1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright 2018 Noralf Trønnes
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 #include <linux/module.h>
16 #include <asm/set_memory.h>
20 #include <drm/drm_device.h>
21 #include <drm/drm_drv.h>
22 #include <drm/drm_gem_shmem_helper.h>
23 #include <drm/drm_prime.h>
24 #include <drm/drm_print.h>
26 MODULE_IMPORT_NS(DMA_BUF);
31 * This library provides helpers for GEM objects backed by shmem buffers
32 * allocated using anonymous pageable memory.
34 * Functions that operate on the GEM object receive struct &drm_gem_shmem_object.
35 * For GEM callback helpers in struct &drm_gem_object functions, see likewise
36 * named functions with an _object_ infix (e.g., drm_gem_shmem_object_vmap() wraps
37 * drm_gem_shmem_vmap()). These helpers perform the necessary type conversion.
40 static const struct drm_gem_object_funcs drm_gem_shmem_funcs = {
41 .free = drm_gem_shmem_object_free,
42 .print_info = drm_gem_shmem_object_print_info,
43 .pin = drm_gem_shmem_object_pin,
44 .unpin = drm_gem_shmem_object_unpin,
45 .get_sg_table = drm_gem_shmem_object_get_sg_table,
46 .vmap = drm_gem_shmem_object_vmap,
47 .vunmap = drm_gem_shmem_object_vunmap,
48 .mmap = drm_gem_shmem_object_mmap,
49 .vm_ops = &drm_gem_shmem_vm_ops,
52 static struct drm_gem_shmem_object *
53 __drm_gem_shmem_create(struct drm_device *dev, size_t size, bool private)
55 struct drm_gem_shmem_object *shmem;
56 struct drm_gem_object *obj;
59 size = PAGE_ALIGN(size);
61 if (dev->driver->gem_create_object) {
62 obj = dev->driver->gem_create_object(dev, size);
65 shmem = to_drm_gem_shmem_obj(obj);
67 shmem = kzalloc(sizeof(*shmem), GFP_KERNEL);
69 return ERR_PTR(-ENOMEM);
74 obj->funcs = &drm_gem_shmem_funcs;
77 drm_gem_private_object_init(dev, obj, size);
78 shmem->map_wc = false; /* dma-buf mappings use always writecombine */
80 ret = drm_gem_object_init(dev, obj, size);
83 drm_gem_private_object_fini(obj);
87 ret = drm_gem_create_mmap_offset(obj);
91 mutex_init(&shmem->pages_lock);
92 mutex_init(&shmem->vmap_lock);
93 INIT_LIST_HEAD(&shmem->madv_list);
97 * Our buffers are kept pinned, so allocating them
98 * from the MOVABLE zone is a really bad idea, and
99 * conflicts with CMA. See comments above new_inode()
100 * why this is required _and_ expected if you're
101 * going to pin these pages.
103 mapping_set_gfp_mask(obj->filp->f_mapping, GFP_HIGHUSER |
104 __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
110 drm_gem_object_release(obj);
117 * drm_gem_shmem_create - Allocate an object with the given size
119 * @size: Size of the object to allocate
121 * This function creates a shmem GEM object.
124 * A struct drm_gem_shmem_object * on success or an ERR_PTR()-encoded negative
125 * error code on failure.
127 struct drm_gem_shmem_object *drm_gem_shmem_create(struct drm_device *dev, size_t size)
129 return __drm_gem_shmem_create(dev, size, false);
131 EXPORT_SYMBOL_GPL(drm_gem_shmem_create);
134 * drm_gem_shmem_free - Free resources associated with a shmem GEM object
135 * @shmem: shmem GEM object to free
137 * This function cleans up the GEM object state and frees the memory used to
138 * store the object itself.
