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1/*
2 * Copyright © 2008 Intel Corporation
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 *
23 * Authors:
24 * Eric Anholt <eric@anholt.net>
25 *
26 */
27
28#include <linux/types.h>
29#include <linux/slab.h>
30#include <linux/mm.h>
31#include <linux/uaccess.h>
32#include <linux/fs.h>
33#include <linux/file.h>
34#include <linux/module.h>
35#include <linux/mman.h>
36#include <linux/pagemap.h>
37#include <linux/shmem_fs.h>
38#include <linux/dma-buf.h>
39#include <drm/drmP.h>
40#include <drm/drm_vma_manager.h>
41#include <drm/drm_gem.h>
42#include "drm_internal.h"
43
44/** @file drm_gem.c
45 *
46 * This file provides some of the base ioctls and library routines for
47 * the graphics memory manager implemented by each device driver.
48 *
49 * Because various devices have different requirements in terms of
50 * synchronization and migration strategies, implementing that is left up to
51 * the driver, and all that the general API provides should be generic --
52 * allocating objects, reading/writing data with the cpu, freeing objects.
53 * Even there, platform-dependent optimizations for reading/writing data with
54 * the CPU mean we'll likely hook those out to driver-specific calls. However,
55 * the DRI2 implementation wants to have at least allocate/mmap be generic.
56 *
57 * The goal was to have swap-backed object allocation managed through
58 * struct file. However, file descriptors as handles to a struct file have
59 * two major failings:
60 * - Process limits prevent more than 1024 or so being used at a time by
61 * default.
62 * - Inability to allocate high fds will aggravate the X Server's select()
63 * handling, and likely that of many GL client applications as well.
64 *
65 * This led to a plan of using our own integer IDs (called handles, following
66 * DRM terminology) to mimic fds, and implement the fd syscalls we need as
67 * ioctls. The objects themselves will still include the struct file so
68 * that we can transition to fds if the required kernel infrastructure shows
69 * up at a later date, and as our interface with shmfs for memory allocation.
70 */
71
72/*
73 * We make up offsets for buffer objects so we can recognize them at
74 * mmap time.
75 */
76
77/* pgoff in mmap is an unsigned long, so we need to make sure that
78 * the faked up offset will fit
79 */
80
81#if BITS_PER_LONG == 64
82#define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFFUL >> PAGE_SHIFT) + 1)
83#define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFFUL >> PAGE_SHIFT) * 16)
84#else
85#define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFUL >> PAGE_SHIFT) + 1)
86#define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFUL >> PAGE_SHIFT) * 16)
87#endif
88
89/**
90 * drm_gem_init - Initialize the GEM device fields
91 * @dev: drm_devic structure to initialize
92 */
93int
94drm_gem_init(struct drm_device *dev)
95{
96 struct drm_vma_offset_manager *vma_offset_manager;
97
98 mutex_init(&dev->object_name_lock);
99 idr_init(&dev->object_name_idr);
100
101 vma_offset_manager = kzalloc(sizeof(*vma_offset_manager), GFP_KERNEL);
102 if (!vma_offset_manager) {
103 DRM_ERROR("out of memory\n");
104 return -ENOMEM;
105 }
106
107 dev->vma_offset_manager = vma_offset_manager;
108 drm_vma_offset_manager_init(vma_offset_manager,
109 DRM_FILE_PAGE_OFFSET_START,
110 DRM_FILE_PAGE_OFFSET_SIZE);
111
112 return 0;
113}
114
115void
116drm_gem_destroy(struct drm_device *dev)
117{
118
119 drm_vma_offset_manager_destroy(dev->vma_offset_manager);
120 kfree(dev->vma_offset_manager);
121 dev->vma_offset_manager = NULL;
122}
123
124/**
125 * drm_gem_object_init - initialize an allocated shmem-backed GEM object
126 * @dev: drm_device the object should be initialized for
127 * @obj: drm_gem_object to initialize
128 * @size: object size
129 *
130 * Initialize an already allocated GEM object of the specified size with
131 * shmfs backing store.
