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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,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 AC92EC433DF for ; Tue, 11 Aug 2020 13:48:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7F1622076B for ; Tue, 11 Aug 2020 13:48:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728740AbgHKNsV (ORCPT ); Tue, 11 Aug 2020 09:48:21 -0400 Received: from pegase1.c-s.fr ([93.17.236.30]:1630 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728532AbgHKNsQ (ORCPT ); Tue, 11 Aug 2020 09:48:16 -0400 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 4BQvKy5jqDz9vCqH; Tue, 11 Aug 2020 15:48:06 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id T6AfGy8k89Hu; Tue, 11 Aug 2020 15:48:06 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 4BQvKy4SfWz9vCqD; Tue, 11 Aug 2020 15:48:06 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 3FD6A8BB86; Tue, 11 Aug 2020 15:48:08 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id K8SJqBJ0A9aJ; Tue, 11 Aug 2020 15:48:08 +0200 (CEST) Received: from [172.25.230.100] (po15451.idsi0.si.c-s.fr [172.25.230.100]) by messagerie.si.c-s.fr (Postfix) with ESMTP id DD8758BB80; Tue, 11 Aug 2020 15:48:07 +0200 (CEST) Subject: Re: [RFC PATCH v1] power: don't manage floating point regs when no FPU To: Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org References: <95c00a811897f6d9176d30bf2ac92dab8c9c8e95.1596816789.git.christophe.leroy@csgroup.eu> <87o8nh9yjd.fsf@mpe.ellerman.id.au> From: Christophe Leroy Message-ID: <9edf75a2-103d-ea01-2f53-dbb467047d13@csgroup.eu> Date: Tue, 11 Aug 2020 15:48:07 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <87o8nh9yjd.fsf@mpe.ellerman.id.au> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 11/08/2020 à 14:07, Michael Ellerman a écrit : > Christophe Leroy writes: >> There is no point in copying floating point regs when there >> is no FPU and MATH_EMULATION is not selected. > > Yeah I guess you're right. I've never touched a system with neither, but > if such a thing exists then it does seem silly to copy regs around that > can't be used. Yes that exists, because glibc implements floating point emulation and it is definitely more efficient to rely of glibc emulation than kernel one. >> 10 files changed, 44 insertions(+), 1 deletion(-) > > In general this looks fine. > > It's a bit #ifdef heavy. Maybe some of those can be cleaned up a bit > with some wrapper inlines? > Yes I'll try and respin, as part of a series I'm preparing to switch the 32 bits signal code to using user_access_begin() logic and unsafe_put_user() and friends to reduce KUAP unlock/lock. Christophe