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_sem
  57  * lock.
  58  */
  59 void drm_ctxbitmap_free(drm_device_t * 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                 down(&dev->struct_sem);
  68                 clear_bit(ctx_handle, dev->ctx_bitmap);
  69                 dev->context_sareas[ctx_handle] = NULL;
  70                 up(&dev->struct_sem);
  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_sem lock.
  87  */
  88 static int drm_ctxbitmap_next(drm_device_t * dev)
  89 {
  90         int bit;
  91
  92         if (!dev->ctx_bitmap)
  93                 return -1;
  94
  95         down(&dev->struct_sem);
  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                                 drm_map_t **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                                         up(&dev->struct_sem);
 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                                         up(&dev->struct_sem);
 130                                         return -1;
 131                                 }
 132                                 dev->context_sareas[bit] = NULL;
 133                         }
 134                 }
 135                 up(&dev->struct_sem);
 136                 return bit;
 137         }
 138         up(&dev->struct_sem);
 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_sem lock.
 149  */
 150 int drm_ctxbitmap_init(drm_device_t * dev)
 151 {
 152         int i;
 153         int temp;
 154
 155         down(&dev->struct_sem);
 156         dev->ctx_bitmap = (unsigned long *)drm_alloc(PAGE_SIZE,
 157                                                      DRM_MEM_CTXBITMAP);
 158         if (dev->ctx_bitmap == NULL) {
 159                 up(&dev->struct_sem);
 160                 return -ENOMEM;
 161         }
 162         memset((void *)dev->ctx_bitmap, 0, PAGE_SIZE);
 163         dev->context_sareas = NULL;
 164         dev->max_context = -1;
 165         up(&dev->struct_sem);
 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_sem lock.
 182  */
 183 void drm_ctxbitmap_cleanup(drm_device_t * dev)
 184 {
 185         down(&dev->struct_sem);
 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         up(&dev->struct_sem);
 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         drm_file_t *priv = filp->private_data;
 216         drm_device_t *dev = priv->head->dev;
 217         drm_ctx_priv_map_t __user *argp = (void __user *)arg;
 218         drm_ctx_priv_map_t request;
 219         drm_map_t *map;
 220         drm_map_list_t *_entry;
 221
 222         if (copy_from_user(&request, argp, sizeof(request)))
 223                 return -EFAULT;
 224
 225         down(&dev->struct_sem);
 226         if (dev->max_context < 0
 227             || request.ctx_id >= (unsigned)dev->max_context) {
 228                 up(&dev->struct_sem);
 229                 return -EINVAL;
 230         }
 231
 232         map = dev->context_sareas[request.ctx_id];
 233         up(&dev->struct_sem);
 234
 235         request.handle = 0;
 236         list_for_each_entry(_entry, &dev->maplist->head, head) {
 237                 if (_entry->map == map) {
 238                         request.handle =
 239                             (void *)(unsigned long)_entry->user_token;
 240                         break;
 241                 }
 242         }
 243         if (request.handle == 0)
 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         drm_file_t *priv = filp->private_data;
 267         drm_device_t *dev = priv->head->dev;
 268         drm_ctx_priv_map_t request;
 269         drm_map_t *map = NULL;
 270         drm_map_list_t *r_list = NULL;
 271         struct list_head *list;
 272
 273         if (copy_from_user(&request,
 274                            (drm_ctx_priv_map_t __user *) arg, sizeof(request)))
 275                 return -EFAULT;
 276
 277         down(&dev->struct_sem);
 278         list_for_each(list, &dev->maplist->head) {
 279                 r_list = list_entry(list, drm_map_list_t, head);
 280                 if (r_list->map
 281                     && r_list->user_token == (unsigned long)request.handle)
 282                         goto found;
 283         }
 284       bad:
 285         up(&dev->struct_sem);
 286         return -EINVAL;
 287
 288       found:
 289         map = r_list->map;
 290         if (!map)
 291                 goto bad;
 292         if (dev->max_context < 0)
 293                 goto bad;
 294         if (request.ctx_id >= (unsigned)dev->max_context)
 295                 goto bad;
 296         dev->context_sareas[request.ctx_id] = map;
 297         up(&dev->struct_sem);
 298         return 0;
 299 }
 300
 301 /*@}*/
 302
 303 /******************************************************************/
 304 /** \name The actual DRM context handling routines */
 305 /*@{*/
 306
 307 /**
 308  * Switch context.
 309  *
 310  * \param dev DRM device.
 311  * \param old old context handle.
 312  * \param new new context handle.
 313  * \return zero on success or a negative number on failure.
 314  *
 315  * Attempt to set drm_device::context_flag.
