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=-10.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MENTIONS_GIT_HOSTING,SPF_HELO_NONE, SPF_PASS autolearn=ham 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 A4524C4338F for ; Tue, 3 Aug 2021 12:29:18 +0000 (UTC) Received: by mail.kernel.org (Postfix) id 7D47860FA0; Tue, 3 Aug 2021 12:29:18 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 625BD60F56; Tue, 3 Aug 2021 12:29:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1627993758; bh=CdMdo7VqEhOqOW8v9CPwGDUDVowXGaioSYBwccf45xg=; h=References:In-Reply-To:From:Date:Subject:To:List-Id:Cc:From; b=ULuqlMlpBwWgLW82sbAqhYSTr8asnxuhGKxrTy7bMZqSXIypT5wO9lLqDISIWVwCQ OAclj0t6cJvCu+6gmiUitxlIqetGBt9YbRJ52Pk86rHFUI34b03Uqj89cTPShxDgSH 9439LijulHZymPKepafmhgW1XJ9hlY5sDg0ygxa6r+xOj2pUPqpPuc+/m7Eot2HQc9 wgRlAod+2jt1avp5IHpypf4gHlVg9dye7Aiauv6MKqBEqvWUJCoSeEIepO02WtMty3 ZrfJUa9iDnHlwheUz+Fk7xce0MODnNWbfon7mwBe3bJZ0kgy98+KGXjY5pxbBfc3KM XuMEaNH9pAPQg== Received: by mail-wm1-f52.google.com with SMTP id l4-20020a05600c1d04b02902506f89ad2dso1785416wms.1; Tue, 03 Aug 2021 05:29:18 -0700 (PDT) X-Gm-Message-State: AOAM530v0Y6zqptFSFyHTAwyow6n+rLdNk7EFRGLHA7RfVo09quR5cnZ Ly/pEfJyriq4+CMPvvUPb71AO1EfWiSnKgwG1CI= X-Google-Smtp-Source: ABdhPJyli+UFFruAa933Tm1+U1g/8oxWoQ+AO85gp2Zg5a2H1T9MUphx/Qm9fgrTO9M6+cdv/uHOEehAGahl3VCXD+I= X-Received: by 2002:a1c:208e:: with SMTP id g136mr4091091wmg.142.1627993756987; Tue, 03 Aug 2021 05:29:16 -0700 (PDT) MIME-Version: 1.0 References: <20210802141245.1146772-1-arnd@kernel.org> In-Reply-To: From: Arnd Bergmann Date: Tue, 3 Aug 2021 14:29:00 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] ARM: ep93xx: remove MaverickCrunch support To: Linus Walleij List-Id: Cc: Martin Guy , Russell King , Hartley Sweeten , Alexander Sverdlin , SoC Team , Nikita Shubin , Arnd Bergmann , Oleg Nesterov , Hubert Feurstein , Lukasz Majewski , Catalin Marinas , Will Deacon , Nathan Chancellor , Nick Desaulniers , Linux ARM , linux-kernel , clang-built-linux Content-Type: text/plain; charset="UTF-8" On Tue, Aug 3, 2021 at 2:12 PM Linus Walleij wrote: > > On Mon, Aug 2, 2021 at 5:45 PM Martin Guy wrote: > > > > was removed from gcc in its 4.8 release in 2012. > > > > I was sad about that, as I had managed to get it working correctly in > > 4.2 4.3 and 4.4. > > Unfortunately the GCC ARM maintainer at the time was paid by ARM, and > > they had no interest in it, as I gather the ARM-Cirrus partnership > > ended up disappointingly. > > Political issues aside, have you considered contributing support > to LLVM instead? > > It currently doesn't even support ARMv4 AFAIK but reportedly > has an easier to use and maintain back-end. (I do not know if > this is true, I just browsed this: > https://llvm.org/docs/WritingAnLLVMBackend.html ) > Current ARM Targets are here: > https://github.com/llvm/llvm-project/tree/main/llvm/lib/Target/ARM > And they have a very clear and straight-forward developer policy: > https://llvm.org/docs/DeveloperPolicy.html > > If ARMv4 support could be added to LLVM, that would solve > a lot of my headaches for ARM32, where we have things like > SA110 being actively maintained. I think for ARMv4 support, the only thing we need from llvm is to have R_ARM_V4BX relocations, and for lld to support the --fix-v4bx switch that turns 'bx' instructions into 'mov' when those relocations are found. This is something that we have previously discussed with the llvm developers and that may easily happen. For the Crunch support, I don't think it's worth spending any effort on adding that to llvm. If there are any remaining users, they have probably stopped upgrading their user space long ago (to be confirmed). The SoC itself has been "not recommended for new design" since 2019, so we are unlikely to see new users of the platform in the future, and I think existing users are equally unlikely to move from softfp to crunch even if they have the option. Arnd 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=-9.