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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#include <drm/drm_gem.h>
33
34#include "drm_internal.h"
35
36/*
37 * DMA-BUF/GEM Object references and lifetime overview:
38 *
39 * On the export the dma_buf holds a reference to the exporting GEM
40 * object. It takes this reference in handle_to_fd_ioctl, when it
41 * first calls .prime_export and stores the exporting GEM object in
42 * the dma_buf priv. This reference is released when the dma_buf
43 * object goes away in the driver .release function.
44 *
45 * On the import the importing GEM object holds a reference to the
46 * dma_buf (which in turn holds a ref to the exporting GEM object).
47 * It takes that reference in the fd_to_handle ioctl.
48 * It calls dma_buf_get, creates an attachment to it and stores the
49 * attachment in the GEM object. When this attachment is destroyed
50 * when the imported object is destroyed, we remove the attachment
51 * and drop the reference to the dma_buf.
52 *
53 * Thus the chain of references always flows in one direction
54 * (avoiding loops): importing_gem -> dmabuf -> exporting_gem
55 *
56 * Self-importing: if userspace is using PRIME as a replacement for flink
57 * then it will get a fd->handle request for a GEM object that it created.
58 * Drivers should detect this situation and return back the gem object
59 * from the dma-buf private. Prime will do this automatically for drivers that
60 * use the drm_gem_prime_{import,export} helpers.
61 */
62
63struct drm_prime_member {
64 struct list_head entry;
65 struct dma_buf *dma_buf;
66 uint32_t handle;
67};
68
69struct drm_prime_attachment {
70 struct sg_table *sgt;
71 enum dma_data_direction dir;
72};
73
74static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv,
75 struct dma_buf *dma_buf, uint32_t handle)
76{
77 struct drm_prime_member *member;
78
79 member = kmalloc(sizeof(*member), GFP_KERNEL);
80 if (!member)
81 return -ENOMEM;
82
83 get_dma_buf(dma_buf);
84 member->dma_buf = dma_buf;
85 member->handle = handle;
86 list_add(&member->entry, &prime_fpriv->head);
87 return 0;
88}
89
90static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_private *prime_fpriv,
91 uint32_t handle)
92{
93 struct drm_prime_member *member;
94
95 list_for_each_entry(member, &prime_fpriv->head, entry) {
96 if (member->handle == handle)
97 return member->dma_buf;
98 }
99
100 return NULL;
101}
102
103static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv,
104 struct dma_buf *dma_buf,
105 uint32_t *handle)
106{
107 struct drm_prime_member *member;
108
109 list_for_each_entry(member, &prime_fpriv->head, entry) {
110 if (member->dma_buf == dma_buf) {
111 *handle = member->handle;
112 return 0;
113 }
114 }
115 return -ENOENT;
116}
117
118static int drm_gem_map_attach(struct dma_buf *dma_buf,
119 struct device *target_dev,
120 struct dma_buf_attachment *attach)
121{
122 struct drm_prime_attachment *prime_attach;
123 struct drm_gem_object *obj = dma_buf->priv;
124 struct drm_device *dev = obj->dev;
125
126 prime_attach = kzalloc(sizeof(*prime_attach), GFP_KERNEL);
127 if (!prime_attach)
128 return -ENOMEM;
129
130 prime_attach->dir = DMA_NONE;
131 attach->priv = prime_attach;
132
133 if (!dev->driver->gem_prime_pin)
134 return 0;
135
136 return dev->driver->gem_prime_pin(obj);
137}
138
139static void drm_gem_map_detach(struct dma_buf *dma_buf,
140 struct dma_buf_attachment *attach)
141{
142 struct drm_prime_attachment *prime_attach = attach->priv;
143 struct drm_gem_object *obj = dma_buf->priv;
144 struct drm_device *dev = obj->dev;
145 struct sg_table *sgt;
146
147 if (dev->driver->gem_prime_unpin)
148 dev->driver->gem_prime_unpin(obj);
149
150 if (!prime_attach)
151 return;
152
153 sgt = prime_attach->sgt;
154 if (sgt) {
155 if (prime_attach->dir != DMA_NONE)
156 dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents,
157 prime_attach->dir);
158 sg_free_table(sgt);
159 }
160
161 kfree(sgt);
162 kfree(prime_attach);
163 attach->priv = NULL;
164}
165
166void drm_prime_remove_buf_handle_locked(struct drm_prime_file_private *prime_fpriv,
167 struct dma_buf *dma_buf)
168{
169 struct drm_prime_member *member, *safe;
170
171 list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
172 if (member->dma_buf == dma_buf) {
173 dma_buf_put(dma_buf);
174 list_del(&member->entry);
175 kfree(member);
176 }
177 }
178}
179
180static struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
181 enum dma_data_direction dir)
182{
183 struct drm_prime_attachment *prime_attach = attach->priv;
184 struct drm_gem_object *obj = attach->dmabuf->priv;
185 struct sg_table *sgt;
186
187 if (WARN_ON(dir == DMA_NONE || !prime_attach))
188 return ERR_PTR(-EINVAL);
189
190 /* return the cached mapping when possible */
191 if (prime_attach->dir == dir)
192 return prime_attach->sgt;
193
194 /*
195 * two mappings with different directions for the same attachment are
196 * not allowed
197 */
198 if (WARN_ON(prime_attach->dir != DMA_NONE))
199 return ERR_PTR(-EBUSY);
200
201 sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
202
203 if (!IS_ERR(sgt)) {
204 if (!dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir)) {
205 sg_free_table(sgt);
206 kfree(sgt);
207 sgt = ERR_PTR(-ENOMEM);
208 } else {
209 prime_attach->sgt = sgt;
210 prime_attach->dir = dir;
211 }
212 }
213
214 return sgt;
215}
216
217static void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
218 struct sg_table *sgt,
219 enum dma_data_direction dir)
220{
221 /* nothing to be done here */
222}
223
224/**
225 * drm_gem_dmabuf_release - dma_buf release implementation for GEM
226 * @dma_buf: buffer to be released
227 *
228 * Generic release function for dma_bufs exported as PRIME buffers. GEM drivers
229 * must use this in their dma_buf ops structure as the release callback.
