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=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 30954C0650F for ; Tue, 30 Jul 2019 18:25:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 077852087F for ; Tue, 30 Jul 2019 18:25:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729626AbfG3SZQ (ORCPT ); Tue, 30 Jul 2019 14:25:16 -0400 Received: from mail-qk1-f194.google.com ([209.85.222.194]:38410 "EHLO mail-qk1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729112AbfG3SZP (ORCPT ); Tue, 30 Jul 2019 14:25:15 -0400 Received: by mail-qk1-f194.google.com with SMTP id a27so47329286qkk.5 for ; Tue, 30 Jul 2019 11:25:15 -0700 (PDT) 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:from:date :message-id:subject:to:cc; bh=hgkfIZTZT31YAwT292CElgRNymWNb2JeX6gELGSJ0g8=; b=tz2jIMAats3GShbrBatOfygDiXbx4xC6GBe7dsfYS0myEKbOYqqFZAEE8syt92sQ2i rqjsgQr0kw+vao1ZYeV4hQbUsU7K+r7yrk8lSyp6ByzMzyQdSAqiW+x54g6D2tWjKlHs 1cyUq/PAMrUslwQ70wDk8MgUtPE2Iv0KbSAWZXw7+NHk81OggK3Kq/k+JlyiGoBbG+B6 gvKWSIxh1aRf42P9n4BhK4abEL4sLKb/na1nAtiV3WCowpcDlMXENtI7KCgUKW0YMyZw kY7SqbeIr5YOveetT/tdy0x1RvuVZ1PGWHlSPgouK9u37VSYrWawQXTxvyV36iJQ6153 AIjQ== X-Gm-Message-State: APjAAAWajXGGpJtsqSMRHuMmOPxPNmJCoeV3sfl/BK1GZmA/GM6R4y3H 4T9GCjB5Yki6cS1LMa4Wapdj9hraObLzyzFNeWCeiiFb X-Google-Smtp-Source: APXvYqzFirM6D707r7849pKu3mn8W9JDE1PQUJxlpX8j1dY4OgVkWtzE1LzAAxSPeGNSezpGWMOaXX5pMloR0DGpBHM= X-Received: by 2002:a05:620a:b:: with SMTP id j11mr43867129qki.352.1564511114607; Tue, 30 Jul 2019 11:25:14 -0700 (PDT) MIME-Version: 1.0 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> <20190730170728.GQ31406@gate.crashing.org> In-Reply-To: <20190730170728.GQ31406@gate.crashing.org> From: Arnd Bergmann Date: Tue, 30 Jul 2019 20:24:58 +0200 Message-ID: Subject: Re: [PATCH] powerpc: workaround clang codegen bug in dcbz To: Segher Boessenkool Cc: kbuild test robot , Nick Desaulniers , Linux Kernel Mailing List , clang-built-linux , Paul Mackerras , Nathan Chancellor , linuxppc-dev 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 Tue, Jul 30, 2019 at 7:07 PM Segher Boessenkool wrote: > > 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? gcc-4.6, but an architecture can require a higher version. Arnd