58  *  - GET_UNIQUE ioctl, implemented by drm_getunique is wrapped up in libdrm
60  *  - The libdrm drmSetBusid function is backed by the SET_UNIQUE ioctl. All
62  *  - The internal set_busid kernel functions and driver callbacks are
65  *  - Other ioctls and functions involved are named consistently.
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.
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,
81  *    the next device node.
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
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
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.
109  * \param inode device inode.
115  * Copies the bus id from drm_device::unique into user space.
123 	mutex_lock(&dev->master_mutex);  in drm_getunique()
124 	master = file_priv->master;  in drm_getunique()
125 	if (u->unique_len >= master->unique_len) {  in drm_getunique()
126 		if (copy_to_user(u->unique, master->unique, master->unique_len)) {  in drm_getunique()
127 			mutex_unlock(&dev->master_mutex);  in drm_getunique()
128 			return -EFAULT;  in drm_getunique()
131 	u->unique_len = master->unique_len;  in drm_getunique()
132 	mutex_unlock(&dev->master_mutex);  in drm_getunique()
141 	kfree(master->unique);  in drm_unset_busid()
142 	master->unique = NULL;  in drm_unset_busid()
143 	master->unique_len = 0;  in drm_unset_busid()
148 	struct drm_master *master = file_priv->master;  in drm_set_busid()
151 	if (master->unique != NULL)  in drm_set_busid()
154 	if (dev->dev && dev_is_pci(dev->dev)) {  in drm_set_busid()
161 		WARN_ON(!dev->unique);  in drm_set_busid()
162 		master->unique = kstrdup(dev->unique, GFP_KERNEL);  in drm_set_busid()
163 		if (master->unique)  in drm_set_busid()
164 			master->unique_len = strlen(dev->unique);  in drm_set_busid()
173  * \param inode device inode.
189 	 * Hollowed-out getclient ioctl to keep some dead old drm tests/tools  in drm_getclient()
191 	 * get -EINVAL, hence this is the return value we need to hand back for  in drm_getclient()
199 	if (client->idx == 0) {  in drm_getclient()
200 		client->auth = file_priv->authenticated;  in drm_getclient()
201 		client->pid = task_pid_vnr(current);  in drm_getclient()
202 		client->uid = overflowuid;  in drm_getclient()
203 		client->magic = 0;  in drm_getclient()
204 		client->iocs = 0;  in drm_getclient()
208 		return -EINVAL;  in drm_getclient()
215  * \param inode device inode.
234  * Get device/driver capabilities
241 	req->value = 0;  in drm_getcap()
243 	/* Only some caps make sense with UMS/render-only drivers. */  in drm_getcap()
244 	switch (req->capability) {  in drm_getcap()
246 		req->value = 1;  in drm_getcap()
249 		req->value |= dev->driver->prime_fd_to_handle ? DRM_PRIME_CAP_IMPORT : 0;  in drm_getcap()
250 		req->value |= dev->driver->prime_handle_to_fd ? DRM_PRIME_CAP_EXPORT : 0;  in drm_getcap()
253 		req->value = drm_core_check_feature(dev, DRIVER_SYNCOBJ);  in drm_getcap()
256 		req->value = drm_core_check_feature(dev, DRIVER_SYNCOBJ_TIMELINE);  in drm_getcap()
262 		return -EOPNOTSUPP;  in drm_getcap()
264 	switch (req->capability) {  in drm_getcap()
266 		if (dev->driver->dumb_create)  in drm_getcap()
267 			req->value = 1;  in drm_getcap()
270 		req->value = 1;  in drm_getcap()
273 		req->value = dev->mode_config.preferred_depth;  in drm_getcap()
276 		req->value = dev->mode_config.prefer_shadow;  in drm_getcap()
279 		req->value = dev->mode_config.async_page_flip;  in drm_getcap()
282 		req->value = 1;  in drm_getcap()
284 			if (!crtc->funcs->page_flip_target)  in drm_getcap()
285 				req->value = 0;  in drm_getcap()
289 		if (dev->mode_config.cursor_width)  in drm_getcap()
290 			req->value = dev->mode_config.cursor_width;  in drm_getcap()
