2 * Copyright © 2008 Intel Corporation
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
24 * Eric Anholt <eric@anholt.net>
28 #include <linux/types.h>
29 #include <linux/slab.h>
31 #include <linux/uaccess.h>
33 #include <linux/file.h>
34 #include <linux/module.h>
35 #include <linux/mman.h>
36 #include <linux/pagemap.h>
37 #include <linux/shmem_fs.h>
38 #include <linux/dma-buf.h>
43 * This file provides some of the base ioctls and library routines for
44 * the graphics memory manager implemented by each device driver.
46 * Because various devices have different requirements in terms of
47 * synchronization and migration strategies, implementing that is left up to
48 * the driver, and all that the general API provides should be generic --
49 * allocating objects, reading/writing data with the cpu, freeing objects.
50 * Even there, platform-dependent optimizations for reading/writing data with
51 * the CPU mean we'll likely hook those out to driver-specific calls. However,
52 * the DRI2 implementation wants to have at least allocate/mmap be generic.
54 * The goal was to have swap-backed object allocation managed through
55 * struct file. However, file descriptors as handles to a struct file have
57 * - Process limits prevent more than 1024 or so being used at a time by
59 * - Inability to allocate high fds will aggravate the X Server's select()
60 * handling, and likely that of many GL client applications as well.
62 * This led to a plan of using our own integer IDs (called handles, following
63 * DRM terminology) to mimic fds, and implement the fd syscalls we need as
64 * ioctls. The objects themselves will still include the struct file so
65 * that we can transition to fds if the required kernel infrastructure shows
66 * up at a later date, and as our interface with shmfs for memory allocation.
70 * We make up offsets for buffer objects so we can recognize them at
74 /* pgoff in mmap is an unsigned long, so we need to make sure that
75 * the faked up offset will fit
78 #if BITS_PER_LONG == 64
79 #define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFFUL >> PAGE_SHIFT) + 1)
80 #define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFFUL >> PAGE_SHIFT) * 16)
82 #define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFUL >> PAGE_SHIFT) + 1)
83 #define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFUL >> PAGE_SHIFT) * 16)
87 * Initialize the GEM device fields
91 drm_gem_init(struct drm_device *dev)
93 struct drm_gem_mm *mm;
95 spin_lock_init(&dev->object_name_lock);
96 idr_init(&dev->object_name_idr);
98 mm = kzalloc(sizeof(struct drm_gem_mm), GFP_KERNEL);
100 DRM_ERROR("out of memory\n");
104 dev->mm_private = mm;
106 if (drm_ht_create(&mm->offset_hash, 12)) {
111 drm_mm_init(&mm->offset_manager, DRM_FILE_PAGE_OFFSET_START,
112 DRM_FILE_PAGE_OFFSET_SIZE);
118 drm_gem_destroy(struct drm_device *dev)
120 struct drm_gem_mm *mm = dev->mm_private;
122 drm_mm_takedown(&mm->offset_manager);
123 drm_ht_remove(&mm->offset_hash);
125 dev->mm_private = NULL;
129 * Initialize an already allocated GEM object of the specified size with
130 * shmfs backing store.
132 int drm_gem_object_init(struct drm_device *dev,
133 struct drm_gem_object *obj, size_t size)
137 filp = shmem_file_setup("drm mm object", size, VM_NORESERVE);
139 return PTR_ERR(filp);
141 drm_gem_private_object_init(dev, obj, size);
146 EXPORT_SYMBOL(drm_gem_object_init);
149 * Initialize an already allocated GEM object of the specified size with
150 * no GEM provided backing store. Instead the caller is responsible for
151 * backing the object and handling it.
153 void drm_gem_private_object_init(struct drm_device *dev,
154 struct drm_gem_object *obj, size_t size)
156 BUG_ON((size & (PAGE_SIZE - 1)) != 0);
161 kref_init(&obj->refcount);
162 atomic_set(&obj->handle_count, 0);
165 EXPORT_SYMBOL(drm_gem_private_object_init);
168 * Allocate a GEM object of the specified size with shmfs backing store
170 struct drm_gem_object *
171 drm_gem_object_alloc(struct drm_device *dev, size_t size)
173 struct drm_gem_object *obj;
175 obj = kzalloc(sizeof(*obj), GFP_KERNEL);
179 if (drm_gem_object_init(dev, obj, size) != 0)
182 if (dev->driver->gem_init_object != NULL &&
183 dev->driver->gem_init_object(obj) != 0) {
188 /* Object_init mangles the global counters - readjust them. */
194 EXPORT_SYMBOL(drm_gem_object_alloc);
197 drm_gem_remove_prime_handles(struct drm_gem_object *obj, struct drm_file *filp)
199 if (obj->import_attach) {
200 drm_prime_remove_buf_handle(&filp->prime,
201 obj->import_attach->dmabuf);
203 if (obj->export_dma_buf) {
204 drm_prime_remove_buf_handle(&filp->prime,
205 obj->export_dma_buf);
210 * Removes the mapping from handle to filp for this object.
213 drm_gem_handle_delete(struct drm_file *filp, u32 handle)
215 struct drm_device *dev;
216 struct drm_gem_object *obj;
218 /* This is gross. The idr system doesn't let us try a delete and
219 * return an error code. It just spews if you fail at deleting.
220 * So, we have to grab a lock around finding the object and then
221 * doing the delete on it and dropping the refcount, or the user
222 * could race us to double-decrement the refcount and cause a
223 * use-after-free later. Given the frequency of our handle lookups,
224 * we may want to use ida for number allocation and a hash table
225 * for the pointers, anyway.
227 spin_lock(&filp->table_lock);
229 /* Check if we currently have a reference on the object */
230 obj = idr_find(&filp->object_idr, handle);
232 spin_unlock(&filp->table_lock);
237 /* Release reference and decrement refcount. */
238 idr_remove(&filp->object_idr, handle);
239 spin_unlock(&filp->table_lock);
241 drm_gem_remove_prime_handles(obj, filp);
243 if (dev->driver->gem_close_object)
244 dev->driver->gem_close_object(obj, filp);
245 drm_gem_object_handle_unreference_unlocked(obj);
249 EXPORT_SYMBOL(drm_gem_handle_delete);
252 * Create a handle for this object. This adds a handle reference
253 * to the object, which includes a regular reference count. Callers
254 * will likely want to dereference the object afterwards.
257 drm_gem_handle_create(struct drm_file *file_priv,
258 struct drm_gem_object *obj,
261 struct drm_device *dev = obj->dev;
265 * Get the user-visible handle using idr. Preload and perform
266 * allocation under our spinlock.
268 idr_preload(GFP_KERNEL);
269 spin_lock(&file_priv->table_lock);
271 ret = idr_alloc(&file_priv->object_idr, obj, 1, 0, GFP_NOWAIT);
273 spin_unlock(&file_priv->table_lock);
279 drm_gem_object_handle_reference(obj);
281 if (dev->driver->gem_open_object) {
282 ret = dev->driver->gem_open_object(obj, file_priv);
284 drm_gem_handle_delete(file_priv, *handlep);
291 EXPORT_SYMBOL(drm_gem_handle_create);
295 * drm_gem_free_mmap_offset - release a fake mmap offset for an object
296 * @obj: obj in question
298 * This routine frees fake offsets allocated by drm_gem_create_mmap_offset().
301 drm_gem_free_mmap_offset(struct drm_gem_object *obj)
303 struct drm_device *dev = obj->dev;
304 struct drm_gem_mm *mm = dev->mm_private;
305 struct drm_map_list *list = &obj->map_list;
307 drm_ht_remove_item(&mm->offset_hash, &list->hash);
308 drm_mm_put_block(list->file_offset_node);
312 EXPORT_SYMBOL(drm_gem_free_mmap_offset);
315 * drm_gem_create_mmap_offset - create a fake mmap offset for an object
316 * @obj: obj in question
318 * GEM memory mapping works by handing back to userspace a fake mmap offset
319 * it can use in a subsequent mmap(2) call. The DRM core code then looks
320 * up the object based on the offset and sets up the various memory mapping
323 * This routine allocates and attaches a fake offset for @obj.
326 drm_gem_create_mmap_offset(struct drm_gem_object *obj)
328 struct drm_device *dev = obj->dev;
329 struct drm_gem_mm *mm = dev->mm_private;
330 struct drm_map_list *list;
331 struct drm_local_map *map;
334 /* Set the object up for mmap'ing */
335 list = &obj->map_list;
336 list->map = kzalloc(sizeof(struct drm_map_list), GFP_KERNEL);
341 map->type = _DRM_GEM;
342 map->size = obj->size;
345 /* Get a DRM GEM mmap offset allocated... */
346 list->file_offset_node = drm_mm_search_free(&mm->offset_manager,
347 obj->size / PAGE_SIZE, 0, false);
349 if (!list->file_offset_node) {
350 DRM_ERROR("failed to allocate offset for bo %d\n", obj->name);
355 list->file_offset_node = drm_mm_get_block(list->file_offset_node,
356 obj->size / PAGE_SIZE, 0);
357 if (!list->file_offset_node) {
362 list->hash.key = list->file_offset_node->start;
363 ret = drm_ht_insert_item(&mm->offset_hash, &list->hash);
365 DRM_ERROR("failed to add to map hash\n");
372 drm_mm_put_block(list->file_offset_node);
379 EXPORT_SYMBOL(drm_gem_create_mmap_offset);
381 /** Returns a reference to the object named by the handle. */
382 struct drm_gem_object *
383 drm_gem_object_lookup(struct drm_device *dev, struct drm_file *filp,
386 struct drm_gem_object *obj;
388 spin_lock(&filp->table_lock);
390 /* Check if we currently have a reference on the object */
391 obj = idr_find(&filp->object_idr, handle);
393 spin_unlock(&filp->table_lock);
397 drm_gem_object_reference(obj);
399 spin_unlock(&filp->table_lock);
403 EXPORT_SYMBOL(drm_gem_object_lookup);
406 * Releases the handle to an mm object.
409 drm_gem_close_ioctl(struct drm_device *dev, void *data,
410 struct drm_file *file_priv)
412 struct drm_gem_close *args = data;
415 if (!(dev->driver->driver_features & DRIVER_GEM))
418 ret = drm_gem_handle_delete(file_priv, args->handle);
424 * Create a global name for an object, returning the name.
426 * Note that the name does not hold a reference; when the object
427 * is freed, the name goes away.
430 drm_gem_flink_ioctl(struct drm_device *dev, void *data,
431 struct drm_file *file_priv)
433 struct drm_gem_flink *args = data;
434 struct drm_gem_object *obj;
437 if (!(dev->driver->driver_features & DRIVER_GEM))
440 obj = drm_gem_object_lookup(dev, file_priv, args->handle);
444 idr_preload(GFP_KERNEL);
445 spin_lock(&dev->object_name_lock);
447 ret = idr_alloc(&dev->object_name_idr, obj, 1, 0, GFP_NOWAIT);
453 /* Allocate a reference for the name table. */
454 drm_gem_object_reference(obj);
457 args->name = (uint64_t) obj->name;
461 spin_unlock(&dev->object_name_lock);
463 drm_gem_object_unreference_unlocked(obj);
468 * Open an object using the global name, returning a handle and the size.
470 * This handle (of course) holds a reference to the object, so the object
471 * will not go away until the handle is deleted.
474 drm_gem_open_ioctl(struct drm_device *dev, void *data,
475 struct drm_file *file_priv)
477 struct drm_gem_open *args = data;
478 struct drm_gem_object *obj;
482 if (!(dev->driver->driver_features & DRIVER_GEM))
485 spin_lock(&dev->object_name_lock);
486 obj = idr_find(&dev->object_name_idr, (int) args->name);
488 drm_gem_object_reference(obj);
489 spin_unlock(&dev->object_name_lock);
493 ret = drm_gem_handle_create(file_priv, obj, &handle);
494 drm_gem_object_unreference_unlocked(obj);
498 args->handle = handle;
499 args->size = obj->size;
505 * Called at device open time, sets up the structure for handling refcounting
509 drm_gem_open(struct drm_device *dev, struct drm_file *file_private)
511 idr_init(&file_private->object_idr);
512 spin_lock_init(&file_private->table_lock);
516 * Called at device close to release the file's
517 * handle references on objects.
520 drm_gem_object_release_handle(int id, void *ptr, void *data)
522 struct drm_file *file_priv = data;
523 struct drm_gem_object *obj = ptr;
524 struct drm_device *dev = obj->dev;
526 drm_gem_remove_prime_handles(obj, file_priv);
528 if (dev->driver->gem_close_object)
529 dev->driver->gem_close_object(obj, file_priv);
531 drm_gem_object_handle_unreference_unlocked(obj);
537 * Called at close time when the filp is going away.
539 * Releases any remaining references on objects by this filp.
542 drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
544 idr_for_each(&file_private->object_idr,
545 &drm_gem_object_release_handle, file_private);
546 idr_destroy(&file_private->object_idr);
550 drm_gem_object_release(struct drm_gem_object *obj)
555 EXPORT_SYMBOL(drm_gem_object_release);
558 * Called after the last reference to the object has been lost.
559 * Must be called holding struct_ mutex
564 drm_gem_object_free(struct kref *kref)
566 struct drm_gem_object *obj = (struct drm_gem_object *) kref;
567 struct drm_device *dev = obj->dev;
569 BUG_ON(!mutex_is_locked(&dev->struct_mutex));
571 if (dev->driver->gem_free_object != NULL)
572 dev->driver->gem_free_object(obj);
574 EXPORT_SYMBOL(drm_gem_object_free);
576 static void drm_gem_object_ref_bug(struct kref *list_kref)
582 * Called after the last handle to the object has been closed
584 * Removes any name for the object. Note that this must be
585 * called before drm_gem_object_free or we'll be touching
588 void drm_gem_object_handle_free(struct drm_gem_object *obj)
590 struct drm_device *dev = obj->dev;
592 /* Remove any name for this object */
593 spin_lock(&dev->object_name_lock);
595 idr_remove(&dev->object_name_idr, obj->name);
597 spin_unlock(&dev->object_name_lock);
599 * The object name held a reference to this object, drop
602 * This cannot be the last reference, since the handle holds one too.
604 kref_put(&obj->refcount, drm_gem_object_ref_bug);
606 spin_unlock(&dev->object_name_lock);
609 EXPORT_SYMBOL(drm_gem_object_handle_free);
611 void drm_gem_vm_open(struct vm_area_struct *vma)
613 struct drm_gem_object *obj = vma->vm_private_data;
615 drm_gem_object_reference(obj);
617 mutex_lock(&obj->dev->struct_mutex);
618 drm_vm_open_locked(obj->dev, vma);
619 mutex_unlock(&obj->dev->struct_mutex);
621 EXPORT_SYMBOL(drm_gem_vm_open);
623 void drm_gem_vm_close(struct vm_area_struct *vma)
625 struct drm_gem_object *obj = vma->vm_private_data;
626 struct drm_device *dev = obj->dev;
628 mutex_lock(&dev->struct_mutex);
629 drm_vm_close_locked(obj->dev, vma);
630 drm_gem_object_unreference(obj);
631 mutex_unlock(&dev->struct_mutex);
633 EXPORT_SYMBOL(drm_gem_vm_close);
636 * drm_gem_mmap_obj - memory map a GEM object
637 * @obj: the GEM object to map
638 * @obj_size: the object size to be mapped, in bytes
639 * @vma: VMA for the area to be mapped
641 * Set up the VMA to prepare mapping of the GEM object using the gem_vm_ops
642 * provided by the driver. Depending on their requirements, drivers can either
643 * provide a fault handler in their gem_vm_ops (in which case any accesses to
644 * the object will be trapped, to perform migration, GTT binding, surface
645 * register allocation, or performance monitoring), or mmap the buffer memory
646 * synchronously after calling drm_gem_mmap_obj.
648 * This function is mainly intended to implement the DMABUF mmap operation, when
649 * the GEM object is not looked up based on its fake offset. To implement the
650 * DRM mmap operation, drivers should use the drm_gem_mmap() function.
652 * NOTE: This function has to be protected with dev->struct_mutex
654 * Return 0 or success or -EINVAL if the object size is smaller than the VMA
655 * size, or if no gem_vm_ops are provided.
657 int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
658 struct vm_area_struct *vma)
660 struct drm_device *dev = obj->dev;
662 lockdep_assert_held(&dev->struct_mutex);
664 /* Check for valid size. */
665 if (obj_size < vma->vm_end - vma->vm_start)
668 if (!dev->driver->gem_vm_ops)
671 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
672 vma->vm_ops = dev->driver->gem_vm_ops;
673 vma->vm_private_data = obj;
674 vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
676 /* Take a ref for this mapping of the object, so that the fault
677 * handler can dereference the mmap offset's pointer to the object.
678 * This reference is cleaned up by the corresponding vm_close
679 * (which should happen whether the vma was created by this call, or
680 * by a vm_open due to mremap or partial unmap or whatever).
682 drm_gem_object_reference(obj);
684 drm_vm_open_locked(dev, vma);
687 EXPORT_SYMBOL(drm_gem_mmap_obj);
690 * drm_gem_mmap - memory map routine for GEM objects
691 * @filp: DRM file pointer
692 * @vma: VMA for the area to be mapped
694 * If a driver supports GEM object mapping, mmap calls on the DRM file
695 * descriptor will end up here.
697 * Look up the GEM object based on the offset passed in (vma->vm_pgoff will
698 * contain the fake offset we created when the GTT map ioctl was called on
699 * the object) and map it with a call to drm_gem_mmap_obj().
701 int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
703 struct drm_file *priv = filp->private_data;
704 struct drm_device *dev = priv->minor->dev;
705 struct drm_gem_mm *mm = dev->mm_private;
706 struct drm_local_map *map = NULL;
707 struct drm_hash_item *hash;
710 if (drm_device_is_unplugged(dev))
713 mutex_lock(&dev->struct_mutex);
715 if (drm_ht_find_item(&mm->offset_hash, vma->vm_pgoff, &hash)) {
716 mutex_unlock(&dev->struct_mutex);
717 return drm_mmap(filp, vma);
720 map = drm_hash_entry(hash, struct drm_map_list, hash)->map;
722 ((map->flags & _DRM_RESTRICTED) && !capable(CAP_SYS_ADMIN))) {
727 ret = drm_gem_mmap_obj(map->handle, map->size, vma);
730 mutex_unlock(&dev->struct_mutex);
734 EXPORT_SYMBOL(drm_gem_mmap);