230 */
231void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
232{
233 struct drm_gem_object *obj = dma_buf->priv;
234
235 /* drop the reference on the export fd holds */
236 drm_gem_object_unreference_unlocked(obj);
237}
238EXPORT_SYMBOL(drm_gem_dmabuf_release);
239
240static void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
241{
242 struct drm_gem_object *obj = dma_buf->priv;
243 struct drm_device *dev = obj->dev;
244
245 return dev->driver->gem_prime_vmap(obj);
246}
247
248static void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
249{
250 struct drm_gem_object *obj = dma_buf->priv;
251 struct drm_device *dev = obj->dev;
252
253 dev->driver->gem_prime_vunmap(obj, vaddr);
254}
255
256static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
257 unsigned long page_num)
258{
259 return NULL;
260}
261
262static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
263 unsigned long page_num, void *addr)
264{
265
266}
267static void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf,
268 unsigned long page_num)
269{
270 return NULL;
271}
272
273static void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
274 unsigned long page_num, void *addr)
275{
276
277}
278
279static int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf,
280 struct vm_area_struct *vma)
281{
282 struct drm_gem_object *obj = dma_buf->priv;
283 struct drm_device *dev = obj->dev;
284
285 if (!dev->driver->gem_prime_mmap)
286 return -ENOSYS;
287
288 return dev->driver->gem_prime_mmap(obj, vma);
289}
290
291static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
292 .attach = drm_gem_map_attach,
293 .detach = drm_gem_map_detach,
294 .map_dma_buf = drm_gem_map_dma_buf,
295 .unmap_dma_buf = drm_gem_unmap_dma_buf,
296 .release = drm_gem_dmabuf_release,
297 .kmap = drm_gem_dmabuf_kmap,
298 .kmap_atomic = drm_gem_dmabuf_kmap_atomic,
299 .kunmap = drm_gem_dmabuf_kunmap,
300 .kunmap_atomic = drm_gem_dmabuf_kunmap_atomic,
301 .mmap = drm_gem_dmabuf_mmap,
302 .vmap = drm_gem_dmabuf_vmap,
303 .vunmap = drm_gem_dmabuf_vunmap,
304};
305
306/**
307 * DOC: PRIME Helpers
308 *
309 * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
310 * simpler APIs by using the helper functions @drm_gem_prime_export and
311 * @drm_gem_prime_import. These functions implement dma-buf support in terms of
312 * six lower-level driver callbacks:
313 *
314 * Export callbacks:
315 *
316 * * @gem_prime_pin (optional): prepare a GEM object for exporting
317 * * @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
318 * * @gem_prime_vmap: vmap a buffer exported by your driver
319 * * @gem_prime_vunmap: vunmap a buffer exported by your driver
320 * * @gem_prime_mmap (optional): mmap a buffer exported by your driver
321 *
322 * Import callback:
323 *
324 * * @gem_prime_import_sg_table (import): produce a GEM object from another
325 * driver's scatter/gather table
326 */
327
328/**
329 * drm_gem_prime_export - helper library implementation of the export callback
330 * @dev: drm_device to export from
331 * @obj: GEM object to export
332 * @flags: flags like DRM_CLOEXEC and DRM_RDWR
333 *
334 * This is the implementation of the gem_prime_export functions for GEM drivers
335 * using the PRIME helpers.
336 */
337struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
338 struct drm_gem_object *obj, int flags)
339{
340 DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
341
342 exp_info.ops = &drm_gem_prime_dmabuf_ops;
343 exp_info.size = obj->size;
344 exp_info.flags = flags;
345 exp_info.priv = obj;
346
347 if (dev->driver->gem_prime_res_obj)
348 exp_info.resv = dev->driver->gem_prime_res_obj(obj);
349
350 return dma_buf_export(&exp_info);
351}
352EXPORT_SYMBOL(drm_gem_prime_export);
353
354static struct dma_buf *export_and_register_object(struct drm_device *dev,
355 struct drm_gem_object *obj,
356 uint32_t flags)
357{
358 struct dma_buf *dmabuf;
359
360 /* prevent races with concurrent gem_close. */
361 if (obj->handle_count == 0) {
362 dmabuf = ERR_PTR(-ENOENT);
363 return dmabuf;
364 }
365
366 dmabuf = dev->driver->gem_prime_export(dev, obj, flags);
367 if (IS_ERR(dmabuf)) {
368 /* normally the created dma-buf takes ownership of the ref,
369 * but if that fails then drop the ref
370 */
371 return dmabuf;
372 }
373
374 /*
375 * Note that callers do not need to clean up the export cache
376 * since the check for obj->handle_count guarantees that someone
377 * will clean it up.
378 */
379 obj->dma_buf = dmabuf;
380 get_dma_buf(obj->dma_buf);
381 /* Grab a new ref since the callers is now used by the dma-buf */
382 drm_gem_object_reference(obj);
383
384 return dmabuf;
385}
386
387/**
388 * drm_gem_prime_handle_to_fd - PRIME export function for GEM drivers
389 * @dev: dev to export the buffer from
390 * @file_priv: drm file-private structure
391 * @handle: buffer handle to export
392 * @flags: flags like DRM_CLOEXEC
393 * @prime_fd: pointer to storage for the fd id of the create dma-buf
394 *
395 * This is the PRIME export function which must be used mandatorily by GEM
396 * drivers to ensure correct lifetime management of the underlying GEM object.
397 * The actual exporting from GEM object to a dma-buf is done through the
398 * gem_prime_export driver callback.
399 */
400int drm_gem_prime_handle_to_fd(struct drm_device *dev,
401 struct drm_file *file_priv, uint32_t handle,
402 uint32_t flags,
403 int *prime_fd)
404{
405 struct drm_gem_object *obj;
406 int ret = 0;
407 struct dma_buf *dmabuf;
408
409 mutex_lock(&file_priv->prime.lock);
410 obj = drm_gem_object_lookup(dev, file_priv, handle);
411 if (!obj) {
412 ret = -ENOENT;
413 goto out_unlock;
414 }
415
416 dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle);
417 if (dmabuf) {
418 get_dma_buf(dmabuf);
419 goto out_have_handle;
420 }
421
422 mutex_lock(&dev->object_name_lock);
423 /* re-export the original imported object */
424 if (obj->import_attach) {
425 dmabuf = obj->import_attach->dmabuf;
426 get_dma_buf(dmabuf);
427 goto out_have_obj;
428 }
429
430 if (obj->dma_buf) {
431 get_dma_buf(obj->dma_buf);
432 dmabuf = obj->dma_buf;
433 goto out_have_obj;
434 }
435
436 dmabuf = export_and_register_object(dev, obj, flags);
437 if (IS_ERR(dmabuf)) {
438 /* normally the created dma-buf takes ownership of the ref,
439 * but if that fails then drop the ref
440 */
441 ret = PTR_ERR(dmabuf);
442 mutex_unlock(&dev->object_name_lock);
443 goto out;
444 }
445
446out_have_obj:
447 /*
448 * If we've exported this buffer then cheat and add it to the import list
449 * so we get the correct handle back. We must do this under the
450 * protection of dev->object_name_lock to ensure that a racing gem close
451 * ioctl doesn't miss to remove this buffer handle from the cache.
452 */
453 ret = drm_prime_add_buf_handle(&file_priv->prime,
454 dmabuf, handle);
455 mutex_unlock(&dev->object_name_lock);
456 if (ret)
457 goto fail_put_dmabuf;
458
459out_have_handle:
460 ret = dma_buf_fd(dmabuf, flags);
461 /*
462 * We must _not_ remove the buffer from the handle cache since the newly
463 * created dma buf is already linked in the global obj->dma_buf pointer,
464 * and that is invariant as long as a userspace gem handle exists.
465 * Closing the handle will clean out the cache anyway, so we don't leak.
466 */
467 if (ret < 0) {
468 goto fail_put_dmabuf;
469 } else {
470 *prime_fd = ret;
471 ret = 0;
472 }
473
474 goto out;
475
476fail_put_dmabuf:
477 dma_buf_put(dmabuf);
478out:
479 drm_gem_object_unreference_unlocked(obj);
480out_unlock:
481 mutex_unlock(&file_priv->prime.lock);
482
483 return ret;
484}
485EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
486
487/**
488 * drm_gem_prime_import - helper library implementation of the import callback
489 * @dev: drm_device to import into
490 * @dma_buf: dma-buf object to import
491 *
492 * This is the implementation of the gem_prime_import functions for GEM drivers
493 * using the PRIME helpers.
494 */
495struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
496 struct dma_buf *dma_buf)
497{
498 struct dma_buf_attachment *attach;
499 struct sg_table *sgt;
500 struct drm_gem_object *obj;
501 int ret;
502
503 if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
504 obj = dma_buf->priv;
505 if (obj->dev == dev) {
506 /*
507 * Importing dmabuf exported from out own gem increases
508 * refcount on gem itself instead of f_count of dmabuf.