292 			req->value = 64;  in drm_getcap()
295 		if (dev->mode_config.cursor_height)  in drm_getcap()
296 			req->value = dev->mode_config.cursor_height;  in drm_getcap()
298 			req->value = 64;  in drm_getcap()
301 		req->value = dev->mode_config.allow_fb_modifiers;  in drm_getcap()
304 		req->value = 1;  in drm_getcap()
307 		return -EINVAL;  in drm_getcap()
313  * Set device/driver capabilities
320 	/* No render-only settable capabilities for now */  in drm_setclientcap()
324 		return -EOPNOTSUPP;  in drm_setclientcap()
326 	switch (req->capability) {  in drm_setclientcap()
328 		if (req->value > 1)  in drm_setclientcap()
329 			return -EINVAL;  in drm_setclientcap()
330 		file_priv->stereo_allowed = req->value;  in drm_setclientcap()
333 		if (req->value > 1)  in drm_setclientcap()
334 			return -EINVAL;  in drm_setclientcap()
335 		file_priv->universal_planes = req->value;  in drm_setclientcap()
339 			return -EOPNOTSUPP;  in drm_setclientcap()
341 		if (current->comm[0] == 'X' && req->value == 1) {  in drm_setclientcap()
343 			return -EOPNOTSUPP;  in drm_setclientcap()
345 		if (req->value > 2)  in drm_setclientcap()
346 			return -EINVAL;  in drm_setclientcap()
347 		file_priv->atomic = req->value;  in drm_setclientcap()
348 		file_priv->universal_planes = req->value;  in drm_setclientcap()
350 		 * No atomic user-space blows up on aspect ratio mode bits.  in drm_setclientcap()
352 		file_priv->aspect_ratio_allowed = req->value;  in drm_setclientcap()
355 		if (req->value > 1)  in drm_setclientcap()
356 			return -EINVAL;  in drm_setclientcap()
357 		file_priv->aspect_ratio_allowed = req->value;  in drm_setclientcap()
360 		if (!file_priv->atomic)  in drm_setclientcap()
361 			return -EINVAL;  in drm_setclientcap()
362 		if (req->value > 1)  in drm_setclientcap()
363 			return -EINVAL;  in drm_setclientcap()
364 		file_priv->writeback_connectors = req->value;  in drm_setclientcap()
367 		return -EINVAL;  in drm_setclientcap()
376  * \param inode device inode.
389 	mutex_lock(&dev->master_mutex);  in drm_setversion()
390 	if (sv->drm_di_major != -1) {  in drm_setversion()
391 		if (sv->drm_di_major != DRM_IF_MAJOR ||  in drm_setversion()
392 		    sv->drm_di_minor < 0 || sv->drm_di_minor > DRM_IF_MINOR) {  in drm_setversion()
393 			retcode = -EINVAL;  in drm_setversion()
396 		if_version = DRM_IF_VERSION(sv->drm_di_major,  in drm_setversion()
397 					    sv->drm_di_minor);  in drm_setversion()
398 		dev->if_version = max(if_version, dev->if_version);  in drm_setversion()
399 		if (sv->drm_di_minor >= 1) {  in drm_setversion()
401 			 * Version 1.1 includes tying of DRM to specific device  in drm_setversion()
410 	if (sv->drm_dd_major != -1) {  in drm_setversion()
411 		if (sv->drm_dd_major != dev->driver->major ||  in drm_setversion()
412 		    sv->drm_dd_minor < 0 || sv->drm_dd_minor >  in drm_setversion()
413 		    dev->driver->minor) {  in drm_setversion()
414 			retcode = -EINVAL;  in drm_setversion()
420 	sv->drm_di_major = DRM_IF_MAJOR;  in drm_setversion()
421 	sv->drm_di_minor = DRM_IF_MINOR;  in drm_setversion()
422 	sv->drm_dd_major = dev->driver->major;  in drm_setversion()
423 	sv->drm_dd_minor = dev->driver->minor;  in drm_setversion()
424 	mutex_unlock(&dev->master_mutex);  in drm_setversion()
430  * drm_noop - DRM no-op ioctl implemntation
431  * @dev: DRM device for the ioctl
435  * This no-op implementation for drm ioctls is useful for deprecated
450  * drm_invalid_op - DRM invalid ioctl implemntation
451  * @dev: DRM device for the ioctl
455  * This no-op implementation for drm ioctls is useful for deprecated
462  * Always fails with a return value of -EINVAL.
