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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 CCA2FC4360F for ; Tue, 2 Apr 2019 08:54:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 99F6720857 for ; Tue, 2 Apr 2019 08:54:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729627AbfDBIys (ORCPT ); Tue, 2 Apr 2019 04:54:48 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:34121 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729030AbfDBIys (ORCPT ); Tue, 2 Apr 2019 04:54:48 -0400 Received: from [5.158.153.52] (helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1hBFBp-00006F-AE; Tue, 02 Apr 2019 10:54:41 +0200 Date: Tue, 2 Apr 2019 10:54:40 +0200 (CEST) From: Thomas Gleixner To: Andi Kleen cc: Andi Kleen , x86@kernel.org, Andrew Morton , LKML , Josh Poimboeuf Subject: Re: [PATCH 02/17] x86, lto: Mark all top level asm statements as .text In-Reply-To: Message-ID: References: <20190326213803.GN18020@tassilo.jf.intel.com> <20190327005523.bbxxittqf4d5bdz5@two.firstfloor.org> <20190327145918.GU18020@tassilo.jf.intel.com> <20190327154522.GV18020@tassilo.jf.intel.com> <20190327204049.GW18020@tassilo.jf.intel.com> <20190327222914.GX18020@tassilo.jf.intel.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 27 Mar 2019, Thomas Gleixner wrote: > On Wed, 27 Mar 2019, Andi Kleen wrote: > > > > > I checked the code general and with the .globl in NATIVE_LABEL the > > > > > > With or without? I removed that as well. > > > > With. > > > > LTO would still need the .globls because the variable and the asm > > statement can end up in different assembler files, and resolution > > would rely on the linker. > > This really sucks. As this is a constant source of trouble, we might better > bite the bullet and get rid of this fancy macro completely. It's not that > we add these patch patterns every other day. > > So a good old: > > /* xor %eax %ex */ > static const unsigend char patch_qspinlock[] = { 0x31, 0xc0 }; > > and then in the patch code: > > return paravirt_patch_insns(ibuf, len, patch_qspinlock, > patch_qspinlock + ARRAY_SIZE(patch_qspinlock)); > > might be less trouble than dealing with that clever inline assembly > forever. Just for the record. GCC people have confirmed that all the constructs suck in one way or the other and are just working by chance. So the above is the sanest solution. Thanks, tglx