509 */
510 drm_gem_object_reference(obj);
511 return obj;
512 }
513 }
514
515 if (!dev->driver->gem_prime_import_sg_table)
516 return ERR_PTR(-EINVAL);
517
518 attach = dma_buf_attach(dma_buf, dev->dev);
519 if (IS_ERR(attach))
520 return ERR_CAST(attach);
521
522 get_dma_buf(dma_buf);
523
524 sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
525 if (IS_ERR(sgt)) {
526 ret = PTR_ERR(sgt);
527 goto fail_detach;
528 }
529
530 obj = dev->driver->gem_prime_import_sg_table(dev, attach, sgt);
531 if (IS_ERR(obj)) {
532 ret = PTR_ERR(obj);
533 goto fail_unmap;
534 }
535
536 obj->import_attach = attach;
537
538 return obj;
539
540fail_unmap:
541 dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
542fail_detach:
543 dma_buf_detach(dma_buf, attach);
544 dma_buf_put(dma_buf);
545
546 return ERR_PTR(ret);
547}
548EXPORT_SYMBOL(drm_gem_prime_import);
549
550/**
551 * drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
552 * @dev: dev to export the buffer from
553 * @file_priv: drm file-private structure
554 * @prime_fd: fd id of the dma-buf which should be imported
555 * @handle: pointer to storage for the handle of the imported buffer object
556 *
557 * This is the PRIME import function which must be used mandatorily by GEM
558 * drivers to ensure correct lifetime management of the underlying GEM object.
559 * The actual importing of GEM object from the dma-buf is done through the
560 * gem_import_export driver callback.
561 */
562int drm_gem_prime_fd_to_handle(struct drm_device *dev,
563 struct drm_file *file_priv, int prime_fd,
564 uint32_t *handle)
565{
566 struct dma_buf *dma_buf;
567 struct drm_gem_object *obj;
568 int ret;
569
570 dma_buf = dma_buf_get(prime_fd);
571 if (IS_ERR(dma_buf))
572 return PTR_ERR(dma_buf);
573
574 mutex_lock(&file_priv->prime.lock);
575
576 ret = drm_prime_lookup_buf_handle(&file_priv->prime,
577 dma_buf, handle);
578 if (ret == 0)
579 goto out_put;
580
581 /* never seen this one, need to import */
582 mutex_lock(&dev->object_name_lock);
583 obj = dev->driver->gem_prime_import(dev, dma_buf);
584 if (IS_ERR(obj)) {
585 ret = PTR_ERR(obj);
586 goto out_unlock;
587 }
588
589 if (obj->dma_buf) {
590 WARN_ON(obj->dma_buf != dma_buf);
591 } else {
592 obj->dma_buf = dma_buf;
593 get_dma_buf(dma_buf);
594 }
595
596 /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */
597 ret = drm_gem_handle_create_tail(file_priv, obj, handle);
598 drm_gem_object_unreference_unlocked(obj);
599 if (ret)
600 goto out_put;
601
602 ret = drm_prime_add_buf_handle(&file_priv->prime,
603 dma_buf, *handle);
604 if (ret)
605 goto fail;
606
607 mutex_unlock(&file_priv->prime.lock);
608
609 dma_buf_put(dma_buf);
610
611 return 0;
612
613fail:
614 /* hmm, if driver attached, we are relying on the free-object path
615 * to detach.. which seems ok..
616 */
617 drm_gem_handle_delete(file_priv, *handle);
618out_unlock:
619 mutex_unlock(&dev->object_name_lock);
620out_put:
621 dma_buf_put(dma_buf);
622 mutex_unlock(&file_priv->prime.lock);
623 return ret;
624}
625EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
626
627int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
628 struct drm_file *file_priv)
629{
630 struct drm_prime_handle *args = data;
631
632 if (!drm_core_check_feature(dev, DRIVER_PRIME))
633 return -EINVAL;
634
635 if (!dev->driver->prime_handle_to_fd)
636 return -ENOSYS;
637
638 /* check flags are valid */
639 if (args->flags & ~(DRM_CLOEXEC | DRM_RDWR))
640 return -EINVAL;
641
642 return dev->driver->prime_handle_to_fd(dev, file_priv,
643 args->handle, args->flags, &args->fd);
644}
645
646int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
647 struct drm_file *file_priv)
648{
649 struct drm_prime_handle *args = data;
650
651 if (!drm_core_check_feature(dev, DRIVER_PRIME))
652 return -EINVAL;
653
654 if (!dev->driver->prime_fd_to_handle)
655 return -ENOSYS;
656
657 return dev->driver->prime_fd_to_handle(dev, file_priv,
658 args->fd, &args->handle);
659}
660
661/**
662 * drm_prime_pages_to_sg - converts a page array into an sg list
663 * @pages: pointer to the array of page pointers to convert
664 * @nr_pages: length of the page vector
665 *
666 * This helper creates an sg table object from a set of pages
667 * the driver is responsible for mapping the pages into the
668 * importers address space for use with dma_buf itself.
669 */
670struct sg_table *drm_prime_pages_to_sg(struct page **pages, unsigned int nr_pages)
671{
672 struct sg_table *sg = NULL;
673 int ret;
674
675 sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
676 if (!sg) {
677 ret = -ENOMEM;
678 goto out;
679 }
680
681 ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
682 nr_pages << PAGE_SHIFT, GFP_KERNEL);
683 if (ret)
684 goto out;
685
686 return sg;
687out:
688 kfree(sg);
689 return ERR_PTR(ret);
690}
691EXPORT_SYMBOL(drm_prime_pages_to_sg);
692
693/**
694 * drm_prime_sg_to_page_addr_arrays - convert an sg table into a page array
695 * @sgt: scatter-gather table to convert
696 * @pages: array of page pointers to store the page array in
697 * @addrs: optional array to store the dma bus address of each page
698 * @max_pages: size of both the passed-in arrays
699 *
700 * Exports an sg table into an array of pages and addresses. This is currently
701 * required by the TTM driver in order to do correct fault handling.
702 */
703int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
704 dma_addr_t *addrs, int max_pages)
705{
706 unsigned count;
707 struct scatterlist *sg;
708 struct page *page;
709 u32 len;
710 int pg_index;
711 dma_addr_t addr;
712
713 pg_index = 0;
714 for_each_sg(sgt->sgl, sg, sgt->nents, count) {
715 len = sg->length;
716 page = sg_page(sg);
717 addr = sg_dma_address(sg);
718
719 while (len > 0) {
720 if (WARN_ON(pg_index >= max_pages))
721 return -1;
722 pages[pg_index] = page;
723 if (addrs)
724 addrs[pg_index] = addr;
725
726 page++;
727 addr += PAGE_SIZE;
728 len -= PAGE_SIZE;
729 pg_index++;
730 }
731 }
732 return 0;
733}
734EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
735
736/**
737 * drm_prime_gem_destroy - helper to clean up a PRIME-imported GEM object
738 * @obj: GEM object which was created from a dma-buf
739 * @sg: the sg-table which was pinned at import time
740 *
741 * This is the cleanup functions which GEM drivers need to call when they use
742 * @drm_gem_prime_import to import dma-bufs.
743 */
744void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
745{
746 struct dma_buf_attachment *attach;
747 struct dma_buf *dma_buf;
748 attach = obj->import_attach;
749 if (sg)
750 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
751 dma_buf = attach->dmabuf;
752 dma_buf_detach(attach->dmabuf, attach);
753 /* remove the reference */
754 dma_buf_put(dma_buf);
755}
756EXPORT_SYMBOL(drm_prime_gem_destroy);
757
758void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
759{
760 INIT_LIST_HEAD(&prime_fpriv->head);
761 mutex_init(&prime_fpriv->lock);
762}
763
764void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
765{
766 /* by now drm_gem_release should've made sure the list is empty */
767 WARN_ON(!list_empty(&prime_fpriv->head));
768}
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 drm_gem_object_funcs.export
55 * and &drm_driver.gem_prime_import hooks. &dma_buf_ops implementations for
56 * drivers are all individually exported for drivers which need to overwrite
57 * or reimplement some of them.
58 *
59 * Reference Counting for GEM Drivers
60 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
61 *
62 * On the export the &dma_buf holds a reference to the exported buffer object,
63 * usually a &drm_gem_object. It takes this reference in the PRIME_HANDLE_TO_FD
64 * IOCTL, when it first calls &drm_gem_object_funcs.export
65 * and stores the exporting GEM object in the &dma_buf.priv field. This
66 * reference needs to be released when the final reference to the &dma_buf
67 * itself is dropped and its &dma_buf_ops.release function is called. For
68 * GEM-based drivers, the &dma_buf should be exported using
69 * drm_gem_dmabuf_export() and then released by drm_gem_dmabuf_release().
70 *
71 * Thus the chain of references always flows in one direction, avoiding loops:
72 * importing GEM object -> dma-buf -> exported GEM bo. A further complication
73 * are the lookup caches for import and export. These are required to guarantee
74 * that any given object will always have only one unique userspace handle. This
75 * is required to allow userspace to detect duplicated imports, since some GEM
76 * drivers do fail command submissions if a given buffer object is listed more
77 * than once. These import and export caches in &drm_prime_file_private only
78 * retain a weak reference, which is cleaned up when the corresponding object is
79 * released.
80 *
81 * Self-importing: If userspace is using PRIME as a replacement for flink then
82 * it will get a fd->handle request for a GEM object that it created. Drivers
83 * should detect this situation and return back the underlying object from the
84 * dma-buf private. For GEM based drivers this is handled in
85 * drm_gem_prime_import() already.
86 */
87
88struct drm_prime_member {
89 struct dma_buf *dma_buf;
90 uint32_t handle;
91
92 struct rb_node dmabuf_rb;
93 struct rb_node handle_rb;
94};
95
96static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv,
97 struct dma_buf *dma_buf, uint32_t handle)
98{
99 struct drm_prime_member *member;
100 struct rb_node **p, *rb;
101
102 member = kmalloc(sizeof(*member), GFP_KERNEL);
103 if (!member)
104 return -ENOMEM;
105
106 get_dma_buf(dma_buf);
107 member->dma_buf = dma_buf;
108 member->handle = handle;
109
110 rb = NULL;
111 p = &prime_fpriv->dmabufs.rb_node;
112 while (*p) {
113 struct drm_prime_member *pos;
114
115 rb = *p;
116 pos = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
117 if (dma_buf > pos->dma_buf)
118 p = &rb->rb_right;
119 else
120 p = &rb->rb_left;
121 }
122 rb_link_node(&member->dmabuf_rb, rb, p);
123 rb_insert_color(&member->dmabuf_rb, &prime_fpriv->dmabufs);
124
125 rb = NULL;
126 p = &prime_fpriv->handles.rb_node;
127 while (*p) {
128 struct drm_prime_member *pos;
129
130 rb = *p;
131 pos = rb_entry(rb, struct drm_prime_member, handle_rb);
132 if (handle > pos->handle)
133 p = &rb->rb_right;
134 else
135 p = &rb->rb_left;
136 }
137 rb_link_node(&member->handle_rb, rb, p);
138 rb_insert_color(&member->handle_rb, &prime_fpriv->handles);
139
140 return 0;
141}
142
143static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_private *prime_fpriv,
144 uint32_t handle)
145{
146 struct rb_node *rb;
147
148 rb = prime_fpriv->handles.rb_node;
149 while (rb) {
150 struct drm_prime_member *member;
151
152 member = rb_entry(rb, struct drm_prime_member, handle_rb);
153 if (member->handle == handle)
154 return member->dma_buf;
155 else if (member->handle < handle)
156 rb = rb->rb_right;
157 else
158 rb = rb->rb_left;
159 }
160
161 return NULL;
162}
163
164static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv,
165 struct dma_buf *dma_buf,
166 uint32_t *handle)
167{
168 struct rb_node *rb;
169
170 rb = prime_fpriv->dmabufs.rb_node;
171 while (rb) {
172 struct drm_prime_member *member;
173
174 member = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
175 if (member->dma_buf == dma_buf) {
176 *handle = member->handle;
177 return 0;
178 } else if (member->dma_buf < dma_buf) {
179 rb = rb->rb_right;
180 } else {
181 rb = rb->rb_left;
182 }
183 }
184
185 return -ENOENT;
186}
187
188void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv,
189 uint32_t handle)
190{
191 struct rb_node *rb;
192
193 mutex_lock(&prime_fpriv->lock);
194
195 rb = prime_fpriv->handles.rb_node;
196 while (rb) {
197 struct drm_prime_member *member;
198
199 member = rb_entry(rb, struct drm_prime_member, handle_rb);
200 if (member->handle == handle) {
201 rb_erase(&member->handle_rb, &prime_fpriv->handles);
202 rb_erase(&member->dmabuf_rb, &prime_fpriv->dmabufs);
203
204 dma_buf_put(member->dma_buf);
205 kfree(member);
206 break;
207 } else if (member->handle < handle) {
208 rb = rb->rb_right;
209 } else {
210 rb = rb->rb_left;
211 }
212 }
213
214 mutex_unlock(&prime_fpriv->lock);
215}
216
217void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
218{
219 mutex_init(&prime_fpriv->lock);
220 prime_fpriv->dmabufs = RB_ROOT;
221 prime_fpriv->handles = RB_ROOT;
222}
223
224void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
225{
226 /* by now drm_gem_release should've made sure the list is empty */
227 WARN_ON(!RB_EMPTY_ROOT(&prime_fpriv->dmabufs));
228}
229
230/**
231 * drm_gem_dmabuf_export - &dma_buf export implementation for GEM
232 * @dev: parent device for the exported dmabuf
233 * @exp_info: the export information used by dma_buf_export()
234 *
235 * This wraps dma_buf_export() for use by generic GEM drivers that are using
236 * drm_gem_dmabuf_release(). In addition to calling dma_buf_export(), we take
237 * a reference to the &drm_device and the exported &drm_gem_object (stored in
238 * &dma_buf_export_info.priv) which is released by drm_gem_dmabuf_release().
239 *
240 * Returns the new dmabuf.
241 */
242struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
243 struct dma_buf_export_info *exp_info)
244{
245 struct drm_gem_object *obj = exp_info->priv;
246 struct dma_buf *dma_buf;
247
248 dma_buf = dma_buf_export(exp_info);
249 if (IS_ERR(dma_buf))
250 return dma_buf;
251
252 drm_dev_get(dev);
253 drm_gem_object_get(obj);
254 dma_buf->file->f_mapping = obj->dev->anon_inode->i_mapping;
255
256 return dma_buf;
257}
258EXPORT_SYMBOL(drm_gem_dmabuf_export);
259
260/**
261 * drm_gem_dmabuf_release - &dma_buf release implementation for GEM
262 * @dma_buf: buffer to be released
263 *
264 * Generic release function for dma_bufs exported as PRIME buffers. GEM drivers
265 * must use this in their &dma_buf_ops structure as the release callback.
