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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1B91FC433DF for ; Mon, 6 Jul 2020 18:30:59 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DE66C20663 for ; Mon, 6 Jul 2020 18:30:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="pXvCYWhB"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="qbfi+0eU" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DE66C20663 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=gaoi32Xhog/JwfThYHOn9jD2tEbyr5yGS10y5Q+lgto=; b=pXvCYWhB5qO8IbCr1kcm6SLvk CLZAtoEGnWVA5hDGUYXvbCAHkvk/2T2HrNwAQtReqe9s5OE5tAmobO+VrVMQai9POeHvJpU4HXP2b eYtC+qsqhlBYFtsAsNWmse+ObYk3hQjoGlXW20t7/rzfeLMX7oyNC1CaoBKhCfcNxleq/bGT2EbQN DYKb2PdAslUimKSbvKrUG+YbGuqKsxbjtxaRlS20SwvlRKeRF/IRwcarT8YUo4AvX0lxofAdyREJX 8B9quzCWYA91danTvx8yyAJOAASRtPKlquAkJEMOzTFIValcBGeZo8OPzyVA5GDZdcu1HcoiN+u3x rguYJI4mA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jsVs4-00044k-45; Mon, 06 Jul 2020 18:29:40 +0000 Received: from casper.infradead.org ([2001:8b0:10b:1236::1]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jsVs1-00044P-Rg for linux-arm-kernel@merlin.infradead.org; Mon, 06 Jul 2020 18:29:37 +0000 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=Do5ubF9fSscGPClrokRq/R+dJR1UND+xOUqU52LNcLY=; b=qbfi+0eUNgOUvrS/172K4oJy+c +6cvYoTiN6i7rxY2lKCxArxd7eY83amayJ59D8O1py/4d9s6P4RqhHn1YxV7zVXeTetbIlRbo28Ie gCd9otH5ECaPEhZ8Ge/IBJo3+RpoisW5Ms4DZ89U+kQmjoKqC/4gOLn1rpAjmh910g68gBREeN853 D9OutRrJ3YidRcvHov/mXEAHK/teWgqK5dRcbklwPj7Zu+LAUPsEALJWfBtbZMLbt9OhdAf3SVyqB t12O6B1a3TCkvPr8cZa7kIvTauI0iVcGCIWrMpjaav/KQZRjPDPGe/rm2UlYyWtRnwA22XnbRhDgo CON822NQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jsVrx-0007O5-Sd; Mon, 06 Jul 2020 18:29:34 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 13EBC3013E5; Mon, 6 Jul 2020 20:29:26 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 06776213912F6; Mon, 6 Jul 2020 20:29:26 +0200 (CEST) Date: Mon, 6 Jul 2020 20:29:26 +0200 From: Peter Zijlstra To: "Paul E. McKenney" Subject: Re: [PATCH 00/22] add support for Clang LTO Message-ID: <20200706182926.GH4800@hirez.programming.kicks-ass.net> References: <20200701114027.GO4800@hirez.programming.kicks-ass.net> <20200701140654.GL9247@paulmck-ThinkPad-P72> <20200701150512.GH4817@hirez.programming.kicks-ass.net> <20200701160338.GN9247@paulmck-ThinkPad-P72> <20200702082040.GB4781@hirez.programming.kicks-ass.net> <20200702175948.GV9247@paulmck-ThinkPad-P72> <20200703131330.GX4800@hirez.programming.kicks-ass.net> <20200703144228.GF9247@paulmck-ThinkPad-P72> <20200706162633.GA13288@paulmck-ThinkPad-P72> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200706162633.GA13288@paulmck-ThinkPad-P72> X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch , Marco Elver , "maintainer:X86 ARCHITECTURE \(32-BIT AND 64-BIT\)" , Kees Cook , Kernel Hardening , Greg Kroah-Hartman , Masahiro Yamada , Linux Kbuild mailing list , Nick Desaulniers , LKML , clang-built-linux , Sami Tolvanen , linux-pci@vger.kernel.org, Will Deacon , Linux ARM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Jul 06, 2020 at 09:26:33AM -0700, Paul E. McKenney wrote: > And perhaps more constructively, we do need to prioritize address and data > dependencies over control dependencies. For one thing, there are a lot > more address/data dependencies in existing code than there are control > dependencies, and (sadly, perhaps more importantly) there are a lot more > people who are convinced that address/data dependencies are important. If they do not consider their Linux OS running correctly :-) > For another (admittedly more theoretical) thing, the OOTA scenarios > stemming from control dependencies are a lot less annoying than those > from address/data dependencies. > > And address/data dependencies are as far as I know vulnerable to things > like conditional-move instructions that can cause problems for control > dependencies. > > Nevertheless, yes, control dependencies also need attention. Today I added one more \o/ _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel