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_KMS_LEGACY_CONTEXT) &&
63 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
64 		return;
65 
66 	mutex_lock(&dev->struct_mutex);
67 	idr_remove(&dev->ctx_idr, ctx_handle);
68 	mutex_unlock(&dev->struct_mutex);
69 }
70 
71 /*
72  * Context bitmap allocation.
73  *
74  * \param dev DRM device.
75  * \return (non-negative) context handle on success or a negative number on failure.
76  *
77  * Allocate a new idr from drm_device::ctx_idr while holding the
78  * drm_device::struct_mutex lock.
79  */
drm_legacy_ctxbitmap_next(struct drm_device * dev)80 static int drm_legacy_ctxbitmap_next(struct drm_device * dev)
81 {
82 	int ret;
83 
84 	mutex_lock(&dev->struct_mutex);
85 	ret = idr_alloc(&dev->ctx_idr, NULL, DRM_RESERVED_CONTEXTS, 0,
86 			GFP_KERNEL);
87 	mutex_unlock(&dev->struct_mutex);
88 	return ret;
89 }
90 
91 /*
92  * Context bitmap initialization.
93  *
94  * \param dev DRM device.
95  *
96  * Initialise the drm_device::ctx_idr
97  */
drm_legacy_ctxbitmap_init(struct drm_device * dev)98 void drm_legacy_ctxbitmap_init(struct drm_device * dev)
99 {
100 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
101 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
102 		return;
103 
104 	idr_init(&dev->ctx_idr);
105 }
106 
107 /*
108  * Context bitmap cleanup.
109  *
110  * \param dev DRM device.
111  *
112  * Free all idr members using drm_ctx_sarea_free helper function
113  * while holding the drm_device::struct_mutex lock.
114  */
drm_legacy_ctxbitmap_cleanup(struct drm_device * dev)115 void drm_legacy_ctxbitmap_cleanup(struct drm_device * dev)
116 {
117 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
118 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
119 		return;
120 
121 	mutex_lock(&dev->struct_mutex);
122 	idr_destroy(&dev->ctx_idr);
123 	mutex_unlock(&dev->struct_mutex);
124 }
125 
126 /**
127  * drm_legacy_ctxbitmap_flush() - Flush all contexts owned by a file
128  * @dev: DRM device to operate on
129  * @file: Open file to flush contexts for
130  *
131  * This iterates over all contexts on @dev and drops them if they're owned by
132  * @file. Note that after this call returns, new contexts might be added if
133  * the file is still alive.
134  */
drm_legacy_ctxbitmap_flush(struct drm_device * dev,struct drm_file * file)135 void drm_legacy_ctxbitmap_flush(struct drm_device *dev, struct drm_file *file)
136 {
137 	struct drm_ctx_list *pos, *tmp;
138 
139 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
140 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
141 		return;
142 
143 	mutex_lock(&dev->ctxlist_mutex);
144 
145 	list_for_each_entry_safe(pos, tmp, &dev->ctxlist, head) {
146 		if (pos->tag == file &&
147 		    pos->handle != DRM_KERNEL_CONTEXT) {
148 			if (dev->driver->context_dtor)
149 				dev->driver->context_dtor(dev, pos->handle);
150 
151 			drm_legacy_ctxbitmap_free(dev, pos->handle);
152 			list_del(&pos->head);
153 			kfree(pos);
154 		}
155 	}
156 
157 	mutex_unlock(&dev->ctxlist_mutex);
158 }
159 
160 /*@}*/
161 
162 /******************************************************************/
163 /** \name Per Context SAREA Support */
164 /*@{*/
165 
166 /*
167  * Get per-context SAREA.
168  *
169  * \param inode device inode.
170  * \param file_priv DRM file private.
171  * \param cmd command.
172  * \param arg user argument pointing to a drm_ctx_priv_map structure.
173  * \return zero on success or a negative number on failure.
174  *
175  * Gets the map from drm_device::ctx_idr with the handle specified and
176  * returns its handle.
