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);
85 ret = drm_gem_create_mmap_offset(obj);
89 mutex_init(&shmem->pages_lock);
90 mutex_init(&shmem->vmap_lock);
91 INIT_LIST_HEAD(&shmem->madv_list);
95 * Our buffers are kept pinned, so allocating them
96 * from the MOVABLE zone is a really bad idea, and
97 * conflicts with CMA. See comments above new_inode()
98 * why this is required _and_ expected if you're
99 * going to pin these pages.
101 mapping_set_gfp_mask(obj->filp->f_mapping, GFP_HIGHUSER |
102 __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
108 drm_gem_object_release(obj);
115 * drm_gem_shmem_create - Allocate an object with the given size
117 * @size: Size of the object to allocate
119 * This function creates a shmem GEM object.
122 * A struct drm_gem_shmem_object * on success or an ERR_PTR()-encoded negative
123 * error code on failure.
125 struct drm_gem_shmem_object *drm_gem_shmem_create(struct drm_device *dev, size_t size)
127 return __drm_gem_shmem_create(dev, size, false);
129 EXPORT_SYMBOL_GPL(drm_gem_shmem_create);
132 * drm_gem_shmem_free - Free resources associated with a shmem GEM object
133 * @shmem: shmem GEM object to free
135 * This function cleans up the GEM object state and frees the memory used to
136 * store the object itself.
138 void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem)
140 struct drm_gem_object *obj = &shmem->base;
142 WARN_ON(shmem->vmap_use_count);
144 if (obj->import_attach) {
145 drm_prime_gem_destroy(obj, shmem->sgt);
148 dma_unmap_sgtable(obj->dev->dev, shmem->sgt,
149 DMA_BIDIRECTIONAL, 0);
150 sg_free_table(shmem->sgt);
154 drm_gem_shmem_put_pages(shmem);
157 WARN_ON(shmem->pages_use_count);
159 drm_gem_object_release(obj);
160 mutex_destroy(&shmem->pages_lock);
161 mutex_destroy(&shmem->vmap_lock);
164 EXPORT_SYMBOL_GPL(drm_gem_shmem_free);
166 static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem)
168 struct drm_gem_object *obj = &shmem->base;
171 if (shmem->pages_use_count++ > 0)
174 pages = drm_gem_get_pages(obj);
176 DRM_DEBUG_KMS("Failed to get pages (%ld)\n", PTR_ERR(pages));
177 shmem->pages_use_count = 0;
178 return PTR_ERR(pages);
182 * TODO: Allocating WC pages which are correctly flushed is only
183 * supported on x86. Ideal solution would be a GFP_WC flag, which also
184 * ttm_pool.c could use.
188 set_pages_array_wc(pages, obj->size >> PAGE_SHIFT);
191 shmem->pages = pages;
197 * drm_gem_shmem_get_pages - Allocate backing pages for a shmem GEM object
198 * @shmem: shmem GEM object
200 * This function makes sure that backing pages exists for the shmem GEM object
201 * and increases the use count.
204 * 0 on success or a negative error code on failure.
206 int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem)
210 WARN_ON(shmem->base.import_attach);
212 ret = mutex_lock_interruptible(&shmem->pages_lock);
215 ret = drm_gem_shmem_get_pages_locked(shmem);
216 mutex_unlock(&shmem->pages_lock);
220 EXPORT_SYMBOL(drm_gem_shmem_get_pages);
222 static void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem)
224 struct drm_gem_object *obj = &shmem->base;
226 if (WARN_ON_ONCE(!shmem->pages_use_count))
229 if (--shmem->pages_use_count > 0)
234 set_pages_array_wb(shmem->pages, obj->size >> PAGE_SHIFT);
237 drm_gem_put_pages(obj, shmem->pages,
238 shmem->pages_mark_dirty_on_put,
239 shmem->pages_mark_accessed_on_put);
244 * drm_gem_shmem_put_pages - Decrease use count on the backing pages for a shmem GEM object
245 * @shmem: shmem GEM object
247 * This function decreases the use count and puts the backing pages when use drops to zero.
