xref: /openbmc/linux/drivers/gpu/drm/i915/i915_ioc32.c (revision 6c33a6f4)
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 	drm_i915_getparam_t __user *request;
51 
52 	if (copy_from_user(&req32, (void __user *)arg, sizeof(req32)))
53 		return -EFAULT;
54 
55 	request = compat_alloc_user_space(sizeof(*request));
56 	if (!access_ok(request, sizeof(*request)) ||
57 	    __put_user(req32.param, &request->param) ||
58 	    __put_user((void __user *)(unsigned long)req32.value,
59 		       &request->value))
60 		return -EFAULT;
61 
62 	return drm_ioctl(file, DRM_IOCTL_I915_GETPARAM,
63 			 (unsigned long)request);
64 }
65 
66 static drm_ioctl_compat_t *i915_compat_ioctls[] = {
67 	[DRM_I915_GETPARAM] = compat_i915_getparam,
68 };
69 
70 /**
71  * i915_ioc32_compat_ioctl - handle the mistakes of the past
72  * @filp: the file pointer
73  * @cmd: the ioctl command (and encoded flags)
74  * @arg: the ioctl argument (from userspace)
75  *
76  * Called whenever a 32-bit process running under a 64-bit kernel
77  * performs an ioctl on /dev/dri/card<n>.
78  */
79 long i915_ioc32_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
80 {
81 	unsigned int nr = DRM_IOCTL_NR(cmd);
82 	drm_ioctl_compat_t *fn = NULL;
83 	int ret;
84 
85 	if (nr < DRM_COMMAND_BASE || nr >= DRM_COMMAND_END)
86 		return drm_compat_ioctl(filp, cmd, arg);
87 
88 	if (nr < DRM_COMMAND_BASE + ARRAY_SIZE(i915_compat_ioctls))
89 		fn = i915_compat_ioctls[nr - DRM_COMMAND_BASE];
90 
91 	if (fn != NULL)
92 		ret = (*fn) (filp, cmd, arg);
93 	else
94 		ret = drm_ioctl(filp, cmd, arg);
95 
96 	return ret;
97 }
98