From owner-freebsd-hackers Thu Apr 16 14:57:24 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id OAA19256 for freebsd-hackers-outgoing; Thu, 16 Apr 1998 14:57:24 -0700 (PDT) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from uhf.wireless.net (uhf.wireless.net [209.189.23.54]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id VAA18705 for ; Thu, 16 Apr 1998 21:56:06 GMT (envelope-from bad@shf.wireless.net) Received: from shf.wireless.net (shf [209.189.23.56]) by uhf.wireless.net (8.8.8/8.8.7) with ESMTP id OAA01053; Thu, 16 Apr 1998 14:55:23 -0700 (PDT) Received: from localhost (bad@localhost) by shf.wireless.net (8.8.8/8.8.8) with SMTP id OAA00557; Thu, 16 Apr 1998 14:57:00 -0700 (PDT) (envelope-from bad@shf.wireless.net) Date: Thu, 16 Apr 1998 14:57:00 -0700 (PDT) From: Bernie Doehner To: Mike Smith cc: Bernie Doehner , Bernie Doehner , hackers@FreeBSD.ORG, buaas@wireless.net Subject: Re: Documentation of 2.2.5-RELEASE and 3.0 memory protection? In-Reply-To: <199804162122.OAA01195@dingo.cdrom.com> 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 > > User-mode applications cannot access memory in the ISA hole without > using mmap() to obtain such a mapping, either agains /dev/mem or some > other device. One may alternatively open /dev/mem or /dev/kmem and > read/write to achieve the same result. Didn't know that.. Guess we need to look at the /dev/mem a little closer :) > A driver is a kernel component, linked into the kernel. A user-mode > program runs as a process with user priviledges. > > > But we'd like to understand the kernel mechanisms better so that we can > > move/some of it into the kernel and turn it into real device drivers. > > The ISA hole is mapped into the kernel's address space; drivers such as > if_ed's use of memory in this range are good examples of how to locate > and work with this mapping. See also how syscons accesses the video > framebuffer. > Thanks.. Bernie To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message