drivers/gpu/drm/drm_drv.c

   1 /**
   2  * \file drm_drv.c
   3  * Generic driver template
   4  *
   5  * \author Rickard E. (Rik) Faith <faith@valinux.com>
   6  * \author Gareth Hughes <gareth@valinux.com>
   7  *
   8  * To use this template, you must at least define the following (samples
   9  * given for the MGA driver):
  10  *
  11  * \code
  12  * #define DRIVER_AUTHOR        "VA Linux Systems, Inc."
  13  *
  14  * #define DRIVER_NAME          "mga"
  15  * #define DRIVER_DESC          "Matrox G200/G400"
  16  * #define DRIVER_DATE          "20001127"
  17  *
  18  * #define drm_x                mga_##x
  19  * \endcode
  20  */
  21
  22 /*
  23  * Created: Thu Nov 23 03:10:50 2000 by gareth@valinux.com
  24  *
  25  * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
  26  * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
  27  * All Rights Reserved.
  28  *
  29  * Permission is hereby granted, free of charge, to any person obtaining a
  30  * copy of this software and associated documentation files (the "Software"),
  31  * to deal in the Software without restriction, including without limitation
  32  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  33  * and/or sell copies of the Software, and to permit persons to whom the
  34  * Software is furnished to do so, subject to the following conditions:
  35  *
  36  * The above copyright notice and this permission notice (including the next
  37  * paragraph) shall be included in all copies or substantial portions of the
  38  * Software.
  39  *
  40  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  41  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  42  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  43  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  44  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  45  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  46  * OTHER DEALINGS IN THE SOFTWARE.
  47  */
  48
  49 #include <linux/debugfs.h>
  50 #include <linux/slab.h>
  51 #include <linux/export.h>
  52 #include <drm/drmP.h>
  53 #include <drm/drm_core.h>
  54
  55
  56 static int drm_version(struct drm_device *dev, void *data,
  57                        struct drm_file *file_priv);
  58
  59 #define DRM_IOCTL_DEF(ioctl, _func, _flags) \
  60         [DRM_IOCTL_NR(ioctl)] = {.cmd = ioctl, .func = _func, .flags = _flags, .cmd_drv = 0, .name = #ioctl}
  61
  62 /** Ioctl table */
  63 static const struct drm_ioctl_desc drm_ioctls[] = {
  64         DRM_IOCTL_DEF(DRM_IOCTL_VERSION, drm_version, DRM_UNLOCKED),
  65         DRM_IOCTL_DEF(DRM_IOCTL_GET_UNIQUE, drm_getunique, 0),
  66         DRM_IOCTL_DEF(DRM_IOCTL_GET_MAGIC, drm_getmagic, 0),
  67         DRM_IOCTL_DEF(DRM_IOCTL_IRQ_BUSID, drm_irq_by_busid, DRM_MASTER|DRM_ROOT_ONLY),
  68         DRM_IOCTL_DEF(DRM_IOCTL_GET_MAP, drm_getmap, DRM_UNLOCKED),
  69         DRM_IOCTL_DEF(DRM_IOCTL_GET_CLIENT, drm_getclient, DRM_UNLOCKED),
  70         DRM_IOCTL_DEF(DRM_IOCTL_GET_STATS, drm_getstats, DRM_UNLOCKED),
  71         DRM_IOCTL_DEF(DRM_IOCTL_GET_CAP, drm_getcap, DRM_UNLOCKED|DRM_RENDER_ALLOW),
  72         DRM_IOCTL_DEF(DRM_IOCTL_SET_VERSION, drm_setversion, DRM_MASTER),
  73
  74         DRM_IOCTL_DEF(DRM_IOCTL_SET_UNIQUE, drm_setunique, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
  75         DRM_IOCTL_DEF(DRM_IOCTL_BLOCK, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
  76         DRM_IOCTL_DEF(DRM_IOCTL_UNBLOCK, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
  77         DRM_IOCTL_DEF(DRM_IOCTL_AUTH_MAGIC, drm_authmagic, DRM_AUTH|DRM_MASTER),
  78
  79         DRM_IOCTL_DEF(DRM_IOCTL_ADD_MAP, drm_addmap_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
  80         DRM_IOCTL_DEF(DRM_IOCTL_RM_MAP, drm_rmmap_ioctl, DRM_AUTH),
  81
  82         DRM_IOCTL_DEF(DRM_IOCTL_SET_SAREA_CTX, drm_setsareactx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
  83         DRM_IOCTL_DEF(DRM_IOCTL_GET_SAREA_CTX, drm_getsareactx, DRM_AUTH),
