Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S271527AbTGQRzI (ORCPT ); Thu, 17 Jul 2003 13:55:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S271525AbTGQRzI (ORCPT ); Thu, 17 Jul 2003 13:55:08 -0400 Received: from palrel12.hp.com ([156.153.255.237]:38889 "EHLO palrel12.hp.com") by vger.kernel.org with ESMTP id S271520AbTGQRzD (ORCPT ); Thu, 17 Jul 2003 13:55:03 -0400 From: David Mosberger MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <16150.58990.896840.65971@napali.hpl.hp.com> Date: Thu, 17 Jul 2003 11:09:50 -0700 To: "Tolentino, Matthew E" Cc: , "Grover, Andrew" , , Subject: RE: [PATCH] remove pa->va->pa conversion for efi.acpi In-Reply-To: References: X-Mailer: VM 7.07 under Emacs 21.2.1 Reply-To: davidm@hpl.hp.com X-URL: http://www.hpl.hp.com/personal/David_Mosberger/ Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1392 Lines: 27 >>>>> On Thu, 17 Jul 2003 10:43:19 -0700, "Tolentino, Matthew E" said: >> Does ACPI really guarantee that the table is never stored at physical >> address 0? If not, then leaving it as a virtual address might be >> safer. (Yes, I know it's very unlikely for today's system, but at >> least on ia64, pfn 0 is normal RAM so it seems at least in principle >> possible to store the ACPI table there). Matthew> No guarantee that I could find...I suppose this is Matthew> technically possible. :) However, considering the ACPI Matthew> routines expect a physical address and thus immediately map Matthew> it to get the descriptor (either directly with virt_to_phys Matthew> or via ioremap), this seems redundant. Given the mapping Matthew> scheme employed, is this still risky? I'd like to reuse Matthew> the same code path for ia32, but don't want to break ia64. Note that I'm only pointing this out because I thought there were some NULL-pointer checks. If it's a physical address, 0 is a valid address. If it's an (identity-mapped) kernel address, NULL-pointer checks are OK. --david - 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/