On Fri, Aug 27, 2004 at 01:04:15PM -0700, David S. Miller wrote:
> On Fri, 27 Aug 2004 15:13:54 +0100 (IST)
> Dave Airlie <airlied@linux.ie> wrote:
> 
> >    the patch below optimises the drm code to not do put_user() on memory the
> >    kernel allocated and then mmap-installed to userspace, but instead makes it
> >    use the kernel virtual address directly instead.
> 
> This might cause major problems on systems with virtually indexed
> caches if precautions are not made at buffer allocation time such
> that the virtual cache color of the kernel mapping is the same
> as the user mapping.

actually it's uncachable memory ;)