266 * drm_gem_dmabuf_release() should be used in conjunction with
267 * drm_gem_dmabuf_export().
268 */
269void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
270{
271 struct drm_gem_object *obj = dma_buf->priv;
272 struct drm_device *dev = obj->dev;
273
274 /* drop the reference on the export fd holds */
275 drm_gem_object_put(obj);
276
277 drm_dev_put(dev);
278}
279EXPORT_SYMBOL(drm_gem_dmabuf_release);
280
281/**
282 * drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
283 * @dev: drm_device to import into
284 * @file_priv: drm file-private structure
285 * @prime_fd: fd id of the dma-buf which should be imported
286 * @handle: pointer to storage for the handle of the imported buffer object
287 *
288 * This is the PRIME import function which must be used mandatorily by GEM
289 * drivers to ensure correct lifetime management of the underlying GEM object.
290 * The actual importing of GEM object from the dma-buf is done through the
291 * &drm_driver.gem_prime_import driver callback.
292 *
293 * Returns 0 on success or a negative error code on failure.
294 */
295int drm_gem_prime_fd_to_handle(struct drm_device *dev,
296 struct drm_file *file_priv, int prime_fd,
297 uint32_t *handle)
298{
299 struct dma_buf *dma_buf;
300 struct drm_gem_object *obj;
301 int ret;
302
303 dma_buf = dma_buf_get(prime_fd);
304 if (IS_ERR(dma_buf))
305 return PTR_ERR(dma_buf);
306
307 mutex_lock(&file_priv->prime.lock);
308
309 ret = drm_prime_lookup_buf_handle(&file_priv->prime,
310 dma_buf, handle);
311 if (ret == 0)
312 goto out_put;
313
314 /* never seen this one, need to import */
315 mutex_lock(&dev->object_name_lock);
316 if (dev->driver->gem_prime_import)
317 obj = dev->driver->gem_prime_import(dev, dma_buf);
318 else
319 obj = drm_gem_prime_import(dev, dma_buf);
320 if (IS_ERR(obj)) {
321 ret = PTR_ERR(obj);
322 goto out_unlock;
323 }
324
325 if (obj->dma_buf) {
326 WARN_ON(obj->dma_buf != dma_buf);
327 } else {
328 obj->dma_buf = dma_buf;
329 get_dma_buf(dma_buf);
330 }
331
332 /* _handle_create_tail unconditionally unlocks dev->object_name_lock. */
333 ret = drm_gem_handle_create_tail(file_priv, obj, handle);
334 drm_gem_object_put(obj);
335 if (ret)
336 goto out_put;
337
338 ret = drm_prime_add_buf_handle(&file_priv->prime,
339 dma_buf, *handle);
340 mutex_unlock(&file_priv->prime.lock);
341 if (ret)
342 goto fail;
343
344 dma_buf_put(dma_buf);
345
346 return 0;
347
348fail:
349 /* hmm, if driver attached, we are relying on the free-object path
350 * to detach.. which seems ok..
351 */
352 drm_gem_handle_delete(file_priv, *handle);
353 dma_buf_put(dma_buf);
354 return ret;
355
356out_unlock:
357 mutex_unlock(&dev->object_name_lock);
358out_put:
359 mutex_unlock(&file_priv->prime.lock);
360 dma_buf_put(dma_buf);
361 return ret;
362}
363EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
364
365int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
366 struct drm_file *file_priv)
367{
368 struct drm_prime_handle *args = data;
369
370 if (dev->driver->prime_fd_to_handle) {
371 return dev->driver->prime_fd_to_handle(dev, file_priv, args->fd,
372 &args->handle);
373 }
374
375 return drm_gem_prime_fd_to_handle(dev, file_priv, args->fd, &args->handle);
376}
377
378static struct dma_buf *export_and_register_object(struct drm_device *dev,
379 struct drm_gem_object *obj,
380 uint32_t flags)
381{
382 struct dma_buf *dmabuf;
383
384 /* prevent races with concurrent gem_close. */
385 if (obj->handle_count == 0) {
386 dmabuf = ERR_PTR(-ENOENT);
387 return dmabuf;
388 }
389
390 if (obj->funcs && obj->funcs->export)
391 dmabuf = obj->funcs->export(obj, flags);
392 else
393 dmabuf = drm_gem_prime_export(obj, flags);
394 if (IS_ERR(dmabuf)) {
395 /* normally the created dma-buf takes ownership of the ref,
396 * but if that fails then drop the ref
397 */
398 return dmabuf;
399 }
400
401 /*
402 * Note that callers do not need to clean up the export cache
403 * since the check for obj->handle_count guarantees that someone
404 * will clean it up.
405 */
406 obj->dma_buf = dmabuf;
407 get_dma_buf(obj->dma_buf);
408
409 return dmabuf;
410}
411
412/**
413 * drm_gem_prime_handle_to_dmabuf - PRIME export function for GEM drivers
414 * @dev: dev to export the buffer from
415 * @file_priv: drm file-private structure
416 * @handle: buffer handle to export
417 * @flags: flags like DRM_CLOEXEC
418 *
419 * This is the PRIME export function which must be used mandatorily by GEM
420 * drivers to ensure correct lifetime management of the underlying GEM object.
421 * The actual exporting from GEM object to a dma-buf is done through the
422 * &drm_gem_object_funcs.export callback.
423 *
424 * Unlike drm_gem_prime_handle_to_fd(), it returns the struct dma_buf it
425 * has created, without attaching it to any file descriptors. The difference
426 * between those two is similar to that between anon_inode_getfile() and
427 * anon_inode_getfd(); insertion into descriptor table is something you
428 * can not revert if any cleanup is needed, so the descriptor-returning
429 * variants should only be used when you are past the last failure exit
430 * and the only thing left is passing the new file descriptor to userland.
431 * When all you need is the object itself or when you need to do something
432 * else that might fail, use that one instead.
433 */
434struct dma_buf *drm_gem_prime_handle_to_dmabuf(struct drm_device *dev,
435 struct drm_file *file_priv, uint32_t handle,
436 uint32_t flags)
437{
438 struct drm_gem_object *obj;
439 int ret = 0;
440 struct dma_buf *dmabuf;
441
442 mutex_lock(&file_priv->prime.lock);
443 obj = drm_gem_object_lookup(file_priv, handle);
444 if (!obj) {
445 dmabuf = ERR_PTR(-ENOENT);
446 goto out_unlock;
447 }
448
449 dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle);
450 if (dmabuf) {
451 get_dma_buf(dmabuf);
452 goto out;
453 }
454
455 mutex_lock(&dev->object_name_lock);
456 /* re-export the original imported object */
457 if (obj->import_attach) {
458 dmabuf = obj->import_attach->dmabuf;
459 get_dma_buf(dmabuf);
460 goto out_have_obj;
461 }
462
463 if (obj->dma_buf) {
464 get_dma_buf(obj->dma_buf);
465 dmabuf = obj->dma_buf;
466 goto out_have_obj;
467 }
468
469 dmabuf = export_and_register_object(dev, obj, flags);
470 if (IS_ERR(dmabuf)) {
471 /* normally the created dma-buf takes ownership of the ref,
472 * but if that fails then drop the ref
473 */
474 mutex_unlock(&dev->object_name_lock);
475 goto out;
476 }
477
478out_have_obj:
479 /*
480 * If we've exported this buffer then cheat and add it to the import list
481 * so we get the correct handle back. We must do this under the
482 * protection of dev->object_name_lock to ensure that a racing gem close
483 * ioctl doesn't miss to remove this buffer handle from the cache.
