From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934870Ab3BNTV0 (ORCPT ); Thu, 14 Feb 2013 14:21:26 -0500 Received: from terminus.zytor.com ([198.137.202.10]:55480 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934815Ab3BNTVZ (ORCPT ); Thu, 14 Feb 2013 14:21:25 -0500 Message-ID: <511D3928.80402@zytor.com> Date: Thu, 14 Feb 2013 11:21:12 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: Oleg Nesterov CC: Denys Vlasenko , linux-kernel@vger.kernel.org, Andi Kleen Subject: Re: [PATCH] x86: make PTRACE_GETREGSET return 32-bit regs if 64-bit process entered kernel with int 80 References: <511CE3D0.8000308@redhat.com> <20130214150046.GA30543@redhat.com> <511D2779.7040504@zytor.com> <20130214191842.GA11620@redhat.com> In-Reply-To: <20130214191842.GA11620@redhat.com> X-Enigmail-Version: 1.5 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/14/2013 11:18 AM, Oleg Nesterov wrote: > On 02/14, H. Peter Anvin wrote: >> >> On 02/14/2013 07:00 AM, Oleg Nesterov wrote: >>> On 02/14, Denys Vlasenko wrote: >>>> >>>> Determining personality of a ptraced process is a murky area. >>>> On x86, for years strace was looking at segment selectors, >>>> which is conceptually wrong: see, for example, >>>> https://lkml.org/lkml/2012/1/18/320 >>>> >> >> One proposal that keeps being on the table is to export a regset with >> metadatam, including process mode at launch (i386, x86-64, x32). > > Yes... but if this metadata includes TS_COMPAT-is-set, then strace should > do PTRACE_GETREGSET(REGSET_META) + PTRACE_GETREGSET(REGSET_GENERAL) every > time. Or REGSET_META should include META+GENERAL. > > IOW, it is not clear to me what this "meta" should actually report. > That is one of the things that needs to be nailed down. In particular, what are the things people need. -hpa