  84
  85         DRM_IOCTL_DEF(DRM_IOCTL_SET_MASTER, drm_setmaster_ioctl, DRM_ROOT_ONLY),
  86         DRM_IOCTL_DEF(DRM_IOCTL_DROP_MASTER, drm_dropmaster_ioctl, DRM_ROOT_ONLY),
  87
  88         DRM_IOCTL_DEF(DRM_IOCTL_ADD_CTX, drm_addctx, DRM_AUTH|DRM_ROOT_ONLY),
  89         DRM_IOCTL_DEF(DRM_IOCTL_RM_CTX, drm_rmctx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
  90         DRM_IOCTL_DEF(DRM_IOCTL_MOD_CTX, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
  91         DRM_IOCTL_DEF(DRM_IOCTL_GET_CTX, drm_getctx, DRM_AUTH),
  92         DRM_IOCTL_DEF(DRM_IOCTL_SWITCH_CTX, drm_switchctx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
  93         DRM_IOCTL_DEF(DRM_IOCTL_NEW_CTX, drm_newctx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
  94         DRM_IOCTL_DEF(DRM_IOCTL_RES_CTX, drm_resctx, DRM_AUTH),
  95
  96         DRM_IOCTL_DEF(DRM_IOCTL_ADD_DRAW, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
  97         DRM_IOCTL_DEF(DRM_IOCTL_RM_DRAW, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
  98
  99         DRM_IOCTL_DEF(DRM_IOCTL_LOCK, drm_lock, DRM_AUTH),
 100         DRM_IOCTL_DEF(DRM_IOCTL_UNLOCK, drm_unlock, DRM_AUTH),
 101
 102         DRM_IOCTL_DEF(DRM_IOCTL_FINISH, drm_noop, DRM_AUTH),
 103
 104         DRM_IOCTL_DEF(DRM_IOCTL_ADD_BUFS, drm_addbufs, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
 105         DRM_IOCTL_DEF(DRM_IOCTL_MARK_BUFS, drm_markbufs, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
 106         DRM_IOCTL_DEF(DRM_IOCTL_INFO_BUFS, drm_infobufs, DRM_AUTH),
 107         DRM_IOCTL_DEF(DRM_IOCTL_MAP_BUFS, drm_mapbufs, DRM_AUTH),
 108         DRM_IOCTL_DEF(DRM_IOCTL_FREE_BUFS, drm_freebufs, DRM_AUTH),
 109         DRM_IOCTL_DEF(DRM_IOCTL_DMA, drm_dma_ioctl, DRM_AUTH),
 110
 111         DRM_IOCTL_DEF(DRM_IOCTL_CONTROL, drm_control, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
 112
 113 #if __OS_HAS_AGP
 114         DRM_IOCTL_DEF(DRM_IOCTL_AGP_ACQUIRE, drm_agp_acquire_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
 115         DRM_IOCTL_DEF(DRM_IOCTL_AGP_RELEASE, drm_agp_release_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
 116         DRM_IOCTL_DEF(DRM_IOCTL_AGP_ENABLE, drm_agp_enable_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
 117         DRM_IOCTL_DEF(DRM_IOCTL_AGP_INFO, drm_agp_info_ioctl, DRM_AUTH),
 118         DRM_IOCTL_DEF(DRM_IOCTL_AGP_ALLOC, drm_agp_alloc_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
 119         DRM_IOCTL_DEF(DRM_IOCTL_AGP_FREE, drm_agp_free_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
 120         DRM_IOCTL_DEF(DRM_IOCTL_AGP_BIND, drm_agp_bind_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
 121         DRM_IOCTL_DEF(DRM_IOCTL_AGP_UNBIND, drm_agp_unbind_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
 122 #endif
 123
 124         DRM_IOCTL_DEF(DRM_IOCTL_SG_ALLOC, drm_sg_alloc, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
 125         DRM_IOCTL_DEF(DRM_IOCTL_SG_FREE, drm_sg_free, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
 126
 127         DRM_IOCTL_DEF(DRM_IOCTL_WAIT_VBLANK, drm_wait_vblank, DRM_UNLOCKED),
 128
 129         DRM_IOCTL_DEF(DRM_IOCTL_MODESET_CTL, drm_modeset_ctl, 0),
 130
 131         DRM_IOCTL_DEF(DRM_IOCTL_UPDATE_DRAW, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
 132
 133         DRM_IOCTL_DEF(DRM_IOCTL_GEM_CLOSE, drm_gem_close_ioctl, DRM_UNLOCKED|DRM_RENDER_ALLOW),
 134         DRM_IOCTL_DEF(DRM_IOCTL_GEM_FLINK, drm_gem_flink_ioctl, DRM_AUTH|DRM_UNLOCKED),
 135         DRM_IOCTL_DEF(DRM_IOCTL_GEM_OPEN, drm_gem_open_ioctl, DRM_AUTH|DRM_UNLOCKED),
 136
 137         DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETRESOURCES, drm_mode_getresources, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 138
 139         DRM_IOCTL_DEF(DRM_IOCTL_PRIME_HANDLE_TO_FD, drm_prime_handle_to_fd_ioctl, DRM_AUTH|DRM_UNLOCKED|DRM_RENDER_ALLOW),
