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/mutex.h>
9 #include <linux/shmem_fs.h>
10 #include <linux/slab.h>
11 #include <linux/vmalloc.h>
14 #include <drm/drm_device.h>
15 #include <drm/drm_drv.h>
16 #include <drm/drm_gem_shmem_helper.h>
17 #include <drm/drm_prime.h>
18 #include <drm/drm_print.h>
23 * This library provides helpers for GEM objects backed by shmem buffers
24 * allocated using anonymous pageable memory.
27 static const struct drm_gem_object_funcs drm_gem_shmem_funcs = {
28 .free = drm_gem_shmem_free_object,
29 .print_info = drm_gem_shmem_print_info,
30 .pin = drm_gem_shmem_pin,
31 .unpin = drm_gem_shmem_unpin,
32 .get_sg_table = drm_gem_shmem_get_sg_table,
33 .vmap = drm_gem_shmem_vmap,
34 .vunmap = drm_gem_shmem_vunmap,
35 .mmap = drm_gem_shmem_mmap,
38 static struct drm_gem_shmem_object *
39 __drm_gem_shmem_create(struct drm_device *dev, size_t size, bool private)
41 struct drm_gem_shmem_object *shmem;
42 struct drm_gem_object *obj;
45 size = PAGE_ALIGN(size);
47 if (dev->driver->gem_create_object)
48 obj = dev->driver->gem_create_object(dev, size);
50 obj = kzalloc(sizeof(*shmem), GFP_KERNEL);
52 return ERR_PTR(-ENOMEM);
54 shmem = to_drm_gem_shmem_obj(obj);
57 obj->funcs = &drm_gem_shmem_funcs;
60 drm_gem_private_object_init(dev, obj, size);
61 shmem->map_wc = false; /* dma-buf mappings use always writecombine */
63 ret = drm_gem_object_init(dev, obj, size);
68 ret = drm_gem_create_mmap_offset(obj);
72 mutex_init(&shmem->pages_lock);
73 mutex_init(&shmem->vmap_lock);
74 INIT_LIST_HEAD(&shmem->madv_list);
78 * Our buffers are kept pinned, so allocating them
79 * from the MOVABLE zone is a really bad idea, and
80 * conflicts with CMA. See comments above new_inode()
81 * why this is required _and_ expected if you're
82 * going to pin these pages.
84 mapping_set_gfp_mask(obj->filp->f_mapping, GFP_HIGHUSER |
85 __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
91 drm_gem_object_release(obj);
98 * drm_gem_shmem_create - Allocate an object with the given size
100 * @size: Size of the object to allocate
102 * This function creates a shmem GEM object.
105 * A struct drm_gem_shmem_object * on success or an ERR_PTR()-encoded negative
106 * error code on failure.
108 struct drm_gem_shmem_object *drm_gem_shmem_create(struct drm_device *dev, size_t size)
110 return __drm_gem_shmem_create(dev, size, false);
112 EXPORT_SYMBOL_GPL(drm_gem_shmem_create);
115 * drm_gem_shmem_free_object - Free resources associated with a shmem GEM object
116 * @obj: GEM object to free
118 * This function cleans up the GEM object state and frees the memory used to
119 * store the object itself. It should be used to implement
120 * &drm_gem_object_funcs.free.
122 void drm_gem_shmem_free_object(struct drm_gem_object *obj)
124 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
126 WARN_ON(shmem->vmap_use_count);
128 if (obj->import_attach) {
129 drm_prime_gem_destroy(obj, shmem->sgt);
132 dma_unmap_sgtable(obj->dev->dev, shmem->sgt,
133 DMA_BIDIRECTIONAL, 0);
134 sg_free_table(shmem->sgt);
138 drm_gem_shmem_put_pages(shmem);
141 WARN_ON(shmem->pages_use_count);
143 drm_gem_object_release(obj);
144 mutex_destroy(&shmem->pages_lock);
145 mutex_destroy(&shmem->vmap_lock);
148 EXPORT_SYMBOL_GPL(drm_gem_shmem_free_object);
150 static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem)
152 struct drm_gem_object *obj = &shmem->base;
155 if (shmem->pages_use_count++ > 0)
158 pages = drm_gem_get_pages(obj);
160 DRM_DEBUG_KMS("Failed to get pages (%ld)\n", PTR_ERR(pages));
161 shmem->pages_use_count = 0;
162 return PTR_ERR(pages);
165 shmem->pages = pages;
171 * drm_gem_shmem_get_pages - Allocate backing pages for a shmem GEM object
172 * @shmem: shmem GEM object
174 * This function makes sure that backing pages exists for the shmem GEM object
175 * and increases the use count.
178 * 0 on success or a negative error code on failure.
180 int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem)
184 WARN_ON(shmem->base.import_attach);
186 ret = mutex_lock_interruptible(&shmem->pages_lock);
189 ret = drm_gem_shmem_get_pages_locked(shmem);
190 mutex_unlock(&shmem->pages_lock);
194 EXPORT_SYMBOL(drm_gem_shmem_get_pages);
196 static void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem)
198 struct drm_gem_object *obj = &shmem->base;
200 if (WARN_ON_ONCE(!shmem->pages_use_count))
203 if (--shmem->pages_use_count > 0)
206 drm_gem_put_pages(obj, shmem->pages,
207 shmem->pages_mark_dirty_on_put,
208 shmem->pages_mark_accessed_on_put);
213 * drm_gem_shmem_put_pages - Decrease use count on the backing pages for a shmem GEM object
214 * @shmem: shmem GEM object
216 * This function decreases the use count and puts the backing pages when use drops to zero.
218 void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem)
220 mutex_lock(&shmem->pages_lock);
221 drm_gem_shmem_put_pages_locked(shmem);
222 mutex_unlock(&shmem->pages_lock);
224 EXPORT_SYMBOL(drm_gem_shmem_put_pages);
227 * drm_gem_shmem_pin - Pin backing pages for a shmem GEM object
230 * This function makes sure the backing pages are pinned in memory while the
231 * buffer is exported. It should only be used to implement
232 * &drm_gem_object_funcs.pin.
235 * 0 on success or a negative error code on failure.
237 int drm_gem_shmem_pin(struct drm_gem_object *obj)
239 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
241 WARN_ON(shmem->base.import_attach);
243 return drm_gem_shmem_get_pages(shmem);
245 EXPORT_SYMBOL(drm_gem_shmem_pin);
248 * drm_gem_shmem_unpin - Unpin backing pages for a shmem GEM object
251 * This function removes the requirement that the backing pages are pinned in
252 * memory. It should only be used to implement &drm_gem_object_funcs.unpin.
254 void drm_gem_shmem_unpin(struct drm_gem_object *obj)
256 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
258 WARN_ON(shmem->base.import_attach);
260 drm_gem_shmem_put_pages(shmem);
262 EXPORT_SYMBOL(drm_gem_shmem_unpin);
264 static int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem, struct dma_buf_map *map)
266 struct drm_gem_object *obj = &shmem->base;
269 if (shmem->vmap_use_count++ > 0) {
270 dma_buf_map_set_vaddr(map, shmem->vaddr);
274 if (obj->import_attach) {
275 ret = dma_buf_vmap(obj->import_attach->dmabuf, map);
277 if (WARN_ON(map->is_iomem)) {
281 shmem->vaddr = map->vaddr;
284 pgprot_t prot = PAGE_KERNEL;
286 ret = drm_gem_shmem_get_pages(shmem);
291 prot = pgprot_writecombine(prot);
292 shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT,
297 dma_buf_map_set_vaddr(map, shmem->vaddr);
301 DRM_DEBUG_KMS("Failed to vmap pages, error %d\n", ret);
308 if (!obj->import_attach)
309 drm_gem_shmem_put_pages(shmem);
311 shmem->vmap_use_count = 0;
317 * drm_gem_shmem_vmap - Create a virtual mapping for a shmem GEM object
318 * @shmem: shmem GEM object
319 * @map: Returns the kernel virtual address of the SHMEM GEM object's backing
322 * This function makes sure that a contiguous kernel virtual address mapping
323 * exists for the buffer backing the shmem GEM object.
