1 /*
2  * Created: Fri Jan  8 09:01:26 1999 by faith@valinux.com
3  *
4  * Copyright 1999 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 <linux/export.h>
32 #include <linux/nospec.h>
33 #include <linux/pci.h>
34 #include <linux/uaccess.h>
35 
36 #include <drm/drm_agpsupport.h>
37 #include <drm/drm_auth.h>
38 #include <drm/drm_crtc.h>
39 #include <drm/drm_drv.h>
40 #include <drm/drm_file.h>
41 #include <drm/drm_ioctl.h>
42 #include <drm/drm_print.h>
43 
44 #include "drm_crtc_internal.h"
45 #include "drm_internal.h"
46 #include "drm_legacy.h"
47 
48 /**
49  * DOC: getunique and setversion story
50  *
51  * BEWARE THE DRAGONS! MIND THE TRAPDOORS!
52  *
53  * In an attempt to warn anyone else who's trying to figure out what's going
54  * on here, I'll try to summarize the story. First things first, let's clear up
55  * the names, because the kernel internals, libdrm and the ioctls are all named
56  * differently:
57  *
58  *  - GET_UNIQUE ioctl, implemented by drm_getunique is wrapped up in libdrm
59  *    through the drmGetBusid function.
60  *  - The libdrm drmSetBusid function is backed by the SET_UNIQUE ioctl. All
61  *    that code is nerved in the kernel with drm_invalid_op().
62  *  - The internal set_busid kernel functions and driver callbacks are
63  *    exclusively use by the SET_VERSION ioctl, because only drm 1.0 (which is
64  *    nerved) allowed userspace to set the busid through the above ioctl.
65  *  - Other ioctls and functions involved are named consistently.
66  *
67  * For anyone wondering what's the difference between drm 1.1 and 1.4: Correctly
68  * handling pci domains in the busid on ppc. Doing this correctly was only
69  * implemented in libdrm in 2010, hence can't be nerved yet. No one knows what's
70  * special with drm 1.2 and 1.3.
71  *
72  * Now the actual horror story of how device lookup in drm works. At large,
73  * there's 2 different ways, either by busid, or by device driver name.
74  *
75  * Opening by busid is fairly simple:
76  *
77  * 1. First call SET_VERSION to make sure pci domains are handled properly. As a
78  *    side-effect this fills out the unique name in the master structure.
79  * 2. Call GET_UNIQUE to read out the unique name from the master structure,
80  *    which matches the busid thanks to step 1. If it doesn't, proceed to try
81  *    the next device node.
82  *
83  * Opening by name is slightly different:
84  *
85  * 1. Directly call VERSION to get the version and to match against the driver
86  *    name returned by that ioctl. Note that SET_VERSION is not called, which
87  *    means the the unique name for the master node just opening is _not_ filled
88  *    out. This despite that with current drm device nodes are always bound to
89  *    one device, and can't be runtime assigned like with drm 1.0.
90  * 2. Match driver name. If it mismatches, proceed to the next device node.
91  * 3. Call GET_UNIQUE, and check whether the unique name has length zero (by
92  *    checking that the first byte in the string is 0). If that's not the case
93  *    libdrm skips and proceeds to the next device node. Probably this is just
94  *    copypasta from drm 1.0 times where a set unique name meant that the driver
95  *    was in use already, but that's just conjecture.
96  *
97  * Long story short: To keep the open by name logic working, GET_UNIQUE must
98  * _not_ return a unique string when SET_VERSION hasn't been called yet,
99  * otherwise libdrm breaks. Even when that unique string can't ever change, and
100  * is totally irrelevant for actually opening the device because runtime
101  * assignable device instances were only support in drm 1.0, which is long dead.
102  * But the libdrm code in drmOpenByName somehow survived, hence this can't be
103  * broken.
104  */
105 
106 /*
107  * Get the bus id.
108  *
109  * \param inode device inode.
110  * \param file_priv DRM file private.
111  * \param cmd command.
112  * \param arg user argument, pointing to a drm_unique structure.
113  * \return zero on success or a negative number on failure.
114  *
115  * Copies the bus id from drm_device::unique into user space.
116  */
drm_getunique(struct drm_device * dev,void * data,struct drm_file * file_priv)117 int drm_getunique(struct drm_device *dev, void *data,
118 		  struct drm_file *file_priv)
119 {
120 	struct drm_unique *u = data;
121 	struct drm_master *master = file_priv->master;
122 
123 	mutex_lock(&master->dev->master_mutex);
124 	if (u->unique_len >= master->unique_len) {
125 		if (copy_to_user(u->unique, master->unique, master->unique_len)) {
126 			mutex_unlock(&master->dev->master_mutex);
127 			return -EFAULT;
128 		}
129 	}
130 	u->unique_len = master->unique_len;
131 	mutex_unlock(&master->dev->master_mutex);
132 
133 	return 0;
134 }
135 
136 static void
drm_unset_busid(struct drm_device * dev,struct drm_master * master)137 drm_unset_busid(struct drm_device *dev,
138 		struct drm_master *master)
139 {
140 	kfree(master->unique);
141 	master->unique = NULL;
142 	master->unique_len = 0;
143 }
144 
drm_set_busid(struct drm_device * dev,struct drm_file * file_priv)145 static int drm_set_busid(struct drm_device *dev, struct drm_file *file_priv)
146 {
147 	struct drm_master *master = file_priv->master;
148 	int ret;
149 
150 	if (master->unique != NULL)
151 		drm_unset_busid(dev, master);
152 
153 	if (dev->dev && dev_is_pci(dev->dev)) {
154 		ret = drm_pci_set_busid(dev, master);
155 		if (ret) {
156 			drm_unset_busid(dev, master);
157 			return ret;
158 		}
159 	} else {
160 		WARN_ON(!dev->unique);
161 		master->unique = kstrdup(dev->unique, GFP_KERNEL);
162 		if (master->unique)
163 			master->unique_len = strlen(dev->unique);
164 	}
165 
166 	return 0;
167 }
168 
169 /*
170  * Get client information.
