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 6ED50C0650F for ; Tue, 30 Jul 2019 17:09:52 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 BE06B206A2 for ; Tue, 30 Jul 2019 17:09:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BE06B206A2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 45yjj92H1TzDqQk for ; Wed, 31 Jul 2019 03:09:49 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=permerror (mailfrom) smtp.mailfrom=kernel.crashing.org (client-ip=63.228.1.57; helo=gate.crashing.org; envelope-from=segher@kernel.crashing.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 45yjfl39RmzDqWS for ; Wed, 31 Jul 2019 03:07:41 +1000 (AEST) 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 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 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kbuild test robot , Nick Desaulniers , Linux Kernel Mailing List , clang-built-linux , Paul Mackerras , Nathan Chancellor , linuxppc-dev Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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