132 */
133int drm_gem_object_init(struct drm_device *dev,
134 struct drm_gem_object *obj, size_t size)
135{
136 struct file *filp;
137
138 drm_gem_private_object_init(dev, obj, size);
139
140 filp = shmem_file_setup("drm mm object", size, VM_NORESERVE);
141 if (IS_ERR(filp))
142 return PTR_ERR(filp);
143
144 obj->filp = filp;
145
146 return 0;
147}
148EXPORT_SYMBOL(drm_gem_object_init);
149
150/**
151 * drm_gem_private_object_init - initialize an allocated private GEM object
152 * @dev: drm_device the object should be initialized for
153 * @obj: drm_gem_object to initialize
154 * @size: object size
155 *
156 * Initialize an already allocated GEM object of the specified size with
157 * no GEM provided backing store. Instead the caller is responsible for
158 * backing the object and handling it.
159 */
160void drm_gem_private_object_init(struct drm_device *dev,
161 struct drm_gem_object *obj, size_t size)
162{
163 BUG_ON((size & (PAGE_SIZE - 1)) != 0);
164
165 obj->dev = dev;
166 obj->filp = NULL;
167
168 kref_init(&obj->refcount);
169 obj->handle_count = 0;
170 obj->size = size;
171 drm_vma_node_reset(&obj->vma_node);
172}
173EXPORT_SYMBOL(drm_gem_private_object_init);
174
175static void
176drm_gem_remove_prime_handles(struct drm_gem_object *obj, struct drm_file *filp)
177{
178 /*
179 * Note: obj->dma_buf can't disappear as long as we still hold a
180 * handle reference in obj->handle_count.
181 */
182 mutex_lock(&filp->prime.lock);
183 if (obj->dma_buf) {
184 drm_prime_remove_buf_handle_locked(&filp->prime,
185 obj->dma_buf);
186 }
187 mutex_unlock(&filp->prime.lock);
188}
189
190/**
191 * drm_gem_object_handle_free - release resources bound to userspace handles
192 * @obj: GEM object to clean up.
193 *
194 * Called after the last handle to the object has been closed
195 *
196 * Removes any name for the object. Note that this must be
197 * called before drm_gem_object_free or we'll be touching
198 * freed memory
199 */
200static void drm_gem_object_handle_free(struct drm_gem_object *obj)
201{
202 struct drm_device *dev = obj->dev;
203
204 /* Remove any name for this object */
205 if (obj->name) {
206 idr_remove(&dev->object_name_idr, obj->name);
207 obj->name = 0;
208 }
209}
210
211static void drm_gem_object_exported_dma_buf_free(struct drm_gem_object *obj)
212{
213 /* Unbreak the reference cycle if we have an exported dma_buf. */
214 if (obj->dma_buf) {
215 dma_buf_put(obj->dma_buf);
216 obj->dma_buf = NULL;
217 }
218}
219
220static void
221drm_gem_object_handle_unreference_unlocked(struct drm_gem_object *obj)
222{
223 struct drm_device *dev = obj->dev;
224 bool final = false;
225
226 if (WARN_ON(obj->handle_count == 0))
227 return;
228
229 /*
230 * Must bump handle count first as this may be the last
231 * ref, in which case the object would disappear before we
232 * checked for a name
233 */
234
235 mutex_lock(&dev->object_name_lock);
236 if (--obj->handle_count == 0) {
237 drm_gem_object_handle_free(obj);
238 drm_gem_object_exported_dma_buf_free(obj);
239 final = true;
240 }
241 mutex_unlock(&dev->object_name_lock);
242
243 if (final)
244 drm_gem_object_unreference_unlocked(obj);
245}
246
247/*
248 * Called at device or object close to release the file's
249 * handle references on objects.
250 */
251static int
252drm_gem_object_release_handle(int id, void *ptr, void *data)
253{
254 struct drm_file *file_priv = data;
255 struct drm_gem_object *obj = ptr;
256 struct drm_device *dev = obj->dev;
257
258 if (drm_core_check_feature(dev, DRIVER_PRIME))
259 drm_gem_remove_prime_handles(obj, file_priv);
260 drm_vma_node_revoke(&obj->vma_node, file_priv->filp);
261
262 if (dev->driver->gem_close_object)
263 dev->driver->gem_close_object(obj, file_priv);
264
265 drm_gem_object_handle_unreference_unlocked(obj);
266
267 return 0;
268}
269
270/**
271 * drm_gem_handle_delete - deletes the given file-private handle
272 * @filp: drm file-private structure to use for the handle look up
273 * @handle: userspace handle to delete
274 *
275 * Removes the GEM handle from the @filp lookup table which has been added with
276 * drm_gem_handle_create(). If this is the last handle also cleans up linked
277 * resources like GEM names.
278 */
279int
280drm_gem_handle_delete(struct drm_file *filp, u32 handle)
281{
282 struct drm_device *dev;
283 struct drm_gem_object *obj;
284
285 /* This is gross. The idr system doesn't let us try a delete and
286 * return an error code. It just spews if you fail at deleting.
287 * So, we have to grab a lock around finding the object and then
288 * doing the delete on it and dropping the refcount, or the user
289 * could race us to double-decrement the refcount and cause a
290 * use-after-free later. Given the frequency of our handle lookups,
291 * we may want to use ida for number allocation and a hash table
292 * for the pointers, anyway.
293 */
294 spin_lock(&filp->table_lock);
295
296 /* Check if we currently have a reference on the object */
297 obj = idr_find(&filp->object_idr, handle);
298 if (obj == NULL) {
299 spin_unlock(&filp->table_lock);
300 return -EINVAL;
301 }
302 dev = obj->dev;
303
304 /* Release reference and decrement refcount. */
305 idr_remove(&filp->object_idr, handle);
306 spin_unlock(&filp->table_lock);
307
308 drm_gem_object_release_handle(handle, obj, filp);
309 return 0;
310}
311EXPORT_SYMBOL(drm_gem_handle_delete);
312
313/**
314 * drm_gem_dumb_destroy - dumb fb callback helper for gem based drivers
315 * @file: drm file-private structure to remove the dumb handle from
316 * @dev: corresponding drm_device
317 * @handle: the dumb handle to remove
318 *
319 * This implements the ->dumb_destroy kms driver callback for drivers which use
320 * gem to manage their backing storage.
321 */
322int drm_gem_dumb_destroy(struct drm_file *file,
323 struct drm_device *dev,
324 uint32_t handle)
325{
326 return drm_gem_handle_delete(file, handle);
327}
328EXPORT_SYMBOL(drm_gem_dumb_destroy);
329
330/**
331 * drm_gem_handle_create_tail - internal functions to create a handle
332 * @file_priv: drm file-private structure to register the handle for
333 * @obj: object to register
334 * @handlep: pointer to return the created handle to the caller
335 *
336 * This expects the dev->object_name_lock to be held already and will drop it
337 * before returning. Used to avoid races in establishing new handles when
338 * importing an object from either an flink name or a dma-buf.
339 *
340 * Handles must be release again through drm_gem_handle_delete(). This is done
341 * when userspace closes @file_priv for all attached handles, or through the
342 * GEM_CLOSE ioctl for individual handles.
343 */
344int
345drm_gem_handle_create_tail(struct drm_file *file_priv,
346 struct drm_gem_object *obj,
347 u32 *handlep)
348{
349 struct drm_device *dev = obj->dev;
350 u32 handle;
351 int ret;
352
353 WARN_ON(!mutex_is_locked(&dev->object_name_lock));
354 if (obj->handle_count++ == 0)
355 drm_gem_object_reference(obj);
356
357 /*
358 * Get the user-visible handle using idr. Preload and perform
359 * allocation under our spinlock.
360 */
361 idr_preload(GFP_KERNEL);
362 spin_lock(&file_priv->table_lock);
363
364 ret = idr_alloc(&file_priv->object_idr, obj, 1, 0, GFP_NOWAIT);
365
366 spin_unlock(&file_priv->table_lock);
367 idr_preload_end();
368
369 mutex_unlock(&dev->object_name_lock);
370 if (ret < 0)
371 goto err_unref;
372
373 handle = ret;
374
375 ret = drm_vma_node_allow(&obj->vma_node, file_priv->filp);
376 if (ret)
377 goto err_remove;
378
379 if (dev->driver->gem_open_object) {
380 ret = dev->driver->gem_open_object(obj, file_priv);
381 if (ret)
382 goto err_revoke;
383 }
384
385 *handlep = handle;
386 return 0;
387
388err_revoke:
389 drm_vma_node_revoke(&obj->vma_node, file_priv->filp);
390err_remove:
391 spin_lock(&file_priv->table_lock);
392 idr_remove(&file_priv->object_idr, handle);
393 spin_unlock(&file_priv->table_lock);
394err_unref:
395 drm_gem_object_handle_unreference_unlocked(obj);
396 return ret;
397}
398
399/**
400 * drm_gem_handle_create - create a gem handle for an object
401 * @file_priv: drm file-private structure to register the handle for
402 * @obj: object to register
403 * @handlep: pionter to return the created handle to the caller
404 *
405 * Create a handle for this object. This adds a handle reference
406 * to the object, which includes a regular reference count. Callers
407 * will likely want to dereference the object afterwards.
408 */
409int drm_gem_handle_create(struct drm_file *file_priv,
410 struct drm_gem_object *obj,
411 u32 *handlep)
412{
413 mutex_lock(&obj->dev->object_name_lock);
414
415 return drm_gem_handle_create_tail(file_priv, obj, handlep);
416}
417EXPORT_SYMBOL(drm_gem_handle_create);
418
419
420/**
421 * drm_gem_free_mmap_offset - release a fake mmap offset for an object
422 * @obj: obj in question
423 *
424 * This routine frees fake offsets allocated by drm_gem_create_mmap_offset().
425 */
426void
427drm_gem_free_mmap_offset(struct drm_gem_object *obj)
428{
429 struct drm_device *dev = obj->dev;
430
431 drm_vma_offset_remove(dev->vma_offset_manager, &obj->vma_node);
432}
433EXPORT_SYMBOL(drm_gem_free_mmap_offset);
434
435/**
436 * drm_gem_create_mmap_offset_size - create a fake mmap offset for an object
437 * @obj: obj in question
438 * @size: the virtual size
439 *
440 * GEM memory mapping works by handing back to userspace a fake mmap offset
441 * it can use in a subsequent mmap(2) call. The DRM core code then looks
442 * up the object based on the offset and sets up the various memory mapping
443 * structures.
444 *
445 * This routine allocates and attaches a fake offset for @obj, in cases where
446 * the virtual size differs from the physical size (ie. obj->size). Otherwise
447 * just use drm_gem_create_mmap_offset().
448 */
449int
450drm_gem_create_mmap_offset_size(struct drm_gem_object *obj, size_t size)
451{
452 struct drm_device *dev = obj->dev;
453
454 return drm_vma_offset_add(dev->vma_offset_manager, &obj->vma_node,
455 size / PAGE_SIZE);
456}
457EXPORT_SYMBOL(drm_gem_create_mmap_offset_size);
458
459/**
460 * drm_gem_create_mmap_offset - create a fake mmap offset for an object
461 * @obj: obj in question
462 *
463 * GEM memory mapping works by handing back to userspace a fake mmap offset
464 * it can use in a subsequent mmap(2) call. The DRM core code then looks
465 * up the object based on the offset and sets up the various memory mapping
466 * structures.
467 *
468 * This routine allocates and attaches a fake offset for @obj.
469 */
470int drm_gem_create_mmap_offset(struct drm_gem_object *obj)
471{
472 return drm_gem_create_mmap_offset_size(obj, obj->size);
473}
474EXPORT_SYMBOL(drm_gem_create_mmap_offset);
475
476/**
477 * drm_gem_get_pages - helper to allocate backing pages for a GEM object
478 * from shmem
479 * @obj: obj in question
480 *
481 * This reads the page-array of the shmem-backing storage of the given gem
482 * object. An array of pages is returned. If a page is not allocated or
483 * swapped-out, this will allocate/swap-in the required pages. Note that the
484 * whole object is covered by the page-array and pinned in memory.
485 *
486 * Use drm_gem_put_pages() to release the array and unpin all pages.
487 *
488 * This uses the GFP-mask set on the shmem-mapping (see mapping_set_gfp_mask()).
489 * If you require other GFP-masks, you have to do those allocations yourself.
490 *
491 * Note that you are not allowed to change gfp-zones during runtime. That is,
492 * shmem_read_mapping_page_gfp() must be called with the same gfp_zone(gfp) as
493 * set during initialization. If you have special zone constraints, set them
494 * after drm_gem_init_object() via mapping_set_gfp_mask(). shmem-core takes care
495 * to keep pages in the required zone during swap-in.
496 */
497struct page **drm_gem_get_pages(struct drm_gem_object *obj)
498{
499 struct address_space *mapping;
500 struct page *p, **pages;
501 int i, npages;
502
503 /* This is the shared memory object that backs the GEM resource */
504 mapping = file_inode(obj->filp)->i_mapping;
505
506 /* We already BUG_ON() for non-page-aligned sizes in
507 * drm_gem_object_init(), so we should never hit this unless
508 * driver author is doing something really wrong:
509 */
510 WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0);
511
512 npages = obj->size >> PAGE_SHIFT;
513
514 pages = drm_malloc_ab(npages, sizeof(struct page *));
515 if (pages == NULL)
516 return ERR_PTR(-ENOMEM);
517
518 for (i = 0; i < npages; i++) {
519 p = shmem_read_mapping_page(mapping, i);
520 if (IS_ERR(p))
521 goto fail;
522 pages[i] = p;
523
524 /* Make sure shmem keeps __GFP_DMA32 allocated pages in the
525 * correct region during swapin. Note that this requires
526 * __GFP_DMA32 to be set in mapping_gfp_mask(inode->i_mapping)
527 * so shmem can relocate pages during swapin if required.
528 */
529 BUG_ON(mapping_gfp_constraint(mapping, __GFP_DMA32) &&
530 (page_to_pfn(p) >= 0x00100000UL));
531 }
532
533 return pages;
534
535fail:
536 while (i--)
537 put_page(pages[i]);
538
539 drm_free_large(pages);
540 return ERR_CAST(p);
541}
542EXPORT_SYMBOL(drm_gem_get_pages);
543
544/**
545 * drm_gem_put_pages - helper to free backing pages for a GEM object
546 * @obj: obj in question
547 * @pages: pages to free
548 * @dirty: if true, pages will be marked as dirty
549 * @accessed: if true, the pages will be marked as accessed
550 */
551void drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages,
552 bool dirty, bool accessed)
553{
554 int i, npages;
555
556 /* We already BUG_ON() for non-page-aligned sizes in
557 * drm_gem_object_init(), so we should never hit this unless
558 * driver author is doing something really wrong:
559 */
560 WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0);
561
562 npages = obj->size >> PAGE_SHIFT;
563
564 for (i = 0; i < npages; i++) {
565 if (dirty)
566 set_page_dirty(pages[i]);
567
568 if (accessed)
569 mark_page_accessed(pages[i]);
570
571 /* Undo the reference we took when populating the table */
572 put_page(pages[i]);
573 }
574
575 drm_free_large(pages);
576}
577EXPORT_SYMBOL(drm_gem_put_pages);
578
579/**
580 * drm_gem_object_lookup - look up a GEM object from it's handle
581 * @dev: DRM device
582 * @filp: DRM file private date
583 * @handle: userspace handle
584 *
585 * Returns:
586 *
587 * A reference to the object named by the handle if such exists on @filp, NULL
588 * otherwise.
589 */
590struct drm_gem_object *
591drm_gem_object_lookup(struct drm_device *dev, struct drm_file *filp,
592 u32 handle)
593{
594 struct drm_gem_object *obj;
595
596 spin_lock(&filp->table_lock);
597
598 /* Check if we currently have a reference on the object */
599 obj = idr_find(&filp->object_idr, handle);
600 if (obj == NULL) {
601 spin_unlock(&filp->table_lock);
602 return NULL;
603 }
604
605 drm_gem_object_reference(obj);
606
607 spin_unlock(&filp->table_lock);
608
609 return obj;
610}
611EXPORT_SYMBOL(drm_gem_object_lookup);
612
613/**
614 * drm_gem_close_ioctl - implementation of the GEM_CLOSE ioctl
615 * @dev: drm_device
616 * @data: ioctl data
617 * @file_priv: drm file-private structure
618 *
619 * Releases the handle to an mm object.
620 */
621int
622drm_gem_close_ioctl(struct drm_device *dev, void *data,
623 struct drm_file *file_priv)
624{
625 struct drm_gem_close *args = data;
626 int ret;
627
628 if (!drm_core_check_feature(dev, DRIVER_GEM))
629 return -ENODEV;
630
631 ret = drm_gem_handle_delete(file_priv, args->handle);
632
633 return ret;
634}
635
636/**
637 * drm_gem_flink_ioctl - implementation of the GEM_FLINK ioctl
638 * @dev: drm_device
639 * @data: ioctl data
640 * @file_priv: drm file-private structure
641 *
642 * Create a global name for an object, returning the name.
643 *
644 * Note that the name does not hold a reference; when the object
645 * is freed, the name goes away.
646 */
647int
648drm_gem_flink_ioctl(struct drm_device *dev, void *data,
649 struct drm_file *file_priv)
650{
651 struct drm_gem_flink *args = data;
652 struct drm_gem_object *obj;
653 int ret;
654
655 if (!drm_core_check_feature(dev, DRIVER_GEM))
656 return -ENODEV;
657
658 obj = drm_gem_object_lookup(dev, file_priv, args->handle);
659 if (obj == NULL)
660 return -ENOENT;
661
662 mutex_lock(&dev->object_name_lock);
663 /* prevent races with concurrent gem_close. */
664 if (obj->handle_count == 0) {
665 ret = -ENOENT;
666 goto err;
667 }
668
669 if (!obj->name) {
670 ret = idr_alloc(&dev->object_name_idr, obj, 1, 0, GFP_KERNEL);
671 if (ret < 0)
672 goto err;
673
674 obj->name = ret;
675 }
676
677 args->name = (uint64_t) obj->name;
678 ret = 0;
679
680err:
681 mutex_unlock(&dev->object_name_lock);
682 drm_gem_object_unreference_unlocked(obj);
683 return ret;
684}
685
686/**
687 * drm_gem_open - implementation of the GEM_OPEN ioctl
688 * @dev: drm_device
689 * @data: ioctl data
690 * @file_priv: drm file-private structure
691 *
692 * Open an object using the global name, returning a handle and the size.
693 *
694 * This handle (of course) holds a reference to the object, so the object
695 * will not go away until the handle is deleted.
696 */
697int
698drm_gem_open_ioctl(struct drm_device *dev, void *data,
699 struct drm_file *file_priv)
700{
701 struct drm_gem_open *args = data;
702 struct drm_gem_object *obj;
703 int ret;
704 u32 handle;
705
706 if (!drm_core_check_feature(dev, DRIVER_GEM))
707 return -ENODEV;
708
709 mutex_lock(&dev->object_name_lock);
710 obj = idr_find(&dev->object_name_idr, (int) args->name);
711 if (obj) {
712 drm_gem_object_reference(obj);
713 } else {
714 mutex_unlock(&dev->object_name_lock);
715 return -ENOENT;
716 }
717
718 /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */
719 ret = drm_gem_handle_create_tail(file_priv, obj, &handle);
720 drm_gem_object_unreference_unlocked(obj);
721 if (ret)
722 return ret;
723
724 args->handle = handle;
725 args->size = obj->size;
726
727 return 0;
728}
729
730/**
731 * gem_gem_open - initalizes GEM file-private structures at devnode open time
732 * @dev: drm_device which is being opened by userspace
733 * @file_private: drm file-private structure to set up
734 *
735 * Called at device open time, sets up the structure for handling refcounting
736 * of mm objects.
737 */
738void
739drm_gem_open(struct drm_device *dev, struct drm_file *file_private)
740{
741 idr_init(&file_private->object_idr);
742 spin_lock_init(&file_private->table_lock);
743}
744
745/**
746 * drm_gem_release - release file-private GEM resources
747 * @dev: drm_device which is being closed by userspace
748 * @file_private: drm file-private structure to clean up
749 *
750 * Called at close time when the filp is going away.
751 *
752 * Releases any remaining references on objects by this filp.
753 */
754void
755drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
756{
757 idr_for_each(&file_private->object_idr,
758 &drm_gem_object_release_handle, file_private);
759 idr_destroy(&file_private->object_idr);
760}
761
762void
763drm_gem_object_release(struct drm_gem_object *obj)
764{
765 WARN_ON(obj->dma_buf);
766
767 if (obj->filp)
768 fput(obj->filp);
769
770 drm_gem_free_mmap_offset(obj);
771}
772EXPORT_SYMBOL(drm_gem_object_release);
773
774/**
775 * drm_gem_object_free - free a GEM object
776 * @kref: kref of the object to free
777 *
778 * Called after the last reference to the object has been lost.
779 * Must be called holding struct_ mutex
780 *
781 * Frees the object
782 */
783void
784drm_gem_object_free(struct kref *kref)
785{
786 struct drm_gem_object *obj =
787 container_of(kref, struct drm_gem_object, refcount);
788 struct drm_device *dev = obj->dev;
789
790 WARN_ON(!mutex_is_locked(&dev->struct_mutex));
791
792 if (dev->driver->gem_free_object != NULL)
793 dev->driver->gem_free_object(obj);
794}
795EXPORT_SYMBOL(drm_gem_object_free);
796
797/**
798 * drm_gem_vm_open - vma->ops->open implementation for GEM
799 * @vma: VM area structure
800 *
801 * This function implements the #vm_operations_struct open() callback for GEM
802 * drivers. This must be used together with drm_gem_vm_close().
803 */
804void drm_gem_vm_open(struct vm_area_struct *vma)
805{
806 struct drm_gem_object *obj = vma->vm_private_data;
807
808 drm_gem_object_reference(obj);
809}
810EXPORT_SYMBOL(drm_gem_vm_open);
811
812/**
813 * drm_gem_vm_close - vma->ops->close implementation for GEM
814 * @vma: VM area structure
815 *
816 * This function implements the #vm_operations_struct close() callback for GEM
817 * drivers. This must be used together with drm_gem_vm_open().
818 */
819void drm_gem_vm_close(struct vm_area_struct *vma)
820{
821 struct drm_gem_object *obj = vma->vm_private_data;
822
823 drm_gem_object_unreference_unlocked(obj);
824}
825EXPORT_SYMBOL(drm_gem_vm_close);
826
827/**
828 * drm_gem_mmap_obj - memory map a GEM object
829 * @obj: the GEM object to map
830 * @obj_size: the object size to be mapped, in bytes
831 * @vma: VMA for the area to be mapped
832 *
833 * Set up the VMA to prepare mapping of the GEM object using the gem_vm_ops
834 * provided by the driver. Depending on their requirements, drivers can either
835 * provide a fault handler in their gem_vm_ops (in which case any accesses to
836 * the object will be trapped, to perform migration, GTT binding, surface
837 * register allocation, or performance monitoring), or mmap the buffer memory
838 * synchronously after calling drm_gem_mmap_obj.
839 *
840 * This function is mainly intended to implement the DMABUF mmap operation, when
841 * the GEM object is not looked up based on its fake offset. To implement the
842 * DRM mmap operation, drivers should use the drm_gem_mmap() function.
843 *
844 * drm_gem_mmap_obj() assumes the user is granted access to the buffer while
845 * drm_gem_mmap() prevents unprivileged users from mapping random objects. So
846 * callers must verify access restrictions before calling this helper.
