Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752524AbXBSAWJ (ORCPT ); Sun, 18 Feb 2007 19:22:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752562AbXBSAWJ (ORCPT ); Sun, 18 Feb 2007 19:22:09 -0500 Received: from ozlabs.org ([203.10.76.45]:59128 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752524AbXBSAWH (ORCPT ); Sun, 18 Feb 2007 19:22:07 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <17880.60841.973258.612628@cargo.ozlabs.ibm.com> Date: Mon, 19 Feb 2007 11:22:01 +1100 From: Paul Mackerras To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Linus Torvalds , Arjan van de Ven , Christoph Hellwig , Andrew Morton , Alan Cox , Ulrich Drepper , Zach Brown , Evgeniy Polyakov , "David S. Miller" , Benjamin LaHaise , Suparna Bhattacharya , Davide Libenzi , Thomas Gleixner Subject: Re: [patch 02/11] syslets: add syslet.h include file, user API/ABI definitions In-Reply-To: <20070213142024.GC638@elte.hu> References: <20060529212109.GA2058@elte.hu> <20070213142024.GC638@elte.hu> X-Mailer: VM 7.19 under Emacs 21.4.1 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1182 Lines: 34 Ingo Molnar writes: > add include/linux/syslet.h which contains the user-space API/ABI > declarations. Add the new header to include/linux/Kbuild as well. > +struct syslet_uatom { > + unsigned long flags; > + unsigned long nr; > + long __user *ret_ptr; > + struct syslet_uatom __user *next; > + unsigned long __user *arg_ptr[6]; > + /* > + * User-space can put anything in here, kernel will not > + * touch it: > + */ > + void __user *private; > +}; This structure, with its unsigned longs and pointers, is going to create enormous headaches for 32-bit processes on 64-bit machines as far as I can see---and on ppc64 machines, almost all processes are 32-bit, since there is no inherent speed penalty for running in 32-bit mode, and some space savings. Have you thought about how you will handle compatibility for 32-bit processes? The issue will arise for x86_64 and ia64 (among others) too, I would think. Paul. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/