xref: /openbmc/linux/drivers/gpu/drm/drm_gem.c (revision 6aa7de05)
1 /*
2  * Copyright © 2008 Intel Corporation
3  *
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:
10  *
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
13  * Software.
14  *
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
21  * IN THE SOFTWARE.
22  *
23  * Authors:
24  *    Eric Anholt <eric@anholt.net>
25  *
26  */
27 
28 #include <linux/types.h>
29 #include <linux/slab.h>
30 #include <linux/mm.h>
31 #include <linux/uaccess.h>
32 #include <linux/fs.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>
39 #include <linux/mem_encrypt.h>
40 #include <drm/drmP.h>
41 #include <drm/drm_vma_manager.h>
42 #include <drm/drm_gem.h>
43 #include "drm_internal.h"
44 
45 /** @file drm_gem.c
46  *
47  * This file provides some of the base ioctls and library routines for
48  * the graphics memory manager implemented by each device driver.
49  *
50  * Because various devices have different requirements in terms of
51  * synchronization and migration strategies, implementing that is left up to
52  * the driver, and all that the general API provides should be generic --
53  * allocating objects, reading/writing data with the cpu, freeing objects.
54  * Even there, platform-dependent optimizations for reading/writing data with
55  * the CPU mean we'll likely hook those out to driver-specific calls.  However,
56  * the DRI2 implementation wants to have at least allocate/mmap be generic.
57  *
58  * The goal was to have swap-backed object allocation managed through
59  * struct file.  However, file descriptors as handles to a struct file have
60  * two major failings:
61  * - Process limits prevent more than 1024 or so being used at a time by
62  *   default.
63  * - Inability to allocate high fds will aggravate the X Server's select()
64  *   handling, and likely that of many GL client applications as well.
65  *
66  * This led to a plan of using our own integer IDs (called handles, following
67  * DRM terminology) to mimic fds, and implement the fd syscalls we need as
68  * ioctls.  The objects themselves will still include the struct file so
69  * that we can transition to fds if the required kernel infrastructure shows
70  * up at a later date, and as our interface with shmfs for memory allocation.
71  */
72 
73 /*
74  * We make up offsets for buffer objects so we can recognize them at
75  * mmap time.
76  */
77 
78 /* pgoff in mmap is an unsigned long, so we need to make sure that
79  * the faked up offset will fit
80  */
81 
82 #if BITS_PER_LONG == 64
83 #define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFFUL >> PAGE_SHIFT) + 1)
84 #define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFFUL >> PAGE_SHIFT) * 16)
85 #else
86 #define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFUL >> PAGE_SHIFT) + 1)
87 #define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFUL >> PAGE_SHIFT) * 16)
88 #endif
89 
90 /**
91  * drm_gem_init - Initialize the GEM device fields
92  * @dev: drm_devic structure to initialize
93  */
94 int
95 drm_gem_init(struct drm_device *dev)
96 {
97 	struct drm_vma_offset_manager *vma_offset_manager;
98 
99 	mutex_init(&dev->object_name_lock);
100 	idr_init(&dev->object_name_idr);
101 
102 	vma_offset_manager = kzalloc(sizeof(*vma_offset_manager), GFP_KERNEL);
103 	if (!vma_offset_manager) {
104 		DRM_ERROR("out of memory\n");
105 		return -ENOMEM;
106 	}
107 
108 	dev->vma_offset_manager = vma_offset_manager;
109 	drm_vma_offset_manager_init(vma_offset_manager,
110 				    DRM_FILE_PAGE_OFFSET_START,
111 				    DRM_FILE_PAGE_OFFSET_SIZE);
112 
113 	return 0;
114 }
115 
116 void
117 drm_gem_destroy(struct drm_device *dev)
118 {
119 
120 	drm_vma_offset_manager_destroy(dev->vma_offset_manager);
121 	kfree(dev->vma_offset_manager);
122 	dev->vma_offset_manager = NULL;
123 }
124 
125 /**
126  * drm_gem_object_init - initialize an allocated shmem-backed GEM object
127  * @dev: drm_device the object should be initialized for
128  * @obj: drm_gem_object to initialize
129  * @size: object size
130  *
131  * Initialize an already allocated GEM object of the specified size with
132  * shmfs backing store.
