From owner-freebsd-current@FreeBSD.ORG Wed Aug 20 10:29:34 2003 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id E776316A4BF for ; Wed, 20 Aug 2003 10:29:34 -0700 (PDT) Received: from godel.mtl.distributel.net (nat.MTL.distributel.NET [66.38.181.24]) by mx1.FreeBSD.org (Postfix) with ESMTP id CA85343FB1 for ; Wed, 20 Aug 2003 10:29:33 -0700 (PDT) (envelope-from bmilekic@technokratis.com) Received: from godel.mtl.distributel.net (localhost [127.0.0.1]) h7KDTsr2075821; Wed, 20 Aug 2003 13:29:54 GMT (envelope-from bmilekic@technokratis.com) Received: (from bmilekic@localhost) by godel.mtl.distributel.net (8.12.9/8.12.9/Submit) id h7KDTs99075820; Wed, 20 Aug 2003 13:29:54 GMT X-Authentication-Warning: godel.mtl.distributel.net: bmilekic set sender to bmilekic@technokratis.com using -f Date: Wed, 20 Aug 2003 13:29:54 +0000 From: Bosko Milekic To: Nate Lawson Message-ID: <20030820132954.GA75697@technokratis.com> References: <20030820100550.X20538@root.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030820100550.X20538@root.org> User-Agent: Mutt/1.4.1i cc: current@freebsd.org Subject: Re: 5.1, Data Corruption, Intel, Oh my! [patch] X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 20 Aug 2003 17:29:35 -0000 On Wed, Aug 20, 2003 at 10:09:34AM -0700, Nate Lawson wrote: > I haven't had time to test your patch unfortunately but just wanted to let > you know of a corner case to be aware of. To suspend, ACPI maps in and > identity page table (phys == virt) and switches to real mode. I'm not > sure if your patches change the ability to access the first 1M or change > the way such a mapping would be done, but it would be useful if you > thought about this. The code is in /sys/i386/acpica/acpi_wakeup.c: > acpi_sleep_machdep(). A P==V mapping is also done during the startup of the APs on SMP. There should not be a problem. Also, this change loads the kernel at 0x400000 (so at the next 4M) just to be sure to not map that first 4M region in a 4M page, in particular to prevent from exposing holes in the region via a 4M page at any time. It should be noted that the changes leave the page tables describing the kernel with 4K-page ptes lying around in order to accomodate the P==V switchover in mp_machdep.c, so the legacy 4K page tables are still around, should they be required in a different mapping (like the mp_machdep one). In any case, it would still be nice if the acpi users (for whom acpi works for the most part) could give the patch a try as well (I have a decent-sized list of testers but would nonetheless welcome/appreciate more). > Thanks, > -Nate Cheers, -- Bosko Milekic * bmilekic@technokratis.com * bmilekic@FreeBSD.org TECHNOkRATIS Consulting Services * http://www.technokratis.com/