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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 B9E13C433B4 for ; Sun, 2 May 2021 21:08:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8F3546112D for ; Sun, 2 May 2021 21:08:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232550AbhEBVJp (ORCPT ); Sun, 2 May 2021 17:09:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48648 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232457AbhEBVJn (ORCPT ); Sun, 2 May 2021 17:09:43 -0400 Received: from mail-lf1-x134.google.com (mail-lf1-x134.google.com [IPv6:2a00:1450:4864:20::134]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 51517C061756 for ; Sun, 2 May 2021 14:08:51 -0700 (PDT) Received: by mail-lf1-x134.google.com with SMTP id z13so5239977lft.1 for ; Sun, 02 May 2021 14:08:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ztLe0PUCKTK2LtdP2HGMOWnOHEgLtC71r4QQFdpNTzw=; b=YBiD6aB1h/sCqYhKTphH+dg0wIZGGo6mw2O+h2UbBPaKs2j+amxCQcnTb6T4EcSFDi 569RK7dsnKNOuJGN1Zq3Sl1+5gAq1k0k2Eo073vJURqtQ79ulv+UTiBKQN1QHx0TnXJL 8kMigLRMuOZq6Z9mW4YA2S0oPDLTJFBkJG6AU= 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=ztLe0PUCKTK2LtdP2HGMOWnOHEgLtC71r4QQFdpNTzw=; b=GiWu4IlK80WEw+Iv9noiDyvn1LE4FRaSYN94zkd4yt+Sb8wtOCg9rv1FnXtiN/7g9Q w4eemNpHuR3e4iXFyXp3yzMwjsQDJ69s0VgDRjmFccwoSjfXhiSfA2t8uuq74CAF2wfY JvY2ZgmfaiiRoF+qwb2Fxbhp9+l1gvf8e1RqjWm6+Pto0wylg55SvWcVE+nSCZGyGIkQ Y4RZAtNdzeCq2hRZZjF/0AyALxRdwGm2QfnwQeZFgacZbLhjKv2Z7rp8N0aa3HEF4b4u vrfJscqEfrT3rvBrhnxW3U6F7VvI9a75UF6gzacBSt40x8t/zO1UnOmzwGeiHnOy6P+p +L5A== X-Gm-Message-State: AOAM533AaHlkqksgbuHY30+C1cMC4+LphumEtb4PpQyorMWL/mth0jx+ D2PNJF3/wJyFEKSc8xi9rXh//+Dg4uP1+BWe X-Google-Smtp-Source: ABdhPJxM5qAtl+6GL+kzQmzG0vf6eclrs12/ndo4J4HVeAXMOcTUiTA+nXKzqpYb5k6Xk9rVL3fSkQ== X-Received: by 2002:a05:6512:3c91:: with SMTP id h17mr6331148lfv.106.1619989729461; Sun, 02 May 2021 14:08:49 -0700 (PDT) Received: from mail-lj1-f177.google.com (mail-lj1-f177.google.com. [209.85.208.177]) by smtp.gmail.com with ESMTPSA id h7sm944149lfu.199.2021.05.02.14.08.47 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 02 May 2021 14:08:48 -0700 (PDT) Received: by mail-lj1-f177.google.com with SMTP id s9so4515350ljj.6 for ; Sun, 02 May 2021 14:08:47 -0700 (PDT) X-Received: by 2002:a2e:330f:: with SMTP id d15mr11126850ljc.251.1619989727157; Sun, 02 May 2021 14:08:47 -0700 (PDT) MIME-Version: 1.0 References: <20210501151538.145449-1-masahiroy@kernel.org> <3943bc020f6227c8801907317fc113aa13ad4bad.camel@perches.com> <20210502183030.GF10366@gate.crashing.org> <81a926a3bdb70debe3ae2b13655ea8d249fb9991.camel@perches.com> <20210502203253.GH10366@gate.crashing.org> In-Reply-To: <20210502203253.GH10366@gate.crashing.org> From: Linus Torvalds Date: Sun, 2 May 2021 14:08:31 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] Raise the minimum GCC version to 5.2 To: Segher Boessenkool Cc: Joe Perches , Miguel Ojeda , Masahiro Yamada , Albert Ou , Arnd Bergmann , Linux Kbuild mailing list , Greg Kroah-Hartman , Jonathan Corbet , Linux Doc Mailing List , linux-kernel , Palmer Dabbelt , Paul Walmsley , Catalin Marinas , Miguel Ojeda , Paul Mackerras , linux-riscv@lists.infradead.org, linuxppc-dev , Will Deacon , Linux ARM Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, May 2, 2021 at 1:38 PM Segher Boessenkool wrote: > > The point is, you inconvenience users if you require a compiler version > they do not already have. Five years might be fine, but three years is > not. So this should be our main issue - not how old a compiler is, but how