133  */
134 int drm_gem_object_init(struct drm_device *dev,
135 			struct drm_gem_object *obj, size_t size)
136 {
137 	struct file *filp;
138 
139 	drm_gem_private_object_init(dev, obj, size);
140 
141 	filp = shmem_file_setup("drm mm object", size, VM_NORESERVE);
142 	if (IS_ERR(filp))
143 		return PTR_ERR(filp);
144 
145 	obj->filp = filp;
146 
147 	return 0;
148 }
149 EXPORT_SYMBOL(drm_gem_object_init);
150 
151 /**
152  * drm_gem_private_object_init - initialize an allocated private GEM object
153  * @dev: drm_device the object should be initialized for
154  * @obj: drm_gem_object to initialize
155  * @size: object size
156  *
157  * Initialize an already allocated GEM object of the specified size with
158  * no GEM provided backing store. Instead the caller is responsible for
159  * backing the object and handling it.
160  */
161 void drm_gem_private_object_init(struct drm_device *dev,
162 				 struct drm_gem_object *obj, size_t size)
163 {
164 	BUG_ON((size & (PAGE_SIZE - 1)) != 0);
165 
166 	obj->dev = dev;
167 	obj->filp = NULL;
168 
169 	kref_init(&obj->refcount);
170 	obj->handle_count = 0;
171 	obj->size = size;
172 	drm_vma_node_reset(&obj->vma_node);
173 }
174 EXPORT_SYMBOL(drm_gem_private_object_init);
175 
176 static void
177 drm_gem_remove_prime_handles(struct drm_gem_object *obj, struct drm_file *filp)
178 {
179 	/*
180 	 * Note: obj->dma_buf can't disappear as long as we still hold a
181 	 * handle reference in obj->handle_count.
182 	 */
183 	mutex_lock(&filp->prime.lock);
184 	if (obj->dma_buf) {
185 		drm_prime_remove_buf_handle_locked(&filp->prime,
186 						   obj->dma_buf);
187 	}
188 	mutex_unlock(&filp->prime.lock);
189 }
190 
191 /**
192  * drm_gem_object_handle_free - release resources bound to userspace handles
193  * @obj: GEM object to clean up.
194  *
195  * Called after the last handle to the object has been closed
196  *
197  * Removes any name for the object. Note that this must be
198  * called before drm_gem_object_free or we'll be touching
199  * freed memory
200  */
201 static void drm_gem_object_handle_free(struct drm_gem_object *obj)
202 {
203 	struct drm_device *dev = obj->dev;
204 
205 	/* Remove any name for this object */
206 	if (obj->name) {
207 		idr_remove(&dev->object_name_idr, obj->name);
208 		obj->name = 0;
209 	}
210 }
211 
212 static void drm_gem_object_exported_dma_buf_free(struct drm_gem_object *obj)
213 {
214 	/* Unbreak the reference cycle if we have an exported dma_buf. */
215 	if (obj->dma_buf) {
216 		dma_buf_put(obj->dma_buf);
217 		obj->dma_buf = NULL;
218 	}
219 }
220 
221 static void
222 drm_gem_object_handle_put_unlocked(struct drm_gem_object *obj)
223 {
224 	struct drm_device *dev = obj->dev;
225 	bool final = false;
226 
227 	if (WARN_ON(obj->handle_count == 0))
228 		return;
229 
230 	/*
231 	* Must bump handle count first as this may be the last
232 	* ref, in which case the object would disappear before we
233 	* checked for a name
234 	*/
235 
236 	mutex_lock(&dev->object_name_lock);
237 	if (--obj->handle_count == 0) {
238 		drm_gem_object_handle_free(obj);
239 		drm_gem_object_exported_dma_buf_free(obj);
240 		final = true;
241 	}
242 	mutex_unlock(&dev->object_name_lock);
243 
244 	if (final)
245 		drm_gem_object_put_unlocked(obj);
246 }
247 
248 /*
249  * Called at device or object close to release the file's
250  * handle references on objects.
251  */
252 static int
253 drm_gem_object_release_handle(int id, void *ptr, void *data)
254 {
255 	struct drm_file *file_priv = data;
256 	struct drm_gem_object *obj = ptr;
257 	struct drm_device *dev = obj->dev;
258 
259 	if (dev->driver->gem_close_object)
260 		dev->driver->gem_close_object(obj, file_priv);
261 
262 	if (drm_core_check_feature(dev, DRIVER_PRIME))
263 		drm_gem_remove_prime_handles(obj, file_priv);
264 	drm_vma_node_revoke(&obj->vma_node, file_priv);
265 
266 	drm_gem_object_handle_put_unlocked(obj);
267 
268 	return 0;
269 }
270 
271 /**
272  * drm_gem_handle_delete - deletes the given file-private handle
273  * @filp: drm file-private structure to use for the handle look up
274  * @handle: userspace handle to delete
275  *
276  * Removes the GEM handle from the @filp lookup table which has been added with
277  * drm_gem_handle_create(). If this is the last handle also cleans up linked
278  * resources like GEM names.
279  */
280 int
281 drm_gem_handle_delete(struct drm_file *filp, u32 handle)
282 {
283 	struct drm_gem_object *obj;
284 
285 	/* This is gross. The idr system doesn't let us try a delete and
286 	 * return an error code.  It just spews if you fail at deleting.
287 	 * So, we have to grab a lock around finding the object and then
288 	 * doing the delete on it and dropping the refcount, or the user
289 	 * could race us to double-decrement the refcount and cause a
290 	 * use-after-free later.  Given the frequency of our handle lookups,
291 	 * we may want to use ida for number allocation and a hash table
292 	 * for the pointers, anyway.
293 	 */
294 	spin_lock(&filp->table_lock);
295 
296 	/* Check if we currently have a reference on the object */
297 	obj = idr_replace(&filp->object_idr, NULL, handle);
298 	spin_unlock(&filp->table_lock);
299 	if (IS_ERR_OR_NULL(obj))
300 		return -EINVAL;
301 
302 	/* Release driver's reference and decrement refcount. */
303 	drm_gem_object_release_handle(handle, obj, filp);
304 
305 	/* And finally make the handle available for future allocations. */
306 	spin_lock(&filp->table_lock);
307 	idr_remove(&filp->object_idr, handle);
308 	spin_unlock(&filp->table_lock);
309 
310 	return 0;
311 }
312 EXPORT_SYMBOL(drm_gem_handle_delete);
313 
314 /**
315  * drm_gem_dumb_map_offset - return the fake mmap offset for a gem object
316  * @file: drm file-private structure containing the gem object
317  * @dev: corresponding drm_device
318  * @handle: gem object handle
319  * @offset: return location for the fake mmap offset
320  *
321  * This implements the &drm_driver.dumb_map_offset kms driver callback for
322  * drivers which use gem to manage their backing storage.
323  *
324  * Returns:
325  * 0 on success or a negative error code on failure.
326  */
327 int drm_gem_dumb_map_offset(struct drm_file *file, struct drm_device *dev,
328 			    u32 handle, u64 *offset)
329 {
330 	struct drm_gem_object *obj;
331 	int ret;
332 
333 	obj = drm_gem_object_lookup(file, handle);
334 	if (!obj)
335 		return -ENOENT;
336 
337 	ret = drm_gem_create_mmap_offset(obj);
338 	if (ret)
339 		goto out;
340 
341 	*offset = drm_vma_node_offset_addr(&obj->vma_node);
342 out:
343 	drm_gem_object_put_unlocked(obj);
344 
345 	return ret;
346 }
347 EXPORT_SYMBOL_GPL(drm_gem_dumb_map_offset);
348 
349 /**
350  * drm_gem_dumb_destroy - dumb fb callback helper for gem based drivers
351  * @file: drm file-private structure to remove the dumb handle from
352  * @dev: corresponding drm_device
353  * @handle: the dumb handle to remove
354  *
355  * This implements the &drm_driver.dumb_destroy kms driver callback for drivers
356  * which use gem to manage their backing storage.
357  */
358 int drm_gem_dumb_destroy(struct drm_file *file,
359 			 struct drm_device *dev,
360 			 uint32_t handle)
361 {
362 	return drm_gem_handle_delete(file, handle);
363 }
364 EXPORT_SYMBOL(drm_gem_dumb_destroy);
365 
366 /**
367  * drm_gem_handle_create_tail - internal functions to create a handle
368  * @file_priv: drm file-private structure to register the handle for
369  * @obj: object to register
370  * @handlep: pointer to return the created handle to the caller
371  *
372  * This expects the &drm_device.object_name_lock to be held already and will
373  * drop it before returning. Used to avoid races in establishing new handles
374  * when importing an object from either an flink name or a dma-buf.
375  *
376  * Handles must be release again through drm_gem_handle_delete(). This is done
377  * when userspace closes @file_priv for all attached handles, or through the
378  * GEM_CLOSE ioctl for individual handles.
379  */
380 int
381 drm_gem_handle_create_tail(struct drm_file *file_priv,
382 			   struct drm_gem_object *obj,
383 			   u32 *handlep)
384 {
385 	struct drm_device *dev = obj->dev;
386 	u32 handle;
387 	int ret;
388 
389 	WARN_ON(!mutex_is_locked(&dev->object_name_lock));
390 	if (obj->handle_count++ == 0)
391 		drm_gem_object_get(obj);
392 
393 	/*
394 	 * Get the user-visible handle using idr.  Preload and perform
395 	 * allocation under our spinlock.
