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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_fd - 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 * @prime_fd: pointer to storage for the fd id of the create dma-buf
419 *
420 * This is the PRIME export function which must be used mandatorily by GEM
421 * drivers to ensure correct lifetime management of the underlying GEM object.
422 * The actual exporting from GEM object to a dma-buf is done through the
423 * &drm_gem_object_funcs.export callback.
424 */
425int drm_gem_prime_handle_to_fd(struct drm_device *dev,
426 struct drm_file *file_priv, uint32_t handle,
427 uint32_t flags,
428 int *prime_fd)
429{
430 struct drm_gem_object *obj;
431 int ret = 0;
432 struct dma_buf *dmabuf;
433
434 mutex_lock(&file_priv->prime.lock);
435 obj = drm_gem_object_lookup(file_priv, handle);
436 if (!obj) {
437 ret = -ENOENT;
438 goto out_unlock;
439 }
440
441 dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle);
442 if (dmabuf) {
443 get_dma_buf(dmabuf);
444 goto out_have_handle;
445 }
446
447 mutex_lock(&dev->object_name_lock);
448 /* re-export the original imported object */
449 if (obj->import_attach) {
450 dmabuf = obj->import_attach->dmabuf;
451 get_dma_buf(dmabuf);
452 goto out_have_obj;
453 }
454
455 if (obj->dma_buf) {
456 get_dma_buf(obj->dma_buf);
457 dmabuf = obj->dma_buf;
458 goto out_have_obj;
459 }
460
461 dmabuf = export_and_register_object(dev, obj, flags);
462 if (IS_ERR(dmabuf)) {
463 /* normally the created dma-buf takes ownership of the ref,
464 * but if that fails then drop the ref
465 */
466 ret = PTR_ERR(dmabuf);
467 mutex_unlock(&dev->object_name_lock);
468 goto out;
469 }
470
471out_have_obj:
472 /*
473 * If we've exported this buffer then cheat and add it to the import list
474 * so we get the correct handle back. We must do this under the
475 * protection of dev->object_name_lock to ensure that a racing gem close
476 * ioctl doesn't miss to remove this buffer handle from the cache.
477 */
478 ret = drm_prime_add_buf_handle(&file_priv->prime,
479 dmabuf, handle);
480 mutex_unlock(&dev->object_name_lock);
481 if (ret)
482 goto fail_put_dmabuf;
483
484out_have_handle:
485 ret = dma_buf_fd(dmabuf, flags);
486 /*
487 * We must _not_ remove the buffer from the handle cache since the newly
488 * created dma buf is already linked in the global obj->dma_buf pointer,
489 * and that is invariant as long as a userspace gem handle exists.
490 * Closing the handle will clean out the cache anyway, so we don't leak.
491 */
492 if (ret < 0) {
493 goto fail_put_dmabuf;
494 } else {
495 *prime_fd = ret;
496 ret = 0;
497 }
498
499 goto out;
500
501fail_put_dmabuf:
502 dma_buf_put(dmabuf);
503out:
504 drm_gem_object_put(obj);
505out_unlock:
506 mutex_unlock(&file_priv->prime.lock);
507
508 return ret;
509}
510EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
511
512int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
513 struct drm_file *file_priv)
514{
515 struct drm_prime_handle *args = data;
516
517 /* check flags are valid */
518 if (args->flags & ~(DRM_CLOEXEC | DRM_RDWR))
519 return -EINVAL;
520
521 if (dev->driver->prime_handle_to_fd) {
522 return dev->driver->prime_handle_to_fd(dev, file_priv,
523 args->handle, args->flags,
524 &args->fd);
525 }
526 return drm_gem_prime_handle_to_fd(dev, file_priv, args->handle,
527 args->flags, &args->fd);
528}
529
530/**
531 * DOC: PRIME Helpers
532 *
533 * Drivers can implement &drm_gem_object_funcs.export and
534 * &drm_driver.gem_prime_import in terms of simpler APIs by using the helper
535 * functions drm_gem_prime_export() and drm_gem_prime_import(). These functions
536 * implement dma-buf support in terms of some lower-level helpers, which are
537 * again exported for drivers to use individually:
538 *
539 * Exporting buffers
540 * ~~~~~~~~~~~~~~~~~
541 *
542 * Optional pinning of buffers is handled at dma-buf attach and detach time in
543 * drm_gem_map_attach() and drm_gem_map_detach(). Backing storage itself is
544 * handled by drm_gem_map_dma_buf() and drm_gem_unmap_dma_buf(), which relies on
545 * &drm_gem_object_funcs.get_sg_table. If &drm_gem_object_funcs.get_sg_table is
546 * unimplemented, exports into another device are rejected.
