Loading...
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 "drmP.h"
39
40/** @file drm_gem.c
41 *
42 * This file provides some of the base ioctls and library routines for
43 * the graphics memory manager implemented by each device driver.
44 *
45 * Because various devices have different requirements in terms of
46 * synchronization and migration strategies, implementing that is left up to
47 * the driver, and all that the general API provides should be generic --
48 * allocating objects, reading/writing data with the cpu, freeing objects.
49 * Even there, platform-dependent optimizations for reading/writing data with
50 * the CPU mean we'll likely hook those out to driver-specific calls. However,
51 * the DRI2 implementation wants to have at least allocate/mmap be generic.
52 *
53 * The goal was to have swap-backed object allocation managed through
54 * struct file. However, file descriptors as handles to a struct file have
55 * two major failings:
56 * - Process limits prevent more than 1024 or so being used at a time by
57 * default.
58 * - Inability to allocate high fds will aggravate the X Server's select()
59 * handling, and likely that of many GL client applications as well.
60 *
61 * This led to a plan of using our own integer IDs (called handles, following
62 * DRM terminology) to mimic fds, and implement the fd syscalls we need as
63 * ioctls. The objects themselves will still include the struct file so
64 * that we can transition to fds if the required kernel infrastructure shows
65 * up at a later date, and as our interface with shmfs for memory allocation.
66 */
67
68/*
69 * We make up offsets for buffer objects so we can recognize them at
70 * mmap time.
71 */
72
73/* pgoff in mmap is an unsigned long, so we need to make sure that
74 * the faked up offset will fit
75 */
76
77#if BITS_PER_LONG == 64
78#define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFFUL >> PAGE_SHIFT) + 1)
79#define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFFUL >> PAGE_SHIFT) * 16)
80#else
81#define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFUL >> PAGE_SHIFT) + 1)
82#define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFUL >> PAGE_SHIFT) * 16)
83#endif
84
85/**
86 * Initialize the GEM device fields
87 */
88
89int
90drm_gem_init(struct drm_device *dev)
91{
92 struct drm_gem_mm *mm;
93
94 spin_lock_init(&dev->object_name_lock);
95 idr_init(&dev->object_name_idr);
96
97 mm = kzalloc(sizeof(struct drm_gem_mm), GFP_KERNEL);
98 if (!mm) {
99 DRM_ERROR("out of memory\n");
100 return -ENOMEM;
101 }
102
103 dev->mm_private = mm;
104
105 if (drm_ht_create(&mm->offset_hash, 12)) {
106 kfree(mm);
107 return -ENOMEM;
108 }
109
110 if (drm_mm_init(&mm->offset_manager, DRM_FILE_PAGE_OFFSET_START,
111 DRM_FILE_PAGE_OFFSET_SIZE)) {
112 drm_ht_remove(&mm->offset_hash);
113 kfree(mm);
114 return -ENOMEM;
115 }
116
117 return 0;
118}
119
120void
121drm_gem_destroy(struct drm_device *dev)
122{
123 struct drm_gem_mm *mm = dev->mm_private;
124
125 drm_mm_takedown(&mm->offset_manager);
126 drm_ht_remove(&mm->offset_hash);
127 kfree(mm);
128 dev->mm_private = NULL;
129}
130
131/**
132 * Initialize an already allocated GEM object of the specified size with
133 * shmfs backing store.
134 */
135int drm_gem_object_init(struct drm_device *dev,
136 struct drm_gem_object *obj, size_t size)
137{
138 BUG_ON((size & (PAGE_SIZE - 1)) != 0);
139
140 obj->dev = dev;
141 obj->filp = shmem_file_setup("drm mm object", size, VM_NORESERVE);
142 if (IS_ERR(obj->filp))
143 return -ENOMEM;
144
145 kref_init(&obj->refcount);
146 atomic_set(&obj->handle_count, 0);
147 obj->size = size;
148
149 return 0;
150}
151EXPORT_SYMBOL(drm_gem_object_init);
152
153/**
154 * Initialize an already allocated GEM object of the specified size with
155 * no GEM provided backing store. Instead the caller is responsible for
156 * backing the object and handling it.
157 */
158int drm_gem_private_object_init(struct drm_device *dev,
159 struct drm_gem_object *obj, size_t size)
160{
161 BUG_ON((size & (PAGE_SIZE - 1)) != 0);
162
163 obj->dev = dev;
164 obj->filp = NULL;
165
166 kref_init(&obj->refcount);
167 atomic_set(&obj->handle_count, 0);
168 obj->size = size;
169
170 return 0;
171}
172EXPORT_SYMBOL(drm_gem_private_object_init);
173
174/**
175 * Allocate a GEM object of the specified size with shmfs backing store
176 */
177struct drm_gem_object *
178drm_gem_object_alloc(struct drm_device *dev, size_t size)
179{
180 struct drm_gem_object *obj;
181
182 obj = kzalloc(sizeof(*obj), GFP_KERNEL);
183 if (!obj)
184 goto free;
185
186 if (drm_gem_object_init(dev, obj, size) != 0)
187 goto free;
188
189 if (dev->driver->gem_init_object != NULL &&
190 dev->driver->gem_init_object(obj) != 0) {
191 goto fput;
192 }
193 return obj;
194fput:
195 /* Object_init mangles the global counters - readjust them. */
196 fput(obj->filp);
197free:
198 kfree(obj);
199 return NULL;
200}
201EXPORT_SYMBOL(drm_gem_object_alloc);
202
203/**
204 * Removes the mapping from handle to filp for this object.
205 */
206int
207drm_gem_handle_delete(struct drm_file *filp, u32 handle)
208{
209 struct drm_device *dev;
210 struct drm_gem_object *obj;
211
212 /* This is gross. The idr system doesn't let us try a delete and
213 * return an error code. It just spews if you fail at deleting.
214 * So, we have to grab a lock around finding the object and then
215 * doing the delete on it and dropping the refcount, or the user
216 * could race us to double-decrement the refcount and cause a
217 * use-after-free later. Given the frequency of our handle lookups,
218 * we may want to use ida for number allocation and a hash table
219 * for the pointers, anyway.
