> On architectures where the stack grows down (do we currently support
> any where the stack grows up?  I don't think so!), the stack starts at
> ((char *)p->p_addr) + USPACE, and grows down towards the U area.

Hmm, I'd thought that you should know :-)  Since you did the (quite large)
modifications of my execve implementation, and the original had this comment:

	/*
         * I think this should be vastly more machine dependent
         * (e.g. stack up/down, startup stack format etc.)
         */

I.e. the current version of our code to setup the stack of a new process
image only supports machines where the stack grows down.

Yes, I do consider this a bug (see the comment cited above).  Yes, I intend
to fix it at some time (together with some other machine dependencies in our
current execve implementation).
--
ws@TooLs.DE     (Wolfgang Solfrank, TooLs GmbH) 	+49-228-985800