Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762015AbYF3RnS (ORCPT ); Mon, 30 Jun 2008 13:43:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752072AbYF3RnJ (ORCPT ); Mon, 30 Jun 2008 13:43:09 -0400 Received: from gw.goop.org ([64.81.55.164]:44727 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752031AbYF3RnH (ORCPT ); Mon, 30 Jun 2008 13:43:07 -0400 Message-ID: <48691B25.5040602@goop.org> Date: Mon, 30 Jun 2008 10:43:01 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: Mike Travis CC: "Eric W. Biederman" , Christoph Lameter , Linux Kernel Mailing List , "H. Peter Anvin" Subject: Re: [crash, bisected] Re: [PATCH 3/4] x86_64: Fold pda into per cpu area References: <20080604003018.538497000@polaris-admin.engr.sgi.com> <20080605102222.GA21319@elte.hu> <484EF29C.7080100@sgi.com> <485947A8.8060801@goop.org> <4859511E.5050605@sgi.com> <48596315.6020104@goop.org> <48596893.4040908@sgi.com> <485AADAC.3070301@sgi.com> <485AB78B.5090904@goop.org> <485AC120.6010202@sgi.com> <485AC5D4.6040302@goop.org> <485ACA8F.10006@sgi.com> <485ACD92.8050109@sgi.com> <485AD138.4010404@goop.org> <485ADA12.5010505@sgi.com> <485ADC73.60009@goop.org> <485BDB04.4090709@sgi.com> <485BE80E.10209@goop.org> <485BF8F5.6010802@goop.org> <485BFFC5.6020404@sgi.com> <486912C4.8070705@sgi.com> In-Reply-To: <486912C4.8070705@sgi.com> X-Enigmail-Version: 0.95.6 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 Content-Length: 1582 Lines: 45 Mike Travis wrote: > Eric W. Biederman wrote: > >> Mike Travis writes: >> > ... > >>> Can we generate a new symbol which would account for LOAD_OFFSET? >>> >> Ouch. Absolute symbols indeed. On the 32bit kernel that may play havoc >> with the relocatable kernel, although we have had similar absolute logic >> for the last year. With __per_cpu_start and __per_cpu_end so it may >> not be a problem. >> >> To initialize the percpu data you do want to talk to the virtual address >> at __per_coup_load. But it is absolute Ugh. >> >> It might be worth saying something like. >> .data.percpu.start : AT(.data.percpu.dummy - LOAD_OFFSET) { >> DATA(0) >> . = ALIGN(align); >> __per_cpu_load = . ; >> } >> To make __per_cpu_load a relative symbol. ld has a bad habit of taking >> symbols out of empty sections and making them absolute. Which is why >> I added the DATA(0). >> >> Still I don't think that would be the 64bit problem. >> >> Eric >> > > FYI, I did try this out and it caused the bootloader to scramble the > loaded data. The first corruption I found was the .x86cpuvendor.init > section contained all zeroes. Well, that's what appeared to be happening with the pre-initialized GDT as well, so I'm not sure that's a new symptom. J -- 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/