i915_ioc32.c revision 1.3 
1/*	$NetBSD: i915_ioc32.c,v 1.3 2021/12/18 23:45:28 riastradh Exp $	*/
2
3/*
4 * 32-bit ioctl compatibility routines for the i915 DRM.
5 *
6 * Copyright (C) Paul Mackerras 2005
7 * Copyright (C) Alan Hourihane 2005
8 * All Rights Reserved.
9 *
10 * Permission is hereby granted, free of charge, to any person obtaining a
11 * copy of this software and associated documentation files (the "Software"),
12 * to deal in the Software without restriction, including without limitation
13 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
14 * and/or sell copies of the Software, and to permit persons to whom the
15 * Software is furnished to do so, subject to the following conditions:
16 *
17 * The above copyright notice and this permission notice (including the next
18 * paragraph) shall be included in all copies or substantial portions of the
19 * Software.
20 *
21 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
22 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
23 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
24 * THE AUTHOR BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
25 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
26 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
27 * IN THE SOFTWARE.
28 *
29 * Author: Alan Hourihane <alanh@fairlite.demon.co.uk>
30 */
31#include <sys/cdefs.h>
32__KERNEL_RCSID(0, "$NetBSD: i915_ioc32.c,v 1.3 2021/12/18 23:45:28 riastradh Exp $");
33
34#include <linux/compat.h>
35
36#include <drm/i915_drm.h>
37#include <drm/drm_ioctl.h>
38#include "i915_drv.h"
39
40struct drm_i915_getparam32 {
41	s32 param;
42	/*
43	 * We screwed up the generic ioctl struct here and used a variable-sized
44	 * pointer. Use u32 in the compat struct to match the 32bit pointer
45	 * userspace expects.
46	 */
47	u32 value;
48};
49
50static int compat_i915_getparam(struct file *file, unsigned int cmd,
51				unsigned long arg)
52{
53	struct drm_i915_getparam32 req32;
54	drm_i915_getparam_t __user *request;
55
56	if (copy_from_user(&req32, (void __user *)arg, sizeof(req32)))
57		return -EFAULT;
58
59	request = compat_alloc_user_space(sizeof(*request));
60	if (!access_ok(request, sizeof(*request)) ||
61	    __put_user(req32.param, &request->param) ||
62	    __put_user((void __user *)(unsigned long)req32.value,
63		       &request->value))
64		return -EFAULT;
65
66	return drm_ioctl(file, DRM_IOCTL_I915_GETPARAM,
67			 (unsigned long)request);
68}
69
70static drm_ioctl_compat_t *i915_compat_ioctls[] = {
71	[DRM_I915_GETPARAM] = compat_i915_getparam,
72};
73
74/**
75 * i915_compat_ioctl - handle the mistakes of the past
76 * @filp: the file pointer
77 * @cmd: the ioctl command (and encoded flags)
78 * @arg: the ioctl argument (from userspace)
79 *
80 * Called whenever a 32-bit process running under a 64-bit kernel
81 * performs an ioctl on /dev/dri/card<n>.
82 */
83long i915_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
84{
85	unsigned int nr = DRM_IOCTL_NR(cmd);
86	drm_ioctl_compat_t *fn = NULL;
87	int ret;
88
89	if (nr < DRM_COMMAND_BASE || nr >= DRM_COMMAND_END)
90		return drm_compat_ioctl(filp, cmd, arg);
91
92	if (nr < DRM_COMMAND_BASE + ARRAY_SIZE(i915_compat_ioctls))
93		fn = i915_compat_ioctls[nr - DRM_COMMAND_BASE];
94
95	if (fn != NULL)
96		ret = (*fn) (filp, cmd, arg);
97	else
98		ret = drm_ioctl(filp, cmd, arg);
99
100	return ret;
101}
102