is doing something really wrong:
603 */
604 WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0);
605
606 npages = obj->size >> PAGE_SHIFT;
607
608 for (i = 0; i < npages; i++) {
609 if (dirty)
610 set_page_dirty(pages[i]);
611
612 if (accessed)
613 mark_page_accessed(pages[i]);
614
615 /* Undo the reference we took when populating the table */
616 put_page(pages[i]);
617 }
618
619 kvfree(pages);
620}
621EXPORT_SYMBOL(drm_gem_put_pages);
622
623/**
624 * drm_gem_object_lookup - look up a GEM object from it's handle
625 * @filp: DRM file private date
626 * @handle: userspace handle
627 *
628 * Returns:
629 *
630 * A reference to the object named by the handle if such exists on @filp, NULL
631 * otherwise.
632 */
633struct drm_gem_object *
634drm_gem_object_lookup(struct drm_file *filp, u32 handle)
635{
636 struct drm_gem_object *obj;
637
638 spin_lock(&filp->table_lock);
639
640 /* Check if we currently have a reference on the object */
641 obj = idr_find(&filp->object_idr, handle);
642 if (obj)
643 drm_gem_object_get(obj);
644
645 spin_unlock(&filp->table_lock);
646
647 return obj;
648}
649EXPORT_SYMBOL(drm_gem_object_lookup);
650
651/**
652 * drm_gem_close_ioctl - implementation of the GEM_CLOSE ioctl
653 * @dev: drm_device
654 * @data: ioctl data
655 * @file_priv: drm file-private structure
656 *
657 * Releases the handle to an mm object.
658 */
659int
660drm_gem_close_ioctl(struct drm_device *dev, void *data,
661 struct drm_file *file_priv)
662{
663 struct drm_gem_close *args = data;
664 int ret;
665
666 if (!drm_core_check_feature(dev, DRIVER_GEM))
667 return -ENODEV;
668
669 ret = drm_gem_handle_delete(file_priv, args->handle);
670
671 return ret;
672}
673
674/**
675 * drm_gem_flink_ioctl - implementation of the GEM_FLINK ioctl
676 * @dev: drm_device
677 * @data: ioctl data
678 * @file_priv: drm file-private structure
679 *
680 * Create a global name for an object, returning the name.
681 *
682 * Note that the name does not hold a reference; when the object
683 * is freed, the name goes away.
684 */
685int
686drm_gem_flink_ioctl(struct drm_device *dev, void *data,
687 struct drm_file *file_priv)
688{
689 struct drm_gem_flink *args = data;
690 struct drm_gem_object *obj;
691 int ret;
692
693 if (!drm_core_check_feature(dev, DRIVER_GEM))
694 return -ENODEV;
695
696 obj = drm_gem_object_lookup(file_priv, args->handle);
697 if (obj == NULL)
698 return -ENOENT;
699
700 mutex_lock(&dev->object_name_lock);
701 /* prevent races with concurrent gem_close. */
702 if (obj->handle_count == 0) {
703 ret = -ENOENT;
704 goto err;
705 }
706
707 if (!obj->name) {
708 ret = idr_alloc(&dev->object_name_idr, obj, 1, 0, GFP_KERNEL);
709 if (ret < 0)
710 goto err;
711
712 obj->name = ret;
713 }
714
715 args->name = (uint64_t) obj->name;
716 ret = 0;
717
718err:
719 mutex_unlock(&dev->object_name_lock);
720 drm_gem_object_put_unlocked(obj);
721 return ret;
722}
723
724/**
725 * drm_gem_open - implementation of the GEM_OPEN ioctl
726 * @dev: drm_device
727 * @data: ioctl data
728 * @file_priv: drm file-private structure
729 *
730 * Open an object using the global name, returning a handle and the size.
731 *
732 * This handle (of course) holds a reference to the object, so the object
733 * will not go away until the handle is deleted.
734 */
735int
736drm_gem_open_ioctl(struct drm_device *dev, void *data,
737 struct drm_file *file_priv)
738{
739 struct drm_gem_open *args = data;
740 struct drm_gem_object *obj;
741 int ret;
742 u32 handle;
743
744 if (!drm_core_check_feature(dev, DRIVER_GEM))
745 return -ENODEV;
746
747 mutex_lock(&dev->object_name_lock);
748 obj = idr_find(&dev->object_name_idr, (int) args->name);
749 if (obj) {
750 drm_gem_object_get(obj);
751 } else {
752 mutex_unlock(&dev->object_name_lock);
753 return -ENOENT;
754 }
755
756 /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */
757 ret = drm_gem_handle_create_tail(file_priv, obj, &handle);
758 drm_gem_object_put_unlocked(obj);
759 if (ret)
760 return ret;
761
762 args->handle = handle;
763 args->size = obj->size;
764
765 return 0;
766}
767
768/**
769 * gem_gem_open - initalizes GEM file-private structures at devnode open time
770 * @dev: drm_device which is being opened by userspace
771 * @file_private: drm file-private structure to set up
772 *
773 * Called at device open time, sets up the structure for handling refcounting
774 * of mm objects.
775 */
776void
777drm_gem_open(struct drm_device *dev, struct drm_file *file_private)
778{
779 idr_init_base(&file_private->object_idr, 1);
780 spin_lock_init(&file_private->table_lock);
781}
782
783/**
784 * drm_gem_release - release file-private GEM resources
785 * @dev: drm_device which is being closed by userspace
786 * @file_private: drm file-private structure to clean up
787 *
788 * Called at close time when the filp is going away.
789 *
790 * Releases any remaining references on objects by this filp.
791 */
792void
793drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
794{
795 idr_for_each(&file_private->object_idr,
796 &drm_gem_object_release_handle, file_private);
797 idr_destroy(&file_private->object_idr);
798}
799
800/**
801 * drm_gem_object_release - release GEM buffer object resources
802 * @obj: GEM buffer object
803 *
804 * This releases any structures and resources used by @obj and is the invers of
805 * drm_gem_object_init().
806 */
807void
808drm_gem_object_release(struct drm_gem_object *obj)
809{
810 WARN_ON(obj->dma_buf);
811
812 if (obj->filp)
813 fput(obj->filp);
814
815 drm_gem_free_mmap_offset(obj);
816}
817EXPORT_SYMBOL(drm_gem_object_release);
818
819/**
820 * drm_gem_object_free - free a GEM object
821 * @kref: kref of the object to free
822 *
823 * Called after the last reference to the object has been lost.
824 * Must be called holding &drm_device.struct_mutex.
825 *
826 * Frees the object
827 */
828void
829drm_gem_object_free(struct kref *kref)
830{
831 struct drm_gem_object *obj =
832 container_of(kref, struct drm_gem_object, refcount);
833 struct drm_device *dev = obj->dev;
834
835 if (dev->driver->gem_free_object_unlocked) {
836 dev->driver->gem_free_object_unlocked(obj);
837 } else if (dev->driver->gem_free_object) {
838 WARN_ON(!mutex_is_locked(&dev->struct_mutex));
839
840 dev->driver->gem_free_object(obj);
841 }
842}
843EXPORT_SYMBOL(drm_gem_object_free);
844
845/**
846 * drm_gem_object_put_unlocked - drop a GEM buffer object reference
847 * @obj: GEM buffer object
848 *
849 * This releases a reference to @obj. Callers must not hold the
850 * &drm_device.struct_mutex lock when calling this function.
851 *
852 * See also __drm_gem_object_put().
853 */
854void
855drm_gem_object_put_unlocked(struct drm_gem_object *obj)
856{
857 struct drm_device *dev;
858
859 if (!obj)
860 return;
861
862 dev = obj->dev;
863
864 if (dev->driver->gem_free_object_unlocked) {
865 kref_put(&obj->refcount, drm_gem_object_free);
866 } else {
867 might_lock(&dev->struct_mutex);
868 if (kref_put_mutex(&obj->refcount, drm_gem_object_free,
869 &dev->struct_mutex))
870 mutex_unlock(&dev->struct_mutex);
871 }
872}
873EXPORT_SYMBOL(drm_gem_object_put_unlocked);
874
875/**
876 * drm_gem_object_put - release a GEM buffer object reference
877 * @obj: GEM buffer object
878 *
879 * This releases a reference to @obj. Callers must hold the
880 * &drm_device.struct_mutex lock when calling this function, even when the
881 * driver doesn't use &drm_device.struct_mutex for anything.
882 *
883 * For drivers not encumbered with legacy locking use
884 * drm_gem_object_put_unlocked() instead.
885 */
886void
887drm_gem_object_put(struct drm_gem_object *obj)
888{
889 if (obj) {
890 WARN_ON(!mutex_is_locked(&obj->dev->struct_mutex));
891
892 kref_put(&obj->refcount, drm_gem_object_free);
893 }
894}
895EXPORT_SYMBOL(drm_gem_object_put);
896
897/**
898 * drm_gem_vm_open - vma->ops->open implementation for GEM
899 * @vma: VM area structure
900 *
901 * This function implements the #vm_operations_struct open() callback for GEM
902 * drivers. This must be used together with drm_gem_vm_close().
903 */
904void drm_gem_vm_open(struct vm_area_struct *vma)
905{
906 struct drm_gem_object *obj = vma->vm_private_data;
907
908 drm_gem_object_get(obj);
909}
910EXPORT_SYMBOL(drm_gem_vm_open);
911
912/**
913 * drm_gem_vm_close - vma->ops->close implementation for GEM
914 * @vma: VM area structure
915 *
916 * This function implements the #vm_operations_struct close() callback for GEM
917 * drivers. This must be used together with drm_gem_vm_open().
918 */
919void drm_gem_vm_close(struct vm_area_struct *vma)
920{
921 struct drm_gem_object *obj = vma->vm_private_data;
922
923 drm_gem_object_put_unlocked(obj);
924}
925EXPORT_SYMBOL(drm_gem_vm_close);
926
927/**
928 * drm_gem_mmap_obj - memory map a GEM object
929 * @obj: the GEM object to map
930 * @obj_size: the object size to be mapped, in bytes
931 * @vma: VMA for the area to be mapped
932 *
933 * Set up the VMA to prepare mapping of the GEM object using the gem_vm_ops
934 * provided by the driver. Depending on their requirements, drivers can either
935 * provide a fault handler in their gem_vm_ops (in which case any accesses to
936 * the object will be trapped, to perform migration, GTT binding, surface
937 * register allocation, or performance monitoring), or mmap the buffer memory
938 * synchronously after calling drm_gem_mmap_obj.
939 *
940 * This function is mainly intended to implement the DMABUF mmap operation, when
941 * the GEM object is not looked up based on its fake offset. To implement the
942 * DRM mmap operation, drivers should use the drm_gem_mmap() function.
943 *
944 * drm_gem_mmap_obj() assumes the user is granted access to the buffer while
945 * drm_gem_mmap() prevents unprivileged users from mapping random objects. So
946 * callers must verify access restrictions before calling this helper.
947 *
948 * Return 0 or success or -EINVAL if the object size is smaller than the VMA
949 * size, or if no gem_vm_ops are provided.
950 */
951int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
952 struct vm_area_struct *vma)
953{
954 struct drm_device *dev = obj->dev;
955
956 /* Check for valid size. */
957 if (obj_size < vma->vm_end - vma->vm_start)
958 return -EINVAL;
959
960 if (!dev->driver->gem_vm_ops)
961 return -EINVAL;
962
963 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
964 vma->vm_ops = dev->driver->gem_vm_ops;
965 vma->vm_private_data = obj;
966 vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
967 vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
968
969 /* Take a ref for this mapping of the object, so that the fault
970 * handler can dereference the mmap offset's pointer to the object.
971 * This reference is cleaned up by the corresponding vm_close
972 * (which should happen whether the vma was created by this call, or
973 * by a vm_open due to mremap or partial unmap or whatever).
974 */
975 drm_gem_object_get(obj);
976
977 return 0;
978}
979EXPORT_SYMBOL(drm_gem_mmap_obj);
980
981/**
982 * drm_gem_mmap - memory map routine for GEM objects
983 * @filp: DRM file pointer
984 * @vma: VMA for the area to be mapped
985 *
986 * If a driver supports GEM object mapping, mmap calls on the DRM file
987 * descriptor will end up here.
988 *
989 * Look up the GEM object based on the offset passed in (vma->vm_pgoff will
990 * contain the fake offset we created when the GTT map ioctl was called on
991 * the object) and map it with a call to drm_gem_mmap_obj().
992 *
993 * If the caller is not granted access to the buffer object, the mmap will fail
994 * with EACCES. Please see the vma manager for more information.
995 */
996int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
997{
998 struct drm_file *priv = filp->private_data;
999 struct drm_device *dev = priv->minor->dev;
1000 struct drm_gem_object *obj = NULL;
1001 struct drm_vma_offset_node *node;
1002 int ret;
1003
1004 if (drm_dev_is_unplugged(dev))
1005 return -ENODEV;
1006
1007 drm_vma_offset_lock_lookup(dev->vma_offset_manager);
1008 node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager,
1009 vma->vm_pgoff,
1010 vma_pages(vma));
1011 if (likely(node)) {
1012 obj = container_of(node, struct drm_gem_object, vma_node);
1013 /*
1014 * When the object is being freed, after it hits 0-refcnt it
1015 * proceeds to tear down the object. In the process it will
1016 * attempt to remove the VMA offset and so acquire this
1017 * mgr->vm_lock. Therefore if we find an object with a 0-refcnt
1018 * that matches our range, we know it is in the process of being
1019 * destroyed and will be freed as soon as we release the lock -
1020 * so we have to check for the 0-refcnted object and treat it as
1021 * invalid.
1022 */
1023 if (!kref_get_unless_zero(&obj->refcount))
1024 obj = NULL;
1025 }
1026 drm_vma_offset_unlock_lookup(dev->vma_offset_manager);
1027
1028 if (!obj)
1029 return -EINVAL;
1030
1031 if (!drm_vma_node_is_allowed(node, priv)) {
1032 drm_gem_object_put_unlocked(obj);
1033 return -EACCES;
1034 }
1035
1036 ret = drm_gem_mmap_obj(obj, drm_vma_node_size(node) << PAGE_SHIFT,
1037 vma);
1038
1039 drm_gem_object_put_unlocked(obj);
1040
1041 return ret;
1042}
1043EXPORT_SYMBOL(drm_gem_mmap);
1044
1045void drm_gem_print_info(struct drm_printer *p, unsigned int indent,
1046 const struct drm_gem_object *obj)
1047{
1048 drm_printf_indent(p, indent, "name=%d\n", obj->name);
1049 drm_printf_indent(p, indent, "refcount=%u\n",
1050 kref_read(&obj->refcount));
1051 drm_printf_indent(p, indent, "start=%08lx\n",
1052 drm_vma_node_start(&obj->vma_node));
1053 drm_printf_indent(p, indent, "size=%zu\n", obj->size);
1054 drm_printf_indent(p, indent, "imported=%s\n",
1055 obj->import_attach ? "yes" : "no");
1056
1057 if (obj->dev->driver->gem_print_info)
1058 obj->dev->driver->gem_print_info(p, indent, obj);
1059}