From owner-freebsd-hackers Fri Nov 7 18:42:41 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id SAA11190 for hackers-outgoing; Fri, 7 Nov 1997 18:42:41 -0800 (PST) (envelope-from owner-freebsd-hackers) Received: from word.smith.net.au (word.smith.net.au [202.0.75.3]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id SAA11185 for ; Fri, 7 Nov 1997 18:42:27 -0800 (PST) (envelope-from mike@word.smith.net.au) Received: from word.smith.net.au (localhost.smith.net.au [127.0.0.1]) by word.smith.net.au (8.8.7/8.8.5) with ESMTP id NAA00641; Sat, 8 Nov 1997 13:08:14 +1030 (CST) Message-Id: <199711080238.NAA00641@word.smith.net.au> X-Mailer: exmh version 2.0zeta 7/24/97 To: Jonathan Mini cc: hackers@FreeBSD.ORG Subject: Re: x86 gods; advice? Suggestions? In-reply-to: Your message of "Fri, 07 Nov 1997 18:16:14 -0800." <19971107181614.32380@micron.mini.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Sat, 08 Nov 1997 13:08:13 +1030 From: Mike Smith Sender: owner-freebsd-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk > > > > It has to run with DPL = 0. > > > > > > Why? > > > > Because it has to in order to meet the spec. If you're interested, or > > think you have some ideas on this, you can grab the spec from > > microsoft's website. Make sure you get the clarification as well, as > > there's a very confusing error in one of the critical digrams... > > hehehe. It should be possible to just give it i/o access to all of the ports, > or if you feel parinoid, just a subset, and then ``emulate'' the exception 13 > instruction cases. (there aren't many) Ugh. You are taking a very small piece of code and making it *very* complicated. It *must* be called from inside the kernel because at the point where it's needed there is nowhere else to be calling it from. > Personally, I feel very insecure running a BIOS at DPL = 0. I certainly > woulndn't like letting third party software muck with everything. (even if it > is on a ROM (ok, a flashable ROM)) Like I said, if you have a better idea, I am seriously interested in pursuing it. > > It's actually pretty easy; with any luck I'll be happy enough with the > > vm86 stuff to commit it tomorrow. > > Hear me cheer! I have been working on vm86 BIOS/DOS interaction for a while > now for my own projects. If you have something elegant it will be a godsend. > :) It's not entirely elegant, or even mostly mine, but there's a single-line call you can make anywhere (once its safe to sleep) inside the kernel that will run a vm86-mode interrupt for you. mike