Re: is avoiding compat ioctls possible?

Andi Kleen
2009-10-28T04:36:09Z

On Tue, Oct 27, 2009 at 08:37:09PM -0700, David Miller wrote:
> On sparc64, in order to make debugging easier, we trap any time
> the kernel does a userspace access to a compat task and any
> of the upper 32-bits are non-zero.

Interesting. That definitely means Dave needs a special path.

> > However some architectures need special operations on compat pointers
> > (s390 iirc), but if you don't support those it might be reasonable
> > to not support that.
>
> s390 has to sign extend all 32-bit compat process pointers when
> processing them in the 64-bit s390 kernel. I think one other
> architecture has this kind of situation too.

Which other architure? I reviewed all the definitions in tree
and don't see any other than s390 doing magic there.

-Andi

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