From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264424AbUEaNfX (ORCPT ); Mon, 31 May 2004 09:35:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264625AbUEaNfW (ORCPT ); Mon, 31 May 2004 09:35:22 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.31.123]:47810 "EHLO atrey.karlin.mff.cuni.cz") by vger.kernel.org with ESMTP id S264424AbUEaNfH (ORCPT ); Mon, 31 May 2004 09:35:07 -0400 Date: Thu, 27 May 2004 23:03:46 +0200 From: Pavel Machek To: Herbert Xu Cc: Brian Gerst , willy@w.ods.org, arjanv@redhat.com, hch@lst.de, akpm@osdl.org, linux-kernel@vger.kernel.org Subject: Re: i486 emu in mainline? Message-ID: <20040527210346.GC997@openzaurus.ucw.cz> References: <40B0DB49.3090308@quark.didntduck.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.3.27i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > >> It was intentional for speed purpose. The areas are checked once with > >> verify_area() when we need to access memory, then data is copied directly > >> from/to memory. I don't think there's any risk, but I can be wrong. > > > > Which will break with 4G/4G. You must use at least __get_user(). > > A 386 with a 4G/4G split, I'd like to see that. I believe you could... 1) some 586 class machines do not know 486 opcodes 2) this is for rescue kernel. If you want to be able to rescue 64GB machine *and* rescue 486 too, this+4G/4G is right choice ;-) -- 64 bytes from 195.113.31.123: icmp_seq=28 ttl=51 time=448769.1 ms