From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932140AbVHHRgB (ORCPT ); Mon, 8 Aug 2005 13:36:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932144AbVHHRgB (ORCPT ); Mon, 8 Aug 2005 13:36:01 -0400 Received: from gateway-1237.mvista.com ([12.44.186.158]:56059 "EHLO av.mvista.com") by vger.kernel.org with ESMTP id S932140AbVHHRgA (ORCPT ); Mon, 8 Aug 2005 13:36:00 -0400 Message-ID: <42F797F7.1020806@mvista.com> Date: Mon, 08 Aug 2005 10:35:51 -0700 From: Dave Jiang Organization: MontaVista Software, Inc. User-Agent: Mozilla Thunderbird 1.0.6 (X11/20050716) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Jan Engelhardt CC: Andi Kleen , linux-kernel@vger.kernel.org Subject: Re: x86_64 frame pointer via thread context References: <42F3EC97.2060906@mvista.com.suse.lists.linux.kernel> <42F79615.3000108@mvista.com> In-Reply-To: <42F79615.3000108@mvista.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Dave Jiang wrote: > Jan Engelhardt wrote: > >>>> Am I doing something wrong, or is this intended to be this way on >>>> x86_64, or is something incorrect in the kernel? This method works >>>> fine on i386. Thanks for any help! >>> >>> >>> I just tested your program on SLES9 with updated kernel and RBP >>> looks correct to me. Probably something is wrong with your user space >>> includes or your compiler. >> >> >> >> Note that there is -fomit-frame-pointer which might give different >> results than without the option (or explicitly -fno-omit-frame-pointer). >> >> >> Jan Engelhardt > > > I had somebody else test it on FC4 and he observed the same issue. It > may be timing sensitive? Both platforms tested are em64t based so I'm > not sure if on amd64 platforms it varies or not..... > > And you definitely have to include the -fno-omit-frame-pointer. x86_64 > gcc by default has -fomit-frame-pointer on and without explicitly > stating that you want frame pointer you won't get it in rBP. > > It is possible that userspace or toolchain may be suspect, However, why > is the value bad in kernel space when rBP from pt_regs is dumped? > > One additional note. The app dumps the rBP for two threads. One looks okay, and the other gives 0xffffffff. -- Dave ------------------------------------------------------ Dave Jiang Software Engineer Phone: (480) 517-0372 MontaVista Software, Inc. Fax: (480) 517-0262 2141 E Broadway Rd, St 108 Web: www.mvista.com Tempe, AZ 85282 mailto:djiang@mvista.com ------------------------------------------------------