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>
40 #include <drm/drm_vma_manager.h>
44 * This file provides some of the base ioctls and library routines for
45 * the graphics memory manager implemented by each device driver.
47 * Because various devices have different requirements in terms of
48 * synchronization and migration strategies, implementing that is left up to
49 * the driver, and all that the general API provides should be generic --
50 * allocating objects, reading/writing data with the cpu, freeing objects.
51 * Even there, platform-dependent optimizations for reading/writing data with
52 * the CPU mean we'll likely hook those out to driver-specific calls. However,
53 * the DRI2 implementation wants to have at least allocate/mmap be generic.
55 * The goal was to have swap-backed object allocation managed through
56 * struct file. However, file descriptors as handles to a struct file have
58 * - Process limits prevent more than 1024 or so being used at a time by
60 * - Inability to allocate high fds will aggravate the X Server's select()
61 * handling, and likely that of many GL client applications as well.
63 * This led to a plan of using our own integer IDs (called handles, following
64 * DRM terminology) to mimic fds, and implement the fd syscalls we need as
65 * ioctls. The objects themselves will still include the struct file so
66 * that we can transition to fds if the required kernel infrastructure shows
67 * up at a later date, and as our interface with shmfs for memory allocation.
71 * We make up offsets for buffer objects so we can recognize them at
75 /* pgoff in mmap is an unsigned long, so we need to make sure that
76 * the faked up offset will fit
79 #if BITS_PER_LONG == 64
80 #define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFFUL >> PAGE_SHIFT) + 1)
81 #define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFFUL >> PAGE_SHIFT) * 16)
83 #define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFUL >> PAGE_SHIFT) + 1)
84 #define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFUL >> PAGE_SHIFT) * 16)
88 * Initialize the GEM device fields
92 drm_gem_init(struct drm_device *dev)
94 struct drm_gem_mm *mm;
96 spin_lock_init(&dev->object_name_lock);
97 idr_init(&dev->object_name_idr);
99 mm = kzalloc(sizeof(struct drm_gem_mm), GFP_KERNEL);
101 DRM_ERROR("out of memory\n");
105 dev->mm_private = mm;
106 drm_vma_offset_manager_init(&mm->vma_manager,
107 DRM_FILE_PAGE_OFFSET_START,
108 DRM_FILE_PAGE_OFFSET_SIZE);
114 drm_gem_destroy(struct drm_device *dev)
116 struct drm_gem_mm *mm = dev->mm_private;
118 drm_vma_offset_manager_destroy(&mm->vma_manager);
120 dev->mm_private = NULL;
124 * Initialize an already allocated GEM object of the specified size with
125 * shmfs backing store.
127 int drm_gem_object_init(struct drm_device *dev,
128 struct drm_gem_object *obj, size_t size)
132 filp = shmem_file_setup("drm mm object", size, VM_NORESERVE);
134 return PTR_ERR(filp);
136 drm_gem_private_object_init(dev, obj, size);
141 EXPORT_SYMBOL(drm_gem_object_init);
144 * Initialize an already allocated GEM object of the specified size with
145 * no GEM provided backing store. Instead the caller is responsible for
146 * backing the object and handling it.
148 void drm_gem_private_object_init(struct drm_device *dev,
149 struct drm_gem_object *obj, size_t size)
151 BUG_ON((size & (PAGE_SIZE - 1)) != 0);
156 kref_init(&obj->refcount);
157 atomic_set(&obj->handle_count, 0);
160 EXPORT_SYMBOL(drm_gem_private_object_init);
163 * Allocate a GEM object of the specified size with shmfs backing store
165 struct drm_gem_object *
166 drm_gem_object_alloc(struct drm_device *dev, size_t size)
168 struct drm_gem_object *obj;
170 obj = kzalloc(sizeof(*obj), GFP_KERNEL);
174 if (drm_gem_object_init(dev, obj, size) != 0)
177 if (dev->driver->gem_init_object != NULL &&
178 dev->driver->gem_init_object(obj) != 0) {
183 /* Object_init mangles the global counters - readjust them. */
189 EXPORT_SYMBOL(drm_gem_object_alloc);
192 drm_gem_remove_prime_handles(struct drm_gem_object *obj, struct drm_file *filp)
194 if (obj->import_attach) {
195 drm_prime_remove_buf_handle(&filp->prime,
196 obj->import_attach->dmabuf);
198 if (obj->export_dma_buf) {
199 drm_prime_remove_buf_handle(&filp->prime,
200 obj->export_dma_buf);
205 * Removes the mapping from handle to filp for this object.
208 drm_gem_handle_delete(struct drm_file *filp, u32 handle)
210 struct drm_device *dev;
211 struct drm_gem_object *obj;
213 /* This is gross. The idr system doesn't let us try a delete and
214 * return an error code. It just spews if you fail at deleting.
215 * So, we have to grab a lock around finding the object and then
216 * doing the delete on it and dropping the refcount, or the user
217 * could race us to double-decrement the refcount and cause a
218 * use-after-free later. Given the frequency of our handle lookups,
219 * we may want to use ida for number allocation and a hash table
220 * for the pointers, anyway.
222 spin_lock(&filp->table_lock);
224 /* Check if we currently have a reference on the object */
225 obj = idr_find(&filp->object_idr, handle);
227 spin_unlock(&filp->table_lock);
232 /* Release reference and decrement refcount. */
233 idr_remove(&filp->object_idr, handle);
234 spin_unlock(&filp->table_lock);
236 drm_gem_remove_prime_handles(obj, filp);
238 if (dev->driver->gem_close_object)
239 dev->driver->gem_close_object(obj, filp);
240 drm_gem_object_handle_unreference_unlocked(obj);
244 EXPORT_SYMBOL(drm_gem_handle_delete);
247 * drm_gem_dumb_destroy - dumb fb callback helper for gem based drivers
249 * This implements the ->dumb_destroy kms driver callback for drivers which use
250 * gem to manage their backing storage.
252 int drm_gem_dumb_destroy(struct drm_file *file,
253 struct drm_device *dev,
256 return drm_gem_handle_delete(file, handle);
258 EXPORT_SYMBOL(drm_gem_dumb_destroy);
261 * Create a handle for this object. This adds a handle reference
262 * to the object, which includes a regular reference count. Callers
263 * will likely want to dereference the object afterwards.
266 drm_gem_handle_create(struct drm_file *file_priv,
267 struct drm_gem_object *obj,
270 struct drm_device *dev = obj->dev;
274 * Get the user-visible handle using idr. Preload and perform
275 * allocation under our spinlock.
277 idr_preload(GFP_KERNEL);
278 spin_lock(&file_priv->table_lock);
280 ret = idr_alloc(&file_priv->object_idr, obj, 1, 0, GFP_NOWAIT);
282 spin_unlock(&file_priv->table_lock);
288 drm_gem_object_handle_reference(obj);
290 if (dev->driver->gem_open_object) {
291 ret = dev->driver->gem_open_object(obj, file_priv);
293 drm_gem_handle_delete(file_priv, *handlep);
300 EXPORT_SYMBOL(drm_gem_handle_create);
304 * drm_gem_free_mmap_offset - release a fake mmap offset for an object
305 * @obj: obj in question
307 * This routine frees fake offsets allocated by drm_gem_create_mmap_offset().
310 drm_gem_free_mmap_offset(struct drm_gem_object *obj)
312 struct drm_device *dev = obj->dev;
313 struct drm_gem_mm *mm = dev->mm_private;
315 drm_vma_offset_remove(&mm->vma_manager, &obj->vma_node);
317 EXPORT_SYMBOL(drm_gem_free_mmap_offset);
320 * drm_gem_create_mmap_offset - create a fake mmap offset for an object
321 * @obj: obj in question
323 * GEM memory mapping works by handing back to userspace a fake mmap offset
324 * it can use in a subsequent mmap(2) call. The DRM core code then looks
325 * up the object based on the offset and sets up the various memory mapping
328 * This routine allocates and attaches a fake offset for @obj.
331 drm_gem_create_mmap_offset(struct drm_gem_object *obj)
333 struct drm_device *dev = obj->dev;
334 struct drm_gem_mm *mm = dev->mm_private;
336 return drm_vma_offset_add(&mm->vma_manager, &obj->vma_node,
337 obj->size / PAGE_SIZE);
339 EXPORT_SYMBOL(drm_gem_create_mmap_offset);
341 /** Returns a reference to the object named by the handle. */
342 struct drm_gem_object *
343 drm_gem_object_lookup(struct drm_device *dev, struct drm_file *filp,
346 struct drm_gem_object *obj;
348 spin_lock(&filp->table_lock);
350 /* Check if we currently have a reference on the object */
351 obj = idr_find(&filp->object_idr, handle);
353 spin_unlock(&filp->table_lock);
357 drm_gem_object_reference(obj);
359 spin_unlock(&filp->table_lock);
363 EXPORT_SYMBOL(drm_gem_object_lookup);
366 * Releases the handle to an mm object.
369 drm_gem_close_ioctl(struct drm_device *dev, void *data,
370 struct drm_file *file_priv)
372 struct drm_gem_close *args = data;
375 if (!(dev->driver->driver_features & DRIVER_GEM))
378 ret = drm_gem_handle_delete(file_priv, args->handle);
384 * Create a global name for an object, returning the name.
386 * Note that the name does not hold a reference; when the object
387 * is freed, the name goes away.
390 drm_gem_flink_ioctl(struct drm_device *dev, void *data,
391 struct drm_file *file_priv)
393 struct drm_gem_flink *args = data;
394 struct drm_gem_object *obj;
397 if (!(dev->driver->driver_features & DRIVER_GEM))
400 obj = drm_gem_object_lookup(dev, file_priv, args->handle);
404 idr_preload(GFP_KERNEL);
405 spin_lock(&dev->object_name_lock);
407 ret = idr_alloc(&dev->object_name_idr, obj, 1, 0, GFP_NOWAIT);
413 /* Allocate a reference for the name table. */
414 drm_gem_object_reference(obj);
417 args->name = (uint64_t) obj->name;
421 spin_unlock(&dev->object_name_lock);
423 drm_gem_object_unreference_unlocked(obj);
428 * Open an object using the global name, returning a handle and the size.
430 * This handle (of course) holds a reference to the object, so the object
431 * will not go away until the handle is deleted.
434 drm_gem_open_ioctl(struct drm_device *dev, void *data,
435 struct drm_file *file_priv)
437 struct drm_gem_open *args = data;
438 struct drm_gem_object *obj;
442 if (!(dev->driver->driver_features & DRIVER_GEM))
445 spin_lock(&dev->object_name_lock);
446 obj = idr_find(&dev->object_name_idr, (int) args->name);
448 drm_gem_object_reference(obj);
449 spin_unlock(&dev->object_name_lock);
453 ret = drm_gem_handle_create(file_priv, obj, &handle);
454 drm_gem_object_unreference_unlocked(obj);
458 args->handle = handle;
459 args->size = obj->size;
465 * Called at device open time, sets up the structure for handling refcounting
469 drm_gem_open(struct drm_device *dev, struct drm_file *file_private)
471 idr_init(&file_private->object_idr);
472 spin_lock_init(&file_private->table_lock);
476 * Called at device close to release the file's
477 * handle references on objects.
480 drm_gem_object_release_handle(int id, void *ptr, void *data)
482 struct drm_file *file_priv = data;
483 struct drm_gem_object *obj = ptr;
484 struct drm_device *dev = obj->dev;
486 drm_gem_remove_prime_handles(obj, file_priv);
488 if (dev->driver->gem_close_object)
489 dev->driver->gem_close_object(obj, file_priv);
491 drm_gem_object_handle_unreference_unlocked(obj);
497 * Called at close time when the filp is going away.
499 * Releases any remaining references on objects by this filp.
502 drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
504 idr_for_each(&file_private->object_idr,
505 &drm_gem_object_release_handle, file_private);
506 idr_destroy(&file_private->object_idr);
510 drm_gem_object_release(struct drm_gem_object *obj)
515 EXPORT_SYMBOL(drm_gem_object_release);
518 * Called after the last reference to the object has been lost.
519 * Must be called holding struct_ mutex
524 drm_gem_object_free(struct kref *kref)
526 struct drm_gem_object *obj = (struct drm_gem_object *) kref;
527 struct drm_device *dev = obj->dev;
529 BUG_ON(!mutex_is_locked(&dev->struct_mutex));
531 if (dev->driver->gem_free_object != NULL)
532 dev->driver->gem_free_object(obj);
534 EXPORT_SYMBOL(drm_gem_object_free);
536 static void drm_gem_object_ref_bug(struct kref *list_kref)
542 * Called after the last handle to the object has been closed
544 * Removes any name for the object. Note that this must be
545 * called before drm_gem_object_free or we'll be touching
548 void drm_gem_object_handle_free(struct drm_gem_object *obj)
550 struct drm_device *dev = obj->dev;
552 /* Remove any name for this object */
553 spin_lock(&dev->object_name_lock);
555 idr_remove(&dev->object_name_idr, obj->name);
557 spin_unlock(&dev->object_name_lock);
559 * The object name held a reference to this object, drop
562 * This cannot be the last reference, since the handle holds one too.