our compiler version limitations end up possibly making it harder for users to upgrade. Of course, one issue there is whether said users would have upgraded regardless - if you have a very old distribution, how likely are you to upgrade the kernel at all? But we do very much want to encourage people to upgrade their kernels, even if they might be running otherwise fairly old user space. If for no other reason than that it's good for our kernel coverage testing - the more different distributions people test a new kernel with, the better. And some of the less common architectures have their own issues, with distros possibly not even supporting them any more (if they ever did - considering all the odd ad-hoc cross-compiler builds people have had..) This is why "our clang support requires a very recent version of clang" is not relevant - distributions won't have old versions of clang anyway, and even if they do, such distributions will be gcc-based, so "build the kernel with clang" for that situation is perhaps an exercise for some intrepid person who is willing to do odd and unusual things, and might as well build their own clang version too. So I really wish people didn't get hung about some "three years ago" or similar. It's not relevant. What is relevant is what version of gcc various distributions actually have reasonably easily available, and how old and relevant the distributions are. We did decide that (just as an example) RHEL 7 was too old to worry about when we updated the gcc version requirement last time. Last year, Arnd and Kirill (maybe others were involved too) made a list of distros and older gcc versions. But I don't think anybody actually _maintains_ such a list. It would be perhaps interesting to have some way to check what compiler versions are being offered by different distros. Linus 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=-4.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 5A5A4C433B4 for ; Sun, 2 May 2021 21:16:39 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 CF0ED60FE4 for ; Sun, 2 May 2021 21:16:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CF0ED60FE4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:Cc:To:Subject:Message-ID:Date:From:In-Reply-To: References:MIME-Version:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=TazXsVXGmksVaGlyvtjyhgWoe7OIpUO1fQrgDV9omLY=; b=qk9vXI6aCKrUfnAVw5cCL+P05 tfM+eJZU6bv1pgaJamqJ4WLGP2QTgAYGTeghmy8IdAFp7RBPA99SLz0NVeVFkl/WyYD096Csv4Muc YoEmNqw7hJdXRIKCgOTot8Cao1QTaNKW3LIGA9KO9jHSldYUij3SUEpQ1ugeLdcYuNLCBh9GD8shl v4rP9Rw8nXRCRTxddd6zMu1eNXCCs7+ylAEBVePtLKZC1aQWgb1F36zWYCR0SbBvXQQd563uOzWtd jwVWMi9eqOWyaoR5khD35sbuIEhL6ap3fEZaMkGTsy5h9txyHMQbsih2aO5ESzCjlVDGPCjeZsxb1 7Zj46sImA==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1ldJRw-00CVNW-8U; Sun, 02 May 2021 21:16:24 +0000 Received: from bombadil.infradead.org ([2607:7c80:54:e::133]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1ldJRs-00CVMz-6c for linux-riscv@desiato.infradead.org; Sun, 02 May 2021 21:16:20 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Type:Cc:To:Subject:Message-ID :Date:From:In-Reply-To:References:MIME-Version:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=ztLe0PUCKTK2LtdP2HGMOWnOHEgLtC71r4QQFdpNTzw=; b=cUv8XVXvn2SeCFlM18xdScY5oO XGs3R3Bt5MPutHv2VDTDyzPcvAvjOpfkS3O90Wk3sGgcR9CIgMGael6F5C8itOibGd7WVu4J4Ke7v G+PizJTxRaQ8EhTr+tm82RR9f1Lvv9Nk/a7dhzCPrYFDTH89iR42kFjqgnuN1Hkz1XWyAQ3Fg4+tU vj1sk+ByLHbvIYHdMxpMUCvhOX0MRnP6Cb4+14Xses2Pw9rIjgPL5wxqejF1D6Ccxw76luMx+gvcF MAKssQXLCQ95bAicTHhjkQ8CV7Y8A8JaWQyaszOnxjJF4GuC4M2kr3mGfKr88Di93ukwdXs4niWxS VvM0Cg0A==; Received: from mail-lf1-x135.google.com ([2a00:1450:4864:20::135]) by bombadil.