Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752151AbaFFUpR (ORCPT ); Fri, 6 Jun 2014 16:45:17 -0400 Received: from mail-ig0-f182.google.com ([209.85.213.182]:59169 "EHLO mail-ig0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751969AbaFFUpP convert rfc822-to-8bit (ORCPT ); Fri, 6 Jun 2014 16:45:15 -0400 MIME-Version: 1.0 In-Reply-To: References: <53920B05.9010602@mit.edu> Date: Fri, 6 Jun 2014 13:45:14 -0700 Message-ID: Subject: Re: "." in vmlinux.lds.S From: =?UTF-8?B?SMOhbiBTaMSbbiAo5rKI5ra1KQ==?= To: Andy Lutomirski Cc: "linux-kernel@vger.kernel.org" , X86 ML Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Andy, this changes "Ndx" field for the symbol. For example, one of the symbol '__end_rodata_hpage_align' in symtab, the contents changed from 50206: ffffffff81800000 0 NOTYPE GLOBAL DEFAULT ABS __end_rodata_hpage_align which is correct, to 50206: ffffffff81800000 0 NOTYPE GLOBAL DEFAULT 25 __end_rodata_hpage_align (25 is the index to section '.data') which is wrong. Han On Fri, Jun 6, 2014 at 12:08 PM, Andy Lutomirski wrote: > On Fri, Jun 6, 2014 at 11:53 AM, Hán Shěn (沈涵) wrote: >> Yeah, the symbol "__end_rodata_hpage_align" is defined as absolute in >> older binutils, the newer binutils making it relative seems >> meaningless in this context. > > What I mean is: what actually changes in the linker output when the > symbol is relative? > > --Andy > >> >> On Fri, Jun 6, 2014 at 11:40 AM, Andy Lutomirski wrote: >>> On 06/06/2014 10:08 AM, Hán Shěn (沈涵) wrote: >>>> A gentle ping? >>>> >>>> On Tue, Jun 3, 2014 at 2:46 PM, Hán Shěn (沈涵) wrote: >>>>> Hi we are trying to boot up a x86_64 chrome book using binutils 2.24 and >>>>> kernel 3.8, but failed. >>>>> >>>>> After some triage work, we found that a 2-year-old binutil CL changed the >>>>> interpretation of "." in linker script （short story: absolute -> relative, >>>>> long story: https://sourceware.org/ml/binutils/2012-06/msg00155.html). >>>>> >>>>> After some further work, we are able to boot the kernel with a kernel patch >>>>> pasted at EOM. I am curious, why the upstream kernel is never hit by this >>>>> behavior? We enabled "CONFIG_DEBUG_RODATA", so we were hit, is this some >>>>> macro not usually turned on? >>> >>> What does a section-relative symbol do? >>> >>> --Andy >> >> >> >> -- >> Han Shen | Software Engineer | shenhan@google.com | +1-650-440-3330 > > > > -- > Andy Lutomirski > AMA Capital Management, LLC -- Han Shen | Software Engineer | shenhan@google.com | +1-650-440-3330 -- 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/