Re: is avoiding compat ioctls possible?

[Maciej W. Rozycki]

On Wed, 28 Oct 2009, Andi Kleen wrote:

> > 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.

 And then some platforms (i.e. MIPS) require sign-extension rather than 
zero-extension, that is:

if (is_compat_task()) ptr = ((ptr & 0xffffffff) ^ 0x80000000) - 0x80000000;

if doing this explicitly (with compat stuff hardware will do the right 
thing automagically).

  Maciej
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/