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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;
122 
123 	mutex_lock(&dev->master_mutex);
124 	master = file_priv->master;
125 	if (u->unique_len >= master->unique_len) {
126 		if (copy_to_user(u->unique, master->unique, master->unique_len)) {
127 			mutex_unlock(&dev->master_mutex);
128 			return -EFAULT;
129 		}
130 	}
131 	u->unique_len = master->unique_len;
132 	mutex_unlock(&dev->master_mutex);
133 
134 	return 0;
135 }
136 
137 static void
drm_unset_busid(struct drm_device * dev,struct drm_master * master)138 drm_unset_busid(struct drm_device *dev,
139 		struct drm_master *master)
140 {
141 	kfree(master->unique);
142 	master->unique = NULL;
143 	master->unique_len = 0;
144 }
145 
drm_set_busid(struct drm_device * dev,struct drm_file * file_priv)146 static int drm_set_busid(struct drm_device *dev, struct drm_file *file_priv)
147 {
148 	struct drm_master *master = file_priv->master;
149 	int ret;
150 
151 	if (master->unique != NULL)
152 		drm_unset_busid(dev, master);
153 
154 	if (dev->dev && dev_is_pci(dev->dev)) {
155 		ret = drm_pci_set_busid(dev, master);
156 		if (ret) {
157 			drm_unset_busid(dev, master);
158 			return ret;
159 		}
160 	} else {
161 		WARN_ON(!dev->unique);
162 		master->unique = kstrdup(dev->unique, GFP_KERNEL);
163 		if (master->unique)
164 			master->unique_len = strlen(dev->unique);
165 	}
166 
167 	return 0;
168 }
169 
170 /*
171  * Get client information.
172  *
173  * \param inode device inode.
174  * \param file_priv DRM file private.
175  * \param cmd command.
176  * \param arg user argument, pointing to a drm_client structure.
177  *
178  * \return zero on success or a negative number on failure.
179  *
180  * Searches for the client with the specified index and copies its information
181  * into userspace
182  */
drm_getclient(struct drm_device * dev,void * data,struct drm_file * file_priv)183 int drm_getclient(struct drm_device *dev, void *data,
184 		  struct drm_file *file_priv)
185 {
186 	struct drm_client *client = data;
187 
188 	/*
189 	 * Hollowed-out getclient ioctl to keep some dead old drm tests/tools
190 	 * not breaking completely. Userspace tools stop enumerating one they
191 	 * get -EINVAL, hence this is the return value we need to hand back for
192 	 * no clients tracked.
193 	 *
194 	 * Unfortunately some clients (*cough* libva *cough*) use this in a fun
195 	 * attempt to figure out whether they're authenticated or not. Since
196 	 * that's the only thing they care about, give it to the directly
197 	 * instead of walking one giant list.
198 	 */
199 	if (client->idx == 0) {
200 		client->auth = file_priv->authenticated;
201 		client->pid = task_pid_vnr(current);
202 		client->uid = overflowuid;
203 		client->magic = 0;
204 		client->iocs = 0;
205 
206 		return 0;
207 	} else {
208 		return -EINVAL;
209 	}
210 }
211 
212 /*
213  * Get statistics information.
214  *
215  * \param inode device inode.
216  * \param file_priv DRM file private.
217  * \param cmd command.
218  * \param arg user argument, pointing to a drm_stats structure.
219  *
220  * \return zero on success or a negative number on failure.