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE, SPF_PASS autolearn=ham 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 E89AFC4320A for ; Tue, 3 Aug 2021 12:54:35 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 BDBE760FC2 for ; Tue, 3 Aug 2021 12:54:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org BDBE760FC2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; 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Tue, 03 Aug 2021 05:29:18 -0700 (PDT) X-Gm-Message-State: AOAM532XCgV8WwWEKCq/zWXlkrDbkOD9+9KYb9cMwCWmj73PIfU/R6To sEyXfpONT30KYuXge7CGP6tNReyhXaF4nVH1oqg= X-Google-Smtp-Source: ABdhPJyli+UFFruAa933Tm1+U1g/8oxWoQ+AO85gp2Zg5a2H1T9MUphx/Qm9fgrTO9M6+cdv/uHOEehAGahl3VCXD+I= X-Received: by 2002:a1c:208e:: with SMTP id g136mr4091091wmg.142.1627993756987; Tue, 03 Aug 2021 05:29:16 -0700 (PDT) MIME-Version: 1.0 References: <20210802141245.1146772-1-arnd@kernel.org> In-Reply-To: From: Arnd Bergmann Date: Tue, 3 Aug 2021 14:29:00 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] ARM: ep93xx: remove MaverickCrunch support To: Linus Walleij List-Id: Cc: Martin Guy , Russell King , Hartley Sweeten , Alexander Sverdlin , SoC Team , Nikita Shubin , Arnd Bergmann , Oleg Nesterov , Hubert Feurstein , Lukasz Majewski , Catalin Marinas , Will Deacon , Nathan Chancellor , Nick Desaulniers , Linux ARM , linux-kernel , clang-built-linux X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210803_052919_121089_B35AAFBC X-CRM114-Status: GOOD ( 23.80 ) 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 Message-ID: <20210803122900.pChOzg1r19U-_40sRp9RuRPXTzFks3zp4VUXJ7rKVBw@z> On Tue, Aug 3, 2021 at 2:12 PM Linus Walleij wrote: > > On Mon, Aug 2, 2021 at 5:45 PM Martin Guy wrote: > > > > was removed from gcc in its 4.8 release in 2012. > > > > I was sad about that, as I had managed to get it working correctly in > > 4.2 4.3 and 4.4. > > Unfortunately the GCC ARM maintainer at the time was paid by ARM, and > > they had no interest in it, as I gather the ARM-Cirrus partnership > > ended up disappointingly. > > Political issues aside, have you considered contributing support > to LLVM instead? > > It currently doesn't even support ARMv4 AFAIK but reportedly > has an easier to use and maintain back-end. (I do not know if > this is true, I just browsed this: > https://llvm.org/docs/WritingAnLLVMBackend.html ) > Current ARM Targets are here: > https://github.com/llvm/llvm-project/tree/main/llvm/lib/Target/ARM > And they have a very clear and straight-forward developer policy: > https://llvm.org/docs/DeveloperPolicy.html > > If ARMv4 support could be added to LLVM, that would solve > a lot of my headaches for ARM32, where we have things like > SA110 being actively maintained. I think for ARMv4 support, the only thing we need from llvm is to have R_ARM_V4BX relocations, and for lld to support the --fix-v4bx switch that turns 'bx' instructions into 'mov' when those relocations are found. This is something that we have previously discussed with the llvm developers and that may easily happen. For the Crunch support, I don't think it's worth spending any effort on adding that to llvm. If there are any remaining users, they have probably stopped upgrading their user space long ago (to be confirmed). The SoC itself has been "not recommended for new design" since 2019, so we are unlikely to see new users of the platform in the future, and I think existing users are equally unlikely to move from softfp to crunch even if they have the option. Arnd _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel