xref: /openbmc/linux/drivers/gpu/drm/i915/i915_ioc32.c (revision 9a29f5fc)
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_getparam.h"
35 #include "i915_ioc32.h"
36 
37 struct drm_i915_getparam32 {
38 	s32 param;
39 	/*
40 	 * We screwed up the generic ioctl struct here and used a variable-sized
41 	 * pointer. Use u32 in the compat struct to match the 32bit pointer
42 	 * userspace expects.
43 	 */
44 	u32 value;
45 };
46 
47 static int compat_i915_getparam(struct file *file, unsigned int cmd,
48 				unsigned long arg)
49 {
50 	struct drm_i915_getparam32 req32;
51 	struct drm_i915_getparam req;
52 
53 	if (copy_from_user(&req32, (void __user *)arg, sizeof(req32)))
54 		return -EFAULT;
55 
56 	req.param = req32.param;
57 	req.value = compat_ptr(req32.value);
58 
59 	return drm_ioctl_kernel(file, i915_getparam_ioctl, &req,
60 				DRM_RENDER_ALLOW);
61 }
62 
63 static drm_ioctl_compat_t *i915_compat_ioctls[] = {
64 	[DRM_I915_GETPARAM] = compat_i915_getparam,
65 };
66 
67 /**
68  * i915_ioc32_compat_ioctl - handle the mistakes of the past
69  * @filp: the file pointer
70  * @cmd: the ioctl command (and encoded flags)
71  * @arg: the ioctl argument (from userspace)
72  *
73  * Called whenever a 32-bit process running under a 64-bit kernel
74  * performs an ioctl on /dev/dri/card<n>.
75  */
76 long i915_ioc32_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
77 {
78 	unsigned int nr = DRM_IOCTL_NR(cmd);
79 	drm_ioctl_compat_t *fn = NULL;
80 	int ret;
81 
82 	if (nr < DRM_COMMAND_BASE || nr >= DRM_COMMAND_END)
83 		return drm_compat_ioctl(filp, cmd, arg);
84 
85 	if (nr < DRM_COMMAND_BASE + ARRAY_SIZE(i915_compat_ioctls))
86 		fn = i915_compat_ioctls[nr - DRM_COMMAND_BASE];
87 
88 	if (fn != NULL)
89 		ret = (*fn) (filp, cmd, arg);
90 	else
91 		ret = drm_ioctl(filp, cmd, arg);
92 
93 	return ret;
94 }
95