Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261595AbVCNANT (ORCPT ); Sun, 13 Mar 2005 19:13:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261596AbVCNANT (ORCPT ); Sun, 13 Mar 2005 19:13:19 -0500 Received: from mail23.syd.optusnet.com.au ([211.29.133.164]:56998 "EHLO mail23.syd.optusnet.com.au") by vger.kernel.org with ESMTP id S261595AbVCNANO (ORCPT ); Sun, 13 Mar 2005 19:13:14 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <16948.55096.598031.618338@wombat.chubb.wattle.id.au> Date: Mon, 14 Mar 2005 11:13:44 +1100 From: Peter Chubb To: Greg KH Cc: Peter Chubb , linux-kernel@vger.kernel.org Subject: Re: User mode drivers: part 2: PCI device handling (patch 1/2 for 2.6.11) In-Reply-To: <20050311152106.GA32584@kroah.com> References: <16945.4717.402555.893411@berry.gelato.unsw.EDU.AU> <20050311071825.GA28613@kroah.com> <16945.22566.593812.759201@wombat.chubb.wattle.id.au> <20050311152106.GA32584@kroah.com> X-Mailer: VM 7.17 under 21.4 (patch 15) "Security Through Obscurity" XEmacs Lucid Comments: Hyperbole mail buttons accepted, v04.18. X-Face: GgFg(Z>fx((4\32hvXq<)|jndSniCH~~$D)Ka:P@e@JR1P%Vr}EwUdfwf-4j\rUs#JR{'h# !]])6%Jh~b$VA|ALhnpPiHu[-x~@<"@Iv&|%R)Fq[[,(&Z'O)Q)xCqe1\M[F8#9l8~}#u$S$Rm`S9% \'T@`:&8>Sb*c5d'=eDYI&GF`+t[LfDH="MP5rwOO]w>ALi7'=QJHz&y&C&TE_3j! Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1489 Lines: 41 >>>>> "Greg" == Greg KH writes: Greg> On Fri, Mar 11, 2005 at 07:34:46PM +1100, Peter Chubb wrote: >> >>>>> "Greg" == Greg KH writes: >> Greg> On Fri, Mar 11, 2005 at 02:37:17PM +1100, Peter Chubb wrote: >> >> +/* + * The PCI subsystem is implemented as yet-another pseudo >> >> filesystem, + * albeit one that is never mounted. + * This is >> its >> magic number. + */ +#define USR_PCI_MAGIC (0x12345678) >> Greg> If you make it a real, mountable filesystem, then you don't need Greg> to have any of your new syscalls, right? Why not just do that Greg> instead? >> >> >> The only call that would go is usr_pci_open() -- you'd still need >> usr_pci_map() Greg> see mmap(2) mmap maps a file's contents into your own virtual memory. usr_pci_map maps part of your own virtual memory into pci bus space for a particular device (using the IOMMU if your machine has one), and returns a scatterlist of bus addresses to hand to the device. Different semantics entirely. Greg> In fact, both of the above can be done today from /proc/bus/pci/ Greg> right? Nope. -- Dr Peter Chubb http://www.gelato.unsw.edu.au peterc AT gelato.unsw.edu.au The technical we do immediately, the political takes *forever* - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/