484 */
485 ret = drm_prime_add_buf_handle(&file_priv->prime,
486 dmabuf, handle);
487 mutex_unlock(&dev->object_name_lock);
488 if (ret) {
489 dma_buf_put(dmabuf);
490 dmabuf = ERR_PTR(ret);
491 }
492out:
493 drm_gem_object_put(obj);
494out_unlock:
495 mutex_unlock(&file_priv->prime.lock);
496 return dmabuf;
497}
498EXPORT_SYMBOL(drm_gem_prime_handle_to_dmabuf);
499
500/**
501 * drm_gem_prime_handle_to_fd - PRIME export function for GEM drivers
502 * @dev: dev to export the buffer from
503 * @file_priv: drm file-private structure
504 * @handle: buffer handle to export
505 * @flags: flags like DRM_CLOEXEC
506 * @prime_fd: pointer to storage for the fd id of the create dma-buf
507 *
508 * This is the PRIME export function which must be used mandatorily by GEM
509 * drivers to ensure correct lifetime management of the underlying GEM object.
510 * The actual exporting from GEM object to a dma-buf is done through the
511 * &drm_gem_object_funcs.export callback.
512 */
513int drm_gem_prime_handle_to_fd(struct drm_device *dev,
514 struct drm_file *file_priv, uint32_t handle,
515 uint32_t flags,
516 int *prime_fd)
517{
518 struct dma_buf *dmabuf;
519 int fd = get_unused_fd_flags(flags);
520
521 if (fd < 0)
522 return fd;
523
524 dmabuf = drm_gem_prime_handle_to_dmabuf(dev, file_priv, handle, flags);
525 if (IS_ERR(dmabuf)) {
526 put_unused_fd(fd);
527 return PTR_ERR(dmabuf);
528 }
529
530 fd_install(fd, dmabuf->file);
531 *prime_fd = fd;
532 return 0;
533}
534EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
535
536int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
537 struct drm_file *file_priv)
538{
539 struct drm_prime_handle *args = data;
540
541 /* check flags are valid */
542 if (args->flags & ~(DRM_CLOEXEC | DRM_RDWR))
543 return -EINVAL;
544
545 if (dev->driver->prime_handle_to_fd) {
546 return dev->driver->prime_handle_to_fd(dev, file_priv,
547 args->handle, args->flags,
548 &args->fd);
549 }
550 return drm_gem_prime_handle_to_fd(dev, file_priv, args->handle,
551 args->flags, &args->fd);
552}
553
554/**
555 * DOC: PRIME Helpers
556 *
557 * Drivers can implement &drm_gem_object_funcs.export and
558 * &drm_driver.gem_prime_import in terms of simpler APIs by using the helper
559 * functions drm_gem_prime_export() and drm_gem_prime_import(). These functions
560 * implement dma-buf support in terms of some lower-level helpers, which are
561 * again exported for drivers to use individually:
562 *
563 * Exporting buffers
564 * ~~~~~~~~~~~~~~~~~
565 *
566 * Optional pinning of buffers is handled at dma-buf attach and detach time in
567 * drm_gem_map_attach() and drm_gem_map_detach(). Backing storage itself is
568 * handled by drm_gem_map_dma_buf() and drm_gem_unmap_dma_buf(), which relies on
569 * &drm_gem_object_funcs.get_sg_table. If &drm_gem_object_funcs.get_sg_table is
570 * unimplemented, exports into another device are rejected.
571 *
572 * For kernel-internal access there's drm_gem_dmabuf_vmap() and
573 * drm_gem_dmabuf_vunmap(). Userspace mmap support is provided by
574 * drm_gem_dmabuf_mmap().
575 *
576 * Note that these export helpers can only be used if the underlying backing
577 * storage is fully coherent and either permanently pinned, or it is safe to pin
578 * it indefinitely.
579 *
580 * FIXME: The underlying helper functions are named rather inconsistently.
581 *
582 * Importing buffers
583 * ~~~~~~~~~~~~~~~~~
584 *
585 * Importing dma-bufs using drm_gem_prime_import() relies on
586 * &drm_driver.gem_prime_import_sg_table.
587 *
588 * Note that similarly to the export helpers this permanently pins the
589 * underlying backing storage. Which is ok for scanout, but is not the best
590 * option for sharing lots of buffers for rendering.
591 */
592
593/**
594 * drm_gem_map_attach - dma_buf attach implementation for GEM
595 * @dma_buf: buffer to attach device to
596 * @attach: buffer attachment data
597 *
598 * Calls &drm_gem_object_funcs.pin for device specific handling. This can be
599 * used as the &dma_buf_ops.attach callback. Must be used together with
600 * drm_gem_map_detach().
601 *
602 * Returns 0 on success, negative error code on failure.
603 */
604int drm_gem_map_attach(struct dma_buf *dma_buf,
605 struct dma_buf_attachment *attach)
606{
607 struct drm_gem_object *obj = dma_buf->priv;
608
609 /*
610 * drm_gem_map_dma_buf() requires obj->get_sg_table(), but drivers
611 * that implement their own ->map_dma_buf() do not.
612 */
613 if (dma_buf->ops->map_dma_buf == drm_gem_map_dma_buf &&
614 !obj->funcs->get_sg_table)
615 return -ENOSYS;
616
617 return drm_gem_pin(obj);
618}
619EXPORT_SYMBOL(drm_gem_map_attach);
620
621/**
622 * drm_gem_map_detach - dma_buf detach implementation for GEM
623 * @dma_buf: buffer to detach from
624 * @attach: attachment to be detached
625 *
626 * Calls &drm_gem_object_funcs.pin for device specific handling. Cleans up
627 * &dma_buf_attachment from drm_gem_map_attach(). This can be used as the
628 * &dma_buf_ops.detach callback.
629 */
630void drm_gem_map_detach(struct dma_buf *dma_buf,
631 struct dma_buf_attachment *attach)
632{
633 struct drm_gem_object *obj = dma_buf->priv;
634
635 drm_gem_unpin(obj);
636}
637EXPORT_SYMBOL(drm_gem_map_detach);
638
639/**
640 * drm_gem_map_dma_buf - map_dma_buf implementation for GEM
641 * @attach: attachment whose scatterlist is to be returned
642 * @dir: direction of DMA transfer
643 *
644 * Calls &drm_gem_object_funcs.get_sg_table and then maps the scatterlist. This
645 * can be used as the &dma_buf_ops.map_dma_buf callback. Should be used together
646 * with drm_gem_unmap_dma_buf().
647 *
648 * Returns:sg_table containing the scatterlist to be returned; returns ERR_PTR
649 * on error. May return -EINTR if it is interrupted by a signal.
650 */
651struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
652 enum dma_data_direction dir)
653{
654 struct drm_gem_object *obj = attach->dmabuf->priv;
655 struct sg_table *sgt;
656 int ret;
657
658 if (WARN_ON(dir == DMA_NONE))
659 return ERR_PTR(-EINVAL);
660
661 if (WARN_ON(!obj->funcs->get_sg_table))
662 return ERR_PTR(-ENOSYS);
663
664 sgt = obj->funcs->get_sg_table(obj);
665 if (IS_ERR(sgt))
666 return sgt;
667
668 ret = dma_map_sgtable(attach->dev, sgt, dir,
669 DMA_ATTR_SKIP_CPU_SYNC);
670 if (ret) {
671 sg_free_table(sgt);
672 kfree(sgt);
673 sgt = ERR_PTR(ret);
674 }
675
676 return sgt;
677}
678EXPORT_SYMBOL(drm_gem_map_dma_buf);
679
680/**
681 * drm_gem_unmap_dma_buf - unmap_dma_buf implementation for GEM
682 * @attach: attachment to unmap buffer from
683 * @sgt: scatterlist info of the buffer to unmap
684 * @dir: direction of DMA transfer
685 *
686 * This can be used as the &dma_buf_ops.unmap_dma_buf callback.
