drm: 32/64-bit DRM ioctl compatibility patch

The patch is against a 2.6.11 kernel tree.  I am running this with a
32-bit X server (compiled up from X.org CVS as of a couple of weeks
ago) and 32-bit DRI libraries and clients.  All the userland stuff is
identical to what I am using under a 32-bit kernel on my G4 powerbook
(which is a 32-bit machine of course).  I haven't tried compiling up a
64-bit X server or clients yet.

In the compatibility routines I have assumed that the kernel can
safely access user addresses after set_fs(KERNEL_DS).  That is, where
an ioctl argument structure contains pointers to other structures, and
those other structures are already compatible between the 32-bit and
64-bit ABIs (i.e. they only contain things like chars, shorts or
ints), I just check the address with access_ok() and then pass it
through to the 64-bit ioctl code.  I believe this approach may not
work on sparc64, but it does work on ppc64 and x86_64 at least.

One tricky area which may need to be revisited is the question of how
to handle the handles which we pass back to userspace to identify
mappings.  These handles are generated in the ADDMAP ioctl and then
passed in as the offset value to mmap.  However, offset values for
mmap seem to be generated in other ways as well, particularly for AGP
mappings.

The approach I have ended up with is to generate a fake 32-bit handle
only for _DRM_SHM mappings.  The handles for other mappings (AGP, REG,
FB) are physical addresses which are already limited to 32 bits, and
generating fake handles for them created all sorts of problems in the
mmap/nopage code.

This patch has been updated to use the new compatibility ioctls.

From: Paul Mackerras <paulus@samba.org>
Signed-off-by: Dave Airlie <airlied@linux.ie>

drivers/char/drm/Makefile

@@ -19,6 +19,11 @@ radeon-objs := radeon_drv.o radeon_cp.o radeon_state.o radeon_mem.o radeon_irq.o
 ffb-objs    := ffb_drv.o ffb_context.o
 sis-objs    := sis_drv.o sis_ds.o sis_mm.o
 
+ifeq ($(CONFIG_COMPAT),y)
+drm-objs    += drm_ioc32.o
+radeon-objs += radeon_ioc32.o
+endif
+
 obj-$(CONFIG_DRM)	+= drm.o
 obj-$(CONFIG_DRM_GAMMA) += gamma.o
 obj-$(CONFIG_DRM_TDFX)	+= tdfx.o

drivers/char/drm/drmP.h

@@ -316,6 +316,9 @@ do {									\
 typedef int drm_ioctl_t( struct inode *inode, struct file *filp,
 			 unsigned int cmd, unsigned long arg );
 
+typedef int drm_ioctl_compat_t(struct file *filp, unsigned int cmd,
+			       unsigned long arg);
+
 typedef struct drm_ioctl_desc {
 	drm_ioctl_t	     *func;
 	int		     auth_needed;
@@ -775,6 +778,8 @@ extern int           drm_version(struct inode *inode, struct file *filp,
 				  unsigned int cmd, unsigned long arg);
 extern int           drm_ioctl(struct inode *inode, struct file *filp,
 				unsigned int cmd, unsigned long arg);
+extern long	     drm_compat_ioctl(struct file *filp,
+				unsigned int cmd, unsigned long arg);
 extern int           drm_takedown(drm_device_t * dev);
 
 				/* Device support (drm_fops.h) */

drivers/char/drm/drm_bufs.c

@@ -60,6 +60,15 @@ int drm_order( unsigned long size )
 }
 EXPORT_SYMBOL(drm_order);
 
+#ifdef CONFIG_COMPAT
+/*
+ * Used to allocate 32-bit handles for _DRM_SHM regions
+ * The 0x10000000 value is chosen to be out of the way of
+ * FB/register and GART physical addresses.
+ */
+static unsigned int map32_handle = 0x10000000;
+#endif
+
 /**
  * Ioctl to specify a range of memory that is available for mapping by a non-root process.
  *
@@ -187,16 +196,18 @@ int drm_addmap( struct inode *inode, struct file *filp,
 
 	down(&dev->struct_sem);
 	list_add(&list->head, &dev->maplist->head);
+#ifdef CONFIG_COMPAT
+	/* Assign a 32-bit handle for _DRM_SHM mappings */
+	/* We do it here so that dev->struct_sem protects the increment */
+	if (map->type == _DRM_SHM)
+		map->offset = map32_handle += PAGE_SIZE;
+#endif
  	up(&dev->struct_sem);
 
 	if ( copy_to_user( argp, map, sizeof(*map) ) )
 		return -EFAULT;
-	if ( map->type != _DRM_SHM ) {
-		if ( copy_to_user( &argp->handle,
-				   &map->offset,
-				   sizeof(map->offset) ) )
+	if (copy_to_user(&argp->handle, &map->offset, sizeof(map->offset)))
 		return -EFAULT;
-	}
 	return 0;
 }
 
@@ -240,7 +251,7 @@ int drm_rmmap(struct inode *inode, struct file *filp,
 		r_list = list_entry(list, drm_map_list_t, head);
 
 		if(r_list->map &&
-		   r_list->map->handle == request.handle &&
+		   r_list->map->offset == (unsigned long) request.handle &&
 		   r_list->map->flags & _DRM_REMOVABLE) break;
 	}
 

drivers/char/drm/drm_context.c

@@ -225,7 +225,7 @@ int drm_getsareactx(struct inode *inode, struct file *filp,
 	map = dev->context_sareas[request.ctx_id];
 	up(&dev->struct_sem);
 
-	request.handle = map->handle;
+	request.handle = (void *) map->offset;
 	if (copy_to_user(argp, &request, sizeof(request)))
 		return -EFAULT;
 	return 0;
@@ -261,8 +261,8 @@ int drm_setsareactx(struct inode *inode, struct file *filp,
 	down(&dev->struct_sem);
 	list_for_each(list, &dev->maplist->head) {
 		r_list = list_entry(list, drm_map_list_t, head);
-		if(r_list->map &&
-		   r_list->map->handle == request.handle)
+		if (r_list->map
+		    && r_list->map->offset == (unsigned long) request.handle)
 			goto found;
 	}
 bad:

