[PATCH] drm: Provide compat ioctl for addfb2.1

[Rob Clark]

btw, I mentioned on irc, but someone *really* ought to go through the
ioclt structs and split each struct member into it's own line, so
things like '__u32 width, height' aren't so sneaky ;-)

On Mon, Jul 13, 2015 at 11:56 AM, Tvrtko Ursulin
<tvrtko.ursulin at linux.intel.com> wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>
> Frame buffer modifiers extensions provided in;
>
>   commit e3eb3250d84ef97b766312345774367b6a310db8
>   Author: Rob Clark <robdclark at gmail.com>
>   Date:   Thu Feb 5 14:41:52 2015 +0000
>
>       drm: add support for tiled/compressed/etc modifier in addfb2
>
> Missed the structure packing/alignment problem where 64-bit
> members were added after the odd number of 32-bit ones. This
> makes the compiler produce structures of different sizes under
> 32- and 64-bit x86 targets and makes the ioctl need explicit
> compat handling.
>
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Cc: dri-devel at lists.freedesktop.org
> Cc: Rob Clark <robdclark at gmail.com>
> Cc: Daniel Stone <daniels at collabora.com>
> Cc: Daniel Vetter <daniel.vetter at intel.com>
> ---
>  drivers/gpu/drm/drm_ioc32.c | 60 +++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 60 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_ioc32.c b/drivers/gpu/drm/drm_ioc32.c
> index aa8bbb460c57..2bea11bfb3ae 100644
> --- a/drivers/gpu/drm/drm_ioc32.c
> +++ b/drivers/gpu/drm/drm_ioc32.c
> @@ -70,6 +70,8 @@
>
>  #define DRM_IOCTL_WAIT_VBLANK32                DRM_IOWR(0x3a, drm_wait_vblank32_t)
>
> +#define DRM_IOCTL_MODE_ADDFB232                DRM_IOWR(0xb8, drm_mode_fb_cmd232_t)
> +
>  typedef struct drm_version_32 {
>         int version_major;        /**< Major version */
>         int version_minor;        /**< Minor version */
> @@ -1016,6 +1018,63 @@ static int compat_drm_wait_vblank(struct file *file, unsigned int cmd,
>         return 0;
>  }
>
> +typedef struct drm_mode_fb_cmd232 {
> +       u32 fb_id;
> +       u32 width;
> +       u32 height;
> +       u32 pixel_format;
> +       u32 flags;
> +       u32 handles[4];
> +       u32 pitches[4];
> +       u32 offsets[4];
> +       u64 modifier[4];
> +} __attribute__((packed)) drm_mode_fb_cmd232_t;
> +
> +static int compat_drm_mode_addfb2(struct file *file, unsigned int cmd,
> +                                 unsigned long arg)
> +{
> +       drm_mode_fb_cmd232_t __user *argp = (void __user *)arg;
> +       struct drm_mode_fb_cmd232 req32;
> +       struct drm_mode_fb_cmd2 __user *req64;
> +       int i;
> +       int err;
> +
> +       if (copy_from_user(&req32, argp, sizeof(req32)))
> +               return -EFAULT;
> +
> +       req64 = compat_alloc_user_space(sizeof(*req64));
> +
> +       if (!access_ok(VERIFY_WRITE, req64, sizeof(*req64))
> +           || __put_user(req32.width, &req64->width)
> +           || __put_user(req32.height, &req64->height)
> +           || __put_user(req32.pixel_format, &req64->pixel_format)
> +           || __put_user(req32.flags, &req64->flags))
> +               return -EFAULT;
> +
> +       for (i = 0; i < 4; i++) {
> +               if (__put_user(req32.handles[i], &req64->handles[i]))
> +                       return -EFAULT;
> +               if (__put_user(req32.pitches[i], &req64->pitches[i]))
> +                       return -EFAULT;
> +               if (__put_user(req32.offsets[i], &req64->offsets[i]))
> +                       return -EFAULT;
> +               if (__put_user(req32.modifier[i], &req64->modifier[i]))
> +                       return -EFAULT;
> +       }
> +
> +       err = drm_ioctl(file, DRM_IOCTL_MODE_ADDFB2, (unsigned long)req64);
> +       if (err)
> +               return err;
> +
> +       if (__get_user(req32.fb_id, &req64->fb_id))
> +               return -EFAULT;
> +
> +       if (copy_to_user(argp, &req32, sizeof(req32)))
> +               return -EFAULT;
> +
> +       return 0;
> +}
> +
>  static drm_ioctl_compat_t *drm_compat_ioctls[] = {
>         [DRM_IOCTL_NR(DRM_IOCTL_VERSION32)] = compat_drm_version,
>         [DRM_IOCTL_NR(DRM_IOCTL_GET_UNIQUE32)] = compat_drm_getunique,
> @@ -1048,6 +1107,7 @@ static drm_ioctl_compat_t *drm_compat_ioctls[] = {
>         [DRM_IOCTL_NR(DRM_IOCTL_UPDATE_DRAW32)] = compat_drm_update_draw,
>  #endif
>         [DRM_IOCTL_NR(DRM_IOCTL_WAIT_VBLANK32)] = compat_drm_wait_vblank,
> +       [DRM_IOCTL_NR(DRM_IOCTL_MODE_ADDFB232)] = compat_drm_mode_addfb2,
>  };
>
>  /**
> --
> 2.4.2
>