Re: is avoiding compat ioctls possible?

Andi Kleen
2009-10-28T03:19:02Z

On Wed, Oct 28, 2009 at 01:05:08PM +1000, Dave Airlie wrote:
> We've designed that into a/c also, we pad all 64-bit values to 64-bit
> alignment on all the
> ioctls we've added to the drm in the past couple of years. Just because of
> this particular insanity.

That's actually not needed, just use compat_*64.
>
> Assume no mistakes are made, new ioctls designed from scratch

That seems like a bad assumption. It sounds like you already
made some.

> and reviewed to do 32/64-bit properly. The s390 was something I didn't
> know about but KMS on s390 is probably never going to be something
> that sees the light of day.

Well in theory there might be more architectures in the future
which rely on compat_ptr

>
> I'm just amazed that compat_ioctl should be required for all new code.
>
> DrNick on irc suggested just doing:
> if (is_compat_task()) ptr &= 0x00000000FFFFFFFF;

Such hacks often have problems on BE.

-Andi

--
ak@linux.intel.com -- Speaking for myself only.