Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752456AbcLMWvK (ORCPT ); Tue, 13 Dec 2016 17:51:10 -0500 Received: from mx2.suse.de ([195.135.220.15]:40011 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751742AbcLMWvH (ORCPT ); Tue, 13 Dec 2016 17:51:07 -0500 Subject: Re: [PATCH] x86/kbuild: enable modversions for symbols exported from asm To: Dodji Seketeli , Nicholas Piggin References: <20161129131922.GA31466@angband.pl> <20161129135118.24696-1-kilobyte@angband.pl> <30bb2db4-47bd-0c35-8328-ef032b551f06@suse.com> <20161129195721.GI2697@decadent.org.uk> <20161201051852.28dc335f@roar.ozlabs.ibm.com> <1480541581.16599.78.camel@decadent.org.uk> <20161201125545.406d092c@roar.ozlabs.ibm.com> <1480559754.16599.92.camel@decadent.org.uk> <20161201143928.07a08348@roar.ozlabs.ibm.com> <6e8cf20b-2d2f-ba1f-e02c-c757d5a25db7@suse.com> <20161209133308.0acbb57a@roar.ozlabs.ibm.com> <1481296893.4509.135.camel@hellion.org.uk> <20161210021529.4a6e684f@roar.ozlabs.ibm.com> <86vaus3eld.fsf@seketeli.org> Cc: Ian Campbell , Ben Hutchings , Linus Torvalds , Adam Borowski , Greg Kroah-Hartman , Linux Kbuild mailing list , Debian kernel maintainers , "linux-arch@vger.kernel.org" , Arnd Bergmann , Ingo Molnar , Linux Kernel Mailing List From: Michal Marek X-Enigmail-Draft-Status: N1110 Message-ID: Date: Tue, 13 Dec 2016 23:51:00 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.0 MIME-Version: 1.0 In-Reply-To: <86vaus3eld.fsf@seketeli.org> 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 Content-Length: 1839 Lines: 42 Dne 9.12.2016 v 23:46 Dodji Seketeli napsal(a): > Hello, > > Nicholas Piggin a écrit: > > [...] > >> That said, a dwarf based checker tool should be able to do as good a job >> (maybe a bit better because report is very informative and it may pick up >> compiler alignments or padding options). > > So, Nicholas was kind enough to send me the two Linux Kernel binaries > that he built with the tiny little interface change that we were > discussing earlier. Here is what the abidiff[1] tools says about that > interface change: > > $ time ~/git/libabigail/kabidiff/build/tools/abidiff vmlinux.abi1.abi vmlinux.abi2.abi > Functions changes summary: 0 Removed, 1 Changed, 0 Added function > Variables changes summary: 0 Removed, 0 Changed, 0 Added variable > > 1 function with some indirect sub-type change: > > [C]'function int foo(blah*)' at memory.c:82:1 has some indirect sub-type changes: > parameter 1 of type 'blah*' has sub-type changes: > in pointed to type 'struct blah' at memory.c:78:1: > type size changed from 32 to 64 bits > 1 data member insertion: > 'int blah::y', at offset 0 (in bits) at memory.c:79:1 > 1 data member change: > 'int blah::x' offset changed from 0 to 32 (in bits) (by +32 bits) For completeness, with a foo.symref file in the tree, genksyms would print foo.c: warning: foo: modversion changed because of changes in struct blah So there is some sort of diagnostics already. Does the abidiff tool handle the case when an exported symbol is moved between .c files? This is always a mess with genksyms, because the two .c files have different includes and thus the type expansion stops at different points. So typically the move needs to be reverted as a workaround. Michal