drivers/char/drm/drm_ioc32.c

+/**
+ * \file drm_ioc32.c
+ *
+ * 32-bit ioctl compatibility routines for the DRM.
+ *
+ * \author Paul Mackerras <paulus@samba.org>
+ *
+ * Copyright (C) Paul Mackerras 2005.
+ * All Rights Reserved.
+ *
+ * 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
+ * THE AUTHOR 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 <linux/compat.h>
+#include <linux/ioctl32.h>
+
+#include "drmP.h"
+#include "drm_core.h"
+
+#define DRM_IOCTL_VERSION32		DRM_IOWR(0x00, drm_version32_t)
+#define DRM_IOCTL_GET_UNIQUE32		DRM_IOWR(0x01, drm_unique32_t)
+#define DRM_IOCTL_GET_MAP32		DRM_IOWR(0x04, drm_map32_t)
+#define DRM_IOCTL_GET_CLIENT32		DRM_IOWR(0x05, drm_client32_t)
+#define DRM_IOCTL_GET_STATS32		DRM_IOR( 0x06, drm_stats32_t)
+
+#define DRM_IOCTL_SET_UNIQUE32		DRM_IOW( 0x10, drm_unique32_t)
+#define DRM_IOCTL_ADD_MAP32		DRM_IOWR(0x15, drm_map32_t)
+#define DRM_IOCTL_ADD_BUFS32		DRM_IOWR(0x16, drm_buf_desc32_t)
+#define DRM_IOCTL_MARK_BUFS32		DRM_IOW( 0x17, drm_buf_desc32_t)
+#define DRM_IOCTL_INFO_BUFS32		DRM_IOWR(0x18, drm_buf_info32_t)
+#define DRM_IOCTL_MAP_BUFS32		DRM_IOWR(0x19, drm_buf_map32_t)
+#define DRM_IOCTL_FREE_BUFS32		DRM_IOW( 0x1a, drm_buf_free32_t)
+
+#define DRM_IOCTL_RM_MAP32		DRM_IOW( 0x1b, drm_map32_t)
+
+#define DRM_IOCTL_SET_SAREA_CTX32	DRM_IOW( 0x1c, drm_ctx_priv_map32_t)
+#define DRM_IOCTL_GET_SAREA_CTX32	DRM_IOWR(0x1d, drm_ctx_priv_map32_t)
+
+#define DRM_IOCTL_RES_CTX32		DRM_IOWR(0x26, drm_ctx_res32_t)
+#define DRM_IOCTL_DMA32			DRM_IOWR(0x29, drm_dma32_t)
+
+#define DRM_IOCTL_AGP_ENABLE32		DRM_IOW( 0x32, drm_agp_mode32_t)
+#define DRM_IOCTL_AGP_INFO32		DRM_IOR( 0x33, drm_agp_info32_t)
+#define DRM_IOCTL_AGP_ALLOC32		DRM_IOWR(0x34, drm_agp_buffer32_t)
+#define DRM_IOCTL_AGP_FREE32		DRM_IOW( 0x35, drm_agp_buffer32_t)
+#define DRM_IOCTL_AGP_BIND32		DRM_IOW( 0x36, drm_agp_binding32_t)
+#define DRM_IOCTL_AGP_UNBIND32		DRM_IOW( 0x37, drm_agp_binding32_t)
+
+#define DRM_IOCTL_SG_ALLOC32		DRM_IOW( 0x38, drm_scatter_gather32_t)
+#define DRM_IOCTL_SG_FREE32		DRM_IOW( 0x39, drm_scatter_gather32_t)
+
+#define DRM_IOCTL_WAIT_VBLANK32		DRM_IOWR(0x3a, drm_wait_vblank32_t)
+
+typedef struct drm_version_32 {
+	int	version_major;	  /**< Major version */
+	int	version_minor;	  /**< Minor version */
+	int	version_patchlevel;/**< Patch level */
+	u32	name_len;	  /**< Length of name buffer */
+	u32	name;		  /**< Name of driver */
+	u32	date_len;	  /**< Length of date buffer */
+	u32	date;		  /**< User-space buffer to hold date */
+	u32	desc_len;	  /**< Length of desc buffer */
+	u32	desc;		  /**< User-space buffer to hold desc */
+} drm_version32_t;
+
+static int compat_drm_version(struct file *file, unsigned int cmd,
+			      unsigned long arg)
+{
+	drm_version32_t v32;
+	drm_version_t __user *version;
+	int err;
+
+	if (copy_from_user(&v32, (void __user *) arg, sizeof(v32)))
+		return -EFAULT;
+
+	version = compat_alloc_user_space(sizeof(*version));
+	if (!access_ok(VERIFY_WRITE, version, sizeof(*version)))
+		return -EFAULT;
+	if (__put_user(v32.name_len, &version->name_len)
+	    || __put_user((void __user *)(unsigned long)v32.name,
+			  &version->name)
+	    || __put_user(v32.date_len, &version->date_len)
+	    || __put_user((void __user *)(unsigned long)v32.date,
+			  &version->date)
+	    || __put_user(v32.desc_len, &version->desc_len)
+	    || __put_user((void __user *)(unsigned long)v32.desc,
+			  &version->desc))
+		return -EFAULT;
+
+	err = drm_ioctl(file->f_dentry->d_inode, file,
+			DRM_IOCTL_VERSION, (unsigned long) version);
+	if (err)
+		return err;
+
+	if (__get_user(v32.version_major, &version->version_major)
+	    || __get_user(v32.version_minor, &version->version_minor)
+	    || __get_user(v32.version_patchlevel, &version->version_patchlevel)
+	    || __get_user(v32.name_len, &version->name_len)
+	    || __get_user(v32.date_len, &version->date_len)
+	    || __get_user(v32.desc_len, &version->desc_len))
+		return -EFAULT;
+
+	if (copy_to_user((void __user *) arg, &v32, sizeof(v32)))
+		return -EFAULT;
+	return 0;
+}
+
+typedef struct drm_unique32 {
+	u32 unique_len;	/**< Length of unique */
+	u32 unique;	/**< Unique name for driver instantiation */
+} drm_unique32_t;
+
+static int compat_drm_getunique(struct file *file, unsigned int cmd,
+				unsigned long arg)
+{
+	drm_unique32_t uq32;
+	drm_unique_t __user *u;
+	int err;
+
+	if (copy_from_user(&uq32, (void __user *) arg, sizeof(uq32)))
+		return -EFAULT;
+
+	u = compat_alloc_user_space(sizeof(*u));
+	if (!access_ok(VERIFY_WRITE, u, sizeof(*u)))
+		return -EFAULT;
+	if (__put_user(uq32.unique_len, &u->unique_len)
+	    || __put_user((void __user *)(unsigned long) uq32.unique,
+			  &u->unique))
+		return -EFAULT;
+
+	err = drm_ioctl(file->f_dentry->d_inode, file,
+			DRM_IOCTL_GET_UNIQUE, (unsigned long) u);
+	if (err)
+		return err;
+
+	if (__get_user(uq32.unique_len, &u->unique_len))
+		return -EFAULT;
+	if (copy_to_user((void __user *) arg, &uq32, sizeof(uq32)))
+		return -EFAULT;
+	return 0;
+}
+
+static int compat_drm_setunique(struct file *file, unsigned int cmd,
+				unsigned long arg)
+{
+	drm_unique32_t uq32;
+	drm_unique_t __user *u;
+
+	if (copy_from_user(&uq32, (void __user *) arg, sizeof(uq32)))
+		return -EFAULT;
+
+	u = compat_alloc_user_space(sizeof(*u));
+	if (!access_ok(VERIFY_WRITE, u, sizeof(*u)))
+		return -EFAULT;
+	if (__put_user(uq32.unique_len, &u->unique_len)
+	    || __put_user((void __user *)(unsigned long) uq32.unique,
+			  &u->unique))
+		return -EFAULT;
+
+	return drm_ioctl(file->f_dentry->d_inode, file,
+			 DRM_IOCTL_SET_UNIQUE, (unsigned long) u);
+}
+
+typedef struct drm_map32 {
+	u32	offset;	 	/**< Requested physical address (0 for SAREA)*/
+	u32	size;	 	/**< Requested physical size (bytes) */
+	drm_map_type_t	type;	/**< Type of memory to map */
+	drm_map_flags_t flags;	/**< Flags */
+	u32	handle;		/**< User-space: "Handle" to pass to mmap() */
+	int	mtrr;		/**< MTRR slot used */
+} drm_map32_t;
+
+static int compat_drm_getmap(struct file *file, unsigned int cmd,
+			     unsigned long arg)
+{
+	drm_map32_t __user *argp = (void __user *)arg;
+	drm_map32_t m32;
+	drm_map_t __user *map;
+	int idx, err;
+	void *handle;
+
+	if (get_user(idx, &argp->offset))
+		return -EFAULT;
+
+	map = compat_alloc_user_space(sizeof(*map));
+	if (!access_ok(VERIFY_WRITE, map, sizeof(*map)))
+		return -EFAULT;
+	if (__put_user(idx, &map->offset))
+		return -EFAULT;
+