396 	 */
397 	idr_preload(GFP_KERNEL);
398 	spin_lock(&file_priv->table_lock);
399 
400 	ret = idr_alloc(&file_priv->object_idr, obj, 1, 0, GFP_NOWAIT);
401 
402 	spin_unlock(&file_priv->table_lock);
403 	idr_preload_end();
404 
405 	mutex_unlock(&dev->object_name_lock);
406 	if (ret < 0)
407 		goto err_unref;
408 
409 	handle = ret;
410 
411 	ret = drm_vma_node_allow(&obj->vma_node, file_priv);
412 	if (ret)
413 		goto err_remove;
414 
415 	if (dev->driver->gem_open_object) {
416 		ret = dev->driver->gem_open_object(obj, file_priv);
417 		if (ret)
418 			goto err_revoke;
419 	}
420 
421 	*handlep = handle;
422 	return 0;
423 
424 err_revoke:
425 	drm_vma_node_revoke(&obj->vma_node, file_priv);
426 err_remove:
427 	spin_lock(&file_priv->table_lock);
428 	idr_remove(&file_priv->object_idr, handle);
429 	spin_unlock(&file_priv->table_lock);
430 err_unref:
431 	drm_gem_object_handle_put_unlocked(obj);
432 	return ret;
433 }
434 
435 /**
436  * drm_gem_handle_create - create a gem handle for an object
437  * @file_priv: drm file-private structure to register the handle for
438  * @obj: object to register
439  * @handlep: pionter to return the created handle to the caller
440  *
441  * Create a handle for this object. This adds a handle reference
442  * to the object, which includes a regular reference count. Callers
443  * will likely want to dereference the object afterwards.
444  */
445 int drm_gem_handle_create(struct drm_file *file_priv,
446 			  struct drm_gem_object *obj,
447 			  u32 *handlep)
448 {
449 	mutex_lock(&obj->dev->object_name_lock);
450 
451 	return drm_gem_handle_create_tail(file_priv, obj, handlep);
452 }
453 EXPORT_SYMBOL(drm_gem_handle_create);
454 
455 
456 /**
457  * drm_gem_free_mmap_offset - release a fake mmap offset for an object
458  * @obj: obj in question
459  *
460  * This routine frees fake offsets allocated by drm_gem_create_mmap_offset().
461  *
462  * Note that drm_gem_object_release() already calls this function, so drivers
463  * don't have to take care of releasing the mmap offset themselves when freeing
464  * the GEM object.
465  */
466 void
467 drm_gem_free_mmap_offset(struct drm_gem_object *obj)
468 {
469 	struct drm_device *dev = obj->dev;
470 
471 	drm_vma_offset_remove(dev->vma_offset_manager, &obj->vma_node);
472 }
473 EXPORT_SYMBOL(drm_gem_free_mmap_offset);
474 
475 /**
476  * drm_gem_create_mmap_offset_size - create a fake mmap offset for an object
477  * @obj: obj in question
478  * @size: the virtual size
479  *
480  * GEM memory mapping works by handing back to userspace a fake mmap offset
481  * it can use in a subsequent mmap(2) call.  The DRM core code then looks
482  * up the object based on the offset and sets up the various memory mapping
483  * structures.
484  *
485  * This routine allocates and attaches a fake offset for @obj, in cases where
486  * the virtual size differs from the physical size (ie. &drm_gem_object.size).
487  * Otherwise just use drm_gem_create_mmap_offset().
488  *
489  * This function is idempotent and handles an already allocated mmap offset
490  * transparently. Drivers do not need to check for this case.
491  */
492 int
493 drm_gem_create_mmap_offset_size(struct drm_gem_object *obj, size_t size)
494 {
495 	struct drm_device *dev = obj->dev;
496 
497 	return drm_vma_offset_add(dev->vma_offset_manager, &obj->vma_node,
498 				  size / PAGE_SIZE);
499 }
500 EXPORT_SYMBOL(drm_gem_create_mmap_offset_size);
501 
502 /**
503  * drm_gem_create_mmap_offset - create a fake mmap offset for an object
504  * @obj: obj in question
505  *
506  * GEM memory mapping works by handing back to userspace a fake mmap offset
507  * it can use in a subsequent mmap(2) call.  The DRM core code then looks
508  * up the object based on the offset and sets up the various memory mapping
509  * structures.
510  *
511  * This routine allocates and attaches a fake offset for @obj.
512  *
513  * Drivers can call drm_gem_free_mmap_offset() before freeing @obj to release
514  * the fake offset again.
515  */
516 int drm_gem_create_mmap_offset(struct drm_gem_object *obj)
517 {
518 	return drm_gem_create_mmap_offset_size(obj, obj->size);
519 }
520 EXPORT_SYMBOL(drm_gem_create_mmap_offset);
521 
522 /**
523  * drm_gem_get_pages - helper to allocate backing pages for a GEM object
524  * from shmem
525  * @obj: obj in question
526  *
527  * This reads the page-array of the shmem-backing storage of the given gem
528  * object. An array of pages is returned. If a page is not allocated or
529  * swapped-out, this will allocate/swap-in the required pages. Note that the
530  * whole object is covered by the page-array and pinned in memory.