249 void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem)
251 mutex_lock(&shmem->pages_lock);
252 drm_gem_shmem_put_pages_locked(shmem);
253 mutex_unlock(&shmem->pages_lock);
255 EXPORT_SYMBOL(drm_gem_shmem_put_pages);
258 * drm_gem_shmem_pin - Pin backing pages for a shmem GEM object
259 * @shmem: shmem GEM object
261 * This function makes sure the backing pages are pinned in memory while the
262 * buffer is exported.
265 * 0 on success or a negative error code on failure.
267 int drm_gem_shmem_pin(struct drm_gem_shmem_object *shmem)
269 WARN_ON(shmem->base.import_attach);
271 return drm_gem_shmem_get_pages(shmem);
273 EXPORT_SYMBOL(drm_gem_shmem_pin);
276 * drm_gem_shmem_unpin - Unpin backing pages for a shmem GEM object
277 * @shmem: shmem GEM object
279 * This function removes the requirement that the backing pages are pinned in
282 void drm_gem_shmem_unpin(struct drm_gem_shmem_object *shmem)
284 WARN_ON(shmem->base.import_attach);
286 drm_gem_shmem_put_pages(shmem);
288 EXPORT_SYMBOL(drm_gem_shmem_unpin);
290 static int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem,
291 struct iosys_map *map)
293 struct drm_gem_object *obj = &shmem->base;
296 if (shmem->vmap_use_count++ > 0) {
297 iosys_map_set_vaddr(map, shmem->vaddr);
301 if (obj->import_attach) {
302 ret = dma_buf_vmap(obj->import_attach->dmabuf, map);
304 if (WARN_ON(map->is_iomem)) {
305 dma_buf_vunmap(obj->import_attach->dmabuf, map);
309 shmem->vaddr = map->vaddr;
312 pgprot_t prot = PAGE_KERNEL;
314 ret = drm_gem_shmem_get_pages(shmem);
319 prot = pgprot_writecombine(prot);
320 shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT,
325 iosys_map_set_vaddr(map, shmem->vaddr);
329 DRM_DEBUG_KMS("Failed to vmap pages, error %d\n", ret);
336 if (!obj->import_attach)
337 drm_gem_shmem_put_pages(shmem);
339 shmem->vmap_use_count = 0;
345 * drm_gem_shmem_vmap - Create a virtual mapping for a shmem GEM object
346 * @shmem: shmem GEM object
347 * @map: Returns the kernel virtual address of the SHMEM GEM object's backing
350 * This function makes sure that a contiguous kernel virtual address mapping
351 * exists for the buffer backing the shmem GEM object. It hides the differences
352 * between dma-buf imported and natively allocated objects.
354 * Acquired mappings should be cleaned up by calling drm_gem_shmem_vunmap().
357 * 0 on success or a negative error code on failure.