 140         DRM_IOCTL_DEF(DRM_IOCTL_PRIME_FD_TO_HANDLE, drm_prime_fd_to_handle_ioctl, DRM_AUTH|DRM_UNLOCKED|DRM_RENDER_ALLOW),
 141
 142         DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPLANERESOURCES, drm_mode_getplane_res, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 143         DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETCRTC, drm_mode_getcrtc, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 144         DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETCRTC, drm_mode_setcrtc, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 145         DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPLANE, drm_mode_getplane, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 146         DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETPLANE, drm_mode_setplane, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 147         DRM_IOCTL_DEF(DRM_IOCTL_MODE_CURSOR, drm_mode_cursor_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 148         DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETGAMMA, drm_mode_gamma_get_ioctl, DRM_UNLOCKED),
 149         DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETGAMMA, drm_mode_gamma_set_ioctl, DRM_MASTER|DRM_UNLOCKED),
 150         DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETENCODER, drm_mode_getencoder, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 151         DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETCONNECTOR, drm_mode_getconnector, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 152         DRM_IOCTL_DEF(DRM_IOCTL_MODE_ATTACHMODE, drm_noop, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 153         DRM_IOCTL_DEF(DRM_IOCTL_MODE_DETACHMODE, drm_noop, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 154         DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPROPERTY, drm_mode_getproperty_ioctl, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 155         DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETPROPERTY, drm_mode_connector_property_set_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 156         DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPROPBLOB, drm_mode_getblob_ioctl, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 157         DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETFB, drm_mode_getfb, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 158         DRM_IOCTL_DEF(DRM_IOCTL_MODE_ADDFB, drm_mode_addfb, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 159         DRM_IOCTL_DEF(DRM_IOCTL_MODE_ADDFB2, drm_mode_addfb2, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 160         DRM_IOCTL_DEF(DRM_IOCTL_MODE_RMFB, drm_mode_rmfb, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 161         DRM_IOCTL_DEF(DRM_IOCTL_MODE_PAGE_FLIP, drm_mode_page_flip_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 162         DRM_IOCTL_DEF(DRM_IOCTL_MODE_DIRTYFB, drm_mode_dirtyfb_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 163         DRM_IOCTL_DEF(DRM_IOCTL_MODE_CREATE_DUMB, drm_mode_create_dumb_ioctl, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 164         DRM_IOCTL_DEF(DRM_IOCTL_MODE_MAP_DUMB, drm_mode_mmap_dumb_ioctl, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 165         DRM_IOCTL_DEF(DRM_IOCTL_MODE_DESTROY_DUMB, drm_mode_destroy_dumb_ioctl, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 166         DRM_IOCTL_DEF(DRM_IOCTL_MODE_OBJ_GETPROPERTIES, drm_mode_obj_get_properties_ioctl, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 167         DRM_IOCTL_DEF(DRM_IOCTL_MODE_OBJ_SETPROPERTY, drm_mode_obj_set_property_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 168         DRM_IOCTL_DEF(DRM_IOCTL_MODE_CURSOR2, drm_mode_cursor2_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 169 };
 170
 171 #define DRM_CORE_IOCTL_COUNT    ARRAY_SIZE( drm_ioctls )
 172
 173 /**
 174  * drm_legacy_dev_reinit
 175  *
 176  * Reinitializes a legacy/ums drm device in it's lastclose function.
 177  */
 178 static void drm_legacy_dev_reinit(struct drm_device *dev)
 179 {
 180         int i;
 181
 182         if (drm_core_check_feature(dev, DRIVER_MODESET))
 183                 return;
 184
 185         atomic_set(&dev->ioctl_count, 0);
 186         atomic_set(&dev->vma_count, 0);
 187
 188         for (i = 0; i < ARRAY_SIZE(dev->counts); i++)
 189                 atomic_set(&dev->counts[i], 0);
 190
 191         dev->sigdata.lock = NULL;
 192
 193         dev->context_flag = 0;
 194         dev->last_context = 0;
 195         dev->if_version = 0;
 196 }
 197
 198 /**
 199  * Take down the DRM device.
 200  *
 201  * \param dev DRM device structure.
 202  *
 203  * Frees every resource in \p dev.
 204  *
 205  * \sa drm_device
 206  */
 207 int drm_lastclose(struct drm_device * dev)
 208 {
 209         struct drm_vma_entry *vma, *vma_temp;
 210
 211         DRM_DEBUG("\n");
 212
 213         if (dev->driver->lastclose)
 214                 dev->driver->lastclose(dev);
 215         DRM_DEBUG("driver lastclose completed\n");
 216
 217         if (dev->irq_enabled && !drm_core_check_feature(dev, DRIVER_MODESET))
 218                 drm_irq_uninstall(dev);
 219
 220         mutex_lock(&dev->struct_mutex);
 221
 222         drm_agp_clear(dev);
 223
 224         drm_legacy_sg_cleanup(dev);
 225
 226         /* Clear vma list (only built for debugging) */
 227         list_for_each_entry_safe(vma, vma_temp, &dev->vmalist, head) {
 228                 list_del(&vma->head);
 229                 kfree(vma);
 230         }
 231
 232         drm_legacy_dma_takedown(dev);
 233
 234         dev->dev_mapping = NULL;
 235         mutex_unlock(&dev->struct_mutex);
 236
 237         drm_legacy_dev_reinit(dev);
 238
 239         DRM_DEBUG("lastclose completed\n");
 240         return 0;
 241 }
 242
 243 /** File operations structure */
 244 static const struct file_operations drm_stub_fops = {
 245         .owner = THIS_MODULE,
 246         .open = drm_stub_open,
 247         .llseek = noop_llseek,
 248 };
 249
 250 static int __init drm_core_init(void)
 251 {
 252         int ret = -ENOMEM;
 253
 254         drm_global_init();
 255         drm_connector_ida_init();
 256         idr_init(&drm_minors_idr);
 257
 258         if (register_chrdev(DRM_MAJOR, "drm", &drm_stub_fops))
 259                 goto err_p1;
 260
 261         drm_class = drm_sysfs_create(THIS_MODULE, "drm");
 262         if (IS_ERR(drm_class)) {
 263                 printk(KERN_ERR "DRM: Error creating drm class.\n");
 264                 ret = PTR_ERR(drm_class);
 265                 goto err_p2;
 266         }
 267
 268         drm_debugfs_root = debugfs_create_dir("dri", NULL);
 269         if (!drm_debugfs_root) {
 270                 DRM_ERROR("Cannot create /sys/kernel/debug/dri\n");
 271                 ret = -1;
 272                 goto err_p3;
 273         }
 274
 275         DRM_INFO("Initialized %s %d.%d.%d %s\n",
 276                  CORE_NAME, CORE_MAJOR, CORE_MINOR, CORE_PATCHLEVEL, CORE_DATE);
 277         return 0;
 278 err_p3:
 279         drm_sysfs_destroy();
 280 err_p2:
 281         unregister_chrdev(DRM_MAJOR, "drm");
 282
 283         idr_destroy(&drm_minors_idr);
 284 err_p1:
 285         return ret;
 286 }
 287
 288 static void __exit drm_core_exit(void)
 289 {
 290         debugfs_remove(drm_debugfs_root);
 291         drm_sysfs_destroy();
 292
 293         unregister_chrdev(DRM_MAJOR, "drm");
 294
 295         drm_connector_ida_destroy();
 296         idr_destroy(&drm_minors_idr);
 297 }
 298
 299 module_init(drm_core_init);
 300 module_exit(drm_core_exit);
 301
 302 /**
 303  * Copy and IOCTL return string to user space
 304  */
 305 static int drm_copy_field(char *buf, size_t *buf_len, const char *value)
 306 {
 307         int len;
 308
 309         /* don't overflow userbuf */
 310         len = strlen(value);
 311         if (len > *buf_len)
 312                 len = *buf_len;
 313
 314         /* let userspace know exact length of driver value (which could be
 315          * larger than the userspace-supplied buffer) */
 316         *buf_len = strlen(value);
 317
 318         /* finally, try filling in the userbuf */
 319         if (len && buf)
 320                 if (copy_to_user(buf, value, len))
 321                         return -EFAULT;
 322         return 0;
 323 }
 324
 325 /**
 326  * Get version information
 327  *
 328  * \param inode device inode.
 329  * \param filp file pointer.
 330  * \param cmd command.
 331  * \param arg user argument, pointing to a drm_version structure.
 332  * \return zero on success or negative number on failure.
 333  *
 334  * Fills in the version information in \p arg.
 335  */
 336 static int drm_version(struct drm_device *dev, void *data,
 337                        struct drm_file *file_priv)
 338 {
 339         struct drm_version *version = data;
 340         int err;
 341
 342         version->version_major = dev->driver->major;
 343         version->version_minor = dev->driver->minor;
 344         version->version_patchlevel = dev->driver->patchlevel;
 345         err = drm_copy_field(version->name, &version->name_len,
 346                         dev->driver->name);
 347         if (!err)
 348                 err = drm_copy_field(version->date, &version->date_len,
 349                                 dev->driver->date);
 350         if (!err)
 351                 err = drm_copy_field(version->desc, &version->desc_len,
 352                                 dev->driver->desc);
 353
 354         return err;
 355 }
 356
 357 /**
 358  * Called whenever a process performs an ioctl on /dev/drm.
 359  *
 360  * \param inode device inode.
 361  * \param file_priv DRM file private.
 362  * \param cmd command.
 363  * \param arg user argument.
 364  * \return zero on success or negative number on failure.
 365  *
 366  * Looks up the ioctl function in the ::ioctls table, checking for root
 367  * previleges if so required, and dispatches to the respective function.
