52  *  - GET_UNIQUE ioctl, implemented by drm_getunique is wrapped up in libdrm
54  *  - The libdrm drmSetBusid function is backed by the SET_UNIQUE ioctl. All
56  *  - The internal set_busid kernel functions and driver callbacks are
59  *  - Other ioctls and functions involved are named consistently.
66  * Now the actual horror story of how device lookup in drm works. At large,
67  * there's 2 different ways, either by busid, or by device driver name.
72  *    side-effect this fills out the unique name in the master structure.
73  * 2. Call GET_UNIQUE to read out the unique name from the master structure,
75  *    the next device node.
81  *    means the the unique name for the master node just opening is _not_ filled
82  *    out. This despite that with current drm device nodes are always bound to
83  *    one device, and can't be runtime assigned like with drm 1.0.
84  * 2. Match driver name. If it mismatches, proceed to the next device node.
85  * 3. Call GET_UNIQUE, and check whether the unique name has length zero (by
87  *    libdrm skips and proceeds to the next device node. Probably this is just
88  *    copypasta from drm 1.0 times where a set unique name meant that the driver
92  * _not_ return a unique string when SET_VERSION hasn't been called yet,
93  * otherwise libdrm breaks. Even when that unique string can't ever change, and
94  * is totally irrelevant for actually opening the device because runtime
95  * assignable device instances were only support in drm 1.0, which is long dead.
103  * \param inode device inode.
109  * Copies the bus id from drm_device::unique into user space.
115 	struct drm_master *master = file_priv->master;  in drm_getunique()
117 	mutex_lock(&master->dev->master_mutex);  in drm_getunique()
118 	if (u->unique_len >= master->unique_len) {  in drm_getunique()
119 		if (copy_to_user(u->unique, master->unique, master->unique_len)) {  in drm_getunique()
120 			mutex_unlock(&master->dev->master_mutex);  in drm_getunique()
121 			return -EFAULT;  in drm_getunique()
124 	u->unique_len = master->unique_len;  in drm_getunique()
125 	mutex_unlock(&master->dev->master_mutex);  in drm_getunique()
134 	kfree(master->unique);  in drm_unset_busid()
135 	master->unique = NULL;  in drm_unset_busid()
136 	master->unique_len = 0;  in drm_unset_busid()
141 	struct drm_master *master = file_priv->master;  in drm_set_busid()
144 	if (master->unique != NULL)  in drm_set_busid()
147 	if (dev->dev && dev_is_pci(dev->dev)) {  in drm_set_busid()
154 		WARN_ON(!dev->unique);  in drm_set_busid()
155 		master->unique = kstrdup(dev->unique, GFP_KERNEL);  in drm_set_busid()
156 		if (master->unique)  in drm_set_busid()
157 			master->unique_len = strlen(dev->unique);  in drm_set_busid()
166  * \param inode device inode.
182 	 * Hollowed-out getclient ioctl to keep some dead old drm tests/tools  in drm_getclient()
184 	 * get -EINVAL, hence this is the return value we need to hand back for  in drm_getclient()
192 	if (client->idx == 0) {  in drm_getclient()
193 		client->auth = file_priv->authenticated;  in drm_getclient()
194 		client->pid = task_pid_vnr(current);  in drm_getclient()
195 		client->uid = overflowuid;  in drm_getclient()
196 		client->magic = 0;  in drm_getclient()
197 		client->iocs = 0;  in drm_getclient()
201 		return -EINVAL;  in drm_getclient()
208  * \param inode device inode.
227  * Get device/driver capabilities
234 	req->value = 0;  in drm_getcap()
236 	/* Only some caps make sense with UMS/render-only drivers. */  in drm_getcap()
237 	switch (req->capability) {  in drm_getcap()
239 		req->value = 1;  in drm_getcap()
242 		req->value |= dev->driver->prime_fd_to_handle ? DRM_PRIME_CAP_IMPORT : 0;  in drm_getcap()
243 		req->value |= dev->driver->prime_handle_to_fd ? DRM_PRIME_CAP_EXPORT : 0;  in drm_getcap()
246 		req->value = drm_core_check_feature(dev, DRIVER_SYNCOBJ);  in drm_getcap()
252 		return -ENOTSUPP;  in drm_getcap()
254 	switch (req->capability) {  in drm_getcap()
256 		if (dev->driver->dumb_create)  in drm_getcap()
257 			req->value = 1;  in drm_getcap()
260 		req->value = 1;  in drm_getcap()
263 		req->value = dev->mode_config.preferred_depth;  in drm_getcap()
266 		req->value = dev->mode_config.prefer_shadow;  in drm_getcap()
269 		req->value = dev->mode_config.async_page_flip;  in drm_getcap()
272 		req->value = 1;  in drm_getcap()
274 			if (!crtc->funcs->page_flip_target)  in drm_getcap()
275 				req->value = 0;  in drm_getcap()
279 		if (dev->mode_config.cursor_width)  in drm_getcap()
280 			req->value = dev->mode_config.cursor_width;  in drm_getcap()
282 			req->value = 64;  in drm_getcap()
285 		if (dev->mode_config.cursor_height)  in drm_getcap()
286 			req->value = dev->mode_config.cursor_height;  in drm_getcap()
288 			req->value = 64;  in drm_getcap()
291 		req->value = dev->mode_config.allow_fb_modifiers;  in drm_getcap()
294 		req->value = 1;  in drm_getcap()
297 		return -EINVAL;  in drm_getcap()
303  * Set device/driver capabilities
310 	switch (req->capability) {  in drm_setclientcap()
312 		if (req->value > 1)  in drm_setclientcap()
313 			return -EINVAL;  in drm_setclientcap()
314 		file_priv->stereo_allowed = req->value;  in drm_setclientcap()
317 		if (req->value > 1)  in drm_setclientcap()
318 			return -EINVAL;  in drm_setclientcap()
319 		file_priv->universal_planes = req->value;  in drm_setclientcap()
323 			return -EINVAL;  in drm_setclientcap()
325 		if (current->comm[0] == 'X' && req->value == 1) {  in drm_setclientcap()
327 			return -EOPNOTSUPP;  in drm_setclientcap()
329 		if (req->value > 2)  in drm_setclientcap()
330 			return -EINVAL;  in drm_setclientcap()
331 		file_priv->atomic = req->value;  in drm_setclientcap()
332 		file_priv->universal_planes = req->value;  in drm_setclientcap()
334 		 * No atomic user-space blows up on aspect ratio mode bits.  in drm_setclientcap()
336 		file_priv->aspect_ratio_allowed = req->value;  in drm_setclientcap()
339 		if (req->value > 1)  in drm_setclientcap()
340 			return -EINVAL;  in drm_setclientcap()
341 		file_priv->aspect_ratio_allowed = req->value;  in drm_setclientcap()
344 		if (!file_priv->atomic)  in drm_setclientcap()
345 			return -EINVAL;  in drm_setclientcap()
346 		if (req->value > 1)  in drm_setclientcap()
347 			return -EINVAL;  in drm_setclientcap()
348 		file_priv->writeback_connectors = req->value;  in drm_setclientcap()
351 		return -EINVAL;  in drm_setclientcap()
360  * \param inode device inode.
373 	mutex_lock(&dev->master_mutex);  in drm_setversion()
374 	if (sv->drm_di_major != -1) {  in drm_setversion()
375 		if (sv->drm_di_major != DRM_IF_MAJOR ||  in drm_setversion()
376 		    sv->drm_di_minor < 0 || sv->drm_di_minor > DRM_IF_MINOR) {  in drm_setversion()
377 			retcode = -EINVAL;  in drm_setversion()
380 		if_version = DRM_IF_VERSION(sv->drm_di_major,  in drm_setversion()
381 					    sv->drm_di_minor);  in drm_setversion()
382 		dev->if_version = max(if_version, dev->if_version);  in drm_setversion()
383 		if (sv->drm_di_minor >= 1) {  in drm_setversion()
385 			 * Version 1.1 includes tying of DRM to specific device  in drm_setversion()
394 	if (sv->drm_dd_major != -1) {  in drm_setversion()
395 		if (sv->drm_dd_major != dev->driver->major ||  in drm_setversion()
396 		    sv->drm_dd_minor < 0 || sv->drm_dd_minor >  in drm_setversion()
397 		    dev->driver->minor) {  in drm_setversion()
398 			retcode = -EINVAL;  in drm_setversion()
404 	sv->drm_di_major = DRM_IF_MAJOR;  in drm_setversion()
405 	sv->drm_di_minor = DRM_IF_MINOR;  in drm_setversion()
406 	sv->drm_dd_major = dev->driver->major;  in drm_setversion()
407 	sv->drm_dd_minor = dev->driver->minor;  in drm_setversion()
408 	mutex_unlock(&dev->master_mutex);  in drm_setversion()
414  * drm_noop - DRM no-op ioctl implemntation
415  * @dev: DRM device for the ioctl
419  * This no-op implementation for drm ioctls is useful for deprecated
434  * drm_invalid_op - DRM invalid ioctl implemntation
435  * @dev: DRM device for the ioctl
439  * This no-op implementation for drm ioctls is useful for deprecated
446  * Always fails with a return value of -EINVAL.
451 	return -EINVAL;  in drm_invalid_op()
468 	 * larger than the userspace-supplied buffer) */  in drm_copy_field()
474 			return -EFAULT;  in drm_copy_field()
481  * \param inode device inode.
495 	version->version_major = dev->driver->major;  in drm_version()
496 	version->version_minor = dev->driver->minor;  in drm_version()
497 	version->version_patchlevel = dev->driver->patchlevel;  in drm_version()
498 	err = drm_copy_field(version->name, &version->name_len,  in drm_version()
499 			dev->driver->name);  in drm_version()
501 		err = drm_copy_field(version->date, &version->date_len,  in drm_version()
502 				dev->driver->date);  in drm_version()
504 		err = drm_copy_field(version->desc, &version->desc_len,  in drm_version()
505 				dev->driver->desc);  in drm_version()
511  * drm_ioctl_permit - Check ioctl permissions against caller
520  * Zero if allowed, -EACCES otherwise.
526 		return -EACCES;  in drm_ioctl_permit()
530 		     !file_priv->authenticated))  in drm_ioctl_permit()
531 		return -EACCES;  in drm_ioctl_permit()
536 		return -EACCES;  in drm_ioctl_permit()
541 		return -EACCES;  in drm_ioctl_permit()
714  * ``Documentation/ioctl/botching-up-ioctls.txt``. Note that drm_ioctl()
715  * automatically zero-extends structures, hence make sure you can add more stuff
737  * the driver-specific IOCTLs are wired up.
743 	struct drm_file *file_priv = file->private_data;  in drm_ioctl_kernel()
744 	struct drm_device *dev = file_priv->minor->dev;  in drm_ioctl_kernel()
748 		return -ENODEV;  in drm_ioctl_kernel()
768  * drm_ioctl - ioctl callback implementation for DRM drivers
783 	struct drm_file *file_priv = filp->private_data;  in drm_ioctl()
788 	int retcode = -EINVAL;  in drm_ioctl()
794 	dev = file_priv->minor->dev;  in drm_ioctl()
797 		return -ENODEV;  in drm_ioctl()
803 		unsigned int index = nr - DRM_COMMAND_BASE;  in drm_ioctl()
805 		if (index >= dev->driver->num_ioctls)  in drm_ioctl()
807 		index = array_index_nospec(index, dev->driver->num_ioctls);  in drm_ioctl()
808 		ioctl = &dev->driver->ioctls[index];  in drm_ioctl()
817 	drv_size = _IOC_SIZE(ioctl->cmd);  in drm_ioctl()
819 	if ((cmd & ioctl->cmd & IOC_IN) == 0)  in drm_ioctl()
821 	if ((cmd & ioctl->cmd & IOC_OUT) == 0)  in drm_ioctl()
827 		  (long)old_encode_dev(file_priv->minor->kdev->devt),  in drm_ioctl()
828 		  file_priv->authenticated, ioctl->name);  in drm_ioctl()
831 	func = ioctl->func;  in drm_ioctl()
835 		retcode = -EINVAL;  in drm_ioctl()
844 			retcode = -ENOMEM;  in drm_ioctl()
850 		retcode = -EFAULT;  in drm_ioctl()
855 		memset(kdata + in_size, 0, ksize - in_size);  in drm_ioctl()
857 	retcode = drm_ioctl_kernel(filp, func, kdata, ioctl->flags);  in drm_ioctl()
859 		retcode = -EFAULT;  in drm_ioctl()
865 			  (long)old_encode_dev(file_priv->minor->kdev->devt),  in drm_ioctl()
866 			  file_priv->authenticated, cmd, nr);  in drm_ioctl()
877  * drm_ioctl_flags - Check for core ioctl and return ioctl permission flags