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1/*
2 * Copyright © 2012 Red Hat
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 * Dave Airlie <airlied@redhat.com>
25 * Rob Clark <rob.clark@linaro.org>
26 *
27 */
28
29#include <linux/export.h>
30#include <linux/dma-buf.h>
31#include <drm/drmP.h>
32
33/*
34 * DMA-BUF/GEM Object references and lifetime overview:
35 *
36 * On the export the dma_buf holds a reference to the exporting GEM
37 * object. It takes this reference in handle_to_fd_ioctl, when it
38 * first calls .prime_export and stores the exporting GEM object in
39 * the dma_buf priv. This reference is released when the dma_buf
40 * object goes away in the driver .release function.
41 *
42 * On the import the importing GEM object holds a reference to the
43 * dma_buf (which in turn holds a ref to the exporting GEM object).
44 * It takes that reference in the fd_to_handle ioctl.
45 * It calls dma_buf_get, creates an attachment to it and stores the
46 * attachment in the GEM object. When this attachment is destroyed
47 * when the imported object is destroyed, we remove the attachment
48 * and drop the reference to the dma_buf.
49 *
50 * Thus the chain of references always flows in one direction
51 * (avoiding loops): importing_gem -> dmabuf -> exporting_gem
52 *
53 * Self-importing: if userspace is using PRIME as a replacement for flink
54 * then it will get a fd->handle request for a GEM object that it created.
55 * Drivers should detect this situation and return back the gem object
56 * from the dma-buf private. Prime will do this automatically for drivers that
57 * use the drm_gem_prime_{import,export} helpers.
58 */
59
60struct drm_prime_member {
61 struct list_head entry;
62 struct dma_buf *dma_buf;
63 uint32_t handle;
64};
65
66struct drm_prime_attachment {
67 struct sg_table *sgt;
68 enum dma_data_direction dir;
69};
70
71static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv,
72 struct dma_buf *dma_buf, uint32_t handle)
73{
74 struct drm_prime_member *member;
75
76 member = kmalloc(sizeof(*member), GFP_KERNEL);
77 if (!member)
78 return -ENOMEM;
79
80 get_dma_buf(dma_buf);
81 member->dma_buf = dma_buf;
82 member->handle = handle;
83 list_add(&member->entry, &prime_fpriv->head);
84 return 0;
85}
86
87static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_private *prime_fpriv,
88 uint32_t handle)
89{
90 struct drm_prime_member *member;
91
92 list_for_each_entry(member, &prime_fpriv->head, entry) {
93 if (member->handle == handle)
94 return member->dma_buf;
95 }
96
97 return NULL;
98}
99
100static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv,
101 struct dma_buf *dma_buf,
102 uint32_t *handle)
103{
104 struct drm_prime_member *member;
105
106 list_for_each_entry(member, &prime_fpriv->head, entry) {
107 if (member->dma_buf == dma_buf) {
108 *handle = member->handle;
109 return 0;
110 }
111 }
112 return -ENOENT;
113}
114
115static int drm_gem_map_attach(struct dma_buf *dma_buf,
116 struct device *target_dev,
117 struct dma_buf_attachment *attach)
118{
119 struct drm_prime_attachment *prime_attach;
120 struct drm_gem_object *obj = dma_buf->priv;
121 struct drm_device *dev = obj->dev;
122
123 prime_attach = kzalloc(sizeof(*prime_attach), GFP_KERNEL);
124 if (!prime_attach)
125 return -ENOMEM;
126
127 prime_attach->dir = DMA_NONE;
128 attach->priv = prime_attach;
129
130 if (!dev->driver->gem_prime_pin)
131 return 0;
132
133 return dev->driver->gem_prime_pin(obj);
134}
135
136static void drm_gem_map_detach(struct dma_buf *dma_buf,
137 struct dma_buf_attachment *attach)
138{
139 struct drm_prime_attachment *prime_attach = attach->priv;
140 struct drm_gem_object *obj = dma_buf->priv;
141 struct drm_device *dev = obj->dev;
142 struct sg_table *sgt;
143
144 if (dev->driver->gem_prime_unpin)
145 dev->driver->gem_prime_unpin(obj);
146
147 if (!prime_attach)
148 return;
149
150 sgt = prime_attach->sgt;
151 if (sgt) {
152 if (prime_attach->dir != DMA_NONE)
153 dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents,
154 prime_attach->dir);
155 sg_free_table(sgt);
156 }
157
158 kfree(sgt);
159 kfree(prime_attach);
160 attach->priv = NULL;
161}
162
163void drm_prime_remove_buf_handle_locked(struct drm_prime_file_private *prime_fpriv,
164 struct dma_buf *dma_buf)
165{
166 struct drm_prime_member *member, *safe;
167
168 list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
169 if (member->dma_buf == dma_buf) {
170 dma_buf_put(dma_buf);
171 list_del(&member->entry);
172 kfree(member);
173 }
174 }
175}
176
177static struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
178 enum dma_data_direction dir)
179{
180 struct drm_prime_attachment *prime_attach = attach->priv;
181 struct drm_gem_object *obj = attach->dmabuf->priv;
182 struct sg_table *sgt;
183
184 if (WARN_ON(dir == DMA_NONE || !prime_attach))
185 return ERR_PTR(-EINVAL);
186
187 /* return the cached mapping when possible */
188 if (prime_attach->dir == dir)
189 return prime_attach->sgt;
190
191 /*
192 * two mappings with different directions for the same attachment are
193 * not allowed
194 */
195 if (WARN_ON(prime_attach->dir != DMA_NONE))
196 return ERR_PTR(-EBUSY);
197
198 sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
199
200 if (!IS_ERR(sgt)) {
201 if (!dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir)) {
202 sg_free_table(sgt);
203 kfree(sgt);
204 sgt = ERR_PTR(-ENOMEM);
205 } else {
206 prime_attach->sgt = sgt;
207 prime_attach->dir = dir;
208 }
209 }
210
211 return sgt;
212}
213
214static void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
215 struct sg_table *sgt,
216 enum dma_data_direction dir)
217{
218 /* nothing to be done here */
219}
220
221/**
222 * drm_gem_dmabuf_release - dma_buf release implementation for GEM
223 * @dma_buf: buffer to be released
224 *
225 * Generic release function for dma_bufs exported as PRIME buffers. GEM drivers
226 * must use this in their dma_buf ops structure as the release callback.
