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=-6.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 DE74DC433B4 for ; Fri, 14 May 2021 13:04:50 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 0A081613B5 for ; Fri, 14 May 2021 13:04:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0A081613B5 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4FhTJc2JQfz30Cs for ; Fri, 14 May 2021 23:04:48 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=ovF/DZ6v; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=198.145.29.99; helo=mail.kernel.org; envelope-from=arnd@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=ovF/DZ6v; dkim-atps=neutral Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4FhTJ53vMlz2ymX for ; Fri, 14 May 2021 23:04:21 +1000 (AEST) Received: by mail.kernel.org (Postfix) with ESMTPSA id 018C26145E for ; Fri, 14 May 2021 13:03:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1620997427; bh=KjRucVq9b2NKDaj10nQp3ecBtpjWikZo5h6VILTp9TQ=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=ovF/DZ6vdNyVMSH9t0zjMiEagYR721FRrBVU2xZxXX/OUhYjI4DoeKwouVrElnjNo H2LSDPkvaHREyrn1HyHd22hBkz3doo6H4OkJrDEXpJxqK/vktxIuA+Y7acAYuukBaa 8O0eESoVXTaqfbi08ympBP0C9YMyag7kUEqEptmhtLOP4nWQVjNY971q4Zvmp63YMt FApG43bQoRmB4kFdndQzCDNsl0JV6NwuAMLOJTgNrK92jp4knsyOUt4/jlG789UKl4 nQaqjm0JUA5D0nUp8/StBDRTX5A//K7DIJJsrFgQEHzMgV0l+g4iKzmuREdaMda1QZ 5UKkdWqvLttRg== Received: by mail-wr1-f42.google.com with SMTP id v12so29941105wrq.6 for ; Fri, 14 May 2021 06:03:46 -0700 (PDT) X-Gm-Message-State: AOAM532BdWbJfrNUfK7gRQAFwk5KuwStoIMnp3xNEzSxXr1I0JISVBIP DU/pTZaeW95iTnKXisS5od/CAzb0lcUaADM0AAs= X-Google-Smtp-Source: ABdhPJzlvCIkpR1F+kgydYHRKzdkFDddvZpYrU9rVtIDsh8sEqa4UTJsy0hLf91X5lxvVhxcxulzbSr4KB+n1tMKazY= X-Received: by 2002:a5d:6dc4:: with SMTP id d4mr60213997wrz.105.1620997425625; Fri, 14 May 2021 06:03:45 -0700 (PDT) MIME-Version: 1.0 References: <20210514100106.3404011-1-arnd@kernel.org> <20210514100106.3404011-6-arnd@kernel.org> <20210514114813.GJ10366@gate.crashing.org> In-Reply-To: <20210514114813.GJ10366@gate.crashing.org> From: Arnd Bergmann Date: Fri, 14 May 2021 15:02:43 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2 05/13] powerpc: use linux/unaligned/le_struct.h on LE power7 To: Segher Boessenkool Content-Type: text/plain; charset="UTF-8" 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: linux-arch , Vineet Gupta , linuxppc-dev , Linux Kernel Mailing List , Paul Mackerras , Linus Torvalds Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Fri, May 14, 2021 at 1:48 PM Segher Boessenkool wrote: > On Fri, May 14, 2021 at 12:00:53PM +0200, Arnd Bergmann wrote: > > Little-endian POWER7 kernels disable > > CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS because that is not supported on > > the hardware, but the kernel still uses direct load/store for explicti > > get_unaligned()/put_unaligned(). > > > > I assume this is a mistake that leads to power7 having to trap and fix > > up all these unaligned accesses at a noticeable performance cost. > > > > The fix is completely trivial, just remove the file and use the > > generic version that gets it right. > > LE p7 isn't supported (it requires special firmware), and no one uses it > anymore, also not for development. It was used for powerpc64le-linux > development before p8 was widely available. Ok, thanks for the clarification. Should we just remove the Kconfig option for it then as further cleanup? Is there any other code such as alignment trap handling that could be removed if LE POWER7 gets dropped? Arnd