Bugtraq: Re: http://www.smashguard.org

[Nicholas Weaver <nweaver () CS berkeley edu>]

On Fri, Apr 30, 2004 at 01:29:21AM +0200, Pavel Machek composed:
> Well.. they are not really separate bits.
>
> If they was, you'd have ---, --x, r--, r-x. You can't have --x
> combination (which is sad for the emulators).
>
> I believe that on most sane architectures (m68k at least), you can
> have all 4 combinations.
Silly confusion time:

The key is good separation of WRITE and EXECUTE.  Far too many CPUs
don't have separate TLB bits for writeable and executable.


-- 
Nicholas C. Weaver                                 nweaver () cs berkeley edu