From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750980AbWFFKmd (ORCPT ); Tue, 6 Jun 2006 06:42:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751088AbWFFKmd (ORCPT ); Tue, 6 Jun 2006 06:42:33 -0400 Received: from ns2.suse.de ([195.135.220.15]:6279 "EHLO mx2.suse.de") by vger.kernel.org with ESMTP id S1750980AbWFFKmc (ORCPT ); Tue, 6 Jun 2006 06:42:32 -0400 To: Thomas Glanzmann Cc: linux-kernel@vger.kernel.org Subject: Re: AMD64: 64 bit kernel 32 bit userland - some pending questions References: <20060606093456.GL4552@cip.informatik.uni-erlangen.de> From: Andi Kleen Date: 06 Jun 2006 12:42:30 +0200 In-Reply-To: <20060606093456.GL4552@cip.informatik.uni-erlangen.de> Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Thomas Glanzmann writes: > Hello everyone, > I would like to use an AMD64 Opteron System with a 64 bit Linux Kernel, > but a 32 bit userland (Debian Sarge). I have a few questions about this: The main caveat is that iptables and ipsec need 64bit executables to be set up. The rest should work. > > - Is it possible to give the userland 3Gbyte virtual address > space (default for 2.4 and 2.6). The default is 4GB, but you can get 3GB by running it under linux32 --3gb > But give the Kernel a 64 bit > virtual address space so that I get more than 1 Gbyte physical > Memory into LOWMEM - say I want 8 Gbyte - without using HIGHMEM The 64bit kernel never uses highmem. > - What is the easiest way to build a 64 bit kernel on a 32 bit > Debian sarge. Are there crosscompiler packages available? Are > there any guides on this? If all fails you can get a cross compiler from crosstool. Then normal kernel compilation command with make ... ARCH=x86_64 CROSS_COMPILE=x86_64-linux- -Andi