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>
12 #include <linux/module.h>
15 #include <asm/set_memory.h>
19 #include <drm/drm_device.h>
20 #include <drm/drm_drv.h>
21 #include <drm/drm_gem_shmem_helper.h>
22 #include <drm/drm_prime.h>
23 #include <drm/drm_print.h>
25 MODULE_IMPORT_NS(DMA_BUF);
30 * This library provides helpers for GEM objects backed by shmem buffers
31 * allocated using anonymous pageable memory.
34 static const struct drm_gem_object_funcs drm_gem_shmem_funcs = {
35 .free = drm_gem_shmem_free_object,
36 .print_info = drm_gem_shmem_print_info,
37 .pin = drm_gem_shmem_pin,
38 .unpin = drm_gem_shmem_unpin,
39 .get_sg_table = drm_gem_shmem_get_sg_table,
40 .vmap = drm_gem_shmem_vmap,
41 .vunmap = drm_gem_shmem_vunmap,
42 .mmap = drm_gem_shmem_mmap,
45 static struct drm_gem_shmem_object *
46 __drm_gem_shmem_create(struct drm_device *dev, size_t size, bool private)
48 struct drm_gem_shmem_object *shmem;
49 struct drm_gem_object *obj;
52 size = PAGE_ALIGN(size);
54 if (dev->driver->gem_create_object)
55 obj = dev->driver->gem_create_object(dev, size);
57 obj = kzalloc(sizeof(*shmem), GFP_KERNEL);
59 return ERR_PTR(-ENOMEM);
61 shmem = to_drm_gem_shmem_obj(obj);
64 obj->funcs = &drm_gem_shmem_funcs;
67 drm_gem_private_object_init(dev, obj, size);
68 shmem->map_wc = false; /* dma-buf mappings use always writecombine */
70 ret = drm_gem_object_init(dev, obj, size);
75 ret = drm_gem_create_mmap_offset(obj);
79 mutex_init(&shmem->pages_lock);
80 mutex_init(&shmem->vmap_lock);
81 INIT_LIST_HEAD(&shmem->madv_list);
85 * Our buffers are kept pinned, so allocating them
86 * from the MOVABLE zone is a really bad idea, and
87 * conflicts with CMA. See comments above new_inode()
88 * why this is required _and_ expected if you're
89 * going to pin these pages.
91 mapping_set_gfp_mask(obj->filp->f_mapping, GFP_HIGHUSER |
92 __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
98 drm_gem_object_release(obj);
105 * drm_gem_shmem_create - Allocate an object with the given size
107 * @size: Size of the object to allocate
109 * This function creates a shmem GEM object.
112 * A struct drm_gem_shmem_object * on success or an ERR_PTR()-encoded negative
113 * error code on failure.
115 struct drm_gem_shmem_object *drm_gem_shmem_create(struct drm_device *dev, size_t size)
117 return __drm_gem_shmem_create(dev, size, false);
119 EXPORT_SYMBOL_GPL(drm_gem_shmem_create);
122 * drm_gem_shmem_free_object - Free resources associated with a shmem GEM object
123 * @obj: GEM object to free
125 * This function cleans up the GEM object state and frees the memory used to
126 * store the object itself. It should be used to implement
127 * &drm_gem_object_funcs.free.
129 void drm_gem_shmem_free_object(struct drm_gem_object *obj)
131 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
133 WARN_ON(shmem->vmap_use_count);
135 if (obj->import_attach) {
136 drm_prime_gem_destroy(obj, shmem->sgt);
139 dma_unmap_sgtable(obj->dev->dev, shmem->sgt,
140 DMA_BIDIRECTIONAL, 0);
141 sg_free_table(shmem->sgt);
145 drm_gem_shmem_put_pages(shmem);
148 WARN_ON(shmem->pages_use_count);
150 drm_gem_object_release(obj);
151 mutex_destroy(&shmem->pages_lock);
152 mutex_destroy(&shmem->vmap_lock);
155 EXPORT_SYMBOL_GPL(drm_gem_shmem_free_object);
157 static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem)
159 struct drm_gem_object *obj = &shmem->base;
162 if (shmem->pages_use_count++ > 0)
165 pages = drm_gem_get_pages(obj);
167 DRM_DEBUG_KMS("Failed to get pages (%ld)\n", PTR_ERR(pages));
168 shmem->pages_use_count = 0;
169 return PTR_ERR(pages);
173 * TODO: Allocating WC pages which are correctly flushed is only
174 * supported on x86. Ideal solution would be a GFP_WC flag, which also
175 * ttm_pool.c could use.
179 set_pages_array_wc(pages, obj->size >> PAGE_SHIFT);
182 shmem->pages = pages;
188 * drm_gem_shmem_get_pages - Allocate backing pages for a shmem GEM object
189 * @shmem: shmem GEM object
191 * This function makes sure that backing pages exists for the shmem GEM object
192 * and increases the use count.
195 * 0 on success or a negative error code on failure.
197 int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem)
201 WARN_ON(shmem->base.import_attach);
203 ret = mutex_lock_interruptible(&shmem->pages_lock);
206 ret = drm_gem_shmem_get_pages_locked(shmem);
207 mutex_unlock(&shmem->pages_lock);
211 EXPORT_SYMBOL(drm_gem_shmem_get_pages);
213 static void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem)
215 struct drm_gem_object *obj = &shmem->base;
217 if (WARN_ON_ONCE(!shmem->pages_use_count))
220 if (--shmem->pages_use_count > 0)
225 set_pages_array_wb(shmem->pages, obj->size >> PAGE_SHIFT);
228 drm_gem_put_pages(obj, shmem->pages,
229 shmem->pages_mark_dirty_on_put,
230 shmem->pages_mark_accessed_on_put);
235 * drm_gem_shmem_put_pages - Decrease use count on the backing pages for a shmem GEM object
236 * @shmem: shmem GEM object
238 * This function decreases the use count and puts the backing pages when use drops to zero.
240 void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem)
242 mutex_lock(&shmem->pages_lock);
243 drm_gem_shmem_put_pages_locked(shmem);
244 mutex_unlock(&shmem->pages_lock);
246 EXPORT_SYMBOL(drm_gem_shmem_put_pages);
249 * drm_gem_shmem_pin - Pin backing pages for a shmem GEM object
252 * This function makes sure the backing pages are pinned in memory while the
253 * buffer is exported. It should only be used to implement
254 * &drm_gem_object_funcs.pin.
257 * 0 on success or a negative error code on failure.
259 int drm_gem_shmem_pin(struct drm_gem_object *obj)
261 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
263 WARN_ON(shmem->base.import_attach);
265 return drm_gem_shmem_get_pages(shmem);
267 EXPORT_SYMBOL(drm_gem_shmem_pin);
270 * drm_gem_shmem_unpin - Unpin backing pages for a shmem GEM object
273 * This function removes the requirement that the backing pages are pinned in
274 * memory. It should only be used to implement &drm_gem_object_funcs.unpin.
276 void drm_gem_shmem_unpin(struct drm_gem_object *obj)
278 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
280 WARN_ON(shmem->base.import_attach);
282 drm_gem_shmem_put_pages(shmem);
284 EXPORT_SYMBOL(drm_gem_shmem_unpin);
286 static int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem, struct dma_buf_map *map)
288 struct drm_gem_object *obj = &shmem->base;
291 if (shmem->vmap_use_count++ > 0) {
292 dma_buf_map_set_vaddr(map, shmem->vaddr);
296 if (obj->import_attach) {
297 ret = dma_buf_vmap(obj->import_attach->dmabuf, map);
299 if (WARN_ON(map->is_iomem)) {
303 shmem->vaddr = map->vaddr;
306 pgprot_t prot = PAGE_KERNEL;
308 ret = drm_gem_shmem_get_pages(shmem);
313 prot = pgprot_writecombine(prot);
314 shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT,
319 dma_buf_map_set_vaddr(map, shmem->vaddr);
323 DRM_DEBUG_KMS("Failed to vmap pages, error %d\n", ret);
330 if (!obj->import_attach)
331 drm_gem_shmem_put_pages(shmem);
333 shmem->vmap_use_count = 0;
339 * drm_gem_shmem_vmap - Create a virtual mapping for a shmem GEM object
340 * @shmem: shmem GEM object
341 * @map: Returns the kernel virtual address of the SHMEM GEM object's backing
344 * This function makes sure that a contiguous kernel virtual address mapping
345 * exists for the buffer backing the shmem GEM object.
347 * This function can be used to implement &drm_gem_object_funcs.vmap. But it can
348 * also be called by drivers directly, in which case it will hide the
349 * differences between dma-buf imported and natively allocated objects.
351 * Acquired mappings should be cleaned up by calling drm_gem_shmem_vunmap().
354 * 0 on success or a negative error code on failure.
356 int drm_gem_shmem_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
358 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
361 ret = mutex_lock_interruptible(&shmem->vmap_lock);
364 ret = drm_gem_shmem_vmap_locked(shmem, map);
365 mutex_unlock(&shmem->vmap_lock);
369 EXPORT_SYMBOL(drm_gem_shmem_vmap);
371 static void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem,
372 struct dma_buf_map *map)
374 struct drm_gem_object *obj = &shmem->base;
376 if (WARN_ON_ONCE(!shmem->vmap_use_count))
379 if (--shmem->vmap_use_count > 0)
382 if (obj->import_attach) {
383 dma_buf_vunmap(obj->import_attach->dmabuf, map);
385 vunmap(shmem->vaddr);
386 drm_gem_shmem_put_pages(shmem);
393 * drm_gem_shmem_vunmap - Unmap a virtual mapping for a shmem GEM object
394 * @shmem: shmem GEM object
395 * @map: Kernel virtual address where the SHMEM GEM object was mapped
397 * This function cleans up a kernel virtual address mapping acquired by
398 * drm_gem_shmem_vmap(). The mapping is only removed when the use count drops to
401 * This function can be used to implement &drm_gem_object_funcs.vmap. But it can
402 * also be called by drivers directly, in which case it will hide the
403 * differences between dma-buf imported and natively allocated objects.
405 void drm_gem_shmem_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map)
407 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
409 mutex_lock(&shmem->vmap_lock);
410 drm_gem_shmem_vunmap_locked(shmem, map);
411 mutex_unlock(&shmem->vmap_lock);
413 EXPORT_SYMBOL(drm_gem_shmem_vunmap);
415 struct drm_gem_shmem_object *
416 drm_gem_shmem_create_with_handle(struct drm_file *file_priv,
417 struct drm_device *dev, size_t size,
420 struct drm_gem_shmem_object *shmem;
423 shmem = drm_gem_shmem_create(dev, size);
428 * Allocate an id of idr table where the obj is registered
429 * and handle has the id what user can see.
431 ret = drm_gem_handle_create(file_priv, &shmem->base, handle);
432 /* drop reference from allocate - handle holds it now. */
433 drm_gem_object_put(&shmem->base);
439 EXPORT_SYMBOL(drm_gem_shmem_create_with_handle);
441 /* Update madvise status, returns true if not purged, else
444 int drm_gem_shmem_madvise(struct drm_gem_object *obj, int madv)
446 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
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_object *obj)
463 struct drm_device *dev = obj->dev;
464 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
466 WARN_ON(!drm_gem_shmem_is_purgeable(shmem));
468 dma_unmap_sgtable(obj->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,
490 EXPORT_SYMBOL(drm_gem_shmem_purge_locked);
492 bool drm_gem_shmem_purge(struct drm_gem_object *obj)
494 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
496 if (!mutex_trylock(&shmem->pages_lock))
498 drm_gem_shmem_purge_locked(obj);
499 mutex_unlock(&shmem->pages_lock);
503 EXPORT_SYMBOL(drm_gem_shmem_purge);
506 * drm_gem_shmem_dumb_create - Create a dumb shmem buffer object
507 * @file: DRM file structure to create the dumb buffer for
511 * This function computes the pitch of the dumb buffer and rounds it up to an
512 * integer number of bytes per pixel. Drivers for hardware that doesn't have
513 * any additional restrictions on the pitch can directly use this function as
514 * their &drm_driver.dumb_create callback.
516 * For hardware with additional restrictions, drivers can adjust the fields
517 * set up by userspace before calling into this function.
520 * 0 on success or a negative error code on failure.
522 int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device *dev,
523 struct drm_mode_create_dumb *args)
525 u32 min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
526 struct drm_gem_shmem_object *shmem;
528 if (!args->pitch || !args->size) {
529 args->pitch = min_pitch;
530 args->size = PAGE_ALIGN(args->pitch * args->height);
532 /* ensure sane minimum values */
533 if (args->pitch < min_pitch)
534 args->pitch = min_pitch;
535 if (args->size < args->pitch * args->height)
536 args->size = PAGE_ALIGN(args->pitch * args->height);
539 shmem = drm_gem_shmem_create_with_handle(file, dev, args->size, &args->handle);
541 return PTR_ERR_OR_ZERO(shmem);
543 EXPORT_SYMBOL_GPL(drm_gem_shmem_dumb_create);
545 static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf)
547 struct vm_area_struct *vma = vmf->vma;
548 struct drm_gem_object *obj = vma->vm_private_data;
549 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
550 loff_t num_pages = obj->size >> PAGE_SHIFT;
555 /* We don't use vmf->pgoff since that has the fake offset */
556 page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT;
558 mutex_lock(&shmem->pages_lock);
560 if (page_offset >= num_pages ||
561 WARN_ON_ONCE(!shmem->pages) ||
563 ret = VM_FAULT_SIGBUS;
565 page = shmem->pages[page_offset];
567 ret = vmf_insert_pfn(vma, vmf->address, page_to_pfn(page));
570 mutex_unlock(&shmem->pages_lock);
575 static void drm_gem_shmem_vm_open(struct vm_area_struct *vma)
577 struct drm_gem_object *obj = vma->vm_private_data;
578 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
581 WARN_ON(shmem->base.import_attach);
583 ret = drm_gem_shmem_get_pages(shmem);
584 WARN_ON_ONCE(ret != 0);
586 drm_gem_vm_open(vma);
589 static void drm_gem_shmem_vm_close(struct vm_area_struct *vma)
591 struct drm_gem_object *obj = vma->vm_private_data;
592 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
594 drm_gem_shmem_put_pages(shmem);
595 drm_gem_vm_close(vma);
598 static const struct vm_operations_struct drm_gem_shmem_vm_ops = {
599 .fault = drm_gem_shmem_fault,
600 .open = drm_gem_shmem_vm_open,
601 .close = drm_gem_shmem_vm_close,
605 * drm_gem_shmem_mmap - Memory-map a shmem GEM object
607 * @vma: VMA for the area to be mapped
609 * This function implements an augmented version of the GEM DRM file mmap
610 * operation for shmem objects. Drivers which employ the shmem helpers should
611 * use this function as their &drm_gem_object_funcs.mmap handler.
614 * 0 on success or a negative error code on failure.
616 int drm_gem_shmem_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
618 struct drm_gem_shmem_object *shmem;
621 if (obj->import_attach) {
622 /* Drop the reference drm_gem_mmap_obj() acquired.*/
623 drm_gem_object_put(obj);
624 vma->vm_private_data = NULL;
626 return dma_buf_mmap(obj->dma_buf, vma, 0);
629 shmem = to_drm_gem_shmem_obj(obj);
631 ret = drm_gem_shmem_get_pages(shmem);
633 drm_gem_vm_close(vma);
637 vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND;
638 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
640 vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
641 vma->vm_ops = &drm_gem_shmem_vm_ops;
645 EXPORT_SYMBOL_GPL(drm_gem_shmem_mmap);
648 * drm_gem_shmem_print_info() - Print &drm_gem_shmem_object info for debugfs
650 * @indent: Tab indentation level
653 * This implements the &drm_gem_object_funcs.info callback.
655 void drm_gem_shmem_print_info(struct drm_printer *p, unsigned int indent,
656 const struct drm_gem_object *obj)
658 const struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
660 drm_printf_indent(p, indent, "pages_use_count=%u\n", shmem->pages_use_count);
661 drm_printf_indent(p, indent, "vmap_use_count=%u\n", shmem->vmap_use_count);
662 drm_printf_indent(p, indent, "vaddr=%p\n", shmem->vaddr);
664 EXPORT_SYMBOL(drm_gem_shmem_print_info);
667 * drm_gem_shmem_get_sg_table - Provide a scatter/gather table of pinned
668 * pages for a shmem GEM object
671 * This function exports a scatter/gather table suitable for PRIME usage by
672 * calling the standard DMA mapping API. Drivers should not call this function
673 * directly, instead it should only be used as an implementation for
674 * &drm_gem_object_funcs.get_sg_table.
676 * Drivers who need to acquire an scatter/gather table for objects need to call
677 * drm_gem_shmem_get_pages_sgt() instead.
680 * A pointer to the scatter/gather table of pinned pages or NULL on failure.
682 struct sg_table *drm_gem_shmem_get_sg_table(struct drm_gem_object *obj)
684 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
686 WARN_ON(shmem->base.import_attach);
688 return drm_prime_pages_to_sg(obj->dev, shmem->pages, obj->size >> PAGE_SHIFT);
690 EXPORT_SYMBOL_GPL(drm_gem_shmem_get_sg_table);
693 * drm_gem_shmem_get_pages_sgt - Pin pages, dma map them, and return a
694 * scatter/gather table for a shmem GEM object.
697 * This function returns a scatter/gather table suitable for driver usage. If
698 * the sg table doesn't exist, the pages are pinned, dma-mapped, and a sg
701 * This is the main function for drivers to get at backing storage, and it hides
702 * and difference between dma-buf imported and natively allocated objects.
703 * drm_gem_shmem_get_sg_table() should not be directly called by drivers.
706 * A pointer to the scatter/gather table of pinned pages or errno on failure.
708 struct sg_table *drm_gem_shmem_get_pages_sgt(struct drm_gem_object *obj)
711 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
712 struct sg_table *sgt;
717 WARN_ON(obj->import_attach);
719 ret = drm_gem_shmem_get_pages(shmem);
723 sgt = drm_gem_shmem_get_sg_table(&shmem->base);
728 /* Map the pages for use by the h/w. */
729 ret = dma_map_sgtable(obj->dev->dev, sgt, DMA_BIDIRECTIONAL, 0);
741 drm_gem_shmem_put_pages(shmem);
744 EXPORT_SYMBOL_GPL(drm_gem_shmem_get_pages_sgt);
747 * drm_gem_shmem_prime_import_sg_table - Produce a shmem GEM object from
748 * another driver's scatter/gather table of pinned pages
749 * @dev: Device to import into
750 * @attach: DMA-BUF attachment
751 * @sgt: Scatter/gather table of pinned pages
753 * This function imports a scatter/gather table exported via DMA-BUF by
754 * another driver. Drivers that use the shmem helpers should set this as their
755 * &drm_driver.gem_prime_import_sg_table callback.
758 * A pointer to a newly created GEM object or an ERR_PTR-encoded negative
759 * error code on failure.
761 struct drm_gem_object *
762 drm_gem_shmem_prime_import_sg_table(struct drm_device *dev,
763 struct dma_buf_attachment *attach,
764 struct sg_table *sgt)
766 size_t size = PAGE_ALIGN(attach->dmabuf->size);
767 struct drm_gem_shmem_object *shmem;
769 shmem = __drm_gem_shmem_create(dev, size, true);
771 return ERR_CAST(shmem);
775 DRM_DEBUG_PRIME("size = %zu\n", size);
779 EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import_sg_table);