220 */
221 spin_lock(&filp->table_lock);
222
223 /* Check if we currently have a reference on the object */
224 obj = idr_find(&filp->object_idr, handle);
225 if (obj == NULL) {
226 spin_unlock(&filp->table_lock);
227 return -EINVAL;
228 }
229 dev = obj->dev;
230
231 /* Release reference and decrement refcount. */
232 idr_remove(&filp->object_idr, handle);
233 spin_unlock(&filp->table_lock);
234
235 if (dev->driver->gem_close_object)
236 dev->driver->gem_close_object(obj, filp);
237 drm_gem_object_handle_unreference_unlocked(obj);
238
239 return 0;
240}
241EXPORT_SYMBOL(drm_gem_handle_delete);
242
243/**
244 * Create a handle for this object. This adds a handle reference
245 * to the object, which includes a regular reference count. Callers
246 * will likely want to dereference the object afterwards.
247 */
248int
249drm_gem_handle_create(struct drm_file *file_priv,
250 struct drm_gem_object *obj,
251 u32 *handlep)
252{
253 struct drm_device *dev = obj->dev;
254 int ret;
255
256 /*
257 * Get the user-visible handle using idr.
258 */
259again:
260 /* ensure there is space available to allocate a handle */
261 if (idr_pre_get(&file_priv->object_idr, GFP_KERNEL) == 0)
262 return -ENOMEM;
263
264 /* do the allocation under our spinlock */
265 spin_lock(&file_priv->table_lock);
266 ret = idr_get_new_above(&file_priv->object_idr, obj, 1, (int *)handlep);
267 spin_unlock(&file_priv->table_lock);
268 if (ret == -EAGAIN)
269 goto again;
270
271 if (ret != 0)
272 return ret;
273
274 drm_gem_object_handle_reference(obj);
275
276 if (dev->driver->gem_open_object) {
277 ret = dev->driver->gem_open_object(obj, file_priv);
278 if (ret) {
279 drm_gem_handle_delete(file_priv, *handlep);
280 return ret;
281 }
282 }
283
284 return 0;
285}
286EXPORT_SYMBOL(drm_gem_handle_create);
287
288/** Returns a reference to the object named by the handle. */
289struct drm_gem_object *
290drm_gem_object_lookup(struct drm_device *dev, struct drm_file *filp,
291 u32 handle)
292{
293 struct drm_gem_object *obj;
294
295 spin_lock(&filp->table_lock);
296
297 /* Check if we currently have a reference on the object */
298 obj = idr_find(&filp->object_idr, handle);
299 if (obj == NULL) {
300 spin_unlock(&filp->table_lock);
301 return NULL;
302 }
303
304 drm_gem_object_reference(obj);
305
306 spin_unlock(&filp->table_lock);
307
308 return obj;
309}
310EXPORT_SYMBOL(drm_gem_object_lookup);
311
312/**
313 * Releases the handle to an mm object.
314 */
315int
316drm_gem_close_ioctl(struct drm_device *dev, void *data,
317 struct drm_file *file_priv)
318{
319 struct drm_gem_close *args = data;
320 int ret;
321
322 if (!(dev->driver->driver_features & DRIVER_GEM))
323 return -ENODEV;
324
325 ret = drm_gem_handle_delete(file_priv, args->handle);
326
327 return ret;
328}
329
330/**
331 * Create a global name for an object, returning the name.
332 *
333 * Note that the name does not hold a reference; when the object
334 * is freed, the name goes away.
335 */
336int
337drm_gem_flink_ioctl(struct drm_device *dev, void *data,
338 struct drm_file *file_priv)
339{
340 struct drm_gem_flink *args = data;
341 struct drm_gem_object *obj;
342 int ret;
343
344 if (!(dev->driver->driver_features & DRIVER_GEM))
345 return -ENODEV;
346
347 obj = drm_gem_object_lookup(dev, file_priv, args->handle);
348 if (obj == NULL)
349 return -ENOENT;
350
351again:
352 if (idr_pre_get(&dev->object_name_idr, GFP_KERNEL) == 0) {
353 ret = -ENOMEM;
354 goto err;
355 }
356
357 spin_lock(&dev->object_name_lock);
358 if (!obj->name) {
359 ret = idr_get_new_above(&dev->object_name_idr, obj, 1,
360 &obj->name);
361 args->name = (uint64_t) obj->name;
362 spin_unlock(&dev->object_name_lock);
363
364 if (ret == -EAGAIN)
365 goto again;
366
367 if (ret != 0)
368 goto err;
369
370 /* Allocate a reference for the name table. */
371 drm_gem_object_reference(obj);
372 } else {
373 args->name = (uint64_t) obj->name;
374 spin_unlock(&dev->object_name_lock);
375 ret = 0;
376 }
377
378err:
379 drm_gem_object_unreference_unlocked(obj);
380 return ret;
381}
382
383/**
384 * Open an object using the global name, returning a handle and the size.
385 *
386 * This handle (of course) holds a reference to the object, so the object
387 * will not go away until the handle is deleted.
388 */
389int
390drm_gem_open_ioctl(struct drm_device *dev, void *data,
391 struct drm_file *file_priv)
392{
393 struct drm_gem_open *args = data;
394 struct drm_gem_object *obj;
395 int ret;
396 u32 handle;
397
398 if (!(dev->driver->driver_features & DRIVER_GEM))
399 return -ENODEV;
400
401 spin_lock(&dev->object_name_lock);
402 obj = idr_find(&dev->object_name_idr, (int) args->name);
403 if (obj)
404 drm_gem_object_reference(obj);
405 spin_unlock(&dev->object_name_lock);
406 if (!obj)
407 return -ENOENT;
408
409 ret = drm_gem_handle_create(file_priv, obj, &handle);
410 drm_gem_object_unreference_unlocked(obj);
411 if (ret)
412 return ret;
413
414 args->handle = handle;
415 args->size = obj->size;
416
417 return 0;
418}
419
420/**
421 * Called at device open time, sets up the structure for handling refcounting
422 * of mm objects.
423 */
424void
425drm_gem_open(struct drm_device *dev, struct drm_file *file_private)
426{
427 idr_init(&file_private->object_idr);
428 spin_lock_init(&file_private->table_lock);
429}
430
431/**
432 * Called at device close to release the file's
433 * handle references on objects.
434 */
435static int
436drm_gem_object_release_handle(int id, void *ptr, void *data)
437{
438 struct drm_file *file_priv = data;
439 struct drm_gem_object *obj = ptr;
440 struct drm_device *dev = obj->dev;
441
442 if (dev->driver->gem_close_object)
443 dev->driver->gem_close_object(obj, file_priv);
444
445 drm_gem_object_handle_unreference_unlocked(obj);
446
447 return 0;
448}
449
450/**
451 * Called at close time when the filp is going away.
452 *
453 * Releases any remaining references on objects by this filp.