+	err = drm_ioctl(file->f_dentry->d_inode, file,
+			DRM_IOCTL_GET_MAP, (unsigned long) map);
+	if (err)
+		return err;
+
+	if (__get_user(m32.offset, &map->offset)
+	    || __get_user(m32.size, &map->size)
+	    || __get_user(m32.type, &map->type)
+	    || __get_user(m32.flags, &map->flags)
+	    || __get_user(handle, &map->handle)
+	    || __get_user(m32.mtrr, &map->mtrr))
+		return -EFAULT;
+
+	m32.handle = (unsigned long) handle;
+	if (copy_to_user(argp, &m32, sizeof(m32)))
+		return -EFAULT;
+	return 0;
+
+}
+
+static int compat_drm_addmap(struct file *file, unsigned int cmd,
+			     unsigned long arg)
+{
+	drm_map32_t __user *argp = (void __user *)arg;
+	drm_map32_t m32;
+	drm_map_t __user *map;
+	int err;
+	void *handle;
+
+	if (copy_from_user(&m32, argp, sizeof(m32)))
+		return -EFAULT;
+
+	map = compat_alloc_user_space(sizeof(*map));
+	if (!access_ok(VERIFY_WRITE, map, sizeof(*map)))
+		return -EFAULT;
+	if (__put_user(m32.offset, &map->offset)
+	    || __put_user(m32.size, &map->size)
+	    || __put_user(m32.type, &map->type)
+	    || __put_user(m32.flags, &map->flags))
+		return -EFAULT;
+
+	err = drm_ioctl(file->f_dentry->d_inode, file,
+			DRM_IOCTL_ADD_MAP, (unsigned long) map);
+	if (err)
+		return err;
+
+	if (__get_user(m32.offset, &map->offset)
+	    || __get_user(m32.mtrr, &map->mtrr)
+	    || __get_user(handle, &map->handle))
+		return -EFAULT;
+
+	m32.handle = (unsigned long) handle;
+	if (m32.handle != (unsigned long) handle && printk_ratelimit())
+		printk(KERN_ERR "compat_drm_addmap truncated handle"
+		       " %p for type %d offset %x\n",
+		       handle, m32.type, m32.offset);
+
+	if (copy_to_user(argp, &m32, sizeof(m32)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int compat_drm_rmmap(struct file *file, unsigned int cmd,
+			    unsigned long arg)
+{
+	drm_map32_t __user *argp = (void __user *)arg;
+	drm_map_t __user *map;
+	u32 handle;
+
+	if (get_user(handle, &argp->handle))
+		return -EFAULT;
+
+	map = compat_alloc_user_space(sizeof(*map));
+	if (!access_ok(VERIFY_WRITE, map, sizeof(*map)))
+		return -EFAULT;
+	if (__put_user((void *)(unsigned long) handle, &map->handle))
+		return -EFAULT;
+
+	return drm_ioctl(file->f_dentry->d_inode, file,
+			 DRM_IOCTL_RM_MAP, (unsigned long) map);
+}
+
+typedef struct drm_client32 {
+	int	idx;	/**< Which client desired? */
+	int	auth;	/**< Is client authenticated? */
+	u32	pid;	/**< Process ID */
+	u32	uid;	/**< User ID */
+	u32	magic;	/**< Magic */
+	u32	iocs;	/**< Ioctl count */
+} drm_client32_t;
+
+static int compat_drm_getclient(struct file *file, unsigned int cmd,
+				unsigned long arg)
+{
+	drm_client32_t c32;
+	drm_client32_t __user *argp = (void __user *)arg;
+	drm_client_t __user *client;
+	int idx, err;
+
+	if (get_user(idx, &argp->idx))
+		return -EFAULT;
+
+	client = compat_alloc_user_space(sizeof(*client));
+	if (!access_ok(VERIFY_WRITE, client, sizeof(*client)))
+		return -EFAULT;
+	if (__put_user(idx, &client->idx))
+		return -EFAULT;
+
+	err = drm_ioctl(file->f_dentry->d_inode, file,
+			DRM_IOCTL_GET_CLIENT, (unsigned long) client);
+	if (err)
+		return err;
+
+	if (__get_user(c32.auth, &client->auth)
+	    || __get_user(c32.pid, &client->pid)
+	    || __get_user(c32.uid, &client->uid)
+	    || __get_user(c32.magic, &client->magic)
+	    || __get_user(c32.iocs, &client->iocs))
+		return -EFAULT;
+
+	if (copy_to_user(argp, &c32, sizeof(c32)))
+		return -EFAULT;
+	return 0;
+}
+
+typedef struct drm_stats32 {
+	u32 count;
+	struct {
+		u32 value;
+		drm_stat_type_t type;
+	} data[15];
+} drm_stats32_t;
+
+static int compat_drm_getstats(struct file *file, unsigned int cmd,
+			       unsigned long arg)
+{
+	drm_stats32_t s32;
+	drm_stats32_t __user *argp = (void __user *)arg;
+	drm_stats_t __user *stats;
+	int i, err;
+
+	stats = compat_alloc_user_space(sizeof(*stats));
+	if (!access_ok(VERIFY_WRITE, stats, sizeof(*stats)))
+		return -EFAULT;
+
+	err = drm_ioctl(file->f_dentry->d_inode, file,
+			DRM_IOCTL_GET_STATS, (unsigned long) stats);
+	if (err)
+		return err;
+
+	if (__get_user(s32.count, &stats->count))
+		return -EFAULT;
+	for (i = 0; i < 15; ++i)
+		if (__get_user(s32.data[i].value, &stats->data[i].value)
+		    || __get_user(s32.data[i].type, &stats->data[i].type))
+			return -EFAULT;
+
+	if (copy_to_user(argp, &s32, sizeof(s32)))
+		return -EFAULT;
+	return 0;
+}
+
+typedef struct drm_buf_desc32 {
+	int	      count;	 /**< Number of buffers of this size */
+	int	      size;	 /**< Size in bytes */
+	int	      low_mark;	 /**< Low water mark */
+	int	      high_mark; /**< High water mark */
+	int	      flags;
+	u32	      agp_start; /**< Start address in the AGP aperture */
+} drm_buf_desc32_t;
+
+static int compat_drm_addbufs(struct file *file, unsigned int cmd,
+			      unsigned long arg)
+{
+	drm_buf_desc32_t __user *argp = (void __user *)arg;
+	drm_buf_desc_t __user *buf;
+	int err;
+	unsigned long agp_start;
+
+	buf = compat_alloc_user_space(sizeof(*buf));
+	if (!access_ok(VERIFY_WRITE, buf, sizeof(*buf))
+	    || !access_ok(VERIFY_WRITE, argp, sizeof(*argp)))
+		return -EFAULT;
+
+	if (__copy_in_user(buf, argp, offsetof(drm_buf_desc32_t, agp_start))
+	    || __get_user(agp_start, &argp->agp_start)
+	    || __put_user(agp_start, &buf->agp_start))
+		return -EFAULT;
+
+	err = drm_ioctl(file->f_dentry->d_inode, file,
+			DRM_IOCTL_ADD_BUFS, (unsigned long) buf);
+	if (err)
+		return err;
+
+	if (__copy_in_user(argp, buf, offsetof(drm_buf_desc32_t, agp_start))
+	    || __get_user(agp_start, &buf->agp_start)
+	    || __put_user(agp_start, &argp->agp_start))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int compat_drm_markbufs(struct file *file, unsigned int cmd,
+			       unsigned long arg)
+{
+	drm_buf_desc32_t b32;
+	drm_buf_desc32_t __user *argp = (void __user *)arg;
+	drm_buf_desc_t __user *buf;
+
+	if (copy_from_user(&b32, argp, sizeof(b32)))
+		return -EFAULT;
+
+	buf = compat_alloc_user_space(sizeof(*buf));
+	if (!access_ok(VERIFY_WRITE, buf, sizeof(*buf)))
+		return -EFAULT;
+
+	if (__put_user(b32.size, &buf->size)
+	    || __put_user(b32.low_mark, &buf->low_mark)
+	    || __put_user(b32.high_mark, &buf->high_mark))
+		return -EFAULT;
+
+	return drm_ioctl(file->f_dentry->d_inode, file,
+			 DRM_IOCTL_MARK_BUFS, (unsigned long) buf);
+}
+
+typedef struct drm_buf_info32 {
+	int	       count;	/**< Entries in list */
+	u32	       list;
+} drm_buf_info32_t;
+
+static int compat_drm_infobufs(struct file *file, unsigned int cmd,
+			       unsigned long arg)
+{
+	drm_buf_info32_t req32;
+	drm_buf_info32_t __user *argp = (void __user *)arg;
+	drm_buf_desc32_t __user *to;
+	drm_buf_info_t __user *request;
+	drm_buf_desc_t __user *list;
+	size_t nbytes;
+	int i, err;
+	int count, actual;
+
+	if (copy_from_user(&req32, argp, sizeof(req32)))
+		return -EFAULT;
+
+	count = req32.count;
+	to = (drm_buf_desc32_t __user *)(unsigned long) req32.list;
+	if (count < 0)
+		count = 0;
+	if (count > 0
+	    && !access_ok(VERIFY_WRITE, to, count * sizeof(drm_buf_desc32_t)))
+		return -EFAULT;
+
+	nbytes = sizeof(*request) + count * sizeof(drm_buf_desc_t);
+	request = compat_alloc_user_space(nbytes);
+	if (!access_ok(VERIFY_WRITE, request, nbytes))
+		return -EFAULT;
+	list = (drm_buf_desc_t *) (request + 1);
+
+	if (__put_user(count, &request->count)
+	    || __put_user(list, &request->list))
+		return -EFAULT;
+
+	err = drm_ioctl(file->f_dentry->d_inode, file,
+			DRM_IOCTL_INFO_BUFS, (unsigned long) request);
+	if (err)
+		return err;
+
+	if (__get_user(actual, &request->count))
+		return -EFAULT;
+	if (count >= actual)
+		for (i = 0; i < actual; ++i)
+			if (__copy_in_user(&to[i], &list[i],
+					   offsetof(drm_buf_desc_t, flags)))
+				return -EFAULT;
+
+	if (__put_user(actual, &argp->count))
+		return -EFAULT;
+
+	return 0;
+}
+
+typedef struct drm_buf_pub32 {
+	int	idx;		/**< Index into the master buffer list */
+	int	total;		/**< Buffer size */
+	int	used;		/**< Amount of buffer in use (for DMA) */
+	u32	address;	/**< Address of buffer */
+} drm_buf_pub32_t;
+
+typedef struct drm_buf_map32 {
+	int	count;		/**< Length of the buffer list */
+	u32	virtual;	/**< Mmap'd area in user-virtual */
+	u32	list;		/**< Buffer information */
+} drm_buf_map32_t;
+
+static int compat_drm_mapbufs(struct file *file, unsigned int cmd,
+			      unsigned long arg)
+{
+	drm_buf_map32_t __user *argp = (void __user *)arg;
+	drm_buf_map32_t req32;
+	drm_buf_pub32_t __user *list32;
+	drm_buf_map_t __user *request;
+	drm_buf_pub_t __user *list;
+	int i, err;
+	int count, actual;
+	size_t nbytes;
+	void __user *addr;
+
+	if (copy_from_user(&req32, argp, sizeof(req32)))
+		return -EFAULT;
+	count = req32.count;
+	list32 = (void __user *)(unsigned long)req32.list;
+
+	if (count < 0)
+		return -EINVAL;
+	nbytes = sizeof(*request) + count * sizeof(drm_buf_pub_t);
+	request = compat_alloc_user_space(nbytes);
+	if (!access_ok(VERIFY_WRITE, request, nbytes))
+		return -EFAULT;
+	list = (drm_buf_pub_t *) (request + 1);
+
+	if (__put_user(count, &request->count)
+	    || __put_user(list, &request->list))
+		return -EFAULT;
+
+	err = drm_ioctl(file->f_dentry->d_inode, file,
+			DRM_IOCTL_MAP_BUFS, (unsigned long) request);
+	if (err)
+		return err;
+
+	if (__get_user(actual, &request->count))
+		return -EFAULT;
+	if (count >= actual)
+		for (i = 0; i < actual; ++i)
+			if (__copy_in_user(&list32[i], &list[i],
+					   offsetof(drm_buf_pub_t, address))
+			    || __get_user(addr, &list[i].address)
+			    || __put_user((unsigned long) addr,
+					  &list32[i].address))
+				return -EFAULT;
+
+	if (__put_user(actual, &argp->count)
+	    || __get_user(addr, &request->virtual)
+	    || __put_user((unsigned long) addr, &argp->virtual))
+		return -EFAULT;
+
+	return 0;
+}
+
+typedef struct drm_buf_free32 {
+	int	count;
+	u32	list;
+} drm_buf_free32_t;
+
+static int compat_drm_freebufs(struct file *file, unsigned int cmd,
+			       unsigned long arg)
+{
+	drm_buf_free32_t req32;
+	drm_buf_free_t __user *request;
+	drm_buf_free32_t __user *argp = (void __user *)arg;
+
+	if (copy_from_user(&req32, argp, sizeof(req32)))
+		return -EFAULT;
+
+	request = compat_alloc_user_space(sizeof(*request));
+	if (!access_ok(VERIFY_WRITE, request, sizeof(*request)))
+		return -EFAULT;
+	if (__put_user(req32.count, &request->count)
+	    || __put_user((int __user *)(unsigned long) req32.list,
+			  &request->list))
+		return -EFAULT;
+
+	return drm_ioctl(file->f_dentry->d_inode, file,
+			 DRM_IOCTL_FREE_BUFS, (unsigned long) request);
+}
+
+typedef struct drm_ctx_priv_map32 {
+	unsigned int	ctx_id;  /**< Context requesting private mapping */
+	u32		handle; /**< Handle of map */
+} drm_ctx_priv_map32_t;
+
+static int compat_drm_setsareactx(struct file *file, unsigned int cmd,
+				  unsigned long arg)
+{
+	drm_ctx_priv_map32_t req32;
+	drm_ctx_priv_map_t __user *request;
+	drm_ctx_priv_map32_t __user *argp = (void __user *)arg;
+
+	if (copy_from_user(&req32, argp, sizeof(req32)))
+		return -EFAULT;
+
+	request = compat_alloc_user_space(sizeof(*request));
+	if (!access_ok(VERIFY_WRITE, request, sizeof(*request)))
+		return -EFAULT;
+	if (__put_user(req32.ctx_id, &request->ctx_id)
+	    || __put_user((void *)(unsigned long) req32.handle,
+			  &request->handle))
+		return -EFAULT;
+
+	return drm_ioctl(file->f_dentry->d_inode, file,
+			 DRM_IOCTL_SET_SAREA_CTX, (unsigned long) request);
+}
+
+static int compat_drm_getsareactx(struct file *file, unsigned int cmd,
+				  unsigned long arg)
+{
+	drm_ctx_priv_map_t __user *request;
+	drm_ctx_priv_map32_t __user *argp = (void __user *)arg;
+	int err;
+	unsigned int ctx_id;
+	void *handle;
+
+	if (!access_ok(VERIFY_WRITE, argp, sizeof(*argp))
+	    || __get_user(ctx_id, &argp->ctx_id))
+		return -EFAULT;
+
+	request = compat_alloc_user_space(sizeof(*request));
+	if (!access_ok(VERIFY_WRITE, request, sizeof(*request)))
+		return -EFAULT;
+	if (__put_user(ctx_id, &request->ctx_id))
+		return -EFAULT;
+
+	err = drm_ioctl(file->f_dentry->d_inode, file,
+			DRM_IOCTL_GET_SAREA_CTX, (unsigned long) request);
+	if (err)
+		return err;
+
+	if (__get_user(handle, &request->handle)
+	    || __put_user((unsigned long) handle, &argp->handle))
+		return -EFAULT;
+
+	return 0;
+}
+
+typedef struct drm_ctx_res32 {
+	int	count;
+	u32	contexts;
+} drm_ctx_res32_t;
+
+static int compat_drm_resctx(struct file *file, unsigned int cmd,
+			     unsigned long arg)
+{
+	drm_ctx_res32_t __user *argp = (void __user *)arg;
+	drm_ctx_res32_t res32;
+	drm_ctx_res_t __user *res;
+	int err;
+
+	if (copy_from_user(&res32, argp, sizeof(res32)))
+		return -EFAULT;
+
+	res = compat_alloc_user_space(sizeof(*res));
+	if (!access_ok(VERIFY_WRITE, res, sizeof(*res)))
+		return -EFAULT;
+	if (__put_user(res32.count, &res->count)
+	    || __put_user((drm_ctx_t __user *)(unsigned long) res32.contexts,
+			  &res->contexts))
+		return -EFAULT;
+
+	err = drm_ioctl(file->f_dentry->d_inode, file,
