drivers/gpu/drm/drm_context.c

   1 /**
   2  * \file drm_context.c
   3  * IOCTLs for generic contexts
   4  *
   5  * \author Rickard E. (Rik) Faith <faith@valinux.com>
   6  * \author Gareth Hughes <gareth@valinux.com>
   7  */
   8
   9 /*
  10  * Created: Fri Nov 24 18:31:37 2000 by gareth@valinux.com
  11  *
  12  * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
  13  * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
  14  * All Rights Reserved.
  15  *
  16  * Permission is hereby granted, free of charge, to any person obtaining a
  17  * copy of this software and associated documentation files (the "Software"),
  18  * to deal in the Software without restriction, including without limitation
  19  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  20  * and/or sell copies of the Software, and to permit persons to whom the
  21  * Software is furnished to do so, subject to the following conditions:
  22  *
  23  * The above copyright notice and this permission notice (including the next
  24  * paragraph) shall be included in all copies or substantial portions of the
  25  * Software.
  26  *
  27  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  28  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  29  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  30  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  31  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  32  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  33  * OTHER DEALINGS IN THE SOFTWARE.
  34  */
  35
  36 /*
  37  * ChangeLog:
  38  *  2001-11-16  Torsten Duwe <duwe@caldera.de>
  39  *              added context constructor/destructor hooks,
  40  *              needed by SiS driver's memory management.
  41  */
  42
  43 #include <drm/drmP.h>
  44
  45 /**
  46  * Free a handle from the context bitmap.
  47  *
  48  * \param dev DRM device.
  49  * \param ctx_handle context handle.
  50  *
  51  * Clears the bit specified by \p ctx_handle in drm_device::ctx_bitmap and the entry
  52  * in drm_device::ctx_idr, while holding the drm_device::struct_mutex
  53  * lock.
  54  */
  55 static void drm_ctxbitmap_free(struct drm_device * dev, int ctx_handle)
  56 {
  57         if (drm_core_check_feature(dev, DRIVER_MODESET))
  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 /** \name Context bitmap support */
  67 /*@{*/
  68
  69 void drm_legacy_ctxbitmap_release(struct drm_device *dev,
  70                                   struct drm_file *file_priv)
  71 {
  72         if (drm_core_check_feature(dev, DRIVER_MODESET))
  73                 return;
  74
  75         mutex_lock(&dev->ctxlist_mutex);
  76         if (!list_empty(&dev->ctxlist)) {
  77                 struct drm_ctx_list *pos, *n;
  78
  79                 list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
  80                         if (pos->tag == file_priv &&
  81                             pos->handle != DRM_KERNEL_CONTEXT) {
  82                                 if (dev->driver->context_dtor)
  83                                         dev->driver->context_dtor(dev,
  84                                                                   pos->handle);
  85
  86                                 drm_ctxbitmap_free(dev, pos->handle);
  87
  88                                 list_del(&pos->head);
  89                                 kfree(pos);
  90                                 --dev->ctx_count;
  91                         }
  92                 }
  93         }
  94         mutex_unlock(&dev->ctxlist_mutex);
  95 }
  96
  97 /**
  98  * Context bitmap allocation.
  99  *
 100  * \param dev DRM device.
 101  * \return (non-negative) context handle on success or a negative number on failure.
 102  *
 103  * Allocate a new idr from drm_device::ctx_idr while holding the
 104  * drm_device::struct_mutex lock.
 105  */
 106 static int drm_ctxbitmap_next(struct drm_device * dev)
 107 {
 108         int ret;
 109
 110         mutex_lock(&dev->struct_mutex);
 111         ret = idr_alloc(&dev->ctx_idr, NULL, DRM_RESERVED_CONTEXTS, 0,
 112                         GFP_KERNEL);
 113         mutex_unlock(&dev->struct_mutex);
 114         return ret;
 115 }
 116
 117 /**
 118  * Context bitmap initialization.
 119  *
 120  * \param dev DRM device.
 121  *
 122  * Initialise the drm_device::ctx_idr
 123  */
 124 void drm_legacy_ctxbitmap_init(struct drm_device * dev)
 125 {
 126         if (drm_core_check_feature(dev, DRIVER_MODESET))
 127                 return;
 128
 129         idr_init(&dev->ctx_idr);
 130 }
 131
 132 /**
 133  * Context bitmap cleanup.
 134  *
 135  * \param dev DRM device.
 136  *
 137  * Free all idr members using drm_ctx_sarea_free helper function
 138  * while holding the drm_device::struct_mutex lock.
 139  */
 140 void drm_legacy_ctxbitmap_cleanup(struct drm_device * dev)
 141 {
 142         mutex_lock(&dev->struct_mutex);
 143         idr_destroy(&dev->ctx_idr);
 144         mutex_unlock(&dev->struct_mutex);
 145 }
 146
 147 /*@}*/
 148
 149 /******************************************************************/
 150 /** \name Per Context SAREA Support */
 151 /*@{*/
 152
 153 /**
 154  * Get per-context SAREA.
 155  *
 156  * \param inode device inode.
 157  * \param file_priv DRM file private.
 158  * \param cmd command.
 159  * \param arg user argument pointing to a drm_ctx_priv_map structure.
 160  * \return zero on success or a negative number on failure.
 161  *
 162  * Gets the map from drm_device::ctx_idr with the handle specified and
 163  * returns its handle.
 164  */
 165 int drm_getsareactx(struct drm_device *dev, void *data,
 166                     struct drm_file *file_priv)
 167 {
 168         struct drm_ctx_priv_map *request = data;
 169         struct drm_local_map *map;
 170         struct drm_map_list *_entry;
 171
 172         if (drm_core_check_feature(dev, DRIVER_MODESET))
 173                 return -EINVAL;
 174
 175         mutex_lock(&dev->struct_mutex);
 176
 177         map = idr_find(&dev->ctx_idr, request->ctx_id);
 178         if (!map) {
 179                 mutex_unlock(&dev->struct_mutex);
 180                 return -EINVAL;
 181         }
 182
 183         request->handle = NULL;
 184         list_for_each_entry(_entry, &dev->maplist, head) {
 185                 if (_entry->map == map) {
 186                         request->handle =
 187                             (void *)(unsigned long)_entry->user_token;
 188                         break;
 189                 }
 190         }
 191
 192         mutex_unlock(&dev->struct_mutex);
 193
 194         if (request->handle == NULL)
 195                 return -EINVAL;
 196
 197         return 0;
 198 }
 199
 200 /**
 201  * Set per-context SAREA.
 202  *
 203  * \param inode device inode.
 204  * \param file_priv DRM file private.
 205  * \param cmd command.
 206  * \param arg user argument pointing to a drm_ctx_priv_map structure.
 207  * \return zero on success or a negative number on failure.
 208  *
 209  * Searches the mapping specified in \p arg and update the entry in
 210  * drm_device::ctx_idr with it.
 211  */
 212 int drm_setsareactx(struct drm_device *dev, void *data,
 213                     struct drm_file *file_priv)
 214 {
 215         struct drm_ctx_priv_map *request = data;
 216         struct drm_local_map *map = NULL;
 217         struct drm_map_list *r_list = NULL;
 218
 219         if (drm_core_check_feature(dev, DRIVER_MODESET))
 220                 return -EINVAL;
 221
 222         mutex_lock(&dev->struct_mutex);
 223         list_for_each_entry(r_list, &dev->maplist, head) {
 224                 if (r_list->map
 225                     && r_list->user_token == (unsigned long) request->handle)
 226                         goto found;
 227         }
 228       bad:
 229         mutex_unlock(&dev->struct_mutex);
 230         return -EINVAL;
 231
 232       found:
 233         map = r_list->map;
 234         if (!map)
 235                 goto bad;
 236
 237         if (IS_ERR(idr_replace(&dev->ctx_idr, map, request->ctx_id)))
 238                 goto bad;
 239
 240         mutex_unlock(&dev->struct_mutex);
 241
 242         return 0;
 243 }
 244
 245 /*@}*/
 246
 247 /******************************************************************/
 248 /** \name The actual DRM context handling routines */
 249 /*@{*/
 250
 251 /**
 252  * Switch context.
 253  *
 254  * \param dev DRM device.
 255  * \param old old context handle.
 256  * \param new new context handle.
 257  * \return zero on success or a negative number on failure.
 258  *
 259  * Attempt to set drm_device::context_flag.
