From owner-cvs-src@FreeBSD.ORG Tue Oct 28 01:27:23 2003 Return-Path: Delivered-To: cvs-src@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id CEB2F16A4CE; Tue, 28 Oct 2003 01:27:23 -0800 (PST) Received: from ns1.xcllnt.net (209-128-86-226.bayarea.net [209.128.86.226]) by mx1.FreeBSD.org (Postfix) with ESMTP id 7B5B943F3F; Tue, 28 Oct 2003 01:27:20 -0800 (PST) (envelope-from marcel@xcllnt.net) Received: from dhcp01.pn.xcllnt.net (dhcp01.pn.xcllnt.net [192.168.4.201]) by ns1.xcllnt.net (8.12.9/8.12.9) with ESMTP id h9S9RKbe092805; Tue, 28 Oct 2003 01:27:20 -0800 (PST) (envelope-from marcel@piii.pn.xcllnt.net) Received: from dhcp01.pn.xcllnt.net (localhost [127.0.0.1]) h9S9RJP9044248; Tue, 28 Oct 2003 01:27:19 -0800 (PST) (envelope-from marcel@dhcp01.pn.xcllnt.net) Received: (from marcel@localhost) by dhcp01.pn.xcllnt.net (8.12.10/8.12.10/Submit) id h9S9RJ2a044247; Tue, 28 Oct 2003 01:27:19 -0800 (PST) (envelope-from marcel) Date: Tue, 28 Oct 2003 01:27:19 -0800 From: Marcel Moolenaar To: Doug Rabson Message-ID: <20031028092719.GA44213@dhcp01.pn.xcllnt.net> References: <200310272254.h9RMsZFN027412@repoman.freebsd.org> <1067332169.42914.3.camel@herring.nlsystems.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1067332169.42914.3.camel@herring.nlsystems.com> User-Agent: Mutt/1.5.4i cc: cvs-src@FreeBSD.org cc: src-committers@FreeBSD.org cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/ia64/ia64 sys_machdep.c src/sys/ia64/include sysarch.h X-BeenThere: cvs-src@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: CVS commit messages for the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 28 Oct 2003 09:27:24 -0000 On Tue, Oct 28, 2003 at 09:09:29AM +0000, Doug Rabson wrote: > Shouldn't there some kind of access control here? It appears as if > anyone at all can do inx/outx. Eventually, yes. There's a possibility that I remove these. The X server needs to be able to mmap uncachable memory for access to the hardware. This could also be used to do I/O. The only thing the kernel needs to export is the base of the memory mapped I/O space with sysctl in that case. Note that this affects the VM and PMAP interfaces :-( > Also, I have a vague feeling that the > Linux kernel manages to support userland inx/outx without system calls - > if so, how do they do that? I think mmap is used for that as well. > Possibly with modern hardware the cost of the bus transaction dwarfs the > cost of doing a system call so perhaps it doesn't matter. The sysarch approach is not optimal. I don't think it's very performance critical. Modern graphics hardware is memory mapped anyway. -- Marcel Moolenaar USPA: A-39004 marcel@xcllnt.net