There was a brief discussion a few months ago on ways to give processes
that need it a full 8k I/O bitmap, using VM hacks. It came about as a
result of attempts to speed up fork() & clone(). Linus didn't like it.
I would also find this quite useful. I've been programming a PCI card
from user space, and the I/O addresses are high enough that I have to
use iopl(3). On a few occasions I mistyped some I/O instructions and
trashed the machine. With an I/O bitmap, I could guarantee the machine
would be fine whatever I wrote (it's a custom PCI card so I know which
I/O stuff is safe in this reguar), and more usefully, I could pass the
permissions on to other users who wish to experiment with the card.
(It's a custom card with reconfigurable logic interpreting the I/O, with
non-reconfigurable PCI logic, so it'd be quite safe and useful to let
general users program certain ranges of I/O ports).
-- Jamie
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.altern.org/andrebalsa/doc/lkml-faq.html