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