1 /*
2 * Legacy: Generic DRM Contexts
3 *
4 * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
5 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
6 * All Rights Reserved.
7 *
8 * Author: Rickard E. (Rik) Faith <faith@valinux.com>
9 * Author: Gareth Hughes <gareth@valinux.com>
10 *
11 * Permission is hereby granted, free of charge, to any person obtaining a
12 * copy of this software and associated documentation files (the "Software"),
13 * to deal in the Software without restriction, including without limitation
14 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
15 * and/or sell copies of the Software, and to permit persons to whom the
16 * Software is furnished to do so, subject to the following conditions:
17 *
18 * The above copyright notice and this permission notice (including the next
19 * paragraph) shall be included in all copies or substantial portions of the
20 * Software.
21 *
22 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
23 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
25 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
26 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
27 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
28 * OTHER DEALINGS IN THE SOFTWARE.
29 */
30
31 #include <linux/slab.h>
32 #include <linux/uaccess.h>
33
34 #include <drm/drm_drv.h>
35 #include <drm/drm_file.h>
36 #include <drm/drm_print.h>
37
38 #include "drm_legacy.h"
39
40 struct drm_ctx_list {
41 struct list_head head;
42 drm_context_t handle;
43 struct drm_file *tag;
44 };
45
46 /******************************************************************/
47 /** \name Context bitmap support */
48 /*@{*/
49
50 /*
51 * Free a handle from the context bitmap.
52 *
53 * \param dev DRM device.
54 * \param ctx_handle context handle.
55 *
56 * Clears the bit specified by \p ctx_handle in drm_device::ctx_bitmap and the entry
57 * in drm_device::ctx_idr, while holding the drm_device::struct_mutex
58 * lock.
59 */
drm_legacy_ctxbitmap_free(struct drm_device * dev,int ctx_handle)60 void drm_legacy_ctxbitmap_free(struct drm_device * dev, int ctx_handle)
61 {
62 if (!drm_core_check_feature(dev, DRIVER_LEGACY))
63 return;
64
65 mutex_lock(&dev->struct_mutex);
66 idr_remove(&dev->ctx_idr, ctx_handle);
67 mutex_unlock(&dev->struct_mutex);
68 }
69
70 /*
71 * Context bitmap allocation.
72 *
73 * \param dev DRM device.
74 * \return (non-negative) context handle on success or a negative number on failure.
75 *
76 * Allocate a new idr from drm_device::ctx_idr while holding the
77 * drm_device::struct_mutex lock.
78 */
drm_legacy_ctxbitmap_next(struct drm_device * dev)79 static int drm_legacy_ctxbitmap_next(struct drm_device * dev)
80 {
81 int ret;
82
83 mutex_lock(&dev->struct_mutex);
84 ret = idr_alloc(&dev->ctx_idr, NULL, DRM_RESERVED_CONTEXTS, 0,
85 GFP_KERNEL);
86 mutex_unlock(&dev->struct_mutex);
87 return ret;
88 }
89
90 /*
91 * Context bitmap initialization.
92 *
93 * \param dev DRM device.
94 *
95 * Initialise the drm_device::ctx_idr
96 */
drm_legacy_ctxbitmap_init(struct drm_device * dev)97 void drm_legacy_ctxbitmap_init(struct drm_device * dev)
98 {
99 if (!drm_core_check_feature(dev, DRIVER_LEGACY))
100 return;
101
102 idr_init(&dev->ctx_idr);
103 }
104
105 /*
106 * Context bitmap cleanup.
107 *
108 * \param dev DRM device.
109 *
110 * Free all idr members using drm_ctx_sarea_free helper function
111 * while holding the drm_device::struct_mutex lock.
112 */
drm_legacy_ctxbitmap_cleanup(struct drm_device * dev)113 void drm_legacy_ctxbitmap_cleanup(struct drm_device * dev)
114 {
115 if (!drm_core_check_feature(dev, DRIVER_LEGACY))
116 return;
117
118 mutex_lock(&dev->struct_mutex);
119 idr_destroy(&dev->ctx_idr);
120 mutex_unlock(&dev->struct_mutex);
121 }
122
123 /**
124 * drm_legacy_ctxbitmap_flush() - Flush all contexts owned by a file
125 * @dev: DRM device to operate on
126 * @file: Open file to flush contexts for
127 *
128 * This iterates over all contexts on @dev and drops them if they're owned by
129 * @file. Note that after this call returns, new contexts might be added if
130 * the file is still alive.
131 */
drm_legacy_ctxbitmap_flush(struct drm_device * dev,struct drm_file * file)132 void drm_legacy_ctxbitmap_flush(struct drm_device *dev, struct drm_file *file)
133 {
134 struct drm_ctx_list *pos, *tmp;
135
136 if (!drm_core_check_feature(dev, DRIVER_LEGACY))
137 return;
138
139 mutex_lock(&dev->ctxlist_mutex);
140
141 list_for_each_entry_safe(pos, tmp, &dev->ctxlist, head) {
142 if (pos->tag == file &&
143 pos->handle != DRM_KERNEL_CONTEXT) {
144 if (dev->driver->context_dtor)
145 dev->driver->context_dtor(dev, pos->handle);
146
147 drm_legacy_ctxbitmap_free(dev, pos->handle);
148 list_del(&pos->head);
149 kfree(pos);
150 }
151 }
152
153 mutex_unlock(&dev->ctxlist_mutex);
154 }
155
156 /*@}*/
157
158 /******************************************************************/
159 /** \name Per Context SAREA Support */
160 /*@{*/
161
162 /*
163 * Get per-context SAREA.
164 *
165 * \param inode device inode.
166 * \param file_priv DRM file private.
167 * \param cmd command.
168 * \param arg user argument pointing to a drm_ctx_priv_map structure.
169 * \return zero on success or a negative number on failure.
170 *
171 * Gets the map from drm_device::ctx_idr with the handle specified and
172 * returns its handle.
173 */
drm_legacy_getsareactx(struct drm_device * dev,void * data,struct drm_file * file_priv)174 int drm_legacy_getsareactx(struct drm_device *dev, void *data,
175 struct drm_file *file_priv)
176 {
177 struct drm_ctx_priv_map *request = data;
178 struct drm_local_map *map;
179 struct drm_map_list *_entry;
180
181 if (!drm_core_check_feature(dev, DRIVER_LEGACY))
182 return -EOPNOTSUPP;
183
184 mutex_lock(&dev->struct_mutex);
185
186 map = idr_find(&dev->ctx_idr, request->ctx_id);
187 if (!map) {
188 mutex_unlock(&dev->struct_mutex);
189 return -EINVAL;
190 }
191
192 request->handle = NULL;
193 list_for_each_entry(_entry, &dev->maplist, head) {
194 if (_entry->map == map) {
195 request->handle =
196 (void *)(unsigned long)_entry->user_token;
197 break;
198 }
199 }
200
201 mutex_unlock(&dev->struct_mutex);
202
203 if (request->handle == NULL)
204 return -EINVAL;
205
206 return 0;
207 }
208
209 /*
210 * Set per-context SAREA.
211 *
212 * \param inode device inode.
213 * \param file_priv DRM file private.
214 * \param cmd command.
215 * \param arg user argument pointing to a drm_ctx_priv_map structure.
216 * \return zero on success or a negative number on failure.
217 *
218 * Searches the mapping specified in \p arg and update the entry in
219 * drm_device::ctx_idr with it.
220 */
drm_legacy_setsareactx(struct drm_device * dev,void * data,struct drm_file * file_priv)221 int drm_legacy_setsareactx(struct drm_device *dev, void *data,
222 struct drm_file *file_priv)
223 {
224 struct drm_ctx_priv_map *request = data;
225 struct drm_local_map *map = NULL;
226 struct drm_map_list *r_list = NULL;
227
228 if (!drm_core_check_feature(dev, DRIVER_LEGACY))
229 return -EOPNOTSUPP;
230
231 mutex_lock(&dev->struct_mutex);
232 list_for_each_entry(r_list, &dev->maplist, head) {
233 if (r_list->map
234 && r_list->user_token == (unsigned long) request->handle)
235 goto found;
236 }
237 bad:
238 mutex_unlock(&dev->struct_mutex);
239 return -EINVAL;
240
241 found:
242 map = r_list->map;
243 if (!map)
244 goto bad;
245
246 if (IS_ERR(idr_replace(&dev->ctx_idr, map, request->ctx_id)))
247 goto bad;
248
249 mutex_unlock(&dev->struct_mutex);
250
251 return 0;
252 }
253
254 /*@}*/
255
256 /******************************************************************/
257 /** \name The actual DRM context handling routines */
258 /*@{*/
259
260 /*
261 * Switch context.
262 *
263 * \param dev DRM device.
264 * \param old old context handle.
265 * \param new new context handle.
266 * \return zero on success or a negative number on failure.
267 *
268 * Attempt to set drm_device::context_flag.
269 */
drm_context_switch(struct drm_device * dev,int old,int new)270 static int drm_context_switch(struct drm_device * dev, int old, int new)
271 {
272 if (test_and_set_bit(0, &dev->context_flag)) {
273 DRM_ERROR("Reentering -- FIXME\n");
274 return -EBUSY;
275 }
276
277 DRM_DEBUG("Context switch from %d to %d\n", old, new);
278
279 if (new == dev->last_context) {
280 clear_bit(0, &dev->context_flag);
281 return 0;
282 }
283
284 return 0;
285 }
286
287 /*
288 * Complete context switch.
289 *
290 * \param dev DRM device.
291 * \param new new context handle.
292 * \return zero on success or a negative number on failure.
293 *
294 * Updates drm_device::last_context and drm_device::last_switch. Verifies the
295 * hardware lock is held, clears the drm_device::context_flag and wakes up
296 * drm_device::context_wait.
297 */
drm_context_switch_complete(struct drm_device * dev,struct drm_file * file_priv,int new)298 static int drm_context_switch_complete(struct drm_device *dev,
299 struct drm_file *file_priv, int new)
300 {
301 dev->last_context = new; /* PRE/POST: This is the _only_ writer. */
302
303 if (!_DRM_LOCK_IS_HELD(file_priv->master->lock.hw_lock->lock)) {
304 DRM_ERROR("Lock isn't held after context switch\n");
305 }
306
307 /* If a context switch is ever initiated
308 when the kernel holds the lock, release
309 that lock here.
310 */
311 clear_bit(0, &dev->context_flag);
312
313 return 0;
314 }
315
316 /*
317 * Reserve contexts.
318 *
319 * \param inode device inode.
320 * \param file_priv DRM file private.
321 * \param cmd command.
322 * \param arg user argument pointing to a drm_ctx_res structure.
323 * \return zero on success or a negative number on failure.
324 */
drm_legacy_resctx(struct drm_device * dev,void * data,struct drm_file * file_priv)325 int drm_legacy_resctx(struct drm_device *dev, void *data,
326 struct drm_file *file_priv)
327 {
328 struct drm_ctx_res *res = data;
329 struct drm_ctx ctx;
330 int i;
331
332 if (!drm_core_check_feature(dev, DRIVER_LEGACY))
333 return -EOPNOTSUPP;
334
335 if (res->count >= DRM_RESERVED_CONTEXTS) {
336 memset(&ctx, 0, sizeof(ctx));
337 for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
338 ctx.handle = i;
339 if (copy_to_user(&res->contexts[i], &ctx, sizeof(ctx)))
340 return -EFAULT;
341 }
342 }
343 res->count = DRM_RESERVED_CONTEXTS;
344
345 return 0;
346 }
347
348 /*
349 * Add context.
350 *
351 * \param inode device inode.
352 * \param file_priv DRM file private.
353 * \param cmd command.
354 * \param arg user argument pointing to a drm_ctx structure.
355 * \return zero on success or a negative number on failure.
356 *
357 * Get a new handle for the context and copy to userspace.
358 */
drm_legacy_addctx(struct drm_device * dev,void * data,struct drm_file * file_priv)359 int drm_legacy_addctx(struct drm_device *dev, void *data,
360 struct drm_file *file_priv)
361 {
362 struct drm_ctx_list *ctx_entry;
363 struct drm_ctx *ctx = data;
364 int tmp_handle;
365
366 if (!drm_core_check_feature(dev, DRIVER_LEGACY))
367 return -EOPNOTSUPP;
368
369 tmp_handle = drm_legacy_ctxbitmap_next(dev);
370 if (tmp_handle == DRM_KERNEL_CONTEXT) {
371 /* Skip kernel's context and get a new one. */
372 tmp_handle = drm_legacy_ctxbitmap_next(dev);
373 }
374 DRM_DEBUG("%d\n", tmp_handle);
375 if (tmp_handle < 0) {
376 DRM_DEBUG("Not enough free contexts.\n");
377 /* Should this return -EBUSY instead? */
378 return tmp_handle;
379 }
380
381 ctx->handle = tmp_handle;
382
383 ctx_entry = kmalloc(sizeof(*ctx_entry), GFP_KERNEL);
384 if (!ctx_entry) {
385 DRM_DEBUG("out of memory\n");
386 return -ENOMEM;
387 }
388
389 INIT_LIST_HEAD(&ctx_entry->head);
390 ctx_entry->handle = ctx->handle;
391 ctx_entry->tag = file_priv;
392
393 mutex_lock(&dev->ctxlist_mutex);
394 list_add(&ctx_entry->head, &dev->ctxlist);
395 mutex_unlock(&dev->ctxlist_mutex);
396
397 return 0;
398 }
399
400 /*
401 * Get context.
402 *
403 * \param inode device inode.
404 * \param file_priv DRM file private.
405 * \param cmd command.
406 * \param arg user argument pointing to a drm_ctx structure.
407 * \return zero on success or a negative number on failure.
408 */
drm_legacy_getctx(struct drm_device * dev,void * data,struct drm_file * file_priv)409 int drm_legacy_getctx(struct drm_device *dev, void *data,
410 struct drm_file *file_priv)
411 {
412 struct drm_ctx *ctx = data;
413
414 if (!drm_core_check_feature(dev, DRIVER_LEGACY))
415 return -EOPNOTSUPP;
416
417 /* This is 0, because we don't handle any context flags */
418 ctx->flags = 0;
419
420 return 0;
421 }
422
423 /*
424 * Switch context.
425 *
426 * \param inode device inode.
427 * \param file_priv DRM file private.
428 * \param cmd command.
429 * \param arg user argument pointing to a drm_ctx structure.
430 * \return zero on success or a negative number on failure.
431 *
432 * Calls context_switch().
433 */
drm_legacy_switchctx(struct drm_device * dev,void * data,struct drm_file * file_priv)434 int drm_legacy_switchctx(struct drm_device *dev, void *data,
435 struct drm_file *file_priv)
436 {
437 struct drm_ctx *ctx = data;
438
439 if (!drm_core_check_feature(dev, DRIVER_LEGACY))
440 return -EOPNOTSUPP;
441
442 DRM_DEBUG("%d\n", ctx->handle);
443 return drm_context_switch(dev, dev->last_context, ctx->handle);
444 }
445
446 /*
447 * New context.
448 *
449 * \param inode device inode.
450 * \param file_priv DRM file private.
451 * \param cmd command.
452 * \param arg user argument pointing to a drm_ctx structure.
453 * \return zero on success or a negative number on failure.
454 *
455 * Calls context_switch_complete().
456 */
drm_legacy_newctx(struct drm_device * dev,void * data,struct drm_file * file_priv)457 int drm_legacy_newctx(struct drm_device *dev, void *data,
458 struct drm_file *file_priv)
459 {
460 struct drm_ctx *ctx = data;
461
462 if (!drm_core_check_feature(dev, DRIVER_LEGACY))
463 return -EOPNOTSUPP;
464
465 DRM_DEBUG("%d\n", ctx->handle);
466 drm_context_switch_complete(dev, file_priv, ctx->handle);
467
468 return 0;
469 }
470
471 /*
472 * Remove context.
473 *
474 * \param inode device inode.
475 * \param file_priv DRM file private.
476 * \param cmd command.
477 * \param arg user argument pointing to a drm_ctx structure.
478 * \return zero on success or a negative number on failure.
479 *
480 * If not the special kernel context, calls ctxbitmap_free() to free the specified context.
481 */
drm_legacy_rmctx(struct drm_device * dev,void * data,struct drm_file * file_priv)482 int drm_legacy_rmctx(struct drm_device *dev, void *data,
483 struct drm_file *file_priv)
484 {
485 struct drm_ctx *ctx = data;
486
487 if (!drm_core_check_feature(dev, DRIVER_LEGACY))
488 return -EOPNOTSUPP;
489
490 DRM_DEBUG("%d\n", ctx->handle);
491 if (ctx->handle != DRM_KERNEL_CONTEXT) {
492 if (dev->driver->context_dtor)
493 dev->driver->context_dtor(dev, ctx->handle);
494 drm_legacy_ctxbitmap_free(dev, ctx->handle);
495 }
496
497 mutex_lock(&dev->ctxlist_mutex);
498 if (!list_empty(&dev->ctxlist)) {
499 struct drm_ctx_list *pos, *n;
500
501 list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
502 if (pos->handle == ctx->handle) {
503 list_del(&pos->head);
504 kfree(pos);
505 }
506 }
507 }
508 mutex_unlock(&dev->ctxlist_mutex);
509
510 return 0;
511 }
512
513 /*@}*/
514