drivers/gpu/drm/drm_context.c

   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         mutex_lock(&dev->struct_mutex);
  57         idr_remove(&dev->ctx_idr, ctx_handle);
  58         mutex_unlock(&dev->struct_mutex);
  59 }
  60
  61 /**
  62  * Context bitmap allocation.
  63  *
  64  * \param dev DRM device.
  65  * \return (non-negative) context handle on success or a negative number on failure.
  66  *
  67  * Allocate a new idr from drm_device::ctx_idr while holding the
  68  * drm_device::struct_mutex lock.
  69  */
  70 static int drm_legacy_ctxbitmap_next(struct drm_device * dev)
  71 {
  72         int ret;
  73
  74         mutex_lock(&dev->struct_mutex);
  75         ret = idr_alloc(&dev->ctx_idr, NULL, DRM_RESERVED_CONTEXTS, 0,
  76                         GFP_KERNEL);
  77         mutex_unlock(&dev->struct_mutex);
  78         return ret;
  79 }
  80
  81 /**
  82  * Context bitmap initialization.
  83  *
  84  * \param dev DRM device.
  85  *
  86  * Initialise the drm_device::ctx_idr
  87  */
  88 int drm_legacy_ctxbitmap_init(struct drm_device * dev)
  89 {
  90         idr_init(&dev->ctx_idr);
  91         return 0;
  92 }
  93
  94 /**
  95  * Context bitmap cleanup.
  96  *
  97  * \param dev DRM device.
  98  *
  99  * Free all idr members using drm_ctx_sarea_free helper function
 100  * while holding the drm_device::struct_mutex lock.
 101  */
 102 void drm_legacy_ctxbitmap_cleanup(struct drm_device * dev)
 103 {
 104         mutex_lock(&dev->struct_mutex);
 105         idr_destroy(&dev->ctx_idr);
 106         mutex_unlock(&dev->struct_mutex);
 107 }
 108
 109 /**
 110  * drm_ctxbitmap_flush() - Flush all contexts owned by a file
 111  * @dev: DRM device to operate on
 112  * @file: Open file to flush contexts for
 113  *
 114  * This iterates over all contexts on @dev and drops them if they're owned by
 115  * @file. Note that after this call returns, new contexts might be added if
 116  * the file is still alive.
 117  */
 118 void drm_legacy_ctxbitmap_flush(struct drm_device *dev, struct drm_file *file)
 119 {
 120         struct drm_ctx_list *pos, *tmp;
 121
 122         mutex_lock(&dev->ctxlist_mutex);
 123
 124         list_for_each_entry_safe(pos, tmp, &dev->ctxlist, head) {
 125                 if (pos->tag == file &&
 126                     pos->handle != DRM_KERNEL_CONTEXT) {
 127                         if (dev->driver->context_dtor)
 128                                 dev->driver->context_dtor(dev, pos->handle);
 129
 130                         drm_legacy_ctxbitmap_free(dev, pos->handle);
 131                         list_del(&pos->head);
 132                         kfree(pos);
 133                 }
 134         }
 135
 136         mutex_unlock(&dev->ctxlist_mutex);
 137 }
 138
 139 /*@}*/
 140
 141 /******************************************************************/
 142 /** \name Per Context SAREA Support */
 143 /*@{*/
 144
 145 /**
 146  * Get per-context SAREA.
 147  *
 148  * \param inode device inode.
 149  * \param file_priv DRM file private.
 150  * \param cmd command.
 151  * \param arg user argument pointing to a drm_ctx_priv_map structure.
 152  * \return zero on success or a negative number on failure.
 153  *
 154  * Gets the map from drm_device::ctx_idr with the handle specified and
 155  * returns its handle.
 156  */
 157 int drm_legacy_getsareactx(struct drm_device *dev, void *data,
 158                            struct drm_file *file_priv)
 159 {
 160         struct drm_ctx_priv_map *request = data;
 161         struct drm_local_map *map;
 162         struct drm_map_list *_entry;
 163
 164         mutex_lock(&dev->struct_mutex);
 165
 166         map = idr_find(&dev->ctx_idr, request->ctx_id);
 167         if (!map) {
 168                 mutex_unlock(&dev->struct_mutex);
 169                 return -EINVAL;
 170         }
 171
 172         request->handle = NULL;
 173         list_for_each_entry(_entry, &dev->maplist, head) {
 174                 if (_entry->map == map) {
 175                         request->handle =
 176                             (void *)(unsigned long)_entry->user_token;
 177                         break;
 178                 }
 179         }
 180
 181         mutex_unlock(&dev->struct_mutex);
 182
 183         if (request->handle == NULL)
 184                 return -EINVAL;
 185
 186         return 0;
 187 }
 188
 189 /**
 190  * Set per-context SAREA.
 191  *
 192  * \param inode device inode.
 193  * \param file_priv DRM file private.
 194  * \param cmd command.
 195  * \param arg user argument pointing to a drm_ctx_priv_map structure.
 196  * \return zero on success or a negative number on failure.
 197  *
 198  * Searches the mapping specified in \p arg and update the entry in
 199  * drm_device::ctx_idr with it.
 200  */
 201 int drm_legacy_setsareactx(struct drm_device *dev, void *data,
 202                            struct drm_file *file_priv)
 203 {
 204         struct drm_ctx_priv_map *request = data;
 205         struct drm_local_map *map = NULL;
 206         struct drm_map_list *r_list = NULL;
 207
 208         mutex_lock(&dev->struct_mutex);
 209         list_for_each_entry(r_list, &dev->maplist, head) {
 210                 if (r_list->map
 211                     && r_list->user_token == (unsigned long) request->handle)
 212                         goto found;
 213         }
 214       bad:
 215         mutex_unlock(&dev->struct_mutex);
 216         return -EINVAL;
 217
 218       found:
 219         map = r_list->map;
 220         if (!map)
 221                 goto bad;
 222
 223         if (IS_ERR(idr_replace(&dev->ctx_idr, map, request->ctx_id)))
 224                 goto bad;
 225
 226         mutex_unlock(&dev->struct_mutex);
 227
 228         return 0;
 229 }
 230
 231 /*@}*/
 232
 233 /******************************************************************/
 234 /** \name The actual DRM context handling routines */
 235 /*@{*/
 236
 237 /**
 238  * Switch context.
 239  *
 240  * \param dev DRM device.
 241  * \param old old context handle.
 242  * \param new new context handle.
 243  * \return zero on success or a negative number on failure.
 244  *
 245  * Attempt to set drm_device::context_flag.
 246  */
 247 static int drm_context_switch(struct drm_device * dev, int old, int new)
 248 {
 249         if (test_and_set_bit(0, &dev->context_flag)) {
 250                 DRM_ERROR("Reentering -- FIXME\n");
 251                 return -EBUSY;
 252         }
 253
 254         DRM_DEBUG("Context switch from %d to %d\n", old, new);
 255
 256         if (new == dev->last_context) {
 257                 clear_bit(0, &dev->context_flag);
 258                 return 0;
 259         }
 260
 261         return 0;
 262 }
 263
 264 /**
 265  * Complete context switch.
 266  *
 267  * \param dev DRM device.
 268  * \param new new context handle.
 269  * \return zero on success or a negative number on failure.
 270  *
 271  * Updates drm_device::last_context and drm_device::last_switch. Verifies the
 272  * hardware lock is held, clears the drm_device::context_flag and wakes up
 273  * drm_device::context_wait.
 274  */
 275 static int drm_context_switch_complete(struct drm_device *dev,
 276                                        struct drm_file *file_priv, int new)
 277 {
 278         dev->last_context = new;        /* PRE/POST: This is the _only_ writer. */
 279
 280         if (!_DRM_LOCK_IS_HELD(file_priv->master->lock.hw_lock->lock)) {
 281                 DRM_ERROR("Lock isn't held after context switch\n");
 282         }
 283
 284         /* If a context switch is ever initiated
 285            when the kernel holds the lock, release
 286            that lock here. */
 287         clear_bit(0, &dev->context_flag);
 288
 289         return 0;
 290 }
 291
 292 /**
 293  * Reserve contexts.
 294  *
 295  * \param inode device inode.
 296  * \param file_priv DRM file private.
 297  * \param cmd command.
 298  * \param arg user argument pointing to a drm_ctx_res structure.
 299  * \return zero on success or a negative number on failure.
 300  */
 301 int drm_legacy_resctx(struct drm_device *dev, void *data,
 302                       struct drm_file *file_priv)
 303 {
 304         struct drm_ctx_res *res = data;
 305         struct drm_ctx ctx;
 306         int i;
 307
 308         if (res->count >= DRM_RESERVED_CONTEXTS) {
 309                 memset(&ctx, 0, sizeof(ctx));
 310                 for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
 311                         ctx.handle = i;
 312                         if (copy_to_user(&res->contexts[i], &ctx, sizeof(ctx)))
 313                                 return -EFAULT;
 314                 }
 315         }
 316         res->count = DRM_RESERVED_CONTEXTS;
 317
 318         return 0;
 319 }
 320
 321 /**
 322  * Add context.
 323  *
 324  * \param inode device inode.
 325  * \param file_priv DRM file private.
 326  * \param cmd command.
 327  * \param arg user argument pointing to a drm_ctx structure.
 328  * \return zero on success or a negative number on failure.
 329  *
 330  * Get a new handle for the context and copy to userspace.