227 */
228void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
229{
230 struct drm_gem_object *obj = dma_buf->priv;
231
232 /* drop the reference on the export fd holds */
233 drm_gem_object_unreference_unlocked(obj);
234}
235EXPORT_SYMBOL(drm_gem_dmabuf_release);
236
237static void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
238{
239 struct drm_gem_object *obj = dma_buf->priv;
240 struct drm_device *dev = obj->dev;
241
242 return dev->driver->gem_prime_vmap(obj);
243}
244
245static void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
246{
247 struct drm_gem_object *obj = dma_buf->priv;
248 struct drm_device *dev = obj->dev;
249
250 dev->driver->gem_prime_vunmap(obj, vaddr);
251}
252
253static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
254 unsigned long page_num)
255{
256 return NULL;
257}
258
259static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
260 unsigned long page_num, void *addr)
261{
262
263}
264static void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf,
265 unsigned long page_num)
266{
267 return NULL;
268}
269
270static void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
271 unsigned long page_num, void *addr)
272{
273
274}
275
276static int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf,
277 struct vm_area_struct *vma)
278{
279 struct drm_gem_object *obj = dma_buf->priv;
280 struct drm_device *dev = obj->dev;
281
282 if (!dev->driver->gem_prime_mmap)
283 return -ENOSYS;
284
285 return dev->driver->gem_prime_mmap(obj, vma);
286}
287
288static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
289 .attach = drm_gem_map_attach,
290 .detach = drm_gem_map_detach,
291 .map_dma_buf = drm_gem_map_dma_buf,
292 .unmap_dma_buf = drm_gem_unmap_dma_buf,
293 .release = drm_gem_dmabuf_release,
294 .kmap = drm_gem_dmabuf_kmap,
295 .kmap_atomic = drm_gem_dmabuf_kmap_atomic,
296 .kunmap = drm_gem_dmabuf_kunmap,
297 .kunmap_atomic = drm_gem_dmabuf_kunmap_atomic,
298 .mmap = drm_gem_dmabuf_mmap,
299 .vmap = drm_gem_dmabuf_vmap,
300 .vunmap = drm_gem_dmabuf_vunmap,
301};
302
303/**
304 * DOC: PRIME Helpers
305 *
306 * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
307 * simpler APIs by using the helper functions @drm_gem_prime_export and
308 * @drm_gem_prime_import. These functions implement dma-buf support in terms of
309 * five lower-level driver callbacks:
310 *
311 * Export callbacks:
312 *
313 * - @gem_prime_pin (optional): prepare a GEM object for exporting
314 *
315 * - @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
316 *
317 * - @gem_prime_vmap: vmap a buffer exported by your driver
318 *
319 * - @gem_prime_vunmap: vunmap a buffer exported by your driver
320 *
321 * Import callback:
322 *
323 * - @gem_prime_import_sg_table (import): produce a GEM object from another
324 * driver's scatter/gather table
325 */
326
327/**
328 * drm_gem_prime_export - helper library implemention of the export callback
329 * @dev: drm_device to export from
330 * @obj: GEM object to export
331 * @flags: flags like DRM_CLOEXEC
332 *
333 * This is the implementation of the gem_prime_export functions for GEM drivers
334 * using the PRIME helpers.
335 */
336struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
337 struct drm_gem_object *obj, int flags)
338{
339 return dma_buf_export(obj, &drm_gem_prime_dmabuf_ops, obj->size, flags);
340}
341EXPORT_SYMBOL(drm_gem_prime_export);
342
343static struct dma_buf *export_and_register_object(struct drm_device *dev,
344 struct drm_gem_object *obj,
345 uint32_t flags)
346{
347 struct dma_buf *dmabuf;
348
349 /* prevent races with concurrent gem_close. */
350 if (obj->handle_count == 0) {
351 dmabuf = ERR_PTR(-ENOENT);
352 return dmabuf;
353 }
354
355 dmabuf = dev->driver->gem_prime_export(dev, obj, flags);
356 if (IS_ERR(dmabuf)) {
357 /* normally the created dma-buf takes ownership of the ref,
358 * but if that fails then drop the ref
359 */
360 return dmabuf;
361 }
362
363 /*
364 * Note that callers do not need to clean up the export cache
365 * since the check for obj->handle_count guarantees that someone
366 * will clean it up.
367 */
368 obj->dma_buf = dmabuf;
369 get_dma_buf(obj->dma_buf);
370 /* Grab a new ref since the callers is now used by the dma-buf */
371 drm_gem_object_reference(obj);
372
373 return dmabuf;
374}
375
376/**
377 * drm_gem_prime_handle_to_fd - PRIME export function for GEM drivers
378 * @dev: dev to export the buffer from
379 * @file_priv: drm file-private structure
380 * @handle: buffer handle to export
381 * @flags: flags like DRM_CLOEXEC
382 * @prime_fd: pointer to storage for the fd id of the create dma-buf
383 *
384 * This is the PRIME export function which must be used mandatorily by GEM
385 * drivers to ensure correct lifetime management of the underlying GEM object.
386 * The actual exporting from GEM object to a dma-buf is done through the
387 * gem_prime_export driver callback.
388 */
389int drm_gem_prime_handle_to_fd(struct drm_device *dev,
390 struct drm_file *file_priv, uint32_t handle,
391 uint32_t flags,
392 int *prime_fd)
393{
394 struct drm_gem_object *obj;
395 int ret = 0;
396 struct dma_buf *dmabuf;
397
398 mutex_lock(&file_priv->prime.lock);
399 obj = drm_gem_object_lookup(dev, file_priv, handle);
400 if (!obj) {
401 ret = -ENOENT;
402 goto out_unlock;
403 }
404
405 dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle);
406 if (dmabuf) {
407 get_dma_buf(dmabuf);
408 goto out_have_handle;
409 }
410
411 mutex_lock(&dev->object_name_lock);
412 /* re-export the original imported object */
413 if (obj->import_attach) {
414 dmabuf = obj->import_attach->dmabuf;
415 get_dma_buf(dmabuf);
416 goto out_have_obj;
417 }
418
419 if (obj->dma_buf) {
420 get_dma_buf(obj->dma_buf);
421 dmabuf = obj->dma_buf;
422 goto out_have_obj;
423 }
424
425 dmabuf = export_and_register_object(dev, obj, flags);
426 if (IS_ERR(dmabuf)) {
427 /* normally the created dma-buf takes ownership of the ref,
428 * but if that fails then drop the ref
429 */
430 ret = PTR_ERR(dmabuf);
431 mutex_unlock(&dev->object_name_lock);
432 goto out;
433 }
434
435out_have_obj:
436 /*
437 * If we've exported this buffer then cheat and add it to the import list
438 * so we get the correct handle back. We must do this under the
439 * protection of dev->object_name_lock to ensure that a racing gem close
440 * ioctl doesn't miss to remove this buffer handle from the cache.
441 */
442 ret = drm_prime_add_buf_handle(&file_priv->prime,
443 dmabuf, handle);
444 mutex_unlock(&dev->object_name_lock);
445 if (ret)
446 goto fail_put_dmabuf;
447
448out_have_handle:
449 ret = dma_buf_fd(dmabuf, flags);
450 /*
451 * We must _not_ remove the buffer from the handle cache since the newly
452 * created dma buf is already linked in the global obj->dma_buf pointer,
453 * and that is invariant as long as a userspace gem handle exists.
454 * Closing the handle will clean out the cache anyway, so we don't leak.
455 */
456 if (ret < 0) {
457 goto fail_put_dmabuf;
458 } else {
459 *prime_fd = ret;
460 ret = 0;
461 }
462
463 goto out;
464
465fail_put_dmabuf:
466 dma_buf_put(dmabuf);
467out:
468 drm_gem_object_unreference_unlocked(obj);
469out_unlock:
470 mutex_unlock(&file_priv->prime.lock);
471
472 return ret;
473}
474EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
475
476/**
477 * drm_gem_prime_import - helper library implemention of the import callback
478 * @dev: drm_device to import into
479 * @dma_buf: dma-buf object to import
480 *
481 * This is the implementation of the gem_prime_import functions for GEM drivers
482 * using the PRIME helpers.
483 */
484struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
485 struct dma_buf *dma_buf)
486{
487 struct dma_buf_attachment *attach;
488 struct sg_table *sgt;
489 struct drm_gem_object *obj;
490 int ret;
491
492 if (!dev->driver->gem_prime_import_sg_table)
493 return ERR_PTR(-EINVAL);
494
495 if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
496 obj = dma_buf->priv;
497 if (obj->dev == dev) {
498 /*
499 * Importing dmabuf exported from out own gem increases
500 * refcount on gem itself instead of f_count of dmabuf.
501 */
502 drm_gem_object_reference(obj);
503 return obj;
504 }
505 }
506
507 attach = dma_buf_attach(dma_buf, dev->dev);
508 if (IS_ERR(attach))
509 return ERR_CAST(attach);
510
511 get_dma_buf(dma_buf);
512
513 sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
514 if (IS_ERR(sgt)) {
515 ret = PTR_ERR(sgt);
516 goto fail_detach;
517 }
518
519 obj = dev->driver->gem_prime_import_sg_table(dev, dma_buf->size, sgt);
520 if (IS_ERR(obj)) {
521 ret = PTR_ERR(obj);
522 goto fail_unmap;
523 }
524
525 obj->import_attach = attach;
526
527 return obj;
528
529fail_unmap:
530 dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
531fail_detach:
532 dma_buf_detach(dma_buf, attach);
533 dma_buf_put(dma_buf);
534
535 return ERR_PTR(ret);
536}
537EXPORT_SYMBOL(drm_gem_prime_import);
538
539/**
540 * drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
541 * @dev: dev to export the buffer from
542 * @file_priv: drm file-private structure
543 * @prime_fd: fd id of the dma-buf which should be imported
544 * @handle: pointer to storage for the handle of the imported buffer object
545 *
546 * This is the PRIME import function which must be used mandatorily by GEM
547 * drivers to ensure correct lifetime management of the underlying GEM object.
548 * The actual importing of GEM object from the dma-buf is done through the
549 * gem_import_export driver callback.
550 */
551int drm_gem_prime_fd_to_handle(struct drm_device *dev,
552 struct drm_file *file_priv, int prime_fd,
553 uint32_t *handle)
554{
555 struct dma_buf *dma_buf;
556 struct drm_gem_object *obj;
557 int ret;
558
559 dma_buf = dma_buf_get(prime_fd);
560 if (IS_ERR(dma_buf))
561 return PTR_ERR(dma_buf);
562
563 mutex_lock(&file_priv->prime.lock);
564
565 ret = drm_prime_lookup_buf_handle(&file_priv->prime,
566 dma_buf, handle);
567 if (ret == 0)
568 goto out_put;
569
570 /* never seen this one, need to import */
571 mutex_lock(&dev->object_name_lock);
572 obj = dev->driver->gem_prime_import(dev, dma_buf);
573 if (IS_ERR(obj)) {
574 ret = PTR_ERR(obj);
575 goto out_unlock;
576 }
577
578 if (obj->dma_buf) {
579 WARN_ON(obj->dma_buf != dma_buf);
580 } else {
581 obj->dma_buf = dma_buf;
582 get_dma_buf(dma_buf);
583 }
584
585 /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */
586 ret = drm_gem_handle_create_tail(file_priv, obj, handle);
587 drm_gem_object_unreference_unlocked(obj);
588 if (ret)
589 goto out_put;
590
591 ret = drm_prime_add_buf_handle(&file_priv->prime,
592 dma_buf, *handle);
593 if (ret)
594 goto fail;
595
596 mutex_unlock(&file_priv->prime.lock);
597
598 dma_buf_put(dma_buf);
599
600 return 0;
601
602fail:
603 /* hmm, if driver attached, we are relying on the free-object path
604 * to detach.. which seems ok..
605 */
606 drm_gem_handle_delete(file_priv, *handle);
607out_unlock:
608 mutex_unlock(&dev->object_name_lock);
609out_put:
610 dma_buf_put(dma_buf);
611 mutex_unlock(&file_priv->prime.lock);
612 return ret;
613}
614EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
615
616int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
617 struct drm_file *file_priv)
618{
619 struct drm_prime_handle *args = data;
620 uint32_t flags;
621
622 if (!drm_core_check_feature(dev, DRIVER_PRIME))
623 return -EINVAL;
624
625 if (!dev->driver->prime_handle_to_fd)
626 return -ENOSYS;
627
628 /* check flags are valid */
629 if (args->flags & ~DRM_CLOEXEC)
630 return -EINVAL;
631
632 /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
633 flags = args->flags & DRM_CLOEXEC;
634
635 return dev->driver->prime_handle_to_fd(dev, file_priv,
636 args->handle, flags, &args->fd);
637}
638
639int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
640 struct drm_file *file_priv)
641{
642 struct drm_prime_handle *args = data;
643
644 if (!drm_core_check_feature(dev, DRIVER_PRIME))
645 return -EINVAL;
646
647 if (!dev->driver->prime_fd_to_handle)
648 return -ENOSYS;
649
650 return dev->driver->prime_fd_to_handle(dev, file_priv,
651 args->fd, &args->handle);
652}
653
654/**
655 * drm_prime_pages_to_sg - converts a page array into an sg list
656 * @pages: pointer to the array of page pointers to convert
657 * @nr_pages: length of the page vector
658 *
659 * This helper creates an sg table object from a set of pages
660 * the driver is responsible for mapping the pages into the
661 * importers address space for use with dma_buf itself.
662 */
663struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages)
664{
665 struct sg_table *sg = NULL;
666 int ret;
667
668 sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
669 if (!sg) {
670 ret = -ENOMEM;
671 goto out;
672 }
673
674 ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
675 nr_pages << PAGE_SHIFT, GFP_KERNEL);
676 if (ret)
677 goto out;
678
679 return sg;
680out:
681 kfree(sg);
682 return ERR_PTR(ret);
683}
684EXPORT_SYMBOL(drm_prime_pages_to_sg);
685
686/**
687 * drm_prime_sg_to_page_addr_arrays - convert an sg table into a page array
688 * @sgt: scatter-gather table to convert
689 * @pages: array of page pointers to store the page array in
690 * @addrs: optional array to store the dma bus address of each page
691 * @max_pages: size of both the passed-in arrays
692 *
693 * Exports an sg table into an array of pages and addresses. This is currently
694 * required by the TTM driver in order to do correct fault handling.
695 */
696int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
697 dma_addr_t *addrs, int max_pages)
698{
699 unsigned count;
700 struct scatterlist *sg;
701 struct page *page;
702 u32 len;
703 int pg_index;
704 dma_addr_t addr;
705
706 pg_index = 0;
707 for_each_sg(sgt->sgl, sg, sgt->nents, count) {
708 len = sg->length;
709 page = sg_page(sg);
710 addr = sg_dma_address(sg);
711
712 while (len > 0) {
713 if (WARN_ON(pg_index >= max_pages))
714 return -1;
715 pages[pg_index] = page;
716 if (addrs)
717 addrs[pg_index] = addr;
718
719 page++;
720 addr += PAGE_SIZE;
721 len -= PAGE_SIZE;
722 pg_index++;
723 }
724 }
725 return 0;
726}
727EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
728
729/**
730 * drm_prime_gem_destroy - helper to clean up a PRIME-imported GEM object
731 * @obj: GEM object which was created from a dma-buf
732 * @sg: the sg-table which was pinned at import time
733 *
734 * This is the cleanup functions which GEM drivers need to call when they use
735 * @drm_gem_prime_import to import dma-bufs.
