drm_gem_shmem_helper.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright 2018 Noralf Trønnes
  4 */
  5
  6#include <linux/dma-buf.h>
  7#include <linux/export.h>
  8#include <linux/module.h>
  9#include <linux/mutex.h>
 10#include <linux/shmem_fs.h>
 11#include <linux/slab.h>
 12#include <linux/vmalloc.h>
 13
 14#ifdef CONFIG_X86
 15#include <asm/set_memory.h>
 16#endif
 17
 18#include <kunit/visibility.h>
 19
 20#include <drm/drm.h>
 21#include <drm/drm_device.h>
 22#include <drm/drm_drv.h>
 23#include <drm/drm_dumb_buffers.h>
 24#include <drm/drm_gem_shmem_helper.h>
 25#include <drm/drm_prime.h>
 26#include <drm/drm_print.h>
 27
 28MODULE_IMPORT_NS("DMA_BUF");
 29
 30/**
 31 * DOC: overview
 32 *
 33 * This library provides helpers for GEM objects backed by shmem buffers
 34 * allocated using anonymous pageable memory.
 35 *
 36 * Functions that operate on the GEM object receive struct &drm_gem_shmem_object.
 37 * For GEM callback helpers in struct &drm_gem_object functions, see likewise
 38 * named functions with an _object_ infix (e.g., drm_gem_shmem_object_vmap() wraps
 39 * drm_gem_shmem_vmap()). These helpers perform the necessary type conversion.
 40 */
 41
 42static const struct drm_gem_object_funcs drm_gem_shmem_funcs = {
 43	.free = drm_gem_shmem_object_free,
 44	.print_info = drm_gem_shmem_object_print_info,
 45	.pin = drm_gem_shmem_object_pin,
 46	.unpin = drm_gem_shmem_object_unpin,
 47	.get_sg_table = drm_gem_shmem_object_get_sg_table,
 48	.vmap = drm_gem_shmem_object_vmap,
 49	.vunmap = drm_gem_shmem_object_vunmap,
 50	.mmap = drm_gem_shmem_object_mmap,
 51	.vm_ops = &drm_gem_shmem_vm_ops,
 52};
 53
 54static int __drm_gem_shmem_init(struct drm_device *dev, struct drm_gem_shmem_object *shmem,
 55				size_t size, bool private, struct vfsmount *gemfs)
 56{
 57	struct drm_gem_object *obj = &shmem->base;
 58	int ret = 0;
 59
 60	if (!obj->funcs)
 61		obj->funcs = &drm_gem_shmem_funcs;
 62
 63	if (private) {
 64		drm_gem_private_object_init(dev, obj, size);
 65		shmem->map_wc = false; /* dma-buf mappings use always writecombine */
 66	} else {
 67		ret = drm_gem_object_init_with_mnt(dev, obj, size, gemfs);
 68	}
 69	if (ret) {
 70		drm_gem_private_object_fini(obj);
 71		return ret;
 72	}
 73
 74	ret = drm_gem_create_mmap_offset(obj);
 75	if (ret)
 76		goto err_release;
 77
 78	INIT_LIST_HEAD(&shmem->madv_list);
 79
 80	if (!private) {
 81		/*
 82		 * Our buffers are kept pinned, so allocating them
 83		 * from the MOVABLE zone is a really bad idea, and
 84		 * conflicts with CMA. See comments above new_inode()
 85		 * why this is required _and_ expected if you're
 86		 * going to pin these pages.
 87		 */
 88		mapping_set_gfp_mask(obj->filp->f_mapping, GFP_HIGHUSER |
 89				     __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
 90	}
 91
 92	return 0;
 93err_release:
 94	drm_gem_object_release(obj);
 95	return ret;
 96}
 97
 98/**
 99 * drm_gem_shmem_init - Initialize an allocated object.
100 * @dev: DRM device
101 * @shmem: The allocated shmem GEM object.
102 * @size: Buffer size in bytes
103 *
104 * Returns:
105 * 0 on success, or a negative error code on failure.
106 */
107int drm_gem_shmem_init(struct drm_device *dev, struct drm_gem_shmem_object *shmem, size_t size)
108{
109	return __drm_gem_shmem_init(dev, shmem, size, false, NULL);
110}
111EXPORT_SYMBOL_GPL(drm_gem_shmem_init);
112
113static struct drm_gem_shmem_object *
114__drm_gem_shmem_create(struct drm_device *dev, size_t size, bool private,
115		       struct vfsmount *gemfs)
116{
117	struct drm_gem_shmem_object *shmem;
118	struct drm_gem_object *obj;
119	int ret = 0;
120
121	size = PAGE_ALIGN(size);
122
123	if (dev->driver->gem_create_object) {
124		obj = dev->driver->gem_create_object(dev, size);
125		if (IS_ERR(obj))
126			return ERR_CAST(obj);
127		shmem = to_drm_gem_shmem_obj(obj);
128	} else {
129		shmem = kzalloc(sizeof(*shmem), GFP_KERNEL);
130		if (!shmem)
131			return ERR_PTR(-ENOMEM);
132		obj = &shmem->base;
133	}
134
135	ret = __drm_gem_shmem_init(dev, shmem, size, private, gemfs);
136	if (ret) {
137		kfree(obj);
138		return ERR_PTR(ret);
139	}
140
141	return shmem;
142}
143/**
144 * drm_gem_shmem_create - Allocate an object with the given size
145 * @dev: DRM device
146 * @size: Size of the object to allocate
147 *
148 * This function creates a shmem GEM object.
149 *
150 * Returns:
151 * A struct drm_gem_shmem_object * on success or an ERR_PTR()-encoded negative
152 * error code on failure.
153 */
154struct drm_gem_shmem_object *drm_gem_shmem_create(struct drm_device *dev, size_t size)
155{
156	return __drm_gem_shmem_create(dev, size, false, NULL);
157}
158EXPORT_SYMBOL_GPL(drm_gem_shmem_create);
159
160/**
161 * drm_gem_shmem_create_with_mnt - Allocate an object with the given size in a
162 * given mountpoint
163 * @dev: DRM device
164 * @size: Size of the object to allocate
165 * @gemfs: tmpfs mount where the GEM object will be created
166 *
167 * This function creates a shmem GEM object in a given tmpfs mountpoint.
168 *
169 * Returns:
170 * A struct drm_gem_shmem_object * on success or an ERR_PTR()-encoded negative
171 * error code on failure.
172 */
173struct drm_gem_shmem_object *drm_gem_shmem_create_with_mnt(struct drm_device *dev,
174							   size_t size,
175							   struct vfsmount *gemfs)
176{
177	return __drm_gem_shmem_create(dev, size, false, gemfs);
178}
179EXPORT_SYMBOL_GPL(drm_gem_shmem_create_with_mnt);
180
181/**
182 * drm_gem_shmem_release - Release resources associated with a shmem GEM object.
183 * @shmem: shmem GEM object
184 *
185 * This function cleans up the GEM object state, but does not free the memory used to store the
186 * object itself. This function is meant to be a dedicated helper for the Rust GEM bindings.
187 */
188void drm_gem_shmem_release(struct drm_gem_shmem_object *shmem)
189{
190	struct drm_gem_object *obj = &shmem->base;
191
192	if (drm_gem_is_imported(obj)) {
193		drm_prime_gem_destroy(obj, shmem->sgt);
194	} else {
195		dma_resv_lock(shmem->base.resv, NULL);
196
197		drm_WARN_ON(obj->dev, refcount_read(&shmem->vmap_use_count));
198
199		if (shmem->sgt) {
200			dma_unmap_sgtable(obj->dev->dev, shmem->sgt,
201					  DMA_BIDIRECTIONAL, 0);
202			sg_free_table(shmem->sgt);
203			kfree(shmem->sgt);
204		}
205		if (shmem->pages)
206			drm_gem_shmem_put_pages_locked(shmem);
207
208		drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_use_count));
209		drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_pin_count));
210
211		dma_resv_unlock(shmem->base.resv);
212	}
213
214	drm_gem_object_release(obj);
215}
216EXPORT_SYMBOL_GPL(drm_gem_shmem_release);
217
218/**
219 * drm_gem_shmem_free - Free resources associated with a shmem GEM object
220 * @shmem: shmem GEM object to free
221 *
222 * This function cleans up the GEM object state and frees the memory used to
223 * store the object itself.
224 */
225void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem)
226{
227	drm_gem_shmem_release(shmem);
228	kfree(shmem);
229}
230EXPORT_SYMBOL_GPL(drm_gem_shmem_free);
231
232static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem)
233{
234	struct drm_gem_object *obj = &shmem->base;
235	struct page **pages;
236
237	dma_resv_assert_held(shmem->base.resv);
238
239	if (refcount_inc_not_zero(&shmem->pages_use_count))
240		return 0;
241
242	pages = drm_gem_get_pages(obj);
243	if (IS_ERR(pages)) {
244		drm_dbg_kms(obj->dev, "Failed to get pages (%ld)\n",
245			    PTR_ERR(pages));
246		return PTR_ERR(pages);
247	}
248
249	/*
250	 * TODO: Allocating WC pages which are correctly flushed is only
251	 * supported on x86. Ideal solution would be a GFP_WC flag, which also
252	 * ttm_pool.c could use.
253	 */
254#ifdef CONFIG_X86
255	if (shmem->map_wc)
256		set_pages_array_wc(pages, obj->size >> PAGE_SHIFT);
257#endif
258
259	shmem->pages = pages;
260
261	refcount_set(&shmem->pages_use_count, 1);
262
263	return 0;
264}
265
266/*
267 * drm_gem_shmem_put_pages_locked - Decrease use count on the backing pages for a shmem GEM object
268 * @shmem: shmem GEM object
269 *
270 * This function decreases the use count and puts the backing pages when use drops to zero.
271 */
272void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem)
273{
274	struct drm_gem_object *obj = &shmem->base;
275
276	dma_resv_assert_held(shmem->base.resv);
277
278	if (refcount_dec_and_test(&shmem->pages_use_count)) {
279#ifdef CONFIG_X86
280		if (shmem->map_wc)
281			set_pages_array_wb(shmem->pages, obj->size >> PAGE_SHIFT);
282#endif
283
284		drm_gem_put_pages(obj, shmem->pages,
285				  shmem->pages_mark_dirty_on_put,
286				  shmem->pages_mark_accessed_on_put);
287		shmem->pages = NULL;
288	}
289}
290EXPORT_SYMBOL_GPL(drm_gem_shmem_put_pages_locked);
291
292int drm_gem_shmem_pin_locked(struct drm_gem_shmem_object *shmem)
293{
294	int ret;
295
296	dma_resv_assert_held(shmem->base.resv);
297
298	drm_WARN_ON(shmem->base.dev, drm_gem_is_imported(&shmem->base));
299
300	if (refcount_inc_not_zero(&shmem->pages_pin_count))
301		return 0;
302
303	ret = drm_gem_shmem_get_pages_locked(shmem);
304	if (!ret)
305		refcount_set(&shmem->pages_pin_count, 1);
306
307	return ret;
308}
309EXPORT_SYMBOL(drm_gem_shmem_pin_locked);
310
311void drm_gem_shmem_unpin_locked(struct drm_gem_shmem_object *shmem)
312{
313	dma_resv_assert_held(shmem->base.resv);
314
315	if (refcount_dec_and_test(&shmem->pages_pin_count))
316		drm_gem_shmem_put_pages_locked(shmem);
317}
318EXPORT_SYMBOL(drm_gem_shmem_unpin_locked);
319
320/**
321 * drm_gem_shmem_pin - Pin backing pages for a shmem GEM object
322 * @shmem: shmem GEM object
323 *
324 * This function makes sure the backing pages are pinned in memory while the
325 * buffer is exported.
326 *
327 * Returns:
328 * 0 on success or a negative error code on failure.
329 */
330int drm_gem_shmem_pin(struct drm_gem_shmem_object *shmem)
331{
332	struct drm_gem_object *obj = &shmem->base;
333	int ret;
334
335	drm_WARN_ON(obj->dev, drm_gem_is_imported(obj));
336
337	if (refcount_inc_not_zero(&shmem->pages_pin_count))
338		return 0;
339
340	ret = dma_resv_lock_interruptible(shmem->base.resv, NULL);
341	if (ret)
342		return ret;
343	ret = drm_gem_shmem_pin_locked(shmem);
344	dma_resv_unlock(shmem->base.resv);
345
346	return ret;
347}
348EXPORT_SYMBOL_GPL(drm_gem_shmem_pin);
349
350/**
351 * drm_gem_shmem_unpin - Unpin backing pages for a shmem GEM object
352 * @shmem: shmem GEM object
353 *
354 * This function removes the requirement that the backing pages are pinned in
355 * memory.
356 */
357void drm_gem_shmem_unpin(struct drm_gem_shmem_object *shmem)
358{
359	struct drm_gem_object *obj = &shmem->base;
360
361	drm_WARN_ON(obj->dev, drm_gem_is_imported(obj));
362
363	if (refcount_dec_not_one(&shmem->pages_pin_count))
364		return;
365
366	dma_resv_lock(shmem->base.resv, NULL);
367	drm_gem_shmem_unpin_locked(shmem);
368	dma_resv_unlock(shmem->base.resv);
369}
370EXPORT_SYMBOL_GPL(drm_gem_shmem_unpin);
371
372/*
373 * drm_gem_shmem_vmap_locked - Create a virtual mapping for a shmem GEM object
374 * @shmem: shmem GEM object
375 * @map: Returns the kernel virtual address of the SHMEM GEM object's backing
376 *       store.
377 *
378 * This function makes sure that a contiguous kernel virtual address mapping
379 * exists for the buffer backing the shmem GEM object. It hides the differences
380 * between dma-buf imported and natively allocated objects.
381 *
382 * Acquired mappings should be cleaned up by calling drm_gem_shmem_vunmap_locked().
383 *
384 * Returns:
385 * 0 on success or a negative error code on failure.
386 */
387int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem,
388			      struct iosys_map *map)
389{
390	struct drm_gem_object *obj = &shmem->base;
391	int ret = 0;
392
393	dma_resv_assert_held(obj->resv);
394
395	if (drm_gem_is_imported(obj)) {
396		ret = dma_buf_vmap(obj->import_attach->dmabuf, map);
397	} else {
398		pgprot_t prot = PAGE_KERNEL;
399
400		dma_resv_assert_held(shmem->base.resv);
401
402		if (refcount_inc_not_zero(&shmem->vmap_use_count)) {
403			iosys_map_set_vaddr(map, shmem->vaddr);
404			return 0;
405		}
406
407		ret = drm_gem_shmem_pin_locked(shmem);
408		if (ret)
409			return ret;
410
411		if (shmem->map_wc)
412			prot = pgprot_writecombine(prot);
413		shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT,
414				    VM_MAP, prot);
415		if (!shmem->vaddr) {
416			ret = -ENOMEM;
417		} else {
418			iosys_map_set_vaddr(map, shmem->vaddr);
419			refcount_set(&shmem->vmap_use_count, 1);
420		}
421	}
422
423	if (ret) {
424		drm_dbg_kms(obj->dev, "Failed to vmap pages, error %d\n", ret);
425		goto err_put_pages;
426	}
427
428	return 0;
429
430err_put_pages:
431	if (!drm_gem_is_imported(obj))
432		drm_gem_shmem_unpin_locked(shmem);
433
434	return ret;
435}
436EXPORT_SYMBOL_GPL(drm_gem_shmem_vmap_locked);
437
438/*
439 * drm_gem_shmem_vunmap_locked - Unmap a virtual mapping for a shmem GEM object
440 * @shmem: shmem GEM object
441 * @map: Kernel virtual address where the SHMEM GEM object was mapped
442 *
443 * This function cleans up a kernel virtual address mapping acquired by
444 * drm_gem_shmem_vmap_locked(). The mapping is only removed when the use count
445 * drops to zero.
446 *
447 * This function hides the differences between dma-buf imported and natively
448 * allocated objects.
449 */
450void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem,
451				 struct iosys_map *map)
452{
453	struct drm_gem_object *obj = &shmem->base;
454
455	dma_resv_assert_held(obj->resv);
456
457	if (drm_gem_is_imported(obj)) {
458		dma_buf_vunmap(obj->import_attach->dmabuf, map);
459	} else {
460		dma_resv_assert_held(shmem->base.resv);
461
462		if (refcount_dec_and_test(&shmem->vmap_use_count)) {
463			vunmap(shmem->vaddr);
464			shmem->vaddr = NULL;
465
466			drm_gem_shmem_unpin_locked(shmem);
467		}
468	}
469}
470EXPORT_SYMBOL_GPL(drm_gem_shmem_vunmap_locked);
471
472static int
473drm_gem_shmem_create_with_handle(struct drm_file *file_priv,
474				 struct drm_device *dev, size_t size,
475				 uint32_t *handle)
476{
477	struct drm_gem_shmem_object *shmem;
478	int ret;
479
480	shmem = drm_gem_shmem_create(dev, size);
481	if (IS_ERR(shmem))
482		return PTR_ERR(shmem);
483
484	/*
485	 * Allocate an id of idr table where the obj is registered
486	 * and handle has the id what user can see.
487	 */
488	ret = drm_gem_handle_create(file_priv, &shmem->base, handle);
489	/* drop reference from allocate - handle holds it now. */
490	drm_gem_object_put(&shmem->base);
491
492	return ret;
493}
494
495/* Update madvise status, returns true if not purged, else
496 * false or -errno.
497 */
498int drm_gem_shmem_madvise_locked(struct drm_gem_shmem_object *shmem, int madv)
499{
500	dma_resv_assert_held(shmem->base.resv);
501
502	if (shmem->madv >= 0)
503		shmem->madv = madv;
504
505	madv = shmem->madv;
506
507	return (madv >= 0);
508}
509EXPORT_SYMBOL_GPL(drm_gem_shmem_madvise_locked);
510
511void drm_gem_shmem_purge_locked(struct drm_gem_shmem_object *shmem)
512{
513	struct drm_gem_object *obj = &shmem->base;
514	struct drm_device *dev = obj->dev;
515
516	dma_resv_assert_held(shmem->base.resv);
517
518	drm_WARN_ON(obj->dev, !drm_gem_shmem_is_purgeable(shmem));
519
520	dma_unmap_sgtable(dev->dev, shmem->sgt, DMA_BIDIRECTIONAL, 0);
521	sg_free_table(shmem->sgt);
522	kfree(shmem->sgt);
523	shmem->sgt = NULL;
524
525	drm_gem_shmem_put_pages_locked(shmem);
526
527	shmem->madv = -1;
528
529	drm_vma_node_unmap(&obj->vma_node, dev->anon_inode->i_mapping);
530	drm_gem_free_mmap_offset(obj);
531
532	/* Our goal here is to return as much of the memory as
533	 * is possible back to the system as we are called from OOM.
534	 * To do this we must instruct the shmfs to drop all of its
535	 * backing pages, *now*.
536	 */
537	shmem_truncate_range(file_inode(obj->filp), 0, (loff_t)-1);
538
539	invalidate_mapping_pages(file_inode(obj->filp)->i_mapping, 0, (loff_t)-1);
540}
541EXPORT_SYMBOL_GPL(drm_gem_shmem_purge_locked);
542
543/**
544 * drm_gem_shmem_dumb_create - Create a dumb shmem buffer object
545 * @file: DRM file structure to create the dumb buffer for
546 * @dev: DRM device
547 * @args: IOCTL data
548 *
549 * This function computes the pitch of the dumb buffer and rounds it up to an
550 * integer number of bytes per pixel. Drivers for hardware that doesn't have
551 * any additional restrictions on the pitch can directly use this function as
552 * their &drm_driver.dumb_create callback.
553 *
554 * For hardware with additional restrictions, drivers can adjust the fields
555 * set up by userspace before calling into this function.
556 *
557 * Returns:
558 * 0 on success or a negative error code on failure.
559 */
560int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device *dev,
561			      struct drm_mode_create_dumb *args)
562{
563	int ret;
564
565	ret = drm_mode_size_dumb(dev, args, 0, 0);
566	if (ret)
567		return ret;
568
569	return drm_gem_shmem_create_with_handle(file, dev, args->size, &args->handle);
570}
571EXPORT_SYMBOL_GPL(drm_gem_shmem_dumb_create);
572
573static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf)
574{
575	struct vm_area_struct *vma = vmf->vma;
576	struct drm_gem_object *obj = vma->vm_private_data;
577	struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
578	loff_t num_pages = obj->size >> PAGE_SHIFT;
579	vm_fault_t ret;
580	struct page *page;
581	pgoff_t page_offset;
582
583	/* We don't use vmf->pgoff since that has the fake offset */
584	page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT;
585
586	dma_resv_lock(shmem->base.resv, NULL);
587
588	if (page_offset >= num_pages ||
589	    drm_WARN_ON_ONCE(obj->dev, !shmem->pages) ||
590	    shmem->madv < 0) {
591		ret = VM_FAULT_SIGBUS;
592	} else {
593		page = shmem->pages[page_offset];
594
595		ret = vmf_insert_pfn(vma, vmf->address, page_to_pfn(page));
596	}
597
598	dma_resv_unlock(shmem->base.resv);
599
600	return ret;
601}
602
603static void drm_gem_shmem_vm_open(struct vm_area_struct *vma)
604{
605	struct drm_gem_object *obj = vma->vm_private_data;
606	struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
607
608	drm_WARN_ON(obj->dev, drm_gem_is_imported(obj));
609
610	dma_resv_lock(shmem->base.resv, NULL);
611
612	/*
613	 * We should have already pinned the pages when the buffer was first
614	 * mmap'd, vm_open() just grabs an additional reference for the new
615	 * mm the vma is getting copied into (ie. on fork()).
616	 */
617	drm_WARN_ON_ONCE(obj->dev,
618			 !refcount_inc_not_zero(&shmem->pages_use_count));
619
620	dma_resv_unlock(shmem->base.resv);
621
622	drm_gem_vm_open(vma);
623}
624
625static void drm_gem_shmem_vm_close(struct vm_area_struct *vma)
626{
627	struct drm_gem_object *obj = vma->vm_private_data;
628	struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
629
630	dma_resv_lock(shmem->base.resv, NULL);
631	drm_gem_shmem_put_pages_locked(shmem);
632	dma_resv_unlock(shmem->base.resv);
633
634	drm_gem_vm_close(vma);
635}
636
637const struct vm_operations_struct drm_gem_shmem_vm_ops = {
638	.fault = drm_gem_shmem_fault,
639	.open = drm_gem_shmem_vm_open,
640	.close = drm_gem_shmem_vm_close,
641};
642EXPORT_SYMBOL_GPL(drm_gem_shmem_vm_ops);
643
644/**
645 * drm_gem_shmem_mmap - Memory-map a shmem GEM object
646 * @shmem: shmem GEM object
647 * @vma: VMA for the area to be mapped
648 *
649 * This function implements an augmented version of the GEM DRM file mmap
650 * operation for shmem objects.
651 *
652 * Returns:
653 * 0 on success or a negative error code on failure.
654 */
655int drm_gem_shmem_mmap(struct drm_gem_shmem_object *shmem, struct vm_area_struct *vma)
656{
657	struct drm_gem_object *obj = &shmem->base;
658	int ret;
659
660	if (drm_gem_is_imported(obj)) {
661		/* Reset both vm_ops and vm_private_data, so we don't end up with
662		 * vm_ops pointing to our implementation if the dma-buf backend
663		 * doesn't set those fields.
664		 */
665		vma->vm_private_data = NULL;
666		vma->vm_ops = NULL;
667
668		ret = dma_buf_mmap(obj->dma_buf, vma, 0);
669
670		/* Drop the reference drm_gem_mmap_obj() acquired.*/
671		if (!ret)
672			drm_gem_object_put(obj);
673
674		return ret;
675	}
676
677	if (is_cow_mapping(vma->vm_flags))
678		return -EINVAL;
679
680	dma_resv_lock(shmem->base.resv, NULL);
681	ret = drm_gem_shmem_get_pages_locked(shmem);
682	dma_resv_unlock(shmem->base.resv);
683
684	if (ret)
685		return ret;
686
687	vm_flags_set(vma, VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP);
688	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
689	if (shmem->map_wc)
690		vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
691
692	return 0;
693}
694EXPORT_SYMBOL_GPL(drm_gem_shmem_mmap);
695
696/**
697 * drm_gem_shmem_print_info() - Print &drm_gem_shmem_object info for debugfs
698 * @shmem: shmem GEM object
699 * @p: DRM printer
700 * @indent: Tab indentation level
701 */
702void drm_gem_shmem_print_info(const struct drm_gem_shmem_object *shmem,
703			      struct drm_printer *p, unsigned int indent)
704{
705	if (drm_gem_is_imported(&shmem->base))
706		return;
707
708	drm_printf_indent(p, indent, "pages_pin_count=%u\n", refcount_read(&shmem->pages_pin_count));
709	drm_printf_indent(p, indent, "pages_use_count=%u\n", refcount_read(&shmem->pages_use_count));
710	drm_printf_indent(p, indent, "vmap_use_count=%u\n", refcount_read(&shmem->vmap_use_count));
711	drm_printf_indent(p, indent, "vaddr=%p\n", shmem->vaddr);
712}
713EXPORT_SYMBOL_GPL(drm_gem_shmem_print_info);
714
715/**
716 * drm_gem_shmem_get_sg_table - Provide a scatter/gather table of pinned
717 *                              pages for a shmem GEM object
718 * @shmem: shmem GEM object
719 *
720 * This function exports a scatter/gather table suitable for PRIME usage by
721 * calling the standard DMA mapping API.
722 *
723 * Drivers who need to acquire an scatter/gather table for objects need to call
724 * drm_gem_shmem_get_pages_sgt() instead.
725 *
726 * Returns:
727 * A pointer to the scatter/gather table of pinned pages or error pointer on failure.
728 */
729struct sg_table *drm_gem_shmem_get_sg_table(struct drm_gem_shmem_object *shmem)
730{
731	struct drm_gem_object *obj = &shmem->base;
732
733	drm_WARN_ON(obj->dev, drm_gem_is_imported(obj));
734
735	return drm_prime_pages_to_sg(obj->dev, shmem->pages, obj->size >> PAGE_SHIFT);
736}
737EXPORT_SYMBOL_GPL(drm_gem_shmem_get_sg_table);
738
739static struct sg_table *drm_gem_shmem_get_pages_sgt_locked(struct drm_gem_shmem_object *shmem)
740{
741	struct drm_gem_object *obj = &shmem->base;
742	int ret;
743	struct sg_table *sgt;
744
745	if (shmem->sgt)
746		return shmem->sgt;
747
748	drm_WARN_ON(obj->dev, drm_gem_is_imported(obj));
749
750	ret = drm_gem_shmem_get_pages_locked(shmem);
751	if (ret)
752		return ERR_PTR(ret);
753
754	sgt = drm_gem_shmem_get_sg_table(shmem);
755	if (IS_ERR(sgt)) {
756		ret = PTR_ERR(sgt);
757		goto err_put_pages;
758	}
759	/* Map the pages for use by the h/w. */
760	ret = dma_map_sgtable(obj->dev->dev, sgt, DMA_BIDIRECTIONAL, 0);
761	if (ret)
762		goto err_free_sgt;
763
764	shmem->sgt = sgt;
765
766	return sgt;
767
768err_free_sgt:
769	sg_free_table(sgt);
770	kfree(sgt);
771err_put_pages:
772	drm_gem_shmem_put_pages_locked(shmem);
773	return ERR_PTR(ret);
774}
775
776/**
777 * drm_gem_shmem_get_pages_sgt - Pin pages, dma map them, and return a
778 *				 scatter/gather table for a shmem GEM object.
779 * @shmem: shmem GEM object
780 *
781 * This function returns a scatter/gather table suitable for driver usage. If
782 * the sg table doesn't exist, the pages are pinned, dma-mapped, and a sg
783 * table created.
784 *
785 * This is the main function for drivers to get at backing storage, and it hides
786 * and difference between dma-buf imported and natively allocated objects.
787 * drm_gem_shmem_get_sg_table() should not be directly called by drivers.
788 *
789 * Returns:
790 * A pointer to the scatter/gather table of pinned pages or errno on failure.
791 */
792struct sg_table *drm_gem_shmem_get_pages_sgt(struct drm_gem_shmem_object *shmem)
793{
794	int ret;
795	struct sg_table *sgt;
796
797	ret = dma_resv_lock_interruptible(shmem->base.resv, NULL);
798	if (ret)
799		return ERR_PTR(ret);
800	sgt = drm_gem_shmem_get_pages_sgt_locked(shmem);
801	dma_resv_unlock(shmem->base.resv);
802
803	return sgt;
804}
805EXPORT_SYMBOL_GPL(drm_gem_shmem_get_pages_sgt);
806
807/**
808 * drm_gem_shmem_prime_import_sg_table - Produce a shmem GEM object from
809 *                 another driver's scatter/gather table of pinned pages
810 * @dev: Device to import into
811 * @attach: DMA-BUF attachment
812 * @sgt: Scatter/gather table of pinned pages
813 *
814 * This function imports a scatter/gather table exported via DMA-BUF by
815 * another driver. Drivers that use the shmem helpers should set this as their
816 * &drm_driver.gem_prime_import_sg_table callback.
817 *
818 * Returns:
819 * A pointer to a newly created GEM object or an ERR_PTR-encoded negative
820 * error code on failure.
821 */
822struct drm_gem_object *
823drm_gem_shmem_prime_import_sg_table(struct drm_device *dev,
824				    struct dma_buf_attachment *attach,
825				    struct sg_table *sgt)
826{
827	size_t size = PAGE_ALIGN(attach->dmabuf->size);
828	struct drm_gem_shmem_object *shmem;
829
830	shmem = __drm_gem_shmem_create(dev, size, true, NULL);
831	if (IS_ERR(shmem))
832		return ERR_CAST(shmem);
833
834	shmem->sgt = sgt;
835
836	drm_dbg_prime(dev, "size = %zu\n", size);
837
838	return &shmem->base;
839}
840EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import_sg_table);
841
842/**
843 * drm_gem_shmem_prime_import_no_map - Import dmabuf without mapping its sg_table
844 * @dev: Device to import into
845 * @dma_buf: dma-buf object to import
846 *
847 * Drivers that use the shmem helpers but also wants to import dmabuf without
848 * mapping its sg_table can use this as their &drm_driver.gem_prime_import
849 * implementation.
850 */
851struct drm_gem_object *drm_gem_shmem_prime_import_no_map(struct drm_device *dev,
852							 struct dma_buf *dma_buf)
853{
854	struct dma_buf_attachment *attach;
855	struct drm_gem_shmem_object *shmem;
856	struct drm_gem_object *obj;
857	size_t size;
858	int ret;
859
860	if (drm_gem_is_prime_exported_dma_buf(dev, dma_buf)) {
861		/*
862		 * Importing dmabuf exported from our own gem increases
863		 * refcount on gem itself instead of f_count of dmabuf.
864		 */
865		obj = dma_buf->priv;
866		drm_gem_object_get(obj);
867		return obj;
868	}
869
870	attach = dma_buf_attach(dma_buf, dev->dev);
871	if (IS_ERR(attach))
872		return ERR_CAST(attach);
873
874	get_dma_buf(dma_buf);
875
876	size = PAGE_ALIGN(attach->dmabuf->size);
877
878	shmem = __drm_gem_shmem_create(dev, size, true, NULL);
879	if (IS_ERR(shmem)) {
880		ret = PTR_ERR(shmem);
881		goto fail_detach;
882	}
883
884	drm_dbg_prime(dev, "size = %zu\n", size);
885
886	shmem->base.import_attach = attach;
887	shmem->base.resv = dma_buf->resv;
888
889	return &shmem->base;
890
891fail_detach:
892	dma_buf_detach(dma_buf, attach);
893	dma_buf_put(dma_buf);
894
895	return ERR_PTR(ret);
896}
897EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import_no_map);
898
899/*
900 * Kunit helpers
901 */
902
903#if IS_ENABLED(CONFIG_KUNIT)
904int drm_gem_shmem_vmap(struct drm_gem_shmem_object *shmem, struct iosys_map *map)
905{
906	struct drm_gem_object *obj = &shmem->base;
907	int ret;
908
909	ret = dma_resv_lock_interruptible(obj->resv, NULL);
910	if (ret)
911		return ret;
912	ret = drm_gem_shmem_vmap_locked(shmem, map);
913	dma_resv_unlock(obj->resv);
914
915	return ret;
916}
917EXPORT_SYMBOL_IF_KUNIT(drm_gem_shmem_vmap);
918
919void drm_gem_shmem_vunmap(struct drm_gem_shmem_object *shmem, struct iosys_map *map)
920{
921	struct drm_gem_object *obj = &shmem->base;
922
923	dma_resv_lock_interruptible(obj->resv, NULL);
924	drm_gem_shmem_vunmap_locked(shmem, map);
925	dma_resv_unlock(obj->resv);
926}
927EXPORT_SYMBOL_IF_KUNIT(drm_gem_shmem_vunmap);
928
929int drm_gem_shmem_madvise(struct drm_gem_shmem_object *shmem, int madv)
930{
931	struct drm_gem_object *obj = &shmem->base;
932	int ret;
933
934	ret = dma_resv_lock_interruptible(obj->resv, NULL);
935	if (ret)
936		return ret;
937	ret = drm_gem_shmem_madvise_locked(shmem, madv);
938	dma_resv_unlock(obj->resv);
939
940	return ret;
941}
942EXPORT_SYMBOL_IF_KUNIT(drm_gem_shmem_madvise);
943
944int drm_gem_shmem_purge(struct drm_gem_shmem_object *shmem)
945{
946	struct drm_gem_object *obj = &shmem->base;
947	int ret;
948
949	ret = dma_resv_lock_interruptible(obj->resv, NULL);
950	if (ret)
951		return ret;
952	drm_gem_shmem_purge_locked(shmem);
953	dma_resv_unlock(obj->resv);
954
955	return 0;
956}
957EXPORT_SYMBOL_IF_KUNIT(drm_gem_shmem_purge);
958#endif
959
960MODULE_DESCRIPTION("DRM SHMEM memory-management helpers");
961MODULE_IMPORT_NS("DMA_BUF");
962MODULE_LICENSE("GPL");