 368  */
 369 long drm_ioctl(struct file *filp,
 370               unsigned int cmd, unsigned long arg)
 371 {
 372         struct drm_file *file_priv = filp->private_data;
 373         struct drm_device *dev;
 374         const struct drm_ioctl_desc *ioctl = NULL;
 375         drm_ioctl_t *func;
 376         unsigned int nr = DRM_IOCTL_NR(cmd);
 377         int retcode = -EINVAL;
 378         char stack_kdata[128];
 379         char *kdata = NULL;
 380         unsigned int usize, asize;
 381
 382         dev = file_priv->minor->dev;
 383
 384         if (drm_device_is_unplugged(dev))
 385                 return -ENODEV;
 386
 387         atomic_inc(&dev->ioctl_count);
 388         atomic_inc(&dev->counts[_DRM_STAT_IOCTLS]);
 389         ++file_priv->ioctl_count;
 390
 391         if ((nr >= DRM_CORE_IOCTL_COUNT) &&
 392             ((nr < DRM_COMMAND_BASE) || (nr >= DRM_COMMAND_END)))
 393                 goto err_i1;
 394         if ((nr >= DRM_COMMAND_BASE) && (nr < DRM_COMMAND_END) &&
 395             (nr < DRM_COMMAND_BASE + dev->driver->num_ioctls)) {
 396                 u32 drv_size;
 397                 ioctl = &dev->driver->ioctls[nr - DRM_COMMAND_BASE];
 398                 drv_size = _IOC_SIZE(ioctl->cmd_drv);
 399                 usize = asize = _IOC_SIZE(cmd);
 400                 if (drv_size > asize)
 401                         asize = drv_size;
 402                 cmd = ioctl->cmd_drv;
 403         }
 404         else if ((nr >= DRM_COMMAND_END) || (nr < DRM_COMMAND_BASE)) {
 405                 ioctl = &drm_ioctls[nr];
 406                 cmd = ioctl->cmd;
 407                 usize = asize = _IOC_SIZE(cmd);
 408         } else
 409                 goto err_i1;
 410
 411         DRM_DEBUG("pid=%d, dev=0x%lx, auth=%d, %s\n",
 412                   task_pid_nr(current),
 413                   (long)old_encode_dev(file_priv->minor->device),
 414                   file_priv->authenticated, ioctl->name);
 415
 416         /* Do not trust userspace, use our own definition */
 417         func = ioctl->func;
 418
 419         if (!func) {
 420                 DRM_DEBUG("no function\n");
 421                 retcode = -EINVAL;
 422         } else if (((ioctl->flags & DRM_ROOT_ONLY) && !capable(CAP_SYS_ADMIN)) ||
 423                    ((ioctl->flags & DRM_AUTH) && !drm_is_render_client(file_priv) && !file_priv->authenticated) ||
 424                    ((ioctl->flags & DRM_MASTER) && !file_priv->is_master) ||
 425                    (!(ioctl->flags & DRM_CONTROL_ALLOW) && (file_priv->minor->type == DRM_MINOR_CONTROL)) ||
 426                    (!(ioctl->flags & DRM_RENDER_ALLOW) && drm_is_render_client(file_priv))) {
 427                 retcode = -EACCES;
 428         } else {
 429                 if (cmd & (IOC_IN | IOC_OUT)) {
 430                         if (asize <= sizeof(stack_kdata)) {
 431                                 kdata = stack_kdata;
 432                         } else {
 433                                 kdata = kmalloc(asize, GFP_KERNEL);
 434                                 if (!kdata) {
 435                                         retcode = -ENOMEM;
 436                                         goto err_i1;
 437                                 }
 438                         }
 439                         if (asize > usize)
 440                                 memset(kdata + usize, 0, asize - usize);
 441                 }
 442
 443                 if (cmd & IOC_IN) {
 444                         if (copy_from_user(kdata, (void __user *)arg,
 445                                            usize) != 0) {
 446                                 retcode = -EFAULT;
 447                                 goto err_i1;
 448                         }
 449                 } else
 450                         memset(kdata, 0, usize);
 451
 452                 if (ioctl->flags & DRM_UNLOCKED)
 453                         retcode = func(dev, kdata, file_priv);
 454                 else {
 455                         mutex_lock(&drm_global_mutex);
 456                         retcode = func(dev, kdata, file_priv);
 457                         mutex_unlock(&drm_global_mutex);
 458                 }
 459
 460                 if (cmd & IOC_OUT) {
 461                         if (copy_to_user((void __user *)arg, kdata,
 462                                          usize) != 0)
 463                                 retcode = -EFAULT;
 464                 }
 465         }
 466
 467       err_i1:
 468         if (!ioctl)
 469                 DRM_DEBUG("invalid iotcl: pid=%d, dev=0x%lx, auth=%d, cmd=0x%02x, nr=0x%02x\n",
 470                           task_pid_nr(current),
 471                           (long)old_encode_dev(file_priv->minor->device),
 472                           file_priv->authenticated, cmd, nr);
 473
 474         if (kdata != stack_kdata)
 475                 kfree(kdata);
 476         atomic_dec(&dev->ioctl_count);
 477         if (retcode)
 478                 DRM_DEBUG("ret = %d\n", retcode);
 479         return retcode;
 480 }
 481 EXPORT_SYMBOL(drm_ioctl);