547 *
548 * For kernel-internal access there's drm_gem_dmabuf_vmap() and
549 * drm_gem_dmabuf_vunmap(). Userspace mmap support is provided by
550 * drm_gem_dmabuf_mmap().
551 *
552 * Note that these export helpers can only be used if the underlying backing
553 * storage is fully coherent and either permanently pinned, or it is safe to pin
554 * it indefinitely.
555 *
556 * FIXME: The underlying helper functions are named rather inconsistently.
557 *
558 * Importing buffers
559 * ~~~~~~~~~~~~~~~~~
560 *
561 * Importing dma-bufs using drm_gem_prime_import() relies on
562 * &drm_driver.gem_prime_import_sg_table.
563 *
564 * Note that similarly to the export helpers this permanently pins the
565 * underlying backing storage. Which is ok for scanout, but is not the best
566 * option for sharing lots of buffers for rendering.
567 */
568
569/**
570 * drm_gem_map_attach - dma_buf attach implementation for GEM
571 * @dma_buf: buffer to attach device to
572 * @attach: buffer attachment data
573 *
574 * Calls &drm_gem_object_funcs.pin for device specific handling. This can be
575 * used as the &dma_buf_ops.attach callback. Must be used together with
576 * drm_gem_map_detach().
577 *
578 * Returns 0 on success, negative error code on failure.
579 */
580int drm_gem_map_attach(struct dma_buf *dma_buf,
581 struct dma_buf_attachment *attach)
582{
583 struct drm_gem_object *obj = dma_buf->priv;
584
585 if (!obj->funcs->get_sg_table)
586 return -ENOSYS;
587
588 return drm_gem_pin(obj);
589}
590EXPORT_SYMBOL(drm_gem_map_attach);
591
592/**
593 * drm_gem_map_detach - dma_buf detach implementation for GEM
594 * @dma_buf: buffer to detach from
595 * @attach: attachment to be detached
596 *
597 * Calls &drm_gem_object_funcs.pin for device specific handling. Cleans up
598 * &dma_buf_attachment from drm_gem_map_attach(). This can be used as the
599 * &dma_buf_ops.detach callback.
600 */
601void drm_gem_map_detach(struct dma_buf *dma_buf,
602 struct dma_buf_attachment *attach)
603{
604 struct drm_gem_object *obj = dma_buf->priv;
605
606 drm_gem_unpin(obj);
607}
608EXPORT_SYMBOL(drm_gem_map_detach);
609
610/**
611 * drm_gem_map_dma_buf - map_dma_buf implementation for GEM
612 * @attach: attachment whose scatterlist is to be returned
613 * @dir: direction of DMA transfer
614 *
615 * Calls &drm_gem_object_funcs.get_sg_table and then maps the scatterlist. This
616 * can be used as the &dma_buf_ops.map_dma_buf callback. Should be used together
617 * with drm_gem_unmap_dma_buf().
618 *
619 * Returns:sg_table containing the scatterlist to be returned; returns ERR_PTR
620 * on error. May return -EINTR if it is interrupted by a signal.
621 */
622struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
623 enum dma_data_direction dir)
624{
625 struct drm_gem_object *obj = attach->dmabuf->priv;
626 struct sg_table *sgt;
627 int ret;
628
629 if (WARN_ON(dir == DMA_NONE))
630 return ERR_PTR(-EINVAL);
631
632 if (WARN_ON(!obj->funcs->get_sg_table))
633 return ERR_PTR(-ENOSYS);
634
635 sgt = obj->funcs->get_sg_table(obj);
636 if (IS_ERR(sgt))
637 return sgt;
638
639 ret = dma_map_sgtable(attach->dev, sgt, dir,
640 DMA_ATTR_SKIP_CPU_SYNC);
641 if (ret) {
642 sg_free_table(sgt);
643 kfree(sgt);
644 sgt = ERR_PTR(ret);
645 }
646
647 return sgt;
648}
649EXPORT_SYMBOL(drm_gem_map_dma_buf);
650
651/**
652 * drm_gem_unmap_dma_buf - unmap_dma_buf implementation for GEM
653 * @attach: attachment to unmap buffer from
654 * @sgt: scatterlist info of the buffer to unmap
655 * @dir: direction of DMA transfer
656 *
657 * This can be used as the &dma_buf_ops.unmap_dma_buf callback.
658 */
659void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
660 struct sg_table *sgt,
661 enum dma_data_direction dir)
662{
663 if (!sgt)
664 return;
665
666 dma_unmap_sgtable(attach->dev, sgt, dir, DMA_ATTR_SKIP_CPU_SYNC);
667 sg_free_table(sgt);
668 kfree(sgt);
669}
670EXPORT_SYMBOL(drm_gem_unmap_dma_buf);
671
672/**
673 * drm_gem_dmabuf_vmap - dma_buf vmap implementation for GEM
674 * @dma_buf: buffer to be mapped
675 * @map: the virtual address of the buffer
676 *
677 * Sets up a kernel virtual mapping. This can be used as the &dma_buf_ops.vmap
678 * callback. Calls into &drm_gem_object_funcs.vmap for device specific handling.
679 * The kernel virtual address is returned in map.
680 *
681 * Returns 0 on success or a negative errno code otherwise.
682 */
683int drm_gem_dmabuf_vmap(struct dma_buf *dma_buf, struct iosys_map *map)
684{
685 struct drm_gem_object *obj = dma_buf->priv;
686
687 return drm_gem_vmap(obj, map);
688}
689EXPORT_SYMBOL(drm_gem_dmabuf_vmap);
690
691/**
692 * drm_gem_dmabuf_vunmap - dma_buf vunmap implementation for GEM
693 * @dma_buf: buffer to be unmapped
694 * @map: the virtual address of the buffer
695 *
696 * Releases a kernel virtual mapping. This can be used as the
697 * &dma_buf_ops.vunmap callback. Calls into &drm_gem_object_funcs.vunmap for device specific handling.
698 */
699void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, struct iosys_map *map)
700{
701 struct drm_gem_object *obj = dma_buf->priv;
702
703 drm_gem_vunmap(obj, map);
704}
705EXPORT_SYMBOL(drm_gem_dmabuf_vunmap);
706
707/**
708 * drm_gem_prime_mmap - PRIME mmap function for GEM drivers
709 * @obj: GEM object
710 * @vma: Virtual address range
711 *
712 * This function sets up a userspace mapping for PRIME exported buffers using
713 * the same codepath that is used for regular GEM buffer mapping on the DRM fd.
714 * The fake GEM offset is added to vma->vm_pgoff and &drm_driver->fops->mmap is
715 * called to set up the mapping.
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_gem_prime_mmap().
772 *
773 * Returns 0 on success or a negative error code on failure.
774 */
775int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
776{
777 struct drm_gem_object *obj = dma_buf->priv;
778
779 return drm_gem_prime_mmap(obj, vma);
780}
781EXPORT_SYMBOL(drm_gem_dmabuf_mmap);
782
783static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
784 .cache_sgt_mapping = true,
785 .attach = drm_gem_map_attach,
786 .detach = drm_gem_map_detach,
787 .map_dma_buf = drm_gem_map_dma_buf,
788 .unmap_dma_buf = drm_gem_unmap_dma_buf,
789 .release = drm_gem_dmabuf_release,
790 .mmap = drm_gem_dmabuf_mmap,
791 .vmap = drm_gem_dmabuf_vmap,
792 .vunmap = drm_gem_dmabuf_vunmap,
793};
794
795/**
796 * drm_prime_pages_to_sg - converts a page array into an sg list
797 * @dev: DRM device
798 * @pages: pointer to the array of page pointers to convert
799 * @nr_pages: length of the page vector
800 *
801 * This helper creates an sg table object from a set of pages
802 * the driver is responsible for mapping the pages into the
803 * importers address space for use with dma_buf itself.
804 *
805 * This is useful for implementing &drm_gem_object_funcs.get_sg_table.
806 */
807struct sg_table *drm_prime_pages_to_sg(struct drm_device *dev,
808 struct page **pages, unsigned int nr_pages)
809{
810 struct sg_table *sg;
811 size_t max_segment = 0;
812 int err;
813
814 sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
815 if (!sg)
816 return ERR_PTR(-ENOMEM);
817
818 if (dev)
819 max_segment = dma_max_mapping_size(dev->dev);
820 if (max_segment == 0)
821 max_segment = UINT_MAX;
822 err = sg_alloc_table_from_pages_segment(sg, pages, nr_pages, 0,
823 (unsigned long)nr_pages << PAGE_SHIFT,
824 max_segment, GFP_KERNEL);
825 if (err) {
826 kfree(sg);
827 sg = ERR_PTR(err);
828 }
829 return sg;
830}
831EXPORT_SYMBOL(drm_prime_pages_to_sg);
832
833/**
834 * drm_prime_get_contiguous_size - returns the contiguous size of the buffer
835 * @sgt: sg_table describing the buffer to check
836 *
837 * This helper calculates the contiguous size in the DMA address space
838 * of the buffer described by the provided sg_table.
839 *
840 * This is useful for implementing
841 * &drm_gem_object_funcs.gem_prime_import_sg_table.
842 */
843unsigned long drm_prime_get_contiguous_size(struct sg_table *sgt)
844{
845 dma_addr_t expected = sg_dma_address(sgt->sgl);
846 struct scatterlist *sg;
847 unsigned long size = 0;
848 int i;
849
850 for_each_sgtable_dma_sg(sgt, sg, i) {
851 unsigned int len = sg_dma_len(sg);
852
853 if (!len)
854 break;
855 if (sg_dma_address(sg) != expected)
856 break;
857 expected += len;
858 size += len;
859 }
860 return size;
861}
862EXPORT_SYMBOL(drm_prime_get_contiguous_size);
863
864/**
865 * drm_gem_prime_export - helper library implementation of the export callback
866 * @obj: GEM object to export
867 * @flags: flags like DRM_CLOEXEC and DRM_RDWR
868 *
869 * This is the implementation of the &drm_gem_object_funcs.export functions for GEM drivers
870 * using the PRIME helpers. It is used as the default in
871 * drm_gem_prime_handle_to_fd().
872 */
873struct dma_buf *drm_gem_prime_export(struct drm_gem_object *obj,
874 int flags)
875{
876 struct drm_device *dev = obj->dev;
877 struct dma_buf_export_info exp_info = {
878 .exp_name = KBUILD_MODNAME, /* white lie for debug */
879 .owner = dev->driver->fops->owner,
880 .ops = &drm_gem_prime_dmabuf_ops,
881 .size = obj->size,
882 .flags = flags,
883 .priv = obj,
884 .resv = obj->resv,
885 };
886
887 return drm_gem_dmabuf_export(dev, &exp_info);
888}
889EXPORT_SYMBOL(drm_gem_prime_export);
890
891/**
892 * drm_gem_prime_import_dev - core implementation of the import callback
893 * @dev: drm_device to import into
894 * @dma_buf: dma-buf object to import
895 * @attach_dev: struct device to dma_buf attach
896 *
897 * This is the core of drm_gem_prime_import(). It's designed to be called by
898 * drivers who want to use a different device structure than &drm_device.dev for
899 * attaching via dma_buf. This function calls
900 * &drm_driver.gem_prime_import_sg_table internally.
901 *
902 * Drivers must arrange to call drm_prime_gem_destroy() from their
903 * &drm_gem_object_funcs.free hook when using this function.
904 */
905struct drm_gem_object *drm_gem_prime_import_dev(struct drm_device *dev,
906 struct dma_buf *dma_buf,
907 struct device *attach_dev)
908{
909 struct dma_buf_attachment *attach;
910 struct sg_table *sgt;
911 struct drm_gem_object *obj;
912 int ret;
913
914 if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
915 obj = dma_buf->priv;
916 if (obj->dev == dev) {
917 /*
918 * Importing dmabuf exported from our own gem increases
919 * refcount on gem itself instead of f_count of dmabuf.
920 */
921 drm_gem_object_get(obj);
922 return obj;
923 }
924 }
925
926 if (!dev->driver->gem_prime_import_sg_table)
927 return ERR_PTR(-EINVAL);
928
929 attach = dma_buf_attach(dma_buf, attach_dev);
930 if (IS_ERR(attach))
931 return ERR_CAST(attach);
932
933 get_dma_buf(dma_buf);
934
935 sgt = dma_buf_map_attachment_unlocked(attach, DMA_BIDIRECTIONAL);
936 if (IS_ERR(sgt)) {
937 ret = PTR_ERR(sgt);
938 goto fail_detach;
939 }
940
941 obj = dev->driver->gem_prime_import_sg_table(dev, attach, sgt);
942 if (IS_ERR(obj)) {
943 ret = PTR_ERR(obj);
944 goto fail_unmap;
945 }
946
947 obj->import_attach = attach;
948 obj->resv = dma_buf->resv;
949
950 return obj;
951
952fail_unmap:
953 dma_buf_unmap_attachment_unlocked(attach, sgt, DMA_BIDIRECTIONAL);
954fail_detach:
955 dma_buf_detach(dma_buf, attach);
956 dma_buf_put(dma_buf);
957
958 return ERR_PTR(ret);
959}
960EXPORT_SYMBOL(drm_gem_prime_import_dev);
961
962/**
963 * drm_gem_prime_import - helper library implementation of the import callback
964 * @dev: drm_device to import into
965 * @dma_buf: dma-buf object to import
966 *
967 * This is the implementation of the gem_prime_import functions for GEM drivers
968 * using the PRIME helpers. Drivers can use this as their
969 * &drm_driver.gem_prime_import implementation. It is used as the default
970 * implementation in drm_gem_prime_fd_to_handle().
971 *
972 * Drivers must arrange to call drm_prime_gem_destroy() from their
973 * &drm_gem_object_funcs.free hook when using this function.
974 */
975struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
976 struct dma_buf *dma_buf)
977{
978 return drm_gem_prime_import_dev(dev, dma_buf, dev->dev);
979}
980EXPORT_SYMBOL(drm_gem_prime_import);
981
982/**
983 * drm_prime_sg_to_page_array - convert an sg table into a page array
984 * @sgt: scatter-gather table to convert
985 * @pages: array of page pointers to store the pages in
986 * @max_entries: size of the passed-in array
987 *
988 * Exports an sg table into an array of pages.
989 *
990 * This function is deprecated and strongly discouraged to be used.
991 * The page array is only useful for page faults and those can corrupt fields
992 * in the struct page if they are not handled by the exporting driver.
993 */
994int __deprecated drm_prime_sg_to_page_array(struct sg_table *sgt,
995 struct page **pages,
996 int max_entries)
997{
998 struct sg_page_iter page_iter;
999 struct page **p = pages;
1000
1001 for_each_sgtable_page(sgt, &page_iter, 0) {
1002 if (WARN_ON(p - pages >= max_entries))
1003 return -1;
1004 *p++ = sg_page_iter_page(&page_iter);
1005 }
1006 return 0;
1007}
1008EXPORT_SYMBOL(drm_prime_sg_to_page_array);
1009
1010/**
1011 * drm_prime_sg_to_dma_addr_array - convert an sg table into a dma addr array
1012 * @sgt: scatter-gather table to convert
1013 * @addrs: array to store the dma bus address of each page
1014 * @max_entries: size of both the passed-in arrays
1015 *
1016 * Exports an sg table into an array of addresses.
1017 *
1018 * Drivers should use this in their &drm_driver.gem_prime_import_sg_table
1019 * implementation.
1020 */
1021int drm_prime_sg_to_dma_addr_array(struct sg_table *sgt, dma_addr_t *addrs,
1022 int max_entries)
1023{
1024 struct sg_dma_page_iter dma_iter;
1025 dma_addr_t *a = addrs;
1026
1027 for_each_sgtable_dma_page(sgt, &dma_iter, 0) {
1028 if (WARN_ON(a - addrs >= max_entries))
1029 return -1;
1030 *a++ = sg_page_iter_dma_address(&dma_iter);
1031 }
1032 return 0;
1033}
1034EXPORT_SYMBOL(drm_prime_sg_to_dma_addr_array);
1035
1036/**
1037 * drm_prime_gem_destroy - helper to clean up a PRIME-imported GEM object
1038 * @obj: GEM object which was created from a dma-buf
1039 * @sg: the sg-table which was pinned at import time
1040 *
1041 * This is the cleanup functions which GEM drivers need to call when they use
1042 * drm_gem_prime_import() or drm_gem_prime_import_dev() to import dma-bufs.
1043 */
1044void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
1045{
1046 struct dma_buf_attachment *attach;
1047 struct dma_buf *dma_buf;
1048
1049 attach = obj->import_attach;
1050 if (sg)
1051 dma_buf_unmap_attachment_unlocked(attach, sg, DMA_BIDIRECTIONAL);
1052 dma_buf = attach->dmabuf;
1053 dma_buf_detach(attach->dmabuf, attach);
1054 /* remove the reference */
1055 dma_buf_put(dma_buf);
1056}
1057EXPORT_SYMBOL(drm_prime_gem_destroy);