687 */
688void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
689 struct sg_table *sgt,
690 enum dma_data_direction dir)
691{
692 if (!sgt)
693 return;
694
695 dma_unmap_sgtable(attach->dev, sgt, dir, DMA_ATTR_SKIP_CPU_SYNC);
696 sg_free_table(sgt);
697 kfree(sgt);
698}
699EXPORT_SYMBOL(drm_gem_unmap_dma_buf);
700
701/**
702 * drm_gem_dmabuf_vmap - dma_buf vmap implementation for GEM
703 * @dma_buf: buffer to be mapped
704 * @map: the virtual address of the buffer
705 *
706 * Sets up a kernel virtual mapping. This can be used as the &dma_buf_ops.vmap
707 * callback. Calls into &drm_gem_object_funcs.vmap for device specific handling.
708 * The kernel virtual address is returned in map.
709 *
710 * Returns 0 on success or a negative errno code otherwise.
711 */
712int drm_gem_dmabuf_vmap(struct dma_buf *dma_buf, struct iosys_map *map)
713{
714 struct drm_gem_object *obj = dma_buf->priv;
715
716 return drm_gem_vmap(obj, map);
717}
718EXPORT_SYMBOL(drm_gem_dmabuf_vmap);
719
720/**
721 * drm_gem_dmabuf_vunmap - dma_buf vunmap implementation for GEM
722 * @dma_buf: buffer to be unmapped
723 * @map: the virtual address of the buffer
724 *
725 * Releases a kernel virtual mapping. This can be used as the
726 * &dma_buf_ops.vunmap callback. Calls into &drm_gem_object_funcs.vunmap for device specific handling.
727 */
728void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, struct iosys_map *map)
729{
730 struct drm_gem_object *obj = dma_buf->priv;
731
732 drm_gem_vunmap(obj, map);
733}
734EXPORT_SYMBOL(drm_gem_dmabuf_vunmap);
735
736/**
737 * drm_gem_prime_mmap - PRIME mmap function for GEM drivers
738 * @obj: GEM object
739 * @vma: Virtual address range
740 *
741 * This function sets up a userspace mapping for PRIME exported buffers using
742 * the same codepath that is used for regular GEM buffer mapping on the DRM fd.
743 * The fake GEM offset is added to vma->vm_pgoff and &drm_driver->fops->mmap is
744 * called to set up the mapping.
745 */
746int drm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
747{
748 struct drm_file *priv;
749 struct file *fil;
750 int ret;
751
752 /* Add the fake offset */
753 vma->vm_pgoff += drm_vma_node_start(&obj->vma_node);
754
755 if (obj->funcs && obj->funcs->mmap) {
756 vma->vm_ops = obj->funcs->vm_ops;
757
758 drm_gem_object_get(obj);
759 ret = obj->funcs->mmap(obj, vma);
760 if (ret) {
761 drm_gem_object_put(obj);
762 return ret;
763 }
764 vma->vm_private_data = obj;
765 return 0;
766 }
767
768 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
769 fil = kzalloc(sizeof(*fil), GFP_KERNEL);
770 if (!priv || !fil) {
771 ret = -ENOMEM;
772 goto out;
773 }
774
775 /* Used by drm_gem_mmap() to lookup the GEM object */
776 priv->minor = obj->dev->primary;
777 fil->private_data = priv;
778
779 ret = drm_vma_node_allow(&obj->vma_node, priv);
780 if (ret)
781 goto out;
782
783 ret = obj->dev->driver->fops->mmap(fil, vma);
784
785 drm_vma_node_revoke(&obj->vma_node, priv);
786out:
787 kfree(priv);
788 kfree(fil);
789
790 return ret;
791}
792EXPORT_SYMBOL(drm_gem_prime_mmap);
793
794/**
795 * drm_gem_dmabuf_mmap - dma_buf mmap implementation for GEM
796 * @dma_buf: buffer to be mapped
797 * @vma: virtual address range
798 *
799 * Provides memory mapping for the buffer. This can be used as the
800 * &dma_buf_ops.mmap callback. It just forwards to drm_gem_prime_mmap().
801 *
802 * Returns 0 on success or a negative error code on failure.
803 */
804int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
805{
806 struct drm_gem_object *obj = dma_buf->priv;
807
808 return drm_gem_prime_mmap(obj, vma);
809}
810EXPORT_SYMBOL(drm_gem_dmabuf_mmap);
811
812static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
813 .cache_sgt_mapping = true,
814 .attach = drm_gem_map_attach,
815 .detach = drm_gem_map_detach,
816 .map_dma_buf = drm_gem_map_dma_buf,
817 .unmap_dma_buf = drm_gem_unmap_dma_buf,
818 .release = drm_gem_dmabuf_release,
819 .mmap = drm_gem_dmabuf_mmap,
820 .vmap = drm_gem_dmabuf_vmap,
821 .vunmap = drm_gem_dmabuf_vunmap,
822};
823
824/**
825 * drm_prime_pages_to_sg - converts a page array into an sg list
826 * @dev: DRM device
827 * @pages: pointer to the array of page pointers to convert
828 * @nr_pages: length of the page vector
829 *
830 * This helper creates an sg table object from a set of pages
831 * the driver is responsible for mapping the pages into the
832 * importers address space for use with dma_buf itself.
833 *
834 * This is useful for implementing &drm_gem_object_funcs.get_sg_table.
835 */
836struct sg_table *drm_prime_pages_to_sg(struct drm_device *dev,
837 struct page **pages, unsigned int nr_pages)
838{
839 struct sg_table *sg;
840 size_t max_segment = 0;
841 int err;
842
843 sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
844 if (!sg)
845 return ERR_PTR(-ENOMEM);
846
847 if (dev)
848 max_segment = dma_max_mapping_size(dev->dev);
849 if (max_segment == 0)
850 max_segment = UINT_MAX;
851 err = sg_alloc_table_from_pages_segment(sg, pages, nr_pages, 0,
852 (unsigned long)nr_pages << PAGE_SHIFT,
853 max_segment, GFP_KERNEL);
854 if (err) {
855 kfree(sg);
856 sg = ERR_PTR(err);
857 }
858 return sg;
859}
860EXPORT_SYMBOL(drm_prime_pages_to_sg);
861
862/**
863 * drm_prime_get_contiguous_size - returns the contiguous size of the buffer
864 * @sgt: sg_table describing the buffer to check
865 *
866 * This helper calculates the contiguous size in the DMA address space
867 * of the buffer described by the provided sg_table.
868 *
869 * This is useful for implementing
870 * &drm_gem_object_funcs.gem_prime_import_sg_table.
871 */
872unsigned long drm_prime_get_contiguous_size(struct sg_table *sgt)
873{
874 dma_addr_t expected = sg_dma_address(sgt->sgl);
875 struct scatterlist *sg;
876 unsigned long size = 0;
877 int i;
878
879 for_each_sgtable_dma_sg(sgt, sg, i) {
880 unsigned int len = sg_dma_len(sg);
881
882 if (!len)
883 break;
884 if (sg_dma_address(sg) != expected)
885 break;
886 expected += len;
887 size += len;
888 }
889 return size;
890}
891EXPORT_SYMBOL(drm_prime_get_contiguous_size);
892
893/**
894 * drm_gem_prime_export - helper library implementation of the export callback
895 * @obj: GEM object to export
896 * @flags: flags like DRM_CLOEXEC and DRM_RDWR
897 *
898 * This is the implementation of the &drm_gem_object_funcs.export functions for GEM drivers
899 * using the PRIME helpers. It is used as the default in
900 * drm_gem_prime_handle_to_fd().