+			DRM_IOCTL_RES_CTX, (unsigned long) res);
+	if (err)
+		return err;
+
+	if (__get_user(res32.count, &res->count)
+	    || __put_user(res32.count, &argp->count))
+		return -EFAULT;
+
+	return 0;
+}
+
+typedef struct drm_dma32 {
+	int	context;	  /**< Context handle */
+	int	send_count;	  /**< Number of buffers to send */
+	u32	send_indices;	  /**< List of handles to buffers */
+	u32	send_sizes;	  /**< Lengths of data to send */
+	drm_dma_flags_t flags;		  /**< Flags */
+	int	request_count;	  /**< Number of buffers requested */
+	int	request_size;	  /**< Desired size for buffers */
+	u32	request_indices;  /**< Buffer information */
+	u32	request_sizes;
+	int	granted_count;	  /**< Number of buffers granted */
+} drm_dma32_t;
+
+static int compat_drm_dma(struct file *file, unsigned int cmd,
+			  unsigned long arg)
+{
+	drm_dma32_t d32;
+	drm_dma32_t __user *argp = (void __user *) arg;
+	drm_dma_t __user *d;
+	int err;
+
+	if (copy_from_user(&d32, argp, sizeof(d32)))
+		return -EFAULT;
+
+	d = compat_alloc_user_space(sizeof(*d));
+	if (!access_ok(VERIFY_WRITE, d, sizeof(*d)))
+		return -EFAULT;
+
+	if (__put_user(d32.context, &d->context)
+	    || __put_user(d32.send_count, &d->send_count)
+	    || __put_user((int __user *)(unsigned long) d32.send_indices,
+			  &d->send_indices)
+	    || __put_user((int __user *)(unsigned long) d32.send_sizes,
+			  &d->send_sizes)
+	    || __put_user(d32.flags, &d->flags)
+	    || __put_user(d32.request_count, &d->request_count)
+	    || __put_user((int __user *)(unsigned long) d32.request_indices,
+			  &d->request_indices)
+	    || __put_user((int __user *)(unsigned long) d32.request_sizes,
+			  &d->request_sizes))
+		return -EFAULT;
+
+	err = drm_ioctl(file->f_dentry->d_inode, file,
+			DRM_IOCTL_DMA, (unsigned long) d);
+	if (err)
+		return err;
+
+	if (__get_user(d32.request_size, &d->request_size)
+	    || __get_user(d32.granted_count, &d->granted_count)
+	    || __put_user(d32.request_size, &argp->request_size)
+	    || __put_user(d32.granted_count, &argp->granted_count))
+		return -EFAULT;
+
+	return 0;
+}
+
+#if __OS_HAS_AGP
+typedef struct drm_agp_mode32 {
+	u32 mode;	/**< AGP mode */
+} drm_agp_mode32_t;
+
+static int compat_drm_agp_enable(struct file *file, unsigned int cmd,
+				 unsigned long arg)
+{
+	drm_agp_mode32_t __user *argp = (void __user *)arg;
+	drm_agp_mode32_t m32;
+	drm_agp_mode_t __user *mode;
+
+	if (get_user(m32.mode, &argp->mode))
+		return -EFAULT;
+
+	mode = compat_alloc_user_space(sizeof(*mode));
+	if (put_user(m32.mode, &mode->mode))
+		return -EFAULT;
+
+	return drm_ioctl(file->f_dentry->d_inode, file,
+			 DRM_IOCTL_AGP_ENABLE, (unsigned long) mode);
+}
+
+typedef struct drm_agp_info32 {
+	int       agp_version_major;
+	int       agp_version_minor;
+	u32	  mode;
+	u32	  aperture_base;  /* physical address */
+	u32	  aperture_size;  /* bytes */
+	u32	  memory_allowed; /* bytes */
+	u32	  memory_used;
+
+				/* PCI information */
+	unsigned short id_vendor;
+	unsigned short id_device;
+} drm_agp_info32_t;
+
+static int compat_drm_agp_info(struct file *file, unsigned int cmd,
+			       unsigned long arg)
+{
+	drm_agp_info32_t __user *argp = (void __user *)arg;
+	drm_agp_info32_t i32;
+	drm_agp_info_t __user *info;
+	int err;
+
+	info = compat_alloc_user_space(sizeof(*info));
+	if (!access_ok(VERIFY_WRITE, info, sizeof(*info)))
+		return -EFAULT;
+
+	err = drm_ioctl(file->f_dentry->d_inode, file,
+			DRM_IOCTL_AGP_INFO, (unsigned long) info);
+	if (err)
+		return err;
+
+	if (__get_user(i32.agp_version_major, &info->agp_version_major)
+	    || __get_user(i32.agp_version_minor, &info->agp_version_minor)
+	    || __get_user(i32.mode, &info->mode)
+	    || __get_user(i32.aperture_base, &info->aperture_base)
+	    || __get_user(i32.aperture_size, &info->aperture_size)
+	    || __get_user(i32.memory_allowed, &info->memory_allowed)
+	    || __get_user(i32.memory_used, &info->memory_used)
+	    || __get_user(i32.id_vendor, &info->id_vendor)
+	    || __get_user(i32.id_device, &info->id_device))
+		return -EFAULT;
+
+	if (copy_to_user(argp, &i32, sizeof(i32)))
+		return -EFAULT;
+
+	return 0;
+}
+
+typedef struct drm_agp_buffer32 {
+	u32 size;	/**< In bytes -- will round to page boundary */
+	u32 handle;	/**< Used for binding / unbinding */
+	u32 type;	/**< Type of memory to allocate */
+        u32 physical;	/**< Physical used by i810 */
+} drm_agp_buffer32_t;
+
+static int compat_drm_agp_alloc(struct file *file, unsigned int cmd,
+				unsigned long arg)
+{
+	drm_agp_buffer32_t __user *argp = (void __user *)arg;
+	drm_agp_buffer32_t req32;
+	drm_agp_buffer_t __user *request;
+	int err;
+
+	if (copy_from_user(&req32, argp, sizeof(req32)))
+		return -EFAULT;
+
+	request = compat_alloc_user_space(sizeof(*request));
+	if (!access_ok(VERIFY_WRITE, request, sizeof(*request))
+	    || __put_user(req32.size, &request->size)
+	    || __put_user(req32.type, &request->type))
+		return -EFAULT;
+
+	err = drm_ioctl(file->f_dentry->d_inode, file,
+			DRM_IOCTL_AGP_ALLOC, (unsigned long) request);
+	if (err)
+		return err;
+
+	if (__get_user(req32.handle, &request->handle)
+	    || __get_user(req32.physical, &request->physical)
+	    || copy_to_user(argp, &req32, sizeof(req32))) {
+		drm_ioctl(file->f_dentry->d_inode, file,
+			  DRM_IOCTL_AGP_FREE, (unsigned long) request);
+		return -EFAULT;
+	}
+
+	return 0;
+}
+
+static int compat_drm_agp_free(struct file *file, unsigned int cmd,
+			       unsigned long arg)
+{
+	drm_agp_buffer32_t __user *argp = (void __user *)arg;
+	drm_agp_buffer_t __user *request;
+	u32 handle;
+
+	request = compat_alloc_user_space(sizeof(*request));
+	if (!access_ok(VERIFY_WRITE, request, sizeof(*request))
+	    || get_user(handle, &argp->handle)
+	    || __put_user(handle, &request->handle))
+		return -EFAULT;
+
+	return drm_ioctl(file->f_dentry->d_inode, file,
+			 DRM_IOCTL_AGP_FREE, (unsigned long) request);
+}
+
+typedef struct drm_agp_binding32 {
+	u32 handle;	/**< From drm_agp_buffer */
+	u32 offset;	/**< In bytes -- will round to page boundary */
+} drm_agp_binding32_t;
+
+static int compat_drm_agp_bind(struct file *file, unsigned int cmd,
+			       unsigned long arg)
+{
+	drm_agp_binding32_t __user *argp = (void __user *)arg;
+	drm_agp_binding32_t req32;
+	drm_agp_binding_t __user *request;
+
+	if (copy_from_user(&req32, argp, sizeof(req32)))
+		return -EFAULT;
+
+	request = compat_alloc_user_space(sizeof(*request));
+	if (!access_ok(VERIFY_WRITE, request, sizeof(*request))
+	    || __put_user(req32.handle, &request->handle)
+	    || __put_user(req32.offset, &request->offset))
+		return -EFAULT;
+
+	return drm_ioctl(file->f_dentry->d_inode, file,
+			 DRM_IOCTL_AGP_BIND, (unsigned long) request);
+}
+
+static int compat_drm_agp_unbind(struct file *file, unsigned int cmd,
+				 unsigned long arg)
+{
+	drm_agp_binding32_t __user *argp = (void __user *)arg;
+	drm_agp_binding_t __user *request;
+	u32 handle;
+
+	request = compat_alloc_user_space(sizeof(*request));
+	if (!access_ok(VERIFY_WRITE, request, sizeof(*request))
+	    || get_user(handle, &argp->handle)
+	    || __put_user(handle, &request->handle))
+		return -EFAULT;
+
+	return drm_ioctl(file->f_dentry->d_inode, file,
+			 DRM_IOCTL_AGP_UNBIND, (unsigned long) request);
+}
+#endif /* __OS_HAS_AGP */
+
+typedef struct drm_scatter_gather32 {
+	u32 size;	/**< In bytes -- will round to page boundary */
+	u32 handle;	/**< Used for mapping / unmapping */
+} drm_scatter_gather32_t;
+
+static int compat_drm_sg_alloc(struct file *file, unsigned int cmd,
+			       unsigned long arg)
+{
+	drm_scatter_gather32_t __user *argp = (void __user *)arg;
+	drm_scatter_gather_t __user *request;
+	int err;
+	unsigned long x;
+
+	request = compat_alloc_user_space(sizeof(*request));
+	if (!access_ok(VERIFY_WRITE, request, sizeof(*request))
+	    || !access_ok(VERIFY_WRITE, argp, sizeof(*argp))
+	    || __get_user(x, &argp->size)
+	    || __put_user(x, &request->size))
+		return -EFAULT;
+
+	err = drm_ioctl(file->f_dentry->d_inode, file,
+			DRM_IOCTL_SG_ALLOC, (unsigned long) request);
+	if (err)
+		return err;
+
+	/* XXX not sure about the handle conversion here... */
+	if (__get_user(x, &request->handle)
+	    || __put_user(x >> PAGE_SHIFT, &argp->handle))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int compat_drm_sg_free(struct file *file, unsigned int cmd,
+			      unsigned long arg)
+{
+	drm_scatter_gather32_t __user *argp = (void __user *)arg;
+	drm_scatter_gather_t __user *request;
+	unsigned long x;
+
+	request = compat_alloc_user_space(sizeof(*request));
+	if (!access_ok(VERIFY_WRITE, request, sizeof(*request))
+	    || !access_ok(VERIFY_WRITE, argp, sizeof(*argp))
+	    || __get_user(x, &argp->handle)
+	    || __put_user(x << PAGE_SHIFT, &request->handle))
+		return -EFAULT;
+
+	return drm_ioctl(file->f_dentry->d_inode, file,
+			 DRM_IOCTL_SG_FREE, (unsigned long) request);
+}
+
+struct drm_wait_vblank_request32 {
+	drm_vblank_seq_type_t type;
+	unsigned int sequence;
+	u32 signal;
+};
+
+struct drm_wait_vblank_reply32 {
+	drm_vblank_seq_type_t type;
+	unsigned int sequence;
+	s32 tval_sec;
+	s32 tval_usec;
+};
+
+typedef union drm_wait_vblank32 {
+	struct drm_wait_vblank_request32 request;
+	struct drm_wait_vblank_reply32 reply;
+} drm_wait_vblank32_t;
+
+static int compat_drm_wait_vblank(struct file *file, unsigned int cmd,
+				  unsigned long arg)
+{
+	drm_wait_vblank32_t __user *argp = (void __user *)arg;
+	drm_wait_vblank32_t req32;
+	drm_wait_vblank_t __user *request;
+	int err;
+
+	if (copy_from_user(&req32, argp, sizeof(req32)))
+		return -EFAULT;
+
+	request = compat_alloc_user_space(sizeof(*request));
+	if (!access_ok(VERIFY_WRITE, request, sizeof(*request))
+	    || __put_user(req32.request.type, &request->request.type)
+	    || __put_user(req32.request.sequence, &request->request.sequence)
+	    || __put_user(req32.request.signal, &request->request.signal))
+		return -EFAULT;
+
+	err = drm_ioctl(file->f_dentry->d_inode, file,
+			DRM_IOCTL_WAIT_VBLANK, (unsigned long) request);
+	if (err)
+		return err;
+
+	if (__get_user(req32.reply.type, &request->reply.type)
+	    || __get_user(req32.reply.sequence, &request->reply.sequence)
+	    || __get_user(req32.reply.tval_sec, &request->reply.tval_sec)
+	    || __get_user(req32.reply.tval_usec, &request->reply.tval_usec))
+		return -EFAULT;
+
+	if (copy_to_user(argp, &req32, sizeof(req32)))
+		return -EFAULT;
+
+	return 0;
+}
+
+drm_ioctl_compat_t *drm_compat_ioctls[] = {
+	[DRM_IOCTL_NR(DRM_IOCTL_VERSION32)] = compat_drm_version,
+	[DRM_IOCTL_NR(DRM_IOCTL_GET_UNIQUE32)] = compat_drm_getunique,
+	[DRM_IOCTL_NR(DRM_IOCTL_GET_MAP32)] = compat_drm_getmap,
+	[DRM_IOCTL_NR(DRM_IOCTL_GET_CLIENT32)] = compat_drm_getclient,
+	[DRM_IOCTL_NR(DRM_IOCTL_GET_STATS32)] = compat_drm_getstats,
+	[DRM_IOCTL_NR(DRM_IOCTL_SET_UNIQUE32)] = compat_drm_setunique,
+	[DRM_IOCTL_NR(DRM_IOCTL_ADD_MAP32)] = compat_drm_addmap,
+	[DRM_IOCTL_NR(DRM_IOCTL_ADD_BUFS32)] = compat_drm_addbufs,
+	[DRM_IOCTL_NR(DRM_IOCTL_MARK_BUFS32)] = compat_drm_markbufs,
+	[DRM_IOCTL_NR(DRM_IOCTL_INFO_BUFS32)] = compat_drm_infobufs,
+	[DRM_IOCTL_NR(DRM_IOCTL_MAP_BUFS32)] = compat_drm_mapbufs,
+	[DRM_IOCTL_NR(DRM_IOCTL_FREE_BUFS32)] = compat_drm_freebufs,
+	[DRM_IOCTL_NR(DRM_IOCTL_RM_MAP32)] = compat_drm_rmmap,
+	[DRM_IOCTL_NR(DRM_IOCTL_SET_SAREA_CTX32)] = compat_drm_setsareactx,
+	[DRM_IOCTL_NR(DRM_IOCTL_GET_SAREA_CTX32)] = compat_drm_getsareactx,
+	[DRM_IOCTL_NR(DRM_IOCTL_RES_CTX32)] = compat_drm_resctx,
+	[DRM_IOCTL_NR(DRM_IOCTL_DMA32)] = compat_drm_dma,
+#if __OS_HAS_AGP
+	[DRM_IOCTL_NR(DRM_IOCTL_AGP_ENABLE32)] = compat_drm_agp_enable,
+	[DRM_IOCTL_NR(DRM_IOCTL_AGP_INFO32)] = compat_drm_agp_info,
+	[DRM_IOCTL_NR(DRM_IOCTL_AGP_ALLOC32)] = compat_drm_agp_alloc,
+	[DRM_IOCTL_NR(DRM_IOCTL_AGP_FREE32)] = compat_drm_agp_free,
+	[DRM_IOCTL_NR(DRM_IOCTL_AGP_BIND32)] = compat_drm_agp_bind,
+	[DRM_IOCTL_NR(DRM_IOCTL_AGP_UNBIND32)] = compat_drm_agp_unbind,
+#endif
+	[DRM_IOCTL_NR(DRM_IOCTL_SG_ALLOC32)] = compat_drm_sg_alloc,
+	[DRM_IOCTL_NR(DRM_IOCTL_SG_FREE32)] = compat_drm_sg_free,
+	[DRM_IOCTL_NR(DRM_IOCTL_WAIT_VBLANK32)] = compat_drm_wait_vblank,
+};
+
+/**
+ * Called whenever a 32-bit process running under a 64-bit kernel
+ * performs an ioctl on /dev/drm.
+ *
+ * \param filp file pointer.
+ * \param cmd command.
+ * \param arg user argument.
+ * \return zero on success or negative number on failure.
+ */
+long drm_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	unsigned int nr = DRM_IOCTL_NR(cmd);
+	drm_ioctl_compat_t *fn;
+	int ret;
+
+	if (nr >= DRM_ARRAY_SIZE(drm_compat_ioctls))
+		return -ENOTTY;
+
+	fn = drm_compat_ioctls[nr];
+
+	lock_kernel();		/* XXX for now */
+	if (fn != NULL)
+		ret = (*fn)(filp, cmd, arg);
+	else
+		ret = drm_ioctl(filp->f_dentry->d_inode, filp, cmd, arg);
+	unlock_kernel();
+
+	return ret;
+}
+EXPORT_SYMBOL(drm_compat_ioctl);

drivers/char/drm/radeon_drv.c

@@ -101,6 +101,9 @@ static struct drm_driver driver = {
 		.mmap = drm_mmap,
 		.poll = drm_poll,
 		.fasync = drm_fasync,
+#ifdef CONFIG_COMPAT
+		.compat_ioctl = radeon_compat_ioctl,
+#endif
 	},
 	.pci_driver = {
 		.name          = DRIVER_NAME,

drivers/char/drm/radeon_drv.h

@@ -317,6 +317,9 @@ extern int radeon_preinit( struct drm_device *dev, unsigned long flags );
 extern int radeon_postinit( struct drm_device *dev, unsigned long flags );
 extern int radeon_postcleanup( struct drm_device *dev );
 
+extern long radeon_compat_ioctl(struct file *filp, unsigned int cmd,
+				unsigned long arg);
+
 /* Flags for stats.boxes
  */
 #define RADEON_BOX_DMA_IDLE      0x1

drivers/char/drm/radeon_ioc32.c

+/**
+ * \file radeon_ioc32.c
+ *
+ * 32-bit ioctl compatibility routines for the Radeon DRM.
+ *
+ * \author Paul Mackerras <paulus@samba.org>
+ *
+ * Copyright (C) Paul Mackerras 2005
+ * All Rights Reserved.
+ *
+ * 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
+ * THE AUTHOR 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 <linux/compat.h>
+#include <linux/ioctl32.h>
+
+#include "drmP.h"
+#include "drm.h"
+#include "radeon_drm.h"
+#include "radeon_drv.h"
+
+typedef struct drm_radeon_init32 {
+	int func;
+	u32 sarea_priv_offset;
+	int is_pci;
+	int cp_mode;
+	int gart_size;
+	int ring_size;
+	int usec_timeout;
+
+	unsigned int fb_bpp;
+	unsigned int front_offset, front_pitch;
+	unsigned int back_offset, back_pitch;
+	unsigned int depth_bpp;
+	unsigned int depth_offset, depth_pitch;
+
+	u32 fb_offset;
+	u32 mmio_offset;
+	u32 ring_offset;
+	u32 ring_rptr_offset;
+	u32 buffers_offset;
+	u32 gart_textures_offset;
+} drm_radeon_init32_t;
+
+static int compat_radeon_cp_init(struct file *file, unsigned int cmd,
+				 unsigned long arg)
+{
+	drm_radeon_init32_t init32;
+	drm_radeon_init_t __user *init;
+
+	if (copy_from_user(&init32, (void __user *)arg, sizeof(init32)))
+		return -EFAULT;
+
+	init = compat_alloc_user_space(sizeof(*init));
+	if (!access_ok(VERIFY_WRITE, init, sizeof(*init))
+	    || __put_user(init32.func, &init->func)
+	    || __put_user(init32.sarea_priv_offset, &init->sarea_priv_offset)
+	    || __put_user(init32.is_pci, &init->is_pci)
+	    || __put_user(init32.cp_mode, &init->cp_mode)
+	    || __put_user(init32.gart_size, &init->gart_size)
+	    || __put_user(init32.ring_size, &init->ring_size)
+	    || __put_user(init32.usec_timeout, &init->usec_timeout)
+	    || __put_user(init32.fb_bpp, &init->fb_bpp)
+	    || __put_user(init32.front_offset, &init->front_offset)
+	    || __put_user(init32.front_pitch, &init->front_pitch)
+	    || __put_user(init32.back_offset, &init->back_offset)
+	    || __put_user(init32.back_pitch, &init->back_pitch)
+	    || __put_user(init32.depth_bpp, &init->depth_bpp)
+	    || __put_user(init32.depth_offset, &init->depth_offset)
+	    || __put_user(init32.depth_pitch, &init->depth_pitch)
+	    || __put_user(init32.fb_offset, &init->fb_offset)
+	    || __put_user(init32.mmio_offset, &init->mmio_offset)
+	    || __put_user(init32.ring_offset, &init->ring_offset)
+	    || __put_user(init32.ring_rptr_offset, &init->ring_rptr_offset)
+	    || __put_user(init32.buffers_offset, &init->buffers_offset)
+	    || __put_user(init32.gart_textures_offset,
+			  &init->gart_textures_offset))
+		return -EFAULT;
+
+	return drm_ioctl(file->f_dentry->d_inode, file,
+			 DRM_IOCTL_RADEON_CP_INIT, (unsigned long) init);
+}
+
+typedef struct drm_radeon_clear32 {
+	unsigned int flags;
+	unsigned int clear_color;
+	unsigned int clear_depth;
+	unsigned int color_mask;
+	unsigned int depth_mask;   /* misnamed field:  should be stencil */
+	u32	     depth_boxes;
+} drm_radeon_clear32_t;
+
+static int compat_radeon_cp_clear(struct file *file, unsigned int cmd,
+				  unsigned long arg)
+{
+	drm_radeon_clear32_t clr32;
+	drm_radeon_clear_t __user *clr;
+
+	if (copy_from_user(&clr32, (void __user *)arg, sizeof(clr32)))
+		return -EFAULT;
+
+	clr = compat_alloc_user_space(sizeof(*clr));
+	if (!access_ok(VERIFY_WRITE, clr, sizeof(*clr))
+	    || __put_user(clr32.flags, &clr->flags)
+	    || __put_user(clr32.clear_color, &clr->clear_color)
+	    || __put_user(clr32.clear_depth, &clr->clear_depth)
+	    || __put_user(clr32.color_mask, &clr->color_mask)
+	    || __put_user(clr32.depth_mask, &clr->depth_mask)
+	    || __put_user((void __user *)(unsigned long)clr32.depth_boxes,
+			  &clr->depth_boxes))
+		return -EFAULT;
+
+	return drm_ioctl(file->f_dentry->d_inode, file,
+			 DRM_IOCTL_RADEON_CLEAR, (unsigned long) clr);
+}
+
+typedef struct drm_radeon_stipple32 {
+	u32 mask;
+} drm_radeon_stipple32_t;
+
+static int compat_radeon_cp_stipple(struct file *file, unsigned int cmd,
+				    unsigned long arg)
+{
+	drm_radeon_stipple32_t __user *argp = (void __user *) arg;
+	drm_radeon_stipple_t __user *request;
+	u32 mask;
+
+	if (get_user(mask, &argp->mask))
+		return -EFAULT;
+
+	request = compat_alloc_user_space(sizeof(*request));
+	if (!access_ok(VERIFY_WRITE, request, sizeof(*request))
+	    || __put_user((unsigned int __user *)(unsigned long) mask,
+			  &request->mask))
+		return -EFAULT;
+
+	return drm_ioctl(file->f_dentry->d_inode, file,
+			 DRM_IOCTL_RADEON_STIPPLE, (unsigned long) request);
+}
+
+typedef struct drm_radeon_tex_image32 {
+	unsigned int x, y;		/* Blit coordinates */
+	unsigned int width, height;
+	u32 data;
+} drm_radeon_tex_image32_t;
+
+typedef struct drm_radeon_texture32 {
+	unsigned int offset;
+	int pitch;
+	int format;
+	int width;			/* Texture image coordinates */
+	int height;
+	u32 image;
+} drm_radeon_texture32_t;
+
+static int compat_radeon_cp_texture(struct file *file, unsigned int cmd,
+				    unsigned long arg)
+{
+	drm_radeon_texture32_t req32;
+	drm_radeon_texture_t __user *request;
+	drm_radeon_tex_image32_t img32;
+	drm_radeon_tex_image_t __user *image;
+
+	if (copy_from_user(&req32, (void __user *) arg, sizeof(req32)))
+		return -EFAULT;
+	if (req32.image == 0)
+		return -EINVAL;
+	if (copy_from_user(&img32, (void __user *)(unsigned long)req32.image,
+			   sizeof(img32)))
+		return -EFAULT;
+
+	request = compat_alloc_user_space(sizeof(*request) + sizeof(*image));
+	if (!access_ok(VERIFY_WRITE, request,
+		       sizeof(*request) + sizeof(*image)))
+		return -EFAULT;
+	image = (drm_radeon_tex_image_t __user *) (request + 1);
+
+	if (__put_user(req32.offset, &request->offset)
+	    || __put_user(req32.pitch, &request->pitch)
+	    || __put_user(req32.format, &request->format)
+	    || __put_user(req32.width, &request->width)
+	    || __put_user(req32.height, &request->height)
+	    || __put_user(image, &request->image)
+	    || __put_user(img32.x, &image->x)
+	    || __put_user(img32.y, &image->y)
+	    || __put_user(img32.width, &image->width)
+	    || __put_user(img32.height, &image->height)
+	    || __put_user((const void __user *)(unsigned long)img32.data,
+			  &image->data))
+		return -EFAULT;
+
+	return drm_ioctl(file->f_dentry->d_inode, file,
+			 DRM_IOCTL_RADEON_TEXTURE, (unsigned long) request);
+}
+
+typedef struct drm_radeon_vertex2_32 {
+	int idx;			/* Index of vertex buffer */
+	int discard;			/* Client finished with buffer? */
+	int nr_states;
+	u32 state;
+	int nr_prims;
+	u32 prim;
+} drm_radeon_vertex2_32_t;
+
+static int compat_radeon_cp_vertex2(struct file *file, unsigned int cmd,
+				    unsigned long arg)
+{
+	drm_radeon_vertex2_32_t req32;
+	drm_radeon_vertex2_t __user *request;
+
+	if (copy_from_user(&req32, (void __user *) arg, sizeof(req32)))
+		return -EFAULT;
+
+	request = compat_alloc_user_space(sizeof(*request));
+	if (!access_ok(VERIFY_WRITE, request, sizeof(*request))
+	    || __put_user(req32.idx, &request->idx)
+	    || __put_user(req32.discard, &request->discard)
+	    || __put_user(req32.nr_states, &request->nr_states)
+	    || __put_user((void __user *)(unsigned long)req32.state,
+			  &request->state)
+	    || __put_user(req32.nr_prims, &request->nr_prims)
+	    || __put_user((void __user *)(unsigned long)req32.prim,
+			  &request->prim))
+		return -EFAULT;
+
+	return drm_ioctl(file->f_dentry->d_inode, file,
+			 DRM_IOCTL_RADEON_VERTEX2, (unsigned long) request);
+}
+
+typedef struct drm_radeon_cmd_buffer32 {
+	int bufsz;
+	u32 buf;
+	int nbox;
+	u32 boxes;
+} drm_radeon_cmd_buffer32_t;
+
+static int compat_radeon_cp_cmdbuf(struct file *file, unsigned int cmd,
+				   unsigned long arg)
+{
+	drm_radeon_cmd_buffer32_t req32;
+	drm_radeon_cmd_buffer_t __user *request;
+
+	if (copy_from_user(&req32, (void __user *) arg, sizeof(req32)))
+		return -EFAULT;
+
+	request = compat_alloc_user_space(sizeof(*request));
+	if (!access_ok(VERIFY_WRITE, request, sizeof(*request))
+	    || __put_user(req32.bufsz, &request->bufsz)
+	    || __put_user((void __user *)(unsigned long)req32.buf,
+			  &request->buf)
+	    || __put_user(req32.nbox, &request->nbox)
+	    || __put_user((void __user *)(unsigned long)req32.boxes,
+			  &request->boxes))
+		return -EFAULT;
+
+	return drm_ioctl(file->f_dentry->d_inode, file,
+			 DRM_IOCTL_RADEON_CMDBUF, (unsigned long) request);
+}
+
+typedef struct drm_radeon_getparam32 {
+	int param;
+	u32 value;
+} drm_radeon_getparam32_t;
+
+static int compat_radeon_cp_getparam(struct file *file, unsigned int cmd,
+				     unsigned long arg)
+{
+	drm_radeon_getparam32_t req32;
+	drm_radeon_getparam_t __user *request;
+
+	if (copy_from_user(&req32, (void __user *) arg, sizeof(req32)))
+		return -EFAULT;
+
+	request = compat_alloc_user_space(sizeof(*request));
+	if (!access_ok(VERIFY_WRITE, request, sizeof(*request))
+	    || __put_user(req32.param, &request->param)
+	    || __put_user((void __user *)(unsigned long)req32.value,
+			  &request->value))
+		return -EFAULT;
+
+	return drm_ioctl(file->f_dentry->d_inode, file,
+			 DRM_IOCTL_RADEON_GETPARAM, (unsigned long) request);
+}
+
+typedef struct drm_radeon_mem_alloc32 {
+	int region;
+	int alignment;
+	int size;
+	u32 region_offset;	/* offset from start of fb or GART */
+} drm_radeon_mem_alloc32_t;
+
+static int compat_radeon_mem_alloc(struct file *file, unsigned int cmd,
+				   unsigned long arg)
+{
+	drm_radeon_mem_alloc32_t req32;
+	drm_radeon_mem_alloc_t __user *request;
+
+	if (copy_from_user(&req32, (void __user *) arg, sizeof(req32)))
+		return -EFAULT;
+
+	request = compat_alloc_user_space(sizeof(*request));
+	if (!access_ok(VERIFY_WRITE, request, sizeof(*request))
+	    || __put_user(req32.region, &request->region)
+	    || __put_user(req32.alignment, &request->alignment)
+	    || __put_user(req32.size, &request->size)
+	    || __put_user((int __user *)(unsigned long)req32.region_offset,
+			  &request->region_offset))
+		return -EFAULT;
+
+	return drm_ioctl(file->f_dentry->d_inode, file,
+			 DRM_IOCTL_RADEON_ALLOC, (unsigned long) request);
+}
+
+typedef struct drm_radeon_irq_emit32 {
+	u32 irq_seq;
+} drm_radeon_irq_emit32_t;
+
+static int compat_radeon_irq_emit(struct file *file, unsigned int cmd,
+				  unsigned long arg)
+{
+	drm_radeon_irq_emit32_t req32;
+	drm_radeon_irq_emit_t __user *request;
+
+	if (copy_from_user(&req32, (void __user *) arg, sizeof(req32)))
+		return -EFAULT;
+
+	request = compat_alloc_user_space(sizeof(*request));
+	if (!access_ok(VERIFY_WRITE, request, sizeof(*request))
+	    || __put_user((int __user *)(unsigned long)req32.irq_seq,
+			  &request->irq_seq))
+		return -EFAULT;
+
+	return drm_ioctl(file->f_dentry->d_inode, file,
+			 DRM_IOCTL_RADEON_IRQ_EMIT, (unsigned long) request);
+}
+
+drm_ioctl_compat_t *radeon_compat_ioctls[] = {
+	[DRM_RADEON_CP_INIT] = compat_radeon_cp_init,
+	[DRM_RADEON_CLEAR] = compat_radeon_cp_clear,
+	[DRM_RADEON_STIPPLE] = compat_radeon_cp_stipple,
+	[DRM_RADEON_TEXTURE] = compat_radeon_cp_texture,
+	[DRM_RADEON_VERTEX2] = compat_radeon_cp_vertex2,
+	[DRM_RADEON_CMDBUF] = compat_radeon_cp_cmdbuf,
+	[DRM_RADEON_GETPARAM] = compat_radeon_cp_getparam,
+	[DRM_RADEON_ALLOC] = compat_radeon_mem_alloc,
+	[DRM_RADEON_IRQ_EMIT] = compat_radeon_irq_emit,
+};
+
+/**
+ * Called whenever a 32-bit process running under a 64-bit kernel
+ * performs an ioctl on /dev/dri/card<n>.
+ *
+ * \param filp file pointer.
+ * \param cmd command.
+ * \param arg user argument.
+ * \return zero on success or negative number on failure.
+ */
+long radeon_compat_ioctl(struct file *filp, unsigned int cmd,
+			 unsigned long arg)
+{
+	unsigned int nr = DRM_IOCTL_NR(cmd);
+	drm_ioctl_compat_t *fn = NULL;
+	int ret;
+
+	if (nr < DRM_COMMAND_BASE)
+		return drm_compat_ioctl(filp, cmd, arg);
+
+	if (nr < DRM_COMMAND_BASE + DRM_ARRAY_SIZE(radeon_compat_ioctls))
+		fn = radeon_compat_ioctls[nr - DRM_COMMAND_BASE];
+
+	lock_kernel();		/* XXX for now */
+	if (fn != NULL)
+		ret = (*fn)(filp, cmd, arg);
+	else
+		ret = drm_ioctl(filp->f_dentry->d_inode, filp, cmd, arg);
+	unlock_kernel();
+
+	return ret;
+}