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=-2.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,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 816DAC433EF for ; Wed, 22 Sep 2021 02:43:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 64A89611AD for ; Wed, 22 Sep 2021 02:43:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229945AbhIVCov (ORCPT ); Tue, 21 Sep 2021 22:44:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35476 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229537AbhIVCov (ORCPT ); Tue, 21 Sep 2021 22:44:51 -0400 Received: from mail-vk1-xa35.google.com (mail-vk1-xa35.google.com [IPv6:2607:f8b0:4864:20::a35]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2A82EC061574; Tue, 21 Sep 2021 19:43:22 -0700 (PDT) Received: by mail-vk1-xa35.google.com with SMTP id b67so532395vkb.13; Tue, 21 Sep 2021 19:43:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=S7XWCRLPjasbFUjEZ4/PesuafkvYctGigM6PR8jA8qw=; b=SIZByzy3HwkCFWjz3NnCVwALKWHqHfi1PqlMrTZ68Ui6xualqU982XbxRXxNuXntu7 CEToB9R4phsCVvTljaZGidDGqsDauncHnF1dXcy2ZZiFMWpRNFBUIrOpyhblP3qfF2Zr 1iiNn6bWCEXMgKNzrkr83D8A0oIZyiaMKS/+/E9GD9PFfbO0qXIiDw6HvqBqsYNVoR3t vqqJAZ7b5KerV90DEzd4bZiJL6cEORMZYEzeTrN0mEuk0gOZnLtk1UUeRhBwc8c5yCOt oUUSxLRyOdHbqPT55+kzMqgcejPpGXiYHGLMr7Z3/2afergR13IlqKerUzOpOFploYsw Lz4g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=S7XWCRLPjasbFUjEZ4/PesuafkvYctGigM6PR8jA8qw=; b=1Rcy/XjN4Q1//Bla752u5f5Z2t/znd2b2NLR6caSBSADHgWyLYwRCj856BY9uMBhMN VevaCrydS3RB6eTaP9W/oBB67PRdlsHgjnOCxoS4TDMBgKy4/Yk4q0rb+gFAxRvZ2MYB +pekUNkGeDXPpWKfBk3PID1gSNILvg/P+xEidX7MfNH1YhtiF1SyNeNNvV1aAXQzY9Yw HnuGYCRyHglYGO/ISjjYgz8c5o2O56QwP5A6yUw1fA29pmdzzNYpGAb/q3ArnohK33aw Bm1a1W3QtUewrQRzxG7D/hzCV1OyvSpaPu1xf+2ra2bWgvfbgdMvrKaT8pJmOY/IkCGZ /M8Q== X-Gm-Message-State: AOAM532swPai85FkOQzasr6Bth5+dzgO6Ggkgofcp0bW2B7AqnQpvLhB hYn4ub0Sj8PgYLCO/t6MxodDd6TlIGciXltLffQ= X-Google-Smtp-Source: ABdhPJycEuEnNxLN1CdvRqU7yLzngAuE06/owJhp1YjUIJp4yTSHs+a0gjkaVCBc9d7A/1OBAJtQEGM88S50GfDltKE= X-Received: by 2002:a1f:1283:: with SMTP id 125mr21948982vks.2.1632278601271; Tue, 21 Sep 2021 19:43:21 -0700 (PDT) MIME-Version: 1.0 References: <20210917035736.3934017-1-chenhuacai@loongson.cn> <20210917035736.3934017-15-chenhuacai@loongson.cn> <87tuii52o2.fsf@disp2133> In-Reply-To: From: Huacai Chen Date: Wed, 22 Sep 2021 10:43:09 +0800 Message-ID: Subject: Re: [PATCH V3 14/22] LoongArch: Add signal handling support To: Richard Henderson Cc: Arnd Bergmann , "Eric W. Biederman" , Huacai Chen , Andy Lutomirski , Thomas Gleixner , Peter Zijlstra , Andrew Morton , David Airlie , Jonathan Corbet , Linus Torvalds , linux-arch , "open list:DOCUMENTATION" , LKML , Xuefeng Li , Yanteng Si , Jiaxun Yang Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org Hi, Richard, On Tue, Sep 21, 2021 at 5:14 AM Richard Henderson wrote: > > On 9/19/21 7:36 PM, Huacai Chen wrote: > > Hi, Arnd, > > > > On Sun, Sep 19, 2021 at 5:59 PM Arnd Bergmann wrote: > >> > >> On Sat, Sep 18, 2021 at 9:12 AM Huacai Chen wrote: > >>> On Sat, Sep 18, 2021 at 5:10 AM Eric W. Biederman wrote: > >>>> For example does LoongArch have a version without built in floating > >>>> point support? > >>> > >>> Some of these structures seems need rethinking, But we really have > >>> LoongArch-based MCUs now (no FP, no SMP, and even no MMU). > >> > >> NOMMU Linux is kind-of on the way out as interest is fading, so I hope you > >> don't plan on supporting this in the future. > >> > >> Do you expect to see future products with MMU but no FP or no SMP? > > OK, we will not care no-MMU hardware in Linux, but no-FP and no-SMP > > hardware will be supported. > > Please consider requiring the FP registers to be present even on no-FP hardware. > > With this plus the FP data movement instructions (FMOV, MOVGR2FR, MOVFR2GR, FLD, FST), it > is possible to implement soft-float without requiring a separate soft-float ABI. This can > vastly simplify compatibility and deployment. OK, I'll send an updated version. > > > r~