Subject: Re: compartmentalization of kernel memory
To: David Laight <firstname.lastname@example.org>
From: Richard Earnshaw <email@example.com>
Date: 04/06/2003 18:01:55
> > Now, ARM is a different matter - on that one the best we managed was read-only.
> > If anybody knows how to make ARM's zero page inaccessible, I'd sure be
> > interested to hear it.
Just don't give the first page any user access (the kernel needs it, or
you'll end up with infinite page-faults when the processor takes an
interrupt or any other fault). That's the way the ARM pmap works.
> Doesn't the SA1100 (at least) let you move the table to an alternate
> (fixed and not particularly useful) address?
Some processors have high vectors (at 0xffff0000-0xffff001c) as an option.
(See ARM ARM Section 2.6.9).
> Could the 16 protection bits (forgotten what they are called) be used??
No, don't try to use the domains system.