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1ldJRp-002gwg-98 for linux-riscv@lists.infradead.org; Sun, 02 May 2021 21:16:18 +0000 Received: by mail-lf1-x135.google.com with SMTP id x19so5247057lfa.2 for ; Sun, 02 May 2021 14:16:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ztLe0PUCKTK2LtdP2HGMOWnOHEgLtC71r4QQFdpNTzw=; b=YBiD6aB1h/sCqYhKTphH+dg0wIZGGo6mw2O+h2UbBPaKs2j+amxCQcnTb6T4EcSFDi 569RK7dsnKNOuJGN1Zq3Sl1+5gAq1k0k2Eo073vJURqtQ79ulv+UTiBKQN1QHx0TnXJL 8kMigLRMuOZq6Z9mW4YA2S0oPDLTJFBkJG6AU= 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=ztLe0PUCKTK2LtdP2HGMOWnOHEgLtC71r4QQFdpNTzw=; b=HL4hWcLaNqcpYcl7SA8+gur1AXni6/iCkqOapOvnQrlIUQYwInriAPNjyYk+1LY71U 2/y327b+KsBe7q6r2coDkGBnxqMQd4hdeXcqKsiV7/IyHFsRhxTfWksmQ+wwjmF8VJOB DZ2Uvzb5koTa/abBLnNr/JFZee9LrhjOxBTfhPAw8DYvWGm8gKeciX77lWVSAXN9/2HT 2ad+915VDa7oSH3r42aQ3A8Rnne5XVLHKy4TocV5paaaYhL3gtvsJT7qzFMczd1L5xdO sC4S16JKqashomYUXpCJrUNvh+oCJ/Se2vvk9Z0Y/UjrxTBh/1lJTne22ahGso1+3525 nTAQ== X-Gm-Message-State: AOAM531dR+PCpIl6bMyCwsE2VXokUTlbCsB8hSsiTUgC0WaVyd2lmDNS Lvhy1/iTeyW1c0ATnETw7zUA3RstNQCSwjh+YdQ= X-Google-Smtp-Source: ABdhPJyNfZ5QYjsL+qGd9muUl8wvrU2B31+FvINlsgLPOucFGSnCvlfZT5r6nR4MXiDPi5D5bRLhKQ== X-Received: by 2002:ac2:53a2:: with SMTP id j2mr11376197lfh.246.1619990175109; Sun, 02 May 2021 14:16:15 -0700 (PDT) Received: from mail-lf1-f41.google.com (mail-lf1-f41.google.com. [209.85.167.41]) by smtp.gmail.com with ESMTPSA id x19sm1038827ljh.50.2021.05.02.14.16.14 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 02 May 2021 14:16:14 -0700 (PDT) Received: by mail-lf1-f41.google.com with SMTP id z9so756927lfu.8 for ; Sun, 02 May 2021 14:16:14 -0700 (PDT) X-Received: by 2002:a2e:330f:: with SMTP id d15mr11126850ljc.251.1619989727157; Sun, 02 May 2021 14:08:47 -0700 (PDT) MIME-Version: 1.0 References: <20210501151538.145449-1-masahiroy@kernel.org> <3943bc020f6227c8801907317fc113aa13ad4bad.camel@perches.com> <20210502183030.GF10366@gate.crashing.org> <81a926a3bdb70debe3ae2b13655ea8d249fb9991.camel@perches.com> <20210502203253.GH10366@gate.crashing.org> In-Reply-To: <20210502203253.GH10366@gate.crashing.org> From: Linus Torvalds Date: Sun, 2 May 2021 14:08:31 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] Raise the minimum GCC version to 5.2 To: Segher Boessenkool Cc: Joe Perches , Miguel Ojeda , Masahiro Yamada , Albert Ou , Arnd Bergmann , Linux Kbuild mailing list , Greg Kroah-Hartman , Jonathan Corbet , Linux Doc Mailing List , linux-kernel , Palmer Dabbelt , Paul Walmsley , Catalin Marinas , Miguel Ojeda , Paul Mackerras , linux-riscv@lists.infradead.org, linuxppc-dev , Will Deacon , Linux ARM X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210502_141617_334075_2DC47FF9 X-CRM114-Status: GOOD ( 18.41 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Sun, May 2, 2021 at 1:38 PM Segher Boessenkool wrote: > > The point is, you inconvenience users if you require a compiler version > they do not already have. Five years might be fine, but three years is > not. So this should be our main issue - not how old a compiler is, but how our compiler version limitations end up possibly making it harder for users to upgrade. Of course, one issue there is whether said users would have upgraded regardless - if you have a very old distribution, how likely are you to upgrade the kernel at all? But we do very much want to encourage people to