 316  */
 317 static int drm_context_switch(drm_device_t * dev, int old, int new)
 318 {
 319         if (test_and_set_bit(0, &dev->context_flag)) {
 320                 DRM_ERROR("Reentering -- FIXME\n");
 321                 return -EBUSY;
 322         }
 323
 324         DRM_DEBUG("Context switch from %d to %d\n", old, new);
 325
 326         if (new == dev->last_context) {
 327                 clear_bit(0, &dev->context_flag);
 328                 return 0;
 329         }
 330
 331         return 0;
 332 }
 333
 334 /**
 335  * Complete context switch.
 336  *
 337  * \param dev DRM device.
 338  * \param new new context handle.
 339  * \return zero on success or a negative number on failure.
 340  *
 341  * Updates drm_device::last_context and drm_device::last_switch. Verifies the
 342  * hardware lock is held, clears the drm_device::context_flag and wakes up
 343  * drm_device::context_wait.
 344  */
 345 static int drm_context_switch_complete(drm_device_t * dev, int new)
 346 {
 347         dev->last_context = new;        /* PRE/POST: This is the _only_ writer. */
 348         dev->last_switch = jiffies;
 349
 350         if (!_DRM_LOCK_IS_HELD(dev->lock.hw_lock->lock)) {
 351                 DRM_ERROR("Lock isn't held after context switch\n");
 352         }
 353
 354         /* If a context switch is ever initiated
 355            when the kernel holds the lock, release
 356            that lock here. */
 357         clear_bit(0, &dev->context_flag);
 358         wake_up(&dev->context_wait);
 359
 360         return 0;
 361 }
 362
 363 /**
 364  * Reserve contexts.
 365  *
 366  * \param inode device inode.
 367  * \param filp file pointer.
 368  * \param cmd command.
 369  * \param arg user argument pointing to a drm_ctx_res structure.
 370  * \return zero on success or a negative number on failure.
 371  */
 372 int drm_resctx(struct inode *inode, struct file *filp,
 373                unsigned int cmd, unsigned long arg)
 374 {
 375         drm_ctx_res_t res;
 376         drm_ctx_t __user *argp = (void __user *)arg;
 377         drm_ctx_t ctx;
 378         int i;
 379
 380         if (copy_from_user(&res, argp, sizeof(res)))
 381                 return -EFAULT;
 382
 383         if (res.count >= DRM_RESERVED_CONTEXTS) {
 384                 memset(&ctx, 0, sizeof(ctx));
 385                 for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
 386                         ctx.handle = i;
 387                         if (copy_to_user(&res.contexts[i], &ctx, sizeof(ctx)))
 388                                 return -EFAULT;
 389                 }
 390         }
 391         res.count = DRM_RESERVED_CONTEXTS;
 392
 393         if (copy_to_user(argp, &res, sizeof(res)))
 394                 return -EFAULT;
 395         return 0;
 396 }
 397
 398 /**
 399  * Add context.
 400  *
 401  * \param inode device inode.
 402  * \param filp file pointer.
 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  * Get a new handle for the context and copy to userspace.
 408  */
 409 int drm_addctx(struct inode *inode, struct file *filp,
 410                unsigned int cmd, unsigned long arg)
 411 {
 412         drm_file_t *priv = filp->private_data;
 413         drm_device_t *dev = priv->head->dev;
 414         drm_ctx_list_t *ctx_entry;
 415         drm_ctx_t __user *argp = (void __user *)arg;
 416         drm_ctx_t ctx;
 417
 418         if (copy_from_user(&ctx, argp, sizeof(ctx)))
 419                 return -EFAULT;
 420
 421         ctx.handle = drm_ctxbitmap_next(dev);
 422         if (ctx.handle == DRM_KERNEL_CONTEXT) {
 423                 /* Skip kernel's context and get a new one. */
 424                 ctx.handle = drm_ctxbitmap_next(dev);
 425         }
 426         DRM_DEBUG("%d\n", ctx.handle);
 427         if (ctx.handle == -1) {
 428                 DRM_DEBUG("Not enough free contexts.\n");
 429                 /* Should this return -EBUSY instead? */
 430                 return -ENOMEM;
 431         }
 432
 433         if (ctx.handle != DRM_KERNEL_CONTEXT) {
 434                 if (dev->driver->context_ctor)
 435                         dev->driver->context_ctor(dev, ctx.handle);
 436         }
 437
 438         ctx_entry = drm_alloc(sizeof(*ctx_entry), DRM_MEM_CTXLIST);
 439         if (!ctx_entry) {
 440                 DRM_DEBUG("out of memory\n");
 441                 return -ENOMEM;
 442         }
 443
 444         INIT_LIST_HEAD(&ctx_entry->head);
 445         ctx_entry->handle = ctx.handle;
 446         ctx_entry->tag = priv;
 447
 448         down(&dev->ctxlist_sem);
 449         list_add(&ctx_entry->head, &dev->ctxlist->head);
 450         ++dev->ctx_count;
 451         up(&dev->ctxlist_sem);
 452
 453         if (copy_to_user(argp, &ctx, sizeof(ctx)))
 454                 return -EFAULT;
 455         return 0;
 456 }
 457
 458 int drm_modctx(struct inode *inode, struct file *filp,
 459                unsigned int cmd, unsigned long arg)
 460 {
 461         /* This does nothing */
 462         return 0;
 463 }
 464
 465 /**
 466  * Get context.
