From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932515Ab2LNWrr (ORCPT ); Fri, 14 Dec 2012 17:47:47 -0500 Received: from terminus.zytor.com ([198.137.202.10]:51381 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932173Ab2LNWrq (ORCPT ); Fri, 14 Dec 2012 17:47:46 -0500 Message-ID: <50CBAC61.5010600@zytor.com> Date: Fri, 14 Dec 2012 14:46:57 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Pavel Emelyanov CC: Andy Lutomirski , aarcange@redhat.com, ak@linux.intel.com, Stefani Seibold , x86@kernel.org, linux-kernel@vger.kernel.org, criu@openvz.org, mingo@redhat.com, john.stultz@linaro.org, tglx@linutronix.de Subject: Re: [CRIU] [PATCH] Add VDSO time function support for x86 32-bit kernel References: <1355343572-23074-1-git-send-email-stefani@seibold.net> <50C9148C.4040308@zytor.com> <1355378005.24283.11.camel@wall-e> <1d3061cb-76d0-4e42-9b75-a975b05384ec@email.android.com> <1355379433.24701.1.camel@wall-e> <1355383038.18653.2.camel@wall-e> <50CA6E4C.6000305@zytor.com> <50CA81A4.9040702@zytor.com> <50CA85BD.7070502@zytor.com> <8c3585bc-fc7d-4826-913c-f4581494d91d@email.android.com> <50CAE485.5020608@parallels.com> In-Reply-To: <50CAE485.5020608@parallels.com> X-Enigmail-Version: 1.4.6 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/14/2012 12:34 AM, Pavel Emelyanov wrote: > On 12/14/2012 06:20 AM, Andy Lutomirski wrote: >> On Thu, Dec 13, 2012 at 6:18 PM, H. Peter Anvin wrote: >>> Wouldn't the vdso get mapped already and could be mremap()'d. If we >> really need more control I'd almost push for a device/filesystem node >> that could be mmapped the usual way. >> >> Hmm. That may work, but it'll still break ABI. I'm not sure that >> criu is stable enough yet that we should care. Criu people? > > It's not yet, but we'd still appreciate the criu-friendly vdso redesign. > >> (In brief summary: how annoying would it be if the vdso was no longer >> just a bunch of constant bytes that lived somewhere?) > > It depends on what vdso is going to be. In the perfect case it should > a) be mremap-able to any address (or be at fixed address _forever_, but > I assume this is not feasible); > b) have entry points at fixed (or somehow movable) places. > > I admit that I didn't understand your question properly, if I did, > please correct me. > Either way... criu on the side, we should proceed with this vdso redesign and get support for the 32-bit entry points including compat mode on x86-64. -hpa