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 "drmP.h"
38
39 /** @file drm_gem.c
40 *
41 * This file provides some of the base ioctls and library routines for
42 * the graphics memory manager implemented by each device driver.
43 *
44 * Because various devices have different requirements in terms of
45 * synchronization and migration strategies, implementing that is left up to
46 * the driver, and all that the general API provides should be generic --
47 * allocating objects, reading/writing data with the cpu, freeing objects.
48 * Even there, platform-dependent optimizations for reading/writing data with
49 * the CPU mean we'll likely hook those out to driver-specific calls. However,
50 * the DRI2 implementation wants to have at least allocate/mmap be generic.
51 *
52 * The goal was to have swap-backed object allocation managed through
53 * struct file. However, file descriptors as handles to a struct file have
54 * two major failings:
55 * - Process limits prevent more than 1024 or so being used at a time by
56 * default.
57 * - Inability to allocate high fds will aggravate the X Server's select()
58 * handling, and likely that of many GL client applications as well.
59 *
60 * This led to a plan of using our own integer IDs (called handles, following
61 * DRM terminology) to mimic fds, and implement the fd syscalls we need as
62 * ioctls. The objects themselves will still include the struct file so
63 * that we can transition to fds if the required kernel infrastructure shows
64 * up at a later date, and as our interface with shmfs for memory allocation.
65 */
66
67 /*
68 * We make up offsets for buffer objects so we can recognize them at
69 * mmap time.
70 */
71 #define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFFUL >> PAGE_SHIFT) + 1)
72 #define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFFUL >> PAGE_SHIFT) * 16)
73
74 /**
75 * Initialize the GEM device fields
76 */
77
78 int
79 drm_gem_init(struct drm_device *dev)
80 {
81 struct drm_gem_mm *mm;
82
83 spin_lock_init(&dev->object_name_lock);
84 idr_init(&dev->object_name_idr);
85 atomic_set(&dev->object_count, 0);
86 atomic_set(&dev->object_memory, 0);
87 atomic_set(&dev->pin_count, 0);
88 atomic_set(&dev->pin_memory, 0);
89 atomic_set(&dev->gtt_count, 0);
90 atomic_set(&dev->gtt_memory, 0);
91
92 mm = kzalloc(sizeof(struct drm_gem_mm), GFP_KERNEL);
93 if (!mm) {
94 DRM_ERROR("out of memory\n");
95 return -ENOMEM;
96 }
97
98 dev->mm_private = mm;
99
100 if (drm_ht_create(&mm->offset_hash, 19)) {
101 kfree(mm);
102 return -ENOMEM;
103 }
104
105 if (drm_mm_init(&mm->offset_manager, DRM_FILE_PAGE_OFFSET_START,
106 DRM_FILE_PAGE_OFFSET_SIZE)) {
107 drm_ht_remove(&mm->offset_hash);
108 kfree(mm);
109 return -ENOMEM;
110 }
111
112 return 0;
113 }
114
115 void
116 drm_gem_destroy(struct drm_device *dev)
117 {
118 struct drm_gem_mm *mm = dev->mm_private;
119
120 drm_mm_takedown(&mm->offset_manager);
121 drm_ht_remove(&mm->offset_hash);
122 kfree(mm);
123 dev->mm_private = NULL;
124 }
125
126 /**
127 * Allocate a GEM object of the specified size with shmfs backing store
128 */
129 struct drm_gem_object *
130 drm_gem_object_alloc(struct drm_device *dev, size_t size)
131 {
132 struct drm_gem_object *obj;
133
134 BUG_ON((size & (PAGE_SIZE - 1)) != 0);
135
136 obj = kzalloc(sizeof(*obj), GFP_KERNEL);
137 if (!obj)
138 goto free;
139
140 obj->dev = dev;
141 obj->filp = shmem_file_setup("drm mm object", size, VM_NORESERVE);
142 if (IS_ERR(obj->filp))
143 goto free;
144
145 kref_init(&obj->refcount);
146 kref_init(&obj->handlecount);
147 obj->size = size;
148 if (dev->driver->gem_init_object != NULL &&
149 dev->driver->gem_init_object(obj) != 0) {
150 goto fput;
151 }
152 atomic_inc(&dev->object_count);
153 atomic_add(obj->size, &dev->object_memory);
154 return obj;
155 fput:
156 fput(obj->filp);
157 free:
158 kfree(obj);
159 return NULL;
160 }
161 EXPORT_SYMBOL(drm_gem_object_alloc);
162
163 /**
164 * Removes the mapping from handle to filp for this object.
165 */
166 static int
167 drm_gem_handle_delete(struct drm_file *filp, int handle)
168 {
169 struct drm_device *dev;
170 struct drm_gem_object *obj;
171
172 /* This is gross. The idr system doesn't let us try a delete and
173 * return an error code. It just spews if you fail at deleting.
174 * So, we have to grab a lock around finding the object and then
175 * doing the delete on it and dropping the refcount, or the user
176 * could race us to double-decrement the refcount and cause a
177 * use-after-free later. Given the frequency of our handle lookups,
178 * we may want to use ida for number allocation and a hash table
179 * for the pointers, anyway.
180 */
181 spin_lock(&filp->table_lock);
182
183 /* Check if we currently have a reference on the object */
184 obj = idr_find(&filp->object_idr, handle);
185 if (obj == NULL) {
186 spin_unlock(&filp->table_lock);
187 return -EINVAL;
188 }
189 dev = obj->dev;
190
191 /* Release reference and decrement refcount. */
192 idr_remove(&filp->object_idr, handle);
193 spin_unlock(&filp->table_lock);
194
195 mutex_lock(&dev->struct_mutex);
196 drm_gem_object_handle_unreference(obj);
197 mutex_unlock(&dev->struct_mutex);
198
199 return 0;
200 }
201
202 /**
203 * Create a handle for this object. This adds a handle reference
204 * to the object, which includes a regular reference count. Callers
205 * will likely want to dereference the object afterwards.
206 */
207 int
208 drm_gem_handle_create(struct drm_file *file_priv,
209 struct drm_gem_object *obj,
210 int *handlep)
211 {
212 int ret;
213
214 /*
215 * Get the user-visible handle using idr.
216 */
217 again:
218 /* ensure there is space available to allocate a handle */
219 if (idr_pre_get(&file_priv->object_idr, GFP_KERNEL) == 0)
220 return -ENOMEM;
221
222 /* do the allocation under our spinlock */
223 spin_lock(&file_priv->table_lock);
224 ret = idr_get_new_above(&file_priv->object_idr, obj, 1, handlep);
225 spin_unlock(&file_priv->table_lock);
226 if (ret == -EAGAIN)
227 goto again;
228
229 if (ret != 0)
230 return ret;
231
232 drm_gem_object_handle_reference(obj);
233 return 0;
234 }
235 EXPORT_SYMBOL(drm_gem_handle_create);
236
237 /** Returns a reference to the object named by the handle. */
238 struct drm_gem_object *
239 drm_gem_object_lookup(struct drm_device *dev, struct drm_file *filp,
240 int handle)
241 {
242 struct drm_gem_object *obj;
243
244 spin_lock(&filp->table_lock);
245
246 /* Check if we currently have a reference on the object */
247 obj = idr_find(&filp->object_idr, handle);
248 if (obj == NULL) {
249 spin_unlock(&filp->table_lock);
250 return NULL;
251 }
252
253 drm_gem_object_reference(obj);
254
255 spin_unlock(&filp->table_lock);
256
257 return obj;
258 }
259 EXPORT_SYMBOL(drm_gem_object_lookup);
260
261 /**
262 * Releases the handle to an mm object.
263 */
264 int
265 drm_gem_close_ioctl(struct drm_device *dev, void *data,
266 struct drm_file *file_priv)
267 {
268 struct drm_gem_close *args = data;
269 int ret;
270
271 if (!(dev->driver->driver_features & DRIVER_GEM))
272 return -ENODEV;
273
274 ret = drm_gem_handle_delete(file_priv, args->handle);
275
276 return ret;
277 }
278
279 /**
280 * Create a global name for an object, returning the name.
281 *
282 * Note that the name does not hold a reference; when the object
283 * is freed, the name goes away.
284 */
285 int
286 drm_gem_flink_ioctl(struct drm_device *dev, void *data,
287 struct drm_file *file_priv)
288 {
289 struct drm_gem_flink *args = data;
290 struct drm_gem_object *obj;
291 int ret;
292
293 if (!(dev->driver->driver_features & DRIVER_GEM))
294 return -ENODEV;
295
296 obj = drm_gem_object_lookup(dev, file_priv, args->handle);
297 if (obj == NULL)
298 return -EBADF;
299
300 again:
301 if (idr_pre_get(&dev->object_name_idr, GFP_KERNEL) == 0) {
302 ret = -ENOMEM;
303 goto err;
304 }
305
306 spin_lock(&dev->object_name_lock);
307 if (!obj->name) {
308 ret = idr_get_new_above(&dev->object_name_idr, obj, 1,
309 &obj->name);
310 args->name = (uint64_t) obj->name;
311 spin_unlock(&dev->object_name_lock);
312
313 if (ret == -EAGAIN)
314 goto again;
315
316 if (ret != 0)
317 goto err;
318
319 /* Allocate a reference for the name table. */
320 drm_gem_object_reference(obj);
321 } else {
322 args->name = (uint64_t) obj->name;
323 spin_unlock(&dev->object_name_lock);
324 ret = 0;
325 }
326
327 err:
328 mutex_lock(&dev->struct_mutex);
329 drm_gem_object_unreference(obj);
330 mutex_unlock(&dev->struct_mutex);
331 return ret;
332 }
333
334 /**
335 * Open an object using the global name, returning a handle and the size.
336 *
337 * This handle (of course) holds a reference to the object, so the object
338 * will not go away until the handle is deleted.
339 */
340 int
341 drm_gem_open_ioctl(struct drm_device *dev, void *data,
342 struct drm_file *file_priv)
343 {
344 struct drm_gem_open *args = data;
345 struct drm_gem_object *obj;
346 int ret;
347 int handle;
348
349 if (!(dev->driver->driver_features & DRIVER_GEM))
350 return -ENODEV;
351
352 spin_lock(&dev->object_name_lock);
353 obj = idr_find(&dev->object_name_idr, (int) args->name);
354 if (obj)
355 drm_gem_object_reference(obj);
356 spin_unlock(&dev->object_name_lock);
357 if (!obj)
358 return -ENOENT;
359
360 ret = drm_gem_handle_create(file_priv, obj, &handle);
361 mutex_lock(&dev->struct_mutex);
362 drm_gem_object_unreference(obj);
363 mutex_unlock(&dev->struct_mutex);
364 if (ret)
365 return ret;
366
367 args->handle = handle;
368 args->size = obj->size;
369
370 return 0;
371 }
372
373 /**
374 * Called at device open time, sets up the structure for handling refcounting
375 * of mm objects.
376 */
377 void
378 drm_gem_open(struct drm_device *dev, struct drm_file *file_private)
379 {
380 idr_init(&file_private->object_idr);
381 spin_lock_init(&file_private->table_lock);
382 }
383
384 /**
385 * Called at device close to release the file's
386 * handle references on objects.
387 */
388 static int
389 drm_gem_object_release_handle(int id, void *ptr, void *data)
390 {
391 struct drm_gem_object *obj = ptr;
392
393 drm_gem_object_handle_unreference(obj);
394
395 return 0;
396 }
397
398 /**
399 * Called at close time when the filp is going away.
400 *
401 * Releases any remaining references on objects by this filp.
402 */
403 void
404 drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
405 {
406 mutex_lock(&dev->struct_mutex);
407 idr_for_each(&file_private->object_idr,
408 &drm_gem_object_release_handle, NULL);
409
410 idr_destroy(&file_private->object_idr);
411 mutex_unlock(&dev->struct_mutex);
412 }
413
414 /**
415 * Called after the last reference to the object has been lost.
416 *
417 * Frees the object
418 */
419 void
420 drm_gem_object_free(struct kref *kref)
421 {
422 struct drm_gem_object *obj = (struct drm_gem_object *) kref;
423 struct drm_device *dev = obj->dev;
424
425 BUG_ON(!mutex_is_locked(&dev->struct_mutex));
426
427 if (dev->driver->gem_free_object != NULL)
428 dev->driver->gem_free_object(obj);
429
430 fput(obj->filp);
431 atomic_dec(&dev->object_count);
432 atomic_sub(obj->size, &dev->object_memory);
433 kfree(obj);
434 }
435 EXPORT_SYMBOL(drm_gem_object_free);
436
437 /**
438 * Called after the last handle to the object has been closed
439 *
440 * Removes any name for the object. Note that this must be
441 * called before drm_gem_object_free or we'll be touching
442 * freed memory
443 */
444 void
445 drm_gem_object_handle_free(struct kref *kref)
446 {
447 struct drm_gem_object *obj = container_of(kref,
448 struct drm_gem_object,
449 handlecount);
450 struct drm_device *dev = obj->dev;
451
452 /* Remove any name for this object */
453 spin_lock(&dev->object_name_lock);
454 if (obj->name) {
455 idr_remove(&dev->object_name_idr, obj->name);
456 obj->name = 0;
457 spin_unlock(&dev->object_name_lock);
458 /*
459 * The object name held a reference to this object, drop
460 * that now.
461 */
462 drm_gem_object_unreference(obj);
463 } else
464 spin_unlock(&dev->object_name_lock);
465
466 }
467 EXPORT_SYMBOL(drm_gem_object_handle_free);
468
469 void drm_gem_vm_open(struct vm_area_struct *vma)
470 {
471 struct drm_gem_object *obj = vma->vm_private_data;
472
473 drm_gem_object_reference(obj);
474 }
475 EXPORT_SYMBOL(drm_gem_vm_open);
476
477 void drm_gem_vm_close(struct vm_area_struct *vma)
478 {
479 struct drm_gem_object *obj = vma->vm_private_data;
480 struct drm_device *dev = obj->dev;
481
482 mutex_lock(&dev->struct_mutex);
483 drm_gem_object_unreference(obj);
484 mutex_unlock(&dev->struct_mutex);
485 }
486 EXPORT_SYMBOL(drm_gem_vm_close);
487
488
489 /**
490 * drm_gem_mmap - memory map routine for GEM objects
491 * @filp: DRM file pointer
492 * @vma: VMA for the area to be mapped
493 *
494 * If a driver supports GEM object mapping, mmap calls on the DRM file
495 * descriptor will end up here.
496 *
497 * If we find the object based on the offset passed in (vma->vm_pgoff will
498 * contain the fake offset we created when the GTT map ioctl was called on
499 * the object), we set up the driver fault handler so that any accesses
500 * to the object can be trapped, to perform migration, GTT binding, surface
501 * register allocation, or performance monitoring.
502 */
503 int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
504 {
505 struct drm_file *priv = filp->private_data;
506 struct drm_device *dev = priv->minor->dev;
507 struct drm_gem_mm *mm = dev->mm_private;
508 struct drm_local_map *map = NULL;
509 struct drm_gem_object *obj;
510 struct drm_hash_item *hash;
511 int ret = 0;
512
513 mutex_lock(&dev->struct_mutex);
514
515 if (drm_ht_find_item(&mm->offset_hash, vma->vm_pgoff, &hash)) {
516 mutex_unlock(&dev->struct_mutex);
517 return drm_mmap(filp, vma);
518 }
519
520 map = drm_hash_entry(hash, struct drm_map_list, hash)->map;
521 if (!map ||
522 ((map->flags & _DRM_RESTRICTED) && !capable(CAP_SYS_ADMIN))) {
523 ret = -EPERM;
524 goto out_unlock;
525 }
526
527 /* Check for valid size. */
528 if (map->size < vma->vm_end - vma->vm_start) {
529 ret = -EINVAL;
530 goto out_unlock;
531 }
532
533 obj = map->handle;
534 if (!obj->dev->driver->gem_vm_ops) {
535 ret = -EINVAL;
536 goto out_unlock;
537 }
538
539 vma->vm_flags |= VM_RESERVED | VM_IO | VM_PFNMAP | VM_DONTEXPAND;
540 vma->vm_ops = obj->dev->driver->gem_vm_ops;
541 vma->vm_private_data = map->handle;
542 /* FIXME: use pgprot_writecombine when available */
543 vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
544
545 /* Take a ref for this mapping of the object, so that the fault
546 * handler can dereference the mmap offset's pointer to the object.
547 * This reference is cleaned up by the corresponding vm_close
548 * (which should happen whether the vma was created by this call, or
549 * by a vm_open due to mremap or partial unmap or whatever).
550 */
551 drm_gem_object_reference(obj);
552
553 vma->vm_file = filp; /* Needed for drm_vm_open() */
554 drm_vm_open_locked(vma);
555
556 out_unlock:
557 mutex_unlock(&dev->struct_mutex);
558
559 return ret;
560 }
561 EXPORT_SYMBOL(drm_gem_mmap);
562
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