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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EE04BC433EF for ; Fri, 6 May 2022 11:47:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1388001AbiEFLut (ORCPT ); Fri, 6 May 2022 07:50:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48480 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1391497AbiEFLuq (ORCPT ); Fri, 6 May 2022 07:50:46 -0400 Received: from mout.kundenserver.de (mout.kundenserver.de [212.227.126.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B07D734B89 for ; Fri, 6 May 2022 04:47:03 -0700 (PDT) Received: from mail-yw1-f170.google.com ([209.85.128.170]) by mrelayeu.kundenserver.de (mreue010 [213.165.67.97]) with ESMTPSA (Nemesis) id 1M7aqD-1njNRn3nA5-0086j6; Fri, 06 May 2022 13:41:55 +0200 Received: by mail-yw1-f170.google.com with SMTP id 00721157ae682-2f7d19cac0bso77892637b3.13; Fri, 06 May 2022 04:41:54 -0700 (PDT) X-Gm-Message-State: AOAM531Sjh7Q45UDmZ/dNzvtvCSOV36srmPmVSs1ZzLT/GQ/8p7NsjAU gZeYQxQPAejOjygOBOJnNyoZuWeMWkbGlVwPzx4= X-Google-Smtp-Source: ABdhPJywspxQxLYUg/eOOLFrgtyTJ05Ld5wI7gPuDubfD9OWObUtSEcGtfhDxXCtuquUvGM12QufsEjCeeQ7Z/PAEvg= X-Received: by 2002:a81:2305:0:b0:2f7:dadb:2162 with SMTP id j5-20020a812305000000b002f7dadb2162mr2092280ywj.42.1651837313474; Fri, 06 May 2022 04:41:53 -0700 (PDT) MIME-Version: 1.0 References: <20220430090518.3127980-1-chenhuacai@loongson.cn> <20220430090518.3127980-21-chenhuacai@loongson.cn> In-Reply-To: From: Arnd Bergmann Date: Fri, 6 May 2022 13:41:36 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH V9 20/24] LoongArch: Add efistub booting support To: WANG Xuerui Cc: Ard Biesheuvel , Huacai Chen , Arnd Bergmann , Huacai Chen , Andy Lutomirski , Thomas Gleixner , Peter Zijlstra , Andrew Morton , David Airlie , Jonathan Corbet , Linus Torvalds , linux-arch , "open list:DOCUMENTATION" , Linux Kernel Mailing List , Xuefeng Li , Yanteng Si , Guo Ren , Jiaxun Yang Content-Type: text/plain; charset="UTF-8" X-Provags-ID: V03:K1:3kKuw8Z9zKIZX8wYjoygIzYKmuNhyVykuNFk32CspPPPKzWZaZ/ vZz7HsCc6h4T+l8r2NDeBOt0mALrlv0pJNaEPm0fbFc5DN0Ec7tlLl6RBAmffvmFvZ4jqhY ep3CKqyWVhpaOBxUfAN1ajsW0ByffWC/0uw1JFwQSZDdMwUOJ5tTjyALIe2YfdXT6xdJtSL hvQAIVNpZGylF2FsfVT7A== X-UI-Out-Filterresults: notjunk:1;V03:K0:gCA8+3q0tqc=:i/+b4dST89yjeyyyYu6ygC 29McRUsC4yZ9b7dNqMthMUJKnoRxrxy84N7ylzyIP2h8hwso/eUMZtC4z5MVqH6hQoaadpiEC XLbM1rfNDWr6NISC3wxBN857GqbaMhYPl4UL/F46moWkXgkG0XO+LqsLJ0fUQ98GlCiCiVKjL T/lnurGAWW7AVUsycnZbeR4MNFU12R0iCH4ijVhRQm7m69SeDcmknzI+zeUL69Dg49ghfgb5J YyUVqgC60RkMiJMoV9AUvYwRdA81uziVAh5UT3Z8HpeUdPUd5yZ4s88yFcu93ZvJvzqYWZxP3 UwmKCJp/Lwr3nIstwEbugdPqE3MuPTjkiavXC1npV268U383jeqaw7HOpnXfTGtViUEEqMs/K XOtz4b/e1vVHfkI0FiwY4/DQk29tOJCJHFvNrnCm7wEB48N3JgXrfpLvUC30wlGwybheqbyT3 sCvAOC0hq2AG2Luesk60Y4jM4GVsx9CRa/squklpka4sTlKPHs9KCgDPtRd62XOi/g4r/o8IP kMsiDqrN3TTYjQaAIQuf7VQ1Wuzg7OrzC2JLeT8oFDTHWj8qclDMGhe827uOxYzn6lFdUXDvB HTwR2nRw4xWLE84RsT2e62TkeJnpQiaRJDanW5s6mTOFqlujL8uiHBnGvaGw3Vdp9mTtPeuRA w8gBPxJ/X7JvA3DlP6BHskK8FbkdsgrnR5BPOGEq0s2Qi1VyOOsYjQPpGN5JeA+fvRhw= Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Fri, May 6, 2022 at 1:26 PM WANG Xuerui wrote: > On 5/6/22 16:14, Ard Biesheuvel wrote: > Or is there compatibility at all? > > It turns out that this port is already incompatible with shipped > systems, in other ways, at least since the March revision or so. I think we can treat user space compatibility separately from firmware compatibility. > So, in effect, this port is starting from scratch, and taking the chance > to fix early mistakes and oversights all over; hence my opinion is, > better do the Right Thing (tm) and give the generic codepath a chance. > > For the Loongson devs: at least, declare the struct boot_params flow > deprecated from day one, then work to eliminate it from future products, > if you really don't want to delay merging even further (it's already > unlikely to land in 5.19, given the discussion happening in LKML [3]). > It's not embarrassing to admit mistakes; we all make mistakes, and > what's important is to learn from them so we don't collectively repeat > ourselves. Agreed. I think there can be limited compatibility support for old firmware though, at least to help with the migration: As long as the interface between grub and linux has a proper definition following the normal UEFI standard, there can be both a modern grub that is booted using the same protocol and a backwards-compatible grub that can be booted from existing firmware and that is able to boot the kernel. The compatibility version of grub can be retired after the firmware itself is able to speak the normal boot protocol. Arnd