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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 47780CD98CE for ; Mon, 15 Jun 2026 20:33:29 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4gfMJk3HGHz3brl; Tue, 16 Jun 2026 06:33:26 +1000 (AEST) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip="2600:3c0a:e001:78e:0:1991:8:25" ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1781555606; cv=none; b=KajfVWhTn+ofS6M3YZt9JYqO3wrjvzJ60FO81reE+zdP2yJ5EhGm+Iu5yykrkOZwx0w+OZPi8kWVNIawdhtsnUuuZQH8vzpDEBg4Mb7zanpr/2BIrSRQN3maDP/p2y5XsI+2EVb9oem9Ed/BtaWbUydIoQ7jo4fMONkd74tzPs+iMM+anRrXqpCGvEVLg8aLbefO4pWHrHJlQubr/vWfe4fp1ZKqCZ/Ge5xtX5oyJhsra6KljgeQw9O6Mkr9kPUl7zQT0RY0Z3fFoqKZ90tLzRbpdO0sWUSwwr8sjdmo0hZdwPE9hrdgNjzjyGNgheA0hkzscj/vDgX62hftMkAOUQ== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1781555606; c=relaxed/relaxed; bh=as7Ogfoc/AyskAy2+J9eXyhxUhgDui71XAx+CHT5Mew=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Xv23uOpAJCO8bNsa2hJ3J0jr5ocCwAfdlL3sR5rqmBh3i09q4svwZnn5nBhH0o39TV2Nz4Q60g7tp3DAb0DaZBI9AnTPdw11GB7oodtActp5qIPBPPX35AyD4nqttmb2mUZM16ApOz3ufruIQ07OVQ1YMt8gMmWow2enbUOsSqRjfniOyn8ScxETUEQ8PtDc8NZMmHpqDJxF68u9to2qE+jWgFkm18C4SQBet4y8AB/10iRk7JDV+ZQCgiwqoZmCoR2+uZja6S5l4rC2xuBTbXfi5ktxlHkW0ubqUblxaa05XsJPrs0QVLboyh0B+EZva+ys5KZqIk4SzmxK6V1UXQ== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=kernel.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=E86R2Mc0; dkim-atps=neutral; spf=pass (client-ip=2600:3c0a:e001:78e:0:1991:8:25; helo=sea.source.kernel.org; envelope-from=mailhol@kernel.org; receiver=lists.ozlabs.org) smtp.mailfrom=kernel.org Authentication-Results: lists.ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=kernel.org Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=E86R2Mc0; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=2600:3c0a:e001:78e:0:1991:8:25; helo=sea.source.kernel.org; envelope-from=mailhol@kernel.org; receiver=lists.ozlabs.org) Received: from sea.source.kernel.org (sea.source.kernel.org [IPv6:2600:3c0a:e001:78e:0:1991:8:25]) (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 4gfMJh4JSwz3brL for ; Tue, 16 Jun 2026 06:33:24 +1000 (AEST) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 77BF54360F; Mon, 15 Jun 2026 20:33:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D89131F000E9; Mon, 15 Jun 2026 20:33:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781555601; bh=as7Ogfoc/AyskAy2+J9eXyhxUhgDui71XAx+CHT5Mew=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=E86R2Mc0QLlmn6hDEj5MnafzRYyOh8VthGPhggOCVEqZ9xx+sywlJb7QXeIaMbEFA rvREbsI3Zv0iMBuDfYoDef4TgGcmk0gnzth2mBKPpYT5zfQfxZKaETEbxVznMvRfoH piXE10ylpTWfk/t+pECRYcy/iMGYN/iwRMhVbs6e5bPwfcEmSrgpliHOIWdD3C35KZ 3dd4XZnD7RANNMAcrkEHv2ZJgOVbQ7VfGmUoC1gB6jeJzKn1pSM0YTSpCEnNMVRUEO 3IE0flzeBTi4viwUUEYjyjwYKI+KhiEhnh6PLe1a+NU0sfU6WVODjevHGI2ZZiYcfX AyBnvEPDADOhQ== Message-ID: <131a450f-f9c6-464c-8e4e-a4c7a29fb5de@kernel.org> Date: Mon, 15 Jun 2026 22:33:11 +0200 X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 00/19] init: discoverable root partitions, a.k.a. an omittable "root=" cmdline option To: Al Viro Cc: Jens Axboe , Davidlohr Bueso , Christian Brauner , Jan Kara , linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-efi@vger.kernel.org, linux-fsdevel@vger.kernel.org, Richard