847 *
848 * Return 0 or success or -EINVAL if the object size is smaller than the VMA
849 * size, or if no gem_vm_ops are provided.
850 */
851int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
852 struct vm_area_struct *vma)
853{
854 struct drm_device *dev = obj->dev;
855
856 /* Check for valid size. */
857 if (obj_size < vma->vm_end - vma->vm_start)
858 return -EINVAL;
859
860 if (!dev->driver->gem_vm_ops)
861 return -EINVAL;
862
863 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
864 vma->vm_ops = dev->driver->gem_vm_ops;
865 vma->vm_private_data = obj;
866 vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
867
868 /* Take a ref for this mapping of the object, so that the fault
869 * handler can dereference the mmap offset's pointer to the object.
870 * This reference is cleaned up by the corresponding vm_close
871 * (which should happen whether the vma was created by this call, or
872 * by a vm_open due to mremap or partial unmap or whatever).
873 */
874 drm_gem_object_reference(obj);
875
876 return 0;
877}
878EXPORT_SYMBOL(drm_gem_mmap_obj);
879
880/**
881 * drm_gem_mmap - memory map routine for GEM objects
882 * @filp: DRM file pointer
883 * @vma: VMA for the area to be mapped
884 *
885 * If a driver supports GEM object mapping, mmap calls on the DRM file
886 * descriptor will end up here.
887 *
888 * Look up the GEM object based on the offset passed in (vma->vm_pgoff will
889 * contain the fake offset we created when the GTT map ioctl was called on
890 * the object) and map it with a call to drm_gem_mmap_obj().
891 *
892 * If the caller is not granted access to the buffer object, the mmap will fail
893 * with EACCES. Please see the vma manager for more information.
894 */
895int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
896{
897 struct drm_file *priv = filp->private_data;
898 struct drm_device *dev = priv->minor->dev;
899 struct drm_gem_object *obj = NULL;
900 struct drm_vma_offset_node *node;
901 int ret;
902
903 if (drm_device_is_unplugged(dev))
904 return -ENODEV;
905
906 drm_vma_offset_lock_lookup(dev->vma_offset_manager);
907 node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager,
908 vma->vm_pgoff,
909 vma_pages(vma));
910 if (likely(node)) {
911 obj = container_of(node, struct drm_gem_object, vma_node);
912 /*
913 * When the object is being freed, after it hits 0-refcnt it
914 * proceeds to tear down the object. In the process it will
915 * attempt to remove the VMA offset and so acquire this
916 * mgr->vm_lock. Therefore if we find an object with a 0-refcnt
917 * that matches our range, we know it is in the process of being
918 * destroyed and will be freed as soon as we release the lock -
919 * so we have to check for the 0-refcnted object and treat it as
920 * invalid.
921 */
922 if (!kref_get_unless_zero(&obj->refcount))
923 obj = NULL;
924 }
925 drm_vma_offset_unlock_lookup(dev->vma_offset_manager);
926
927 if (!obj)
928 return -EINVAL;
929
930 if (!drm_vma_node_is_allowed(node, filp)) {
931 drm_gem_object_unreference_unlocked(obj);
932 return -EACCES;
933 }
934
935 ret = drm_gem_mmap_obj(obj, drm_vma_node_size(node) << PAGE_SHIFT,
936 vma);
937
938 drm_gem_object_unreference_unlocked(obj);
939
940 return ret;
941}
942EXPORT_SYMBOL(drm_gem_mmap);
1/*
2 * Copyright © 2008 Intel Corporation
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 *
23 * Authors:
24 * Eric Anholt <eric@anholt.net>
25 *
26 */
27
28#include <linux/types.h>
29#include <linux/slab.h>
30#include <linux/mm.h>
31#include <linux/uaccess.h>
32#include <linux/fs.h>
33#include <linux/file.h>
34#include <linux/module.h>
35#include <linux/mman.h>
36#include <linux/pagemap.h>
37#include <linux/shmem_fs.h>
38#include <linux/dma-buf.h>
39#include <drm/drmP.h>
40#include <drm/drm_vma_manager.h>
41
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);