736 */
737void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
738{
739 struct dma_buf_attachment *attach;
740 struct dma_buf *dma_buf;
741 attach = obj->import_attach;
742 if (sg)
743 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
744 dma_buf = attach->dmabuf;
745 dma_buf_detach(attach->dmabuf, attach);
746 /* remove the reference */
747 dma_buf_put(dma_buf);
748}
749EXPORT_SYMBOL(drm_prime_gem_destroy);
750
751void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
752{
753 INIT_LIST_HEAD(&prime_fpriv->head);
754 mutex_init(&prime_fpriv->lock);
755}
756
757void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
758{
759 /* by now drm_gem_release should've made sure the list is empty */
760 WARN_ON(!list_empty(&prime_fpriv->head));
761}
1/*
2 * Copyright © 2012 Red Hat
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 * Dave Airlie <airlied@redhat.com>
25 * Rob Clark <rob.clark@linaro.org>
26 *
27 */
28
29#include <linux/export.h>
30#include <linux/dma-buf.h>
31#include <linux/rbtree.h>
32#include <linux/module.h>
33
34#include <drm/drm.h>
35#include <drm/drm_drv.h>
36#include <drm/drm_file.h>
37#include <drm/drm_framebuffer.h>
38#include <drm/drm_gem.h>
39#include <drm/drm_prime.h>
40
41#include "drm_internal.h"
42
43MODULE_IMPORT_NS(DMA_BUF);
44
45/**
46 * DOC: overview and lifetime rules
47 *
48 * Similar to GEM global names, PRIME file descriptors are also used to share
49 * buffer objects across processes. They offer additional security: as file
50 * descriptors must be explicitly sent over UNIX domain sockets to be shared
51 * between applications, they can't be guessed like the globally unique GEM
52 * names.
53 *
54 * Drivers that support the PRIME API implement the
55 * &drm_driver.prime_handle_to_fd and &drm_driver.prime_fd_to_handle operations.
56 * GEM based drivers must use drm_gem_prime_handle_to_fd() and
57 * drm_gem_prime_fd_to_handle() to implement these. For GEM based drivers the
58 * actual driver interfaces is provided through the &drm_gem_object_funcs.export
59 * and &drm_driver.gem_prime_import hooks.
60 *
61 * &dma_buf_ops implementations for GEM drivers are all individually exported
62 * for drivers which need to overwrite or reimplement some of them.
63 *
64 * Reference Counting for GEM Drivers
65 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
66 *
67 * On the export the &dma_buf holds a reference to the exported buffer object,
68 * usually a &drm_gem_object. It takes this reference in the PRIME_HANDLE_TO_FD
69 * IOCTL, when it first calls &drm_gem_object_funcs.export
70 * and stores the exporting GEM object in the &dma_buf.priv field. This
71 * reference needs to be released when the final reference to the &dma_buf
72 * itself is dropped and its &dma_buf_ops.release function is called. For
73 * GEM-based drivers, the &dma_buf should be exported using
74 * drm_gem_dmabuf_export() and then released by drm_gem_dmabuf_release().
75 *
76 * Thus the chain of references always flows in one direction, avoiding loops:
77 * importing GEM object -> dma-buf -> exported GEM bo. A further complication
78 * are the lookup caches for import and export. These are required to guarantee
79 * that any given object will always have only one unique userspace handle. This
80 * is required to allow userspace to detect duplicated imports, since some GEM
81 * drivers do fail command submissions if a given buffer object is listed more
82 * than once. These import and export caches in &drm_prime_file_private only
83 * retain a weak reference, which is cleaned up when the corresponding object is
84 * released.
85 *
86 * Self-importing: If userspace is using PRIME as a replacement for flink then
87 * it will get a fd->handle request for a GEM object that it created. Drivers
88 * should detect this situation and return back the underlying object from the
89 * dma-buf private. For GEM based drivers this is handled in
90 * drm_gem_prime_import() already.
91 */
92
93struct drm_prime_member {
94 struct dma_buf *dma_buf;
95 uint32_t handle;
96
97 struct rb_node dmabuf_rb;
98 struct rb_node handle_rb;
99};
100
101static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv,
102 struct dma_buf *dma_buf, uint32_t handle)
103{
104 struct drm_prime_member *member;
105 struct rb_node **p, *rb;
106
107 member = kmalloc(sizeof(*member), GFP_KERNEL);
108 if (!member)
109 return -ENOMEM;
110
111 get_dma_buf(dma_buf);
112 member->dma_buf = dma_buf;
113 member->handle = handle;
114
115 rb = NULL;
116 p = &prime_fpriv->dmabufs.rb_node;
117 while (*p) {
118 struct drm_prime_member *pos;
119
120 rb = *p;
121 pos = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
122 if (dma_buf > pos->dma_buf)
123 p = &rb->rb_right;
124 else
125 p = &rb->rb_left;
126 }
127 rb_link_node(&member->dmabuf_rb, rb, p);
128 rb_insert_color(&member->dmabuf_rb, &prime_fpriv->dmabufs);
129
130 rb = NULL;
131 p = &prime_fpriv->handles.rb_node;
132 while (*p) {
133 struct drm_prime_member *pos;
134
135 rb = *p;
136 pos = rb_entry(rb, struct drm_prime_member, handle_rb);
137 if (handle > pos->handle)
138 p = &rb->rb_right;
139 else
140 p = &rb->rb_left;
141 }
142 rb_link_node(&member->handle_rb, rb, p);
143 rb_insert_color(&member->handle_rb, &prime_fpriv->handles);
144
145 return 0;
146}
147
148static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_private *prime_fpriv,
149 uint32_t handle)
150{
151 struct rb_node *rb;
152
153 rb = prime_fpriv->handles.rb_node;
154 while (rb) {
155 struct drm_prime_member *member;
156
157 member = rb_entry(rb, struct drm_prime_member, handle_rb);
158 if (member->handle == handle)
159 return member->dma_buf;
160 else if (member->handle < handle)
161 rb = rb->rb_right;
162 else
163 rb = rb->rb_left;
164 }
165
166 return NULL;
167}
168
169static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv,
170 struct dma_buf *dma_buf,
171 uint32_t *handle)
172{
173 struct rb_node *rb;
174
175 rb = prime_fpriv->dmabufs.rb_node;
176 while (rb) {
177 struct drm_prime_member *member;
178
179 member = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
180 if (member->dma_buf == dma_buf) {
181 *handle = member->handle;
182 return 0;
183 } else if (member->dma_buf < dma_buf) {
184 rb = rb->rb_right;
185 } else {
186 rb = rb->rb_left;
187 }
188 }
189
190 return -ENOENT;
191}
192
193void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv,
194 uint32_t handle)
195{
196 struct rb_node *rb;
197
198 mutex_lock(&prime_fpriv->lock);
199
200 rb = prime_fpriv->handles.rb_node;
201 while (rb) {
202 struct drm_prime_member *member;
203
204 member = rb_entry(rb, struct drm_prime_member, handle_rb);
205 if (member->handle == handle) {
206 rb_erase(&member->handle_rb, &prime_fpriv->handles);
207 rb_erase(&member->dmabuf_rb, &prime_fpriv->dmabufs);
208
209 dma_buf_put(member->dma_buf);
210 kfree(member);
211 break;
212 } else if (member->handle < handle) {
213 rb = rb->rb_right;
214 } else {
215 rb = rb->rb_left;
216 }
217 }
218
219 mutex_unlock(&prime_fpriv->lock);
220}
221
222void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
223{
224 mutex_init(&prime_fpriv->lock);
225 prime_fpriv->dmabufs = RB_ROOT;
226 prime_fpriv->handles = RB_ROOT;
227}
228
229void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
230{
231 /* by now drm_gem_release should've made sure the list is empty */
232 WARN_ON(!RB_EMPTY_ROOT(&prime_fpriv->dmabufs));
233}
234
235/**
236 * drm_gem_dmabuf_export - &dma_buf export implementation for GEM
237 * @dev: parent device for the exported dmabuf
238 * @exp_info: the export information used by dma_buf_export()
239 *
240 * This wraps dma_buf_export() for use by generic GEM drivers that are using
241 * drm_gem_dmabuf_release(). In addition to calling dma_buf_export(), we take
242 * a reference to the &drm_device and the exported &drm_gem_object (stored in
243 * &dma_buf_export_info.priv) which is released by drm_gem_dmabuf_release().