171  *
172  * \param inode device inode.
173  * \param file_priv DRM file private.
174  * \param cmd command.
175  * \param arg user argument, pointing to a drm_client structure.
176  *
177  * \return zero on success or a negative number on failure.
178  *
179  * Searches for the client with the specified index and copies its information
180  * into userspace
181  */
drm_getclient(struct drm_device * dev,void * data,struct drm_file * file_priv)182 int drm_getclient(struct drm_device *dev, void *data,
183 		  struct drm_file *file_priv)
184 {
185 	struct drm_client *client = data;
186 
187 	/*
188 	 * Hollowed-out getclient ioctl to keep some dead old drm tests/tools
189 	 * not breaking completely. Userspace tools stop enumerating one they
190 	 * get -EINVAL, hence this is the return value we need to hand back for
191 	 * no clients tracked.
192 	 *
193 	 * Unfortunately some clients (*cough* libva *cough*) use this in a fun
194 	 * attempt to figure out whether they're authenticated or not. Since
195 	 * that's the only thing they care about, give it to the directly
196 	 * instead of walking one giant list.
197 	 */
198 	if (client->idx == 0) {
199 		client->auth = file_priv->authenticated;
200 		client->pid = task_pid_vnr(current);
201 		client->uid = overflowuid;
202 		client->magic = 0;
203 		client->iocs = 0;
204 
205 		return 0;
206 	} else {
207 		return -EINVAL;
208 	}
209 }
210 
211 /*
212  * Get statistics information.
213  *
214  * \param inode device inode.
215  * \param file_priv DRM file private.
216  * \param cmd command.
217  * \param arg user argument, pointing to a drm_stats structure.
218  *
219  * \return zero on success or a negative number on failure.
220  */
drm_getstats(struct drm_device * dev,void * data,struct drm_file * file_priv)221 static int drm_getstats(struct drm_device *dev, void *data,
222 		 struct drm_file *file_priv)
223 {
224 	struct drm_stats *stats = data;
225 
226 	/* Clear stats to prevent userspace from eating its stack garbage. */
227 	memset(stats, 0, sizeof(*stats));
228 
229 	return 0;
230 }
231 
232 /*
233  * Get device/driver capabilities
234  */
drm_getcap(struct drm_device * dev,void * data,struct drm_file * file_priv)235 static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_priv)
236 {
237 	struct drm_get_cap *req = data;
238 	struct drm_crtc *crtc;
239 
240 	req->value = 0;
241 
242 	/* Only some caps make sense with UMS/render-only drivers. */
243 	switch (req->capability) {
244 	case DRM_CAP_TIMESTAMP_MONOTONIC:
245 		req->value = 1;
246 		return 0;
247 	case DRM_CAP_PRIME:
248 		req->value |= dev->driver->prime_fd_to_handle ? DRM_PRIME_CAP_IMPORT : 0;
249 		req->value |= dev->driver->prime_handle_to_fd ? DRM_PRIME_CAP_EXPORT : 0;
250 		return 0;
251 	case DRM_CAP_SYNCOBJ:
252 		req->value = drm_core_check_feature(dev, DRIVER_SYNCOBJ);
253 		return 0;
254 	case DRM_CAP_SYNCOBJ_TIMELINE:
255 		req->value = drm_core_check_feature(dev, DRIVER_SYNCOBJ_TIMELINE);
256 		return 0;
257 	}
258 
259 	/* Other caps only work with KMS drivers */
260 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
261 		return -EOPNOTSUPP;
262 
263 	switch (req->capability) {
264 	case DRM_CAP_DUMB_BUFFER:
265 		if (dev->driver->dumb_create)
266 			req->value = 1;
267 		break;
268 	case DRM_CAP_VBLANK_HIGH_CRTC:
269 		req->value = 1;
270 		break;
271 	case DRM_CAP_DUMB_PREFERRED_DEPTH:
272 		req->value = dev->mode_config.preferred_depth;
273 		break;
274 	case DRM_CAP_DUMB_PREFER_SHADOW:
275 		req->value = dev->mode_config.prefer_shadow;
276 		break;
277 	case DRM_CAP_ASYNC_PAGE_FLIP:
278 		req->value = dev->mode_config.async_page_flip;
279 		break;
280 	case DRM_CAP_PAGE_FLIP_TARGET:
281 		req->value = 1;
282 		drm_for_each_crtc(crtc, dev) {
283 			if (!crtc->funcs->page_flip_target)
284 				req->value = 0;
285 		}
286 		break;
287 	case DRM_CAP_CURSOR_WIDTH:
288 		if (dev->mode_config.cursor_width)
289 			req->value = dev->mode_config.cursor_width;
290 		else
291 			req->value = 64;
292 		break;
293 	case DRM_CAP_CURSOR_HEIGHT:
294 		if (dev->mode_config.cursor_height)
295 			req->value = dev->mode_config.cursor_height;
296 		else
297 			req->value = 64;
298 		break;
299 	case DRM_CAP_ADDFB2_MODIFIERS:
300 		req->value = dev->mode_config.allow_fb_modifiers;
