xref: /openbmc/linux/drivers/gpu/drm/drm_context.c (revision 82e6fdd6)
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 <drm/drmP.h>
32 #include "drm_legacy.h"
33 
34 struct drm_ctx_list {
35 	struct list_head head;
36 	drm_context_t handle;
37 	struct drm_file *tag;
38 };
39 
40 /******************************************************************/
41 /** \name Context bitmap support */
42 /*@{*/
43 
44 /**
45  * Free a handle from the context bitmap.
46  *
47  * \param dev DRM device.
48  * \param ctx_handle context handle.
49  *
50  * Clears the bit specified by \p ctx_handle in drm_device::ctx_bitmap and the entry
51  * in drm_device::ctx_idr, while holding the drm_device::struct_mutex
52  * lock.
53  */
54 void drm_legacy_ctxbitmap_free(struct drm_device * dev, int ctx_handle)
55 {
56 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
57 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
58 		return;
59 
60 	mutex_lock(&dev->struct_mutex);
61 	idr_remove(&dev->ctx_idr, ctx_handle);
62 	mutex_unlock(&dev->struct_mutex);
63 }
64 
65 /**
66  * Context bitmap allocation.
67  *
68  * \param dev DRM device.
69  * \return (non-negative) context handle on success or a negative number on failure.
70  *
71  * Allocate a new idr from drm_device::ctx_idr while holding the
72  * drm_device::struct_mutex lock.
73  */
74 static int drm_legacy_ctxbitmap_next(struct drm_device * dev)
75 {
76 	int ret;
77 
78 	mutex_lock(&dev->struct_mutex);
79 	ret = idr_alloc(&dev->ctx_idr, NULL, DRM_RESERVED_CONTEXTS, 0,
80 			GFP_KERNEL);
81 	mutex_unlock(&dev->struct_mutex);
82 	return ret;
83 }
84 
85 /**
86  * Context bitmap initialization.
87  *
88  * \param dev DRM device.
89  *
90  * Initialise the drm_device::ctx_idr
91  */
92 void drm_legacy_ctxbitmap_init(struct drm_device * dev)
93 {
94 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
95 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
96 		return;
97 
98 	idr_init(&dev->ctx_idr);
99 }
100 
101 /**
102  * Context bitmap cleanup.
103  *
104  * \param dev DRM device.
105  *
106  * Free all idr members using drm_ctx_sarea_free helper function
107  * while holding the drm_device::struct_mutex lock.
108  */
109 void drm_legacy_ctxbitmap_cleanup(struct drm_device * dev)
110 {
111 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
112 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
113 		return;
114 
115 	mutex_lock(&dev->struct_mutex);
116 	idr_destroy(&dev->ctx_idr);
117 	mutex_unlock(&dev->struct_mutex);
118 }
119 
120 /**
121  * drm_ctxbitmap_flush() - Flush all contexts owned by a file
122  * @dev: DRM device to operate on
123  * @file: Open file to flush contexts for
124  *
125  * This iterates over all contexts on @dev and drops them if they're owned by
126  * @file. Note that after this call returns, new contexts might be added if
127  * the file is still alive.
128  */
129 void drm_legacy_ctxbitmap_flush(struct drm_device *dev, struct drm_file *file)
130 {
131 	struct drm_ctx_list *pos, *tmp;
132 
133 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
134 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
135 		return;
136 
137 	mutex_lock(&dev->ctxlist_mutex);
138 
139 	list_for_each_entry_safe(pos, tmp, &dev->ctxlist, head) {
140 		if (pos->tag == file &&
141 		    pos->handle != DRM_KERNEL_CONTEXT) {
142 			if (dev->driver->context_dtor)
143 				dev->driver->context_dtor(dev, pos->handle);
144 
145 			drm_legacy_ctxbitmap_free(dev, pos->handle);
146 			list_del(&pos->head);
147 			kfree(pos);
148 		}
149 	}
150 
151 	mutex_unlock(&dev->ctxlist_mutex);
152 }
153 
154 /*@}*/
155 
156 /******************************************************************/
157 /** \name Per Context SAREA Support */
158 /*@{*/
159 
160 /**
161  * Get per-context SAREA.
162  *
163  * \param inode device inode.
164  * \param file_priv DRM file private.
165  * \param cmd command.
166  * \param arg user argument pointing to a drm_ctx_priv_map structure.
167  * \return zero on success or a negative number on failure.
168  *
169  * Gets the map from drm_device::ctx_idr with the handle specified and
170  * returns its handle.
171  */
172 int drm_legacy_getsareactx(struct drm_device *dev, void *data,
173 			   struct drm_file *file_priv)
174 {
175 	struct drm_ctx_priv_map *request = data;
176 	struct drm_local_map *map;
177 	struct drm_map_list *_entry;
178 
179 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
180 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
181 		return -EINVAL;
182 
183 	mutex_lock(&dev->struct_mutex);
184 
185 	map = idr_find(&dev->ctx_idr, request->ctx_id);
186 	if (!map) {
187 		mutex_unlock(&dev->struct_mutex);
188 		return -EINVAL;
189 	}
190 
191 	request->handle = NULL;
192 	list_for_each_entry(_entry, &dev->maplist, head) {
193 		if (_entry->map == map) {
194 			request->handle =
195 			    (void *)(unsigned long)_entry->user_token;
196 			break;
197 		}
198 	}
199 
200 	mutex_unlock(&dev->struct_mutex);
201 
202 	if (request->handle == NULL)
203 		return -EINVAL;
204 
205 	return 0;
206 }
207 
208 /**
209  * Set per-context SAREA.
210  *
211  * \param inode device inode.