140 void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem)
142 struct drm_gem_object *obj = &shmem->base;
144 WARN_ON(shmem->vmap_use_count);
146 if (obj->import_attach) {
147 drm_prime_gem_destroy(obj, shmem->sgt);
150 dma_unmap_sgtable(obj->dev->dev, shmem->sgt,
151 DMA_BIDIRECTIONAL, 0);
152 sg_free_table(shmem->sgt);
156 drm_gem_shmem_put_pages(shmem);
159 WARN_ON(shmem->pages_use_count);
161 drm_gem_object_release(obj);
162 mutex_destroy(&shmem->pages_lock);
163 mutex_destroy(&shmem->vmap_lock);
166 EXPORT_SYMBOL_GPL(drm_gem_shmem_free);
168 static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem)
170 struct drm_gem_object *obj = &shmem->base;
173 if (shmem->pages_use_count++ > 0)
176 pages = drm_gem_get_pages(obj);
178 DRM_DEBUG_KMS("Failed to get pages (%ld)\n", PTR_ERR(pages));
179 shmem->pages_use_count = 0;
180 return PTR_ERR(pages);
184 * TODO: Allocating WC pages which are correctly flushed is only
185 * supported on x86. Ideal solution would be a GFP_WC flag, which also
186 * ttm_pool.c could use.
190 set_pages_array_wc(pages, obj->size >> PAGE_SHIFT);
193 shmem->pages = pages;
199 * drm_gem_shmem_get_pages - Allocate backing pages for a shmem GEM object
200 * @shmem: shmem GEM object
202 * This function makes sure that backing pages exists for the shmem GEM object
203 * and increases the use count.
206 * 0 on success or a negative error code on failure.
208 int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem)
212 WARN_ON(shmem->base.import_attach);
214 ret = mutex_lock_interruptible(&shmem->pages_lock);
217 ret = drm_gem_shmem_get_pages_locked(shmem);
218 mutex_unlock(&shmem->pages_lock);
222 EXPORT_SYMBOL(drm_gem_shmem_get_pages);
224 static void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem)
226 struct drm_gem_object *obj = &shmem->base;
228 if (WARN_ON_ONCE(!shmem->pages_use_count))
231 if (--shmem->pages_use_count > 0)
236 set_pages_array_wb(shmem->pages, obj->size >> PAGE_SHIFT);
239 drm_gem_put_pages(obj, shmem->pages,
240 shmem->pages_mark_dirty_on_put,
241 shmem->pages_mark_accessed_on_put);
246 * drm_gem_shmem_put_pages - Decrease use count on the backing pages for a shmem GEM object
247 * @shmem: shmem GEM object
249 * This function decreases the use count and puts the backing pages when use drops to zero.
251 void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem)
253 mutex_lock(&shmem->pages_lock);
254 drm_gem_shmem_put_pages_locked(shmem);
255 mutex_unlock(&shmem->pages_lock);
257 EXPORT_SYMBOL(drm_gem_shmem_put_pages);
260 * drm_gem_shmem_pin - Pin backing pages for a shmem GEM object
261 * @shmem: shmem GEM object
263 * This function makes sure the backing pages are pinned in memory while the
264 * buffer is exported.
267 * 0 on success or a negative error code on failure.
269 int drm_gem_shmem_pin(struct drm_gem_shmem_object *shmem)
271 WARN_ON(shmem->base.import_attach);
273 return drm_gem_shmem_get_pages(shmem);
275 EXPORT_SYMBOL(drm_gem_shmem_pin);
278 * drm_gem_shmem_unpin - Unpin backing pages for a shmem GEM object
279 * @shmem: shmem GEM object
281 * This function removes the requirement that the backing pages are pinned in
284 void drm_gem_shmem_unpin(struct drm_gem_shmem_object *shmem)
286 WARN_ON(shmem->base.import_attach);
288 drm_gem_shmem_put_pages(shmem);
290 EXPORT_SYMBOL(drm_gem_shmem_unpin);
292 static int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem,
293 struct iosys_map *map)
295 struct drm_gem_object *obj = &shmem->base;
298 if (shmem->vmap_use_count++ > 0) {
299 iosys_map_set_vaddr(map, shmem->vaddr);
303 if (obj->import_attach) {
304 ret = dma_buf_vmap(obj->import_attach->dmabuf, map);
306 if (WARN_ON(map->is_iomem)) {
307 dma_buf_vunmap(obj->import_attach->dmabuf, map);
311 shmem->vaddr = map->vaddr;
314 pgprot_t prot = PAGE_KERNEL;
316 ret = drm_gem_shmem_get_pages(shmem);
321 prot = pgprot_writecombine(prot);
322 shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT,
327 iosys_map_set_vaddr(map, shmem->vaddr);
331 DRM_DEBUG_KMS("Failed to vmap pages, error %d\n", ret);
338 if (!obj->import_attach)
339 drm_gem_shmem_put_pages(shmem);
341 shmem->vmap_use_count = 0;
347 * drm_gem_shmem_vmap - Create a virtual mapping for a shmem GEM object
348 * @shmem: shmem GEM object
349 * @map: Returns the kernel virtual address of the SHMEM GEM object's backing
352 * This function makes sure that a contiguous kernel virtual address mapping
353 * exists for the buffer backing the shmem GEM object. It hides the differences
354 * between dma-buf imported and natively allocated objects.
356 * Acquired mappings should be cleaned up by calling drm_gem_shmem_vunmap().
359 * 0 on success or a negative error code on failure.
361 int drm_gem_shmem_vmap(struct drm_gem_shmem_object *shmem,
362 struct iosys_map *map)
366 ret = mutex_lock_interruptible(&shmem->vmap_lock);
369 ret = drm_gem_shmem_vmap_locked(shmem, map);
370 mutex_unlock(&shmem->vmap_lock);
374 EXPORT_SYMBOL(drm_gem_shmem_vmap);
376 static void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem,
377 struct iosys_map *map)
379 struct drm_gem_object *obj = &shmem->base;
381 if (WARN_ON_ONCE(!shmem->vmap_use_count))
384 if (--shmem->vmap_use_count > 0)
387 if (obj->import_attach) {
388 dma_buf_vunmap(obj->import_attach->dmabuf, map);
390 vunmap(shmem->vaddr);
391 drm_gem_shmem_put_pages(shmem);
398 * drm_gem_shmem_vunmap - Unmap a virtual mapping for a shmem GEM object
399 * @shmem: shmem GEM object
400 * @map: Kernel virtual address where the SHMEM GEM object was mapped
402 * This function cleans up a kernel virtual address mapping acquired by
403 * drm_gem_shmem_vmap(). The mapping is only removed when the use count drops to
406 * This function hides the differences between dma-buf imported and natively
409 void drm_gem_shmem_vunmap(struct drm_gem_shmem_object *shmem,
410 struct iosys_map *map)
412 mutex_lock(&shmem->vmap_lock);
413 drm_gem_shmem_vunmap_locked(shmem, map);
414 mutex_unlock(&shmem->vmap_lock);
416 EXPORT_SYMBOL(drm_gem_shmem_vunmap);
418 static struct drm_gem_shmem_object *
419 drm_gem_shmem_create_with_handle(struct drm_file *file_priv,
420 struct drm_device *dev, size_t size,
423 struct drm_gem_shmem_object *shmem;
426 shmem = drm_gem_shmem_create(dev, size);
431 * Allocate an id of idr table where the obj is registered
432 * and handle has the id what user can see.
434 ret = drm_gem_handle_create(file_priv, &shmem->base, handle);
435 /* drop reference from allocate - handle holds it now. */
436 drm_gem_object_put(&shmem->base);
443 /* Update madvise status, returns true if not purged, else
446 int drm_gem_shmem_madvise(struct drm_gem_shmem_object *shmem, int madv)
448 mutex_lock(&shmem->pages_lock);
450 if (shmem->madv >= 0)
455 mutex_unlock(&shmem->pages_lock);
459 EXPORT_SYMBOL(drm_gem_shmem_madvise);
461 void drm_gem_shmem_purge_locked(struct drm_gem_shmem_object *shmem)
463 struct drm_gem_object *obj = &shmem->base;
464 struct drm_device *dev = obj->dev;
466 WARN_ON(!drm_gem_shmem_is_purgeable(shmem));
468 dma_unmap_sgtable(dev->dev, shmem->sgt, DMA_BIDIRECTIONAL, 0);
469 sg_free_table(shmem->sgt);
473 drm_gem_shmem_put_pages_locked(shmem);
477 drm_vma_node_unmap(&obj->vma_node, dev->anon_inode->i_mapping);
478 drm_gem_free_mmap_offset(obj);
480 /* Our goal here is to return as much of the memory as
481 * is possible back to the system as we are called from OOM.
482 * To do this we must instruct the shmfs to drop all of its
483 * backing pages, *now*.
485 shmem_truncate_range(file_inode(obj->filp), 0, (loff_t)-1);
487 invalidate_mapping_pages(file_inode(obj->filp)->i_mapping, 0, (loff_t)-1);
489 EXPORT_SYMBOL(drm_gem_shmem_purge_locked);
491 bool drm_gem_shmem_purge(struct drm_gem_shmem_object *shmem)
493 if (!mutex_trylock(&shmem->pages_lock))
495 drm_gem_shmem_purge_locked(shmem);
496 mutex_unlock(&shmem->pages_lock);
500 EXPORT_SYMBOL(drm_gem_shmem_purge);
503 * drm_gem_shmem_dumb_create - Create a dumb shmem buffer object
504 * @file: DRM file structure to create the dumb buffer for
508 * This function computes the pitch of the dumb buffer and rounds it up to an
509 * integer number of bytes per pixel. Drivers for hardware that doesn't have
510 * any additional restrictions on the pitch can directly use this function as
511 * their &drm_driver.dumb_create callback.
513 * For hardware with additional restrictions, drivers can adjust the fields
514 * set up by userspace before calling into this function.
517 * 0 on success or a negative error code on failure.
519 int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device *dev,
520 struct drm_mode_create_dumb *args)
522 u32 min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
523 struct drm_gem_shmem_object *shmem;
525 if (!args->pitch || !args->size) {
526 args->pitch = min_pitch;
527 args->size = PAGE_ALIGN(args->pitch * args->height);
529 /* ensure sane minimum values */
530 if (args->pitch < min_pitch)
531 args->pitch = min_pitch;
532 if (args->size < args->pitch * args->height)
533 args->size = PAGE_ALIGN(args->pitch * args->height);
536 shmem = drm_gem_shmem_create_with_handle(file, dev, args->size, &args->handle);
538 return PTR_ERR_OR_ZERO(shmem);
540 EXPORT_SYMBOL_GPL(drm_gem_shmem_dumb_create);
542 static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf)
544 struct vm_area_struct *vma = vmf->vma;
545 struct drm_gem_object *obj = vma->vm_private_data;
546 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
547 loff_t num_pages = obj->size >> PAGE_SHIFT;
552 /* We don't use vmf->pgoff since that has the fake offset */
553 page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT;
555 mutex_lock(&shmem->pages_lock);
557 if (page_offset >= num_pages ||
558 WARN_ON_ONCE(!shmem->pages) ||
560 ret = VM_FAULT_SIGBUS;
562 page = shmem->pages[page_offset];
564 ret = vmf_insert_pfn(vma, vmf->address, page_to_pfn(page));
567 mutex_unlock(&shmem->pages_lock);
572 static void drm_gem_shmem_vm_open(struct vm_area_struct *vma)
574 struct drm_gem_object *obj = vma->vm_private_data;
575 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
577 WARN_ON(shmem->base.import_attach);
579 mutex_lock(&shmem->pages_lock);
582 * We should have already pinned the pages when the buffer was first
583 * mmap'd, vm_open() just grabs an additional reference for the new
584 * mm the vma is getting copied into (ie. on fork()).
586 if (!WARN_ON_ONCE(!shmem->pages_use_count))
587 shmem->pages_use_count++;
589 mutex_unlock(&shmem->pages_lock);
591 drm_gem_vm_open(vma);
594 static void drm_gem_shmem_vm_close(struct vm_area_struct *vma)
596 struct drm_gem_object *obj = vma->vm_private_data;
597 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
599 drm_gem_shmem_put_pages(shmem);
600 drm_gem_vm_close(vma);
603 const struct vm_operations_struct drm_gem_shmem_vm_ops = {
604 .fault = drm_gem_shmem_fault,
605 .open = drm_gem_shmem_vm_open,
606 .close = drm_gem_shmem_vm_close,
608 EXPORT_SYMBOL_GPL(drm_gem_shmem_vm_ops);
611 * drm_gem_shmem_mmap - Memory-map a shmem GEM object
612 * @shmem: shmem GEM object
613 * @vma: VMA for the area to be mapped
615 * This function implements an augmented version of the GEM DRM file mmap
616 * operation for shmem objects.
619 * 0 on success or a negative error code on failure.
621 int drm_gem_shmem_mmap(struct drm_gem_shmem_object *shmem, struct vm_area_struct *vma)
623 struct drm_gem_object *obj = &shmem->base;
626 if (obj->import_attach) {
627 /* Drop the reference drm_gem_mmap_obj() acquired.*/
628 drm_gem_object_put(obj);
629 vma->vm_private_data = NULL;
631 return dma_buf_mmap(obj->dma_buf, vma, 0);
634 ret = drm_gem_shmem_get_pages(shmem);
638 vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
639 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
641 vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
645 EXPORT_SYMBOL_GPL(drm_gem_shmem_mmap);
648 * drm_gem_shmem_print_info() - Print &drm_gem_shmem_object info for debugfs
649 * @shmem: shmem GEM object
651 * @indent: Tab indentation level
653 void drm_gem_shmem_print_info(const struct drm_gem_shmem_object *shmem,
654 struct drm_printer *p, unsigned int indent)
656 drm_printf_indent(p, indent, "pages_use_count=%u\n", shmem->pages_use_count);
657 drm_printf_indent(p, indent, "vmap_use_count=%u\n", shmem->vmap_use_count);
658 drm_printf_indent(p, indent, "vaddr=%p\n", shmem->vaddr);
660 EXPORT_SYMBOL(drm_gem_shmem_print_info);
663 * drm_gem_shmem_get_sg_table - Provide a scatter/gather table of pinned
664 * pages for a shmem GEM object
665 * @shmem: shmem GEM object
667 * This function exports a scatter/gather table suitable for PRIME usage by
668 * calling the standard DMA mapping API.
670 * Drivers who need to acquire an scatter/gather table for objects need to call
671 * drm_gem_shmem_get_pages_sgt() instead.
674 * A pointer to the scatter/gather table of pinned pages or error pointer on failure.
676 struct sg_table *drm_gem_shmem_get_sg_table(struct drm_gem_shmem_object *shmem)
678 struct drm_gem_object *obj = &shmem->base;
680 WARN_ON(shmem->base.import_attach);
682 return drm_prime_pages_to_sg(obj->dev, shmem->pages, obj->size >> PAGE_SHIFT);
684 EXPORT_SYMBOL_GPL(drm_gem_shmem_get_sg_table);
687 * drm_gem_shmem_get_pages_sgt - Pin pages, dma map them, and return a
688 * scatter/gather table for a shmem GEM object.
689 * @shmem: shmem GEM object
691 * This function returns a scatter/gather table suitable for driver usage. If
692 * the sg table doesn't exist, the pages are pinned, dma-mapped, and a sg
695 * This is the main function for drivers to get at backing storage, and it hides
696 * and difference between dma-buf imported and natively allocated objects.
697 * drm_gem_shmem_get_sg_table() should not be directly called by drivers.
700 * A pointer to the scatter/gather table of pinned pages or errno on failure.
702 struct sg_table *drm_gem_shmem_get_pages_sgt(struct drm_gem_shmem_object *shmem)
704 struct drm_gem_object *obj = &shmem->base;
706 struct sg_table *sgt;
711 WARN_ON(obj->import_attach);
713 ret = drm_gem_shmem_get_pages(shmem);
717 sgt = drm_gem_shmem_get_sg_table(shmem);
722 /* Map the pages for use by the h/w. */
723 ret = dma_map_sgtable(obj->dev->dev, sgt, DMA_BIDIRECTIONAL, 0);
735 drm_gem_shmem_put_pages(shmem);
738 EXPORT_SYMBOL_GPL(drm_gem_shmem_get_pages_sgt);
741 * drm_gem_shmem_prime_import_sg_table - Produce a shmem GEM object from
742 * another driver's scatter/gather table of pinned pages
743 * @dev: Device to import into
744 * @attach: DMA-BUF attachment
745 * @sgt: Scatter/gather table of pinned pages
747 * This function imports a scatter/gather table exported via DMA-BUF by
748 * another driver. Drivers that use the shmem helpers should set this as their
749 * &drm_driver.gem_prime_import_sg_table callback.
752 * A pointer to a newly created GEM object or an ERR_PTR-encoded negative
753 * error code on failure.
755 struct drm_gem_object *
756 drm_gem_shmem_prime_import_sg_table(struct drm_device *dev,
757 struct dma_buf_attachment *attach,
758 struct sg_table *sgt)
760 size_t size = PAGE_ALIGN(attach->dmabuf->size);
761 struct drm_gem_shmem_object *shmem;
763 shmem = __drm_gem_shmem_create(dev, size, true);
765 return ERR_CAST(shmem);
769 DRM_DEBUG_PRIME("size = %zu\n", size);
773 EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import_sg_table);
775 MODULE_DESCRIPTION("DRM SHMEM memory-management helpers");
776 MODULE_IMPORT_NS(DMA_BUF);
777 MODULE_LICENSE("GPL v2");