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oss.c

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  • drm_ioctl.c 26.68 KiB
    /*
     * Created: Fri Jan  8 09:01:26 1999 by faith@valinux.com
     *
     * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
     * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
     * All Rights Reserved.
     *
     * Author Rickard E. (Rik) Faith <faith@valinux.com>
     * Author Gareth Hughes <gareth@valinux.com>
     *
     * Permission is hereby granted, free of charge, to any person obtaining a
     * copy of this software and associated documentation files (the "Software"),
     * to deal in the Software without restriction, including without limitation
     * the rights to use, copy, modify, merge, publish, distribute, sublicense,
     * and/or sell copies of the Software, and to permit persons to whom the
     * Software is furnished to do so, subject to the following conditions:
     *
     * The above copyright notice and this permission notice (including the next
     * paragraph) shall be included in all copies or substantial portions of the
     * Software.
     *
     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
     * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
     * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     * OTHER DEALINGS IN THE SOFTWARE.
     */
    
    #include <drm/drmP.h>
    #include <drm/drm_auth.h>
    #include "drm_legacy.h"
    #include "drm_internal.h"
    #include "drm_crtc_internal.h"
    
    #include <linux/pci.h>
    #include <linux/export.h>
    
    /**
     * DOC: getunique and setversion story
     *
     * BEWARE THE DRAGONS! MIND THE TRAPDOORS!
     *
     * In an attempt to warn anyone else who's trying to figure out what's going
     * on here, I'll try to summarize the story. First things first, let's clear up
     * the names, because the kernel internals, libdrm and the ioctls are all named
     * differently:
     *
     *  - GET_UNIQUE ioctl, implemented by drm_getunique is wrapped up in libdrm
     *    through the drmGetBusid function.
     *  - The libdrm drmSetBusid function is backed by the SET_UNIQUE ioctl. All
     *    that code is nerved in the kernel with drm_invalid_op().
     *  - The internal set_busid kernel functions and driver callbacks are
     *    exclusively use by the SET_VERSION ioctl, because only drm 1.0 (which is
     *    nerved) allowed userspace to set the busid through the above ioctl.
     *  - Other ioctls and functions involved are named consistently.
     *
     * For anyone wondering what's the difference between drm 1.1 and 1.4: Correctly
     * handling pci domains in the busid on ppc. Doing this correctly was only
     * implemented in libdrm in 2010, hence can't be nerved yet. No one knows what's
     * special with drm 1.2 and 1.3.
     *
     * Now the actual horror story of how device lookup in drm works. At large,
     * there's 2 different ways, either by busid, or by device driver name.
     *
     * Opening by busid is fairly simple:
     *
     * 1. First call SET_VERSION to make sure pci domains are handled properly. As a
     *    side-effect this fills out the unique name in the master structure.
     * 2. Call GET_UNIQUE to read out the unique name from the master structure,
     *    which matches the busid thanks to step 1. If it doesn't, proceed to try
     *    the next device node.
     *
     * Opening by name is slightly different:
     *
     * 1. Directly call VERSION to get the version and to match against the driver
     *    name returned by that ioctl. Note that SET_VERSION is not called, which
     *    means the the unique name for the master node just opening is _not_ filled
     *    out. This despite that with current drm device nodes are always bound to
     *    one device, and can't be runtime assigned like with drm 1.0.
     * 2. Match driver name. If it mismatches, proceed to the next device node.
     * 3. Call GET_UNIQUE, and check whether the unique name has length zero (by
     *    checking that the first byte in the string is 0). If that's not the case
     *    libdrm skips and proceeds to the next device node. Probably this is just
     *    copypasta from drm 1.0 times where a set unique name meant that the driver
     *    was in use already, but that's just conjecture.
     *
     * Long story short: To keep the open by name logic working, GET_UNIQUE must
     * _not_ return a unique string when SET_VERSION hasn't been called yet,
     * otherwise libdrm breaks. Even when that unique string can't ever change, and
     * is totally irrelevant for actually opening the device because runtime
     * assignable device instances were only support in drm 1.0, which is long dead.
     * But the libdrm code in drmOpenByName somehow survived, hence this can't be
     * broken.
     */
    
    static int drm_version(struct drm_device *dev, void *data,
    		       struct drm_file *file_priv);
    