301 		break;
302 	case DRM_CAP_CRTC_IN_VBLANK_EVENT:
303 		req->value = 1;
304 		break;
305 	default:
306 		return -EINVAL;
307 	}
308 	return 0;
309 }
310 
311 /*
312  * Set device/driver capabilities
313  */
314 static int
drm_setclientcap(struct drm_device * dev,void * data,struct drm_file * file_priv)315 drm_setclientcap(struct drm_device *dev, void *data, struct drm_file *file_priv)
316 {
317 	struct drm_set_client_cap *req = data;
318 
319 	/* No render-only settable capabilities for now */
320 
321 	/* Below caps that only works with KMS drivers */
322 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
323 		return -EOPNOTSUPP;
324 
325 	switch (req->capability) {
326 	case DRM_CLIENT_CAP_STEREO_3D:
327 		if (req->value > 1)
328 			return -EINVAL;
329 		file_priv->stereo_allowed = req->value;
330 		break;
331 	case DRM_CLIENT_CAP_UNIVERSAL_PLANES:
332 		if (req->value > 1)
333 			return -EINVAL;
334 		file_priv->universal_planes = req->value;
335 		break;
336 	case DRM_CLIENT_CAP_ATOMIC:
337 		if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
338 			return -EOPNOTSUPP;
339 		/* The modesetting DDX has a totally broken idea of atomic. */
340 		if (current->comm[0] == 'X' && req->value == 1) {
341 			pr_info("broken atomic modeset userspace detected, disabling atomic\n");
342 			return -EOPNOTSUPP;
343 		}
344 		if (req->value > 2)
345 			return -EINVAL;
346 		file_priv->atomic = req->value;
347 		file_priv->universal_planes = req->value;
348 		/*
349 		 * No atomic user-space blows up on aspect ratio mode bits.
350 		 */
351 		file_priv->aspect_ratio_allowed = req->value;
352 		break;
353 	case DRM_CLIENT_CAP_ASPECT_RATIO:
354 		if (req->value > 1)
355 			return -EINVAL;
356 		file_priv->aspect_ratio_allowed = req->value;
357 		break;
358 	case DRM_CLIENT_CAP_WRITEBACK_CONNECTORS:
359 		if (!file_priv->atomic)
360 			return -EINVAL;
361 		if (req->value > 1)
362 			return -EINVAL;
363 		file_priv->writeback_connectors = req->value;
364 		break;
365 	default:
366 		return -EINVAL;
367 	}
368 
369 	return 0;
370 }
371 
372 /*
373  * Setversion ioctl.
374  *
375  * \param inode device inode.
376  * \param file_priv DRM file private.
377  * \param cmd command.
378  * \param arg user argument, pointing to a drm_lock structure.
379  * \return zero on success or negative number on failure.
380  *
381  * Sets the requested interface version
382  */
drm_setversion(struct drm_device * dev,void * data,struct drm_file * file_priv)383 static int drm_setversion(struct drm_device *dev, void *data, struct drm_file *file_priv)
384 {
385 	struct drm_set_version *sv = data;
386 	int if_version, retcode = 0;
387 
388 	mutex_lock(&dev->master_mutex);
389 	if (sv->drm_di_major != -1) {
390 		if (sv->drm_di_major != DRM_IF_MAJOR ||
391 		    sv->drm_di_minor < 0 || sv->drm_di_minor > DRM_IF_MINOR) {
392 			retcode = -EINVAL;
393 			goto done;
394 		}
395 		if_version = DRM_IF_VERSION(sv->drm_di_major,
396 					    sv->drm_di_minor);
397 		dev->if_version = max(if_version, dev->if_version);
398 		if (sv->drm_di_minor >= 1) {
399 			/*
400 			 * Version 1.1 includes tying of DRM to specific device
401 			 * Version 1.4 has proper PCI domain support
402 			 */
403 			retcode = drm_set_busid(dev, file_priv);
404 			if (retcode)
405 				goto done;
406 		}
407 	}
408 
409 	if (sv->drm_dd_major != -1) {
410 		if (sv->drm_dd_major != dev->driver->major ||
411 		    sv->drm_dd_minor < 0 || sv->drm_dd_minor >
412 		    dev->driver->minor) {
413 			retcode = -EINVAL;
414 			goto done;
415 		}
416 	}
417 
418 done:
419 	sv->drm_di_major = DRM_IF_MAJOR;
420 	sv->drm_di_minor = DRM_IF_MINOR;
421 	sv->drm_dd_major = dev->driver->major;
422 	sv->drm_dd_minor = dev->driver->minor;
423 	mutex_unlock(&dev->master_mutex);
424 
425 	return retcode;
426 }
427 
428 /**
429  * drm_noop - DRM no-op ioctl implemntation
430  * @dev: DRM device for the ioctl
431  * @data: data pointer for the ioctl
432  * @file_priv: DRM file for the ioctl call
433  *
434  * This no-op implementation for drm ioctls is useful for deprecated
435  * functionality where we can't return a failure code because existing userspace
436  * checks the result of the ioctl, but doesn't care about the action.