359 int drm_gem_shmem_vmap(struct drm_gem_shmem_object *shmem,
360 struct iosys_map *map)
364 ret = mutex_lock_interruptible(&shmem->vmap_lock);
367 ret = drm_gem_shmem_vmap_locked(shmem, map);
368 mutex_unlock(&shmem->vmap_lock);
372 EXPORT_SYMBOL(drm_gem_shmem_vmap);
374 static void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem,
375 struct iosys_map *map)
377 struct drm_gem_object *obj = &shmem->base;
379 if (WARN_ON_ONCE(!shmem->vmap_use_count))
382 if (--shmem->vmap_use_count > 0)
385 if (obj->import_attach) {
386 dma_buf_vunmap(obj->import_attach->dmabuf, map);
388 vunmap(shmem->vaddr);
389 drm_gem_shmem_put_pages(shmem);
396 * drm_gem_shmem_vunmap - Unmap a virtual mapping for a shmem GEM object
397 * @shmem: shmem GEM object
398 * @map: Kernel virtual address where the SHMEM GEM object was mapped
400 * This function cleans up a kernel virtual address mapping acquired by
401 * drm_gem_shmem_vmap(). The mapping is only removed when the use count drops to
404 * This function hides the differences between dma-buf imported and natively
407 void drm_gem_shmem_vunmap(struct drm_gem_shmem_object *shmem,
408 struct iosys_map *map)
410 mutex_lock(&shmem->vmap_lock);
411 drm_gem_shmem_vunmap_locked(shmem, map);
412 mutex_unlock(&shmem->vmap_lock);
414 EXPORT_SYMBOL(drm_gem_shmem_vunmap);
416 static struct drm_gem_shmem_object *
417 drm_gem_shmem_create_with_handle(struct drm_file *file_priv,
418 struct drm_device *dev, size_t size,
421 struct drm_gem_shmem_object *shmem;
424 shmem = drm_gem_shmem_create(dev, size);
429 * Allocate an id of idr table where the obj is registered
430 * and handle has the id what user can see.
432 ret = drm_gem_handle_create(file_priv, &shmem->base, handle);
433 /* drop reference from allocate - handle holds it now. */
434 drm_gem_object_put(&shmem->base);
441 /* Update madvise status, returns true if not purged, else
444 int drm_gem_shmem_madvise(struct drm_gem_shmem_object *shmem, int madv)
446 mutex_lock(&shmem->pages_lock);
448 if (shmem->madv >= 0)
453 mutex_unlock(&shmem->pages_lock);
457 EXPORT_SYMBOL(drm_gem_shmem_madvise);
459 void drm_gem_shmem_purge_locked(struct drm_gem_shmem_object *shmem)
461 struct drm_gem_object *obj = &shmem->base;
462 struct drm_device *dev = obj->dev;
464 WARN_ON(!drm_gem_shmem_is_purgeable(shmem));
466 dma_unmap_sgtable(dev->dev, shmem->sgt, DMA_BIDIRECTIONAL, 0);
467 sg_free_table(shmem->sgt);
471 drm_gem_shmem_put_pages_locked(shmem);
475 drm_vma_node_unmap(&obj->vma_node, dev->anon_inode->i_mapping);
476 drm_gem_free_mmap_offset(obj);
478 /* Our goal here is to return as much of the memory as
479 * is possible back to the system as we are called from OOM.
480 * To do this we must instruct the shmfs to drop all of its
481 * backing pages, *now*.
483 shmem_truncate_range(file_inode(obj->filp), 0, (loff_t)-1);
485 invalidate_mapping_pages(file_inode(obj->filp)->i_mapping, 0, (loff_t)-1);
487 EXPORT_SYMBOL(drm_gem_shmem_purge_locked);
489 bool drm_gem_shmem_purge(struct drm_gem_shmem_object *shmem)
491 if (!mutex_trylock(&shmem->pages_lock))
493 drm_gem_shmem_purge_locked(shmem);
494 mutex_unlock(&shmem->pages_lock);
498 EXPORT_SYMBOL(drm_gem_shmem_purge);
501 * drm_gem_shmem_dumb_create - Create a dumb shmem buffer object
502 * @file: DRM file structure to create the dumb buffer for
506 * This function computes the pitch of the dumb buffer and rounds it up to an
507 * integer number of bytes per pixel. Drivers for hardware that doesn't have
508 * any additional restrictions on the pitch can directly use this function as
509 * their &drm_driver.dumb_create callback.
511 * For hardware with additional restrictions, drivers can adjust the fields
512 * set up by userspace before calling into this function.
515 * 0 on success or a negative error code on failure.
517 int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device *dev,
518 struct drm_mode_create_dumb *args)
520 u32 min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
521 struct drm_gem_shmem_object *shmem;
523 if (!args->pitch || !args->size) {
524 args->pitch = min_pitch;
525 args->size = PAGE_ALIGN(args->pitch * args->height);
527 /* ensure sane minimum values */
528 if (args->pitch < min_pitch)
529 args->pitch = min_pitch;
530 if (args->size < args->pitch * args->height)
531 args->size = PAGE_ALIGN(args->pitch * args->height);
534 shmem = drm_gem_shmem_create_with_handle(file, dev, args->size, &args->handle);
536 return PTR_ERR_OR_ZERO(shmem);
538 EXPORT_SYMBOL_GPL(drm_gem_shmem_dumb_create);
540 static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf)
542 struct vm_area_struct *vma = vmf->vma;
543 struct drm_gem_object *obj = vma->vm_private_data;
544 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
545 loff_t num_pages = obj->size >> PAGE_SHIFT;
550 /* We don't use vmf->pgoff since that has the fake offset */
551 page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT;
553 mutex_lock(&shmem->pages_lock);
555 if (page_offset >= num_pages ||
556 WARN_ON_ONCE(!shmem->pages) ||
558 ret = VM_FAULT_SIGBUS;
560 page = shmem->pages[page_offset];
562 ret = vmf_insert_pfn(vma, vmf->address, page_to_pfn(page));
565 mutex_unlock(&shmem->pages_lock);
570 static void drm_gem_shmem_vm_open(struct vm_area_struct *vma)
572 struct drm_gem_object *obj = vma->vm_private_data;
573 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
575 WARN_ON(shmem->base.import_attach);
577 mutex_lock(&shmem->pages_lock);
580 * We should have already pinned the pages when the buffer was first
581 * mmap'd, vm_open() just grabs an additional reference for the new
582 * mm the vma is getting copied into (ie. on fork()).
584 if (!WARN_ON_ONCE(!shmem->pages_use_count))
585 shmem->pages_use_count++;
587 mutex_unlock(&shmem->pages_lock);
589 drm_gem_vm_open(vma);
592 static void drm_gem_shmem_vm_close(struct vm_area_struct *vma)
594 struct drm_gem_object *obj = vma->vm_private_data;
595 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
597 drm_gem_shmem_put_pages(shmem);
598 drm_gem_vm_close(vma);
601 const struct vm_operations_struct drm_gem_shmem_vm_ops = {
602 .fault = drm_gem_shmem_fault,
603 .open = drm_gem_shmem_vm_open,
604 .close = drm_gem_shmem_vm_close,
606 EXPORT_SYMBOL_GPL(drm_gem_shmem_vm_ops);
609 * drm_gem_shmem_mmap - Memory-map a shmem GEM object
610 * @shmem: shmem GEM object
611 * @vma: VMA for the area to be mapped
613 * This function implements an augmented version of the GEM DRM file mmap
614 * operation for shmem objects.
617 * 0 on success or a negative error code on failure.
619 int drm_gem_shmem_mmap(struct drm_gem_shmem_object *shmem, struct vm_area_struct *vma)
621 struct drm_gem_object *obj = &shmem->base;
624 if (obj->import_attach) {
625 /* Drop the reference drm_gem_mmap_obj() acquired.*/
626 drm_gem_object_put(obj);
627 vma->vm_private_data = NULL;
629 return dma_buf_mmap(obj->dma_buf, vma, 0);
632 ret = drm_gem_shmem_get_pages(shmem);
636 vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
637 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
639 vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
643 EXPORT_SYMBOL_GPL(drm_gem_shmem_mmap);
646 * drm_gem_shmem_print_info() - Print &drm_gem_shmem_object info for debugfs
647 * @shmem: shmem GEM object
649 * @indent: Tab indentation level
651 void drm_gem_shmem_print_info(const struct drm_gem_shmem_object *shmem,
652 struct drm_printer *p, unsigned int indent)
654 drm_printf_indent(p, indent, "pages_use_count=%u\n", shmem->pages_use_count);
655 drm_printf_indent(p, indent, "vmap_use_count=%u\n", shmem->vmap_use_count);
656 drm_printf_indent(p, indent, "vaddr=%p\n", shmem->vaddr);
658 EXPORT_SYMBOL(drm_gem_shmem_print_info);
661 * drm_gem_shmem_get_sg_table - Provide a scatter/gather table of pinned
662 * pages for a shmem GEM object
663 * @shmem: shmem GEM object
665 * This function exports a scatter/gather table suitable for PRIME usage by
666 * calling the standard DMA mapping API.
668 * Drivers who need to acquire an scatter/gather table for objects need to call
669 * drm_gem_shmem_get_pages_sgt() instead.
672 * A pointer to the scatter/gather table of pinned pages or error pointer on failure.
674 struct sg_table *drm_gem_shmem_get_sg_table(struct drm_gem_shmem_object *shmem)
676 struct drm_gem_object *obj = &shmem->base;
678 WARN_ON(shmem->base.import_attach);
680 return drm_prime_pages_to_sg(obj->dev, shmem->pages, obj->size >> PAGE_SHIFT);
682 EXPORT_SYMBOL_GPL(drm_gem_shmem_get_sg_table);
685 * drm_gem_shmem_get_pages_sgt - Pin pages, dma map them, and return a
686 * scatter/gather table for a shmem GEM object.
687 * @shmem: shmem GEM object
689 * This function returns a scatter/gather table suitable for driver usage. If
690 * the sg table doesn't exist, the pages are pinned, dma-mapped, and a sg
693 * This is the main function for drivers to get at backing storage, and it hides
694 * and difference between dma-buf imported and natively allocated objects.
695 * drm_gem_shmem_get_sg_table() should not be directly called by drivers.
698 * A pointer to the scatter/gather table of pinned pages or errno on failure.
700 struct sg_table *drm_gem_shmem_get_pages_sgt(struct drm_gem_shmem_object *shmem)
702 struct drm_gem_object *obj = &shmem->base;
704 struct sg_table *sgt;
709 WARN_ON(obj->import_attach);
711 ret = drm_gem_shmem_get_pages(shmem);
715 sgt = drm_gem_shmem_get_sg_table(shmem);
720 /* Map the pages for use by the h/w. */
721 ret = dma_map_sgtable(obj->dev->dev, sgt, DMA_BIDIRECTIONAL, 0);
733 drm_gem_shmem_put_pages(shmem);
736 EXPORT_SYMBOL_GPL(drm_gem_shmem_get_pages_sgt);
739 * drm_gem_shmem_prime_import_sg_table - Produce a shmem GEM object from
740 * another driver's scatter/gather table of pinned pages
741 * @dev: Device to import into
742 * @attach: DMA-BUF attachment
743 * @sgt: Scatter/gather table of pinned pages
745 * This function imports a scatter/gather table exported via DMA-BUF by
746 * another driver. Drivers that use the shmem helpers should set this as their
747 * &drm_driver.gem_prime_import_sg_table callback.
750 * A pointer to a newly created GEM object or an ERR_PTR-encoded negative
751 * error code on failure.
753 struct drm_gem_object *
754 drm_gem_shmem_prime_import_sg_table(struct drm_device *dev,
755 struct dma_buf_attachment *attach,
756 struct sg_table *sgt)
758 size_t size = PAGE_ALIGN(attach->dmabuf->size);
759 struct drm_gem_shmem_object *shmem;
761 shmem = __drm_gem_shmem_create(dev, size, true);
763 return ERR_CAST(shmem);
767 DRM_DEBUG_PRIME("size = %zu\n", size);
771 EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import_sg_table);
773 MODULE_DESCRIPTION("DRM SHMEM memory-management helpers");
774 MODULE_IMPORT_NS(DMA_BUF);
775 MODULE_LICENSE("GPL v2");