    /*
     * Get the bus id.
     *
     * \param inode device inode.
     * \param file_priv DRM file private.
     * \param cmd command.
     * \param arg user argument, pointing to a drm_unique structure.
     * \return zero on success or a negative number on failure.
     *
     * Copies the bus id from drm_device::unique into user space.
     */
    static int drm_getunique(struct drm_device *dev, void *data,
    		  struct drm_file *file_priv)
    {
    	struct drm_unique *u = data;
    	struct drm_master *master = file_priv->master;
    
    	if (u->unique_len >= master->unique_len) {
    		if (copy_to_user(u->unique, master->unique, master->unique_len))
    			return -EFAULT;
    	}
    	u->unique_len = master->unique_len;
    
    	return 0;
    }
    
    static void
    drm_unset_busid(struct drm_device *dev,
    		struct drm_master *master)
    {
    	kfree(master->unique);
    	master->unique = NULL;
    	master->unique_len = 0;
    }
    
    static int drm_set_busid(struct drm_device *dev, struct drm_file *file_priv)
    {
    	struct drm_master *master = file_priv->master;
    	int ret;
    
    	if (master->unique != NULL)
    		drm_unset_busid(dev, master);
    
    	if (dev->driver->set_busid) {
    		ret = dev->driver->set_busid(dev, master);
    		if (ret) {
    			drm_unset_busid(dev, master);
    			return ret;
    		}
    	} else {
    		WARN_ON(!dev->unique);
    		master->unique = kstrdup(dev->unique, GFP_KERNEL);
    		if (master->unique)
    			master->unique_len = strlen(dev->unique);
    	}
    
    	return 0;
    }
    
    /*
     * Get client information.
     *
     * \param inode device inode.
     * \param file_priv DRM file private.
     * \param cmd command.
     * \param arg user argument, pointing to a drm_client structure.
     *
     * \return zero on success or a negative number on failure.
     *
     * Searches for the client with the specified index and copies its information
     * into userspace
     */
    static int drm_getclient(struct drm_device *dev, void *data,
    		  struct drm_file *file_priv)
    {
    	struct drm_client *client = data;
    
    	/*
    	 * Hollowed-out getclient ioctl to keep some dead old drm tests/tools
    	 * not breaking completely. Userspace tools stop enumerating one they
    	 * get -EINVAL, hence this is the return value we need to hand back for
    	 * no clients tracked.
    	 *
    	 * Unfortunately some clients (*cough* libva *cough*) use this in a fun
    	 * attempt to figure out whether they're authenticated or not. Since
    	 * that's the only thing they care about, give it to the directly
    	 * instead of walking one giant list.
    	 */
    	if (client->idx == 0) {
    		client->auth = file_priv->authenticated;
    		client->pid = task_pid_vnr(current);
    		client->uid = overflowuid;
    		client->magic = 0;
    		client->iocs = 0;
    
    		return 0;
    	} else {
    		return -EINVAL;
    	}
    }
    
    /*
     * Get statistics information.
     *
     * \param inode device inode.
     * \param file_priv DRM file private.
     * \param cmd command.
     * \param arg user argument, pointing to a drm_stats structure.
     *
     * \return zero on success or a negative number on failure.
     */
    static int drm_getstats(struct drm_device *dev, void *data,
    		 struct drm_file *file_priv)
    {
    	struct drm_stats *stats = data;
    
    	/* Clear stats to prevent userspace from eating its stack garbage. */
    	memset(stats, 0, sizeof(*stats));
    
    	return 0;
    }
    
    /*
     * Get device/driver capabilities
     */
    static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_priv)
    {
    	struct drm_get_cap *req = data;
    	struct drm_crtc *crtc;
    
    	req->value = 0;
    	switch (req->capability) {
    	case DRM_CAP_DUMB_BUFFER:
    		if (dev->driver->dumb_create)
    			req->value = 1;
    		break;
    	case DRM_CAP_VBLANK_HIGH_CRTC:
    		req->value = 1;
    		break;
    	case DRM_CAP_DUMB_PREFERRED_DEPTH:
    		req->value = dev->mode_config.preferred_depth;
    		break;
    	case DRM_CAP_DUMB_PREFER_SHADOW:
    		req->value = dev->mode_config.prefer_shadow;
    		break;
    	case DRM_CAP_PRIME:
    		req->value |= dev->driver->prime_fd_to_handle ? DRM_PRIME_CAP_IMPORT : 0;
    		req->value |= dev->driver->prime_handle_to_fd ? DRM_PRIME_CAP_EXPORT : 0;
    		break;
    	case DRM_CAP_TIMESTAMP_MONOTONIC:
    		req->value = drm_timestamp_monotonic;
    		break;
    	case DRM_CAP_ASYNC_PAGE_FLIP:
    		req->value = dev->mode_config.async_page_flip;
    		break;
    	case DRM_CAP_PAGE_FLIP_TARGET:
    		if (drm_core_check_feature(dev, DRIVER_MODESET)) {
    			req->value = 1;
    			drm_for_each_crtc(crtc, dev) {
    				if (!crtc->funcs->page_flip_target)
    					req->value = 0;
    			}
    		}
    		break;
    	case DRM_CAP_CURSOR_WIDTH:
    		if (dev->mode_config.cursor_width)
    			req->value = dev->mode_config.cursor_width;
    		else
    			req->value = 64;
    		break;
    	case DRM_CAP_CURSOR_HEIGHT:
    		if (dev->mode_config.cursor_height)
    			req->value = dev->mode_config.cursor_height;
    		else
    			req->value = 64;
    		break;
    	case DRM_CAP_ADDFB2_MODIFIERS:
    		req->value = dev->mode_config.allow_fb_modifiers;
    		break;
    	default:
    		return -EINVAL;
    	}
    	return 0;
    }
    
    /*
     * Set device/driver capabilities
     */
    static int
    drm_setclientcap(struct drm_device *dev, void *data, struct drm_file *file_priv)
    {
    	struct drm_set_client_cap *req = data;
    
    	switch (req->capability) {
    	case DRM_CLIENT_CAP_STEREO_3D:
    		if (req->value > 1)
    			return -EINVAL;
    		file_priv->stereo_allowed = req->value;
    		break;
    	case DRM_CLIENT_CAP_UNIVERSAL_PLANES:
    		if (req->value > 1)
    			return -EINVAL;
    		file_priv->universal_planes = req->value;
    		break;
    	case DRM_CLIENT_CAP_ATOMIC:
    		if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
    			return -EINVAL;
    		if (req->value > 1)
    			return -EINVAL;
    		file_priv->atomic = req->value;
    		file_priv->universal_planes = req->value;
    		break;
    	default:
    		return -EINVAL;
    	}
    
    	return 0;
    }
    
    /*
     * Setversion ioctl.
     *
     * \param inode device inode.
     * \param file_priv DRM file private.
     * \param cmd command.
     * \param arg user argument, pointing to a drm_lock structure.
     * \return zero on success or negative number on failure.
     *
     * Sets the requested interface version
     */
    static int drm_setversion(struct drm_device *dev, void *data, struct drm_file *file_priv)
    {
    	struct drm_set_version *sv = data;
    	int if_version, retcode = 0;
    
    	if (sv->drm_di_major != -1) {
    		if (sv->drm_di_major != DRM_IF_MAJOR ||
    		    sv->drm_di_minor < 0 || sv->drm_di_minor > DRM_IF_MINOR) {
    			retcode = -EINVAL;
    			goto done;
    		}
    		if_version = DRM_IF_VERSION(sv->drm_di_major,
    					    sv->drm_di_minor);
    		dev->if_version = max(if_version, dev->if_version);
    		if (sv->drm_di_minor >= 1) {
    			/*
    			 * Version 1.1 includes tying of DRM to specific device
    			 * Version 1.4 has proper PCI domain support
    			 */
    			retcode = drm_set_busid(dev, file_priv);
    			if (retcode)
    				goto done;
    		}
    	}
    
    	if (sv->drm_dd_major != -1) {
    		if (sv->drm_dd_major != dev->driver->major ||
    		    sv->drm_dd_minor < 0 || sv->drm_dd_minor >
    		    dev->driver->minor) {
    			retcode = -EINVAL;
    			goto done;
    		}
    	}
    
    done:
    	sv->drm_di_major = DRM_IF_MAJOR;
    	sv->drm_di_minor = DRM_IF_MINOR;
    	sv->drm_dd_major = dev->driver->major;
    	sv->drm_dd_minor = dev->driver->minor;
    
    	return retcode;
    }
    
    /**
     * drm_noop - DRM no-op ioctl implemntation
     * @dev: DRM device for the ioctl
     * @data: data pointer for the ioctl
     * @file_priv: DRM file for the ioctl call
     *
     * This no-op implementation for drm ioctls is useful for deprecated
     * functionality where we can't return a failure code because existing userspace
     * checks the result of the ioctl, but doesn't care about the action.
     *
     * Always returns successfully with 0.
     */
    int drm_noop(struct drm_device *dev, void *data,
    	     struct drm_file *file_priv)
    {
    	DRM_DEBUG("\n");
    	return 0;
    }
    EXPORT_SYMBOL(drm_noop);
    
    /**
     * drm_invalid_op - DRM invalid ioctl implemntation
     * @dev: DRM device for the ioctl
     * @data: data pointer for the ioctl
     * @file_priv: DRM file for the ioctl call
     *
     * This no-op implementation for drm ioctls is useful for deprecated
     * functionality where we really don't want to allow userspace to call the ioctl
     * any more. This is the case for old ums interfaces for drivers that
     * transitioned to kms gradually and so kept the old legacy tables around. This
     * only applies to radeon and i915 kms drivers, other drivers shouldn't need to
     * use this function.
     *
     * Always fails with a return value of -EINVAL.
     */
    int drm_invalid_op(struct drm_device *dev, void *data,
    		   struct drm_file *file_priv)
    {
    	return -EINVAL;
    }
    EXPORT_SYMBOL(drm_invalid_op);
    
    /*
     * Copy and IOCTL return string to user space
     */
    static int drm_copy_field(char __user *buf, size_t *buf_len, const char *value)
    {
    	int len;
    
    	/* don't overflow userbuf */
    	len = strlen(value);
    	if (len > *buf_len)
    		len = *buf_len;
    
    	/* let userspace know exact length of driver value (which could be
    	 * larger than the userspace-supplied buffer) */
    	*buf_len = strlen(value);
    
    	/* finally, try filling in the userbuf */
    	if (len && buf)
    		if (copy_to_user(buf, value, len))
    			return -EFAULT;
    	return 0;
    }
    
    /*
     * Get version information
     *
     * \param inode device inode.
     * \param filp file pointer.
     * \param cmd command.
     * \param arg user argument, pointing to a drm_version structure.
     * \return zero on success or negative number on failure.
     *
     * Fills in the version information in \p arg.
     */
    static int drm_version(struct drm_device *dev, void *data,
    		       struct drm_file *file_priv)
    {
    	struct drm_version *version = data;
    	int err;
    
    	version->version_major = dev->driver->major;
    	version->version_minor = dev->driver->minor;
    	version->version_patchlevel = dev->driver->patchlevel;
    	err = drm_copy_field(version->name, &version->name_len,
    			dev->driver->name);
    	if (!err)
    		err = drm_copy_field(version->date, &version->date_len,
    				dev->driver->date);
    	if (!err)
    		err = drm_copy_field(version->desc, &version->desc_len,
    				dev->driver->desc);
    
    	return err;
    }
    
    /*
     * drm_ioctl_permit - Check ioctl permissions against caller
     *
     * @flags: ioctl permission flags.
     * @file_priv: Pointer to struct drm_file identifying the caller.
     *
     * Checks whether the caller is allowed to run an ioctl with the
     * indicated permissions. If so, returns zero. Otherwise returns an
     * error code suitable for ioctl return.
     */
    int drm_ioctl_permit(u32 flags, struct drm_file *file_priv)
    {
    	/* ROOT_ONLY is only for CAP_SYS_ADMIN */
    	if (unlikely((flags & DRM_ROOT_ONLY) && !capable(CAP_SYS_ADMIN)))
    		return -EACCES;
    
    	/* AUTH is only for authenticated or render client */
    	if (unlikely((flags & DRM_AUTH) && !drm_is_render_client(file_priv) &&
    		     !file_priv->authenticated))
    		return -EACCES;
    
    	/* MASTER is only for master or control clients */
    	if (unlikely((flags & DRM_MASTER) && 
    		     !drm_is_current_master(file_priv) &&
    		     !drm_is_control_client(file_priv)))
    		return -EACCES;
    
    	/* Control clients must be explicitly allowed */
    	if (unlikely(!(flags & DRM_CONTROL_ALLOW) &&
    		     drm_is_control_client(file_priv)))
    		return -EACCES;
    
    	/* Render clients must be explicitly allowed */
    	if (unlikely(!(flags & DRM_RENDER_ALLOW) &&
    		     drm_is_render_client(file_priv)))
    		return -EACCES;
    
    	return 0;
    }
    EXPORT_SYMBOL(drm_ioctl_permit);
    
    #define DRM_IOCTL_DEF(ioctl, _func, _flags)	\
    	[DRM_IOCTL_NR(ioctl)] = {		\
    		.cmd = ioctl,			\
    		.func = _func,			\
    		.flags = _flags,		\
    		.name = #ioctl			\
    	}
    
    /* Ioctl table */
    static const struct drm_ioctl_desc drm_ioctls[] = {
    	DRM_IOCTL_DEF(DRM_IOCTL_VERSION, drm_version,
    		      DRM_UNLOCKED|DRM_RENDER_ALLOW|DRM_CONTROL_ALLOW),
    	DRM_IOCTL_DEF(DRM_IOCTL_GET_UNIQUE, drm_getunique, 0),
    	DRM_IOCTL_DEF(DRM_IOCTL_GET_MAGIC, drm_getmagic, DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_IRQ_BUSID, drm_irq_by_busid, DRM_MASTER|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_GET_MAP, drm_legacy_getmap_ioctl, DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_GET_CLIENT, drm_getclient, DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_GET_STATS, drm_getstats, DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_GET_CAP, drm_getcap, DRM_UNLOCKED|DRM_RENDER_ALLOW),
    	DRM_IOCTL_DEF(DRM_IOCTL_SET_CLIENT_CAP, drm_setclientcap, 0),
    	DRM_IOCTL_DEF(DRM_IOCTL_SET_VERSION, drm_setversion, DRM_MASTER),
    
    	DRM_IOCTL_DEF(DRM_IOCTL_SET_UNIQUE, drm_invalid_op, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_BLOCK, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_UNBLOCK, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_AUTH_MAGIC, drm_authmagic, DRM_AUTH|DRM_UNLOCKED|DRM_MASTER),
    
    	DRM_IOCTL_DEF(DRM_IOCTL_ADD_MAP, drm_legacy_addmap_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_RM_MAP, drm_legacy_rmmap_ioctl, DRM_AUTH),
    
    	DRM_IOCTL_DEF(DRM_IOCTL_SET_SAREA_CTX, drm_legacy_setsareactx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_GET_SAREA_CTX, drm_legacy_getsareactx, DRM_AUTH),
    