531  *
532  * Use drm_gem_put_pages() to release the array and unpin all pages.
533  *
534  * This uses the GFP-mask set on the shmem-mapping (see mapping_set_gfp_mask()).
535  * If you require other GFP-masks, you have to do those allocations yourself.
536  *
537  * Note that you are not allowed to change gfp-zones during runtime. That is,
538  * shmem_read_mapping_page_gfp() must be called with the same gfp_zone(gfp) as
539  * set during initialization. If you have special zone constraints, set them
540  * after drm_gem_init_object() via mapping_set_gfp_mask(). shmem-core takes care
541  * to keep pages in the required zone during swap-in.
542  */
543 struct page **drm_gem_get_pages(struct drm_gem_object *obj)
544 {
545 	struct address_space *mapping;
546 	struct page *p, **pages;
547 	int i, npages;
548 
549 	/* This is the shared memory object that backs the GEM resource */
550 	mapping = obj->filp->f_mapping;
551 
552 	/* We already BUG_ON() for non-page-aligned sizes in
553 	 * drm_gem_object_init(), so we should never hit this unless
554 	 * driver author is doing something really wrong:
555 	 */
556 	WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0);
557 
558 	npages = obj->size >> PAGE_SHIFT;
559 
560 	pages = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
561 	if (pages == NULL)
562 		return ERR_PTR(-ENOMEM);
563 
564 	for (i = 0; i < npages; i++) {
565 		p = shmem_read_mapping_page(mapping, i);
566 		if (IS_ERR(p))
567 			goto fail;
568 		pages[i] = p;
569 
570 		/* Make sure shmem keeps __GFP_DMA32 allocated pages in the
571 		 * correct region during swapin. Note that this requires
572 		 * __GFP_DMA32 to be set in mapping_gfp_mask(inode->i_mapping)
573 		 * so shmem can relocate pages during swapin if required.
574 		 */
575 		BUG_ON(mapping_gfp_constraint(mapping, __GFP_DMA32) &&
576 				(page_to_pfn(p) >= 0x00100000UL));
577 	}
578 
579 	return pages;
580 
581 fail:
582 	while (i--)
583 		put_page(pages[i]);
584 
585 	kvfree(pages);
586 	return ERR_CAST(p);
587 }
588 EXPORT_SYMBOL(drm_gem_get_pages);
589 
590 /**
591  * drm_gem_put_pages - helper to free backing pages for a GEM object
592  * @obj: obj in question
593  * @pages: pages to free
594  * @dirty: if true, pages will be marked as dirty
595  * @accessed: if true, the pages will be marked as accessed
596  */
597 void drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages,
598 		bool dirty, bool accessed)
599 {
600 	int i, npages;
601 
602 	/* We already BUG_ON() for non-page-aligned sizes in
603 	 * drm_gem_object_init(), so we should never hit this unless
604 	 * driver author is doing something really wrong:
605 	 */
606 	WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0);
607 
608 	npages = obj->size >> PAGE_SHIFT;
609 
610 	for (i = 0; i < npages; i++) {
611 		if (dirty)
612 			set_page_dirty(pages[i]);
613 
614 		if (accessed)
615 			mark_page_accessed(pages[i]);
616 
617 		/* Undo the reference we took when populating the table */
618 		put_page(pages[i]);
619 	}
620 
621 	kvfree(pages);
622 }
623 EXPORT_SYMBOL(drm_gem_put_pages);
624 
625 /**
626  * drm_gem_object_lookup - look up a GEM object from it's handle
627  * @filp: DRM file private date
628  * @handle: userspace handle
629  *
630  * Returns:
631  *
632  * A reference to the object named by the handle if such exists on @filp, NULL
633  * otherwise.
634  */
635 struct drm_gem_object *
636 drm_gem_object_lookup(struct drm_file *filp, u32 handle)
637 {
638 	struct drm_gem_object *obj;
639 
640 	spin_lock(&filp->table_lock);
641 
642 	/* Check if we currently have a reference on the object */
643 	obj = idr_find(&filp->object_idr, handle);
644 	if (obj)
645 		drm_gem_object_get(obj);
646 
647 	spin_unlock(&filp->table_lock);
648 
649 	return obj;
650 }
651 EXPORT_SYMBOL(drm_gem_object_lookup);
652 
653 /**
654  * drm_gem_close_ioctl - implementation of the GEM_CLOSE ioctl
655  * @dev: drm_device
656  * @data: ioctl data
657  * @file_priv: drm file-private structure
658  *
659  * Releases the handle to an mm object.
660  */
661 int
662 drm_gem_close_ioctl(struct drm_device *dev, void *data,
663 		    struct drm_file *file_priv)
664 {
665 	struct drm_gem_close *args = data;
666 	int ret;
667 
668 	if (!drm_core_check_feature(dev, DRIVER_GEM))
669 		return -ENODEV;
670 
671 	ret = drm_gem_handle_delete(file_priv, args->handle);
672 
673 	return ret;
674 }
675 
676 /**
677  * drm_gem_flink_ioctl - implementation of the GEM_FLINK ioctl
678  * @dev: drm_device
679  * @data: ioctl data
680  * @file_priv: drm file-private structure
681  *
682  * Create a global name for an object, returning the name.
683  *
684  * Note that the name does not hold a reference; when the object
685  * is freed, the name goes away.
686  */
687 int
688 drm_gem_flink_ioctl(struct drm_device *dev, void *data,
689 		    struct drm_file *file_priv)
690 {
691 	struct drm_gem_flink *args = data;
692 	struct drm_gem_object *obj;
693 	int ret;
694 
695 	if (!drm_core_check_feature(dev, DRIVER_GEM))
696 		return -ENODEV;
697 
698 	obj = drm_gem_object_lookup(file_priv, args->handle);
699 	if (obj == NULL)
700 		return -ENOENT;
701 
702 	mutex_lock(&dev->object_name_lock);
703 	/* prevent races with concurrent gem_close. */
704 	if (obj->handle_count == 0) {
705 		ret = -ENOENT;
706 		goto err;
707 	}
708 
709 	if (!obj->name) {
710 		ret = idr_alloc(&dev->object_name_idr, obj, 1, 0, GFP_KERNEL);
711 		if (ret < 0)
712 			goto err;
713 
714 		obj->name = ret;
715 	}
716 
717 	args->name = (uint64_t) obj->name;
718 	ret = 0;
719 
720 err:
721 	mutex_unlock(&dev->object_name_lock);
722 	drm_gem_object_put_unlocked(obj);
723 	return ret;
724 }
725 
726 /**
727  * drm_gem_open - implementation of the GEM_OPEN ioctl
728  * @dev: drm_device
729  * @data: ioctl data
730  * @file_priv: drm file-private structure
731  *
732  * Open an object using the global name, returning a handle and the size.
733  *
734  * This handle (of course) holds a reference to the object, so the object
735  * will not go away until the handle is deleted.
736  */
737 int
738 drm_gem_open_ioctl(struct drm_device *dev, void *data,
739 		   struct drm_file *file_priv)
740 {
741 	struct drm_gem_open *args = data;
742 	struct drm_gem_object *obj;
743 	int ret;
744 	u32 handle;
745 
746 	if (!drm_core_check_feature(dev, DRIVER_GEM))
747 		return -ENODEV;
748 
749 	mutex_lock(&dev->object_name_lock);
750 	obj = idr_find(&dev->object_name_idr, (int) args->name);
751 	if (obj) {
752 		drm_gem_object_get(obj);
753 	} else {
754 		mutex_unlock(&dev->object_name_lock);
755 		return -ENOENT;
756 	}
757 
758 	/* drm_gem_handle_create_tail unlocks dev->object_name_lock. */
759 	ret = drm_gem_handle_create_tail(file_priv, obj, &handle);
760 	drm_gem_object_put_unlocked(obj);
761 	if (ret)
762 		return ret;
763 
764 	args->handle = handle;
765 	args->size = obj->size;
766 
767 	return 0;
768 }
769 
770 /**
771  * gem_gem_open - initalizes GEM file-private structures at devnode open time
772  * @dev: drm_device which is being opened by userspace
773  * @file_private: drm file-private structure to set up
774  *
775  * Called at device open time, sets up the structure for handling refcounting
776  * of mm objects.
777  */
778 void
779 drm_gem_open(struct drm_device *dev, struct drm_file *file_private)
780 {
781 	idr_init(&file_private->object_idr);
782 	spin_lock_init(&file_private->table_lock);
783 }
784 
785 /**
786  * drm_gem_release - release file-private GEM resources
787  * @dev: drm_device which is being closed by userspace
788  * @file_private: drm file-private structure to clean up
789  *
790  * Called at close time when the filp is going away.
791  *
792  * Releases any remaining references on objects by this filp.
