From owner-freebsd-hackers Fri Nov 14 21:09:52 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id VAA00521 for hackers-outgoing; Fri, 14 Nov 1997 21:09:52 -0800 (PST) (envelope-from owner-freebsd-hackers) Received: from sumatra.americantv.com (sumatra.americantv.com [207.170.17.37]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id VAA00514 for ; Fri, 14 Nov 1997 21:09:48 -0800 (PST) (envelope-from jlemon@americantv.com) Received: from right.PCS (right.PCS [148.105.10.31]) by sumatra.americantv.com (8.8.5/8.8.5) with ESMTP id XAA11803; Fri, 14 Nov 1997 23:09:46 -0600 (CST) Received: (from jlemon@localhost) by right.PCS (8.6.13/8.6.4) id XAA11123; Fri, 14 Nov 1997 23:09:15 -0600 Message-ID: <19971114230915.12485@right.PCS> Date: Fri, 14 Nov 1997 23:09:15 -0600 From: Jonathan Lemon To: Joe Eykholt Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: FreeBSD Pentium Bug fix (proposed) References: <199711150115.RAA18627@hub.freebsd.org> <346D17BA.1B37ADEA@ipsilon.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.61.1 In-Reply-To: <346D17BA.1B37ADEA@ipsilon.com>; from Joe Eykholt on Nov 11, 1997 at 07:32:10PM -0800 Sender: owner-freebsd-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk On Nov 11, 1997 at 07:32:10PM -0800, Joe Eykholt wrote: > One point, though. The segment length is at least one byte > since the limit in the descriptor is the last valid offset > in the segment, not the length. That means that the address might > be referenced. The granularity should be 0 for bytes. The address within in the segment is specified by the vector address contained within the IDT descriptor, so we don't have to worry about that. > so another, guaranteed-invalid address might be better, or you might > leave the P bit off in that segment or (better) in the > IDT entry 6 descriptor, causing a segment-not-present fault. > (I haven't tried any of this). Leaving the `P'resent bit off does generate a segment-not-present fault. Unfortunately, this is of lower priority than a illegal instruction fault, and doesn't work. (This was the first thing I tried) -- Jonathan