From owner-freebsd-hackers Sun May 17 15:20:53 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id PAA01409 for freebsd-hackers-outgoing; Sun, 17 May 1998 15:20:53 -0700 (PDT) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from gatekeeper.alcatel.com.au (gatekeeper.alcatel.com.au [203.17.66.1]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id PAA01279 for ; Sun, 17 May 1998 15:20:11 -0700 (PDT) (envelope-from peter.jeremy@alcatel.com.au) Received: from mfg1.cim.alcatel.com.au ("port 3812"@[139.188.23.1]) by gatekeeper.alcatel.com.au (PMDF V5.1-7 #U2695) with ESMTP id <01IX67IIKH8G000M5H@gatekeeper.alcatel.com.au> for freebsd-hackers@freebsd.org; Mon, 18 May 1998 08:19:28 +1000 Received: from gsms01.alcatel.com.au by cim.alcatel.com.au (PMDF V5.1-10 #U2695) with ESMTP id <01IX67IC9WEOB4WSO4@cim.alcatel.com.au> for freebsd-hackers@freebsd.org; Mon, 18 May 1998 08:19:22 +1000 Received: (from jeremyp@localhost) by gsms01.alcatel.com.au (8.8.8/8.7.3) id IAA03007 for freebsd-hackers@freebsd.org; Mon, 18 May 1998 08:18:41 +1000 (EST) Date: Mon, 18 May 1998 08:18:41 +1000 (EST) From: Peter Jeremy Subject: Pentium F00F bug To: freebsd-hackers@FreeBSD.ORG Message-id: <199805172218.IAA03007@gsms01.alcatel.com.au> Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG There's an interesting article on the F00F bug by Robert Collins in May Dr Dobbs Journal. He discusses the adverse impacts of Intel's recommended work-arounds (one of which we use). Robert suggests alternative solutions, which rely on interactions between the bug and the cache, rather than the page fault microcode. These solutions uses the same cross-page IDT alignment as Intel, but mark the first page non-cacheable - either set PTE.PCD=1 or PTE.PWT=1. The major benefit of this approach is that the exception handlers all vector directly to the appropriate interrupt handler - no kludges in the page-fault handler are needed. Has anyone looked into using these work-arounds instead? Peter -- Peter Jeremy (VK2PJ) peter.jeremy@alcatel.com.au Alcatel Australia Limited 41 Mandible St Phone: +61 2 9690 5019 ALEXANDRIA NSW 2015 Fax: +61 2 9690 5247 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message