177  */
drm_legacy_getsareactx(struct drm_device * dev,void * data,struct drm_file * file_priv)178 int drm_legacy_getsareactx(struct drm_device *dev, void *data,
179 			   struct drm_file *file_priv)
180 {
181 	struct drm_ctx_priv_map *request = data;
182 	struct drm_local_map *map;
183 	struct drm_map_list *_entry;
184 
185 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
186 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
187 		return -EOPNOTSUPP;
188 
189 	mutex_lock(&dev->struct_mutex);
190 
191 	map = idr_find(&dev->ctx_idr, request->ctx_id);
192 	if (!map) {
193 		mutex_unlock(&dev->struct_mutex);
194 		return -EINVAL;
195 	}
196 
197 	request->handle = NULL;
198 	list_for_each_entry(_entry, &dev->maplist, head) {
199 		if (_entry->map == map) {
200 			request->handle =
201 			    (void *)(unsigned long)_entry->user_token;
202 			break;
203 		}
204 	}
205 
206 	mutex_unlock(&dev->struct_mutex);
207 
208 	if (request->handle == NULL)
209 		return -EINVAL;
210 
211 	return 0;
212 }
213 
214 /*
215  * Set per-context SAREA.
216  *
217  * \param inode device inode.
218  * \param file_priv DRM file private.
219  * \param cmd command.
220  * \param arg user argument pointing to a drm_ctx_priv_map structure.
221  * \return zero on success or a negative number on failure.
222  *
223  * Searches the mapping specified in \p arg and update the entry in
224  * drm_device::ctx_idr with it.
225  */
drm_legacy_setsareactx(struct drm_device * dev,void * data,struct drm_file * file_priv)226 int drm_legacy_setsareactx(struct drm_device *dev, void *data,
227 			   struct drm_file *file_priv)
228 {
229 	struct drm_ctx_priv_map *request = data;
230 	struct drm_local_map *map = NULL;
231 	struct drm_map_list *r_list = NULL;
232 
233 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
234 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
235 		return -EOPNOTSUPP;
236 
237 	mutex_lock(&dev->struct_mutex);
238 	list_for_each_entry(r_list, &dev->maplist, head) {
239 		if (r_list->map
240 		    && r_list->user_token == (unsigned long) request->handle)
241 			goto found;
242 	}
243       bad:
244 	mutex_unlock(&dev->struct_mutex);
245 	return -EINVAL;
246 
247       found:
248 	map = r_list->map;
249 	if (!map)
250 		goto bad;
251 
252 	if (IS_ERR(idr_replace(&dev->ctx_idr, map, request->ctx_id)))
253 		goto bad;
254 
255 	mutex_unlock(&dev->struct_mutex);
256 
257 	return 0;
258 }
259 
260 /*@}*/
261 
262 /******************************************************************/
263 /** \name The actual DRM context handling routines */
264 /*@{*/
265 
266 /*
267  * Switch context.
268  *
269  * \param dev DRM device.
270  * \param old old context handle.
271  * \param new new context handle.
272  * \return zero on success or a negative number on failure.
273  *
274  * Attempt to set drm_device::context_flag.
275  */
drm_context_switch(struct drm_device * dev,int old,int new)276 static int drm_context_switch(struct drm_device * dev, int old, int new)
277 {
278 	if (test_and_set_bit(0, &dev->context_flag)) {
279 		DRM_ERROR("Reentering -- FIXME\n");
280 		return -EBUSY;
281 	}
282 
283 	DRM_DEBUG("Context switch from %d to %d\n", old, new);
284 
285 	if (new == dev->last_context) {
286 		clear_bit(0, &dev->context_flag);
287 		return 0;
288 	}
289 
290 	return 0;
291 }
292 
293 /*
294  * Complete context switch.
295  *
296  * \param dev DRM device.
297  * \param new new context handle.
298  * \return zero on success or a negative number on failure.
299  *
300  * Updates drm_device::last_context and drm_device::last_switch. Verifies the
301  * hardware lock is held, clears the drm_device::context_flag and wakes up
302  * drm_device::context_wait.
303  */
drm_context_switch_complete(struct drm_device * dev,struct drm_file * file_priv,int new)304 static int drm_context_switch_complete(struct drm_device *dev,
305 				       struct drm_file *file_priv, int new)
306 {
307 	dev->last_context = new;	/* PRE/POST: This is the _only_ writer. */
308 
309 	if (!_DRM_LOCK_IS_HELD(file_priv->master->lock.hw_lock->lock)) {
310 		DRM_ERROR("Lock isn't held after context switch\n");
311 	}
312 
313 	/* If a context switch is ever initiated
314 	   when the kernel holds the lock, release
315 	   that lock here.
316 	 */
317 	clear_bit(0, &dev->context_flag);
318 
319 	return 0;
320 }
321 
322 /*
323  * Reserve contexts.
324  *
325  * \param inode device inode.
326  * \param file_priv DRM file private.
327  * \param cmd command.
328  * \param arg user argument pointing to a drm_ctx_res structure.
329  * \return zero on success or a negative number on failure.
330  */
drm_legacy_resctx(struct drm_device * dev,void * data,struct drm_file * file_priv)331 int drm_legacy_resctx(struct drm_device *dev, void *data,
332 		      struct drm_file *file_priv)
333 {
334 	struct drm_ctx_res *res = data;
335 	struct drm_ctx ctx;
336 	int i;
337 
338 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
339 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
340 		return -EOPNOTSUPP;
341 
342 	if (res->count >= DRM_RESERVED_CONTEXTS) {
343 		memset(&ctx, 0, sizeof(ctx));
344 		for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
345 			ctx.handle = i;
346 			if (copy_to_user(&res->contexts[i], &ctx, sizeof(ctx)))
347 				return -EFAULT;
348 		}
349 	}
350 	res->count = DRM_RESERVED_CONTEXTS;
351 
352 	return 0;
353 }
354 
355 /*
356  * Add context.
357  *
358  * \param inode device inode.
359  * \param file_priv DRM file private.
360  * \param cmd command.
361  * \param arg user argument pointing to a drm_ctx structure.
362  * \return zero on success or a negative number on failure.
363  *
364  * Get a new handle for the context and copy to userspace.
365  */
drm_legacy_addctx(struct drm_device * dev,void * data,struct drm_file * file_priv)366 int drm_legacy_addctx(struct drm_device *dev, void *data,
367 		      struct drm_file *file_priv)
368 {
369 	struct drm_ctx_list *ctx_entry;
370 	struct drm_ctx *ctx = data;
371 	int tmp_handle;
372 
373 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
374 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
375 		return -EOPNOTSUPP;
376 
377 	tmp_handle = drm_legacy_ctxbitmap_next(dev);
378 	if (tmp_handle == DRM_KERNEL_CONTEXT) {
379 		/* Skip kernel's context and get a new one. */
380 		tmp_handle = drm_legacy_ctxbitmap_next(dev);
381 	}
382 	DRM_DEBUG("%d\n", tmp_handle);
383 	if (tmp_handle < 0) {
384 		DRM_DEBUG("Not enough free contexts.\n");
385 		/* Should this return -EBUSY instead? */
386 		return tmp_handle;
387 	}
388 
389 	ctx->handle = tmp_handle;
390 
391 	ctx_entry = kmalloc(sizeof(*ctx_entry), GFP_KERNEL);
392 	if (!ctx_entry) {
393 		DRM_DEBUG("out of memory\n");
394 		return -ENOMEM;
395 	}
396 
397 	INIT_LIST_HEAD(&ctx_entry->head);
398 	ctx_entry->handle = ctx->handle;
399 	ctx_entry->tag = file_priv;
400 
401 	mutex_lock(&dev->ctxlist_mutex);
402 	list_add(&ctx_entry->head, &dev->ctxlist);
403 	mutex_unlock(&dev->ctxlist_mutex);
404 
405 	return 0;
406 }
407 
408 /*
409  * Get context.
410  *
411  * \param inode device inode.
412  * \param file_priv DRM file private.
413  * \param cmd command.
414  * \param arg user argument pointing to a drm_ctx structure.
415  * \return zero on success or a negative number on failure.
416  */
drm_legacy_getctx(struct drm_device * dev,void * data,struct drm_file * file_priv)417 int drm_legacy_getctx(struct drm_device *dev, void *data,
418 		      struct drm_file *file_priv)
419 {
420 	struct drm_ctx *ctx = data;
421 
422 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
423 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
424 		return -EOPNOTSUPP;
425 
426 	/* This is 0, because we don't handle any context flags */
427 	ctx->flags = 0;
428 
429 	return 0;
430 }
431 
432 /*
433  * Switch context.
434  *
435  * \param inode device inode.
436  * \param file_priv DRM file private.
437  * \param cmd command.
438  * \param arg user argument pointing to a drm_ctx structure.
439  * \return zero on success or a negative number on failure.
440  *
441  * Calls context_switch().
442  */
drm_legacy_switchctx(struct drm_device * dev,void * data,struct drm_file * file_priv)443 int drm_legacy_switchctx(struct drm_device *dev, void *data,
444 			 struct drm_file *file_priv)
445 {
446 	struct drm_ctx *ctx = data;
447 
448 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
449 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
450 		return -EOPNOTSUPP;
451 
452 	DRM_DEBUG("%d\n", ctx->handle);
453 	return drm_context_switch(dev, dev->last_context, ctx->handle);
454 }
455 
456 /*
457  * New context.
458  *
459  * \param inode device inode.
460  * \param file_priv DRM file private.
461  * \param cmd command.
462  * \param arg user argument pointing to a drm_ctx structure.
463  * \return zero on success or a negative number on failure.
464  *
465  * Calls context_switch_complete().
466  */
drm_legacy_newctx(struct drm_device * dev,void * data,struct drm_file * file_priv)467 int drm_legacy_newctx(struct drm_device *dev, void *data,
468 		      struct drm_file *file_priv)
469 {
470 	struct drm_ctx *ctx = data;
471 
472 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
473 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
474 		return -EOPNOTSUPP;
475 
476 	DRM_DEBUG("%d\n", ctx->handle);
477 	drm_context_switch_complete(dev, file_priv, ctx->handle);
478 
479 	return 0;
480 }
481 
482 /*
483  * Remove context.
484  *
485  * \param inode device inode.
486  * \param file_priv DRM file private.
487  * \param cmd command.
488  * \param arg user argument pointing to a drm_ctx structure.
489  * \return zero on success or a negative number on failure.
490  *
491  * If not the special kernel context, calls ctxbitmap_free() to free the specified context.
492  */
drm_legacy_rmctx(struct drm_device * dev,void * data,struct drm_file * file_priv)493 int drm_legacy_rmctx(struct drm_device *dev, void *data,
494 		     struct drm_file *file_priv)
495 {
496 	struct drm_ctx *ctx = data;
497 
498 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
499 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
500 		return -EOPNOTSUPP;
501 
502 	DRM_DEBUG("%d\n", ctx->handle);
503 	if (ctx->handle != DRM_KERNEL_CONTEXT) {
504 		if (dev->driver->context_dtor)
505 			dev->driver->context_dtor(dev, ctx->handle);
506 		drm_legacy_ctxbitmap_free(dev, ctx->handle);
507 	}
508 
509 	mutex_lock(&dev->ctxlist_mutex);
510 	if (!list_empty(&dev->ctxlist)) {
511 		struct drm_ctx_list *pos, *n;
512 
513 		list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
514 			if (pos->handle == ctx->handle) {
515 				list_del(&pos->head);
516 				kfree(pos);
517 			}
518 		}
519 	}
520 	mutex_unlock(&dev->ctxlist_mutex);
521 
522 	return 0;
523 }
524 
525 /*@}*/
526