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1/*
2 * Copyright © 2008 Intel Corporation
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 *
23 * Authors:
24 * Eric Anholt <eric@anholt.net>
25 *
26 */
27
28#include <linux/types.h>
29#include <linux/slab.h>
30#include <linux/mm.h>
31#include <linux/uaccess.h>
32#include <linux/fs.h>
33#include <linux/file.h>
34#include <linux/module.h>
35#include <linux/mman.h>
36#include <linux/pagemap.h>
37#include <linux/shmem_fs.h>
38#include <linux/dma-buf.h>
39#include <drm/drmP.h>
40#include <drm/drm_vma_manager.h>
41
42/** @file drm_gem.c
43 *
44 * This file provides some of the base ioctls and library routines for
45 * the graphics memory manager implemented by each device driver.
46 *
47 * Because various devices have different requirements in terms of
48 * synchronization and migration strategies, implementing that is left up to
49 * the driver, and all that the general API provides should be generic --
50 * allocating objects, reading/writing data with the cpu, freeing objects.
51 * Even there, platform-dependent optimizations for reading/writing data with
52 * the CPU mean we'll likely hook those out to driver-specific calls. However,
53 * the DRI2 implementation wants to have at least allocate/mmap be generic.
54 *
55 * The goal was to have swap-backed object allocation managed through
56 * struct file. However, file descriptors as handles to a struct file have
57 * two major failings:
58 * - Process limits prevent more than 1024 or so being used at a time by
59 * default.
60 * - Inability to allocate high fds will aggravate the X Server's select()
61 * handling, and likely that of many GL client applications as well.
62 *
63 * This led to a plan of using our own integer IDs (called handles, following
64 * DRM terminology) to mimic fds, and implement the fd syscalls we need as
65 * ioctls. The objects themselves will still include the struct file so
66 * that we can transition to fds if the required kernel infrastructure shows
67 * up at a later date, and as our interface with shmfs for memory allocation.
68 */
69
70/*
71 * We make up offsets for buffer objects so we can recognize them at
72 * mmap time.
73 */
74
75/* pgoff in mmap is an unsigned long, so we need to make sure that
76 * the faked up offset will fit
77 */
78
79#if BITS_PER_LONG == 64
80#define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFFUL >> PAGE_SHIFT) + 1)
81#define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFFUL >> PAGE_SHIFT) * 16)
82#else
83#define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFUL >> PAGE_SHIFT) + 1)
84#define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFUL >> PAGE_SHIFT) * 16)
85#endif
86
87/**
88 * drm_gem_init - Initialize the GEM device fields
89 * @dev: drm_devic structure to initialize
90 */
91int
92drm_gem_init(struct drm_device *dev)
93{
94 struct drm_vma_offset_manager *vma_offset_manager;
95
96 mutex_init(&dev->object_name_lock);
97 idr_init(&dev->object_name_idr);
98
99 vma_offset_manager = kzalloc(sizeof(*vma_offset_manager), GFP_KERNEL);
100 if (!vma_offset_manager) {
101 DRM_ERROR("out of memory\n");
102 return -ENOMEM;
103 }
104
105 dev->vma_offset_manager = vma_offset_manager;
106 drm_vma_offset_manager_init(vma_offset_manager,
107 DRM_FILE_PAGE_OFFSET_START,
108 DRM_FILE_PAGE_OFFSET_SIZE);
109
110 return 0;
111}
112
113void
114drm_gem_destroy(struct drm_device *dev)
115{
116
117 drm_vma_offset_manager_destroy(dev->vma_offset_manager);
118 kfree(dev->vma_offset_manager);
119 dev->vma_offset_manager = NULL;
120}
121
122/**
123 * drm_gem_object_init - initialize an allocated shmem-backed GEM object
124 * @dev: drm_device the object should be initialized for
125 * @obj: drm_gem_object to initialize
126 * @size: object size
127 *
128 * Initialize an already allocated GEM object of the specified size with
129 * shmfs backing store.