    	DRM_IOCTL_DEF(DRM_IOCTL_SET_MASTER, drm_setmaster_ioctl, DRM_UNLOCKED|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_DROP_MASTER, drm_dropmaster_ioctl, DRM_UNLOCKED|DRM_ROOT_ONLY),
    
    	DRM_IOCTL_DEF(DRM_IOCTL_ADD_CTX, drm_legacy_addctx, DRM_AUTH|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_RM_CTX, drm_legacy_rmctx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_MOD_CTX, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_GET_CTX, drm_legacy_getctx, DRM_AUTH),
    	DRM_IOCTL_DEF(DRM_IOCTL_SWITCH_CTX, drm_legacy_switchctx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_NEW_CTX, drm_legacy_newctx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_RES_CTX, drm_legacy_resctx, DRM_AUTH),
    
    	DRM_IOCTL_DEF(DRM_IOCTL_ADD_DRAW, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_RM_DRAW, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    
    	DRM_IOCTL_DEF(DRM_IOCTL_LOCK, drm_legacy_lock, DRM_AUTH),
    	DRM_IOCTL_DEF(DRM_IOCTL_UNLOCK, drm_legacy_unlock, DRM_AUTH),
    
    	DRM_IOCTL_DEF(DRM_IOCTL_FINISH, drm_noop, DRM_AUTH),
    
    	DRM_IOCTL_DEF(DRM_IOCTL_ADD_BUFS, drm_legacy_addbufs, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_MARK_BUFS, drm_legacy_markbufs, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_INFO_BUFS, drm_legacy_infobufs, DRM_AUTH),
    	DRM_IOCTL_DEF(DRM_IOCTL_MAP_BUFS, drm_legacy_mapbufs, DRM_AUTH),
    	DRM_IOCTL_DEF(DRM_IOCTL_FREE_BUFS, drm_legacy_freebufs, DRM_AUTH),
    	DRM_IOCTL_DEF(DRM_IOCTL_DMA, drm_legacy_dma_ioctl, DRM_AUTH),
    
    	DRM_IOCTL_DEF(DRM_IOCTL_CONTROL, drm_control, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    
    #if IS_ENABLED(CONFIG_AGP)
    	DRM_IOCTL_DEF(DRM_IOCTL_AGP_ACQUIRE, drm_agp_acquire_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_AGP_RELEASE, drm_agp_release_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_AGP_ENABLE, drm_agp_enable_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_AGP_INFO, drm_agp_info_ioctl, DRM_AUTH),
    	DRM_IOCTL_DEF(DRM_IOCTL_AGP_ALLOC, drm_agp_alloc_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_AGP_FREE, drm_agp_free_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_AGP_BIND, drm_agp_bind_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_AGP_UNBIND, drm_agp_unbind_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    #endif
    
    	DRM_IOCTL_DEF(DRM_IOCTL_SG_ALLOC, drm_legacy_sg_alloc, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    	DRM_IOCTL_DEF(DRM_IOCTL_SG_FREE, drm_legacy_sg_free, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    
    	DRM_IOCTL_DEF(DRM_IOCTL_WAIT_VBLANK, drm_wait_vblank, DRM_UNLOCKED),
    
    	DRM_IOCTL_DEF(DRM_IOCTL_MODESET_CTL, drm_modeset_ctl, 0),
    
    	DRM_IOCTL_DEF(DRM_IOCTL_UPDATE_DRAW, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
    
    	DRM_IOCTL_DEF(DRM_IOCTL_GEM_CLOSE, drm_gem_close_ioctl, DRM_UNLOCKED|DRM_RENDER_ALLOW),
    	DRM_IOCTL_DEF(DRM_IOCTL_GEM_FLINK, drm_gem_flink_ioctl, DRM_AUTH|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_GEM_OPEN, drm_gem_open_ioctl, DRM_AUTH|DRM_UNLOCKED),
    
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETRESOURCES, drm_mode_getresources, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    
    	DRM_IOCTL_DEF(DRM_IOCTL_PRIME_HANDLE_TO_FD, drm_prime_handle_to_fd_ioctl, DRM_AUTH|DRM_UNLOCKED|DRM_RENDER_ALLOW),
    	DRM_IOCTL_DEF(DRM_IOCTL_PRIME_FD_TO_HANDLE, drm_prime_fd_to_handle_ioctl, DRM_AUTH|DRM_UNLOCKED|DRM_RENDER_ALLOW),
    
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPLANERESOURCES, drm_mode_getplane_res, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETCRTC, drm_mode_getcrtc, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETCRTC, drm_mode_setcrtc, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPLANE, drm_mode_getplane, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETPLANE, drm_mode_setplane, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_CURSOR, drm_mode_cursor_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETGAMMA, drm_mode_gamma_get_ioctl, DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETGAMMA, drm_mode_gamma_set_ioctl, DRM_MASTER|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETENCODER, drm_mode_getencoder, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETCONNECTOR, drm_mode_getconnector, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_ATTACHMODE, drm_noop, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_DETACHMODE, drm_noop, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPROPERTY, drm_mode_getproperty_ioctl, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETPROPERTY, drm_mode_connector_property_set_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPROPBLOB, drm_mode_getblob_ioctl, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETFB, drm_mode_getfb, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_ADDFB, drm_mode_addfb, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_ADDFB2, drm_mode_addfb2, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_RMFB, drm_mode_rmfb, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_PAGE_FLIP, drm_mode_page_flip_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_DIRTYFB, drm_mode_dirtyfb_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_CREATE_DUMB, drm_mode_create_dumb_ioctl, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_MAP_DUMB, drm_mode_mmap_dumb_ioctl, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_DESTROY_DUMB, drm_mode_destroy_dumb_ioctl, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_OBJ_GETPROPERTIES, drm_mode_obj_get_properties_ioctl, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_OBJ_SETPROPERTY, drm_mode_obj_set_property_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_CURSOR2, drm_mode_cursor2_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_ATOMIC, drm_mode_atomic_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_CREATEPROPBLOB, drm_mode_createblob_ioctl, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    	DRM_IOCTL_DEF(DRM_IOCTL_MODE_DESTROYPROPBLOB, drm_mode_destroyblob_ioctl, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
    };
    
    #define DRM_CORE_IOCTL_COUNT	ARRAY_SIZE( drm_ioctls )
    
    /**
     * drm_ioctl - ioctl callback implementation for DRM drivers
     * @filp: file this ioctl is called on
     * @cmd: ioctl cmd number
     * @arg: user argument
     *
     * Looks up the ioctl function in the ::ioctls table, checking for root
     * previleges if so required, and dispatches to the respective function.
     *
     * Returns:
     * Zero on success, negative error code on failure.
     */
    long drm_ioctl(struct file *filp,
    	      unsigned int cmd, unsigned long arg)
    {
    	struct drm_file *file_priv = filp->private_data;
    	struct drm_device *dev;
    	const struct drm_ioctl_desc *ioctl = NULL;
    	drm_ioctl_t *func;
    	unsigned int nr = DRM_IOCTL_NR(cmd);
    	int retcode = -EINVAL;
    	char stack_kdata[128];
    	char *kdata = NULL;
    	unsigned int in_size, out_size, drv_size, ksize;
    	bool is_driver_ioctl;
    
    	dev = file_priv->minor->dev;
    
    	if (drm_device_is_unplugged(dev))
    		return -ENODEV;
    
    	is_driver_ioctl = nr >= DRM_COMMAND_BASE && nr < DRM_COMMAND_END;
    
    	if (is_driver_ioctl) {
    		/* driver ioctl */
    		if (nr - DRM_COMMAND_BASE >= dev->driver->num_ioctls)
    			goto err_i1;
    		ioctl = &dev->driver->ioctls[nr - DRM_COMMAND_BASE];
    	} else {
    		/* core ioctl */
    		if (nr >= DRM_CORE_IOCTL_COUNT)
    			goto err_i1;
    		ioctl = &drm_ioctls[nr];
    	}
    
    	drv_size = _IOC_SIZE(ioctl->cmd);
    	out_size = in_size = _IOC_SIZE(cmd);
    	if ((cmd & ioctl->cmd & IOC_IN) == 0)
    		in_size = 0;
    	if ((cmd & ioctl->cmd & IOC_OUT) == 0)
    		out_size = 0;
    	ksize = max(max(in_size, out_size), drv_size);
    
    	DRM_DEBUG("pid=%d, dev=0x%lx, auth=%d, %s\n",
    		  task_pid_nr(current),
    		  (long)old_encode_dev(file_priv->minor->kdev->devt),
    		  file_priv->authenticated, ioctl->name);
    
    	/* Do not trust userspace, use our own definition */
    	func = ioctl->func;
    
    	if (unlikely(!func)) {
    		DRM_DEBUG("no function\n");
    		retcode = -EINVAL;
    		goto err_i1;
    	}
    
    	retcode = drm_ioctl_permit(ioctl->flags, file_priv);
    	if (unlikely(retcode))
    		goto err_i1;
    
    	if (ksize <= sizeof(stack_kdata)) {
    		kdata = stack_kdata;
    	} else {
    		kdata = kmalloc(ksize, GFP_KERNEL);
    		if (!kdata) {
    			retcode = -ENOMEM;
    			goto err_i1;
    		}
    	}
    
    	if (copy_from_user(kdata, (void __user *)arg, in_size) != 0) {
    		retcode = -EFAULT;
    		goto err_i1;
    	}
    
    	if (ksize > in_size)
    		memset(kdata + in_size, 0, ksize - in_size);
    
    	/* Enforce sane locking for modern driver ioctls. Core ioctls are
    	 * too messy still. */
    	if ((!drm_core_check_feature(dev, DRIVER_LEGACY) && is_driver_ioctl) ||
    	    (ioctl->flags & DRM_UNLOCKED))
    		retcode = func(dev, kdata, file_priv);
    	else {
    		mutex_lock(&drm_global_mutex);
    		retcode = func(dev, kdata, file_priv);
    		mutex_unlock(&drm_global_mutex);
    	}
    
    	if (copy_to_user((void __user *)arg, kdata, out_size) != 0)
    		retcode = -EFAULT;
    
          err_i1:
    	if (!ioctl)
    		DRM_DEBUG("invalid ioctl: pid=%d, dev=0x%lx, auth=%d, cmd=0x%02x, nr=0x%02x\n",
    			  task_pid_nr(current),
    			  (long)old_encode_dev(file_priv->minor->kdev->devt),
    			  file_priv->authenticated, cmd, nr);
    
    	if (kdata != stack_kdata)
    		kfree(kdata);
    	if (retcode)
    		DRM_DEBUG("ret = %d\n", retcode);
    	return retcode;
    }
    EXPORT_SYMBOL(drm_ioctl);
    
    /**
     * drm_ioctl_flags - Check for core ioctl and return ioctl permission flags
     * @nr: ioctl number
     * @flags: where to return the ioctl permission flags
     *
     * This ioctl is only used by the vmwgfx driver to augment the access checks
     * done by the drm core and insofar a pretty decent layering violation. This
     * shouldn't be used by any drivers.
     *
     * Returns:
     * True if the @nr corresponds to a DRM core ioctl number, false otherwise.
     */
    bool drm_ioctl_flags(unsigned int nr, unsigned int *flags)
    {
    	if (nr >= DRM_COMMAND_BASE && nr < DRM_COMMAND_END)
    		return false;
    
    	if (nr >= DRM_CORE_IOCTL_COUNT)
    		return false;
    
    	*flags = drm_ioctls[nr].flags;
    	return true;
    }
    EXPORT_SYMBOL(drm_ioctl_flags);