drivers/char/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 "drmP.h"
  44
  45 /******************************************************************/
  46 /** \name Context bitmap support */
  47 /*@{*/
  48
  49 /**
  50  * Free a handle from the context bitmap.
  51  *
  52  * \param dev DRM device.
  53  * \param ctx_handle context handle.
  54  *
  55  * Clears the bit specified by \p ctx_handle in drm_device::ctx_bitmap and the entry
  56  * in drm_device::context_sareas, while holding the drm_device::struct_mutex
  57  * lock.
  58  */
  59 void drm_ctxbitmap_free(struct drm_device * dev, int ctx_handle)
  60 {
  61         if (ctx_handle < 0)
  62                 goto failed;
  63         if (!dev->ctx_bitmap)
  64                 goto failed;
  65
  66         if (ctx_handle < DRM_MAX_CTXBITMAP) {
  67                 mutex_lock(&dev->struct_mutex);
  68                 clear_bit(ctx_handle, dev->ctx_bitmap);
  69                 dev->context_sareas[ctx_handle] = NULL;
  70                 mutex_unlock(&dev->struct_mutex);
  71                 return;
  72         }
  73       failed:
  74         DRM_ERROR("Attempt to free invalid context handle: %d\n", ctx_handle);
  75         return;
  76 }
  77
  78 /**
  79  * Context bitmap allocation.
  80  *
  81  * \param dev DRM device.
  82  * \return (non-negative) context handle on success or a negative number on failure.
  83  *
  84  * Find the first zero bit in drm_device::ctx_bitmap and (re)allocates
  85  * drm_device::context_sareas to accommodate the new entry while holding the
  86  * drm_device::struct_mutex lock.
  87  */
  88 static int drm_ctxbitmap_next(struct drm_device * dev)
  89 {
  90         int bit;
  91
  92         if (!dev->ctx_bitmap)
  93                 return -1;
  94
  95         mutex_lock(&dev->struct_mutex);
  96         bit = find_first_zero_bit(dev->ctx_bitmap, DRM_MAX_CTXBITMAP);
  97         if (bit < DRM_MAX_CTXBITMAP) {
  98                 set_bit(bit, dev->ctx_bitmap);
  99                 DRM_DEBUG("drm_ctxbitmap_next bit : %d\n", bit);
 100                 if ((bit + 1) > dev->max_context) {
 101                         dev->max_context = (bit + 1);
 102                         if (dev->context_sareas) {
 103                                 struct drm_map **ctx_sareas;
 104
 105                                 ctx_sareas = drm_realloc(dev->context_sareas,
 106                                                          (dev->max_context -
 107                                                           1) *
 108                                                          sizeof(*dev->
 109                                                                 context_sareas),
 110                                                          dev->max_context *
 111                                                          sizeof(*dev->
 112                                                                 context_sareas),
 113                                                          DRM_MEM_MAPS);
 114                                 if (!ctx_sareas) {
 115                                         clear_bit(bit, dev->ctx_bitmap);
 116                                         mutex_unlock(&dev->struct_mutex);
 117                                         return -1;
 118                                 }
 119                                 dev->context_sareas = ctx_sareas;
 120                                 dev->context_sareas[bit] = NULL;
 121                         } else {
 122                                 /* max_context == 1 at this point */
 123                                 dev->context_sareas =
 124                                     drm_alloc(dev->max_context *
 125                                               sizeof(*dev->context_sareas),
 126                                               DRM_MEM_MAPS);
 127                                 if (!dev->context_sareas) {
 128                                         clear_bit(bit, dev->ctx_bitmap);
 129                                         mutex_unlock(&dev->struct_mutex);
 130                                         return -1;
 131                                 }
 132                                 dev->context_sareas[bit] = NULL;
 133                         }
 134                 }
 135                 mutex_unlock(&dev->struct_mutex);
 136                 return bit;
 137         }
 138         mutex_unlock(&dev->struct_mutex);
 139         return -1;
 140 }
 141
 142 /**
 143  * Context bitmap initialization.
 144  *
 145  * \param dev DRM device.