 467  *
 468  * \param inode device inode.
 469  * \param filp file pointer.
 470  * \param cmd command.
 471  * \param arg user argument pointing to a drm_ctx structure.
 472  * \return zero on success or a negative number on failure.
 473  */
 474 int drm_getctx(struct inode *inode, struct file *filp,
 475                unsigned int cmd, unsigned long arg)
 476 {
 477         drm_ctx_t __user *argp = (void __user *)arg;
 478         drm_ctx_t ctx;
 479
 480         if (copy_from_user(&ctx, argp, sizeof(ctx)))
 481                 return -EFAULT;
 482
 483         /* This is 0, because we don't handle any context flags */
 484         ctx.flags = 0;
 485
 486         if (copy_to_user(argp, &ctx, sizeof(ctx)))
 487                 return -EFAULT;
 488         return 0;
 489 }
 490
 491 /**
 492  * Switch context.
 493  *
 494  * \param inode device inode.
 495  * \param filp file pointer.
 496  * \param cmd command.
 497  * \param arg user argument pointing to a drm_ctx structure.
 498  * \return zero on success or a negative number on failure.
 499  *
 500  * Calls context_switch().
 501  */
 502 int drm_switchctx(struct inode *inode, struct file *filp,
 503                   unsigned int cmd, unsigned long arg)
 504 {
 505         drm_file_t *priv = filp->private_data;
 506         drm_device_t *dev = priv->head->dev;
 507         drm_ctx_t ctx;
 508
 509         if (copy_from_user(&ctx, (drm_ctx_t __user *) arg, sizeof(ctx)))
 510                 return -EFAULT;
 511
 512         DRM_DEBUG("%d\n", ctx.handle);
 513         return drm_context_switch(dev, dev->last_context, ctx.handle);
 514 }
 515
 516 /**
 517  * New context.
 518  *
 519  * \param inode device inode.
 520  * \param filp file pointer.
 521  * \param cmd command.
 522  * \param arg user argument pointing to a drm_ctx structure.
 523  * \return zero on success or a negative number on failure.
 524  *
 525  * Calls context_switch_complete().
 526  */
 527 int drm_newctx(struct inode *inode, struct file *filp,
 528                unsigned int cmd, unsigned long arg)
 529 {
 530         drm_file_t *priv = filp->private_data;
 531         drm_device_t *dev = priv->head->dev;
 532         drm_ctx_t ctx;
 533
 534         if (copy_from_user(&ctx, (drm_ctx_t __user *) arg, sizeof(ctx)))
 535                 return -EFAULT;
 536
 537         DRM_DEBUG("%d\n", ctx.handle);
 538         drm_context_switch_complete(dev, ctx.handle);
 539
 540         return 0;
 541 }
 542
 543 /**
 544  * Remove context.
 545  *
 546  * \param inode device inode.
 547  * \param filp file pointer.
 548  * \param cmd command.
 549  * \param arg user argument pointing to a drm_ctx structure.
 550  * \return zero on success or a negative number on failure.
 551  *
 552  * If not the special kernel context, calls ctxbitmap_free() to free the specified context.
 553  */
 554 int drm_rmctx(struct inode *inode, struct file *filp,
 555               unsigned int cmd, unsigned long arg)
 556 {
 557         drm_file_t *priv = filp->private_data;
 558         drm_device_t *dev = priv->head->dev;
 559         drm_ctx_t ctx;
 560
 561         if (copy_from_user(&ctx, (drm_ctx_t __user *) arg, sizeof(ctx)))
 562                 return -EFAULT;
 563
 564         DRM_DEBUG("%d\n", ctx.handle);
 565         if (ctx.handle == DRM_KERNEL_CONTEXT + 1) {
 566                 priv->remove_auth_on_close = 1;
 567         }
 568         if (ctx.handle != DRM_KERNEL_CONTEXT) {
 569                 if (dev->driver->context_dtor)
 570                         dev->driver->context_dtor(dev, ctx.handle);
 571                 drm_ctxbitmap_free(dev, ctx.handle);
 572         }
 573
 574         down(&dev->ctxlist_sem);
 575         if (!list_empty(&dev->ctxlist->head)) {
 576                 drm_ctx_list_t *pos, *n;
 577
 578                 list_for_each_entry_safe(pos, n, &dev->ctxlist->head, head) {
 579                         if (pos->handle == ctx.handle) {
 580                                 list_del(&pos->head);
 581                                 drm_free(pos, sizeof(*pos), DRM_MEM_CTXLIST);
 582                                 --dev->ctx_count;
 583                         }
 584                 }
 585         }
 586         up(&dev->ctxlist_sem);
 587
 588         return 0;
 589 }
 590
 591 /*@}*/