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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 63E8FC41514 for ; Tue, 30 Jul 2019 17:07:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 45B75206A2 for ; Tue, 30 Jul 2019 17:07:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729111AbfG3RHw (ORCPT ); Tue, 30 Jul 2019 13:07:52 -0400 Received: from gate.crashing.org ([63.228.1.57]:41566 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728647AbfG3RHv (ORCPT ); Tue, 30 Jul 2019 13:07:51 -0400 Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id x6UH7TlS016550; Tue, 30 Jul 2019 12:07:29 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id x6UH7SxN016549; Tue, 30 Jul 2019 12:07:28 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Tue, 30 Jul 2019 12:07:28 -0500 From: Segher Boessenkool To: Arnd Bergmann Cc: kbuild test robot , Nick Desaulniers , Linux Kernel Mailing List , clang-built-linux , Paul Mackerras , Nathan Chancellor , linuxppc-dev Subject: Re: [PATCH] powerpc: workaround clang codegen bug in dcbz Message-ID: <20190730170728.GQ31406@gate.crashing.org> References: <20190729202542.205309-1-ndesaulniers@google.com> <20190729203246.GA117371@archlinux-threadripper> <20190729215200.GN31406@gate.crashing.org> <20190730134856.GO31406@gate.crashing.org> <20190730161637.GP31406@gate.crashing.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190730161637.GP31406@gate.crashing.org> User-Agent: Mutt/1.4.2.3i Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 30, 2019 at 11:16:37AM -0500, Segher Boessenkool wrote: > in_le32 and friends? Yeah, huh. If LLVM copies that to the stack as > well, its (not byte reversing) read will be atomic just fine, so things > will still work correctly. > > The things defined with DEF_MMIO_IN_D (instead of DEF_MMIO_IN_X) do not > look like they will work correctly if an update form address is chosen, > but that won't happen because the constraint is "m" instead of "m<>", > making the %Un pretty useless (it will always be the empty string). Btw, this is true since GCC 4.8; before 4.8, plain "m" *could* have an automodify (autoinc, autodec, etc.) side effect. What is the minimum GCC version required, these days? https://gcc.gnu.org/PR44492 https://gcc.gnu.org/r161328 Segher