upgrade their kernels, even if they might be running otherwise fairly old user space. If for no other reason than that it's good for our kernel coverage testing - the more different distributions people test a new kernel with, the better. And some of the less common architectures have their own issues, with distros possibly not even supporting them any more (if they ever did - considering all the odd ad-hoc cross-compiler builds people have had..) This is why "our clang support requires a very recent version of clang" is not relevant - distributions won't have old versions of clang anyway, and even if they do, such distributions will be gcc-based, so "build the kernel with clang" for that situation is perhaps an exercise for some intrepid person who is willing to do odd and unusual things, and might as well build their own clang version too. So I really wish people didn't get hung about some "three years ago" or similar. It's not relevant. What is relevant is what version of gcc various distributions actually have reasonably easily available, and how old and relevant the distributions are. We did decide that (just as an example) RHEL 7 was too old to worry about when we updated the gcc version requirement last time. Last year, Arnd and Kirill (maybe others were involved too) made a list of distros and older gcc versions. But I don't think anybody actually _maintains_ such a list. It would be perhaps interesting to have some way to check what compiler versions are being offered by different distros. Linus _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv 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=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 8C927C433ED for ; Sun, 2 May 2021 21:15:37 +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 CCBE061221 for ; Sun, 2 May 2021 21:15:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CCBE061221 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.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 4FYJmQ67Vwz30Ff for ; Mon, 3 May 2021 07:15:34 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=google header.b=YBiD6aB1; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linuxfoundation.org (client-ip=2a00:1450:4864:20::62c; helo=mail-ej1-x62c.google.com; envelope-from=torvalds@linuxfoundation.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=google header.b=YBiD6aB1; dkim-atps=neutral Received: from mail-ej1-x62c.google.com (mail-ej1-x62c.google.com [IPv6:2a00:1450:4864:20::62c]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4FYJls3XtFz2ydH for ; Mon, 3 May 2021 07:15:02 +1000 (AEST) Received: by mail-ej1-x62c.google.com with SMTP id a4so5015149ejk.1 for ; Sun, 02 May 2021 14:15:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ztLe0PUCKTK2LtdP2HGMOWnOHEgLtC71r4QQFdpNTzw=; b=YBiD6aB1h/sCqYhKTphH+dg0wIZGGo6mw2O+h2UbBPaKs2j+amxCQcnTb6T4EcSFDi 569RK7dsnKNOuJGN1Zq3Sl1+5gAq1k0k2Eo073vJURqtQ79ulv+UTiBKQN1QHx0TnXJL 8kMigLRMuOZq6Z9mW4YA2S0oPDLTJFBkJG6AU= 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=ztLe0PUCKTK2LtdP2HGMOWnOHEgLtC71r4QQFdpNTzw=; b=Ula9cdoSCb8ggF/A6JinBGmo0IJbRqFjpg3/RLIbqdzktw1kKq9R3SI4lpz50McWY5 if4fv8J4Gm5Tn4QBLleFXQFHsJBt4nuEUlJSA5AWsrop1i/UGuX0oyEQ6HDh5vo9CpT8 4Cfv7q/Pc1M7UBXbAaC1AqnGBYZT9NnwsWS2jL8VcjNHRoHBAxPTqbCtQEJJk08HdcFp OXAT+uWUVfknv243PRrcNByViEK9RC9pdgcjjhDB96FGxorRS+tuTfU2fToZuMe2Vv6Y OCDxJssNGVLpRW8wfuHt3Pz47ENwxWmLWj3XfsKyLaixNRtaJWjnrq/phg4GEQJldGjv an/w== X-Gm-Message-State: AOAM532BoIzzFQ2ngzTzSIbvYeHvQwveU9/6mW7DZ9wOeC+jd4+dYU5w