564 kref_put(&obj->refcount, drm_gem_object_ref_bug);
566 spin_unlock(&dev->object_name_lock);
569 EXPORT_SYMBOL(drm_gem_object_handle_free);
571 void drm_gem_vm_open(struct vm_area_struct *vma)
573 struct drm_gem_object *obj = vma->vm_private_data;
575 drm_gem_object_reference(obj);
577 mutex_lock(&obj->dev->struct_mutex);
578 drm_vm_open_locked(obj->dev, vma);
579 mutex_unlock(&obj->dev->struct_mutex);
581 EXPORT_SYMBOL(drm_gem_vm_open);
583 void drm_gem_vm_close(struct vm_area_struct *vma)
585 struct drm_gem_object *obj = vma->vm_private_data;
586 struct drm_device *dev = obj->dev;
588 mutex_lock(&dev->struct_mutex);
589 drm_vm_close_locked(obj->dev, vma);
590 drm_gem_object_unreference(obj);
591 mutex_unlock(&dev->struct_mutex);
593 EXPORT_SYMBOL(drm_gem_vm_close);
596 * drm_gem_mmap_obj - memory map a GEM object
597 * @obj: the GEM object to map
598 * @obj_size: the object size to be mapped, in bytes
599 * @vma: VMA for the area to be mapped
601 * Set up the VMA to prepare mapping of the GEM object using the gem_vm_ops
602 * provided by the driver. Depending on their requirements, drivers can either
603 * provide a fault handler in their gem_vm_ops (in which case any accesses to
604 * the object will be trapped, to perform migration, GTT binding, surface
605 * register allocation, or performance monitoring), or mmap the buffer memory
606 * synchronously after calling drm_gem_mmap_obj.
608 * This function is mainly intended to implement the DMABUF mmap operation, when
609 * the GEM object is not looked up based on its fake offset. To implement the
610 * DRM mmap operation, drivers should use the drm_gem_mmap() function.
612 * NOTE: This function has to be protected with dev->struct_mutex
614 * Return 0 or success or -EINVAL if the object size is smaller than the VMA
615 * size, or if no gem_vm_ops are provided.
617 int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
618 struct vm_area_struct *vma)
620 struct drm_device *dev = obj->dev;
622 lockdep_assert_held(&dev->struct_mutex);
624 /* Check for valid size. */
625 if (obj_size < vma->vm_end - vma->vm_start)
628 if (!dev->driver->gem_vm_ops)
631 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
632 vma->vm_ops = dev->driver->gem_vm_ops;
633 vma->vm_private_data = obj;
634 vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
636 /* Take a ref for this mapping of the object, so that the fault
637 * handler can dereference the mmap offset's pointer to the object.
638 * This reference is cleaned up by the corresponding vm_close
639 * (which should happen whether the vma was created by this call, or
640 * by a vm_open due to mremap or partial unmap or whatever).
642 drm_gem_object_reference(obj);
644 drm_vm_open_locked(dev, vma);
647 EXPORT_SYMBOL(drm_gem_mmap_obj);
650 * drm_gem_mmap - memory map routine for GEM objects
651 * @filp: DRM file pointer
652 * @vma: VMA for the area to be mapped
654 * If a driver supports GEM object mapping, mmap calls on the DRM file
655 * descriptor will end up here.
657 * Look up the GEM object based on the offset passed in (vma->vm_pgoff will
658 * contain the fake offset we created when the GTT map ioctl was called on
659 * the object) and map it with a call to drm_gem_mmap_obj().
661 int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
663 struct drm_file *priv = filp->private_data;
664 struct drm_device *dev = priv->minor->dev;
665 struct drm_gem_mm *mm = dev->mm_private;
666 struct drm_gem_object *obj;
667 struct drm_vma_offset_node *node;
670 if (drm_device_is_unplugged(dev))
673 mutex_lock(&dev->struct_mutex);
675 node = drm_vma_offset_exact_lookup(&mm->vma_manager, vma->vm_pgoff,
678 mutex_unlock(&dev->struct_mutex);
679 return drm_mmap(filp, vma);
682 obj = container_of(node, struct drm_gem_object, vma_node);
683 ret = drm_gem_mmap_obj(obj, drm_vma_node_size(node) << PAGE_SHIFT, vma);
685 mutex_unlock(&dev->struct_mutex);
689 EXPORT_SYMBOL(drm_gem_mmap);