From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755770AbYGJIUV (ORCPT ); Thu, 10 Jul 2008 04:20:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751672AbYGJIUF (ORCPT ); Thu, 10 Jul 2008 04:20:05 -0400 Received: from fg-out-1718.google.com ([72.14.220.152]:53202 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750980AbYGJIUD (ORCPT ); Thu, 10 Jul 2008 04:20:03 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:x-enigmail-version:content-type :content-transfer-encoding; b=cDKSlk341JqA1QZZrJoDvp5WoKHDKyjyFAXJyNEDqffO8RFtwRJR0Qj4am0B9JtgFE PHbyb60/7Xh6YLrEIpNTJXkhuSWer5AaEEII/MNXSjAgwNwTFzViDWeiw4smlTuS/My/ v6a9+10KvnrTz4p+QyS8ahoqJ3TGstJzFKa54= Message-ID: <4875C5C2.6010703@gmail.com> Date: Thu, 10 Jul 2008 10:18:10 +0200 From: Jiri Slaby User-Agent: Thunderbird 2.0.0.14 (X11/20080421) MIME-Version: 1.0 To: Matthias Schniedermeyer CC: "Shaun R." , linux-kernel@vger.kernel.org Subject: Re: 64bit kernel, 32bit OS? References: <20080710072037.GA10883@citd.de> In-Reply-To: <20080710072037.GA10883@citd.de> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/10/2008 09:20 AM, Matthias Schniedermeyer wrote: > On 09.07.2008 17:16, Shaun R. wrote: >> If i where to run a 32bit OS on a 64bit kernel would there be any >> problems with that? I'm not trying to convert the OS to 64bit, just >> would rather not have to build multiple kernels if i dont have too. I'm >> talking x86_32 and x86_64 btw too. > > I guess you mean 32bit userspace with a 64bit kernel. > > And that's no problem as long as "CONFIG_IA32_EMULATION" is set > The option is in the menu: Executable file formats / Emulations > and is called: IA32 Emulation Just my $.02. I do this configuration for years on some machines. The only problem I've ever met is that some drivers are broken to support this configuration, some ioctls or mmap structures simply binary differs on 32 and 64-bit (due to different alignment and members size) and the driver can't cope with that -- doesn't define ioctls independently on arch or let the structures unaligned. So make sure you won't use any proprietary blob which can't handle this (e.g. nvidia is OK).