437  *
438  * Always returns successfully with 0.
439  */
drm_noop(struct drm_device * dev,void * data,struct drm_file * file_priv)440 int drm_noop(struct drm_device *dev, void *data,
441 	     struct drm_file *file_priv)
442 {
443 	DRM_DEBUG("\n");
444 	return 0;
445 }
446 EXPORT_SYMBOL(drm_noop);
447 
448 /**
449  * drm_invalid_op - DRM invalid ioctl implemntation
450  * @dev: DRM device for the ioctl
451  * @data: data pointer for the ioctl
452  * @file_priv: DRM file for the ioctl call
453  *
454  * This no-op implementation for drm ioctls is useful for deprecated
455  * functionality where we really don't want to allow userspace to call the ioctl
456  * any more. This is the case for old ums interfaces for drivers that
457  * transitioned to kms gradually and so kept the old legacy tables around. This
458  * only applies to radeon and i915 kms drivers, other drivers shouldn't need to
459  * use this function.
460  *
461  * Always fails with a return value of -EINVAL.
462  */
drm_invalid_op(struct drm_device * dev,void * data,struct drm_file * file_priv)463 int drm_invalid_op(struct drm_device *dev, void *data,
464 		   struct drm_file *file_priv)
465 {
466 	return -EINVAL;
467 }
468 EXPORT_SYMBOL(drm_invalid_op);
469 
470 /*
471  * Copy and IOCTL return string to user space
472  */
drm_copy_field(char __user * buf,size_t * buf_len,const char * value)473 static int drm_copy_field(char __user *buf, size_t *buf_len, const char *value)
474 {
475 	int len;
476 
477 	/* don't overflow userbuf */
478 	len = strlen(value);
479 	if (len > *buf_len)
480 		len = *buf_len;
481 
482 	/* let userspace know exact length of driver value (which could be
483 	 * larger than the userspace-supplied buffer) */
484 	*buf_len = strlen(value);
485 
486 	/* finally, try filling in the userbuf */
487 	if (len && buf)
488 		if (copy_to_user(buf, value, len))
489 			return -EFAULT;
490 	return 0;
491 }
492 
493 /*
494  * Get version information
495  *
496  * \param inode device inode.
497  * \param filp file pointer.
498  * \param cmd command.
499  * \param arg user argument, pointing to a drm_version structure.
500  * \return zero on success or negative number on failure.
501  *
502  * Fills in the version information in \p arg.
503  */
drm_version(struct drm_device * dev,void * data,struct drm_file * file_priv)504 int drm_version(struct drm_device *dev, void *data,
505 		       struct drm_file *file_priv)
506 {
507 	struct drm_version *version = data;
508 	int err;
509 
510 	version->version_major = dev->driver->major;
511 	version->version_minor = dev->driver->minor;
512 	version->version_patchlevel = dev->driver->patchlevel;
513 	err = drm_copy_field(version->name, &version->name_len,
514 			dev->driver->name);
515 	if (!err)
516 		err = drm_copy_field(version->date, &version->date_len,
517 				dev->driver->date);
518 	if (!err)
519 		err = drm_copy_field(version->desc, &version->desc_len,
520 				dev->driver->desc);
521 
522 	return err;
523 }
524 
525 /**
526  * drm_ioctl_permit - Check ioctl permissions against caller
527  *
528  * @flags: ioctl permission flags.
529  * @file_priv: Pointer to struct drm_file identifying the caller.
530  *
531  * Checks whether the caller is allowed to run an ioctl with the
532  * indicated permissions.
533  *
534  * Returns:
535  * Zero if allowed, -EACCES otherwise.
536  */
drm_ioctl_permit(u32 flags,struct drm_file * file_priv)537 int drm_ioctl_permit(u32 flags, struct drm_file *file_priv)
538 {
539 	/* ROOT_ONLY is only for CAP_SYS_ADMIN */
540 	if (unlikely((flags & DRM_ROOT_ONLY) && !capable(CAP_SYS_ADMIN)))
541 		return -EACCES;
542 
543 	/* AUTH is only for authenticated or render client */
544 	if (unlikely((flags & DRM_AUTH) && !drm_is_render_client(file_priv) &&
545 		     !file_priv->authenticated))
546 		return -EACCES;
547 
548 	/* MASTER is only for master or control clients */
549 	if (unlikely((flags & DRM_MASTER) &&
550 		     !drm_is_current_master(file_priv)))
551 		return -EACCES;
552 
553 	/* Render clients must be explicitly allowed */
554 	if (unlikely(!(flags & DRM_RENDER_ALLOW) &&
555 		     drm_is_render_client(file_priv)))
556 		return -EACCES;
557 
558 	return 0;
559 }
560 EXPORT_SYMBOL(drm_ioctl_permit);
561 
562 #define DRM_IOCTL_DEF(ioctl, _func, _flags)	\
563 	[DRM_IOCTL_NR(ioctl)] = {		\
564 		.cmd = ioctl,			\
565 		.func = _func,			\
566 		.flags = _flags,		\
567 		.name = #ioctl			\
568 	}
569 
570 #if IS_ENABLED(CONFIG_DRM_LEGACY)
571 #define DRM_LEGACY_IOCTL_DEF(ioctl, _func, _flags)  DRM_IOCTL_DEF(ioctl, _func, _flags)
572 #else
573 #define DRM_LEGACY_IOCTL_DEF(ioctl, _func, _flags) DRM_IOCTL_DEF(ioctl, drm_invalid_op, _flags)
574 #endif
575 
576 /* Ioctl table */
577 static const struct drm_ioctl_desc drm_ioctls[] = {
578 	DRM_IOCTL_DEF(DRM_IOCTL_VERSION, drm_version, DRM_RENDER_ALLOW),
579 	DRM_IOCTL_DEF(DRM_IOCTL_GET_UNIQUE, drm_getunique, 0),
580 	DRM_IOCTL_DEF(DRM_IOCTL_GET_MAGIC, drm_getmagic, 0),
581 	DRM_IOCTL_DEF(DRM_IOCTL_IRQ_BUSID, drm_legacy_irq_by_busid, DRM_MASTER|DRM_ROOT_ONLY),
582 
583 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_GET_MAP, drm_legacy_getmap_ioctl, 0),
584 
585 	DRM_IOCTL_DEF(DRM_IOCTL_GET_CLIENT, drm_getclient, 0),
586 	DRM_IOCTL_DEF(DRM_IOCTL_GET_STATS, drm_getstats, 0),
587 	DRM_IOCTL_DEF(DRM_IOCTL_GET_CAP, drm_getcap, DRM_RENDER_ALLOW),
588 	DRM_IOCTL_DEF(DRM_IOCTL_SET_CLIENT_CAP, drm_setclientcap, 0),
589 	DRM_IOCTL_DEF(DRM_IOCTL_SET_VERSION, drm_setversion, DRM_MASTER),
590 
591 	DRM_IOCTL_DEF(DRM_IOCTL_SET_UNIQUE, drm_invalid_op, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
592 	DRM_IOCTL_DEF(DRM_IOCTL_BLOCK, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
593 	DRM_IOCTL_DEF(DRM_IOCTL_UNBLOCK, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
594 	DRM_IOCTL_DEF(DRM_IOCTL_AUTH_MAGIC, drm_authmagic, DRM_MASTER),
595 
596 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_ADD_MAP, drm_legacy_addmap_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
597 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_RM_MAP, drm_legacy_rmmap_ioctl, DRM_AUTH),
598 
599 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_SET_SAREA_CTX, drm_legacy_setsareactx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
600 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_GET_SAREA_CTX, drm_legacy_getsareactx, DRM_AUTH),
601 
602 	DRM_IOCTL_DEF(DRM_IOCTL_SET_MASTER, drm_setmaster_ioctl, 0),
603 	DRM_IOCTL_DEF(DRM_IOCTL_DROP_MASTER, drm_dropmaster_ioctl, 0),
604 
605 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_ADD_CTX, drm_legacy_addctx, DRM_AUTH|DRM_ROOT_ONLY),
606 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_RM_CTX, drm_legacy_rmctx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
607 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_MOD_CTX, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
608 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_GET_CTX, drm_legacy_getctx, DRM_AUTH),
609 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_SWITCH_CTX, drm_legacy_switchctx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
610 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_NEW_CTX, drm_legacy_newctx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
611 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_RES_CTX, drm_legacy_resctx, DRM_AUTH),
612 
613 	DRM_IOCTL_DEF(DRM_IOCTL_ADD_DRAW, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
614 	DRM_IOCTL_DEF(DRM_IOCTL_RM_DRAW, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
615 
616 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_LOCK, drm_legacy_lock, DRM_AUTH),
617 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_UNLOCK, drm_legacy_unlock, DRM_AUTH),
618 
619 	DRM_IOCTL_DEF(DRM_IOCTL_FINISH, drm_noop, DRM_AUTH),
620 
621 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_ADD_BUFS, drm_legacy_addbufs, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
622 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_MARK_BUFS, drm_legacy_markbufs, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
623 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_INFO_BUFS, drm_legacy_infobufs, DRM_AUTH),
624 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_MAP_BUFS, drm_legacy_mapbufs, DRM_AUTH),
625 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_FREE_BUFS, drm_legacy_freebufs, DRM_AUTH),
626 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_DMA, drm_legacy_dma_ioctl, DRM_AUTH),
627 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_CONTROL, drm_legacy_irq_control, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
628 
629 #if IS_ENABLED(CONFIG_AGP)
630 	DRM_IOCTL_DEF(DRM_IOCTL_AGP_ACQUIRE, drm_agp_acquire_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
631 	DRM_IOCTL_DEF(DRM_IOCTL_AGP_RELEASE, drm_agp_release_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
632 	DRM_IOCTL_DEF(DRM_IOCTL_AGP_ENABLE, drm_agp_enable_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
633 	DRM_IOCTL_DEF(DRM_IOCTL_AGP_INFO, drm_agp_info_ioctl, DRM_AUTH),
634 	DRM_IOCTL_DEF(DRM_IOCTL_AGP_ALLOC, drm_agp_alloc_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
635 	DRM_IOCTL_DEF(DRM_IOCTL_AGP_FREE, drm_agp_free_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
636 	DRM_IOCTL_DEF(DRM_IOCTL_AGP_BIND, drm_agp_bind_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
637 	DRM_IOCTL_DEF(DRM_IOCTL_AGP_UNBIND, drm_agp_unbind_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
638 #endif
639 
640 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_SG_ALLOC, drm_legacy_sg_alloc, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
641 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_SG_FREE, drm_legacy_sg_free, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
642 
643 	DRM_IOCTL_DEF(DRM_IOCTL_WAIT_VBLANK, drm_wait_vblank_ioctl, DRM_UNLOCKED),
644 
645 	DRM_IOCTL_DEF(DRM_IOCTL_MODESET_CTL, drm_legacy_modeset_ctl_ioctl, 0),
646 
647 	DRM_IOCTL_DEF(DRM_IOCTL_UPDATE_DRAW, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
648 
649 	DRM_IOCTL_DEF(DRM_IOCTL_GEM_CLOSE, drm_gem_close_ioctl, DRM_RENDER_ALLOW),
650 	DRM_IOCTL_DEF(DRM_IOCTL_GEM_FLINK, drm_gem_flink_ioctl, DRM_AUTH),
651 	DRM_IOCTL_DEF(DRM_IOCTL_GEM_OPEN, drm_gem_open_ioctl, DRM_AUTH),
652 
653 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETRESOURCES, drm_mode_getresources, 0),
654 
655 	DRM_IOCTL_DEF(DRM_IOCTL_PRIME_HANDLE_TO_FD, drm_prime_handle_to_fd_ioctl, DRM_RENDER_ALLOW),
656 	DRM_IOCTL_DEF(DRM_IOCTL_PRIME_FD_TO_HANDLE, drm_prime_fd_to_handle_ioctl, DRM_RENDER_ALLOW),
657 
658 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPLANERESOURCES, drm_mode_getplane_res, 0),
659 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETCRTC, drm_mode_getcrtc, 0),
660 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETCRTC, drm_mode_setcrtc, DRM_MASTER),
661 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPLANE, drm_mode_getplane, 0),
662 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETPLANE, drm_mode_setplane, DRM_MASTER),
663 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_CURSOR, drm_mode_cursor_ioctl, DRM_MASTER),
664 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETGAMMA, drm_mode_gamma_get_ioctl, 0),
665 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETGAMMA, drm_mode_gamma_set_ioctl, DRM_MASTER),
666 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETENCODER, drm_mode_getencoder, 0),
667 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETCONNECTOR, drm_mode_getconnector, 0),
668 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_ATTACHMODE, drm_noop, DRM_MASTER),
669 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_DETACHMODE, drm_noop, DRM_MASTER),
670 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPROPERTY, drm_mode_getproperty_ioctl, 0),
671 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETPROPERTY, drm_connector_property_set_ioctl, DRM_MASTER),
672 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPROPBLOB, drm_mode_getblob_ioctl, 0),
673 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETFB, drm_mode_getfb, 0),
674 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETFB2, drm_mode_getfb2_ioctl, 0),
675 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_ADDFB, drm_mode_addfb_ioctl, 0),
676 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_ADDFB2, drm_mode_addfb2_ioctl, 0),
677 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_RMFB, drm_mode_rmfb_ioctl, 0),
678 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_PAGE_FLIP, drm_mode_page_flip_ioctl, DRM_MASTER),
679 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_DIRTYFB, drm_mode_dirtyfb_ioctl, DRM_MASTER),
680 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_CREATE_DUMB, drm_mode_create_dumb_ioctl, 0),
681 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_MAP_DUMB, drm_mode_mmap_dumb_ioctl, 0),
682 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_DESTROY_DUMB, drm_mode_destroy_dumb_ioctl, 0),
683 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_OBJ_GETPROPERTIES, drm_mode_obj_get_properties_ioctl, 0),
684 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_OBJ_SETPROPERTY, drm_mode_obj_set_property_ioctl, DRM_MASTER),
685 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_CURSOR2, drm_mode_cursor2_ioctl, DRM_MASTER),
686 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_ATOMIC, drm_mode_atomic_ioctl, DRM_MASTER),
687 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_CREATEPROPBLOB, drm_mode_createblob_ioctl, 0),
688 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_DESTROYPROPBLOB, drm_mode_destroyblob_ioctl, 0),
689 
690 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_CREATE, drm_syncobj_create_ioctl,
691 		      DRM_RENDER_ALLOW),
692 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_DESTROY, drm_syncobj_destroy_ioctl,
693 		      DRM_RENDER_ALLOW),
694 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_HANDLE_TO_FD, drm_syncobj_handle_to_fd_ioctl,
