From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 10 Jan 2001 18:57:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 10 Jan 2001 18:57:30 -0500 Received: from kleopatra.acc.umu.se ([130.239.18.150]:28397 "EHLO kleopatra.acc.umu.se") by vger.kernel.org with ESMTP id ; Wed, 10 Jan 2001 18:57:15 -0500 Date: Thu, 11 Jan 2001 00:56:57 +0100 From: David Weinehall To: Alan Cox Cc: Linus Torvalds , "Eric W. Biederman" , Andrea Arcangeli , David Woodhouse , Zlatko Calusic , Rik van Riel , linux-kernel@vger.kernel.org Subject: Re: Subtle MM bug Message-ID: <20010111005657.B2243@khan.acc.umu.se> In-Reply-To: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.4i In-Reply-To: ; from alan@lxorguk.ukuu.org.uk on Wed, Jan 10, 2001 at 07:36:43PM +0000 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 10, 2001 at 07:36:43PM +0000, Alan Cox wrote: > > I looked at it a year or two ago myself, and came to the conclusion that I > > don't want to blow up our page table size by a factor of three or more, so > > I'm not personally interested any more. Maybe somebody else comes up with > > a better way to do it, or with a really compelling reason to. > > There is only one reason I know for reverse page tables. That is ARM2/ARM3 > support - which is still not fully merged because of this issue > > The MMU on these systems is a CAM, and the mmu table is thus backwards to > convention. (It also means you can notionally map two physical addresses to > one virtual but thats undefined in the implementation ;)) Are there any other (not yet supported) platforms with similar (or other unrelated, but hard to support because of the current architecture of the kernel) problems? (No, I have no secret trumps up my sleeve, I'm just curious.) /David _ _ // David Weinehall /> Northern lights wander \\ // Project MCA Linux hacker // Dance across the winter sky // \> http://www.acc.umu.se/~tao/