221  */
drm_getstats(struct drm_device * dev,void * data,struct drm_file * file_priv)222 static int drm_getstats(struct drm_device *dev, void *data,
223 		 struct drm_file *file_priv)
224 {
225 	struct drm_stats *stats = data;
226 
227 	/* Clear stats to prevent userspace from eating its stack garbage. */
228 	memset(stats, 0, sizeof(*stats));
229 
230 	return 0;
231 }
232 
233 /*
234  * Get device/driver capabilities
235  */
drm_getcap(struct drm_device * dev,void * data,struct drm_file * file_priv)236 static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_priv)
237 {
238 	struct drm_get_cap *req = data;
239 	struct drm_crtc *crtc;
240 
241 	req->value = 0;
242 
243 	/* Only some caps make sense with UMS/render-only drivers. */
244 	switch (req->capability) {
245 	case DRM_CAP_TIMESTAMP_MONOTONIC:
246 		req->value = 1;
247 		return 0;
248 	case DRM_CAP_PRIME:
249 		req->value |= dev->driver->prime_fd_to_handle ? DRM_PRIME_CAP_IMPORT : 0;
250 		req->value |= dev->driver->prime_handle_to_fd ? DRM_PRIME_CAP_EXPORT : 0;
251 		return 0;
252 	case DRM_CAP_SYNCOBJ:
253 		req->value = drm_core_check_feature(dev, DRIVER_SYNCOBJ);
254 		return 0;
255 	case DRM_CAP_SYNCOBJ_TIMELINE:
256 		req->value = drm_core_check_feature(dev, DRIVER_SYNCOBJ_TIMELINE);
257 		return 0;
258 	}
259 
260 	/* Other caps only work with KMS drivers */
261 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
262 		return -EOPNOTSUPP;
263 
264 	switch (req->capability) {
265 	case DRM_CAP_DUMB_BUFFER:
266 		if (dev->driver->dumb_create)
267 			req->value = 1;
268 		break;
269 	case DRM_CAP_VBLANK_HIGH_CRTC:
270 		req->value = 1;
271 		break;
272 	case DRM_CAP_DUMB_PREFERRED_DEPTH:
273 		req->value = dev->mode_config.preferred_depth;
274 		break;
275 	case DRM_CAP_DUMB_PREFER_SHADOW:
276 		req->value = dev->mode_config.prefer_shadow;
277 		break;
278 	case DRM_CAP_ASYNC_PAGE_FLIP:
279 		req->value = dev->mode_config.async_page_flip;
280 		break;
281 	case DRM_CAP_PAGE_FLIP_TARGET:
282 		req->value = 1;
283 		drm_for_each_crtc(crtc, dev) {
284 			if (!crtc->funcs->page_flip_target)
285 				req->value = 0;
286 		}
287 		break;
288 	case DRM_CAP_CURSOR_WIDTH:
289 		if (dev->mode_config.cursor_width)
290 			req->value = dev->mode_config.cursor_width;
291 		else
292 			req->value = 64;
293 		break;
294 	case DRM_CAP_CURSOR_HEIGHT:
295 		if (dev->mode_config.cursor_height)
296 			req->value = dev->mode_config.cursor_height;
297 		else
298 			req->value = 64;
299 		break;
300 	case DRM_CAP_ADDFB2_MODIFIERS:
301 		req->value = dev->mode_config.allow_fb_modifiers;
302 		break;
303 	case DRM_CAP_CRTC_IN_VBLANK_EVENT:
304 		req->value = 1;
305 		break;
306 	default:
307 		return -EINVAL;
308 	}
309 	return 0;
310 }
311 
312 /*
313  * Set device/driver capabilities
314  */
315 static int
drm_setclientcap(struct drm_device * dev,void * data,struct drm_file * file_priv)316 drm_setclientcap(struct drm_device *dev, void *data, struct drm_file *file_priv)
317 {
318 	struct drm_set_client_cap *req = data;
319 
320 	/* No render-only settable capabilities for now */
321 
322 	/* Below caps that only works with KMS drivers */
323 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
324 		return -EOPNOTSUPP;
325 
326 	switch (req->capability) {
327 	case DRM_CLIENT_CAP_STEREO_3D:
328 		if (req->value > 1)
329 			return -EINVAL;
330 		file_priv->stereo_allowed = req->value;
331 		break;
332 	case DRM_CLIENT_CAP_UNIVERSAL_PLANES:
333 		if (req->value > 1)
334 			return -EINVAL;
335 		file_priv->universal_planes = req->value;
336 		break;
337 	case DRM_CLIENT_CAP_ATOMIC:
338 		if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
339 			return -EOPNOTSUPP;
340 		/* The modesetting DDX has a totally broken idea of atomic. */
341 		if (current->comm[0] == 'X' && req->value == 1) {
342 			pr_info("broken atomic modeset userspace detected, disabling atomic\n");
343 			return -EOPNOTSUPP;
344 		}
345 		if (req->value > 2)
346 			return -EINVAL;
347 		file_priv->atomic = req->value;
348 		file_priv->universal_planes = req->value;
349 		/*
350 		 * No atomic user-space blows up on aspect ratio mode bits.
351 		 */
352 		file_priv->aspect_ratio_allowed = req->value;
353 		break;
354 	case DRM_CLIENT_CAP_ASPECT_RATIO:
355 		if (req->value > 1)
356 			return -EINVAL;
357 		file_priv->aspect_ratio_allowed = req->value;
358 		break;
359 	case DRM_CLIENT_CAP_WRITEBACK_CONNECTORS:
360 		if (!file_priv->atomic)
361 			return -EINVAL;
362 		if (req->value > 1)
363 			return -EINVAL;
364 		file_priv->writeback_connectors = req->value;
365 		break;
366 	default:
367 		return -EINVAL;
368 	}
369 
370 	return 0;
371 }
372 
373 /*
374  * Setversion ioctl.
375  *
376  * \param inode device inode.
377  * \param file_priv DRM file private.
378  * \param cmd command.
379  * \param arg user argument, pointing to a drm_lock structure.
380  * \return zero on success or negative number on failure.
