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,
39 * drm_gem_shmem_create - Allocate an object with the given size
41 * @size: Size of the object to allocate
43 * This function creates a shmem GEM object.
46 * A struct drm_gem_shmem_object * on success or an ERR_PTR()-encoded negative
47 * error code on failure.
49 struct drm_gem_shmem_object *drm_gem_shmem_create(struct drm_device *dev, size_t size)
51 struct drm_gem_shmem_object *shmem;
52 struct drm_gem_object *obj;
55 size = PAGE_ALIGN(size);
57 if (dev->driver->gem_create_object)
58 obj = dev->driver->gem_create_object(dev, size);
60 obj = kzalloc(sizeof(*shmem), GFP_KERNEL);
62 return ERR_PTR(-ENOMEM);
65 obj->funcs = &drm_gem_shmem_funcs;
67 ret = drm_gem_object_init(dev, obj, size);
71 ret = drm_gem_create_mmap_offset(obj);
75 shmem = to_drm_gem_shmem_obj(obj);
76 mutex_init(&shmem->pages_lock);
77 mutex_init(&shmem->vmap_lock);
78 INIT_LIST_HEAD(&shmem->madv_list);
81 * Our buffers are kept pinned, so allocating them
82 * from the MOVABLE zone is a really bad idea, and
83 * conflicts with CMA. See comments above new_inode()
84 * why this is required _and_ expected if you're
85 * going to pin these pages.
87 mapping_set_gfp_mask(obj->filp->f_mapping, GFP_HIGHUSER |
88 __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
93 drm_gem_object_release(obj);
99 EXPORT_SYMBOL_GPL(drm_gem_shmem_create);
102 * drm_gem_shmem_free_object - Free resources associated with a shmem GEM object
103 * @obj: GEM object to free
105 * This function cleans up the GEM object state and frees the memory used to
106 * store the object itself.
108 void drm_gem_shmem_free_object(struct drm_gem_object *obj)
110 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
112 WARN_ON(shmem->vmap_use_count);
114 if (obj->import_attach) {
115 shmem->pages_use_count--;
116 drm_prime_gem_destroy(obj, shmem->sgt);
117 kvfree(shmem->pages);
120 dma_unmap_sg(obj->dev->dev, shmem->sgt->sgl,
121 shmem->sgt->nents, DMA_BIDIRECTIONAL);
122 sg_free_table(shmem->sgt);
126 drm_gem_shmem_put_pages(shmem);
129 WARN_ON(shmem->pages_use_count);
131 drm_gem_object_release(obj);
132 mutex_destroy(&shmem->pages_lock);
133 mutex_destroy(&shmem->vmap_lock);
136 EXPORT_SYMBOL_GPL(drm_gem_shmem_free_object);
138 static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem)
140 struct drm_gem_object *obj = &shmem->base;
143 if (shmem->pages_use_count++ > 0)
146 pages = drm_gem_get_pages(obj);
148 DRM_DEBUG_KMS("Failed to get pages (%ld)\n", PTR_ERR(pages));
149 shmem->pages_use_count = 0;
150 return PTR_ERR(pages);
153 shmem->pages = pages;
159 * drm_gem_shmem_get_pages - Allocate backing pages for a shmem GEM object
160 * @shmem: shmem GEM object
162 * This function makes sure that backing pages exists for the shmem GEM object
163 * and increases the use count.
166 * 0 on success or a negative error code on failure.
168 int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem)
172 ret = mutex_lock_interruptible(&shmem->pages_lock);
175 ret = drm_gem_shmem_get_pages_locked(shmem);
176 mutex_unlock(&shmem->pages_lock);
180 EXPORT_SYMBOL(drm_gem_shmem_get_pages);
182 static void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem)
184 struct drm_gem_object *obj = &shmem->base;
186 if (WARN_ON_ONCE(!shmem->pages_use_count))
189 if (--shmem->pages_use_count > 0)
192 drm_gem_put_pages(obj, shmem->pages,
193 shmem->pages_mark_dirty_on_put,
194 shmem->pages_mark_accessed_on_put);
199 * drm_gem_shmem_put_pages - Decrease use count on the backing pages for a shmem GEM object
200 * @shmem: shmem GEM object
202 * This function decreases the use count and puts the backing pages when use drops to zero.
204 void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem)
206 mutex_lock(&shmem->pages_lock);
207 drm_gem_shmem_put_pages_locked(shmem);
208 mutex_unlock(&shmem->pages_lock);
210 EXPORT_SYMBOL(drm_gem_shmem_put_pages);
213 * drm_gem_shmem_pin - Pin backing pages for a shmem GEM object
216 * This function makes sure the backing pages are pinned in memory while the
217 * buffer is exported.
220 * 0 on success or a negative error code on failure.
222 int drm_gem_shmem_pin(struct drm_gem_object *obj)
224 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
226 return drm_gem_shmem_get_pages(shmem);
228 EXPORT_SYMBOL(drm_gem_shmem_pin);
231 * drm_gem_shmem_unpin - Unpin backing pages for a shmem GEM object
234 * This function removes the requirement that the backing pages are pinned in
237 void drm_gem_shmem_unpin(struct drm_gem_object *obj)
239 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
241 drm_gem_shmem_put_pages(shmem);
243 EXPORT_SYMBOL(drm_gem_shmem_unpin);
245 static void *drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem)
247 struct drm_gem_object *obj = &shmem->base;
250 if (shmem->vmap_use_count++ > 0)
253 ret = drm_gem_shmem_get_pages(shmem);
257 if (obj->import_attach)
258 shmem->vaddr = dma_buf_vmap(obj->import_attach->dmabuf);
260 shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT,
261 VM_MAP, pgprot_writecombine(PAGE_KERNEL));
264 DRM_DEBUG_KMS("Failed to vmap pages\n");
272 drm_gem_shmem_put_pages(shmem);
274 shmem->vmap_use_count = 0;
280 * drm_gem_shmem_vmap - Create a virtual mapping for a shmem GEM object
281 * @shmem: shmem GEM object
283 * This function makes sure that a virtual address exists for the buffer backing
284 * the shmem GEM object.
287 * 0 on success or a negative error code on failure.
289 void *drm_gem_shmem_vmap(struct drm_gem_object *obj)
291 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
295 ret = mutex_lock_interruptible(&shmem->vmap_lock);
298 vaddr = drm_gem_shmem_vmap_locked(shmem);
299 mutex_unlock(&shmem->vmap_lock);
303 EXPORT_SYMBOL(drm_gem_shmem_vmap);
305 static void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem)
307 struct drm_gem_object *obj = &shmem->base;
309 if (WARN_ON_ONCE(!shmem->vmap_use_count))
312 if (--shmem->vmap_use_count > 0)
315 if (obj->import_attach)
316 dma_buf_vunmap(obj->import_attach->dmabuf, shmem->vaddr);
318 vunmap(shmem->vaddr);
321 drm_gem_shmem_put_pages(shmem);
325 * drm_gem_shmem_vunmap - Unmap a virtual mapping fo a shmem GEM object
326 * @shmem: shmem GEM object
328 * This function removes the virtual address when use count drops to zero.
330 void drm_gem_shmem_vunmap(struct drm_gem_object *obj, void *vaddr)
332 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
334 mutex_lock(&shmem->vmap_lock);
335 drm_gem_shmem_vunmap_locked(shmem);
336 mutex_unlock(&shmem->vmap_lock);
338 EXPORT_SYMBOL(drm_gem_shmem_vunmap);
340 struct drm_gem_shmem_object *
341 drm_gem_shmem_create_with_handle(struct drm_file *file_priv,
342 struct drm_device *dev, size_t size,
345 struct drm_gem_shmem_object *shmem;
348 shmem = drm_gem_shmem_create(dev, size);
353 * Allocate an id of idr table where the obj is registered
354 * and handle has the id what user can see.
356 ret = drm_gem_handle_create(file_priv, &shmem->base, handle);
357 /* drop reference from allocate - handle holds it now. */
358 drm_gem_object_put_unlocked(&shmem->base);
364 EXPORT_SYMBOL(drm_gem_shmem_create_with_handle);
366 /* Update madvise status, returns true if not purged, else
369 int drm_gem_shmem_madvise(struct drm_gem_object *obj, int madv)
371 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
373 mutex_lock(&shmem->pages_lock);
375 if (shmem->madv >= 0)
380 mutex_unlock(&shmem->pages_lock);
384 EXPORT_SYMBOL(drm_gem_shmem_madvise);
386 void drm_gem_shmem_purge_locked(struct drm_gem_object *obj)
388 struct drm_device *dev = obj->dev;
389 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
391 WARN_ON(!drm_gem_shmem_is_purgeable(shmem));
393 dma_unmap_sg(obj->dev->dev, shmem->sgt->sgl,
394 shmem->sgt->nents, DMA_BIDIRECTIONAL);
395 sg_free_table(shmem->sgt);
399 drm_gem_shmem_put_pages_locked(shmem);
403 drm_vma_node_unmap(&obj->vma_node, dev->anon_inode->i_mapping);
404 drm_gem_free_mmap_offset(obj);
406 /* Our goal here is to return as much of the memory as
407 * is possible back to the system as we are called from OOM.
408 * To do this we must instruct the shmfs to drop all of its
409 * backing pages, *now*.
411 shmem_truncate_range(file_inode(obj->filp), 0, (loff_t)-1);
413 invalidate_mapping_pages(file_inode(obj->filp)->i_mapping,
416 EXPORT_SYMBOL(drm_gem_shmem_purge_locked);
418 bool drm_gem_shmem_purge(struct drm_gem_object *obj)
420 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
422 if (!mutex_trylock(&shmem->pages_lock))
424 drm_gem_shmem_purge_locked(obj);
425 mutex_unlock(&shmem->pages_lock);
429 EXPORT_SYMBOL(drm_gem_shmem_purge);
432 * drm_gem_shmem_dumb_create - Create a dumb shmem buffer object
433 * @file: DRM file structure to create the dumb buffer for
437 * This function computes the pitch of the dumb buffer and rounds it up to an
438 * integer number of bytes per pixel. Drivers for hardware that doesn't have
439 * any additional restrictions on the pitch can directly use this function as
440 * their &drm_driver.dumb_create callback.
442 * For hardware with additional restrictions, drivers can adjust the fields
443 * set up by userspace before calling into this function.
446 * 0 on success or a negative error code on failure.
448 int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device *dev,
449 struct drm_mode_create_dumb *args)
451 u32 min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
452 struct drm_gem_shmem_object *shmem;
454 if (!args->pitch || !args->size) {
455 args->pitch = min_pitch;
456 args->size = args->pitch * args->height;
458 /* ensure sane minimum values */
459 if (args->pitch < min_pitch)
460 args->pitch = min_pitch;
461 if (args->size < args->pitch * args->height)
462 args->size = args->pitch * args->height;
465 shmem = drm_gem_shmem_create_with_handle(file, dev, args->size, &args->handle);
467 return PTR_ERR_OR_ZERO(shmem);
469 EXPORT_SYMBOL_GPL(drm_gem_shmem_dumb_create);
471 static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf)
473 struct vm_area_struct *vma = vmf->vma;
474 struct drm_gem_object *obj = vma->vm_private_data;
475 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
476 loff_t num_pages = obj->size >> PAGE_SHIFT;
479 if (vmf->pgoff >= num_pages || WARN_ON_ONCE(!shmem->pages))
480 return VM_FAULT_SIGBUS;
482 page = shmem->pages[vmf->pgoff];
484 return vmf_insert_page(vma, vmf->address, page);
487 static void drm_gem_shmem_vm_open(struct vm_area_struct *vma)
489 struct drm_gem_object *obj = vma->vm_private_data;
490 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
493 ret = drm_gem_shmem_get_pages(shmem);
494 WARN_ON_ONCE(ret != 0);
496 drm_gem_vm_open(vma);
499 static void drm_gem_shmem_vm_close(struct vm_area_struct *vma)
501 struct drm_gem_object *obj = vma->vm_private_data;
502 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
504 drm_gem_shmem_put_pages(shmem);
505 drm_gem_vm_close(vma);
508 static const struct vm_operations_struct drm_gem_shmem_vm_ops = {
509 .fault = drm_gem_shmem_fault,
510 .open = drm_gem_shmem_vm_open,
511 .close = drm_gem_shmem_vm_close,
515 * drm_gem_shmem_mmap - Memory-map a shmem GEM object
517 * @vma: VMA for the area to be mapped
519 * This function implements an augmented version of the GEM DRM file mmap
520 * operation for shmem objects. Drivers which employ the shmem helpers should
521 * use this function as their &drm_gem_object_funcs.mmap handler.
524 * 0 on success or a negative error code on failure.
526 int drm_gem_shmem_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
528 struct drm_gem_shmem_object *shmem;
531 shmem = to_drm_gem_shmem_obj(obj);
533 ret = drm_gem_shmem_get_pages(shmem);
535 drm_gem_vm_close(vma);
539 vma->vm_flags |= VM_MIXEDMAP | VM_DONTEXPAND;
540 vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
541 vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
542 vma->vm_ops = &drm_gem_shmem_vm_ops;
546 EXPORT_SYMBOL_GPL(drm_gem_shmem_mmap);
549 * drm_gem_shmem_print_info() - Print &drm_gem_shmem_object info for debugfs
551 * @indent: Tab indentation level
554 void drm_gem_shmem_print_info(struct drm_printer *p, unsigned int indent,
555 const struct drm_gem_object *obj)
557 const struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
559 drm_printf_indent(p, indent, "pages_use_count=%u\n", shmem->pages_use_count);
560 drm_printf_indent(p, indent, "vmap_use_count=%u\n", shmem->vmap_use_count);
561 drm_printf_indent(p, indent, "vaddr=%p\n", shmem->vaddr);
563 EXPORT_SYMBOL(drm_gem_shmem_print_info);
566 * drm_gem_shmem_get_sg_table - Provide a scatter/gather table of pinned
567 * pages for a shmem GEM object
570 * This function exports a scatter/gather table suitable for PRIME usage by
571 * calling the standard DMA mapping API.
574 * A pointer to the scatter/gather table of pinned pages or NULL on failure.
576 struct sg_table *drm_gem_shmem_get_sg_table(struct drm_gem_object *obj)
578 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
580 return drm_prime_pages_to_sg(shmem->pages, obj->size >> PAGE_SHIFT);
582 EXPORT_SYMBOL_GPL(drm_gem_shmem_get_sg_table);
585 * drm_gem_shmem_get_pages_sgt - Pin pages, dma map them, and return a
586 * scatter/gather table for a shmem GEM object.
589 * This function returns a scatter/gather table suitable for driver usage. If
590 * the sg table doesn't exist, the pages are pinned, dma-mapped, and a sg
594 * A pointer to the scatter/gather table of pinned pages or errno on failure.
596 struct sg_table *drm_gem_shmem_get_pages_sgt(struct drm_gem_object *obj)
599 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
600 struct sg_table *sgt;
605 WARN_ON(obj->import_attach);
607 ret = drm_gem_shmem_get_pages(shmem);
611 sgt = drm_gem_shmem_get_sg_table(&shmem->base);
616 /* Map the pages for use by the h/w. */
617 dma_map_sg(obj->dev->dev, sgt->sgl, sgt->nents, DMA_BIDIRECTIONAL);
624 drm_gem_shmem_put_pages(shmem);
627 EXPORT_SYMBOL_GPL(drm_gem_shmem_get_pages_sgt);
630 * drm_gem_shmem_prime_import_sg_table - Produce a shmem GEM object from
631 * another driver's scatter/gather table of pinned pages
632 * @dev: Device to import into
633 * @attach: DMA-BUF attachment
634 * @sgt: Scatter/gather table of pinned pages
636 * This function imports a scatter/gather table exported via DMA-BUF by
637 * another driver. Drivers that use the shmem helpers should set this as their
638 * &drm_driver.gem_prime_import_sg_table callback.
641 * A pointer to a newly created GEM object or an ERR_PTR-encoded negative
642 * error code on failure.
644 struct drm_gem_object *
645 drm_gem_shmem_prime_import_sg_table(struct drm_device *dev,
646 struct dma_buf_attachment *attach,
647 struct sg_table *sgt)
649 size_t size = PAGE_ALIGN(attach->dmabuf->size);
650 size_t npages = size >> PAGE_SHIFT;
651 struct drm_gem_shmem_object *shmem;
654 shmem = drm_gem_shmem_create(dev, size);
656 return ERR_CAST(shmem);
658 shmem->pages = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
664 ret = drm_prime_sg_to_page_addr_arrays(sgt, shmem->pages, NULL, npages);
669 shmem->pages_use_count = 1; /* Permanently pinned from our point of view */
671 DRM_DEBUG_PRIME("size = %zu\n", size);
676 kvfree(shmem->pages);
678 drm_gem_object_put_unlocked(&shmem->base);
682 EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import_sg_table);