From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E69AA3B6C15; Mon, 15 Jun 2026 20:43:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781556235; cv=none; b=NVYzndRpDTaoz9vcooCKe2/hkseNP4lBg6+NYml9JZ16hQacJJubnmeX8DkChVuZXJQsR79bbDbKDO4QKt2gwV5Vqgd0UPG4fvklYE2HYyS9N2Fe7YIql3Q4DuVcab9WD4LJ3tepy4/UAZ8oe1J7jX2etk0Bbj1sW8zCxDQb+XY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781556235; c=relaxed/simple; bh=faFwjoN0gn80v9QqMuh2mJ76DSKcg+KCmO8Za4zFEdQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=iKakvP9p2OqT+bg94Kp5TeZfslm9ijLi9heIgQf7ThynyjkZv6MXWzKLSojUbYKFM8Ilev6eKNh12J8jESpr3iqwZHOxZCWJM4U9YbpVQuH8FauWtGifhU9Rc6kAl7tS1NWD8A5e6E32s0rfgvbJ8QtmTCvVqixaC3iCFMr8ZsI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=S9nA0vhD; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="S9nA0vhD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 492711F000E9; Mon, 15 Jun 2026 20:43:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781556234; bh=pAr0CezAnYbjsc5uzKsTNhtjW8ESmPALnRPgKDluIbA=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=S9nA0vhDxdupgcHbwB2JLHzDQ2Foz/U+lEYay6SGXpc21k+gF9cSVbZFiGnLkDmyH seRBOTTaN92A9/6ZDT6eDYu1wKhuDVok+mjhODT/ijI2tCNs38MRiJKw7xsVwWvLh5 6pW1z7ECVQBZKSADO9xjN/WqSSNb5gFeEgj1jj1xm742D+xJCkFc3sjeShnHg6dwDo 4sDxJLMnlENN71pyGTYkOTR9LiCcPUOuOPo9U3E3F9xR2xTRHNZuqosI0KepEKYVH5 B40niaAFhxysltgzI9N0LDzy489Y4Kdnle4jwCcK00OFBYSPnF1ysU/0lcq0j9OfQD Rft/70AOqbmmw== Message-ID: <1996618c-a6ab-497f-9c4e-33468e7802d4@kernel.org> Date: Mon, 15 Jun 2026 22:43:51 +0200 Precedence: bulk X-Mailing-List: linux-efi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 08/19] parisc: define DPS root partition type UUID To: Helge Deller , James Bottomley , Jens Axboe , Davidlohr Bueso , Alexander Viro , Christian Brauner , Jan Kara Cc: linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-efi@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-parisc@vger.kernel.org References: <20260615-discoverable-root_partitions-v1-0-39c78fac42e2@kernel.org> <20260615-discoverable-root_partitions-v1-8-39c78fac42e2@kernel.org> <0158c89cffd76c621607f66d1889ccc084754729.camel@HansenPartnership.com> <0290e66b-1da2-4706-ab28-2d47f164df08@gmx.de> 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: <0290e66b-1da2-4706-ab28-2d47f164df08@gmx.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 15/06/2026 at 22:27, Helge Deller wrote: > On 6/15/26 22:02, James Bottomley wrote: >> On Mon, 2026-06-15 at 18:09 +0200, Vincent Mailhol wrote: >>> DPS [1] assigns GPT partition type UUIDs to operating system >>> partitions. Root partitions use architecture-specific type UUIDs so >>> the OS can discover the intended root filesystem without relying on a >>> root=  cmdline option. >>> >>> Define DPS_ROOT_PARTITION_TYPE_UUID in asm/dps_root.h for parisc and >>> select ARCH_HAS_DPS_ROOT_PARTITION_TYPE_UUID. > > Vincent, first of all thank you for at least trying to including parisc > (and other > niche Linux ports) in the specification! (whatever the outcome is!) You are welcome. My personal interest is only x86_64 at the moment, but at least I tried to make it useful to the broader community! >>> [1] The Discoverable Partitions Specification (DPS) >>> Link: >>> https://uapi-group.org/specifications/specs/ >>> discoverable_partitions_specification/ >> >> How are you planning to make this work for parisc?  Some systems have a >> PALO boot partition (fdisk type 0xf0) but the more modern way is to >> place palo inside a hidden ext4 inode in /boot.  The way parisc IODC >> works is very similar to the way MSDOS boots with the palo location >> table in the first block so I theorize that would probably work for gpt >> partitions as well ... I'm just not sure anyone has tested it. >> >> However, to get this to work with PALO for auto discovery, you'd need >> palo patches to recognize the DPS UUID and no-one seems to have >> submitted anything to palo for this. > > Maybe it's not necessary that palo does this job? > palo could stay as is and load kernel and the initrd. > Then the kernel (or the scripts in initrd) could try to find the root > partition on it's own (and handle GPT discs). > > I even once started porting grub to parisc (which is currently on hold > because I'm busy with other stuff). If I ever finish it, having such a > mechanism/constant already in place is IMHO beneficial. You can see my answer to Alexander on the cover letter. This was an oversight. parisc does not have CONFIG_EFI to begin with, so the feature is just dead code there. I will remove parisc (and all other architectures which do not have a CONFIG_EFI) in v2. If someone wants to implement EFI support those architectures, only then, we can revisit this DPS topic for these architectures. Yours sincerely, Vincent Mailhol