325 * This function can be used to implement &drm_gem_object_funcs.vmap. But it can
326 * also be called by drivers directly, in which case it will hide the
327 * differences between dma-buf imported and natively allocated objects.
329 * Acquired mappings should be cleaned up by calling drm_gem_shmem_vunmap().
332 * 0 on success or a negative error code on failure.
334 int drm_gem_shmem_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
336 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
339 ret = mutex_lock_interruptible(&shmem->vmap_lock);
342 ret = drm_gem_shmem_vmap_locked(shmem, map);
343 mutex_unlock(&shmem->vmap_lock);
347 EXPORT_SYMBOL(drm_gem_shmem_vmap);
349 static void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem,
350 struct dma_buf_map *map)
352 struct drm_gem_object *obj = &shmem->base;
354 if (WARN_ON_ONCE(!shmem->vmap_use_count))
357 if (--shmem->vmap_use_count > 0)
360 if (obj->import_attach) {
361 dma_buf_vunmap(obj->import_attach->dmabuf, map);
363 vunmap(shmem->vaddr);
364 drm_gem_shmem_put_pages(shmem);
371 * drm_gem_shmem_vunmap - Unmap a virtual mapping fo a shmem GEM object
372 * @shmem: shmem GEM object
373 * @map: Kernel virtual address where the SHMEM GEM object was mapped
375 * This function cleans up a kernel virtual address mapping acquired by
376 * drm_gem_shmem_vmap(). The mapping is only removed when the use count drops to
379 * This function can be used to implement &drm_gem_object_funcs.vmap. But it can
380 * also be called by drivers directly, in which case it will hide the
381 * differences between dma-buf imported and natively allocated objects.
383 void drm_gem_shmem_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map)
385 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
387 mutex_lock(&shmem->vmap_lock);
388 drm_gem_shmem_vunmap_locked(shmem, map);
389 mutex_unlock(&shmem->vmap_lock);
391 EXPORT_SYMBOL(drm_gem_shmem_vunmap);
393 struct drm_gem_shmem_object *
394 drm_gem_shmem_create_with_handle(struct drm_file *file_priv,
395 struct drm_device *dev, size_t size,
398 struct drm_gem_shmem_object *shmem;
401 shmem = drm_gem_shmem_create(dev, size);
406 * Allocate an id of idr table where the obj is registered
407 * and handle has the id what user can see.
409 ret = drm_gem_handle_create(file_priv, &shmem->base, handle);
410 /* drop reference from allocate - handle holds it now. */
411 drm_gem_object_put(&shmem->base);
417 EXPORT_SYMBOL(drm_gem_shmem_create_with_handle);
419 /* Update madvise status, returns true if not purged, else
422 int drm_gem_shmem_madvise(struct drm_gem_object *obj, int madv)
424 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
426 mutex_lock(&shmem->pages_lock);
428 if (shmem->madv >= 0)
433 mutex_unlock(&shmem->pages_lock);
437 EXPORT_SYMBOL(drm_gem_shmem_madvise);
439 void drm_gem_shmem_purge_locked(struct drm_gem_object *obj)
441 struct drm_device *dev = obj->dev;
442 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
444 WARN_ON(!drm_gem_shmem_is_purgeable(shmem));
446 dma_unmap_sgtable(obj->dev->dev, shmem->sgt, DMA_BIDIRECTIONAL, 0);
447 sg_free_table(shmem->sgt);
451 drm_gem_shmem_put_pages_locked(shmem);
455 drm_vma_node_unmap(&obj->vma_node, dev->anon_inode->i_mapping);
456 drm_gem_free_mmap_offset(obj);
458 /* Our goal here is to return as much of the memory as
459 * is possible back to the system as we are called from OOM.
460 * To do this we must instruct the shmfs to drop all of its
461 * backing pages, *now*.
463 shmem_truncate_range(file_inode(obj->filp), 0, (loff_t)-1);
465 invalidate_mapping_pages(file_inode(obj->filp)->i_mapping,
468 EXPORT_SYMBOL(drm_gem_shmem_purge_locked);
470 bool drm_gem_shmem_purge(struct drm_gem_object *obj)
472 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
474 if (!mutex_trylock(&shmem->pages_lock))
476 drm_gem_shmem_purge_locked(obj);
477 mutex_unlock(&shmem->pages_lock);
481 EXPORT_SYMBOL(drm_gem_shmem_purge);
484 * drm_gem_shmem_dumb_create - Create a dumb shmem buffer object
485 * @file: DRM file structure to create the dumb buffer for
489 * This function computes the pitch of the dumb buffer and rounds it up to an
490 * integer number of bytes per pixel. Drivers for hardware that doesn't have
491 * any additional restrictions on the pitch can directly use this function as
492 * their &drm_driver.dumb_create callback.
494 * For hardware with additional restrictions, drivers can adjust the fields
495 * set up by userspace before calling into this function.
498 * 0 on success or a negative error code on failure.
500 int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device *dev,
501 struct drm_mode_create_dumb *args)
503 u32 min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
504 struct drm_gem_shmem_object *shmem;
506 if (!args->pitch || !args->size) {
507 args->pitch = min_pitch;
508 args->size = args->pitch * args->height;
510 /* ensure sane minimum values */
511 if (args->pitch < min_pitch)
512 args->pitch = min_pitch;
513 if (args->size < args->pitch * args->height)
514 args->size = args->pitch * args->height;
517 shmem = drm_gem_shmem_create_with_handle(file, dev, args->size, &args->handle);
519 return PTR_ERR_OR_ZERO(shmem);
521 EXPORT_SYMBOL_GPL(drm_gem_shmem_dumb_create);
523 static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf)
525 struct vm_area_struct *vma = vmf->vma;
526 struct drm_gem_object *obj = vma->vm_private_data;
527 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
528 loff_t num_pages = obj->size >> PAGE_SHIFT;
533 /* We don't use vmf->pgoff since that has the fake offset */
534 page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT;
536 mutex_lock(&shmem->pages_lock);
538 if (page_offset >= num_pages ||
539 WARN_ON_ONCE(!shmem->pages) ||
541 ret = VM_FAULT_SIGBUS;
543 page = shmem->pages[page_offset];
545 ret = vmf_insert_page(vma, vmf->address, page);
548 mutex_unlock(&shmem->pages_lock);
553 static void drm_gem_shmem_vm_open(struct vm_area_struct *vma)
555 struct drm_gem_object *obj = vma->vm_private_data;
556 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
559 WARN_ON(shmem->base.import_attach);
561 ret = drm_gem_shmem_get_pages(shmem);
562 WARN_ON_ONCE(ret != 0);
564 drm_gem_vm_open(vma);
567 static void drm_gem_shmem_vm_close(struct vm_area_struct *vma)
569 struct drm_gem_object *obj = vma->vm_private_data;
570 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
572 drm_gem_shmem_put_pages(shmem);
573 drm_gem_vm_close(vma);
576 static const struct vm_operations_struct drm_gem_shmem_vm_ops = {
577 .fault = drm_gem_shmem_fault,
578 .open = drm_gem_shmem_vm_open,
579 .close = drm_gem_shmem_vm_close,
583 * drm_gem_shmem_mmap - Memory-map a shmem GEM object
585 * @vma: VMA for the area to be mapped
587 * This function implements an augmented version of the GEM DRM file mmap
588 * operation for shmem objects. Drivers which employ the shmem helpers should
589 * use this function as their &drm_gem_object_funcs.mmap handler.
592 * 0 on success or a negative error code on failure.
594 int drm_gem_shmem_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
596 struct drm_gem_shmem_object *shmem;
599 if (obj->import_attach) {
600 /* Drop the reference drm_gem_mmap_obj() acquired.*/
601 drm_gem_object_put(obj);
602 vma->vm_private_data = NULL;
604 return dma_buf_mmap(obj->dma_buf, vma, 0);
607 shmem = to_drm_gem_shmem_obj(obj);
609 ret = drm_gem_shmem_get_pages(shmem);
611 drm_gem_vm_close(vma);
615 vma->vm_flags |= VM_MIXEDMAP | VM_DONTEXPAND;
616 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
618 vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
619 vma->vm_ops = &drm_gem_shmem_vm_ops;
623 EXPORT_SYMBOL_GPL(drm_gem_shmem_mmap);
626 * drm_gem_shmem_print_info() - Print &drm_gem_shmem_object info for debugfs
628 * @indent: Tab indentation level
631 * This implements the &drm_gem_object_funcs.info callback.
633 void drm_gem_shmem_print_info(struct drm_printer *p, unsigned int indent,
634 const struct drm_gem_object *obj)
636 const struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
638 drm_printf_indent(p, indent, "pages_use_count=%u\n", shmem->pages_use_count);
639 drm_printf_indent(p, indent, "vmap_use_count=%u\n", shmem->vmap_use_count);
640 drm_printf_indent(p, indent, "vaddr=%p\n", shmem->vaddr);
642 EXPORT_SYMBOL(drm_gem_shmem_print_info);
645 * drm_gem_shmem_get_sg_table - Provide a scatter/gather table of pinned
646 * pages for a shmem GEM object
649 * This function exports a scatter/gather table suitable for PRIME usage by
650 * calling the standard DMA mapping API. Drivers should not call this function
651 * directly, instead it should only be used as an implementation for
652 * &drm_gem_object_funcs.get_sg_table.
654 * Drivers who need to acquire an scatter/gather table for objects need to call
655 * drm_gem_shmem_get_pages_sgt() instead.
658 * A pointer to the scatter/gather table of pinned pages or NULL on failure.
660 struct sg_table *drm_gem_shmem_get_sg_table(struct drm_gem_object *obj)
662 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
664 WARN_ON(shmem->base.import_attach);
666 return drm_prime_pages_to_sg(obj->dev, shmem->pages, obj->size >> PAGE_SHIFT);
668 EXPORT_SYMBOL_GPL(drm_gem_shmem_get_sg_table);
671 * drm_gem_shmem_get_pages_sgt - Pin pages, dma map them, and return a
672 * scatter/gather table for a shmem GEM object.
675 * This function returns a scatter/gather table suitable for driver usage. If
676 * the sg table doesn't exist, the pages are pinned, dma-mapped, and a sg
679 * This is the main function for drivers to get at backing storage, and it hides
680 * and difference between dma-buf imported and natively allocated objects.
681 * drm_gem_shmem_get_sg_table() should not be directly called by drivers.
684 * A pointer to the scatter/gather table of pinned pages or errno on failure.
686 struct sg_table *drm_gem_shmem_get_pages_sgt(struct drm_gem_object *obj)
689 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
690 struct sg_table *sgt;
695 WARN_ON(obj->import_attach);
697 ret = drm_gem_shmem_get_pages(shmem);
701 sgt = drm_gem_shmem_get_sg_table(&shmem->base);
706 /* Map the pages for use by the h/w. */
707 ret = dma_map_sgtable(obj->dev->dev, sgt, DMA_BIDIRECTIONAL, 0);
719 drm_gem_shmem_put_pages(shmem);
722 EXPORT_SYMBOL_GPL(drm_gem_shmem_get_pages_sgt);
725 * drm_gem_shmem_prime_import_sg_table - Produce a shmem GEM object from
726 * another driver's scatter/gather table of pinned pages
727 * @dev: Device to import into
728 * @attach: DMA-BUF attachment
729 * @sgt: Scatter/gather table of pinned pages
731 * This function imports a scatter/gather table exported via DMA-BUF by
732 * another driver. Drivers that use the shmem helpers should set this as their
733 * &drm_driver.gem_prime_import_sg_table callback.
736 * A pointer to a newly created GEM object or an ERR_PTR-encoded negative
737 * error code on failure.
739 struct drm_gem_object *
740 drm_gem_shmem_prime_import_sg_table(struct drm_device *dev,
741 struct dma_buf_attachment *attach,
742 struct sg_table *sgt)
744 size_t size = PAGE_ALIGN(attach->dmabuf->size);
745 struct drm_gem_shmem_object *shmem;
747 shmem = __drm_gem_shmem_create(dev, size, true);
749 return ERR_CAST(shmem);
753 DRM_DEBUG_PRIME("size = %zu\n", size);
757 EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import_sg_table);