467 	return -EINVAL;  in drm_invalid_op()
490 	 * larger than the userspace-supplied buffer) */  in drm_copy_field()
496 			return -EFAULT;  in drm_copy_field()
503  * \param inode device inode.
517 	version->version_major = dev->driver->major;  in drm_version()
518 	version->version_minor = dev->driver->minor;  in drm_version()
519 	version->version_patchlevel = dev->driver->patchlevel;  in drm_version()
520 	err = drm_copy_field(version->name, &version->name_len,  in drm_version()
521 			dev->driver->name);  in drm_version()
523 		err = drm_copy_field(version->date, &version->date_len,  in drm_version()
524 				dev->driver->date);  in drm_version()
526 		err = drm_copy_field(version->desc, &version->desc_len,  in drm_version()
527 				dev->driver->desc);  in drm_version()
533  * drm_ioctl_permit - Check ioctl permissions against caller
542  * Zero if allowed, -EACCES otherwise.
548 		return -EACCES;  in drm_ioctl_permit()
552 		     !file_priv->authenticated))  in drm_ioctl_permit()
553 		return -EACCES;  in drm_ioctl_permit()
558 		return -EACCES;  in drm_ioctl_permit()
563 		return -EACCES;  in drm_ioctl_permit()
751  * ``Documentation/process/botching-up-ioctls.rst``. Note that drm_ioctl()
752  * automatically zero-extends structures, hence make sure you can add more stuff
774  * the driver-specific IOCTLs are wired up.
780 	struct drm_file *file_priv = file->private_data;  in drm_ioctl_kernel()
781 	struct drm_device *dev = file_priv->minor->dev;  in drm_ioctl_kernel()
785 		return -ENODEV;  in drm_ioctl_kernel()
805  * drm_ioctl - ioctl callback implementation for DRM drivers
820 	struct drm_file *file_priv = filp->private_data;  in drm_ioctl()
825 	int retcode = -EINVAL;  in drm_ioctl()
831 	dev = file_priv->minor->dev;  in drm_ioctl()
834 		return -ENODEV;  in drm_ioctl()
837                return -ENOTTY;  in drm_ioctl()
843 		unsigned int index = nr - DRM_COMMAND_BASE;  in drm_ioctl()
845 		if (index >= dev->driver->num_ioctls)  in drm_ioctl()
847 		index = array_index_nospec(index, dev->driver->num_ioctls);  in drm_ioctl()
848 		ioctl = &dev->driver->ioctls[index];  in drm_ioctl()
857 	drv_size = _IOC_SIZE(ioctl->cmd);  in drm_ioctl()
859 	if ((cmd & ioctl->cmd & IOC_IN) == 0)  in drm_ioctl()
861 	if ((cmd & ioctl->cmd & IOC_OUT) == 0)  in drm_ioctl()
866 		  current->comm, task_pid_nr(current),  in drm_ioctl()
867 		  (long)old_encode_dev(file_priv->minor->kdev->devt),  in drm_ioctl()
868 		  file_priv->authenticated, ioctl->name);  in drm_ioctl()
871 	func = ioctl->func;  in drm_ioctl()
875 		retcode = -EINVAL;  in drm_ioctl()
884 			retcode = -ENOMEM;  in drm_ioctl()
890 		retcode = -EFAULT;  in drm_ioctl()
895 		memset(kdata + in_size, 0, ksize - in_size);  in drm_ioctl()
897 	retcode = drm_ioctl_kernel(filp, func, kdata, ioctl->flags);  in drm_ioctl()
899 		retcode = -EFAULT;  in drm_ioctl()
904 			  current->comm, task_pid_nr(current),  in drm_ioctl()
905 			  (long)old_encode_dev(file_priv->minor->kdev->devt),  in drm_ioctl()
906 			  file_priv->authenticated, cmd, nr);  in drm_ioctl()
911 		DRM_DEBUG("comm=\"%s\", pid=%d, ret=%d\n", current->comm,  in drm_ioctl()
918  * drm_ioctl_flags - Check for core ioctl and return ioctl permission flags