xref: /openbmc/linux/drivers/gpu/drm/i915/i915_ioc32.c (revision 04b3c795)
1 /*
2  * 32-bit ioctl compatibility routines for the i915 DRM.
3  *
4  * Copyright (C) Paul Mackerras 2005
5  * Copyright (C) Alan Hourihane 2005
6  * All Rights Reserved.
7  *
8  * Permission is hereby granted, free of charge, to any person obtaining a
9  * copy of this software and associated documentation files (the "Software"),
10  * to deal in the Software without restriction, including without limitation
11  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
12  * and/or sell copies of the Software, and to permit persons to whom the
13  * Software is furnished to do so, subject to the following conditions:
14  *
15  * The above copyright notice and this permission notice (including the next
16  * paragraph) shall be included in all copies or substantial portions of the
17  * Software.
18  *
19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
22  * THE AUTHOR BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
23  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
24  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
25  * IN THE SOFTWARE.
26  *
27  * Author: Alan Hourihane <alanh@fairlite.demon.co.uk>
28  */
29 #include <linux/compat.h>
30 
31 #include <drm/drm_ioctl.h>
32 
33 #include "i915_drv.h"
34 #include "i915_ioc32.h"
35 
36 struct drm_i915_getparam32 {
37 	s32 param;
38 	/*
39 	 * We screwed up the generic ioctl struct here and used a variable-sized
40 	 * pointer. Use u32 in the compat struct to match the 32bit pointer
41 	 * userspace expects.
42 	 */
43 	u32 value;
44 };
45 
46 static int compat_i915_getparam(struct file *file, unsigned int cmd,
47 				unsigned long arg)
48 {
49 	struct drm_i915_getparam32 req32;
50 	struct drm_i915_getparam req;
51 
52 	if (copy_from_user(&req32, (void __user *)arg, sizeof(req32)))
53 		return -EFAULT;
54 
55 	req.param = req32.param;
56 	req.value = compat_ptr(req32.value);
57 
58 	return drm_ioctl_kernel(file, i915_getparam_ioctl, &req,
59 				DRM_RENDER_ALLOW);
60 }
61 
62 static drm_ioctl_compat_t *i915_compat_ioctls[] = {
63 	[DRM_I915_GETPARAM] = compat_i915_getparam,
64 };
65 
66 /**
67  * i915_ioc32_compat_ioctl - handle the mistakes of the past
68  * @filp: the file pointer
69  * @cmd: the ioctl command (and encoded flags)
70  * @arg: the ioctl argument (from userspace)
71  *
72  * Called whenever a 32-bit process running under a 64-bit kernel
73  * performs an ioctl on /dev/dri/card<n>.
74  */
75 long i915_ioc32_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
76 {
77 	unsigned int nr = DRM_IOCTL_NR(cmd);
78 	drm_ioctl_compat_t *fn = NULL;
79 	int ret;
80 
81 	if (nr < DRM_COMMAND_BASE || nr >= DRM_COMMAND_END)
82 		return drm_compat_ioctl(filp, cmd, arg);
83 
84 	if (nr < DRM_COMMAND_BASE + ARRAY_SIZE(i915_compat_ioctls))
85 		fn = i915_compat_ioctls[nr - DRM_COMMAND_BASE];
86 
87 	if (fn != NULL)
88 		ret = (*fn) (filp, cmd, arg);
89 	else
90 		ret = drm_ioctl(filp, cmd, arg);
91 
92 	return ret;
93 }
94