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=-8.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS autolearn=ham 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 8B5FDC433E1 for ; Sat, 22 Aug 2020 09:23:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 67384207C3 for ; Sat, 22 Aug 2020 09:23:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="AUQziiOp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727063AbgHVJXh (ORCPT ); Sat, 22 Aug 2020 05:23:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49830 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725864AbgHVJXe (ORCPT ); Sat, 22 Aug 2020 05:23:34 -0400 Received: from mail-oi1-x243.google.com (mail-oi1-x243.google.com [IPv6:2607:f8b0:4864:20::243]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 83CC5C061573 for ; Sat, 22 Aug 2020 02:23:34 -0700 (PDT) Received: by mail-oi1-x243.google.com with SMTP id l84so3664089oig.10 for ; Sat, 22 Aug 2020 02:23:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:reply-to:from:date:message-id :subject:to:cc; bh=HXml0ksMnzvv0PRQAiLA54DGPaMuEoNWDNqurufgFqc=; b=AUQziiOpLs7N4SZ+gDZAYjJxm3LXmSdWYH7qbJJUJ6dRrBh2p7H6ceokvgdCT6iR1Y RzRW7aOOgRZl2uwtIQz1CXHY3i5Sn4eTL2rciBvcpYhEgZoElwzhfpicxRjnZKvwxWBN Rr7yGJi8Ndgcjh/RRcf6sDS+chSmNNd86C22BjZXiWPQfRcYLC0j1NWtavYcS2AoyCPn ICG5vWq8fLfDKLtDrdq/MLfYMFa5nD2tyiWlvfoi+F/HqxUBBWO4LxjFprlw8VeRkT+3 fIshfOzQzGy4UVv5S4ShHx9c0Ps20+WVGywxZgoBwBPss3+4zpq8c6lRhP9W0nEEOud8 CXSA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:reply-to :from:date:message-id:subject:to:cc; bh=HXml0ksMnzvv0PRQAiLA54DGPaMuEoNWDNqurufgFqc=; b=E2Abf//Rkje+HU8d3bOI3BktKHyrccOC9tY3q1dSSuDLltvMf+fRVh/WoBqB8kDRwb juJeBp3nXbZW840T4iVlG+TXRwLgZwYJmxUs9vxkNFf6PEnyBzNVRyeX6ol2BNjED56o 0J6JyBlPMHZ3MM9UjLk/Cq9P+Fq5DzDVOJKYchiWklMoWQXOfkZECYixQ/x3eNDbeJ9k iuKGTorCZmiVJw2fnUdjrv8g5lLyGFd2vNHyHfQvH3HirGiLcXk++OtnybuSfhOmnjMG jo/tEmQKaGReFuzGIZFmpSTaGk7fo3dNq19lCcIhpNIDFnYbGuYfXC2wDvK9A7DyoHMd DfeA== X-Gm-Message-State: AOAM5335r3HKbZ1M1shf7V/XYgVxdkbczUJStMGqyzmidQWWPHIGEyej kBz+iMEZHpyDzzAyIv5itycJ9Jz2MgCFLVfZ/54= X-Google-Smtp-Source: ABdhPJyYzMqqJ5iIG3OiSuDBhMH+/5T4EJSfWsASkkoSZDm+wjfZ+0Xn4EX4uMvhQ1laDl0gYUVxOJBry4Dsb9d/XSs= X-Received: by 2002:aca:acd5:: with SMTP id v204mr523966oie.35.1598088213901; Sat, 22 Aug 2020 02:23:33 -0700 (PDT) MIME-Version: 1.0 References: <87h7t6tpye.fsf@nanos.tec.linutronix.de> <20200813173701.GC4295@paulmck-ThinkPad-P72> <20200813180933.GA532283@rani.riverdale.lan> <875z9dioll.fsf@nanos.tec.linutronix.de> <20200820130641.GA536306@rani.riverdale.lan> <87zh6ohm03.fsf@nanos.tec.linutronix.de> <20200821230435.GA56974@rani.riverdale.lan> <87eenzqzmr.fsf@nanos.tec.linutronix.de> <20200822035552.GA104886@rani.riverdale.lan> <20200822084133.GL28786@gate.crashing.org> In-Reply-To: <20200822084133.GL28786@gate.crashing.org> Reply-To: sedat.dilek@gmail.com From: Sedat Dilek Date: Sat, 22 Aug 2020 11:23:21 +0200 Message-ID: Subject: Re: [PATCH] x86: work around clang IAS bug referencing __force_order To: Segher Boessenkool Cc: Arvind Sankar , Thomas Gleixner , Nick Desaulniers , "Paul E. McKenney" , Ingo Molnar , Arnd Bergmann , Borislav Petkov , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , "H. Peter Anvin" , "Kirill A. Shutemov" , Zhenzhong Duan , Kees Cook , Peter Zijlstra , Juergen Gross , Andy Lutomirski , Andrew Cooper , LKML , clang-built-linux , Will Deacon , Linus Torvalds Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Aug 22, 2020 at 10:42 AM Segher Boessenkool wrote: > > Hi Arvind, > > On Fri, Aug 21, 2020 at 11:55:52PM -0400, Arvind Sankar wrote: > > Cc Segher. > > > > Segher, we were looking at gcc PR82602, where IRA could reorder volatile > > asm's (reported on ARM). The fix was backported to gcc-6. > > I know ;-) > > > Do you know if > > there is any reason the problem couldn't occur on x86 on older gcc > > without the fix? > > No, I see no particular reason, at least GCC 5 seems vulnerable. (The > GCC 5 release branch was closed at the time this bug report was made, > already). There is no reason I see why it would work on x86 but fail > elsewhere, either. > [1] says: Current Minimal Requirements ... ====================== =============== ======================================== Program Minimal version Command to check the version ====================== =============== ======================================== GNU C 4.9 gcc --version - Sedat - [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/changes.rst#n32