244 *
245 * Returns the new dmabuf.
246 */
247struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
248 struct dma_buf_export_info *exp_info)
249{
250 struct drm_gem_object *obj = exp_info->priv;
251 struct dma_buf *dma_buf;
252
253 dma_buf = dma_buf_export(exp_info);
254 if (IS_ERR(dma_buf))
255 return dma_buf;
256
257 drm_dev_get(dev);
258 drm_gem_object_get(obj);
259 dma_buf->file->f_mapping = obj->dev->anon_inode->i_mapping;
260
261 return dma_buf;
262}
263EXPORT_SYMBOL(drm_gem_dmabuf_export);
264
265/**
266 * drm_gem_dmabuf_release - &dma_buf release implementation for GEM
267 * @dma_buf: buffer to be released
268 *
269 * Generic release function for dma_bufs exported as PRIME buffers. GEM drivers
270 * must use this in their &dma_buf_ops structure as the release callback.
271 * drm_gem_dmabuf_release() should be used in conjunction with
272 * drm_gem_dmabuf_export().
273 */
274void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
275{
276 struct drm_gem_object *obj = dma_buf->priv;
277 struct drm_device *dev = obj->dev;
278
279 /* drop the reference on the export fd holds */
280 drm_gem_object_put(obj);
281
282 drm_dev_put(dev);
283}
284EXPORT_SYMBOL(drm_gem_dmabuf_release);
285
286/**
287 * drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
288 * @dev: dev to export the buffer from
289 * @file_priv: drm file-private structure
290 * @prime_fd: fd id of the dma-buf which should be imported
291 * @handle: pointer to storage for the handle of the imported buffer object
292 *
293 * This is the PRIME import function which must be used mandatorily by GEM
294 * drivers to ensure correct lifetime management of the underlying GEM object.
295 * The actual importing of GEM object from the dma-buf is done through the
296 * &drm_driver.gem_prime_import driver callback.
297 *
298 * Returns 0 on success or a negative error code on failure.
299 */
300int drm_gem_prime_fd_to_handle(struct drm_device *dev,
301 struct drm_file *file_priv, int prime_fd,
302 uint32_t *handle)
303{
304 struct dma_buf *dma_buf;
305 struct drm_gem_object *obj;
306 int ret;
307
308 dma_buf = dma_buf_get(prime_fd);
309 if (IS_ERR(dma_buf))
310 return PTR_ERR(dma_buf);
311
312 mutex_lock(&file_priv->prime.lock);
313
314 ret = drm_prime_lookup_buf_handle(&file_priv->prime,
315 dma_buf, handle);
316 if (ret == 0)
317 goto out_put;
318
319 /* never seen this one, need to import */
320 mutex_lock(&dev->object_name_lock);
321 if (dev->driver->gem_prime_import)
322 obj = dev->driver->gem_prime_import(dev, dma_buf);
323 else
324 obj = drm_gem_prime_import(dev, dma_buf);
325 if (IS_ERR(obj)) {
326 ret = PTR_ERR(obj);
327 goto out_unlock;
328 }
329
330 if (obj->dma_buf) {
331 WARN_ON(obj->dma_buf != dma_buf);
332 } else {
333 obj->dma_buf = dma_buf;
334 get_dma_buf(dma_buf);
335 }
336
337 /* _handle_create_tail unconditionally unlocks dev->object_name_lock. */
338 ret = drm_gem_handle_create_tail(file_priv, obj, handle);
339 drm_gem_object_put(obj);
340 if (ret)
341 goto out_put;
342
343 ret = drm_prime_add_buf_handle(&file_priv->prime,
344 dma_buf, *handle);
345 mutex_unlock(&file_priv->prime.lock);
346 if (ret)
347 goto fail;
348
349 dma_buf_put(dma_buf);
350
351 return 0;
352
353fail:
354 /* hmm, if driver attached, we are relying on the free-object path
355 * to detach.. which seems ok..
356 */
357 drm_gem_handle_delete(file_priv, *handle);
358 dma_buf_put(dma_buf);
359 return ret;
360
361out_unlock:
362 mutex_unlock(&dev->object_name_lock);
363out_put:
364 mutex_unlock(&file_priv->prime.lock);
365 dma_buf_put(dma_buf);
366 return ret;
367}
368EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
369
370int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
371 struct drm_file *file_priv)
372{
373 struct drm_prime_handle *args = data;
374
375 if (!dev->driver->prime_fd_to_handle)
376 return -ENOSYS;
377
378 return dev->driver->prime_fd_to_handle(dev, file_priv,
379 args->fd, &args->handle);
380}
381
382static struct dma_buf *export_and_register_object(struct drm_device *dev,
383 struct drm_gem_object *obj,
384 uint32_t flags)
385{
386 struct dma_buf *dmabuf;
387
388 /* prevent races with concurrent gem_close. */
389 if (obj->handle_count == 0) {
390 dmabuf = ERR_PTR(-ENOENT);
391 return dmabuf;
392 }
393
394 if (obj->funcs && obj->funcs->export)
395 dmabuf = obj->funcs->export(obj, flags);
396 else
397 dmabuf = drm_gem_prime_export(obj, flags);
398 if (IS_ERR(dmabuf)) {
399 /* normally the created dma-buf takes ownership of the ref,
400 * but if that fails then drop the ref
401 */
402 return dmabuf;
403 }
404
405 /*
406 * Note that callers do not need to clean up the export cache
407 * since the check for obj->handle_count guarantees that someone
408 * will clean it up.
409 */
410 obj->dma_buf = dmabuf;
411 get_dma_buf(obj->dma_buf);
412
413 return dmabuf;
414}
415
416/**
417 * drm_gem_prime_handle_to_fd - PRIME export function for GEM drivers
418 * @dev: dev to export the buffer from
419 * @file_priv: drm file-private structure
420 * @handle: buffer handle to export
421 * @flags: flags like DRM_CLOEXEC
422 * @prime_fd: pointer to storage for the fd id of the create dma-buf
423 *
424 * This is the PRIME export function which must be used mandatorily by GEM
425 * drivers to ensure correct lifetime management of the underlying GEM object.
426 * The actual exporting from GEM object to a dma-buf is done through the
427 * &drm_gem_object_funcs.export callback.
428 */
429int drm_gem_prime_handle_to_fd(struct drm_device *dev,
430 struct drm_file *file_priv, uint32_t handle,
431 uint32_t flags,
432 int *prime_fd)
433{
434 struct drm_gem_object *obj;
435 int ret = 0;
436 struct dma_buf *dmabuf;
437
438 mutex_lock(&file_priv->prime.lock);
439 obj = drm_gem_object_lookup(file_priv, handle);
440 if (!obj) {
441 ret = -ENOENT;
442 goto out_unlock;
443 }
444
445 dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle);
446 if (dmabuf) {
447 get_dma_buf(dmabuf);
448 goto out_have_handle;
449 }
450
451 mutex_lock(&dev->object_name_lock);
452 /* re-export the original imported object */
453 if (obj->import_attach) {
454 dmabuf = obj->import_attach->dmabuf;
455 get_dma_buf(dmabuf);
456 goto out_have_obj;
457 }
458
459 if (obj->dma_buf) {
460 get_dma_buf(obj->dma_buf);
461 dmabuf = obj->dma_buf;
462 goto out_have_obj;
463 }
464
465 dmabuf = export_and_register_object(dev, obj, flags);
466 if (IS_ERR(dmabuf)) {
467 /* normally the created dma-buf takes ownership of the ref,
468 * but if that fails then drop the ref
469 */
470 ret = PTR_ERR(dmabuf);
471 mutex_unlock(&dev->object_name_lock);
472 goto out;
473 }
474
475out_have_obj:
476 /*
477 * If we've exported this buffer then cheat and add it to the import list
478 * so we get the correct handle back. We must do this under the
479 * protection of dev->object_name_lock to ensure that a racing gem close
480 * ioctl doesn't miss to remove this buffer handle from the cache.
