From owner-freebsd-hackers Wed May 5 2:18:30 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from herring.nlsystems.com (nlsys.demon.co.uk [158.152.125.33]) by hub.freebsd.org (Postfix) with ESMTP id AFBD214CE2 for ; Wed, 5 May 1999 02:18:27 -0700 (PDT) (envelope-from dfr@nlsystems.com) Received: from localhost (dfr@localhost) by herring.nlsystems.com (8.9.3/8.8.8) with ESMTP id KAA00656; Wed, 5 May 1999 10:18:23 +0100 (BST) (envelope-from dfr@nlsystems.com) Date: Wed, 5 May 1999 10:18:23 +0100 (BST) From: Doug Rabson To: CyberPsychotic Cc: freebsd-hackers@freebsd.org, tech@openbsd.org Subject: Re: io ports reading/writing In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Wed, 5 May 1999, CyberPsychotic wrote: > ~ > ~ The access control for io ports is controlled by the file-system > ~ permissions on /dev/io. In a standard setup, only root can access this > ~ device. > ~ > > yes. But I was refering to linux scheme, where you can set the port-range, > so the code wouldn't make any unintentional damage. (like if you're working > with cmos you could only permit 0x70/0x71 ports, so even if code goes nuts, > your disks will be safe). This is basically programmer's problem of course, > but the feature is very handy. I don't quite understand the i386 architecture at this level but I seem to remember that this support would require significant changes in the way we handle processes and there might have been some performance implications. I don't think its a big problem in practice. -- Doug Rabson Mail: dfr@nlsystems.com Nonlinear Systems Ltd. Phone: +44 181 442 9037 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message