From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755248AbYDJBOn (ORCPT ); Wed, 9 Apr 2008 21:14:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752898AbYDJBOe (ORCPT ); Wed, 9 Apr 2008 21:14:34 -0400 Received: from terminus.zytor.com ([198.137.202.10]:49539 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752597AbYDJBOe (ORCPT ); Wed, 9 Apr 2008 21:14:34 -0400 Message-ID: <47FD6921.6090408@zytor.com> Date: Wed, 09 Apr 2008 18:10:57 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.12 (X11/20080226) MIME-Version: 1.0 To: sukadev@us.ibm.com CC: Andrew Morton , clg@fr.ibm.com, serue@us.ibm.com, "David C. Hansen" , Pavel Emelyanov , Containers , linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/3] clone64() and unshare64() system calls References: <20080409222611.GA28087@us.ibm.com> <47FD5899.2040206@zytor.com> <20080410010717.GA28477@us.ibm.com> In-Reply-To: <20080410010717.GA28477@us.ibm.com> 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 sukadev@us.ibm.com wrote: >> >> If you're going to make it a 64-bit pass it in as a 64-bit number, instead >> of breaking it into two numbers. > > Maybe I am missing your point. The glibc interface could take a 64bit > parameter, but don't we need to pass 32-bit values into the system call > on 32 bit systems ? Not as such, no. The ABI handles that. To make the ABI clean on some architectures, it's good to consider a 64-bit value only in positions where they map to an even:odd register pair once slotted in. > Yes, this was discussed before in the context of Pavel Emelyanov's patch > > http://lkml.org/lkml/2008/1/16/109 > > along with sys_indirect(). While there was no consensus, it looked like > adding a new system call was better than open ended interfaces. That's not really an open-ended interface, it's just an expandable bitmap. -hpa