901 */
902struct dma_buf *drm_gem_prime_export(struct drm_gem_object *obj,
903 int flags)
904{
905 struct drm_device *dev = obj->dev;
906 struct dma_buf_export_info exp_info = {
907 .exp_name = KBUILD_MODNAME, /* white lie for debug */
908 .owner = dev->driver->fops->owner,
909 .ops = &drm_gem_prime_dmabuf_ops,
910 .size = obj->size,
911 .flags = flags,
912 .priv = obj,
913 .resv = obj->resv,
914 };
915
916 return drm_gem_dmabuf_export(dev, &exp_info);
917}
918EXPORT_SYMBOL(drm_gem_prime_export);
919
920/**
921 * drm_gem_prime_import_dev - core implementation of the import callback
922 * @dev: drm_device to import into
923 * @dma_buf: dma-buf object to import
924 * @attach_dev: struct device to dma_buf attach
925 *
926 * This is the core of drm_gem_prime_import(). It's designed to be called by
927 * drivers who want to use a different device structure than &drm_device.dev for
928 * attaching via dma_buf. This function calls
929 * &drm_driver.gem_prime_import_sg_table internally.
930 *
931 * Drivers must arrange to call drm_prime_gem_destroy() from their
932 * &drm_gem_object_funcs.free hook when using this function.
933 */
934struct drm_gem_object *drm_gem_prime_import_dev(struct drm_device *dev,
935 struct dma_buf *dma_buf,
936 struct device *attach_dev)
937{
938 struct dma_buf_attachment *attach;
939 struct sg_table *sgt;
940 struct drm_gem_object *obj;
941 int ret;
942
943 if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
944 obj = dma_buf->priv;
945 if (obj->dev == dev) {
946 /*
947 * Importing dmabuf exported from our own gem increases
948 * refcount on gem itself instead of f_count of dmabuf.
949 */
950 drm_gem_object_get(obj);
951 return obj;
952 }
953 }
954
955 if (!dev->driver->gem_prime_import_sg_table)
956 return ERR_PTR(-EINVAL);
957
958 attach = dma_buf_attach(dma_buf, attach_dev);
959 if (IS_ERR(attach))
960 return ERR_CAST(attach);
961
962 get_dma_buf(dma_buf);
963
964 sgt = dma_buf_map_attachment_unlocked(attach, DMA_BIDIRECTIONAL);
965 if (IS_ERR(sgt)) {
966 ret = PTR_ERR(sgt);
967 goto fail_detach;
968 }
969
970 obj = dev->driver->gem_prime_import_sg_table(dev, attach, sgt);
971 if (IS_ERR(obj)) {
972 ret = PTR_ERR(obj);
973 goto fail_unmap;
974 }
975
976 obj->import_attach = attach;
977 obj->resv = dma_buf->resv;
978
979 return obj;
980
981fail_unmap:
982 dma_buf_unmap_attachment_unlocked(attach, sgt, DMA_BIDIRECTIONAL);
983fail_detach:
984 dma_buf_detach(dma_buf, attach);
985 dma_buf_put(dma_buf);
986
987 return ERR_PTR(ret);
988}
989EXPORT_SYMBOL(drm_gem_prime_import_dev);
990
991/**
992 * drm_gem_prime_import - helper library implementation of the import callback
993 * @dev: drm_device to import into
994 * @dma_buf: dma-buf object to import
995 *
996 * This is the implementation of the gem_prime_import functions for GEM drivers
997 * using the PRIME helpers. Drivers can use this as their
998 * &drm_driver.gem_prime_import implementation. It is used as the default
999 * implementation in drm_gem_prime_fd_to_handle().
1000 *
1001 * Drivers must arrange to call drm_prime_gem_destroy() from their
1002 * &drm_gem_object_funcs.free hook when using this function.
1003 */
1004struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
1005 struct dma_buf *dma_buf)
1006{
1007 return drm_gem_prime_import_dev(dev, dma_buf, dev->dev);
1008}
1009EXPORT_SYMBOL(drm_gem_prime_import);
1010
1011/**
1012 * drm_prime_sg_to_page_array - convert an sg table into a page array
1013 * @sgt: scatter-gather table to convert
1014 * @pages: array of page pointers to store the pages in
1015 * @max_entries: size of the passed-in array
1016 *
1017 * Exports an sg table into an array of pages.
1018 *
1019 * This function is deprecated and strongly discouraged to be used.
1020 * The page array is only useful for page faults and those can corrupt fields
1021 * in the struct page if they are not handled by the exporting driver.
1022 */
1023int __deprecated drm_prime_sg_to_page_array(struct sg_table *sgt,
1024 struct page **pages,
1025 int max_entries)
1026{
1027 struct sg_page_iter page_iter;
1028 struct page **p = pages;
1029
1030 for_each_sgtable_page(sgt, &page_iter, 0) {
1031 if (WARN_ON(p - pages >= max_entries))
1032 return -1;
1033 *p++ = sg_page_iter_page(&page_iter);
1034 }
1035 return 0;
1036}
1037EXPORT_SYMBOL(drm_prime_sg_to_page_array);
1038
1039/**
1040 * drm_prime_sg_to_dma_addr_array - convert an sg table into a dma addr array
1041 * @sgt: scatter-gather table to convert
1042 * @addrs: array to store the dma bus address of each page
1043 * @max_entries: size of both the passed-in arrays
1044 *
1045 * Exports an sg table into an array of addresses.
1046 *
1047 * Drivers should use this in their &drm_driver.gem_prime_import_sg_table
1048 * implementation.
1049 */
1050int drm_prime_sg_to_dma_addr_array(struct sg_table *sgt, dma_addr_t *addrs,
1051 int max_entries)
1052{
1053 struct sg_dma_page_iter dma_iter;
1054 dma_addr_t *a = addrs;
1055
1056 for_each_sgtable_dma_page(sgt, &dma_iter, 0) {
1057 if (WARN_ON(a - addrs >= max_entries))
1058 return -1;
1059 *a++ = sg_page_iter_dma_address(&dma_iter);
1060 }
1061 return 0;
1062}
1063EXPORT_SYMBOL(drm_prime_sg_to_dma_addr_array);
1064
1065/**
1066 * drm_prime_gem_destroy - helper to clean up a PRIME-imported GEM object
1067 * @obj: GEM object which was created from a dma-buf
1068 * @sg: the sg-table which was pinned at import time
1069 *
1070 * This is the cleanup functions which GEM drivers need to call when they use
1071 * drm_gem_prime_import() or drm_gem_prime_import_dev() to import dma-bufs.
1072 */
1073void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
1074{
1075 struct dma_buf_attachment *attach;
1076 struct dma_buf *dma_buf;
1077
1078 attach = obj->import_attach;
1079 if (sg)
1080 dma_buf_unmap_attachment_unlocked(attach, sg, DMA_BIDIRECTIONAL);
1081 dma_buf = attach->dmabuf;
1082 dma_buf_detach(attach->dmabuf, attach);
1083 /* remove the reference */
1084 dma_buf_put(dma_buf);
1085}
1086EXPORT_SYMBOL(drm_prime_gem_destroy);