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_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 99D30C04AAF for ; Mon, 20 May 2019 09:26:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 765F720675 for ; Mon, 20 May 2019 09:26:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732055AbfETJ0C (ORCPT ); Mon, 20 May 2019 05:26:02 -0400 Received: from mail-qt1-f194.google.com ([209.85.160.194]:33406 "EHLO mail-qt1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729357AbfETJ0C (ORCPT ); Mon, 20 May 2019 05:26:02 -0400 Received: by mail-qt1-f194.google.com with SMTP id m32so15500633qtf.0 for ; Mon, 20 May 2019 02:26:01 -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=JctNbqwCh+WC0TVQRye/r7+oJO/aUarkrBr7ivkC6/o=; b=VsHtOE34lK+CD3AvPJbCXC2icSOevCjgzq5TLXYAsakpociB+DrMJ5T3yViXyOCm8/ 3u271aT3PrT8PK9SNgH52EbxWB9BXNmxmaZMiuNARAUSwbK97n5e5eIsBh6HGJKTf0e0 aaXA4nFEd+yTVCJ599Pu9FbOPpZehw+CufVc05VKDGJcS58n8H5Z73WziXN0Y1Wb0FHG BHcycNfqlCvrUR9b6IXK70lqSP49i5DQlFqrADSwJIp6qu57JpJAJkYpEZ+pwrltSrLA MdKlOGbiDoWXM62F9Pt24WGYu1LJv+ZIMi0eWIC+7iZukTkZYT8l2IU+kfxUpAKq4Nz/ NSTw== X-Gm-Message-State: APjAAAX6Ogc9ABIvpZstO54nSOlTf6N96vaROaXBPO23C9767ObNE6mC Z72qOUtwYrFSy9jxI/tGF69Mfy0xSdxT3RsX+yw= X-Google-Smtp-Source: APXvYqwWFFg8iqO2pEVzmzHeh6gtzK9wwts/yfXyepEIpCbzxiWfMYaKQvMwkrVVdXXkTDdMOIVNSTGBZM3SRS/EUh0= X-Received: by 2002:ac8:6750:: with SMTP id n16mr39381624qtp.142.1558344361121; Mon, 20 May 2019 02:26:01 -0700 (PDT) MIME-Version: 1.0 References: <20190512012508.10608-1-elder@linaro.org> <20190512012508.10608-10-elder@linaro.org> <14a040b6-8187-3fbc-754d-2e267d587858@linaro.org> <4a34d381-d31d-ea49-d6d3-3c4f632958e3@linaro.org> In-Reply-To: From: Arnd Bergmann Date: Mon, 20 May 2019 11:25:44 +0200 Message-ID: Subject: Re: [PATCH 09/18] soc: qcom: ipa: GSI transactions To: Alex Elder Cc: David Miller , Bjorn Andersson , Ilias Apalodimas , syadagir@codeaurora.org, mjavid@codeaurora.org, evgreen@chromium.org, Ben Chan , Eric Caruso , abhishek.esse@gmail.com, Linux Kernel Mailing List 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 Sun, May 19, 2019 at 7:11 PM Alex Elder wrote: > On 5/17/19 1:44 PM, Alex Elder wrote: > > On 5/17/19 1:33 PM, Arnd Bergmann wrote: > >> On Fri, May 17, 2019 at 8:08 PM Alex Elder > > So it seems that I must *not* apply a volatile qualifier, > because doing so restricts the compiler from making the > single instruction optimization. Right, I guess that makes sense. > If I've missed something and you have another suggestion for > me to try let me know and I'll try it. A memcpy() might do the right thing as well. Another idea would be a cast to __int128 like #ifdef CONFIG_ARCH_SUPPORTS_INT128 typedef __int128 tre128_t; #else typedef struct { __u64 a; __u64 b; } tre128_t; #else static inline void set_tre(struct gsi_tre *dest_tre, struct gs_tre *src_tre) { *(volatile tre128_t *)dest_tre = *(tre128_t *)src_tre; } Arnd