From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161014AbWJFOor (ORCPT ); Fri, 6 Oct 2006 10:44:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161018AbWJFOor (ORCPT ); Fri, 6 Oct 2006 10:44:47 -0400 Received: from static-ip-62-75-166-246.inaddr.intergenia.de ([62.75.166.246]:55969 "EHLO bu3sch.de") by vger.kernel.org with ESMTP id S1161014AbWJFOoq (ORCPT ); Fri, 6 Oct 2006 10:44:46 -0400 From: Michael Buesch To: Alan Cox Subject: Re: Really good idea to allow mmap(0, FIXED)? Date: Fri, 6 Oct 2006 16:44:32 +0200 User-Agent: KMail/1.9.4 References: <200610052059.11714.mb@bu3sch.de> <1160085480.1607.32.camel@localhost.localdomain> In-Reply-To: <1160085480.1607.32.camel@localhost.localdomain> Cc: linux-kernel MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200610061644.33267.mb@bu3sch.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 05 October 2006 23:58, Alan Cox wrote: > Ar Iau, 2006-10-05 am 20:59 +0200, ysgrifennodd Michael Buesch: > > Is is really a good idea to allow processes to remap something > > to address 0? > > It is very useful indeed. Consider for example dosemu. Ok, good point. > > Besides that, I currently don't see a valid reason to mmap address 0. > > > > Comments? > > User zero is not neccessarily mapped at kernel zero so your argument > isn't portable either. Eh, so what about the following. We _have_ arches which map user zero to kernel zero. What about specialcasing that on a per-arch case. So remapping user zero to something else in kernel. -- Greetings Michael.