381  *
382  * Sets the requested interface version
383  */
drm_setversion(struct drm_device * dev,void * data,struct drm_file * file_priv)384 static int drm_setversion(struct drm_device *dev, void *data, struct drm_file *file_priv)
385 {
386 	struct drm_set_version *sv = data;
387 	int if_version, retcode = 0;
388 
389 	mutex_lock(&dev->master_mutex);
390 	if (sv->drm_di_major != -1) {
391 		if (sv->drm_di_major != DRM_IF_MAJOR ||
392 		    sv->drm_di_minor < 0 || sv->drm_di_minor > DRM_IF_MINOR) {
393 			retcode = -EINVAL;
394 			goto done;
395 		}
396 		if_version = DRM_IF_VERSION(sv->drm_di_major,
397 					    sv->drm_di_minor);
398 		dev->if_version = max(if_version, dev->if_version);
399 		if (sv->drm_di_minor >= 1) {
400 			/*
401 			 * Version 1.1 includes tying of DRM to specific device
402 			 * Version 1.4 has proper PCI domain support
403 			 */
404 			retcode = drm_set_busid(dev, file_priv);
405 			if (retcode)
406 				goto done;
407 		}
408 	}
409 
410 	if (sv->drm_dd_major != -1) {
411 		if (sv->drm_dd_major != dev->driver->major ||
412 		    sv->drm_dd_minor < 0 || sv->drm_dd_minor >
413 		    dev->driver->minor) {
414 			retcode = -EINVAL;
415 			goto done;
416 		}
417 	}
418 
419 done:
420 	sv->drm_di_major = DRM_IF_MAJOR;
421 	sv->drm_di_minor = DRM_IF_MINOR;
422 	sv->drm_dd_major = dev->driver->major;
423 	sv->drm_dd_minor = dev->driver->minor;
424 	mutex_unlock(&dev->master_mutex);
425 
426 	return retcode;
427 }
428 
429 /**
430  * drm_noop - DRM no-op ioctl implemntation
431  * @dev: DRM device for the ioctl
432  * @data: data pointer for the ioctl
433  * @file_priv: DRM file for the ioctl call
434  *
435  * This no-op implementation for drm ioctls is useful for deprecated
436  * functionality where we can't return a failure code because existing userspace
437  * checks the result of the ioctl, but doesn't care about the action.
438  *
439  * Always returns successfully with 0.
440  */
drm_noop(struct drm_device * dev,void * data,struct drm_file * file_priv)441 int drm_noop(struct drm_device *dev, void *data,
442 	     struct drm_file *file_priv)
443 {
444 	DRM_DEBUG("\n");
445 	return 0;
446 }
447 EXPORT_SYMBOL(drm_noop);
448 
449 /**
450  * drm_invalid_op - DRM invalid ioctl implemntation
451  * @dev: DRM device for the ioctl
452  * @data: data pointer for the ioctl
453  * @file_priv: DRM file for the ioctl call
454  *
455  * This no-op implementation for drm ioctls is useful for deprecated
456  * functionality where we really don't want to allow userspace to call the ioctl
457  * any more. This is the case for old ums interfaces for drivers that
458  * transitioned to kms gradually and so kept the old legacy tables around. This
459  * only applies to radeon and i915 kms drivers, other drivers shouldn't need to
460  * use this function.
461  *
462  * Always fails with a return value of -EINVAL.
463  */
drm_invalid_op(struct drm_device * dev,void * data,struct drm_file * file_priv)464 int drm_invalid_op(struct drm_device *dev, void *data,
465 		   struct drm_file *file_priv)
466 {
467 	return -EINVAL;
468 }
469 EXPORT_SYMBOL(drm_invalid_op);
470 
471 /*
472  * Copy and IOCTL return string to user space
473  */
drm_copy_field(char __user * buf,size_t * buf_len,const char * value)474 static int drm_copy_field(char __user *buf, size_t *buf_len, const char *value)
475 {
476 	int len;
477 
478 	/* don't overflow userbuf */
479 	len = strlen(value);
480 	if (len > *buf_len)
481 		len = *buf_len;
482 
483 	/* let userspace know exact length of driver value (which could be
484 	 * larger than the userspace-supplied buffer) */
485 	*buf_len = strlen(value);
486 
487 	/* finally, try filling in the userbuf */
488 	if (len && buf)
489 		if (copy_to_user(buf, value, len))
490 			return -EFAULT;
491 	return 0;
492 }
493 
494 /*
495  * Get version information
496  *
497  * \param inode device inode.
498  * \param filp file pointer.
499  * \param cmd command.
500  * \param arg user argument, pointing to a drm_version structure.
501  * \return zero on success or negative number on failure.
502  *
503  * Fills in the version information in \p arg.
504  */
drm_version(struct drm_device * dev,void * data,struct drm_file * file_priv)505 int drm_version(struct drm_device *dev, void *data,
506 		       struct drm_file *file_priv)
507 {
508 	struct drm_version *version = data;
509 	int err;
510 
511 	version->version_major = dev->driver->major;
512 	version->version_minor = dev->driver->minor;
513 	version->version_patchlevel = dev->driver->patchlevel;
514 	err = drm_copy_field(version->name, &version->name_len,
515 			dev->driver->name);
516 	if (!err)
517 		err = drm_copy_field(version->date, &version->date_len,
518 				dev->driver->date);
519 	if (!err)
520 		err = drm_copy_field(version->desc, &version->desc_len,
521 				dev->driver->desc);
522 
523 	return err;
524 }
525 
526 /**
527  * drm_ioctl_permit - Check ioctl permissions against caller
528  *
529  * @flags: ioctl permission flags.
530  * @file_priv: Pointer to struct drm_file identifying the caller.
531  *
532  * Checks whether the caller is allowed to run an ioctl with the
533  * indicated permissions.
534  *
535  * Returns:
536  * Zero if allowed, -EACCES otherwise.
537  */
drm_ioctl_permit(u32 flags,struct drm_file * file_priv)538 int drm_ioctl_permit(u32 flags, struct drm_file *file_priv)
539 {
540 	/* ROOT_ONLY is only for CAP_SYS_ADMIN */
541 	if (unlikely((flags & DRM_ROOT_ONLY) && !capable(CAP_SYS_ADMIN)))
542 		return -EACCES;
543 
544 	/* AUTH is only for authenticated or render client */
545 	if (unlikely((flags & DRM_AUTH) && !drm_is_render_client(file_priv) &&
546 		     !file_priv->authenticated))
547 		return -EACCES;
548 
549 	/* MASTER is only for master or control clients */
550 	if (unlikely((flags & DRM_MASTER) &&
551 		     !drm_is_current_master(file_priv)))
552 		return -EACCES;
553 
554 	/* Render clients must be explicitly allowed */
555 	if (unlikely(!(flags & DRM_RENDER_ALLOW) &&
556 		     drm_is_render_client(file_priv)))
557 		return -EACCES;
558 
559 	return 0;
560 }
561 EXPORT_SYMBOL(drm_ioctl_permit);
562 
563 #define DRM_IOCTL_DEF(ioctl, _func, _flags)	\
564 	[DRM_IOCTL_NR(ioctl)] = {		\
565 		.cmd = ioctl,			\
566 		.func = _func,			\
567 		.flags = _flags,		\
568 		.name = #ioctl			\
569 	}
570 
571 #if IS_ENABLED(CONFIG_DRM_LEGACY)
572 #define DRM_LEGACY_IOCTL_DEF(ioctl, _func, _flags)  DRM_IOCTL_DEF(ioctl, _func, _flags)
573 #else
574 #define DRM_LEGACY_IOCTL_DEF(ioctl, _func, _flags) DRM_IOCTL_DEF(ioctl, drm_invalid_op, _flags)
575 #endif
576 
577 /* Ioctl table */
578 static const struct drm_ioctl_desc drm_ioctls[] = {
579 	DRM_IOCTL_DEF(DRM_IOCTL_VERSION, drm_version, DRM_RENDER_ALLOW),
580 	DRM_IOCTL_DEF(DRM_IOCTL_GET_UNIQUE, drm_getunique, 0),
581 	DRM_IOCTL_DEF(DRM_IOCTL_GET_MAGIC, drm_getmagic, 0),
582 	DRM_IOCTL_DEF(DRM_IOCTL_IRQ_BUSID, drm_irq_by_busid, DRM_MASTER|DRM_ROOT_ONLY),
583 
584 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_GET_MAP, drm_legacy_getmap_ioctl, 0),
585 
586 	DRM_IOCTL_DEF(DRM_IOCTL_GET_CLIENT, drm_getclient, 0),
587 	DRM_IOCTL_DEF(DRM_IOCTL_GET_STATS, drm_getstats, 0),
588 	DRM_IOCTL_DEF(DRM_IOCTL_GET_CAP, drm_getcap, DRM_RENDER_ALLOW),
589 	DRM_IOCTL_DEF(DRM_IOCTL_SET_CLIENT_CAP, drm_setclientcap, 0),
590 	DRM_IOCTL_DEF(DRM_IOCTL_SET_VERSION, drm_setversion, DRM_MASTER),
591 
592 	DRM_IOCTL_DEF(DRM_IOCTL_SET_UNIQUE, drm_invalid_op, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
593 	DRM_IOCTL_DEF(DRM_IOCTL_BLOCK, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
594 	DRM_IOCTL_DEF(DRM_IOCTL_UNBLOCK, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
595 	DRM_IOCTL_DEF(DRM_IOCTL_AUTH_MAGIC, drm_authmagic, DRM_MASTER),
596 
597 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_ADD_MAP, drm_legacy_addmap_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
598 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_RM_MAP, drm_legacy_rmmap_ioctl, DRM_AUTH),
599 
600 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_SET_SAREA_CTX, drm_legacy_setsareactx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
601 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_GET_SAREA_CTX, drm_legacy_getsareactx, DRM_AUTH),
602 
603 	DRM_IOCTL_DEF(DRM_IOCTL_SET_MASTER, drm_setmaster_ioctl, 0),
604 	DRM_IOCTL_DEF(DRM_IOCTL_DROP_MASTER, drm_dropmaster_ioctl, 0),
605 
606 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_ADD_CTX, drm_legacy_addctx, DRM_AUTH|DRM_ROOT_ONLY),
607 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_RM_CTX, drm_legacy_rmctx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
608 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_MOD_CTX, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
