From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Thu, 03 Feb 2005 12:30:04 +0000 (GMT) Received: from p3EE07C05.dip.t-dialin.net ([IPv6:::ffff:62.224.124.5]:39794 "EHLO mail.linux-mips.net") by linux-mips.org with ESMTP id ; Thu, 3 Feb 2005 12:29:50 +0000 Received: from fluff.linux-mips.net (localhost.localdomain [127.0.0.1]) by mail.linux-mips.net (8.13.1/8.13.1) with ESMTP id j13CTmxN008642; Thu, 3 Feb 2005 13:29:48 +0100 Received: (from ralf@localhost) by fluff.linux-mips.net (8.13.1/8.13.1/Submit) id j13CThwR008641; Thu, 3 Feb 2005 13:29:44 +0100 Date: Thu, 3 Feb 2005 13:29:43 +0100 From: Ralf Baechle To: "Nori, Soma Sekhar" Cc: linux-mips@linux-mips.org Subject: Re: Dealing with RAM not starting at 0x00000000 Message-ID: <20050203122943.GA8509@linux-mips.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 7125 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ralf@linux-mips.org Precedence: bulk X-list: linux-mips On Tue, Feb 01, 2005 at 03:06:29PM +0530, Nori, Soma Sekhar wrote: > I am working towards porting 2.6.10 kernel on a mips 4kec based board > which has physical memory starting at 0x14000000. > What is the best way to overcome the "hole" from 0x00000000 to > 0x14000000 without incuring a huge memory overhead. > (For exception handling there is 4k of RAM kept at 0x00000000 also - but > I guess linux paging need need not be aware of this small RAM) You can set PAGE_OFFSET to 0x94000000. If you do this you're probably going to run into a few bugs where PAGE_OFFSET is assumed to be KSEG0, that is 0x80000000. Nothing dramatic though. Ralf