481 */
482 ret = drm_prime_add_buf_handle(&file_priv->prime,
483 dmabuf, handle);
484 mutex_unlock(&dev->object_name_lock);
485 if (ret)
486 goto fail_put_dmabuf;
487
488out_have_handle:
489 ret = dma_buf_fd(dmabuf, flags);
490 /*
491 * We must _not_ remove the buffer from the handle cache since the newly
492 * created dma buf is already linked in the global obj->dma_buf pointer,
493 * and that is invariant as long as a userspace gem handle exists.
494 * Closing the handle will clean out the cache anyway, so we don't leak.
495 */
496 if (ret < 0) {
497 goto fail_put_dmabuf;
498 } else {
499 *prime_fd = ret;
500 ret = 0;
501 }
502
503 goto out;
504
505fail_put_dmabuf:
506 dma_buf_put(dmabuf);
507out:
508 drm_gem_object_put(obj);
509out_unlock:
510 mutex_unlock(&file_priv->prime.lock);
511
512 return ret;
513}
514EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
515
516int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
517 struct drm_file *file_priv)
518{
519 struct drm_prime_handle *args = data;
520
521 if (!dev->driver->prime_handle_to_fd)
522 return -ENOSYS;
523
524 /* check flags are valid */
525 if (args->flags & ~(DRM_CLOEXEC | DRM_RDWR))
526 return -EINVAL;
527
528 return dev->driver->prime_handle_to_fd(dev, file_priv,
529 args->handle, args->flags, &args->fd);
530}
531
532/**
533 * DOC: PRIME Helpers
534 *
535 * Drivers can implement &drm_gem_object_funcs.export and
536 * &drm_driver.gem_prime_import in terms of simpler APIs by using the helper
537 * functions drm_gem_prime_export() and drm_gem_prime_import(). These functions
538 * implement dma-buf support in terms of some lower-level helpers, which are
539 * again exported for drivers to use individually:
540 *
541 * Exporting buffers
542 * ~~~~~~~~~~~~~~~~~
543 *
544 * Optional pinning of buffers is handled at dma-buf attach and detach time in
545 * drm_gem_map_attach() and drm_gem_map_detach(). Backing storage itself is
546 * handled by drm_gem_map_dma_buf() and drm_gem_unmap_dma_buf(), which relies on
547 * &drm_gem_object_funcs.get_sg_table.
548 *
549 * For kernel-internal access there's drm_gem_dmabuf_vmap() and
550 * drm_gem_dmabuf_vunmap(). Userspace mmap support is provided by
551 * drm_gem_dmabuf_mmap().
552 *
553 * Note that these export helpers can only be used if the underlying backing
554 * storage is fully coherent and either permanently pinned, or it is safe to pin
555 * it indefinitely.
556 *
557 * FIXME: The underlying helper functions are named rather inconsistently.
558 *
559 * Importing buffers
560 * ~~~~~~~~~~~~~~~~~
561 *
562 * Importing dma-bufs using drm_gem_prime_import() relies on
563 * &drm_driver.gem_prime_import_sg_table.
564 *
565 * Note that similarly to the export helpers this permanently pins the
566 * underlying backing storage. Which is ok for scanout, but is not the best
567 * option for sharing lots of buffers for rendering.
568 */
569
570/**
571 * drm_gem_map_attach - dma_buf attach implementation for GEM
572 * @dma_buf: buffer to attach device to
573 * @attach: buffer attachment data
574 *
575 * Calls &drm_gem_object_funcs.pin for device specific handling. This can be
576 * used as the &dma_buf_ops.attach callback. Must be used together with
577 * drm_gem_map_detach().
578 *
579 * Returns 0 on success, negative error code on failure.
580 */
581int drm_gem_map_attach(struct dma_buf *dma_buf,
582 struct dma_buf_attachment *attach)
583{
584 struct drm_gem_object *obj = dma_buf->priv;
585
586 return drm_gem_pin(obj);
587}
588EXPORT_SYMBOL(drm_gem_map_attach);
589
590/**
591 * drm_gem_map_detach - dma_buf detach implementation for GEM
592 * @dma_buf: buffer to detach from
593 * @attach: attachment to be detached
594 *
595 * Calls &drm_gem_object_funcs.pin for device specific handling. Cleans up
596 * &dma_buf_attachment from drm_gem_map_attach(). This can be used as the
597 * &dma_buf_ops.detach callback.
598 */
599void drm_gem_map_detach(struct dma_buf *dma_buf,
600 struct dma_buf_attachment *attach)
601{
602 struct drm_gem_object *obj = dma_buf->priv;
603
604 drm_gem_unpin(obj);
605}
606EXPORT_SYMBOL(drm_gem_map_detach);
607
608/**
609 * drm_gem_map_dma_buf - map_dma_buf implementation for GEM
610 * @attach: attachment whose scatterlist is to be returned
611 * @dir: direction of DMA transfer
612 *
613 * Calls &drm_gem_object_funcs.get_sg_table and then maps the scatterlist. This
614 * can be used as the &dma_buf_ops.map_dma_buf callback. Should be used together
615 * with drm_gem_unmap_dma_buf().
616 *
617 * Returns:sg_table containing the scatterlist to be returned; returns ERR_PTR
618 * on error. May return -EINTR if it is interrupted by a signal.
619 */
620struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
621 enum dma_data_direction dir)
622{
623 struct drm_gem_object *obj = attach->dmabuf->priv;
624 struct sg_table *sgt;
625 int ret;
626
627 if (WARN_ON(dir == DMA_NONE))
628 return ERR_PTR(-EINVAL);
629
630 if (WARN_ON(!obj->funcs->get_sg_table))
631 return ERR_PTR(-ENOSYS);
632
633 sgt = obj->funcs->get_sg_table(obj);
634 if (IS_ERR(sgt))
635 return sgt;
636
637 ret = dma_map_sgtable(attach->dev, sgt, dir,
638 DMA_ATTR_SKIP_CPU_SYNC);
639 if (ret) {
640 sg_free_table(sgt);
641 kfree(sgt);
642 sgt = ERR_PTR(ret);
643 }
644
645 return sgt;
646}
647EXPORT_SYMBOL(drm_gem_map_dma_buf);
648
649/**
650 * drm_gem_unmap_dma_buf - unmap_dma_buf implementation for GEM
651 * @attach: attachment to unmap buffer from
652 * @sgt: scatterlist info of the buffer to unmap
653 * @dir: direction of DMA transfer
654 *
655 * This can be used as the &dma_buf_ops.unmap_dma_buf callback.