 146  *
 147  * Allocates and initialize drm_device::ctx_bitmap and drm_device::context_sareas, while holding
 148  * the drm_device::struct_mutex lock.
 149  */
 150 int drm_ctxbitmap_init(struct drm_device * dev)
 151 {
 152         int i;
 153         int temp;
 154
 155         mutex_lock(&dev->struct_mutex);
 156         dev->ctx_bitmap = (unsigned long *)drm_alloc(PAGE_SIZE,
 157                                                      DRM_MEM_CTXBITMAP);
 158         if (dev->ctx_bitmap == NULL) {
 159                 mutex_unlock(&dev->struct_mutex);
 160                 return -ENOMEM;
 161         }
 162         memset((void *)dev->ctx_bitmap, 0, PAGE_SIZE);
 163         dev->context_sareas = NULL;
 164         dev->max_context = -1;
 165         mutex_unlock(&dev->struct_mutex);
 166
 167         for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
 168                 temp = drm_ctxbitmap_next(dev);
 169                 DRM_DEBUG("drm_ctxbitmap_init : %d\n", temp);
 170         }
 171
 172         return 0;
 173 }
 174
 175 /**
 176  * Context bitmap cleanup.
 177  *
 178  * \param dev DRM device.
 179  *
 180  * Frees drm_device::ctx_bitmap and drm_device::context_sareas, while holding
 181  * the drm_device::struct_mutex lock.
 182  */
 183 void drm_ctxbitmap_cleanup(struct drm_device * dev)
 184 {
 185         mutex_lock(&dev->struct_mutex);
 186         if (dev->context_sareas)
 187                 drm_free(dev->context_sareas,
 188                          sizeof(*dev->context_sareas) *
 189                          dev->max_context, DRM_MEM_MAPS);
 190         drm_free((void *)dev->ctx_bitmap, PAGE_SIZE, DRM_MEM_CTXBITMAP);
 191         mutex_unlock(&dev->struct_mutex);
 192 }
 193
 194 /*@}*/
 195
 196 /******************************************************************/
 197 /** \name Per Context SAREA Support */
 198 /*@{*/
 199
 200 /**
 201  * Get per-context SAREA.
 202  *
 203  * \param inode device inode.
 204  * \param filp file pointer.
 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  * Gets the map from drm_device::context_sareas with the handle specified and
 210  * returns its handle.
 211  */
 212 int drm_getsareactx(struct inode *inode, struct file *filp,
 213                     unsigned int cmd, unsigned long arg)
 214 {
 215         struct drm_file *priv = filp->private_data;
 216         struct drm_device *dev = priv->head->dev;
 217         struct drm_ctx_priv_map __user *argp = (void __user *)arg;
 218         struct drm_ctx_priv_map request;
 219         struct drm_map *map;
 220         drm_map_list_t *_entry;
 221
 222         if (copy_from_user(&request, argp, sizeof(request)))
 223                 return -EFAULT;
 224
 225         mutex_lock(&dev->struct_mutex);
 226         if (dev->max_context < 0
 227             || request.ctx_id >= (unsigned)dev->max_context) {
 228                 mutex_unlock(&dev->struct_mutex);
 229                 return -EINVAL;
 230         }
 231
 232         map = dev->context_sareas[request.ctx_id];
 233         mutex_unlock(&dev->struct_mutex);
 234
 235         request.handle = NULL;
 236         list_for_each_entry(_entry, &dev->maplist, head) {
 237                 if (_entry->map == map) {
 238                         request.handle =
 239                             (void *)(unsigned long)_entry->user_token;
 240                         break;
 241                 }
 242         }
 243         if (request.handle == NULL)
 244                 return -EINVAL;
 245
 246         if (copy_to_user(argp, &request, sizeof(request)))
 247                 return -EFAULT;
 248         return 0;
 249 }
 250
 251 /**
 252  * Set per-context SAREA.
 253  *
 254  * \param inode device inode.
 255  * \param filp file pointer.
 256  * \param cmd command.
 257  * \param arg user argument pointing to a drm_ctx_priv_map structure.
 258  * \return zero on success or a negative number on failure.