Henderson , Matt Turner , Magnus Lindholm , linux-alpha@vger.kernel.org, Vineet Gupta , linux-snps-arc@lists.infradead.org, Russell King , linux-arm-kernel@lists.infradead.org, Catalin Marinas , Will Deacon , Huacai Chen , WANG Xuerui , loongarch@lists.linux.dev, Thomas Bogendoerfer , linux-mips@vger.kernel.org, "James E.J. Bottomley" , Helge Deller , linux-parisc@vger.kernel.org, Madhavan Srinivasan , Michael Ellerman , linuxppc-dev@lists.ozlabs.org, Paul Walmsley , Palmer Dabbelt , Albert Ou , linux-riscv@lists.infradead.org, Heiko Carstens , Vasily Gorbik , Alexander Gordeev , linux-s390@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Jonathan Corbet , Shuah Khan , linux-doc@vger.kernel.org References: <20260615-discoverable-root_partitions-v1-0-39c78fac42e2@kernel.org> <20260615170432.GW2636677@ZenIV> From: Vincent Mailhol Content-Language: en-US Autocrypt: addr=mailhol@kernel.org; keydata= xjMEZluomRYJKwYBBAHaRw8BAQdAf+/PnQvy9LCWNSJLbhc+AOUsR2cNVonvxhDk/KcW7FvN JFZpbmNlbnQgTWFpbGhvbCA8bWFpbGhvbEBrZXJuZWwub3JnPsKZBBMWCgBBFiEE7Y9wBXTm fyDldOjiq1/riG27mcIFAmdfB/kCGwMFCQp/CJcFCwkIBwICIgIGFQoJCAsCBBYCAwECHgcC F4AACgkQq1/riG27mcKBHgEAygbvORJOfMHGlq5lQhZkDnaUXbpZhxirxkAHwTypHr4A/joI 2wLjgTCm5I2Z3zB8hqJu+OeFPXZFWGTuk0e2wT4JzjgEZx4y8xIKKwYBBAGXVQEFAQEHQJrb YZzu0JG5w8gxE6EtQe6LmxKMqP6EyR33sA+BR9pLAwEIB8J+BBgWCgAmFiEE7Y9wBXTmfyDl dOjiq1/riG27mcIFAmceMvMCGwwFCQPCZwAACgkQq1/riG27mcJU7QEA+LmpFhfQ1aij/L8V zsZwr/S44HCzcz5+jkxnVVQ5LZ4BANOCpYEY+CYrld5XZvM8h2EntNnzxHHuhjfDOQ3MAkEK In-Reply-To: <20260615170432.GW2636677@ZenIV> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 15/06/2026 at 19:04, Al Viro wrote: > On Mon, Jun 15, 2026 at 06:08:56PM +0200, Vincent Mailhol wrote: > >> Tested with GRUB, which implements the LoaderDevicePartUUID EFI variable >> in its bli module [3]. With this, I was able to boot a kernel with a >> completely empty cmdline and no initrd. >> >> [1] The Discoverable Partitions Specification (DPS) >> Link: https://uapi-group.org/specifications/specs/discoverable_partitions_specification/ >> >> [2] systemd-gpt-auto-generator >> Link: https://www.freedesktop.org/software/systemd/man/latest/systemd-gpt-auto-generator.html >> >> [3] GRUB -- ยง16.2 bli >> Link: https://www.gnu.org/software/grub/manual/grub/html_node/bli_005fmodule.html > > So what does that thing, tied to EFI as it is, have to do with architectures where > * firmware is rather unlike EFI I made CONFIG_DPS_ROOT_AUTO_DISCOVERY depend on CONFIG_EFI for this reason. > * firmware wouldn't know what to do with GPT > * GRUB is *not* ported to, let alone used > such as, say it, the very first one mentioned at your [1]? Fair point. I just did: $ git grep "^config EFI$" arch/arm/Kconfig:config EFI arch/arm64/Kconfig:config EFI arch/loongarch/Kconfig:config EFI arch/riscv/Kconfig:config EFI arch/x86/Kconfig:config EFI Anything not in this list is dead code at the moment. > Or is that conditional upon "if anyone wants to design replacement firmware > for those, and if they agree to follow our wishlist"? No, it was just an oversight from my side. I will just keep arm, arm64, loongarch, riscv and x86 in my v2. Yours sincerely, Vincent Mailhol