drivers/gpu/drm/i915/i915_ioc32.c

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