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 mutex_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 if (drm_mm_init(&mm->offset_manager, DRM_FILE_PAGE_OFFSET_START,
112 DRM_FILE_PAGE_OFFSET_SIZE)) {
113 drm_ht_remove(&mm->offset_hash);
122 drm_gem_destroy(struct drm_device *dev)
124 struct drm_gem_mm *mm = dev->mm_private;
126 drm_mm_takedown(&mm->offset_manager);
127 drm_ht_remove(&mm->offset_hash);
129 dev->mm_private = NULL;
133 * Initialize an already allocated GEM object of the specified size with
134 * shmfs backing store.
136 int drm_gem_object_init(struct drm_device *dev,
137 struct drm_gem_object *obj, size_t size)
141 filp = shmem_file_setup("drm mm object", size, VM_NORESERVE);
143 return PTR_ERR(filp);
145 drm_gem_private_object_init(dev, obj, size);
150 EXPORT_SYMBOL(drm_gem_object_init);
153 * Initialize an already allocated GEM object of the specified size with
154 * no GEM provided backing store. Instead the caller is responsible for
155 * backing the object and handling it.
157 void drm_gem_private_object_init(struct drm_device *dev,
158 struct drm_gem_object *obj, size_t size)
160 BUG_ON((size & (PAGE_SIZE - 1)) != 0);
165 kref_init(&obj->refcount);
166 obj->handle_count = 0;
169 EXPORT_SYMBOL(drm_gem_private_object_init);
172 * Allocate a GEM object of the specified size with shmfs backing store
174 struct drm_gem_object *
175 drm_gem_object_alloc(struct drm_device *dev, size_t size)
177 struct drm_gem_object *obj;
179 obj = kzalloc(sizeof(*obj), GFP_KERNEL);
183 if (drm_gem_object_init(dev, obj, size) != 0)
186 if (dev->driver->gem_init_object != NULL &&
187 dev->driver->gem_init_object(obj) != 0) {
192 /* Object_init mangles the global counters - readjust them. */
198 EXPORT_SYMBOL(drm_gem_object_alloc);
201 drm_gem_remove_prime_handles(struct drm_gem_object *obj, struct drm_file *filp)
203 if (obj->import_attach) {
204 drm_prime_remove_buf_handle(&filp->prime,
205 obj->import_attach->dmabuf);
207 if (obj->export_dma_buf) {
208 drm_prime_remove_buf_handle(&filp->prime,
209 obj->export_dma_buf);
213 static void drm_gem_object_ref_bug(struct kref *list_kref)
219 * Called after the last handle to the object has been closed
221 * Removes any name for the object. Note that this must be
222 * called before drm_gem_object_free or we'll be touching
225 static void drm_gem_object_handle_free(struct drm_gem_object *obj)
227 struct drm_device *dev = obj->dev;
229 /* Remove any name for this object */
231 idr_remove(&dev->object_name_idr, obj->name);
234 * The object name held a reference to this object, drop
237 * This cannot be the last reference, since the handle holds one too.
239 kref_put(&obj->refcount, drm_gem_object_ref_bug);
244 drm_gem_object_handle_unreference_unlocked(struct drm_gem_object *obj)
246 if (WARN_ON(obj->handle_count == 0))
250 * Must bump handle count first as this may be the last
251 * ref, in which case the object would disappear before we
255 mutex_lock(&obj->dev->object_name_lock);
256 if (--obj->handle_count == 0)
257 drm_gem_object_handle_free(obj);
258 mutex_unlock(&obj->dev->object_name_lock);
260 drm_gem_object_unreference_unlocked(obj);
264 * Removes the mapping from handle to filp for this object.
267 drm_gem_handle_delete(struct drm_file *filp, u32 handle)
269 struct drm_device *dev;
270 struct drm_gem_object *obj;
272 /* This is gross. The idr system doesn't let us try a delete and
273 * return an error code. It just spews if you fail at deleting.
274 * So, we have to grab a lock around finding the object and then
275 * doing the delete on it and dropping the refcount, or the user
276 * could race us to double-decrement the refcount and cause a
277 * use-after-free later. Given the frequency of our handle lookups,
278 * we may want to use ida for number allocation and a hash table
279 * for the pointers, anyway.
281 spin_lock(&filp->table_lock);
283 /* Check if we currently have a reference on the object */
284 obj = idr_find(&filp->object_idr, handle);
286 spin_unlock(&filp->table_lock);
291 DRM_DEBUG("%s:hdl[%d]obj[0x%x]\n", __func__, handle, (int)obj);
293 /* Release reference and decrement refcount. */
294 idr_remove(&filp->object_idr, handle);
295 spin_unlock(&filp->table_lock);
297 drm_gem_remove_prime_handles(obj, filp);
299 if (dev->driver->gem_close_object)
300 dev->driver->gem_close_object(obj, filp);
301 drm_gem_object_handle_unreference_unlocked(obj);
305 EXPORT_SYMBOL(drm_gem_handle_delete);
308 * drm_gem_handle_create_tail - internal functions to create a handle
310 * This expects the dev->object_name_lock to be held already and will drop it
311 * before returning. Used to avoid races in establishing new handles when
312 * importing an object from either an flink name or a dma-buf.
315 drm_gem_handle_create_tail(struct drm_file *file_priv,
316 struct drm_gem_object *obj,
319 struct drm_device *dev = obj->dev;
322 WARN_ON(!mutex_is_locked(&dev->object_name_lock));
325 * Get the user-visible handle using idr. Preload and perform
326 * allocation under our spinlock.
328 idr_preload(GFP_KERNEL);
329 spin_lock(&file_priv->table_lock);
331 ret = idr_alloc(&file_priv->object_idr, obj, 1, 0, GFP_NOWAIT);
332 drm_gem_object_reference(obj);
334 spin_unlock(&file_priv->table_lock);
336 mutex_unlock(&dev->object_name_lock);
338 drm_gem_object_handle_unreference_unlocked(obj);
344 if (dev->driver->gem_open_object) {
345 ret = dev->driver->gem_open_object(obj, file_priv);
347 drm_gem_handle_delete(file_priv, *handlep);
356 * Create a handle for this object. This adds a handle reference
357 * to the object, which includes a regular reference count. Callers
358 * will likely want to dereference the object afterwards.
361 drm_gem_handle_create(struct drm_file *file_priv,
362 struct drm_gem_object *obj,
365 mutex_lock(&obj->dev->object_name_lock);
367 return drm_gem_handle_create_tail(file_priv, obj, handlep);
369 EXPORT_SYMBOL(drm_gem_handle_create);
373 * drm_gem_free_mmap_offset - release a fake mmap offset for an object
374 * @obj: obj in question
376 * This routine frees fake offsets allocated by drm_gem_create_mmap_offset().
379 drm_gem_free_mmap_offset(struct drm_gem_object *obj)
381 struct drm_device *dev = obj->dev;
382 struct drm_gem_mm *mm = dev->mm_private;
383 struct drm_map_list *list = &obj->map_list;
385 drm_ht_remove_item(&mm->offset_hash, &list->hash);
386 drm_mm_put_block(list->file_offset_node);
390 EXPORT_SYMBOL(drm_gem_free_mmap_offset);
393 * drm_gem_create_mmap_offset - create a fake mmap offset for an object
394 * @obj: obj in question
396 * GEM memory mapping works by handing back to userspace a fake mmap offset
397 * it can use in a subsequent mmap(2) call. The DRM core code then looks
398 * up the object based on the offset and sets up the various memory mapping
401 * This routine allocates and attaches a fake offset for @obj.
404 drm_gem_create_mmap_offset(struct drm_gem_object *obj)
406 struct drm_device *dev = obj->dev;
407 struct drm_gem_mm *mm = dev->mm_private;
408 struct drm_map_list *list;
409 struct drm_local_map *map;
412 /* Set the object up for mmap'ing */
413 list = &obj->map_list;
414 list->map = kzalloc(sizeof(struct drm_map_list), GFP_KERNEL);
419 map->type = _DRM_GEM;
420 map->size = obj->size;
423 /* Get a DRM GEM mmap offset allocated... */
424 list->file_offset_node = drm_mm_search_free(&mm->offset_manager,
425 obj->size / PAGE_SIZE, 0, false);
427 if (!list->file_offset_node) {
428 DRM_ERROR("failed to allocate offset for bo %d\n", obj->name);
433 list->file_offset_node = drm_mm_get_block(list->file_offset_node,
434 obj->size / PAGE_SIZE, 0);
435 if (!list->file_offset_node) {
440 list->hash.key = list->file_offset_node->start;
441 ret = drm_ht_insert_item(&mm->offset_hash, &list->hash);
443 DRM_ERROR("failed to add to map hash\n");
450 drm_mm_put_block(list->file_offset_node);
457 EXPORT_SYMBOL(drm_gem_create_mmap_offset);
459 /** Returns a reference to the object named by the handle. */
460 struct drm_gem_object *
461 drm_gem_object_lookup(struct drm_device *dev, struct drm_file *filp,
464 struct drm_gem_object *obj;
466 spin_lock(&filp->table_lock);
468 /* Check if we currently have a reference on the object */
469 obj = idr_find(&filp->object_idr, handle);
471 spin_unlock(&filp->table_lock);
475 drm_gem_object_reference(obj);
477 spin_unlock(&filp->table_lock);
481 EXPORT_SYMBOL(drm_gem_object_lookup);
484 * Releases the handle to an mm object.
487 drm_gem_close_ioctl(struct drm_device *dev, void *data,
488 struct drm_file *file_priv)
490 struct drm_gem_close *args = data;
493 if (!(dev->driver->driver_features & DRIVER_GEM))
496 ret = drm_gem_handle_delete(file_priv, args->handle);
502 * Create a global name for an object, returning the name.
504 * Note that the name does not hold a reference; when the object
505 * is freed, the name goes away.
508 drm_gem_flink_ioctl(struct drm_device *dev, void *data,
509 struct drm_file *file_priv)
511 struct drm_gem_flink *args = data;
512 struct drm_gem_object *obj;
515 if (!(dev->driver->driver_features & DRIVER_GEM))
518 obj = drm_gem_object_lookup(dev, file_priv, args->handle);
522 mutex_lock(&dev->object_name_lock);
523 idr_preload(GFP_KERNEL);
524 /* prevent races with concurrent gem_close. */
525 if (obj->handle_count == 0) {
531 ret = idr_alloc(&dev->object_name_idr, obj, 1, 0, GFP_NOWAIT);
537 /* Allocate a reference for the name table. */
538 drm_gem_object_reference(obj);
541 args->name = (uint64_t) obj->name;
546 mutex_unlock(&dev->object_name_lock);
547 drm_gem_object_unreference_unlocked(obj);
549 DRM_DEBUG("%s:hdl[%d]obj[0x%x]name[%d]\n",
550 __func__, (int) args->handle, (int)obj, args->name);
556 * Open an object using the global name, returning a handle and the size.
558 * This handle (of course) holds a reference to the object, so the object
559 * will not go away until the handle is deleted.
562 drm_gem_open_ioctl(struct drm_device *dev, void *data,
563 struct drm_file *file_priv)
565 struct drm_gem_open *args = data;
566 struct drm_gem_object *obj;
570 if (!(dev->driver->driver_features & DRIVER_GEM))
573 mutex_lock(&dev->object_name_lock);
574 obj = idr_find(&dev->object_name_idr, (int) args->name);
576 drm_gem_object_reference(obj);
578 mutex_unlock(&dev->object_name_lock);
582 /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */
583 ret = drm_gem_handle_create_tail(file_priv, obj, &handle);
584 drm_gem_object_unreference_unlocked(obj);
588 args->handle = handle;
589 args->size = obj->size;
591 DRM_DEBUG("%s:name[%d]obj[0x%x]hdl[%d]sz[%d]\n",
592 __func__, (int) args->name, (int)obj,
593 args->handle, (int)args->size);
599 * Called at device open time, sets up the structure for handling refcounting
603 drm_gem_open(struct drm_device *dev, struct drm_file *file_private)
605 idr_init(&file_private->object_idr);
606 spin_lock_init(&file_private->table_lock);
610 * Called at device close to release the file's
611 * handle references on objects.
614 drm_gem_object_release_handle(int id, void *ptr, void *data)
616 struct drm_file *file_priv = data;
617 struct drm_gem_object *obj = ptr;
618 struct drm_device *dev = obj->dev;
620 drm_gem_remove_prime_handles(obj, file_priv);
622 if (dev->driver->gem_close_object)
623 dev->driver->gem_close_object(obj, file_priv);
625 drm_gem_object_handle_unreference_unlocked(obj);
631 * Called at close time when the filp is going away.
633 * Releases any remaining references on objects by this filp.
636 drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
638 idr_for_each(&file_private->object_idr,
639 &drm_gem_object_release_handle, file_private);
640 idr_destroy(&file_private->object_idr);
644 drm_gem_object_release(struct drm_gem_object *obj)
649 EXPORT_SYMBOL(drm_gem_object_release);
652 * Called after the last reference to the object has been lost.