 259  *
 260  * Searches the mapping specified in \p arg and update the entry in
 261  * drm_device::context_sareas with it.
 262  */
 263 int drm_setsareactx(struct inode *inode, struct file *filp,
 264                     unsigned int cmd, unsigned long arg)
 265 {
 266         struct drm_file *priv = filp->private_data;
 267         struct drm_device *dev = priv->head->dev;
 268         struct drm_ctx_priv_map request;
 269         struct drm_map *map = NULL;
 270         drm_map_list_t *r_list = NULL;
 271
 272         if (copy_from_user(&request,
 273                            (struct drm_ctx_priv_map __user *) arg,
 274                            sizeof(request)))
 275                 return -EFAULT;
 276
 277         mutex_lock(&dev->struct_mutex);
 278         list_for_each_entry(r_list, &dev->maplist, head) {
 279                 if (r_list->map
 280                     && r_list->user_token == (unsigned long)request.handle)
 281                         goto found;
 282         }
 283       bad:
 284         mutex_unlock(&dev->struct_mutex);
 285         return -EINVAL;
 286
 287       found:
 288         map = r_list->map;
 289         if (!map)
 290                 goto bad;
 291         if (dev->max_context < 0)
 292                 goto bad;
 293         if (request.ctx_id >= (unsigned)dev->max_context)
 294                 goto bad;
 295         dev->context_sareas[request.ctx_id] = map;
 296         mutex_unlock(&dev->struct_mutex);
 297         return 0;
 298 }
 299
 300 /*@}*/
 301
 302 /******************************************************************/
 303 /** \name The actual DRM context handling routines */
 304 /*@{*/
 305
 306 /**
 307  * Switch context.
 308  *
 309  * \param dev DRM device.
 310  * \param old old context handle.
 311  * \param new new context handle.
 312  * \return zero on success or a negative number on failure.
 313  *
 314  * Attempt to set drm_device::context_flag.
 315  */
 316 static int drm_context_switch(struct drm_device * dev, int old, int new)
 317 {
 318         if (test_and_set_bit(0, &dev->context_flag)) {
 319                 DRM_ERROR("Reentering -- FIXME\n");
 320                 return -EBUSY;
 321         }
 322
 323         DRM_DEBUG("Context switch from %d to %d\n", old, new);
 324
 325         if (new == dev->last_context) {
 326                 clear_bit(0, &dev->context_flag);
 327                 return 0;
 328         }
 329
 330         return 0;
 331 }
 332
 333 /**
 334  * Complete context switch.
 335  *
 336  * \param dev DRM device.
 337  * \param new new context handle.
 338  * \return zero on success or a negative number on failure.
 339  *
 340  * Updates drm_device::last_context and drm_device::last_switch. Verifies the
 341  * hardware lock is held, clears the drm_device::context_flag and wakes up
 342  * drm_device::context_wait.
 343  */
 344 static int drm_context_switch_complete(struct drm_device * dev, int new)
 345 {
 346         dev->last_context = new;        /* PRE/POST: This is the _only_ writer. */
 347         dev->last_switch = jiffies;
 348
 349         if (!_DRM_LOCK_IS_HELD(dev->lock.hw_lock->lock)) {
 350                 DRM_ERROR("Lock isn't held after context switch\n");
 351         }
 352
 353         /* If a context switch is ever initiated
 354            when the kernel holds the lock, release
 355            that lock here. */
 356         clear_bit(0, &dev->context_flag);
 357         wake_up(&dev->context_wait);
 358
 359         return 0;
 360 }
 361
 362 /**
 363  * Reserve contexts.
 364  *
 365  * \param inode device inode.
 366  * \param filp file pointer.
 367  * \param cmd command.
 368  * \param arg user argument pointing to a drm_ctx_res structure.
 369  * \return zero on success or a negative number on failure.
 370  */
 371 int drm_resctx(struct inode *inode, struct file *filp,
 372                unsigned int cmd, unsigned long arg)
 373 {
 374         struct drm_ctx_res res;
 375         struct drm_ctx_res __user *argp = (void __user *)arg;
 376         struct drm_ctx ctx;
 377         int i;
 378
 379         if (copy_from_user(&res, argp, sizeof(res)))
 380                 return -EFAULT;
 381
 382         if (res.count >= DRM_RESERVED_CONTEXTS) {
 383                 memset(&ctx, 0, sizeof(ctx));
 384                 for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
 385                         ctx.handle = i;
 386                         if (copy_to_user(&res.contexts[i], &ctx, sizeof(ctx)))
 387                                 return -EFAULT;
 388                 }
 389         }
 390         res.count = DRM_RESERVED_CONTEXTS;
 391
 392         if (copy_to_user(argp, &res, sizeof(res)))
 393                 return -EFAULT;
 394         return 0;
 395 }
 396
 397 /**
 398  * Add context.
 399  *
 400  * \param inode device inode.
 401  * \param filp file pointer.
 402  * \param cmd command.
 403  * \param arg user argument pointing to a drm_ctx structure.
 404  * \return zero on success or a negative number on failure.
 405  *
 406  * Get a new handle for the context and copy to userspace.
 407  */
 408 int drm_addctx(struct inode *inode, struct file *filp,
 409                unsigned int cmd, unsigned long arg)
 410 {
 411         struct drm_file *priv = filp->private_data;
 412         struct drm_device *dev = priv->head->dev;
 413         drm_ctx_list_t *ctx_entry;
 414         struct drm_ctx __user *argp = (void __user *)arg;
 415         struct drm_ctx ctx;
 416
 417         if (copy_from_user(&ctx, argp, sizeof(ctx)))
 418                 return -EFAULT;
 419
 420         ctx.handle = drm_ctxbitmap_next(dev);
 421         if (ctx.handle == DRM_KERNEL_CONTEXT) {
 422                 /* Skip kernel's context and get a new one. */
 423                 ctx.handle = drm_ctxbitmap_next(dev);
 424         }
 425         DRM_DEBUG("%d\n", ctx.handle);
 426         if (ctx.handle == -1) {
 427                 DRM_DEBUG("Not enough free contexts.\n");
 428                 /* Should this return -EBUSY instead? */
 429                 return -ENOMEM;
 430         }
 431
 432         if (ctx.handle != DRM_KERNEL_CONTEXT) {
 433                 if (dev->driver->context_ctor)
 434                         if (!dev->driver->context_ctor(dev, ctx.handle)) {
 435                                 DRM_DEBUG("Running out of ctxs or memory.\n");
 436                                 return -ENOMEM;
 437                         }
 438         }
 439
 440         ctx_entry = drm_alloc(sizeof(*ctx_entry), DRM_MEM_CTXLIST);
 441         if (!ctx_entry) {
 442                 DRM_DEBUG("out of memory\n");
 443                 return -ENOMEM;
 444         }
 445
 446         INIT_LIST_HEAD(&ctx_entry->head);
 447         ctx_entry->handle = ctx.handle;
 448         ctx_entry->tag = priv;
 449
 450         mutex_lock(&dev->ctxlist_mutex);
 451         list_add(&ctx_entry->head, &dev->ctxlist);
 452         ++dev->ctx_count;
 453         mutex_unlock(&dev->ctxlist_mutex);
 454
 455         if (copy_to_user(argp, &ctx, sizeof(ctx)))
 456                 return -EFAULT;
 457         return 0;
 458 }
 459
 460 int drm_modctx(struct inode *inode, struct file *filp,
 461                unsigned int cmd, unsigned long arg)
 462 {
 463         /* This does nothing */
 464         return 0;
 465 }
 466
 467 /**
 468  * Get context.
 469  *
 470  * \param inode device inode.
 471  * \param filp file pointer.
 472  * \param cmd command.
 473  * \param arg user argument pointing to a drm_ctx structure.
 474  * \return zero on success or a negative number on failure.