 260  */
 261 static int drm_context_switch(struct drm_device * dev, int old, int new)
 262 {
 263         if (test_and_set_bit(0, &dev->context_flag)) {
 264                 DRM_ERROR("Reentering -- FIXME\n");
 265                 return -EBUSY;
 266         }
 267
 268         DRM_DEBUG("Context switch from %d to %d\n", old, new);
 269
 270         if (new == dev->last_context) {
 271                 clear_bit(0, &dev->context_flag);
 272                 return 0;
 273         }
 274
 275         return 0;
 276 }
 277
 278 /**
 279  * Complete context switch.
 280  *
 281  * \param dev DRM device.
 282  * \param new new context handle.
 283  * \return zero on success or a negative number on failure.
 284  *
 285  * Updates drm_device::last_context and drm_device::last_switch. Verifies the
 286  * hardware lock is held, clears the drm_device::context_flag and wakes up
 287  * drm_device::context_wait.
 288  */
 289 static int drm_context_switch_complete(struct drm_device *dev,
 290                                        struct drm_file *file_priv, int new)
 291 {
 292         dev->last_context = new;        /* PRE/POST: This is the _only_ writer. */
 293
 294         if (!_DRM_LOCK_IS_HELD(file_priv->master->lock.hw_lock->lock)) {
 295                 DRM_ERROR("Lock isn't held after context switch\n");
 296         }
 297
 298         /* If a context switch is ever initiated
 299            when the kernel holds the lock, release
 300            that lock here. */
 301         clear_bit(0, &dev->context_flag);
 302
 303         return 0;
 304 }
 305
 306 /**
 307  * Reserve contexts.
 308  *
 309  * \param inode device inode.
 310  * \param file_priv DRM file private.
 311  * \param cmd command.
 312  * \param arg user argument pointing to a drm_ctx_res structure.
 313  * \return zero on success or a negative number on failure.
 314  */
 315 int drm_resctx(struct drm_device *dev, void *data,
 316                struct drm_file *file_priv)
 317 {
 318         struct drm_ctx_res *res = data;
 319         struct drm_ctx ctx;
 320         int i;
 321
 322         if (drm_core_check_feature(dev, DRIVER_MODESET))
 323                 return -EINVAL;
 324
 325         if (res->count >= DRM_RESERVED_CONTEXTS) {
 326                 memset(&ctx, 0, sizeof(ctx));
 327                 for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
 328                         ctx.handle = i;
 329                         if (copy_to_user(&res->contexts[i], &ctx, sizeof(ctx)))
 330                                 return -EFAULT;
 331                 }
 332         }
 333         res->count = DRM_RESERVED_CONTEXTS;
 334
 335         return 0;
 336 }
 337
 338 /**
 339  * Add context.
 340  *
 341  * \param inode device inode.
 342  * \param file_priv DRM file private.
 343  * \param cmd command.
 344  * \param arg user argument pointing to a drm_ctx structure.
 345  * \return zero on success or a negative number on failure.
 346  *
 347  * Get a new handle for the context and copy to userspace.
 348  */
 349 int drm_addctx(struct drm_device *dev, void *data,
 350                struct drm_file *file_priv)
 351 {
 352         struct drm_ctx_list *ctx_entry;
 353         struct drm_ctx *ctx = data;
 354
 355         if (drm_core_check_feature(dev, DRIVER_MODESET))
 356                 return -EINVAL;
 357
 358         ctx->handle = drm_ctxbitmap_next(dev);
 359         if (ctx->handle == DRM_KERNEL_CONTEXT) {
 360                 /* Skip kernel's context and get a new one. */
 361                 ctx->handle = drm_ctxbitmap_next(dev);
 362         }
 363         DRM_DEBUG("%d\n", ctx->handle);
 364         if (ctx->handle == -1) {
 365                 DRM_DEBUG("Not enough free contexts.\n");
 366                 /* Should this return -EBUSY instead? */
 367                 return -ENOMEM;
 368         }
 369
 370         ctx_entry = kmalloc(sizeof(*ctx_entry), GFP_KERNEL);
 371         if (!ctx_entry) {
 372                 DRM_DEBUG("out of memory\n");
 373                 return -ENOMEM;
 374         }
 375
 376         INIT_LIST_HEAD(&ctx_entry->head);
 377         ctx_entry->handle = ctx->handle;
 378         ctx_entry->tag = file_priv;
 379
 380         mutex_lock(&dev->ctxlist_mutex);
 381         list_add(&ctx_entry->head, &dev->ctxlist);
 382         ++dev->ctx_count;
 383         mutex_unlock(&dev->ctxlist_mutex);
 384
 385         return 0;
 386 }
 387
 388 /**
 389  * Get context.
