L4 Mapping question

[Adam 'WeirdArms' Wiggins]

On 23 Feb 1999, Michael Hohmuth wrote:

> vuhlig at us.ibm.com writes:
> 
> > The idea is, that the kernel can revoke pages from sigma 0, what is not
> > implemented yet.  [...]
> 
> I don't think it is a part of the Sigma0 specification that Sigma0
> should be able to handle the case where the kernel revokes mappings of
> pages mapped into Sigma0.  Instead, Sigma0 is pretty safe to assume
> that it magically owns---and has access to---all physically-
> addressable memory (maybe with the exception of the kernel-private
> code and data sections; the experts are still out on this one).

	The HotOS paper on secure web OS's outlines a sigma0 where a task
requesting a page mapping donates memory back to sigma zero which is then
allocated to the kernel for page table memory. It also mentions using
sigma1 as a TCB pager. Unfortunately no details are really outlined for a
protocol. Has anyone been working on this?

	Cheers Adam
 > 
> Michael
> -- 
> hohmuth at innocent.com, hohmuth at inf.tu-dresden.de
> http://home.pages.de/~hohmuth/
>