From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 13BCCC77B72 for ; Mon, 17 Apr 2023 07:48:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229771AbjDQHsd (ORCPT ); Mon, 17 Apr 2023 03:48:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37764 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229627AbjDQHsd (ORCPT ); Mon, 17 Apr 2023 03:48:33 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 133C4199F for ; Mon, 17 Apr 2023 00:48:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=16wShpQ2SZ9Pjr/snGdPBKPeyE71nS1YfqyKAcr8MCQ=; b=Qgv9m4PiJiklOuj22tOgf6Luoy 7wZB9bA7kHfqb0YGHoVkrgCZWw7PbuRqgP6EpLi9ymEPqdKGeoHcoXZPHpHupk6mYxVuwDxyC3Hm3 hQaaElJk3TZH4RyRpt/eKrY2cKW/GOuV5hZUz70tDmQB1S64RakqirojU9fi9iu7pETZcp+xXxV0o ojrYU5RdwcoTJSkthJQ+W6aw5EmOq0pYBULDnvzpUThbeSsz7EzuRRnUwejoXtJJfwJdeKOZiPGnZ g1oVBoSpq8tIzvlnZyeR/GrPOUImV0F1u1HYZHYIFPCHjL/HF4n0TxuNrgYRT5lBaD6xbqhD9gznD EAM/6vLg==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1poJav-00B6a3-66; Mon, 17 Apr 2023 07:48:13 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id A6810300237; Mon, 17 Apr 2023 09:48:11 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 4992B23EAE806; Mon, 17 Apr 2023 09:48:11 +0200 (CEST) Date: Mon, 17 Apr 2023 09:48:11 +0200 From: Peter Zijlstra To: Josh Poimboeuf Cc: Mark Rutland , Miroslav Benes , jikos@kernel.org, pmladek@suse.com, joe.lawrence@redhat.com, nstange@suse.de, mpdesouza@suse.de, broonie@kernel.org, live-patching@vger.kernel.org, Nick Desaulniers , "Jose E. Marchesi" , Miguel Ojeda Subject: Re: Live Patching Microconference at Linux Plumbers Message-ID: <20230417074811.GE83892@hirez.programming.kicks-ass.net> References: <20230414171255.oylmsdizl4waao4t@treble> <20230414193013.GB778423@hirez.programming.kicks-ass.net> <20230415043949.7y4tvshe26zday3e@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230415043949.7y4tvshe26zday3e@treble> Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org On Fri, Apr 14, 2023 at 09:39:49PM -0700, Josh Poimboeuf wrote: > Instead, the idea is for objtool to continue to reverse-engineer the CFG > as it does today (albeit with a little help from the compiler in > specific problematic areas, e.g. noreturns and jump tables). Yes, that would be best. I was merely suggesting that as a stop gap measure -- until compilers can get us this -- we might perhaps optionally extract this from DWARF. But yeah, I'm not a great fan of using DWARF as input for this either.