Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262613AbVAKCJi (ORCPT ); Mon, 10 Jan 2005 21:09:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262595AbVAKCGu (ORCPT ); Mon, 10 Jan 2005 21:06:50 -0500 Received: from holomorphy.com ([207.189.100.168]:28302 "EHLO holomorphy.com") by vger.kernel.org with ESMTP id S262608AbVAKCGC (ORCPT ); Mon, 10 Jan 2005 21:06:02 -0500 Date: Mon, 10 Jan 2005 18:05:50 -0800 From: William Lee Irwin III To: Linus Torvalds Cc: "Randy.Dunlap" , Dave , linux-kernel@vger.kernel.org, smaurer@teja.com, linux@arm.linux.org.uk, dsaxena@plexity.net, drew.moseley@intel.com Subject: Re: clean way to support >32bit addr on 32bit CPU Message-ID: <20050111020550.GE2696@holomorphy.com> References: <8746466a050110153479954fd2@mail.gmail.com> <41E31D95.50205@osdl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: The Domain of Holomorphy User-Agent: Mutt/1.5.6+20040722i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1818 Lines: 36 On Mon, Jan 10, 2005 at 05:30:25PM -0800, Linus Torvalds wrote: > I don't think ioaddr_t needs to match resources. None of the IO accessor > functions take "u64"s anyway - and aren't likely to do so in the future > either - so "unsigned long" should be good enough. > Having u64 for resource handling is mainly an issue for RAM and > memory-mapped IO (right now the 32-bit limit means that we throw away > information about stuff above the 4GB mark from the e820 interfaces on > x86, for example - that _happens_ to work because we never see anything > but RAM there anyway, but it means that /proc/iomem doesn't show all of > the system RAM, and it does mean that our resource management doesn't > actually handle 64-bit addresses correctly. > See drivers/pci/probe.c for the result: > "PCI: Unable to handle 64-bit address for device xxxx" > (and I do not actually think this has _ever_ happened in real life, which > makes me suspect that Windows doesn't handle them either - but it > inevitably will happen some day). I have a vague recollection of seeing a report of an ia32 device and/or machine with this property from John Fusco but am having a tough time searching the archives properly for it. I do recall it being around the time the remap_pfn_range() work was started, and I also claimed it as one of the motivators of it in one of my posts. I'm unaware of whether there are more general resources in John Fusco's situation. My follow-ups began with: Message-ID: <20040924021735.GL9106@holomorphy.com> References: <41535AAE.6090700@yahoo.com> -- wli - 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/