 390  *
 391  * \param inode device inode.
 392  * \param file_priv DRM file private.
 393  * \param cmd command.
 394  * \param arg user argument pointing to a drm_ctx structure.
 395  * \return zero on success or a negative number on failure.
 396  */
 397 int drm_getctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
 398 {
 399         struct drm_ctx *ctx = data;
 400
 401         if (drm_core_check_feature(dev, DRIVER_MODESET))
 402                 return -EINVAL;
 403
 404         /* This is 0, because we don't handle any context flags */
 405         ctx->flags = 0;
 406
 407         return 0;
 408 }
 409
 410 /**
 411  * Switch context.
 412  *
 413  * \param inode device inode.
 414  * \param file_priv DRM file private.
 415  * \param cmd command.
 416  * \param arg user argument pointing to a drm_ctx structure.
 417  * \return zero on success or a negative number on failure.
 418  *
 419  * Calls context_switch().
 420  */
 421 int drm_switchctx(struct drm_device *dev, void *data,
 422                   struct drm_file *file_priv)
 423 {
 424         struct drm_ctx *ctx = data;
 425
 426         if (drm_core_check_feature(dev, DRIVER_MODESET))
 427                 return -EINVAL;
 428
 429         DRM_DEBUG("%d\n", ctx->handle);
 430         return drm_context_switch(dev, dev->last_context, ctx->handle);
 431 }
 432
 433 /**
 434  * New context.
 435  *
 436  * \param inode device inode.
 437  * \param file_priv DRM file private.
 438  * \param cmd command.
 439  * \param arg user argument pointing to a drm_ctx structure.
 440  * \return zero on success or a negative number on failure.
 441  *
 442  * Calls context_switch_complete().
 443  */
 444 int drm_newctx(struct drm_device *dev, void *data,
 445                struct drm_file *file_priv)
 446 {
 447         struct drm_ctx *ctx = data;
 448
 449         if (drm_core_check_feature(dev, DRIVER_MODESET))
 450                 return -EINVAL;
 451
 452         DRM_DEBUG("%d\n", ctx->handle);
 453         drm_context_switch_complete(dev, file_priv, ctx->handle);
 454
 455         return 0;
 456 }
 457
 458 /**
 459  * Remove context.
 460  *
 461  * \param inode device inode.
 462  * \param file_priv DRM file private.
 463  * \param cmd command.
 464  * \param arg user argument pointing to a drm_ctx structure.
 465  * \return zero on success or a negative number on failure.
 466  *
 467  * If not the special kernel context, calls ctxbitmap_free() to free the specified context.
 468  */
 469 int drm_rmctx(struct drm_device *dev, void *data,
 470               struct drm_file *file_priv)
 471 {
 472         struct drm_ctx *ctx = data;
 473
 474         if (drm_core_check_feature(dev, DRIVER_MODESET))
 475                 return -EINVAL;
 476
 477         DRM_DEBUG("%d\n", ctx->handle);
 478         if (ctx->handle != DRM_KERNEL_CONTEXT) {
 479                 if (dev->driver->context_dtor)
 480                         dev->driver->context_dtor(dev, ctx->handle);
 481                 drm_ctxbitmap_free(dev, ctx->handle);
 482         }
 483
 484         mutex_lock(&dev->ctxlist_mutex);
 485         if (!list_empty(&dev->ctxlist)) {
 486                 struct drm_ctx_list *pos, *n;
 487
 488                 list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
 489                         if (pos->handle == ctx->handle) {
 490                                 list_del(&pos->head);
 491                                 kfree(pos);
 492                                 --dev->ctx_count;
 493                         }
 494                 }
 495         }
 496         mutex_unlock(&dev->ctxlist_mutex);
 497
 498         return 0;
 499 }
 500
 501 /*@}*/