695 		      DRM_RENDER_ALLOW),
696 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_FD_TO_HANDLE, drm_syncobj_fd_to_handle_ioctl,
697 		      DRM_RENDER_ALLOW),
698 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_TRANSFER, drm_syncobj_transfer_ioctl,
699 		      DRM_RENDER_ALLOW),
700 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_WAIT, drm_syncobj_wait_ioctl,
701 		      DRM_RENDER_ALLOW),
702 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_TIMELINE_WAIT, drm_syncobj_timeline_wait_ioctl,
703 		      DRM_RENDER_ALLOW),
704 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_RESET, drm_syncobj_reset_ioctl,
705 		      DRM_RENDER_ALLOW),
706 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_SIGNAL, drm_syncobj_signal_ioctl,
707 		      DRM_RENDER_ALLOW),
708 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_TIMELINE_SIGNAL, drm_syncobj_timeline_signal_ioctl,
709 		      DRM_RENDER_ALLOW),
710 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_QUERY, drm_syncobj_query_ioctl,
711 		      DRM_RENDER_ALLOW),
712 	DRM_IOCTL_DEF(DRM_IOCTL_CRTC_GET_SEQUENCE, drm_crtc_get_sequence_ioctl, 0),
713 	DRM_IOCTL_DEF(DRM_IOCTL_CRTC_QUEUE_SEQUENCE, drm_crtc_queue_sequence_ioctl, 0),
714 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_CREATE_LEASE, drm_mode_create_lease_ioctl, DRM_MASTER),
715 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_LIST_LESSEES, drm_mode_list_lessees_ioctl, DRM_MASTER),
716 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GET_LEASE, drm_mode_get_lease_ioctl, DRM_MASTER),
717 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_REVOKE_LEASE, drm_mode_revoke_lease_ioctl, DRM_MASTER),
718 };
719 
720 #define DRM_CORE_IOCTL_COUNT	ARRAY_SIZE( drm_ioctls )
721 
722 /**
723  * DOC: driver specific ioctls
724  *
725  * First things first, driver private IOCTLs should only be needed for drivers
726  * supporting rendering. Kernel modesetting is all standardized, and extended
727  * through properties. There are a few exceptions in some existing drivers,
728  * which define IOCTL for use by the display DRM master, but they all predate
729  * properties.
730  *
731  * Now if you do have a render driver you always have to support it through
732  * driver private properties. There's a few steps needed to wire all the things
733  * up.
734  *
735  * First you need to define the structure for your IOCTL in your driver private
736  * UAPI header in ``include/uapi/drm/my_driver_drm.h``::
737  *
738  *     struct my_driver_operation {
739  *             u32 some_thing;
740  *             u32 another_thing;
741  *     };
742  *
743  * Please make sure that you follow all the best practices from
744  * ``Documentation/process/botching-up-ioctls.rst``. Note that drm_ioctl()
745  * automatically zero-extends structures, hence make sure you can add more stuff
746  * at the end, i.e. don't put a variable sized array there.
747  *
748  * Then you need to define your IOCTL number, using one of DRM_IO(), DRM_IOR(),
749  * DRM_IOW() or DRM_IOWR(). It must start with the DRM_IOCTL\_ prefix::
750  *
751  *     ##define DRM_IOCTL_MY_DRIVER_OPERATION \
752  *         DRM_IOW(DRM_COMMAND_BASE, struct my_driver_operation)
753  *
754  * DRM driver private IOCTL must be in the range from DRM_COMMAND_BASE to
755  * DRM_COMMAND_END. Finally you need an array of &struct drm_ioctl_desc to wire
756  * up the handlers and set the access rights::
757  *
758  *     static const struct drm_ioctl_desc my_driver_ioctls[] = {
759  *         DRM_IOCTL_DEF_DRV(MY_DRIVER_OPERATION, my_driver_operation,
760  *                 DRM_AUTH|DRM_RENDER_ALLOW),
761  *     };
762  *
763  * And then assign this to the &drm_driver.ioctls field in your driver
764  * structure.
765  *
766  * See the separate chapter on :ref:`file operations<drm_driver_fops>` for how
767  * the driver-specific IOCTLs are wired up.
768  */
769 
drm_ioctl_kernel(struct file * file,drm_ioctl_t * func,void * kdata,u32 flags)770 long drm_ioctl_kernel(struct file *file, drm_ioctl_t *func, void *kdata,
771 		      u32 flags)
772 {
773 	struct drm_file *file_priv = file->private_data;
774 	struct drm_device *dev = file_priv->minor->dev;
775 	int retcode;
776 
777 	if (drm_dev_is_unplugged(dev))
778 		return -ENODEV;
779 
780 	retcode = drm_ioctl_permit(flags, file_priv);
781 	if (unlikely(retcode))
782 		return retcode;
783 
784 	/* Enforce sane locking for modern driver ioctls. */
785 	if (likely(!drm_core_check_feature(dev, DRIVER_LEGACY)) ||
786 	    (flags & DRM_UNLOCKED))
787 		retcode = func(dev, kdata, file_priv);
788 	else {
789 		mutex_lock(&drm_global_mutex);
790 		retcode = func(dev, kdata, file_priv);
791 		mutex_unlock(&drm_global_mutex);
792 	}
793 	return retcode;
794 }
795 EXPORT_SYMBOL(drm_ioctl_kernel);
796 
797 /**
798  * drm_ioctl - ioctl callback implementation for DRM drivers
799  * @filp: file this ioctl is called on
800  * @cmd: ioctl cmd number
801  * @arg: user argument
802  *
803  * Looks up the ioctl function in the DRM core and the driver dispatch table,
804  * stored in &drm_driver.ioctls. It checks for necessary permission by calling
805  * drm_ioctl_permit(), and dispatches to the respective function.
806  *
807  * Returns:
808  * Zero on success, negative error code on failure.