656 */
657void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
658 struct sg_table *sgt,
659 enum dma_data_direction dir)
660{
661 if (!sgt)
662 return;
663
664 dma_unmap_sgtable(attach->dev, sgt, dir, DMA_ATTR_SKIP_CPU_SYNC);
665 sg_free_table(sgt);
666 kfree(sgt);
667}
668EXPORT_SYMBOL(drm_gem_unmap_dma_buf);
669
670/**
671 * drm_gem_dmabuf_vmap - dma_buf vmap implementation for GEM
672 * @dma_buf: buffer to be mapped
673 * @map: the virtual address of the buffer
674 *
675 * Sets up a kernel virtual mapping. This can be used as the &dma_buf_ops.vmap
676 * callback. Calls into &drm_gem_object_funcs.vmap for device specific handling.
677 * The kernel virtual address is returned in map.
678 *
679 * Returns 0 on success or a negative errno code otherwise.
680 */
681int drm_gem_dmabuf_vmap(struct dma_buf *dma_buf, struct iosys_map *map)
682{
683 struct drm_gem_object *obj = dma_buf->priv;
684
685 return drm_gem_vmap(obj, map);
686}
687EXPORT_SYMBOL(drm_gem_dmabuf_vmap);
688
689/**
690 * drm_gem_dmabuf_vunmap - dma_buf vunmap implementation for GEM
691 * @dma_buf: buffer to be unmapped
692 * @map: the virtual address of the buffer
693 *
694 * Releases a kernel virtual mapping. This can be used as the
695 * &dma_buf_ops.vunmap callback. Calls into &drm_gem_object_funcs.vunmap for device specific handling.
696 */
697void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, struct iosys_map *map)
698{
699 struct drm_gem_object *obj = dma_buf->priv;
700
701 drm_gem_vunmap(obj, map);
702}
703EXPORT_SYMBOL(drm_gem_dmabuf_vunmap);
704
705/**
706 * drm_gem_prime_mmap - PRIME mmap function for GEM drivers
707 * @obj: GEM object
708 * @vma: Virtual address range
709 *
710 * This function sets up a userspace mapping for PRIME exported buffers using
711 * the same codepath that is used for regular GEM buffer mapping on the DRM fd.
712 * The fake GEM offset is added to vma->vm_pgoff and &drm_driver->fops->mmap is
713 * called to set up the mapping.
714 *
715 * Drivers can use this as their &drm_driver.gem_prime_mmap callback.
716 */
717int drm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
718{
719 struct drm_file *priv;
720 struct file *fil;
721 int ret;
722
723 /* Add the fake offset */
724 vma->vm_pgoff += drm_vma_node_start(&obj->vma_node);
725
726 if (obj->funcs && obj->funcs->mmap) {
727 vma->vm_ops = obj->funcs->vm_ops;
728
729 drm_gem_object_get(obj);
730 ret = obj->funcs->mmap(obj, vma);
731 if (ret) {
732 drm_gem_object_put(obj);
733 return ret;
734 }
735 vma->vm_private_data = obj;
736 return 0;
737 }
738
739 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
740 fil = kzalloc(sizeof(*fil), GFP_KERNEL);
741 if (!priv || !fil) {
742 ret = -ENOMEM;
743 goto out;
744 }
745
746 /* Used by drm_gem_mmap() to lookup the GEM object */
747 priv->minor = obj->dev->primary;
748 fil->private_data = priv;
749
750 ret = drm_vma_node_allow(&obj->vma_node, priv);
751 if (ret)
752 goto out;
753
754 ret = obj->dev->driver->fops->mmap(fil, vma);
755
756 drm_vma_node_revoke(&obj->vma_node, priv);
757out:
758 kfree(priv);
759 kfree(fil);
760
761 return ret;
762}
763EXPORT_SYMBOL(drm_gem_prime_mmap);
764
765/**
766 * drm_gem_dmabuf_mmap - dma_buf mmap implementation for GEM
767 * @dma_buf: buffer to be mapped
768 * @vma: virtual address range
769 *
770 * Provides memory mapping for the buffer. This can be used as the
771 * &dma_buf_ops.mmap callback. It just forwards to &drm_driver.gem_prime_mmap,
772 * which should be set to drm_gem_prime_mmap().
773 *
774 * FIXME: There's really no point to this wrapper, drivers which need anything
775 * else but drm_gem_prime_mmap can roll their own &dma_buf_ops.mmap callback.
776 *
777 * Returns 0 on success or a negative error code on failure.
778 */
779int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
780{
781 struct drm_gem_object *obj = dma_buf->priv;
782 struct drm_device *dev = obj->dev;
783
784 dma_resv_assert_held(dma_buf->resv);
785
786 if (!dev->driver->gem_prime_mmap)
787 return -ENOSYS;
788
789 return dev->driver->gem_prime_mmap(obj, vma);
790}
791EXPORT_SYMBOL(drm_gem_dmabuf_mmap);
792
793static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
794 .cache_sgt_mapping = true,
795 .attach = drm_gem_map_attach,
796 .detach = drm_gem_map_detach,
797 .map_dma_buf = drm_gem_map_dma_buf,
798 .unmap_dma_buf = drm_gem_unmap_dma_buf,
799 .release = drm_gem_dmabuf_release,
800 .mmap = drm_gem_dmabuf_mmap,
801 .vmap = drm_gem_dmabuf_vmap,
802 .vunmap = drm_gem_dmabuf_vunmap,
803};
804
805/**
806 * drm_prime_pages_to_sg - converts a page array into an sg list
807 * @dev: DRM device
808 * @pages: pointer to the array of page pointers to convert
809 * @nr_pages: length of the page vector
810 *
811 * This helper creates an sg table object from a set of pages
812 * the driver is responsible for mapping the pages into the
813 * importers address space for use with dma_buf itself.
814 *
815 * This is useful for implementing &drm_gem_object_funcs.get_sg_table.
816 */
817struct sg_table *drm_prime_pages_to_sg(struct drm_device *dev,
818 struct page **pages, unsigned int nr_pages)
819{
820 struct sg_table *sg;
821 size_t max_segment = 0;
822 int err;
823
824 sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
825 if (!sg)
826 return ERR_PTR(-ENOMEM);
827
828 if (dev)
829 max_segment = dma_max_mapping_size(dev->dev);
830 if (max_segment == 0)
831 max_segment = UINT_MAX;
832 err = sg_alloc_table_from_pages_segment(sg, pages, nr_pages, 0,
833 nr_pages << PAGE_SHIFT,
834 max_segment, GFP_KERNEL);
835 if (err) {
836 kfree(sg);
837 sg = ERR_PTR(err);
838 }
839 return sg;
840}
841EXPORT_SYMBOL(drm_prime_pages_to_sg);
842
843/**
844 * drm_prime_get_contiguous_size - returns the contiguous size of the buffer
845 * @sgt: sg_table describing the buffer to check
846 *
847 * This helper calculates the contiguous size in the DMA address space
848 * of the buffer described by the provided sg_table.
849 *
850 * This is useful for implementing
851 * &drm_gem_object_funcs.gem_prime_import_sg_table.
852 */
853unsigned long drm_prime_get_contiguous_size(struct sg_table *sgt)
854{
855 dma_addr_t expected = sg_dma_address(sgt->sgl);
856 struct scatterlist *sg;
857 unsigned long size = 0;
858 int i;
859
860 for_each_sgtable_dma_sg(sgt, sg, i) {
861 unsigned int len = sg_dma_len(sg);
862
863 if (!len)
864 break;
865 if (sg_dma_address(sg) != expected)
866 break;
867 expected += len;
868 size += len;
869 }
870 return size;
871}
872EXPORT_SYMBOL(drm_prime_get_contiguous_size);
873
874/**
875 * drm_gem_prime_export - helper library implementation of the export callback
876 * @obj: GEM object to export
877 * @flags: flags like DRM_CLOEXEC and DRM_RDWR
878 *
879 * This is the implementation of the &drm_gem_object_funcs.export functions for GEM drivers
880 * using the PRIME helpers. It is used as the default in
881 * drm_gem_prime_handle_to_fd().
