From owner-freebsd-hackers Fri Nov 1 13:03:05 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id NAA09160 for hackers-outgoing; Fri, 1 Nov 1996 13:03:05 -0800 (PST) Received: from mail13.digital.com (mail13.digital.com [192.208.46.30]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id NAA09138 for ; Fri, 1 Nov 1996 13:02:55 -0800 (PST) Received: from muggsy.lkg.dec.com by mail13.digital.com (8.7.5/UNX 1.5/1.0/WV) id PAA04999; Fri, 1 Nov 1996 15:50:13 -0500 (EST) Received: from whydos.lkg.dec.com by muggsy.lkg.dec.com (5.65/DEC-Ultrix/4.3) with SMTP id AA26480; Fri, 1 Nov 1996 15:49:31 -0500 Received: from localhost.lkg.dec.com (localhost.lkg.dec.com [127.0.0.1]) by whydos.lkg.dec.com (8.6.12/8.6.12) with SMTP id QAA14425; Fri, 1 Nov 1996 16:56:05 GMT Message-Id: <199611011656.QAA14425@whydos.lkg.dec.com> X-Authentication-Warning: whydos.lkg.dec.com: Host localhost.lkg.dec.com didn't use HELO protocol X-Mailer: exmh version 1.6.5 12/11/95 To: Terry Lambert Cc: msmith@atrad.adelaide.edu.au (Michael Smith), freebsd-hackers@freefall.freebsd.org Subject: Re: VM answer requested In-Reply-To: Your message of "Fri, 01 Nov 1996 11:42:21 MST." <199611011842.LAA28151@phaeton.artisoft.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Fri, 01 Nov 1996 16:56:00 +0000 From: Matt Thomas Sender: owner-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk > What about the aligned access bit in recent Intel processors? > > I'd like to be able to turn on the bit so that I get a fault (and it > kills the offending process) when an unaligned access occurs. > > I'd also like to get kernel faults if this happens in the kernel > (it is my opinion that it should never be allowed to happen in the > kernel, and there should be a sanitization pass to insure it). Don't use the de driver then. Because of a misfeature in the 21x4x chips, the Ethernet payload (the stuff after the header) is not longword aligned). Having the processor deal with unaligned data is much faster than copying the data so that it is aligned. -- Matt Thomas Internet: matt@3am-software.com 3am Software Foundry WWW URL: http://www.3am-software.com/bio/matt.html Westford, MA Disclaimer: I disavow all knowledge of this message