lrRImHw/3Oq4s6Yk7yrVqp0Vs+R/B0KBWaG5Clk= X-Google-Smtp-Source: ABdhPJwGC7DM+8bB8oEWRSHI2rVSEiBpDXzL7DTAhnaQ8m7e0VRiSi3oN+P4LWOxL8xXe3LY7IuH7g== X-Received: by 2002:a17:906:170a:: with SMTP id c10mr13466628eje.493.1619990097010; Sun, 02 May 2021 14:14:57 -0700 (PDT) Received: from mail-ej1-f44.google.com (mail-ej1-f44.google.com. [209.85.218.44]) by smtp.gmail.com with ESMTPSA id d25sm4611897ejd.59.2021.05.02.14.14.56 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 02 May 2021 14:14:56 -0700 (PDT) Received: by mail-ej1-f44.google.com with SMTP id t4so5045156ejo.0 for ; Sun, 02 May 2021 14:14:56 -0700 (PDT) X-Received: by 2002:a2e:330f:: with SMTP id d15mr11126850ljc.251.1619989727157; Sun, 02 May 2021 14:08:47 -0700 (PDT) MIME-Version: 1.0 References: <20210501151538.145449-1-masahiroy@kernel.org> <3943bc020f6227c8801907317fc113aa13ad4bad.camel@perches.com> <20210502183030.GF10366@gate.crashing.org> <81a926a3bdb70debe3ae2b13655ea8d249fb9991.camel@perches.com> <20210502203253.GH10366@gate.crashing.org> In-Reply-To: <20210502203253.GH10366@gate.crashing.org> From: Linus Torvalds Date: Sun, 2 May 2021 14:08:31 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] Raise the minimum GCC version to 5.2 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: Albert Ou , Catalin Marinas , Arnd Bergmann , Linux Kbuild mailing list , Greg Kroah-Hartman , Masahiro Yamada , Jonathan Corbet , Linux Doc Mailing List , linux-kernel , Miguel Ojeda , Will Deacon , Palmer Dabbelt , Paul Walmsley , Joe Perches , Paul Mackerras , linux-riscv@lists.infradead.org, Miguel Ojeda , linuxppc-dev , Linux ARM Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Sun, May 2, 2021 at 1:38 PM Segher Boessenkool wrote: > > The point is, you inconvenience users if you require a compiler version > they do not already have. Five years might be fine, but three years is > not. So this should be our main issue - not how old a compiler is, but how our compiler version limitations end up possibly making it harder for users to upgrade. Of course, one issue there is whether said users would have upgraded regardless - if you have a very old distribution, how likely are you to upgrade the kernel at all? But we do very much want to encourage people to upgrade their kernels, even if they might be running otherwise fairly old user space. If for no other reason than that it's good for our kernel coverage testing - the more different distributions people test a new kernel with, the better. And some of the less common architectures have their own issues, with distros possibly not even supporting them any more (if they ever did - considering all the odd ad-hoc cross-compiler builds people have had..) This is why "our clang support requires a very recent version of clang" is not relevant - distributions won't have old versions of clang anyway, and even if they do, such distributions will be gcc-based, so "build the kernel with clang" for that situation is perhaps an exercise for some intrepid person who is willing to do odd and unusual things, and might as well build their own clang version too. So I really wish people didn't get hung about some "three years ago" or similar. It's not relevant. What is relevant is what version of gcc various distributions actually have reasonably easily available, and how old and relevant the distributions are. We did decide that (just as an example) RHEL 7 was too old to worry about when we updated the gcc version requirement last time. Last year, Arnd and Kirill (maybe others were involved too) made a list of distros and older gcc versions. But I don't think anybody actually _maintains_ such a list. It would be perhaps interesting to have some way to check what compiler versions are being offered by different distros. Linus 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=-4.