653 * Must be called holding struct_ mutex
658 drm_gem_object_free(struct kref *kref)
660 struct drm_gem_object *obj = (struct drm_gem_object *) kref;
661 struct drm_device *dev = obj->dev;
663 BUG_ON(!mutex_is_locked(&dev->struct_mutex));
665 if (dev->driver->gem_free_object != NULL)
666 dev->driver->gem_free_object(obj);
668 EXPORT_SYMBOL(drm_gem_object_free);
670 void drm_gem_vm_open(struct vm_area_struct *vma)
672 struct drm_gem_object *obj = vma->vm_private_data;
674 drm_gem_object_reference(obj);
676 mutex_lock(&obj->dev->struct_mutex);
677 drm_vm_open_locked(obj->dev, vma);
678 mutex_unlock(&obj->dev->struct_mutex);
680 EXPORT_SYMBOL(drm_gem_vm_open);
682 void drm_gem_vm_close(struct vm_area_struct *vma)
684 struct drm_gem_object *obj = vma->vm_private_data;
685 struct drm_device *dev = obj->dev;
687 mutex_lock(&dev->struct_mutex);
688 drm_vm_close_locked(obj->dev, vma);
689 drm_gem_object_unreference(obj);
690 mutex_unlock(&dev->struct_mutex);
692 EXPORT_SYMBOL(drm_gem_vm_close);
695 * drm_gem_mmap_obj - memory map a GEM object
696 * @obj: the GEM object to map
697 * @obj_size: the object size to be mapped, in bytes
698 * @vma: VMA for the area to be mapped
700 * Set up the VMA to prepare mapping of the GEM object using the gem_vm_ops
701 * provided by the driver. Depending on their requirements, drivers can either
702 * provide a fault handler in their gem_vm_ops (in which case any accesses to
703 * the object will be trapped, to perform migration, GTT binding, surface
704 * register allocation, or performance monitoring), or mmap the buffer memory
705 * synchronously after calling drm_gem_mmap_obj.
707 * This function is mainly intended to implement the DMABUF mmap operation, when
708 * the GEM object is not looked up based on its fake offset. To implement the
709 * DRM mmap operation, drivers should use the drm_gem_mmap() function.
711 * NOTE: This function has to be protected with dev->struct_mutex
713 * Return 0 or success or -EINVAL if the object size is smaller than the VMA
714 * size, or if no gem_vm_ops are provided.
716 int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
717 struct vm_area_struct *vma)
719 struct drm_device *dev = obj->dev;
721 lockdep_assert_held(&dev->struct_mutex);
723 /* Check for valid size. */
724 if (obj_size < vma->vm_end - vma->vm_start)
727 if (!dev->driver->gem_vm_ops)
730 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
731 vma->vm_ops = dev->driver->gem_vm_ops;
732 vma->vm_private_data = obj;
733 vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
735 /* Take a ref for this mapping of the object, so that the fault
736 * handler can dereference the mmap offset's pointer to the object.
737 * This reference is cleaned up by the corresponding vm_close
738 * (which should happen whether the vma was created by this call, or
739 * by a vm_open due to mremap or partial unmap or whatever).
741 drm_gem_object_reference(obj);
743 drm_vm_open_locked(dev, vma);
746 EXPORT_SYMBOL(drm_gem_mmap_obj);
749 * drm_gem_mmap - memory map routine for GEM objects
750 * @filp: DRM file pointer
751 * @vma: VMA for the area to be mapped
753 * If a driver supports GEM object mapping, mmap calls on the DRM file
754 * descriptor will end up here.
756 * Look up the GEM object based on the offset passed in (vma->vm_pgoff will
757 * contain the fake offset we created when the GTT map ioctl was called on
758 * the object) and map it with a call to drm_gem_mmap_obj().
760 int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
762 struct drm_file *priv = filp->private_data;
763 struct drm_device *dev = priv->minor->dev;
764 struct drm_gem_mm *mm = dev->mm_private;
765 struct drm_local_map *map = NULL;
766 struct drm_hash_item *hash;
769 if (drm_device_is_unplugged(dev))
772 mutex_lock(&dev->struct_mutex);
774 if (drm_ht_find_item(&mm->offset_hash, vma->vm_pgoff, &hash)) {
775 mutex_unlock(&dev->struct_mutex);
776 return drm_mmap(filp, vma);
779 map = drm_hash_entry(hash, struct drm_map_list, hash)->map;
781 ((map->flags & _DRM_RESTRICTED) && !capable(CAP_SYS_ADMIN))) {
786 ret = drm_gem_mmap_obj(map->handle, map->size, vma);
789 mutex_unlock(&dev->struct_mutex);
793 EXPORT_SYMBOL(drm_gem_mmap);