793  */
794 void
795 drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
796 {
797 	idr_for_each(&file_private->object_idr,
798 		     &drm_gem_object_release_handle, file_private);
799 	idr_destroy(&file_private->object_idr);
800 }
801 
802 /**
803  * drm_gem_object_release - release GEM buffer object resources
804  * @obj: GEM buffer object
805  *
806  * This releases any structures and resources used by @obj and is the invers of
807  * drm_gem_object_init().
808  */
809 void
810 drm_gem_object_release(struct drm_gem_object *obj)
811 {
812 	WARN_ON(obj->dma_buf);
813 
814 	if (obj->filp)
815 		fput(obj->filp);
816 
817 	drm_gem_free_mmap_offset(obj);
818 }
819 EXPORT_SYMBOL(drm_gem_object_release);
820 
821 /**
822  * drm_gem_object_free - free a GEM object
823  * @kref: kref of the object to free
824  *
825  * Called after the last reference to the object has been lost.
826  * Must be called holding &drm_device.struct_mutex.
827  *
828  * Frees the object
829  */
830 void
831 drm_gem_object_free(struct kref *kref)
832 {
833 	struct drm_gem_object *obj =
834 		container_of(kref, struct drm_gem_object, refcount);
835 	struct drm_device *dev = obj->dev;
836 
837 	if (dev->driver->gem_free_object_unlocked) {
838 		dev->driver->gem_free_object_unlocked(obj);
839 	} else if (dev->driver->gem_free_object) {
840 		WARN_ON(!mutex_is_locked(&dev->struct_mutex));
841 
842 		dev->driver->gem_free_object(obj);
843 	}
844 }
845 EXPORT_SYMBOL(drm_gem_object_free);
846 
847 /**
848  * drm_gem_object_put_unlocked - drop a GEM buffer object reference
849  * @obj: GEM buffer object
850  *
851  * This releases a reference to @obj. Callers must not hold the
852  * &drm_device.struct_mutex lock when calling this function.
853  *
854  * See also __drm_gem_object_put().
855  */
856 void
857 drm_gem_object_put_unlocked(struct drm_gem_object *obj)
858 {
859 	struct drm_device *dev;
860 
861 	if (!obj)
862 		return;
863 
864 	dev = obj->dev;
865 
866 	if (dev->driver->gem_free_object_unlocked) {
867 		kref_put(&obj->refcount, drm_gem_object_free);
868 	} else {
869 		might_lock(&dev->struct_mutex);
870 		if (kref_put_mutex(&obj->refcount, drm_gem_object_free,
871 				&dev->struct_mutex))
872 			mutex_unlock(&dev->struct_mutex);
873 	}
874 }
875 EXPORT_SYMBOL(drm_gem_object_put_unlocked);
876 
877 /**
878  * drm_gem_object_put - release a GEM buffer object reference
879  * @obj: GEM buffer object
880  *
881  * This releases a reference to @obj. Callers must hold the
882  * &drm_device.struct_mutex lock when calling this function, even when the
883  * driver doesn't use &drm_device.struct_mutex for anything.
884  *
885  * For drivers not encumbered with legacy locking use
886  * drm_gem_object_put_unlocked() instead.
887  */
888 void
889 drm_gem_object_put(struct drm_gem_object *obj)
890 {
891 	if (obj) {
892 		WARN_ON(!mutex_is_locked(&obj->dev->struct_mutex));
893 
894 		kref_put(&obj->refcount, drm_gem_object_free);
895 	}
896 }
897 EXPORT_SYMBOL(drm_gem_object_put);
898 
899 /**
900  * drm_gem_vm_open - vma->ops->open implementation for GEM
901  * @vma: VM area structure
902  *
903  * This function implements the #vm_operations_struct open() callback for GEM
904  * drivers. This must be used together with drm_gem_vm_close().
905  */
906 void drm_gem_vm_open(struct vm_area_struct *vma)
907 {
908 	struct drm_gem_object *obj = vma->vm_private_data;
909 
910 	drm_gem_object_get(obj);
911 }
912 EXPORT_SYMBOL(drm_gem_vm_open);
913 
914 /**
915  * drm_gem_vm_close - vma->ops->close implementation for GEM
916  * @vma: VM area structure
917  *
918  * This function implements the #vm_operations_struct close() callback for GEM
919  * drivers. This must be used together with drm_gem_vm_open().
920  */
921 void drm_gem_vm_close(struct vm_area_struct *vma)
922 {
923 	struct drm_gem_object *obj = vma->vm_private_data;
924 
925 	drm_gem_object_put_unlocked(obj);
926 }
927 EXPORT_SYMBOL(drm_gem_vm_close);
928 
929 /**
930  * drm_gem_mmap_obj - memory map a GEM object
931  * @obj: the GEM object to map
932  * @obj_size: the object size to be mapped, in bytes
933  * @vma: VMA for the area to be mapped
934  *
935  * Set up the VMA to prepare mapping of the GEM object using the gem_vm_ops
936  * provided by the driver. Depending on their requirements, drivers can either
937  * provide a fault handler in their gem_vm_ops (in which case any accesses to
938  * the object will be trapped, to perform migration, GTT binding, surface
939  * register allocation, or performance monitoring), or mmap the buffer memory
940  * synchronously after calling drm_gem_mmap_obj.
