From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Fri, 04 Oct 2002 14:39:27 +0200 (CEST) Received: from p508B493B.dip.t-dialin.net ([80.139.73.59]:43681 "EHLO dea.linux-mips.net") by linux-mips.org with ESMTP id ; Fri, 4 Oct 2002 14:39:26 +0200 Received: (from ralf@localhost) by dea.linux-mips.net (8.11.6/8.11.6) id g94CcjF15967; Fri, 4 Oct 2002 14:38:45 +0200 Date: Fri, 4 Oct 2002 14:38:45 +0200 From: Ralf Baechle To: Hartvig Ekner Cc: Dominic Sweetman , Carsten Langgaard , linux-mips@linux-mips.org Subject: Re: Promblem with PREF (prefetching) in memcpy Message-ID: <20021004143845.A15883@linux-mips.org> References: <200210041153.MAA12052@mudchute.algor.co.uk> <200210041233.g94CXrQ29071@copfs01.mips.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <200210041233.g94CXrQ29071@copfs01.mips.com>; from hartvige@mips.com on Fri, Oct 04, 2002 at 02:33:53PM +0200 Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 361 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ralf@linux-mips.org Precedence: bulk X-list: linux-mips On Fri, Oct 04, 2002 at 02:33:53PM +0200, Hartvig Ekner wrote: > this problem occurs in kernel space (kseg0), not user space. In user space > there is no problem due to the TLB "protection" of PREFs going outside the > process working set, but that doesn't help in kernel mode. Assume a userspace device driver having some hardware mapped immediately following a ordinary memory mapping. In that case it would be possible for prefetch to run from the one into the next mapping - boom. Ralf