 331  */
 332 int drm_legacy_addctx(struct drm_device *dev, void *data,
 333                       struct drm_file *file_priv)
 334 {
 335         struct drm_ctx_list *ctx_entry;
 336         struct drm_ctx *ctx = data;
 337
 338         ctx->handle = drm_legacy_ctxbitmap_next(dev);
 339         if (ctx->handle == DRM_KERNEL_CONTEXT) {
 340                 /* Skip kernel's context and get a new one. */
 341                 ctx->handle = drm_legacy_ctxbitmap_next(dev);
 342         }
 343         DRM_DEBUG("%d\n", ctx->handle);
 344         if (ctx->handle == -1) {
 345                 DRM_DEBUG("Not enough free contexts.\n");
 346                 /* Should this return -EBUSY instead? */
 347                 return -ENOMEM;
 348         }
 349
 350         ctx_entry = kmalloc(sizeof(*ctx_entry), GFP_KERNEL);
 351         if (!ctx_entry) {
 352                 DRM_DEBUG("out of memory\n");
 353                 return -ENOMEM;
 354         }
 355
 356         INIT_LIST_HEAD(&ctx_entry->head);
 357         ctx_entry->handle = ctx->handle;
 358         ctx_entry->tag = file_priv;
 359
 360         mutex_lock(&dev->ctxlist_mutex);
 361         list_add(&ctx_entry->head, &dev->ctxlist);
 362         mutex_unlock(&dev->ctxlist_mutex);
 363
 364         return 0;
 365 }
 366
 367 /**
 368  * Get context.
 369  *
 370  * \param inode device inode.
 371  * \param file_priv DRM file private.
 372  * \param cmd command.
 373  * \param arg user argument pointing to a drm_ctx structure.
 374  * \return zero on success or a negative number on failure.
 375  */
 376 int drm_legacy_getctx(struct drm_device *dev, void *data,
 377                       struct drm_file *file_priv)
 378 {
 379         struct drm_ctx *ctx = data;
 380
 381         /* This is 0, because we don't handle any context flags */
 382         ctx->flags = 0;
 383
 384         return 0;
 385 }
 386
 387 /**
 388  * Switch context.
 389  *
 390  * \param inode device inode.
 391  * \param file_priv DRM file private.
 392  * \param cmd command.
 393  * \param arg user argument pointing to a drm_ctx structure.
 394  * \return zero on success or a negative number on failure.
 395  *
 396  * Calls context_switch().
 397  */
 398 int drm_legacy_switchctx(struct drm_device *dev, void *data,
 399                          struct drm_file *file_priv)
 400 {
 401         struct drm_ctx *ctx = data;
 402
 403         DRM_DEBUG("%d\n", ctx->handle);
 404         return drm_context_switch(dev, dev->last_context, ctx->handle);
 405 }
 406
 407 /**
 408  * New context.
 409  *
 410  * \param inode device inode.
 411  * \param file_priv DRM file private.
 412  * \param cmd command.
 413  * \param arg user argument pointing to a drm_ctx structure.
 414  * \return zero on success or a negative number on failure.
 415  *
 416  * Calls context_switch_complete().
 417  */
 418 int drm_legacy_newctx(struct drm_device *dev, void *data,
 419                       struct drm_file *file_priv)
 420 {
 421         struct drm_ctx *ctx = data;
 422
 423         DRM_DEBUG("%d\n", ctx->handle);
 424         drm_context_switch_complete(dev, file_priv, ctx->handle);
 425
 426         return 0;
 427 }
 428
 429 /**
 430  * Remove context.
 431  *
 432  * \param inode device inode.
 433  * \param file_priv DRM file private.
 434  * \param cmd command.
 435  * \param arg user argument pointing to a drm_ctx structure.
 436  * \return zero on success or a negative number on failure.
 437  *
 438  * If not the special kernel context, calls ctxbitmap_free() to free the specified context.
 439  */
 440 int drm_legacy_rmctx(struct drm_device *dev, void *data,
 441                      struct drm_file *file_priv)
 442 {
 443         struct drm_ctx *ctx = data;
 444
 445         DRM_DEBUG("%d\n", ctx->handle);
 446         if (ctx->handle != DRM_KERNEL_CONTEXT) {
 447                 if (dev->driver->context_dtor)
 448                         dev->driver->context_dtor(dev, ctx->handle);
 449                 drm_legacy_ctxbitmap_free(dev, ctx->handle);
 450         }
 451
 452         mutex_lock(&dev->ctxlist_mutex);
 453         if (!list_empty(&dev->ctxlist)) {
 454                 struct drm_ctx_list *pos, *n;
 455
 456                 list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
 457                         if (pos->handle == ctx->handle) {
 458                                 list_del(&pos->head);
 459                                 kfree(pos);
 460                         }
 461                 }
 462         }
 463         mutex_unlock(&dev->ctxlist_mutex);
 464
 465         return 0;
 466 }
 467
 468 /*@}*/