 475  */
 476 int drm_getctx(struct inode *inode, struct file *filp,
 477                unsigned int cmd, unsigned long arg)
 478 {
 479         struct drm_ctx __user *argp = (void __user *)arg;
 480         struct drm_ctx ctx;
 481
 482         if (copy_from_user(&ctx, argp, sizeof(ctx)))
 483                 return -EFAULT;
 484
 485         /* This is 0, because we don't handle any context flags */
 486         ctx.flags = 0;
 487
 488         if (copy_to_user(argp, &ctx, sizeof(ctx)))
 489                 return -EFAULT;
 490         return 0;
 491 }
 492
 493 /**
 494  * Switch context.
 495  *
 496  * \param inode device inode.
 497  * \param filp file pointer.
 498  * \param cmd command.
 499  * \param arg user argument pointing to a drm_ctx structure.
 500  * \return zero on success or a negative number on failure.
 501  *
 502  * Calls context_switch().
 503  */
 504 int drm_switchctx(struct inode *inode, struct file *filp,
 505                   unsigned int cmd, unsigned long arg)
 506 {
 507         struct drm_file *priv = filp->private_data;
 508         struct drm_device *dev = priv->head->dev;
 509         struct drm_ctx ctx;
 510
 511         if (copy_from_user(&ctx, (struct drm_ctx __user *) arg, sizeof(ctx)))
 512                 return -EFAULT;
 513
 514         DRM_DEBUG("%d\n", ctx.handle);
 515         return drm_context_switch(dev, dev->last_context, ctx.handle);
 516 }
 517
 518 /**
 519  * New context.
 520  *
 521  * \param inode device inode.
 522  * \param filp file pointer.
 523  * \param cmd command.
 524  * \param arg user argument pointing to a drm_ctx structure.
 525  * \return zero on success or a negative number on failure.
 526  *
 527  * Calls context_switch_complete().
 528  */
 529 int drm_newctx(struct inode *inode, struct file *filp,
 530                unsigned int cmd, unsigned long arg)
 531 {
 532         struct drm_file *priv = filp->private_data;
 533         struct drm_device *dev = priv->head->dev;
 534         struct drm_ctx ctx;
 535
 536         if (copy_from_user(&ctx, (struct drm_ctx __user *) arg, sizeof(ctx)))
 537                 return -EFAULT;
 538
 539         DRM_DEBUG("%d\n", ctx.handle);
 540         drm_context_switch_complete(dev, ctx.handle);
 541
 542         return 0;
 543 }
 544
 545 /**
 546  * Remove context.
 547  *
 548  * \param inode device inode.
 549  * \param filp file pointer.
 550  * \param cmd command.
 551  * \param arg user argument pointing to a drm_ctx structure.
 552  * \return zero on success or a negative number on failure.
 553  *
 554  * If not the special kernel context, calls ctxbitmap_free() to free the specified context.
 555  */
 556 int drm_rmctx(struct inode *inode, struct file *filp,
 557               unsigned int cmd, unsigned long arg)
 558 {
 559         struct drm_file *priv = filp->private_data;
 560         struct drm_device *dev = priv->head->dev;
 561         struct drm_ctx ctx;
 562
 563         if (copy_from_user(&ctx, (struct drm_ctx __user *) arg, sizeof(ctx)))
 564                 return -EFAULT;
 565
 566         DRM_DEBUG("%d\n", ctx.handle);
 567         if (ctx.handle == DRM_KERNEL_CONTEXT + 1) {
 568                 priv->remove_auth_on_close = 1;
 569         }
 570         if (ctx.handle != DRM_KERNEL_CONTEXT) {
 571                 if (dev->driver->context_dtor)
 572                         dev->driver->context_dtor(dev, ctx.handle);
 573                 drm_ctxbitmap_free(dev, ctx.handle);
 574         }
 575
 576         mutex_lock(&dev->ctxlist_mutex);
 577         if (!list_empty(&dev->ctxlist)) {
 578                 drm_ctx_list_t *pos, *n;
 579
 580                 list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
 581                         if (pos->handle == ctx.handle) {
 582                                 list_del(&pos->head);
 583                                 drm_free(pos, sizeof(*pos), DRM_MEM_CTXLIST);
 584                                 --dev->ctx_count;
 585                         }
 586                 }
 587         }
 588         mutex_unlock(&dev->ctxlist_mutex);
 589
 590         return 0;
 591 }
 592
 593 /*@}*/