454 */
455void
456drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
457{
458 idr_for_each(&file_private->object_idr,
459 &drm_gem_object_release_handle, file_private);
460
461 idr_remove_all(&file_private->object_idr);
462 idr_destroy(&file_private->object_idr);
463}
464
465void
466drm_gem_object_release(struct drm_gem_object *obj)
467{
468 if (obj->filp)
469 fput(obj->filp);
470}
471EXPORT_SYMBOL(drm_gem_object_release);
472
473/**
474 * Called after the last reference to the object has been lost.
475 * Must be called holding struct_ mutex
476 *
477 * Frees the object
478 */
479void
480drm_gem_object_free(struct kref *kref)
481{
482 struct drm_gem_object *obj = (struct drm_gem_object *) kref;
483 struct drm_device *dev = obj->dev;
484
485 BUG_ON(!mutex_is_locked(&dev->struct_mutex));
486
487 if (dev->driver->gem_free_object != NULL)
488 dev->driver->gem_free_object(obj);
489}
490EXPORT_SYMBOL(drm_gem_object_free);
491
492static void drm_gem_object_ref_bug(struct kref *list_kref)
493{
494 BUG();
495}
496
497/**
498 * Called after the last handle to the object has been closed
499 *
500 * Removes any name for the object. Note that this must be
501 * called before drm_gem_object_free or we'll be touching
502 * freed memory
503 */
504void drm_gem_object_handle_free(struct drm_gem_object *obj)
505{
506 struct drm_device *dev = obj->dev;
507
508 /* Remove any name for this object */
509 spin_lock(&dev->object_name_lock);
510 if (obj->name) {
511 idr_remove(&dev->object_name_idr, obj->name);
512 obj->name = 0;
513 spin_unlock(&dev->object_name_lock);
514 /*
515 * The object name held a reference to this object, drop
516 * that now.
517 *
518 * This cannot be the last reference, since the handle holds one too.
519 */
520 kref_put(&obj->refcount, drm_gem_object_ref_bug);
521 } else
522 spin_unlock(&dev->object_name_lock);
523
524}
525EXPORT_SYMBOL(drm_gem_object_handle_free);
526
527void drm_gem_vm_open(struct vm_area_struct *vma)
528{
529 struct drm_gem_object *obj = vma->vm_private_data;
530
531 drm_gem_object_reference(obj);
532
533 mutex_lock(&obj->dev->struct_mutex);
534 drm_vm_open_locked(vma);
535 mutex_unlock(&obj->dev->struct_mutex);
536}
537EXPORT_SYMBOL(drm_gem_vm_open);
538
539void drm_gem_vm_close(struct vm_area_struct *vma)
540{
541 struct drm_gem_object *obj = vma->vm_private_data;
542 struct drm_device *dev = obj->dev;
543
544 mutex_lock(&dev->struct_mutex);
545 drm_vm_close_locked(vma);
546 drm_gem_object_unreference(obj);
547 mutex_unlock(&dev->struct_mutex);
548}
549EXPORT_SYMBOL(drm_gem_vm_close);
550
551
552/**
553 * drm_gem_mmap - memory map routine for GEM objects
554 * @filp: DRM file pointer
555 * @vma: VMA for the area to be mapped
556 *
557 * If a driver supports GEM object mapping, mmap calls on the DRM file
558 * descriptor will end up here.
559 *
560 * If we find the object based on the offset passed in (vma->vm_pgoff will
561 * contain the fake offset we created when the GTT map ioctl was called on
562 * the object), we set up the driver fault handler so that any accesses
563 * to the object can be trapped, to perform migration, GTT binding, surface
564 * register allocation, or performance monitoring.
565 */
566int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
567{
568 struct drm_file *priv = filp->private_data;
569 struct drm_device *dev = priv->minor->dev;
570 struct drm_gem_mm *mm = dev->mm_private;
571 struct drm_local_map *map = NULL;
572 struct drm_gem_object *obj;
573 struct drm_hash_item *hash;
574 int ret = 0;
575
576 mutex_lock(&dev->struct_mutex);
577
578 if (drm_ht_find_item(&mm->offset_hash, vma->vm_pgoff, &hash)) {
579 mutex_unlock(&dev->struct_mutex);
580 return drm_mmap(filp, vma);
581 }
582
583 map = drm_hash_entry(hash, struct drm_map_list, hash)->map;
584 if (!map ||
585 ((map->flags & _DRM_RESTRICTED) && !capable(CAP_SYS_ADMIN))) {
586 ret = -EPERM;
587 goto out_unlock;
588 }
589
590 /* Check for valid size. */
591 if (map->size < vma->vm_end - vma->vm_start) {
592 ret = -EINVAL;
593 goto out_unlock;
594 }
595
596 obj = map->handle;
597 if (!obj->dev->driver->gem_vm_ops) {
598 ret = -EINVAL;
599 goto out_unlock;
600 }
601
602 vma->vm_flags |= VM_RESERVED | VM_IO | VM_PFNMAP | VM_DONTEXPAND;
603 vma->vm_ops = obj->dev->driver->gem_vm_ops;
604 vma->vm_private_data = map->handle;
605 vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
606
607 /* Take a ref for this mapping of the object, so that the fault
608 * handler can dereference the mmap offset's pointer to the object.
609 * This reference is cleaned up by the corresponding vm_close
610 * (which should happen whether the vma was created by this call, or
611 * by a vm_open due to mremap or partial unmap or whatever).
612 */
613 drm_gem_object_reference(obj);
614
615 vma->vm_file = filp; /* Needed for drm_vm_open() */
616 drm_vm_open_locked(vma);
617
618out_unlock:
619 mutex_unlock(&dev->struct_mutex);
620
621 return ret;
622}
623EXPORT_SYMBOL(drm_gem_mmap);
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 <drm/drmP.h>
40#include <drm/drm_vma_manager.h>
41#include <drm/drm_gem.h>
42#include "drm_internal.h"
43
44/** @file drm_gem.c
45 *
46 * This file provides some of the base ioctls and library routines for
47 * the graphics memory manager implemented by each device driver.
48 *
49 * Because various devices have different requirements in terms of
50 * synchronization and migration strategies, implementing that is left up to
51 * the driver, and all that the general API provides should be generic --
52 * allocating objects, reading/writing data with the cpu, freeing objects.
53 * Even there, platform-dependent optimizations for reading/writing data with
54 * the CPU mean we'll likely hook those out to driver-specific calls. However,
55 * the DRI2 implementation wants to have at least allocate/mmap be generic.
56 *
57 * The goal was to have swap-backed object allocation managed through
58 * struct file. However, file descriptors as handles to a struct file have
59 * two major failings:
60 * - Process limits prevent more than 1024 or so being used at a time by
61 * default.
62 * - Inability to allocate high fds will aggravate the X Server's select()
63 * handling, and likely that of many GL client applications as well.
64 *
65 * This led to a plan of using our own integer IDs (called handles, following
66 * DRM terminology) to mimic fds, and implement the fd syscalls we need as
67 * ioctls. The objects themselves will still include the struct file so
68 * that we can transition to fds if the required kernel infrastructure shows
69 * up at a later date, and as our interface with shmfs for memory allocation.
70 */
71
72/*
73 * We make up offsets for buffer objects so we can recognize them at
74 * mmap time.
75 */
76
77/* pgoff in mmap is an unsigned long, so we need to make sure that
78 * the faked up offset will fit
79 */
80
81#if BITS_PER_LONG == 64
82#define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFFUL >> PAGE_SHIFT) + 1)
83#define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFFUL >> PAGE_SHIFT) * 16)
84#else
85#define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFUL >> PAGE_SHIFT) + 1)
86#define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFUL >> PAGE_SHIFT) * 16)
87#endif
88
89/**
90 * drm_gem_init - Initialize the GEM device fields
91 * @dev: drm_devic structure to initialize
92 */
93int
94drm_gem_init(struct drm_device *dev)
95{
96 struct drm_vma_offset_manager *vma_offset_manager;
97
98 mutex_init(&dev->object_name_lock);
99 idr_init(&dev->object_name_idr);
100
101 vma_offset_manager = kzalloc(sizeof(*vma_offset_manager), GFP_KERNEL);
102 if (!vma_offset_manager) {
103 DRM_ERROR("out of memory\n");
104 return -ENOMEM;
105 }
106
107 dev->vma_offset_manager = vma_offset_manager;
108 drm_vma_offset_manager_init(vma_offset_manager,
109 DRM_FILE_PAGE_OFFSET_START,
110 DRM_FILE_PAGE_OFFSET_SIZE);
111
112 return 0;
113}
114
115void
116drm_gem_destroy(struct drm_device *dev)
117{
118
119 drm_vma_offset_manager_destroy(dev->vma_offset_manager);
120 kfree(dev->vma_offset_manager);
121 dev->vma_offset_manager = NULL;
122}
123
124/**
125 * drm_gem_object_init - initialize an allocated shmem-backed GEM object
126 * @dev: drm_device the object should be initialized for
127 * @obj: drm_gem_object to initialize
128 * @size: object size
129 *
130 * Initialize an already allocated GEM object of the specified size with
131 * shmfs backing store.
132 */
133int drm_gem_object_init(struct drm_device *dev,
134 struct drm_gem_object *obj, size_t size)
135{
136 struct file *filp;
137
138 drm_gem_private_object_init(dev, obj, size);
139
140 filp = shmem_file_setup("drm mm object", size, VM_NORESERVE);
141 if (IS_ERR(filp))
142 return PTR_ERR(filp);
143
144 obj->filp = filp;
145
146 return 0;
147}
148EXPORT_SYMBOL(drm_gem_object_init);
149
150/**
151 * drm_gem_private_object_init - initialize an allocated private GEM object
152 * @dev: drm_device the object should be initialized for
153 * @obj: drm_gem_object to initialize
154 * @size: object size
155 *
156 * Initialize an already allocated GEM object of the specified size with
157 * no GEM provided backing store. Instead the caller is responsible for
158 * backing the object and handling it.
159 */
160void drm_gem_private_object_init(struct drm_device *dev,
161 struct drm_gem_object *obj, size_t size)
162{
163 BUG_ON((size & (PAGE_SIZE - 1)) != 0);
164
165 obj->dev = dev;
166 obj->filp = NULL;
167
168 kref_init(&obj->refcount);
169 obj->handle_count = 0;
170 obj->size = size;
171 drm_vma_node_reset(&obj->vma_node);
172}
173EXPORT_SYMBOL(drm_gem_private_object_init);
174
175static void
176drm_gem_remove_prime_handles(struct drm_gem_object *obj, struct drm_file *filp)
177{
178 /*
179 * Note: obj->dma_buf can't disappear as long as we still hold a
180 * handle reference in obj->handle_count.
181 */
182 mutex_lock(&filp->prime.lock);
183 if (obj->dma_buf) {
184 drm_prime_remove_buf_handle_locked(&filp->prime,
185 obj->dma_buf);
186 }
187 mutex_unlock(&filp->prime.lock);
188}
189
190/**
191 * drm_gem_object_handle_free - release resources bound to userspace handles
192 * @obj: GEM object to clean up.
193 *
194 * Called after the last handle to the object has been closed
195 *
196 * Removes any name for the object. Note that this must be
197 * called before drm_gem_object_free or we'll be touching
198 * freed memory
199 */
200static void drm_gem_object_handle_free(struct drm_gem_object *obj)
201{
202 struct drm_device *dev = obj->dev;
203
204 /* Remove any name for this object */
205 if (obj->name) {
206 idr_remove(&dev->object_name_idr, obj->name);
207 obj->name = 0;
208 }
209}
210
211static void drm_gem_object_exported_dma_buf_free(struct drm_gem_object *obj)
212{
213 /* Unbreak the reference cycle if we have an exported dma_buf. */
214 if (obj->dma_buf) {
215 dma_buf_put(obj->dma_buf);
216 obj->dma_buf = NULL;
217 }
218}
219
220static void
221drm_gem_object_handle_unreference_unlocked(struct drm_gem_object *obj)
222{
223 struct drm_device *dev = obj->dev;
224 bool final = false;
225
226 if (WARN_ON(obj->handle_count == 0))
227 return;
228
229 /*
230 * Must bump handle count first as this may be the last
231 * ref, in which case the object would disappear before we
232 * checked for a name
233 */
234
235 mutex_lock(&dev->object_name_lock);
236 if (--obj->handle_count == 0) {
237 drm_gem_object_handle_free(obj);
238 drm_gem_object_exported_dma_buf_free(obj);
239 final = true;
240 }
241 mutex_unlock(&dev->object_name_lock);
242
243 if (final)
244 drm_gem_object_unreference_unlocked(obj);
245}
246
247/*
248 * Called at device or object close to release the file's
249 * handle references on objects.
250 */
251static int
252drm_gem_object_release_handle(int id, void *ptr, void *data)
253{
254 struct drm_file *file_priv = data;
255 struct drm_gem_object *obj = ptr;
256 struct drm_device *dev = obj->dev;
257
258 if (drm_core_check_feature(dev, DRIVER_PRIME))
259 drm_gem_remove_prime_handles(obj, file_priv);
260 drm_vma_node_revoke(&obj->vma_node, file_priv);
261
262 if (dev->driver->gem_close_object)
263 dev->driver->gem_close_object(obj, file_priv);
264
265 drm_gem_object_handle_unreference_unlocked(obj);
266
267 return 0;
268}
269
270/**
271 * drm_gem_handle_delete - deletes the given file-private handle
272 * @filp: drm file-private structure to use for the handle look up
273 * @handle: userspace handle to delete
274 *
275 * Removes the GEM handle from the @filp lookup table which has been added with
276 * drm_gem_handle_create(). If this is the last handle also cleans up linked
277 * resources like GEM names.
278 */
279int
280drm_gem_handle_delete(struct drm_file *filp, u32 handle)
281{
282 struct drm_gem_object *obj;
283
284 /* This is gross. The idr system doesn't let us try a delete and
285 * return an error code. It just spews if you fail at deleting.
286 * So, we have to grab a lock around finding the object and then
287 * doing the delete on it and dropping the refcount, or the user
288 * could race us to double-decrement the refcount and cause a
289 * use-after-free later. Given the frequency of our handle lookups,
290 * we may want to use ida for number allocation and a hash table
291 * for the pointers, anyway.
292 */
293 spin_lock(&filp->table_lock);
294
295 /* Check if we currently have a reference on the object */
296 obj = idr_replace(&filp->object_idr, NULL, handle);
297 spin_unlock(&filp->table_lock);
298 if (IS_ERR_OR_NULL(obj))
299 return -EINVAL;
300
301 /* Release driver's reference and decrement refcount. */
302 drm_gem_object_release_handle(handle, obj, filp);
303
304 /* And finally make the handle available for future allocations. */
305 spin_lock(&filp->table_lock);
306 idr_remove(&filp->object_idr, handle);
307 spin_unlock(&filp->table_lock);
308
309 return 0;
310}
311EXPORT_SYMBOL(drm_gem_handle_delete);
312
313/**
314 * drm_gem_dumb_destroy - dumb fb callback helper for gem based drivers
315 * @file: drm file-private structure to remove the dumb handle from
316 * @dev: corresponding drm_device
317 * @handle: the dumb handle to remove
318 *
319 * This implements the ->dumb_destroy kms driver callback for drivers which use
320 * gem to manage their backing storage.
321 */
322int drm_gem_dumb_destroy(struct drm_file *file,
323 struct drm_device *dev,
324 uint32_t handle)
325{
326 return drm_gem_handle_delete(file, handle);
327}
328EXPORT_SYMBOL(drm_gem_dumb_destroy);
329
330/**
331 * drm_gem_handle_create_tail - internal functions to create a handle
332 * @file_priv: drm file-private structure to register the handle for
333 * @obj: object to register
334 * @handlep: pointer to return the created handle to the caller
335 *
336 * This expects the dev->object_name_lock to be held already and will drop it
337 * before returning. Used to avoid races in establishing new handles when
338 * importing an object from either an flink name or a dma-buf.
339 *
340 * Handles must be release again through drm_gem_handle_delete(). This is done
341 * when userspace closes @file_priv for all attached handles, or through the
342 * GEM_CLOSE ioctl for individual handles.
343 */
344int
345drm_gem_handle_create_tail(struct drm_file *file_priv,
346 struct drm_gem_object *obj,
347 u32 *handlep)
348{
349 struct drm_device *dev = obj->dev;
350 u32 handle;
351 int ret;
352
353 WARN_ON(!mutex_is_locked(&dev->object_name_lock));
354 if (obj->handle_count++ == 0)
355 drm_gem_object_reference(obj);
356
357 /*
358 * Get the user-visible handle using idr. Preload and perform
359 * allocation under our spinlock.
360 */
361 idr_preload(GFP_KERNEL);
362 spin_lock(&file_priv->table_lock);
363
364 ret = idr_alloc(&file_priv->object_idr, obj, 1, 0, GFP_NOWAIT);
365
366 spin_unlock(&file_priv->table_lock);
367 idr_preload_end();
368
369 mutex_unlock(&dev->object_name_lock);
370 if (ret < 0)
371 goto err_unref;
372
373 handle = ret;
374
375 ret = drm_vma_node_allow(&obj->vma_node, file_priv);
376 if (ret)
377 goto err_remove;
378
379 if (dev->driver->gem_open_object) {
380 ret = dev->driver->gem_open_object(obj, file_priv);
381 if (ret)
382 goto err_revoke;
383 }
384
385 *handlep = handle;
386 return 0;
387
388err_revoke:
389 drm_vma_node_revoke(&obj->vma_node, file_priv);
390err_remove:
391 spin_lock(&file_priv->table_lock);
392 idr_remove(&file_priv->object_idr, handle);
393 spin_unlock(&file_priv->table_lock);
394err_unref:
395 drm_gem_object_handle_unreference_unlocked(obj);
396 return ret;
397}
398
399/**
400 * drm_gem_handle_create - create a gem handle for an object
401 * @file_priv: drm file-private structure to register the handle for
402 * @obj: object to register
403 * @handlep: pionter to return the created handle to the caller
404 *
405 * Create a handle for this object. This adds a handle reference
406 * to the object, which includes a regular reference count. Callers
407 * will likely want to dereference the object afterwards.
408 */
409int drm_gem_handle_create(struct drm_file *file_priv,
410 struct drm_gem_object *obj,
411 u32 *handlep)
412{
413 mutex_lock(&obj->dev->object_name_lock);
414
415 return drm_gem_handle_create_tail(file_priv, obj, handlep);
416}
417EXPORT_SYMBOL(drm_gem_handle_create);
418
419
420/**
421 * drm_gem_free_mmap_offset - release a fake mmap offset for an object
422 * @obj: obj in question
423 *
424 * This routine frees fake offsets allocated by drm_gem_create_mmap_offset().
425 *
426 * Note that drm_gem_object_release() already calls this function, so drivers
427 * don't have to take care of releasing the mmap offset themselves when freeing
428 * the GEM object.
429 */
430void
431drm_gem_free_mmap_offset(struct drm_gem_object *obj)
432{
433 struct drm_device *dev = obj->dev;
434
435 drm_vma_offset_remove(dev->vma_offset_manager, &obj->vma_node);
436}
437EXPORT_SYMBOL(drm_gem_free_mmap_offset);
438
439/**
440 * drm_gem_create_mmap_offset_size - create a fake mmap offset for an object
441 * @obj: obj in question
442 * @size: the virtual size
443 *
444 * GEM memory mapping works by handing back to userspace a fake mmap offset
445 * it can use in a subsequent mmap(2) call. The DRM core code then looks
446 * up the object based on the offset and sets up the various memory mapping
447 * structures.
448 *
449 * This routine allocates and attaches a fake offset for @obj, in cases where
450 * the virtual size differs from the physical size (ie. obj->size). Otherwise
451 * just use drm_gem_create_mmap_offset().
452 *
453 * This function is idempotent and handles an already allocated mmap offset
454 * transparently. Drivers do not need to check for this case.
455 */
456int
457drm_gem_create_mmap_offset_size(struct drm_gem_object *obj, size_t size)
458{
459 struct drm_device *dev = obj->dev;
460
461 return drm_vma_offset_add(dev->vma_offset_manager, &obj->vma_node,
462 size / PAGE_SIZE);
463}
464EXPORT_SYMBOL(drm_gem_create_mmap_offset_size);
465
466/**
467 * drm_gem_create_mmap_offset - create a fake mmap offset for an object
468 * @obj: obj in question
469 *
470 * GEM memory mapping works by handing back to userspace a fake mmap offset
471 * it can use in a subsequent mmap(2) call. The DRM core code then looks
472 * up the object based on the offset and sets up the various memory mapping
473 * structures.
474 *
475 * This routine allocates and attaches a fake offset for @obj.
476 *
477 * Drivers can call drm_gem_free_mmap_offset() before freeing @obj to release
478 * the fake offset again.
479 */
480int drm_gem_create_mmap_offset(struct drm_gem_object *obj)
481{
482 return drm_gem_create_mmap_offset_size(obj, obj->size);
483}
484EXPORT_SYMBOL(drm_gem_create_mmap_offset);
485
486/**
487 * drm_gem_get_pages - helper to allocate backing pages for a GEM object
488 * from shmem
489 * @obj: obj in question
490 *
491 * This reads the page-array of the shmem-backing storage of the given gem
492 * object. An array of pages is returned. If a page is not allocated or
493 * swapped-out, this will allocate/swap-in the required pages. Note that the
494 * whole object is covered by the page-array and pinned in memory.
495 *
496 * Use drm_gem_put_pages() to release the array and unpin all pages.
497 *
498 * This uses the GFP-mask set on the shmem-mapping (see mapping_set_gfp_mask()).
499 * If you require other GFP-masks, you have to do those allocations yourself.
500 *
501 * Note that you are not allowed to change gfp-zones during runtime. That is,
502 * shmem_read_mapping_page_gfp() must be called with the same gfp_zone(gfp) as
503 * set during initialization. If you have special zone constraints, set them
504 * after drm_gem_init_object() via mapping_set_gfp_mask(). shmem-core takes care
505 * to keep pages in the required zone during swap-in.
506 */
507struct page **drm_gem_get_pages(struct drm_gem_object *obj)
508{
509 struct address_space *mapping;
510 struct page *p, **pages;
511 int i, npages;
512
513 /* This is the shared memory object that backs the GEM resource */
514 mapping = obj->filp->f_mapping;
515
516 /* We already BUG_ON() for non-page-aligned sizes in
517 * drm_gem_object_init(), so we should never hit this unless
518 * driver author is doing something really wrong:
519 */
520 WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0);
521
522 npages = obj->size >> PAGE_SHIFT;
523
524 pages = drm_malloc_ab(npages, sizeof(struct page *));
525 if (pages == NULL)
526 return ERR_PTR(-ENOMEM);
527
528 for (i = 0; i < npages; i++) {
529 p = shmem_read_mapping_page(mapping, i);
530 if (IS_ERR(p))
531 goto fail;
532 pages[i] = p;
533
534 /* Make sure shmem keeps __GFP_DMA32 allocated pages in the
535 * correct region during swapin. Note that this requires
536 * __GFP_DMA32 to be set in mapping_gfp_mask(inode->i_mapping)
537 * so shmem can relocate pages during swapin if required.
538 */
539 BUG_ON(mapping_gfp_constraint(mapping, __GFP_DMA32) &&
540 (page_to_pfn(p) >= 0x00100000UL));
541 }
542
543 return pages;
544
545fail:
546 while (i--)
547 put_page(pages[i]);
548
549 drm_free_large(pages);
550 return ERR_CAST(p);
551}
552EXPORT_SYMBOL(drm_gem_get_pages);
553
554/**
555 * drm_gem_put_pages - helper to free backing pages for a GEM object
556 * @obj: obj in question
557 * @pages: pages to free
558 * @dirty: if true, pages will be marked as dirty
559 * @accessed: if true, the pages will be marked as accessed
560 */
561void drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages,
562 bool dirty, bool accessed)
563{
564 int i, npages;
565
566 /* We already BUG_ON() for non-page-aligned sizes in
567 * drm_gem_object_init(), so we should never hit this unless
568 * driver author is doing something really wrong:
569 */
570 WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0);
571
572 npages = obj->size >> PAGE_SHIFT;
573
574 for (i = 0; i < npages; i++) {
575 if (dirty)
576 set_page_dirty(pages[i]);
577
578 if (accessed)
579 mark_page_accessed(pages[i]);
580
581 /* Undo the reference we took when populating the table */
582 put_page(pages[i]);
583 }
584
585 drm_free_large(pages);
586}
587EXPORT_SYMBOL(drm_gem_put_pages);
588
589/**
590 * drm_gem_object_lookup - look up a GEM object from it's handle
591 * @filp: DRM file private date
592 * @handle: userspace handle
593 *
594 * Returns:
595 *
596 * A reference to the object named by the handle if such exists on @filp, NULL
597 * otherwise.
598 */
599struct drm_gem_object *
600drm_gem_object_lookup(struct drm_file *filp, u32 handle)
601{
602 struct drm_gem_object *obj;
603
604 spin_lock(&filp->table_lock);
605
606 /* Check if we currently have a reference on the object */
607 obj = idr_find(&filp->object_idr, handle);
608 if (obj)
609 drm_gem_object_reference(obj);
610
611 spin_unlock(&filp->table_lock);
612
613 return obj;
614}
615EXPORT_SYMBOL(drm_gem_object_lookup);
616
617/**
618 * drm_gem_close_ioctl - implementation of the GEM_CLOSE ioctl
619 * @dev: drm_device
620 * @data: ioctl data
621 * @file_priv: drm file-private structure
622 *
623 * Releases the handle to an mm object.
624 */
625int
626drm_gem_close_ioctl(struct drm_device *dev, void *data,
627 struct drm_file *file_priv)
628{
629 struct drm_gem_close *args = data;
630 int ret;
631
632 if (!drm_core_check_feature(dev, DRIVER_GEM))
633 return -ENODEV;
634
635 ret = drm_gem_handle_delete(file_priv, args->handle);
636
637 return ret;
638}
639
640/**
641 * drm_gem_flink_ioctl - implementation of the GEM_FLINK ioctl
642 * @dev: drm_device
643 * @data: ioctl data
644 * @file_priv: drm file-private structure
645 *
646 * Create a global name for an object, returning the name.
647 *
648 * Note that the name does not hold a reference; when the object
649 * is freed, the name goes away.
650 */
651int
652drm_gem_flink_ioctl(struct drm_device *dev, void *data,
653 struct drm_file *file_priv)
654{
655 struct drm_gem_flink *args = data;
656 struct drm_gem_object *obj;
657 int ret;
658
659 if (!drm_core_check_feature(dev, DRIVER_GEM))
660 return -ENODEV;
661
662 obj = drm_gem_object_lookup(file_priv, args->handle);
663 if (obj == NULL)
664 return -ENOENT;
665
666 mutex_lock(&dev->object_name_lock);
667 /* prevent races with concurrent gem_close. */
668 if (obj->handle_count == 0) {
669 ret = -ENOENT;
670 goto err;
671 }
672
673 if (!obj->name) {
674 ret = idr_alloc(&dev->object_name_idr, obj, 1, 0, GFP_KERNEL);
675 if (ret < 0)
676 goto err;
677
678 obj->name = ret;
679 }
680
681 args->name = (uint64_t) obj->name;
682 ret = 0;
683
684err:
685 mutex_unlock(&dev->object_name_lock);
686 drm_gem_object_unreference_unlocked(obj);
687 return ret;
688}
689
690/**
691 * drm_gem_open - implementation of the GEM_OPEN ioctl
692 * @dev: drm_device
693 * @data: ioctl data
694 * @file_priv: drm file-private structure
695 *
696 * Open an object using the global name, returning a handle and the size.
697 *
698 * This handle (of course) holds a reference to the object, so the object
699 * will not go away until the handle is deleted.
700 */
701int
702drm_gem_open_ioctl(struct drm_device *dev, void *data,
703 struct drm_file *file_priv)
704{
705 struct drm_gem_open *args = data;
706 struct drm_gem_object *obj;
707 int ret;
708 u32 handle;
709
710 if (!drm_core_check_feature(dev, DRIVER_GEM))
711 return -ENODEV;
712
713 mutex_lock(&dev->object_name_lock);
714 obj = idr_find(&dev->object_name_idr, (int) args->name);
715 if (obj) {
716 drm_gem_object_reference(obj);
717 } else {
718 mutex_unlock(&dev->object_name_lock);
719 return -ENOENT;
720 }
721
722 /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */
723 ret = drm_gem_handle_create_tail(file_priv, obj, &handle);
724 drm_gem_object_unreference_unlocked(obj);
725 if (ret)
726 return ret;
727
728 args->handle = handle;
729 args->size = obj->size;
730
731 return 0;
732}
733
734/**
735 * gem_gem_open - initalizes GEM file-private structures at devnode open time
736 * @dev: drm_device which is being opened by userspace
737 * @file_private: drm file-private structure to set up
738 *
739 * Called at device open time, sets up the structure for handling refcounting
740 * of mm objects.
741 */
742void
743drm_gem_open(struct drm_device *dev, struct drm_file *file_private)
744{
745 idr_init(&file_private->object_idr);
746 spin_lock_init(&file_private->table_lock);
747}
748
749/**
750 * drm_gem_release - release file-private GEM resources
751 * @dev: drm_device which is being closed by userspace
752 * @file_private: drm file-private structure to clean up
753 *
754 * Called at close time when the filp is going away.
755 *
756 * Releases any remaining references on objects by this filp.
757 */
758void
759drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
760{
761 idr_for_each(&file_private->object_idr,
762 &drm_gem_object_release_handle, file_private);
763 idr_destroy(&file_private->object_idr);
764}
765
766/**
767 * drm_gem_object_release - release GEM buffer object resources
768 * @obj: GEM buffer object
769 *
770 * This releases any structures and resources used by @obj and is the invers of
771 * drm_gem_object_init().
772 */
773void
774drm_gem_object_release(struct drm_gem_object *obj)
775{
776 WARN_ON(obj->dma_buf);
777
778 if (obj->filp)
779 fput(obj->filp);
780
781 drm_gem_free_mmap_offset(obj);
782}
783EXPORT_SYMBOL(drm_gem_object_release);
784
785/**
786 * drm_gem_object_free - free a GEM object
787 * @kref: kref of the object to free
788 *
789 * Called after the last reference to the object has been lost.
790 * Must be called holding &drm_device->struct_mutex.
791 *
792 * Frees the object
793 */
794void
795drm_gem_object_free(struct kref *kref)
796{
797 struct drm_gem_object *obj =
798 container_of(kref, struct drm_gem_object, refcount);
799 struct drm_device *dev = obj->dev;
800
801 if (dev->driver->gem_free_object_unlocked) {
802 dev->driver->gem_free_object_unlocked(obj);
803 } else if (dev->driver->gem_free_object) {
804 WARN_ON(!mutex_is_locked(&dev->struct_mutex));
805
806 dev->driver->gem_free_object(obj);
807 }
808}
809EXPORT_SYMBOL(drm_gem_object_free);
810
811/**
812 * drm_gem_object_unreference_unlocked - release a GEM BO reference
813 * @obj: GEM buffer object
814 *
815 * This releases a reference to @obj. Callers must not hold the
816 * dev->struct_mutex lock when calling this function.
817 *
818 * See also __drm_gem_object_unreference().
819 */
820void
821drm_gem_object_unreference_unlocked(struct drm_gem_object *obj)
822{
823 struct drm_device *dev;
824
825 if (!obj)
826 return;
827
828 dev = obj->dev;
829 might_lock(&dev->struct_mutex);
830
831 if (dev->driver->gem_free_object_unlocked)
832 kref_put(&obj->refcount, drm_gem_object_free);
833 else if (kref_put_mutex(&obj->refcount, drm_gem_object_free,
834 &dev->struct_mutex))
835 mutex_unlock(&dev->struct_mutex);
836}
837EXPORT_SYMBOL(drm_gem_object_unreference_unlocked);
838
839/**
840 * drm_gem_object_unreference - release a GEM BO reference
841 * @obj: GEM buffer object
842 *
843 * This releases a reference to @obj. Callers must hold the dev->struct_mutex
844 * lock when calling this function, even when the driver doesn't use
845 * dev->struct_mutex for anything.
846 *
847 * For drivers not encumbered with legacy locking use
848 * drm_gem_object_unreference_unlocked() instead.
849 */
850void
851drm_gem_object_unreference(struct drm_gem_object *obj)
852{
853 if (obj) {
854 WARN_ON(!mutex_is_locked(&obj->dev->struct_mutex));
855
856 kref_put(&obj->refcount, drm_gem_object_free);
857 }
858}
859EXPORT_SYMBOL(drm_gem_object_unreference);
860
861/**
862 * drm_gem_vm_open - vma->ops->open implementation for GEM
863 * @vma: VM area structure
864 *
865 * This function implements the #vm_operations_struct open() callback for GEM
866 * drivers. This must be used together with drm_gem_vm_close().
867 */
868void drm_gem_vm_open(struct vm_area_struct *vma)
869{
870 struct drm_gem_object *obj = vma->vm_private_data;
871
872 drm_gem_object_reference(obj);
873}
874EXPORT_SYMBOL(drm_gem_vm_open);
875
876/**
877 * drm_gem_vm_close - vma->ops->close implementation for GEM
878 * @vma: VM area structure
879 *
880 * This function implements the #vm_operations_struct close() callback for GEM
881 * drivers. This must be used together with drm_gem_vm_open().
882 */
883void drm_gem_vm_close(struct vm_area_struct *vma)
884{
885 struct drm_gem_object *obj = vma->vm_private_data;
886
887 drm_gem_object_unreference_unlocked(obj);
888}
889EXPORT_SYMBOL(drm_gem_vm_close);
890
891/**
892 * drm_gem_mmap_obj - memory map a GEM object
893 * @obj: the GEM object to map
894 * @obj_size: the object size to be mapped, in bytes
895 * @vma: VMA for the area to be mapped
896 *
897 * Set up the VMA to prepare mapping of the GEM object using the gem_vm_ops
898 * provided by the driver. Depending on their requirements, drivers can either
899 * provide a fault handler in their gem_vm_ops (in which case any accesses to
900 * the object will be trapped, to perform migration, GTT binding, surface
901 * register allocation, or performance monitoring), or mmap the buffer memory
902 * synchronously after calling drm_gem_mmap_obj.
903 *
904 * This function is mainly intended to implement the DMABUF mmap operation, when
905 * the GEM object is not looked up based on its fake offset. To implement the
906 * DRM mmap operation, drivers should use the drm_gem_mmap() function.
907 *
908 * drm_gem_mmap_obj() assumes the user is granted access to the buffer while
909 * drm_gem_mmap() prevents unprivileged users from mapping random objects. So
910 * callers must verify access restrictions before calling this helper.
911 *
912 * Return 0 or success or -EINVAL if the object size is smaller than the VMA
913 * size, or if no gem_vm_ops are provided.
914 */
915int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
916 struct vm_area_struct *vma)
917{
918 struct drm_device *dev = obj->dev;
919
920 /* Check for valid size. */
921 if (obj_size < vma->vm_end - vma->vm_start)
922 return -EINVAL;
923
924 if (!dev->driver->gem_vm_ops)
925 return -EINVAL;
926
927 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
928 vma->vm_ops = dev->driver->gem_vm_ops;
929 vma->vm_private_data = obj;
930 vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
931
932 /* Take a ref for this mapping of the object, so that the fault
933 * handler can dereference the mmap offset's pointer to the object.
934 * This reference is cleaned up by the corresponding vm_close
935 * (which should happen whether the vma was created by this call, or
936 * by a vm_open due to mremap or partial unmap or whatever).
937 */
938 drm_gem_object_reference(obj);
939
940 return 0;
941}
942EXPORT_SYMBOL(drm_gem_mmap_obj);
943
944/**
945 * drm_gem_mmap - memory map routine for GEM objects
946 * @filp: DRM file pointer
947 * @vma: VMA for the area to be mapped
948 *
949 * If a driver supports GEM object mapping, mmap calls on the DRM file
950 * descriptor will end up here.
951 *
952 * Look up the GEM object based on the offset passed in (vma->vm_pgoff will
953 * contain the fake offset we created when the GTT map ioctl was called on
954 * the object) and map it with a call to drm_gem_mmap_obj().
955 *
956 * If the caller is not granted access to the buffer object, the mmap will fail
957 * with EACCES. Please see the vma manager for more information.
958 */
959int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
960{
961 struct drm_file *priv = filp->private_data;
962 struct drm_device *dev = priv->minor->dev;
963 struct drm_gem_object *obj = NULL;
964 struct drm_vma_offset_node *node;
965 int ret;
966
967 if (drm_device_is_unplugged(dev))
968 return -ENODEV;
969
970 drm_vma_offset_lock_lookup(dev->vma_offset_manager);
971 node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager,
972 vma->vm_pgoff,
973 vma_pages(vma));
974 if (likely(node)) {
975 obj = container_of(node, struct drm_gem_object, vma_node);
976 /*
977 * When the object is being freed, after it hits 0-refcnt it
978 * proceeds to tear down the object. In the process it will
979 * attempt to remove the VMA offset and so acquire this
980 * mgr->vm_lock. Therefore if we find an object with a 0-refcnt
981 * that matches our range, we know it is in the process of being
982 * destroyed and will be freed as soon as we release the lock -
983 * so we have to check for the 0-refcnted object and treat it as
984 * invalid.
985 */
986 if (!kref_get_unless_zero(&obj->refcount))
987 obj = NULL;
988 }
989 drm_vma_offset_unlock_lookup(dev->vma_offset_manager);
990
991 if (!obj)
992 return -EINVAL;
993
994 if (!drm_vma_node_is_allowed(node, priv)) {
995 drm_gem_object_unreference_unlocked(obj);
996 return -EACCES;
997 }
998
999 ret = drm_gem_mmap_obj(obj, drm_vma_node_size(node) << PAGE_SHIFT,
1000 vma);
1001
1002 drm_gem_object_unreference_unlocked(obj);
1003
1004 return ret;
1005}
1006EXPORT_SYMBOL(drm_gem_mmap);