809  */
drm_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)810 long drm_ioctl(struct file *filp,
811 	      unsigned int cmd, unsigned long arg)
812 {
813 	struct drm_file *file_priv = filp->private_data;
814 	struct drm_device *dev;
815 	const struct drm_ioctl_desc *ioctl = NULL;
816 	drm_ioctl_t *func;
817 	unsigned int nr = DRM_IOCTL_NR(cmd);
818 	int retcode = -EINVAL;
819 	char stack_kdata[128];
820 	char *kdata = NULL;
821 	unsigned int in_size, out_size, drv_size, ksize;
822 	bool is_driver_ioctl;
823 
824 	dev = file_priv->minor->dev;
825 
826 	if (drm_dev_is_unplugged(dev))
827 		return -ENODEV;
828 
829 	is_driver_ioctl = nr >= DRM_COMMAND_BASE && nr < DRM_COMMAND_END;
830 
831 	if (is_driver_ioctl) {
832 		/* driver ioctl */
833 		unsigned int index = nr - DRM_COMMAND_BASE;
834 
835 		if (index >= dev->driver->num_ioctls)
836 			goto err_i1;
837 		index = array_index_nospec(index, dev->driver->num_ioctls);
838 		ioctl = &dev->driver->ioctls[index];
839 	} else {
840 		/* core ioctl */
841 		if (nr >= DRM_CORE_IOCTL_COUNT)
842 			goto err_i1;
843 		nr = array_index_nospec(nr, DRM_CORE_IOCTL_COUNT);
844 		ioctl = &drm_ioctls[nr];
845 	}
846 
847 	drv_size = _IOC_SIZE(ioctl->cmd);
848 	out_size = in_size = _IOC_SIZE(cmd);
849 	if ((cmd & ioctl->cmd & IOC_IN) == 0)
850 		in_size = 0;
851 	if ((cmd & ioctl->cmd & IOC_OUT) == 0)
852 		out_size = 0;
853 	ksize = max(max(in_size, out_size), drv_size);
854 
855 	DRM_DEBUG("comm=\"%s\" pid=%d, dev=0x%lx, auth=%d, %s\n",
856 		  current->comm, task_pid_nr(current),
857 		  (long)old_encode_dev(file_priv->minor->kdev->devt),
858 		  file_priv->authenticated, ioctl->name);
859 
860 	/* Do not trust userspace, use our own definition */
861 	func = ioctl->func;
862 
863 	if (unlikely(!func)) {
864 		DRM_DEBUG("no function\n");
865 		retcode = -EINVAL;
866 		goto err_i1;
867 	}
868 
869 	if (ksize <= sizeof(stack_kdata)) {
870 		kdata = stack_kdata;
871 	} else {
872 		kdata = kmalloc(ksize, GFP_KERNEL);
873 		if (!kdata) {
874 			retcode = -ENOMEM;
875 			goto err_i1;
876 		}
877 	}
878 
879 	if (copy_from_user(kdata, (void __user *)arg, in_size) != 0) {
880 		retcode = -EFAULT;
881 		goto err_i1;
882 	}
883 
884 	if (ksize > in_size)
885 		memset(kdata + in_size, 0, ksize - in_size);
886 
887 	retcode = drm_ioctl_kernel(filp, func, kdata, ioctl->flags);
888 	if (copy_to_user((void __user *)arg, kdata, out_size) != 0)
889 		retcode = -EFAULT;
890 
891       err_i1:
892 	if (!ioctl)
893 		DRM_DEBUG("invalid ioctl: comm=\"%s\", pid=%d, dev=0x%lx, auth=%d, cmd=0x%02x, nr=0x%02x\n",
894 			  current->comm, task_pid_nr(current),
895 			  (long)old_encode_dev(file_priv->minor->kdev->devt),
896 			  file_priv->authenticated, cmd, nr);
897 
898 	if (kdata != stack_kdata)
899 		kfree(kdata);
900 	if (retcode)
901 		DRM_DEBUG("comm=\"%s\", pid=%d, ret=%d\n", current->comm,
902 			  task_pid_nr(current), retcode);
903 	return retcode;
904 }
905 EXPORT_SYMBOL(drm_ioctl);
906 
907 /**
908  * drm_ioctl_flags - Check for core ioctl and return ioctl permission flags
909  * @nr: ioctl number
910  * @flags: where to return the ioctl permission flags
911  *
912  * This ioctl is only used by the vmwgfx driver to augment the access checks
913  * done by the drm core and insofar a pretty decent layering violation. This
914  * shouldn't be used by any drivers.
915  *
916  * Returns:
917  * True if the @nr corresponds to a DRM core ioctl number, false otherwise.
918  */
drm_ioctl_flags(unsigned int nr,unsigned int * flags)919 bool drm_ioctl_flags(unsigned int nr, unsigned int *flags)
920 {
921 	if (nr >= DRM_COMMAND_BASE && nr < DRM_COMMAND_END)
922 		return false;
923 
924 	if (nr >= DRM_CORE_IOCTL_COUNT)
925 		return false;
926 	nr = array_index_nospec(nr, DRM_CORE_IOCTL_COUNT);
927 
928 	*flags = drm_ioctls[nr].flags;
929 	return true;
930 }
931 EXPORT_SYMBOL(drm_ioctl_flags);
932