Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754459AbbFJTn0 (ORCPT ); Wed, 10 Jun 2015 15:43:26 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43245 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754088AbbFJTnT (ORCPT ); Wed, 10 Jun 2015 15:43:19 -0400 Date: Wed, 10 Jun 2015 14:43:17 -0500 From: Josh Poimboeuf To: Andi Kleen Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Michal Marek , Peter Zijlstra , Andy Lutomirski , Borislav Petkov , Linus Torvalds , x86@kernel.org, live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 00/10] x86/asm: Compile-time asm code validation Message-ID: <20150610194317.GC1125@treble.redhat.com> References: <20150610130814.GN19417@two.firstfloor.org> <20150610135203.GA19509@treble.redhat.com> <20150610141104.GQ19417@two.firstfloor.org> <20150610143209.GA28843@treble.redhat.com> <20150610150412.GR19417@two.firstfloor.org> <20150610153155.GB29724@treble.redhat.com> <20150610165056.GC29724@treble.redhat.com> <87h9qf5rtk.fsf@tassilo.jf.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <87h9qf5rtk.fsf@tassilo.jf.intel.com> User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1473 Lines: 35 On Wed, Jun 10, 2015 at 11:41:43AM -0700, Andi Kleen wrote: > Josh Poimboeuf writes: > > > > If you're wanting something like -freorder-blocks-and-partition for asm > > code, maybe we could implement something analagous to the > > likely()/unlikely() macros, to allow the hot and cold portions to be > > placed into different sections. (I could then teach asmvalidate how to > > validate such code.) > > > > Would that be useful? > > Eventually you have to handle dwarf4, because that's the only way to > handle the gcc generated code. > > So your tool just needs to understand the dwarf. It's ok to warn > about assembler code that is not correctly annotated, and fix it > then. Ok, I think we're talking about two different things. Maybe you're mixing up this patch set with some of the other things we've discussed like the DWARF CFI generation tool or the runtime DWARF unwinder. This patch set is only concerned with enforcing sane rules on asm code. It has nothing to do with understanding DWARF. In fact, since Ingo reverted the CFI annotations, there is currently no DWARF in asm code at all. This patch set is a prerequisite for the other DWARF stuff we talked about previously. -- Josh -- 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/