941  *
942  * This function is mainly intended to implement the DMABUF mmap operation, when
943  * the GEM object is not looked up based on its fake offset. To implement the
944  * DRM mmap operation, drivers should use the drm_gem_mmap() function.
945  *
946  * drm_gem_mmap_obj() assumes the user is granted access to the buffer while
947  * drm_gem_mmap() prevents unprivileged users from mapping random objects. So
948  * callers must verify access restrictions before calling this helper.
949  *
950  * Return 0 or success or -EINVAL if the object size is smaller than the VMA
951  * size, or if no gem_vm_ops are provided.
952  */
953 int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
954 		     struct vm_area_struct *vma)
955 {
956 	struct drm_device *dev = obj->dev;
957 
958 	/* Check for valid size. */
959 	if (obj_size < vma->vm_end - vma->vm_start)
960 		return -EINVAL;
961 
962 	if (!dev->driver->gem_vm_ops)
963 		return -EINVAL;
964 
965 	vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
966 	vma->vm_ops = dev->driver->gem_vm_ops;
967 	vma->vm_private_data = obj;
968 	vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
969 	vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
970 
971 	/* Take a ref for this mapping of the object, so that the fault
972 	 * handler can dereference the mmap offset's pointer to the object.
973 	 * This reference is cleaned up by the corresponding vm_close
974 	 * (which should happen whether the vma was created by this call, or
975 	 * by a vm_open due to mremap or partial unmap or whatever).
976 	 */
977 	drm_gem_object_get(obj);
978 
979 	return 0;
980 }
981 EXPORT_SYMBOL(drm_gem_mmap_obj);
982 
983 /**
984  * drm_gem_mmap - memory map routine for GEM objects
985  * @filp: DRM file pointer
986  * @vma: VMA for the area to be mapped
987  *
988  * If a driver supports GEM object mapping, mmap calls on the DRM file
989  * descriptor will end up here.
990  *
991  * Look up the GEM object based on the offset passed in (vma->vm_pgoff will
992  * contain the fake offset we created when the GTT map ioctl was called on
993  * the object) and map it with a call to drm_gem_mmap_obj().
994  *
995  * If the caller is not granted access to the buffer object, the mmap will fail
996  * with EACCES. Please see the vma manager for more information.
997  */
998 int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
999 {
1000 	struct drm_file *priv = filp->private_data;
1001 	struct drm_device *dev = priv->minor->dev;
1002 	struct drm_gem_object *obj = NULL;
1003 	struct drm_vma_offset_node *node;
1004 	int ret;
1005 
1006 	if (drm_dev_is_unplugged(dev))
1007 		return -ENODEV;
1008 
1009 	drm_vma_offset_lock_lookup(dev->vma_offset_manager);
1010 	node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager,
1011 						  vma->vm_pgoff,
1012 						  vma_pages(vma));
1013 	if (likely(node)) {
1014 		obj = container_of(node, struct drm_gem_object, vma_node);
1015 		/*
1016 		 * When the object is being freed, after it hits 0-refcnt it
1017 		 * proceeds to tear down the object. In the process it will
1018 		 * attempt to remove the VMA offset and so acquire this
1019 		 * mgr->vm_lock.  Therefore if we find an object with a 0-refcnt
1020 		 * that matches our range, we know it is in the process of being
1021 		 * destroyed and will be freed as soon as we release the lock -
1022 		 * so we have to check for the 0-refcnted object and treat it as
1023 		 * invalid.
1024 		 */
1025 		if (!kref_get_unless_zero(&obj->refcount))
1026 			obj = NULL;
1027 	}
1028 	drm_vma_offset_unlock_lookup(dev->vma_offset_manager);
1029 
1030 	if (!obj)
1031 		return -EINVAL;
1032 
1033 	if (!drm_vma_node_is_allowed(node, priv)) {
1034 		drm_gem_object_put_unlocked(obj);
1035 		return -EACCES;
1036 	}
1037 
1038 	ret = drm_gem_mmap_obj(obj, drm_vma_node_size(node) << PAGE_SHIFT,
1039 			       vma);
1040 
1041 	drm_gem_object_put_unlocked(obj);
1042 
1043 	return ret;
1044 }
1045 EXPORT_SYMBOL(drm_gem_mmap);
1046