882 */
883struct dma_buf *drm_gem_prime_export(struct drm_gem_object *obj,
884 int flags)
885{
886 struct drm_device *dev = obj->dev;
887 struct dma_buf_export_info exp_info = {
888 .exp_name = KBUILD_MODNAME, /* white lie for debug */
889 .owner = dev->driver->fops->owner,
890 .ops = &drm_gem_prime_dmabuf_ops,
891 .size = obj->size,
892 .flags = flags,
893 .priv = obj,
894 .resv = obj->resv,
895 };
896
897 return drm_gem_dmabuf_export(dev, &exp_info);
898}
899EXPORT_SYMBOL(drm_gem_prime_export);
900
901/**
902 * drm_gem_prime_import_dev - core implementation of the import callback
903 * @dev: drm_device to import into
904 * @dma_buf: dma-buf object to import
905 * @attach_dev: struct device to dma_buf attach
906 *
907 * This is the core of drm_gem_prime_import(). It's designed to be called by
908 * drivers who want to use a different device structure than &drm_device.dev for
909 * attaching via dma_buf. This function calls
910 * &drm_driver.gem_prime_import_sg_table internally.
911 *
912 * Drivers must arrange to call drm_prime_gem_destroy() from their
913 * &drm_gem_object_funcs.free hook when using this function.
914 */
915struct drm_gem_object *drm_gem_prime_import_dev(struct drm_device *dev,
916 struct dma_buf *dma_buf,
917 struct device *attach_dev)
918{
919 struct dma_buf_attachment *attach;
920 struct sg_table *sgt;
921 struct drm_gem_object *obj;
922 int ret;
923
924 if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
925 obj = dma_buf->priv;
926 if (obj->dev == dev) {
927 /*
928 * Importing dmabuf exported from out own gem increases
929 * refcount on gem itself instead of f_count of dmabuf.
930 */
931 drm_gem_object_get(obj);
932 return obj;
933 }
934 }
935
936 if (!dev->driver->gem_prime_import_sg_table)
937 return ERR_PTR(-EINVAL);
938
939 attach = dma_buf_attach(dma_buf, attach_dev);
940 if (IS_ERR(attach))
941 return ERR_CAST(attach);
942
943 get_dma_buf(dma_buf);
944
945 sgt = dma_buf_map_attachment_unlocked(attach, DMA_BIDIRECTIONAL);
946 if (IS_ERR(sgt)) {
947 ret = PTR_ERR(sgt);
948 goto fail_detach;
949 }
950
951 obj = dev->driver->gem_prime_import_sg_table(dev, attach, sgt);
952 if (IS_ERR(obj)) {
953 ret = PTR_ERR(obj);
954 goto fail_unmap;
955 }
956
957 obj->import_attach = attach;
958 obj->resv = dma_buf->resv;
959
960 return obj;
961
962fail_unmap:
963 dma_buf_unmap_attachment_unlocked(attach, sgt, DMA_BIDIRECTIONAL);
964fail_detach:
965 dma_buf_detach(dma_buf, attach);
966 dma_buf_put(dma_buf);
967
968 return ERR_PTR(ret);
969}
970EXPORT_SYMBOL(drm_gem_prime_import_dev);
971
972/**
973 * drm_gem_prime_import - helper library implementation of the import callback
974 * @dev: drm_device to import into
975 * @dma_buf: dma-buf object to import
976 *
977 * This is the implementation of the gem_prime_import functions for GEM drivers
978 * using the PRIME helpers. Drivers can use this as their
979 * &drm_driver.gem_prime_import implementation. It is used as the default
980 * implementation in drm_gem_prime_fd_to_handle().
981 *
982 * Drivers must arrange to call drm_prime_gem_destroy() from their
983 * &drm_gem_object_funcs.free hook when using this function.
984 */
985struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
986 struct dma_buf *dma_buf)
987{
988 return drm_gem_prime_import_dev(dev, dma_buf, dev->dev);
989}
990EXPORT_SYMBOL(drm_gem_prime_import);
991
992/**
993 * drm_prime_sg_to_page_array - convert an sg table into a page array
994 * @sgt: scatter-gather table to convert
995 * @pages: array of page pointers to store the pages in
996 * @max_entries: size of the passed-in array
997 *
998 * Exports an sg table into an array of pages.
999 *
1000 * This function is deprecated and strongly discouraged to be used.
1001 * The page array is only useful for page faults and those can corrupt fields
1002 * in the struct page if they are not handled by the exporting driver.
1003 */
1004int __deprecated drm_prime_sg_to_page_array(struct sg_table *sgt,
1005 struct page **pages,
1006 int max_entries)
1007{
1008 struct sg_page_iter page_iter;
1009 struct page **p = pages;
1010
1011 for_each_sgtable_page(sgt, &page_iter, 0) {
1012 if (WARN_ON(p - pages >= max_entries))
1013 return -1;
1014 *p++ = sg_page_iter_page(&page_iter);
1015 }
1016 return 0;
1017}
1018EXPORT_SYMBOL(drm_prime_sg_to_page_array);
1019
1020/**
1021 * drm_prime_sg_to_dma_addr_array - convert an sg table into a dma addr array
1022 * @sgt: scatter-gather table to convert
1023 * @addrs: array to store the dma bus address of each page
1024 * @max_entries: size of both the passed-in arrays
1025 *
1026 * Exports an sg table into an array of addresses.
1027 *
1028 * Drivers should use this in their &drm_driver.gem_prime_import_sg_table
1029 * implementation.
1030 */
1031int drm_prime_sg_to_dma_addr_array(struct sg_table *sgt, dma_addr_t *addrs,
1032 int max_entries)
1033{
1034 struct sg_dma_page_iter dma_iter;
1035 dma_addr_t *a = addrs;
1036
1037 for_each_sgtable_dma_page(sgt, &dma_iter, 0) {
1038 if (WARN_ON(a - addrs >= max_entries))
1039 return -1;
1040 *a++ = sg_page_iter_dma_address(&dma_iter);
1041 }
1042 return 0;
1043}
1044EXPORT_SYMBOL(drm_prime_sg_to_dma_addr_array);
1045
1046/**
1047 * drm_prime_gem_destroy - helper to clean up a PRIME-imported GEM object
1048 * @obj: GEM object which was created from a dma-buf
1049 * @sg: the sg-table which was pinned at import time
1050 *
1051 * This is the cleanup functions which GEM drivers need to call when they use
1052 * drm_gem_prime_import() or drm_gem_prime_import_dev() to import dma-bufs.
1053 */
1054void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
1055{
1056 struct dma_buf_attachment *attach;
1057 struct dma_buf *dma_buf;
1058
1059 attach = obj->import_attach;
1060 if (sg)
1061 dma_buf_unmap_attachment_unlocked(attach, sg, DMA_BIDIRECTIONAL);
1062 dma_buf = attach->dmabuf;
1063 dma_buf_detach(attach->dmabuf, attach);
1064 /* remove the reference */
1065 dma_buf_put(dma_buf);
1066}
1067EXPORT_SYMBOL(drm_prime_gem_destroy);