drivers/gpu/drm/i915/i915_ioc32.c

   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/drmP.h>
  32 #include <drm/i915_drm.h>
  33 #include "i915_drv.h"
  34
  35 struct drm_i915_getparam32 {
  36         s32 param;
  37         /*
  38          * We screwed up the generic ioctl struct here and used a variable-sized
  39          * pointer. Use u32 in the compat struct to match the 32bit pointer
  40          * userspace expects.
  41          */
  42         u32 value;
  43 };
  44
  45 static int compat_i915_getparam(struct file *file, unsigned int cmd,
  46                                 unsigned long arg)
  47 {
  48         struct drm_i915_getparam32 req32;
  49         drm_i915_getparam_t __user *request;
  50
  51         if (copy_from_user(&req32, (void __user *)arg, sizeof(req32)))
  52                 return -EFAULT;
  53
  54         request = compat_alloc_user_space(sizeof(*request));
  55         if (!access_ok(VERIFY_WRITE, request, sizeof(*request)) ||
  56             __put_user(req32.param, &request->param) ||
  57             __put_user((void __user *)(unsigned long)req32.value,
  58                        &request->value))
  59                 return -EFAULT;
  60
  61         return drm_ioctl(file, DRM_IOCTL_I915_GETPARAM,
  62                          (unsigned long)request);
  63 }
  64
  65 static drm_ioctl_compat_t *i915_compat_ioctls[] = {
  66         [DRM_I915_GETPARAM] = compat_i915_getparam,
  67 };
  68
  69 /**
  70  * i915_compat_ioctl - handle the mistakes of the past
  71  * @filp: the file pointer
  72  * @cmd: the ioctl command (and encoded flags)
  73  * @arg: the ioctl argument (from userspace)
  74  *
  75  * Called whenever a 32-bit process running under a 64-bit kernel
  76  * performs an ioctl on /dev/dri/card<n>.
  77  */
  78 long i915_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
  79 {
  80         unsigned int nr = DRM_IOCTL_NR(cmd);
  81         drm_ioctl_compat_t *fn = NULL;
  82         int ret;
  83
  84         if (nr < DRM_COMMAND_BASE || nr >= DRM_COMMAND_END)
  85                 return drm_compat_ioctl(filp, cmd, arg);
  86
  87         if (nr < DRM_COMMAND_BASE + ARRAY_SIZE(i915_compat_ioctls))
  88                 fn = i915_compat_ioctls[nr - DRM_COMMAND_BASE];
  89
  90         if (fn != NULL)
  91                 ret = (*fn) (filp, cmd, arg);
  92         else
  93                 ret = drm_ioctl(filp, cmd, arg);
  94
  95         return ret;
  96 }