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 243BBC433B4 for ; Sun, 2 May 2021 21:10:24 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 92A0C6112F for ; Sun, 2 May 2021 21:10:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 92A0C6112F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:Cc:To:Subject:Message-ID:Date:From:In-Reply-To: References:MIME-Version:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=bxhx0dZd1QgOrB/S1AK2cfTzicJxYvDJLzQkXMfnSyg=; b=i1LuAD1YLybXqwqMYurVPqo+m JBgureaXogrmzoIE/5fBDUVoYIO/DoXPzdXE0syhipPtf61FMQbFgZ0308S+izJy4/vYQlTXAWeoa 6Ztlg/n7ElnI7ZdOM174JZZRxbLqvfuRTSAPxHjVArWzUxZF0MuDD/rROYpCqbRsQ3W06HfKWkwqT 5eP9PNW5IEnYbquFHgO9bEsZ/8DtMrI92xy3FiRhHwAZiznII3J4yTQH/3IOHLDWDjKebXvsBk67s V4ANUjvtAs6067CDzi5MoD834sijsNTsC7CyQtgi4oXx/oXJbwN9rjbs5rMaAhEopfU1wD316Ysav 5x5kvRF9g==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1ldJKj-00CUKk-3f; Sun, 02 May 2021 21:08:57 +0000 Received: from bombadil.infradead.org ([2607:7c80:54:e::133]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1ldJKf-00CUKJ-R4 for linux-arm-kernel@desiato.infradead.org; Sun, 02 May 2021 21:08:54 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Type:Cc:To:Subject:Message-ID :Date:From:In-Reply-To:References:MIME-Version:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=ztLe0PUCKTK2LtdP2HGMOWnOHEgLtC71r4QQFdpNTzw=; b=cUv8XVXvn2SeCFlM18xdScY5oO XGs3R3Bt5MPutHv2VDTDyzPcvAvjOpfkS3O90Wk3sGgcR9CIgMGael6F5C8itOibGd7WVu4J4Ke7v G+PizJTxRaQ8EhTr+tm82RR9f1Lvv9Nk/a7dhzCPrYFDTH89iR42kFjqgnuN1Hkz1XWyAQ3Fg4+tU vj1sk+ByLHbvIYHdMxpMUCvhOX0MRnP6Cb4+14Xses2Pw9rIjgPL5wxqejF1D6Ccxw76luMx+gvcF MAKssQXLCQ95bAicTHhjkQ8CV7Y8A8JaWQyaszOnxjJF4GuC4M2kr3mGfKr88Di93ukwdXs4niWxS VvM0Cg0A==; Received: from mail-lf1-x134.google.com ([2a00:1450:4864:20::134]) by bombadil.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1ldJKd-002gld-3k for linux-arm-kernel@lists.infradead.org; Sun, 02 May 2021 21:08:52 +0000 Received: by mail-lf1-x134.google.com with SMTP id j4so5264174lfp.0 for ; Sun, 02 May 2021 14:08:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ztLe0PUCKTK2LtdP2HGMOWnOHEgLtC71r4QQFdpNTzw=; b=YBiD6aB1h/sCqYhKTphH+dg0wIZGGo6mw2O+h2UbBPaKs2j+amxCQcnTb6T4EcSFDi 569RK7dsnKNOuJGN1Zq3Sl1+5gAq1k0k2Eo073vJURqtQ79ulv+UTiBKQN1QHx0TnXJL 8kMigLRMuOZq6Z9mW4YA2S0oPDLTJFBkJG6AU= 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=ztLe0PUCKTK2LtdP2HGMOWnOHEgLtC71r4QQFdpNTzw=; b=eKMD99+sGHCX4Aj6oDcSK+5qqjy0xihzNOOuxTCbLbpVn/GhuYEcaXwRj2FWel2FOH nUCUp+Ikr+SLWbisun/k21hPsLwZVrvo3ZEgJOUHqFtTKNoZM0yr6UBUK3dmfHTmZbDr pU+ow9H+Wr1JSKtFbPpthL4uE7VOsW8bzyWR+NAVTYL+1NKFdYMYBl9WkoXxxbZGr1Uk kf6Xn7IZ9Sax0bzflEGpc8ZXeXY9zGHbKl45NY01/cJnl+jVOelXuci6YHVmSpl6Evhm zrivyzhu70Gs1ihY3No13LkdnwwkTHikUpfbT3xIRS8aBsD6bIFu5fLQ/MSiLhZ6BeeT Syxw== X-Gm-Message-State: AOAM5325mMtrVH2kyGHlERoyfwqzX8S9orwrnbXANQlow3tVuJ3NpSiN WGXb5yR82xPGUxEtGP0FCH1jo+N3ayZJT6b4 X-Google-Smtp-Source: ABdhPJx3piWgm8QixbWpPo5rOMtEkvd+7IHhPWxg2QL1aY0UpOrqc3zlzE5RerHTu8rGfbhM5fSQEA== X-Received: by 2002:a19:ca04:: with SMTP id a4mr11913476lfg.588.1619989728728; Sun, 02 May 2021 14:08:48 -0700 (PDT) Received: from mail-lj1-f182.google.com (mail-lj1-f182.google.com. [209.85.208.182]) by smtp.gmail.com with ESMTPSA id