212  * \param file_priv DRM file private.
213  * \param cmd command.
214  * \param arg user argument pointing to a drm_ctx_priv_map structure.
215  * \return zero on success or a negative number on failure.
216  *
217  * Searches the mapping specified in \p arg and update the entry in
218  * drm_device::ctx_idr with it.
219  */
220 int drm_legacy_setsareactx(struct drm_device *dev, void *data,
221 			   struct drm_file *file_priv)
222 {
223 	struct drm_ctx_priv_map *request = data;
224 	struct drm_local_map *map = NULL;
225 	struct drm_map_list *r_list = NULL;
226 
227 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
228 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
229 		return -EINVAL;
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  */
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  */
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 	clear_bit(0, &dev->context_flag);
311 
312 	return 0;
313 }
314 
315 /**
316  * Reserve contexts.
317  *
318  * \param inode device inode.
319  * \param file_priv DRM file private.
320  * \param cmd command.
321  * \param arg user argument pointing to a drm_ctx_res structure.
322  * \return zero on success or a negative number on failure.
323  */
324 int drm_legacy_resctx(struct drm_device *dev, void *data,
325 		      struct drm_file *file_priv)
326 {
327 	struct drm_ctx_res *res = data;
328 	struct drm_ctx ctx;
329 	int i;
330 
331 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
332 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
333 		return -EINVAL;
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  */
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 
365 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
366 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
367 		return -EINVAL;
368 
369 	ctx->handle = drm_legacy_ctxbitmap_next(dev);
370 	if (ctx->handle == DRM_KERNEL_CONTEXT) {
371 		/* Skip kernel's context and get a new one. */
372 		ctx->handle = drm_legacy_ctxbitmap_next(dev);
373 	}
374 	DRM_DEBUG("%d\n", ctx->handle);
375 	if (ctx->handle == -1) {
376 		DRM_DEBUG("Not enough free contexts.\n");
377 		/* Should this return -EBUSY instead? */
378 		return -ENOMEM;
379 	}
380 
381 	ctx_entry = kmalloc(sizeof(*ctx_entry), GFP_KERNEL);
382 	if (!ctx_entry) {
383 		DRM_DEBUG("out of memory\n");
384 		return -ENOMEM;
385 	}
386 
387 	INIT_LIST_HEAD(&ctx_entry->head);
388 	ctx_entry->handle = ctx->handle;
389 	ctx_entry->tag = file_priv;
390 
391 	mutex_lock(&dev->ctxlist_mutex);
392 	list_add(&ctx_entry->head, &dev->ctxlist);
393 	mutex_unlock(&dev->ctxlist_mutex);
394 
395 	return 0;
396 }
397 
398 /**
399  * Get context.
400  *
401  * \param inode device inode.
402  * \param file_priv DRM file private.
403  * \param cmd command.
404  * \param arg user argument pointing to a drm_ctx structure.
405  * \return zero on success or a negative number on failure.
406  */
407 int drm_legacy_getctx(struct drm_device *dev, void *data,
408 		      struct drm_file *file_priv)
409 {
410 	struct drm_ctx *ctx = data;
411 
412 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
413 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
414 		return -EINVAL;
415 
416 	/* This is 0, because we don't handle any context flags */
417 	ctx->flags = 0;
418 
419 	return 0;
420 }
421 
422 /**
423  * Switch context.
424  *
425  * \param inode device inode.
426  * \param file_priv DRM file private.
427  * \param cmd command.
428  * \param arg user argument pointing to a drm_ctx structure.
429  * \return zero on success or a negative number on failure.
430  *
431  * Calls context_switch().
432  */
433 int drm_legacy_switchctx(struct drm_device *dev, void *data,
434 			 struct drm_file *file_priv)
435 {
436 	struct drm_ctx *ctx = data;
437 
438 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
439 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
440 		return -EINVAL;
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  */
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_KMS_LEGACY_CONTEXT) &&
463 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
464 		return -EINVAL;
465 
466 	DRM_DEBUG("%d\n", ctx->handle);
467 	drm_context_switch_complete(dev, file_priv, ctx->handle);
468 
469 	return 0;
470 }
471 
472 /**
473  * Remove context.
474  *
475  * \param inode device inode.
476  * \param file_priv DRM file private.
477  * \param cmd command.
478  * \param arg user argument pointing to a drm_ctx structure.
479  * \return zero on success or a negative number on failure.
480  *
481  * If not the special kernel context, calls ctxbitmap_free() to free the specified context.
482  */
483 int drm_legacy_rmctx(struct drm_device *dev, void *data,
484 		     struct drm_file *file_priv)
485 {
486 	struct drm_ctx *ctx = data;
487 
488 	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
489 	    !drm_core_check_feature(dev, DRIVER_LEGACY))
490 		return -EINVAL;
491 
492 	DRM_DEBUG("%d\n", ctx->handle);
493 	if (ctx->handle != DRM_KERNEL_CONTEXT) {
494 		if (dev->driver->context_dtor)
495 			dev->driver->context_dtor(dev, ctx->handle);
496 		drm_legacy_ctxbitmap_free(dev, ctx->handle);
497 	}
498 
499 	mutex_lock(&dev->ctxlist_mutex);
500 	if (!list_empty(&dev->ctxlist)) {
501 		struct drm_ctx_list *pos, *n;
502 
503 		list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
504 			if (pos->handle == ctx->handle) {
505 				list_del(&pos->head);
506 				kfree(pos);
507 			}
508 		}
509 	}
510 	mutex_unlock(&dev->ctxlist_mutex);
511 
512 	return 0;
513 }
514 
515 /*@}*/
516