609 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_GET_CTX, drm_legacy_getctx, DRM_AUTH),
610 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_SWITCH_CTX, drm_legacy_switchctx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
611 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_NEW_CTX, drm_legacy_newctx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
612 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_RES_CTX, drm_legacy_resctx, DRM_AUTH),
613 
614 	DRM_IOCTL_DEF(DRM_IOCTL_ADD_DRAW, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
615 	DRM_IOCTL_DEF(DRM_IOCTL_RM_DRAW, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
616 
617 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_LOCK, drm_legacy_lock, DRM_AUTH),
618 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_UNLOCK, drm_legacy_unlock, DRM_AUTH),
619 
620 	DRM_IOCTL_DEF(DRM_IOCTL_FINISH, drm_noop, DRM_AUTH),
621 
622 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_ADD_BUFS, drm_legacy_addbufs, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
623 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_MARK_BUFS, drm_legacy_markbufs, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
624 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_INFO_BUFS, drm_legacy_infobufs, DRM_AUTH),
625 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_MAP_BUFS, drm_legacy_mapbufs, DRM_AUTH),
626 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_FREE_BUFS, drm_legacy_freebufs, DRM_AUTH),
627 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_DMA, drm_legacy_dma_ioctl, DRM_AUTH),
628 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_CONTROL, drm_legacy_irq_control, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
629 
630 #if IS_ENABLED(CONFIG_AGP)
631 	DRM_IOCTL_DEF(DRM_IOCTL_AGP_ACQUIRE, drm_agp_acquire_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
632 	DRM_IOCTL_DEF(DRM_IOCTL_AGP_RELEASE, drm_agp_release_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
633 	DRM_IOCTL_DEF(DRM_IOCTL_AGP_ENABLE, drm_agp_enable_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
634 	DRM_IOCTL_DEF(DRM_IOCTL_AGP_INFO, drm_agp_info_ioctl, DRM_AUTH),
635 	DRM_IOCTL_DEF(DRM_IOCTL_AGP_ALLOC, drm_agp_alloc_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
636 	DRM_IOCTL_DEF(DRM_IOCTL_AGP_FREE, drm_agp_free_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
637 	DRM_IOCTL_DEF(DRM_IOCTL_AGP_BIND, drm_agp_bind_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
638 	DRM_IOCTL_DEF(DRM_IOCTL_AGP_UNBIND, drm_agp_unbind_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
639 #endif
640 
641 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_SG_ALLOC, drm_legacy_sg_alloc, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
642 	DRM_LEGACY_IOCTL_DEF(DRM_IOCTL_SG_FREE, drm_legacy_sg_free, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
643 
644 	DRM_IOCTL_DEF(DRM_IOCTL_WAIT_VBLANK, drm_wait_vblank_ioctl, DRM_UNLOCKED),
645 
646 	DRM_IOCTL_DEF(DRM_IOCTL_MODESET_CTL, drm_legacy_modeset_ctl_ioctl, 0),
647 
648 	DRM_IOCTL_DEF(DRM_IOCTL_UPDATE_DRAW, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
649 
650 	DRM_IOCTL_DEF(DRM_IOCTL_GEM_CLOSE, drm_gem_close_ioctl, DRM_RENDER_ALLOW),
651 	DRM_IOCTL_DEF(DRM_IOCTL_GEM_FLINK, drm_gem_flink_ioctl, DRM_AUTH),
652 	DRM_IOCTL_DEF(DRM_IOCTL_GEM_OPEN, drm_gem_open_ioctl, DRM_AUTH),
653 
654 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETRESOURCES, drm_mode_getresources, 0),
655 
656 	DRM_IOCTL_DEF(DRM_IOCTL_PRIME_HANDLE_TO_FD, drm_prime_handle_to_fd_ioctl, DRM_RENDER_ALLOW),
657 	DRM_IOCTL_DEF(DRM_IOCTL_PRIME_FD_TO_HANDLE, drm_prime_fd_to_handle_ioctl, DRM_RENDER_ALLOW),
658 
659 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPLANERESOURCES, drm_mode_getplane_res, 0),
660 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETCRTC, drm_mode_getcrtc, 0),
661 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETCRTC, drm_mode_setcrtc, DRM_MASTER),
662 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPLANE, drm_mode_getplane, 0),
663 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETPLANE, drm_mode_setplane, DRM_MASTER),
664 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_CURSOR, drm_mode_cursor_ioctl, DRM_MASTER),
665 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETGAMMA, drm_mode_gamma_get_ioctl, 0),
666 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETGAMMA, drm_mode_gamma_set_ioctl, DRM_MASTER),
667 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETENCODER, drm_mode_getencoder, 0),
668 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETCONNECTOR, drm_mode_getconnector, 0),
669 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_ATTACHMODE, drm_noop, DRM_MASTER),
670 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_DETACHMODE, drm_noop, DRM_MASTER),
671 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPROPERTY, drm_mode_getproperty_ioctl, 0),
672 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETPROPERTY, drm_connector_property_set_ioctl, DRM_MASTER),
673 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPROPBLOB, drm_mode_getblob_ioctl, 0),
674 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETFB, drm_mode_getfb, 0),
675 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETFB2, drm_mode_getfb2_ioctl, 0),
676 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_ADDFB, drm_mode_addfb_ioctl, 0),
677 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_ADDFB2, drm_mode_addfb2_ioctl, 0),
678 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_RMFB, drm_mode_rmfb_ioctl, 0),
679 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_PAGE_FLIP, drm_mode_page_flip_ioctl, DRM_MASTER),
680 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_DIRTYFB, drm_mode_dirtyfb_ioctl, DRM_MASTER),
681 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_CREATE_DUMB, drm_mode_create_dumb_ioctl, 0),
682 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_MAP_DUMB, drm_mode_mmap_dumb_ioctl, 0),
683 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_DESTROY_DUMB, drm_mode_destroy_dumb_ioctl, 0),
684 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_OBJ_GETPROPERTIES, drm_mode_obj_get_properties_ioctl, 0),
685 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_OBJ_SETPROPERTY, drm_mode_obj_set_property_ioctl, DRM_MASTER),
686 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_CURSOR2, drm_mode_cursor2_ioctl, DRM_MASTER),
687 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_ATOMIC, drm_mode_atomic_ioctl, DRM_MASTER),
688 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_CREATEPROPBLOB, drm_mode_createblob_ioctl, 0),
689 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_DESTROYPROPBLOB, drm_mode_destroyblob_ioctl, 0),
690 
691 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_CREATE, drm_syncobj_create_ioctl,
692 		      DRM_RENDER_ALLOW),
693 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_DESTROY, drm_syncobj_destroy_ioctl,
694 		      DRM_RENDER_ALLOW),
695 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_HANDLE_TO_FD, drm_syncobj_handle_to_fd_ioctl,
696 		      DRM_RENDER_ALLOW),
697 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_FD_TO_HANDLE, drm_syncobj_fd_to_handle_ioctl,
698 		      DRM_RENDER_ALLOW),
699 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_TRANSFER, drm_syncobj_transfer_ioctl,
700 		      DRM_RENDER_ALLOW),
701 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_WAIT, drm_syncobj_wait_ioctl,
702 		      DRM_RENDER_ALLOW),
703 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_TIMELINE_WAIT, drm_syncobj_timeline_wait_ioctl,
704 		      DRM_RENDER_ALLOW),
705 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_RESET, drm_syncobj_reset_ioctl,
706 		      DRM_RENDER_ALLOW),
707 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_SIGNAL, drm_syncobj_signal_ioctl,
708 		      DRM_RENDER_ALLOW),
709 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_TIMELINE_SIGNAL, drm_syncobj_timeline_signal_ioctl,
710 		      DRM_RENDER_ALLOW),
711 	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_QUERY, drm_syncobj_query_ioctl,
712 		      DRM_RENDER_ALLOW),
713 	DRM_IOCTL_DEF(DRM_IOCTL_CRTC_GET_SEQUENCE, drm_crtc_get_sequence_ioctl, 0),
714 	DRM_IOCTL_DEF(DRM_IOCTL_CRTC_QUEUE_SEQUENCE, drm_crtc_queue_sequence_ioctl, 0),
715 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_CREATE_LEASE, drm_mode_create_lease_ioctl, DRM_MASTER),
716 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_LIST_LESSEES, drm_mode_list_lessees_ioctl, DRM_MASTER),
717 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GET_LEASE, drm_mode_get_lease_ioctl, DRM_MASTER),
718 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_REVOKE_LEASE, drm_mode_revoke_lease_ioctl, DRM_MASTER),
719 };
720 
721 #define DRM_CORE_IOCTL_COUNT	ARRAY_SIZE( drm_ioctls )
722 
723 /**
724  * DOC: driver specific ioctls
725  *
726  * First things first, driver private IOCTLs should only be needed for drivers
727  * supporting rendering. Kernel modesetting is all standardized, and extended
728  * through properties. There are a few exceptions in some existing drivers,
729  * which define IOCTL for use by the display DRM master, but they all predate
730  * properties.
731  *
732  * Now if you do have a render driver you always have to support it through
733  * driver private properties. There's a few steps needed to wire all the things
734  * up.
735  *
736  * First you need to define the structure for your IOCTL in your driver private
737  * UAPI header in ``include/uapi/drm/my_driver_drm.h``::
738  *
739  *     struct my_driver_operation {
740  *             u32 some_thing;
741  *             u32 another_thing;
742  *     };
743  *
744  * Please make sure that you follow all the best practices from
745  * ``Documentation/process/botching-up-ioctls.rst``. Note that drm_ioctl()
746  * automatically zero-extends structures, hence make sure you can add more stuff
747  * at the end, i.e. don't put a variable sized array there.
748  *
749  * Then you need to define your IOCTL number, using one of DRM_IO(), DRM_IOR(),
750  * DRM_IOW() or DRM_IOWR(). It must start with the DRM_IOCTL\_ prefix::
751  *
752  *     ##define DRM_IOCTL_MY_DRIVER_OPERATION \
753  *         DRM_IOW(DRM_COMMAND_BASE, struct my_driver_operation)
754  *
755  * DRM driver private IOCTL must be in the range from DRM_COMMAND_BASE to
756  * DRM_COMMAND_END. Finally you need an array of &struct drm_ioctl_desc to wire
757  * up the handlers and set the access rights::
758  *
759  *     static const struct drm_ioctl_desc my_driver_ioctls[] = {
760  *         DRM_IOCTL_DEF_DRV(MY_DRIVER_OPERATION, my_driver_operation,
761  *                 DRM_AUTH|DRM_RENDER_ALLOW),
762  *     };
763  *
764  * And then assign this to the &drm_driver.ioctls field in your driver
765  * structure.
766  *
767  * See the separate chapter on :ref:`file operations<drm_driver_fops>` for how
768  * the driver-specific IOCTLs are wired up.
769  */
770 
drm_ioctl_kernel(struct file * file,drm_ioctl_t * func,void * kdata,u32 flags)771 long drm_ioctl_kernel(struct file *file, drm_ioctl_t *func, void *kdata,
772 		      u32 flags)
773 {
774 	struct drm_file *file_priv = file->private_data;
775 	struct drm_device *dev = file_priv->minor->dev;
776 	int retcode;
777 
778 	if (drm_dev_is_unplugged(dev))
779 		return -ENODEV;
780 
781 	retcode = drm_ioctl_permit(flags, file_priv);
782 	if (unlikely(retcode))
783 		return retcode;
784 
785 	/* Enforce sane locking for modern driver ioctls. */
786 	if (likely(!drm_core_check_feature(dev, DRIVER_LEGACY)) ||
787 	    (flags & DRM_UNLOCKED))
788 		retcode = func(dev, kdata, file_priv);
789 	else {
790 		mutex_lock(&drm_global_mutex);
791 		retcode = func(dev, kdata, file_priv);
792 		mutex_unlock(&drm_global_mutex);
793 	}
794 	return retcode;
795 }
796 EXPORT_SYMBOL(drm_ioctl_kernel);
797 
798 /**
799  * drm_ioctl - ioctl callback implementation for DRM drivers
800  * @filp: file this ioctl is called on
801  * @cmd: ioctl cmd number
802  * @arg: user argument
803  *
804  * Looks up the ioctl function in the DRM core and the driver dispatch table,
805  * stored in &drm_driver.ioctls. It checks for necessary permission by calling
806  * drm_ioctl_permit(), and dispatches to the respective function.
807  *
808  * Returns:
809  * Zero on success, negative error code on failure.
810  */
drm_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)811 long drm_ioctl(struct file *filp,
812 	      unsigned int cmd, unsigned long arg)
813 {
814 	struct drm_file *file_priv = filp->private_data;
815 	struct drm_device *dev;
816 	const struct drm_ioctl_desc *ioctl = NULL;
817 	drm_ioctl_t *func;
818 	unsigned int nr = DRM_IOCTL_NR(cmd);
819 	int retcode = -EINVAL;
820 	char stack_kdata[128];
821 	char *kdata = NULL;
822 	unsigned int in_size, out_size, drv_size, ksize;
823 	bool is_driver_ioctl;
824 
825 	dev = file_priv->minor->dev;
826 
827 	if (drm_dev_is_unplugged(dev))
828 		return -ENODEV;
829 
830        if (DRM_IOCTL_TYPE(cmd) != DRM_IOCTL_BASE)
831                return -ENOTTY;
832 
833 	is_driver_ioctl = nr >= DRM_COMMAND_BASE && nr < DRM_COMMAND_END;
834 
835 	if (is_driver_ioctl) {
836 		/* driver ioctl */
837 		unsigned int index = nr - DRM_COMMAND_BASE;
838 
839 		if (index >= dev->driver->num_ioctls)
840 			goto err_i1;
841 		index = array_index_nospec(index, dev->driver->num_ioctls);
842 		ioctl = &dev->driver->ioctls[index];
843 	} else {
844 		/* core ioctl */
845 		if (nr >= DRM_CORE_IOCTL_COUNT)
846 			goto err_i1;
847 		nr = array_index_nospec(nr, DRM_CORE_IOCTL_COUNT);
848 		ioctl = &drm_ioctls[nr];
849 	}
850 
851 	drv_size = _IOC_SIZE(ioctl->cmd);
852 	out_size = in_size = _IOC_SIZE(cmd);
853 	if ((cmd & ioctl->cmd & IOC_IN) == 0)
854 		in_size = 0;
855 	if ((cmd & ioctl->cmd & IOC_OUT) == 0)
856 		out_size = 0;
857 	ksize = max(max(in_size, out_size), drv_size);
858 
859 	DRM_DEBUG("comm=\"%s\" pid=%d, dev=0x%lx, auth=%d, %s\n",
860 		  current->comm, task_pid_nr(current),
861 		  (long)old_encode_dev(file_priv->minor->kdev->devt),
862 		  file_priv->authenticated, ioctl->name);
863 
864 	/* Do not trust userspace, use our own definition */
865 	func = ioctl->func;
866 
867 	if (unlikely(!func)) {
868 		DRM_DEBUG("no function\n");
869 		retcode = -EINVAL;
870 		goto err_i1;
871 	}
872 
873 	if (ksize <= sizeof(stack_kdata)) {
874 		kdata = stack_kdata;
875 	} else {
876 		kdata = kmalloc(ksize, GFP_KERNEL);
877 		if (!kdata) {
878 			retcode = -ENOMEM;
879 			goto err_i1;
880 		}
881 	}
882 
883 	if (copy_from_user(kdata, (void __user *)arg, in_size) != 0) {
884 		retcode = -EFAULT;
885 		goto err_i1;
886 	}
887 
888 	if (ksize > in_size)
889 		memset(kdata + in_size, 0, ksize - in_size);
890 
891 	retcode = drm_ioctl_kernel(filp, func, kdata, ioctl->flags);
892 	if (copy_to_user((void __user *)arg, kdata, out_size) != 0)
893 		retcode = -EFAULT;
894 
895       err_i1:
896 	if (!ioctl)
897 		DRM_DEBUG("invalid ioctl: comm=\"%s\", pid=%d, dev=0x%lx, auth=%d, cmd=0x%02x, nr=0x%02x\n",
898 			  current->comm, task_pid_nr(current),
899 			  (long)old_encode_dev(file_priv->minor->kdev->devt),
900 			  file_priv->authenticated, cmd, nr);
901 
902 	if (kdata != stack_kdata)
903 		kfree(kdata);
904 	if (retcode)
905 		DRM_DEBUG("comm=\"%s\", pid=%d, ret=%d\n", current->comm,
906 			  task_pid_nr(current), retcode);
907 	return retcode;
908 }
909 EXPORT_SYMBOL(drm_ioctl);
910 
911 /**
912  * drm_ioctl_flags - Check for core ioctl and return ioctl permission flags
913  * @nr: ioctl number
914  * @flags: where to return the ioctl permission flags
915  *
916  * This ioctl is only used by the vmwgfx driver to augment the access checks
917  * done by the drm core and insofar a pretty decent layering violation. This
918  * shouldn't be used by any drivers.
919  *
920  * Returns:
921  * True if the @nr corresponds to a DRM core ioctl number, false otherwise.
922  */
drm_ioctl_flags(unsigned int nr,unsigned int * flags)923 bool drm_ioctl_flags(unsigned int nr, unsigned int *flags)
924 {
925 	if (nr >= DRM_COMMAND_BASE && nr < DRM_COMMAND_END)
926 		return false;
927 
928 	if (nr >= DRM_CORE_IOCTL_COUNT)
929 		return false;
930 	nr = array_index_nospec(nr, DRM_CORE_IOCTL_COUNT);
931 
932 	*flags = drm_ioctls[nr].flags;
933 	return true;
934 }
935 EXPORT_SYMBOL(drm_ioctl_flags);
936