z4sm1034615ljk.1.2021.05.02.14.08.47 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 02 May 2021 14:08:47 -0700 (PDT) Received: by mail-lj1-f182.google.com with SMTP id d15so4482066ljo.12 for ; Sun, 02 May 2021 14:08:47 -0700 (PDT) X-Received: by 2002:a2e:330f:: with SMTP id d15mr11126850ljc.251.1619989727157; Sun, 02 May 2021 14:08:47 -0700 (PDT) MIME-Version: 1.0 References: <20210501151538.145449-1-masahiroy@kernel.org> <3943bc020f6227c8801907317fc113aa13ad4bad.camel@perches.com> <20210502183030.GF10366@gate.crashing.org> <81a926a3bdb70debe3ae2b13655ea8d249fb9991.camel@perches.com> <20210502203253.GH10366@gate.crashing.org> In-Reply-To: <20210502203253.GH10366@gate.crashing.org> From: Linus Torvalds Date: Sun, 2 May 2021 14:08:31 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] Raise the minimum GCC version to 5.2 To: Segher Boessenkool Cc: Joe Perches , Miguel Ojeda , Masahiro Yamada , Albert Ou , Arnd Bergmann , Linux Kbuild mailing list , Greg Kroah-Hartman , Jonathan Corbet , Linux Doc Mailing List , linux-kernel , Palmer Dabbelt , Paul Walmsley , Catalin Marinas , Miguel Ojeda , Paul Mackerras , linux-riscv@lists.infradead.org, linuxppc-dev , Will Deacon , Linux ARM X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210502_140851_176896_7B48E28C X-CRM114-Status: GOOD ( 19.91 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sun, May 2, 2021 at 1:38 PM Segher Boessenkool wrote: > > The point is, you inconvenience users if you require a compiler version > they do not already have. Five years might be fine, but three years is > not. So this should be our main issue - not how old a compiler is, but how our compiler version limitations end up possibly making it harder for users to upgrade. Of course, one issue there is whether said users would have upgraded regardless - if you have a very old distribution, how likely are you to upgrade the kernel at all? But we do very much want to encourage people to upgrade their kernels, even if they might be running otherwise fairly old user space. If for no other reason than that it's good for our kernel coverage testing - the more different distributions people test a new kernel with, the better. And some of the less common architectures have their own issues, with distros possibly not even supporting them any more (if they ever did - considering all the odd ad-hoc cross-compiler builds people have had..) This is why "our clang support requires a very recent version of clang" is not relevant - distributions won't have old versions of clang anyway, and even if they do, such distributions will be gcc-based, so "build the kernel with clang" for that situation is perhaps an exercise for some intrepid person who is willing to do odd and unusual things, and might as well build their own clang version too. So I really wish people didn't get hung about some "three years ago" or similar. It's not relevant. What is relevant is what version of gcc various distributions actually have reasonably easily available, and how old and relevant the distributions are. We did decide that (just as an example) RHEL 7 was too old to worry about when we updated the gcc version requirement last time. Last year, Arnd and Kirill (maybe others were involved too) made a list of distros and older gcc versions. But I don't think anybody actually _maintains_ such a list. It would be perhaps interesting to have some way to check what compiler versions are being offered by different distros. Linus _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel