From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 19 Feb 2001 17:30:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 19 Feb 2001 17:30:13 -0500 Received: from tomts8.bellnexxia.net ([209.226.175.52]:18655 "EHLO tomts8-srv.bellnexxia.net") by vger.kernel.org with ESMTP id ; Mon, 19 Feb 2001 17:30:03 -0500 Message-ID: <3A919D83.FCC2EF5B@sympatico.ca> Date: Mon, 19 Feb 2001 17:26:11 -0500 From: Jeremy Jackson X-Mailer: Mozilla 4.72 [en] (X11; U; Linux 2.2.14-5.0 i586) X-Accept-Language: en MIME-Version: 1.0 To: "Eric W. Biederman" CC: Jaswinder Singh , peterw@dascom.com.au, "Albert D. Cahalan" , linux-kernel@vger.kernel.org Subject: Re: Kernel executation from ROM In-Reply-To: <01e701c09a2a$21e789a0$bba6b3d0@Toshiba> <3A914E57.9990EB7C@sympatico.ca> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org "Eric W. Biederman" wrote: > No it forbids executing boot roms that way, by a standard pc bios. > The system BIOS in a PC is normally on the ISA bus which is reached > across via the PCI bus with a PCI->ISA bridge. Son of a gun, I missed that... sure enough my PIIX4 docs beside me here show a #BIOSCS pin on the southbridge... Can anybody clarify what this restriction does and doesn't apply to ? The MindShare PCI Arch. book where I got that info from doesn't elaborate that much. > The thing is slow it really doesn't matter, all you need to do is > enable caching on that area of the physical address space. You can't > do this on the alpha currently but only because the alpha sucks that > way. You can on practically everything else. > > As for ROM being slow on x86 you can enable the MTRR to speed things Don't MTRR's just do write combining? > > up. Usually though ROMs are at least as expensive as RAM, so it is > pointless.