130 */
131int drm_gem_object_init(struct drm_device *dev,
132 struct drm_gem_object *obj, size_t size)
133{
134 struct file *filp;
135
136 drm_gem_private_object_init(dev, obj, size);
137
138 filp = shmem_file_setup("drm mm object", size, VM_NORESERVE);
139 if (IS_ERR(filp))
140 return PTR_ERR(filp);
141
142 obj->filp = filp;
143
144 return 0;
145}
146EXPORT_SYMBOL(drm_gem_object_init);
147
148/**
149 * drm_gem_object_init - initialize an allocated private GEM object
150 * @dev: drm_device the object should be initialized for
151 * @obj: drm_gem_object to initialize
152 * @size: object size
153 *
154 * Initialize an already allocated GEM object of the specified size with
155 * no GEM provided backing store. Instead the caller is responsible for
156 * backing the object and handling it.
157 */
158void drm_gem_private_object_init(struct drm_device *dev,
159 struct drm_gem_object *obj, size_t size)
160{
161 BUG_ON((size & (PAGE_SIZE - 1)) != 0);
162
163 obj->dev = dev;
164 obj->filp = NULL;
165
166 kref_init(&obj->refcount);
167 obj->handle_count = 0;
168 obj->size = size;
169 drm_vma_node_reset(&obj->vma_node);
170}
171EXPORT_SYMBOL(drm_gem_private_object_init);
172
173static void
174drm_gem_remove_prime_handles(struct drm_gem_object *obj, struct drm_file *filp)
175{
176 /*
177 * Note: obj->dma_buf can't disappear as long as we still hold a
178 * handle reference in obj->handle_count.
179 */
180 mutex_lock(&filp->prime.lock);
181 if (obj->dma_buf) {
182 drm_prime_remove_buf_handle_locked(&filp->prime,
183 obj->dma_buf);
184 }
185 mutex_unlock(&filp->prime.lock);
186}
187
188/**
189 * drm_gem_object_free - release resources bound to userspace handles
190 * @obj: GEM object to clean up.
191 *
192 * Called after the last handle to the object has been closed
193 *
194 * Removes any name for the object. Note that this must be
195 * called before drm_gem_object_free or we'll be touching
196 * freed memory
197 */
198static void drm_gem_object_handle_free(struct drm_gem_object *obj)
199{
200 struct drm_device *dev = obj->dev;
201
202 /* Remove any name for this object */
203 if (obj->name) {
204 idr_remove(&dev->object_name_idr, obj->name);
205 obj->name = 0;
206 }
207}
208
209static void drm_gem_object_exported_dma_buf_free(struct drm_gem_object *obj)
210{
211 /* Unbreak the reference cycle if we have an exported dma_buf. */
212 if (obj->dma_buf) {
213 dma_buf_put(obj->dma_buf);
214 obj->dma_buf = NULL;
215 }
216}
217
218static void
219drm_gem_object_handle_unreference_unlocked(struct drm_gem_object *obj)
220{
221 if (WARN_ON(obj->handle_count == 0))
222 return;
223
224 /*
225 * Must bump handle count first as this may be the last
226 * ref, in which case the object would disappear before we
227 * checked for a name
228 */
229
230 mutex_lock(&obj->dev->object_name_lock);
231 if (--obj->handle_count == 0) {
232 drm_gem_object_handle_free(obj);
233 drm_gem_object_exported_dma_buf_free(obj);
234 }
235 mutex_unlock(&obj->dev->object_name_lock);
236
237 drm_gem_object_unreference_unlocked(obj);
238}
239
240/**
241 * drm_gem_handle_delete - deletes the given file-private handle
242 * @filp: drm file-private structure to use for the handle look up
243 * @handle: userspace handle to delete
244 *
245 * Removes the GEM handle from the @filp lookup table and if this is the last
246 * handle also cleans up linked resources like GEM names.
247 */
248int
249drm_gem_handle_delete(struct drm_file *filp, u32 handle)
250{
251 struct drm_device *dev;
252 struct drm_gem_object *obj;
253
254 /* This is gross. The idr system doesn't let us try a delete and
255 * return an error code. It just spews if you fail at deleting.
256 * So, we have to grab a lock around finding the object and then
257 * doing the delete on it and dropping the refcount, or the user
258 * could race us to double-decrement the refcount and cause a
259 * use-after-free later. Given the frequency of our handle lookups,
260 * we may want to use ida for number allocation and a hash table
261 * for the pointers, anyway.
262 */
263 spin_lock(&filp->table_lock);
264
265 /* Check if we currently have a reference on the object */
266 obj = idr_find(&filp->object_idr, handle);
267 if (obj == NULL) {
268 spin_unlock(&filp->table_lock);
269 return -EINVAL;
270 }
271 dev = obj->dev;
272
273 /* Release reference and decrement refcount. */
274 idr_remove(&filp->object_idr, handle);
275 spin_unlock(&filp->table_lock);
276
277 if (drm_core_check_feature(dev, DRIVER_PRIME))
278 drm_gem_remove_prime_handles(obj, filp);
279 drm_vma_node_revoke(&obj->vma_node, filp->filp);
280
281 if (dev->driver->gem_close_object)
282 dev->driver->gem_close_object(obj, filp);
283 drm_gem_object_handle_unreference_unlocked(obj);
284
285 return 0;
286}
287EXPORT_SYMBOL(drm_gem_handle_delete);
288
289/**
290 * drm_gem_dumb_destroy - dumb fb callback helper for gem based drivers
291 * @file: drm file-private structure to remove the dumb handle from
292 * @dev: corresponding drm_device
293 * @handle: the dumb handle to remove
294 *
295 * This implements the ->dumb_destroy kms driver callback for drivers which use
296 * gem to manage their backing storage.
297 */
298int drm_gem_dumb_destroy(struct drm_file *file,
299 struct drm_device *dev,
300 uint32_t handle)
301{
302 return drm_gem_handle_delete(file, handle);
303}
304EXPORT_SYMBOL(drm_gem_dumb_destroy);
305
306/**
307 * drm_gem_handle_create_tail - internal functions to create a handle
308 * @file_priv: drm file-private structure to register the handle for
309 * @obj: object to register
310 * @handlep: pionter to return the created handle to the caller
311 *
312 * This expects the dev->object_name_lock to be held already and will drop it
313 * before returning. Used to avoid races in establishing new handles when
314 * importing an object from either an flink name or a dma-buf.
315 */
316int
317drm_gem_handle_create_tail(struct drm_file *file_priv,
318 struct drm_gem_object *obj,
319 u32 *handlep)
320{
321 struct drm_device *dev = obj->dev;
322 int ret;
323
324 WARN_ON(!mutex_is_locked(&dev->object_name_lock));
325
326 /*
327 * Get the user-visible handle using idr. Preload and perform
328 * allocation under our spinlock.
329 */
330 idr_preload(GFP_KERNEL);
331 spin_lock(&file_priv->table_lock);
332
333 ret = idr_alloc(&file_priv->object_idr, obj, 1, 0, GFP_NOWAIT);
334 drm_gem_object_reference(obj);
335 obj->handle_count++;
336 spin_unlock(&file_priv->table_lock);
337 idr_preload_end();
338 mutex_unlock(&dev->object_name_lock);
339 if (ret < 0) {
340 drm_gem_object_handle_unreference_unlocked(obj);
341 return ret;
342 }
343 *handlep = ret;
344
345 ret = drm_vma_node_allow(&obj->vma_node, file_priv->filp);
346 if (ret) {
347 drm_gem_handle_delete(file_priv, *handlep);
348 return ret;
349 }
350
351 if (dev->driver->gem_open_object) {
352 ret = dev->driver->gem_open_object(obj, file_priv);
353 if (ret) {
354 drm_gem_handle_delete(file_priv, *handlep);
355 return ret;
356 }
357 }
358
359 return 0;
360}
361
362/**
363 * gem_handle_create - create a gem handle for an object
364 * @file_priv: drm file-private structure to register the handle for
365 * @obj: object to register
366 * @handlep: pionter to return the created handle to the caller
367 *
368 * Create a handle for this object. This adds a handle reference
369 * to the object, which includes a regular reference count. Callers
370 * will likely want to dereference the object afterwards.
371 */
372int
373drm_gem_handle_create(struct drm_file *file_priv,
374 struct drm_gem_object *obj,
375 u32 *handlep)
376{
377 mutex_lock(&obj->dev->object_name_lock);
378
379 return drm_gem_handle_create_tail(file_priv, obj, handlep);
380}
381EXPORT_SYMBOL(drm_gem_handle_create);
382
383
384/**
385 * drm_gem_free_mmap_offset - release a fake mmap offset for an object
386 * @obj: obj in question
387 *
388 * This routine frees fake offsets allocated by drm_gem_create_mmap_offset().
389 */
390void
391drm_gem_free_mmap_offset(struct drm_gem_object *obj)
392{
393 struct drm_device *dev = obj->dev;
394
395 drm_vma_offset_remove(dev->vma_offset_manager, &obj->vma_node);
396}
397EXPORT_SYMBOL(drm_gem_free_mmap_offset);
398
399/**
400 * drm_gem_create_mmap_offset_size - create a fake mmap offset for an object
401 * @obj: obj in question
402 * @size: the virtual size
403 *
404 * GEM memory mapping works by handing back to userspace a fake mmap offset
405 * it can use in a subsequent mmap(2) call. The DRM core code then looks
406 * up the object based on the offset and sets up the various memory mapping
407 * structures.
408 *
409 * This routine allocates and attaches a fake offset for @obj, in cases where
410 * the virtual size differs from the physical size (ie. obj->size). Otherwise
411 * just use drm_gem_create_mmap_offset().
412 */
413int
414drm_gem_create_mmap_offset_size(struct drm_gem_object *obj, size_t size)
415{
416 struct drm_device *dev = obj->dev;
417
418 return drm_vma_offset_add(dev->vma_offset_manager, &obj->vma_node,
419 size / PAGE_SIZE);
420}
421EXPORT_SYMBOL(drm_gem_create_mmap_offset_size);
422
423/**
424 * drm_gem_create_mmap_offset - create a fake mmap offset for an object
425 * @obj: obj in question
426 *
427 * GEM memory mapping works by handing back to userspace a fake mmap offset
428 * it can use in a subsequent mmap(2) call. The DRM core code then looks
429 * up the object based on the offset and sets up the various memory mapping
430 * structures.
431 *
432 * This routine allocates and attaches a fake offset for @obj.
433 */
434int drm_gem_create_mmap_offset(struct drm_gem_object *obj)
435{
436 return drm_gem_create_mmap_offset_size(obj, obj->size);
437}
438EXPORT_SYMBOL(drm_gem_create_mmap_offset);
439
440/**
441 * drm_gem_get_pages - helper to allocate backing pages for a GEM object
442 * from shmem
443 * @obj: obj in question
444 * @gfpmask: gfp mask of requested pages
445 */
446struct page **drm_gem_get_pages(struct drm_gem_object *obj, gfp_t gfpmask)
447{
448 struct inode *inode;
449 struct address_space *mapping;
450 struct page *p, **pages;
451 int i, npages;
452
453 /* This is the shared memory object that backs the GEM resource */
454 inode = file_inode(obj->filp);
455 mapping = inode->i_mapping;
456
457 /* We already BUG_ON() for non-page-aligned sizes in
458 * drm_gem_object_init(), so we should never hit this unless
459 * driver author is doing something really wrong:
460 */
461 WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0);
462
463 npages = obj->size >> PAGE_SHIFT;
464
465 pages = drm_malloc_ab(npages, sizeof(struct page *));
466 if (pages == NULL)
467 return ERR_PTR(-ENOMEM);
468
469 gfpmask |= mapping_gfp_mask(mapping);
470
471 for (i = 0; i < npages; i++) {
472 p = shmem_read_mapping_page_gfp(mapping, i, gfpmask);
473 if (IS_ERR(p))
474 goto fail;
475 pages[i] = p;
476
477 /* There is a hypothetical issue w/ drivers that require
478 * buffer memory in the low 4GB.. if the pages are un-
479 * pinned, and swapped out, they can end up swapped back
480 * in above 4GB. If pages are already in memory, then
481 * shmem_read_mapping_page_gfp will ignore the gfpmask,
482 * even if the already in-memory page disobeys the mask.
483 *
484 * It is only a theoretical issue today, because none of
485 * the devices with this limitation can be populated with
486 * enough memory to trigger the issue. But this BUG_ON()
487 * is here as a reminder in case the problem with
488 * shmem_read_mapping_page_gfp() isn't solved by the time
489 * it does become a real issue.
490 *
491 * See this thread: http://lkml.org/lkml/2011/7/11/238
492 */
493 BUG_ON((gfpmask & __GFP_DMA32) &&
494 (page_to_pfn(p) >= 0x00100000UL));
495 }
496
497 return pages;
498
499fail:
500 while (i--)
501 page_cache_release(pages[i]);
502
503 drm_free_large(pages);
504 return ERR_CAST(p);
505}
506EXPORT_SYMBOL(drm_gem_get_pages);
507
508/**
509 * drm_gem_put_pages - helper to free backing pages for a GEM object
510 * @obj: obj in question
511 * @pages: pages to free
512 * @dirty: if true, pages will be marked as dirty
513 * @accessed: if true, the pages will be marked as accessed
514 */
515void drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages,
516 bool dirty, bool accessed)
517{
518 int i, npages;
519
520 /* We already BUG_ON() for non-page-aligned sizes in
521 * drm_gem_object_init(), so we should never hit this unless
522 * driver author is doing something really wrong:
523 */
524 WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0);
525
526 npages = obj->size >> PAGE_SHIFT;
527
528 for (i = 0; i < npages; i++) {
529 if (dirty)
530 set_page_dirty(pages[i]);
531
532 if (accessed)
533 mark_page_accessed(pages[i]);
534
535 /* Undo the reference we took when populating the table */
536 page_cache_release(pages[i]);
537 }
538
539 drm_free_large(pages);
540}
541EXPORT_SYMBOL(drm_gem_put_pages);
542
543/** Returns a reference to the object named by the handle. */
544struct drm_gem_object *
545drm_gem_object_lookup(struct drm_device *dev, struct drm_file *filp,
546 u32 handle)
547{
548 struct drm_gem_object *obj;
549
550 spin_lock(&filp->table_lock);
551
552 /* Check if we currently have a reference on the object */
553 obj = idr_find(&filp->object_idr, handle);
554 if (obj == NULL) {
555 spin_unlock(&filp->table_lock);
556 return NULL;
557 }
558
559 drm_gem_object_reference(obj);
560
561 spin_unlock(&filp->table_lock);
562
563 return obj;
564}
565EXPORT_SYMBOL(drm_gem_object_lookup);
566
567/**
568 * drm_gem_close_ioctl - implementation of the GEM_CLOSE ioctl
569 * @dev: drm_device
570 * @data: ioctl data
571 * @file_priv: drm file-private structure
572 *
573 * Releases the handle to an mm object.
574 */
575int
576drm_gem_close_ioctl(struct drm_device *dev, void *data,
577 struct drm_file *file_priv)
578{
579 struct drm_gem_close *args = data;
580 int ret;
581
582 if (!(dev->driver->driver_features & DRIVER_GEM))
583 return -ENODEV;
584
585 ret = drm_gem_handle_delete(file_priv, args->handle);
586
587 return ret;
588}
589
590/**
591 * drm_gem_flink_ioctl - implementation of the GEM_FLINK ioctl
592 * @dev: drm_device
593 * @data: ioctl data
594 * @file_priv: drm file-private structure
595 *
596 * Create a global name for an object, returning the name.
597 *
598 * Note that the name does not hold a reference; when the object
599 * is freed, the name goes away.
600 */
601int
602drm_gem_flink_ioctl(struct drm_device *dev, void *data,
603 struct drm_file *file_priv)
604{
605 struct drm_gem_flink *args = data;
606 struct drm_gem_object *obj;
607 int ret;
608
609 if (!(dev->driver->driver_features & DRIVER_GEM))
610 return -ENODEV;
611
612 obj = drm_gem_object_lookup(dev, file_priv, args->handle);
613 if (obj == NULL)
614 return -ENOENT;
615
616 mutex_lock(&dev->object_name_lock);
617 idr_preload(GFP_KERNEL);
618 /* prevent races with concurrent gem_close. */
619 if (obj->handle_count == 0) {
620 ret = -ENOENT;
621 goto err;
622 }
623
624 if (!obj->name) {
625 ret = idr_alloc(&dev->object_name_idr, obj, 1, 0, GFP_NOWAIT);
626 if (ret < 0)
627 goto err;
628
629 obj->name = ret;
630 }
631
632 args->name = (uint64_t) obj->name;
633 ret = 0;
634
635err:
636 idr_preload_end();
637 mutex_unlock(&dev->object_name_lock);
638 drm_gem_object_unreference_unlocked(obj);
639 return ret;
640}
641
642/**
643 * drm_gem_open - implementation of the GEM_OPEN ioctl
644 * @dev: drm_device
645 * @data: ioctl data
646 * @file_priv: drm file-private structure
647 *
648 * Open an object using the global name, returning a handle and the size.
649 *
650 * This handle (of course) holds a reference to the object, so the object
651 * will not go away until the handle is deleted.
652 */
653int
654drm_gem_open_ioctl(struct drm_device *dev, void *data,
655 struct drm_file *file_priv)
656{
657 struct drm_gem_open *args = data;
658 struct drm_gem_object *obj;
659 int ret;
660 u32 handle;
661
662 if (!(dev->driver->driver_features & DRIVER_GEM))
663 return -ENODEV;
664
665 mutex_lock(&dev->object_name_lock);
666 obj = idr_find(&dev->object_name_idr, (int) args->name);
667 if (obj) {
668 drm_gem_object_reference(obj);
669 } else {
670 mutex_unlock(&dev->object_name_lock);
671 return -ENOENT;
672 }
673
674 /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */
675 ret = drm_gem_handle_create_tail(file_priv, obj, &handle);
676 drm_gem_object_unreference_unlocked(obj);
677 if (ret)
678 return ret;
679
680 args->handle = handle;
681 args->size = obj->size;
682
683 return 0;
684}
685
686/**
687 * gem_gem_open - initalizes GEM file-private structures at devnode open time
688 * @dev: drm_device which is being opened by userspace
689 * @file_private: drm file-private structure to set up
690 *
691 * Called at device open time, sets up the structure for handling refcounting
692 * of mm objects.
693 */
694void
695drm_gem_open(struct drm_device *dev, struct drm_file *file_private)
696{
697 idr_init(&file_private->object_idr);
698 spin_lock_init(&file_private->table_lock);
699}
700
701/*
702 * Called at device close to release the file's
703 * handle references on objects.
704 */
705static int
706drm_gem_object_release_handle(int id, void *ptr, void *data)
707{
708 struct drm_file *file_priv = data;
709 struct drm_gem_object *obj = ptr;
710 struct drm_device *dev = obj->dev;
711
712 if (drm_core_check_feature(dev, DRIVER_PRIME))
713 drm_gem_remove_prime_handles(obj, file_priv);
714 drm_vma_node_revoke(&obj->vma_node, file_priv->filp);
715
716 if (dev->driver->gem_close_object)
717 dev->driver->gem_close_object(obj, file_priv);
718
719 drm_gem_object_handle_unreference_unlocked(obj);
720
721 return 0;
722}
723
724/**
725 * drm_gem_release - release file-private GEM resources
726 * @dev: drm_device which is being closed by userspace
727 * @file_private: drm file-private structure to clean up
728 *
729 * Called at close time when the filp is going away.
730 *
731 * Releases any remaining references on objects by this filp.
732 */
733void
734drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
735{
736 idr_for_each(&file_private->object_idr,
737 &drm_gem_object_release_handle, file_private);
738 idr_destroy(&file_private->object_idr);
739}
740
741void
742drm_gem_object_release(struct drm_gem_object *obj)
743{
744 WARN_ON(obj->dma_buf);
745
746 if (obj->filp)
747 fput(obj->filp);
748
749 drm_gem_free_mmap_offset(obj);
750}
751EXPORT_SYMBOL(drm_gem_object_release);
752
753/**
754 * drm_gem_object_free - free a GEM object
755 * @kref: kref of the object to free
756 *
757 * Called after the last reference to the object has been lost.
758 * Must be called holding struct_ mutex
759 *
760 * Frees the object
761 */
762void
763drm_gem_object_free(struct kref *kref)
764{
765 struct drm_gem_object *obj = (struct drm_gem_object *) kref;
766 struct drm_device *dev = obj->dev;
767
768 BUG_ON(!mutex_is_locked(&dev->struct_mutex));
769
770 if (dev->driver->gem_free_object != NULL)
771 dev->driver->gem_free_object(obj);
772}
773EXPORT_SYMBOL(drm_gem_object_free);
774
775void drm_gem_vm_open(struct vm_area_struct *vma)
776{
777 struct drm_gem_object *obj = vma->vm_private_data;
778
779 drm_gem_object_reference(obj);
780
781 mutex_lock(&obj->dev->struct_mutex);
782 drm_vm_open_locked(obj->dev, vma);
783 mutex_unlock(&obj->dev->struct_mutex);
784}
785EXPORT_SYMBOL(drm_gem_vm_open);
786
787void drm_gem_vm_close(struct vm_area_struct *vma)
788{
789 struct drm_gem_object *obj = vma->vm_private_data;
790 struct drm_device *dev = obj->dev;
791
792 mutex_lock(&dev->struct_mutex);
793 drm_vm_close_locked(obj->dev, vma);
794 drm_gem_object_unreference(obj);
795 mutex_unlock(&dev->struct_mutex);
796}
797EXPORT_SYMBOL(drm_gem_vm_close);
798
799/**
800 * drm_gem_mmap_obj - memory map a GEM object
801 * @obj: the GEM object to map
802 * @obj_size: the object size to be mapped, in bytes
803 * @vma: VMA for the area to be mapped
804 *
805 * Set up the VMA to prepare mapping of the GEM object using the gem_vm_ops
806 * provided by the driver. Depending on their requirements, drivers can either
807 * provide a fault handler in their gem_vm_ops (in which case any accesses to
808 * the object will be trapped, to perform migration, GTT binding, surface
809 * register allocation, or performance monitoring), or mmap the buffer memory
810 * synchronously after calling drm_gem_mmap_obj.
811 *
812 * This function is mainly intended to implement the DMABUF mmap operation, when
813 * the GEM object is not looked up based on its fake offset. To implement the
814 * DRM mmap operation, drivers should use the drm_gem_mmap() function.
815 *
816 * drm_gem_mmap_obj() assumes the user is granted access to the buffer while
817 * drm_gem_mmap() prevents unprivileged users from mapping random objects. So
818 * callers must verify access restrictions before calling this helper.
819 *
820 * NOTE: This function has to be protected with dev->struct_mutex
821 *
822 * Return 0 or success or -EINVAL if the object size is smaller than the VMA
823 * size, or if no gem_vm_ops are provided.
824 */
825int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
826 struct vm_area_struct *vma)
827{
828 struct drm_device *dev = obj->dev;
829
830 lockdep_assert_held(&dev->struct_mutex);
831
832 /* Check for valid size. */
833 if (obj_size < vma->vm_end - vma->vm_start)
834 return -EINVAL;
835
836 if (!dev->driver->gem_vm_ops)
837 return -EINVAL;
838
839 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
840 vma->vm_ops = dev->driver->gem_vm_ops;
841 vma->vm_private_data = obj;
842 vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
843
844 /* Take a ref for this mapping of the object, so that the fault
845 * handler can dereference the mmap offset's pointer to the object.
846 * This reference is cleaned up by the corresponding vm_close
847 * (which should happen whether the vma was created by this call, or
848 * by a vm_open due to mremap or partial unmap or whatever).
849 */
850 drm_gem_object_reference(obj);
851
852 drm_vm_open_locked(dev, vma);
853 return 0;
854}
855EXPORT_SYMBOL(drm_gem_mmap_obj);
856
857/**
858 * drm_gem_mmap - memory map routine for GEM objects
859 * @filp: DRM file pointer
860 * @vma: VMA for the area to be mapped
861 *
862 * If a driver supports GEM object mapping, mmap calls on the DRM file
863 * descriptor will end up here.
864 *
865 * Look up the GEM object based on the offset passed in (vma->vm_pgoff will
866 * contain the fake offset we created when the GTT map ioctl was called on
867 * the object) and map it with a call to drm_gem_mmap_obj().
868 *
869 * If the caller is not granted access to the buffer object, the mmap will fail
870 * with EACCES. Please see the vma manager for more information.
871 */
872int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
873{
874 struct drm_file *priv = filp->private_data;
875 struct drm_device *dev = priv->minor->dev;
876 struct drm_gem_object *obj;
877 struct drm_vma_offset_node *node;
878 int ret;
879
880 if (drm_device_is_unplugged(dev))
881 return -ENODEV;
882
883 mutex_lock(&dev->struct_mutex);
884
885 node = drm_vma_offset_exact_lookup(dev->vma_offset_manager,
886 vma->vm_pgoff,
887 vma_pages(vma));
888 if (!node) {
889 mutex_unlock(&dev->struct_mutex);
890 return drm_mmap(filp, vma);
891 } else if (!drm_vma_node_is_allowed(node, filp)) {
892 mutex_unlock(&dev->struct_mutex);
893 return -EACCES;
894 }
895
896 obj = container_of(node, struct drm_gem_object, vma_node);
897 ret = drm_gem_mmap_obj(obj, drm_vma_node_size(node) << PAGE_SHIFT, vma);
898
899 mutex_unlock(&dev->struct_mutex);
900
901 return ret;
902}
903EXPORT_SYMBOL(drm_gem_mmap);
1/*
2 * Copyright © 2008 Intel Corporation
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 *
23 * Authors:
24 * Eric Anholt <eric@anholt.net>
25 *
26 */
27
28#include <linux/types.h>
29#include <linux/slab.h>
30#include <linux/mm.h>
31#include <linux/uaccess.h>
32#include <linux/fs.h>
33#include <linux/file.h>
34#include <linux/module.h>
35#include <linux/mman.h>
36#include <linux/pagemap.h>
37#include <linux/shmem_fs.h>
38#include <linux/dma-buf.h>
39#include <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}