From: Vincent Mailhol <mailhol@kernel.org>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@kernel.dk>, Davidlohr Bueso <dave@stgolabs.net>,
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Subject: Re: [PATCH 00/19] init: discoverable root partitions, a.k.a. an omittable "root=" cmdline option
Date: Mon, 15 Jun 2026 22:33:11 +0200 [thread overview]
Message-ID: <131a450f-f9c6-464c-8e4e-a4c7a29fb5de@kernel.org> (raw)
In-Reply-To: <20260615170432.GW2636677@ZenIV>
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 -- §16.2 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
prev parent reply other threads:[~2026-06-15 20:33 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-15 16:08 [PATCH 00/19] init: discoverable root partitions, a.k.a. an omittable "root=" cmdline option Vincent Mailhol
2026-06-15 16:09 ` [PATCH 19/19] docs: document discoverable root partitions Vincent Mailhol
2026-06-15 17:04 ` [PATCH 00/19] init: discoverable root partitions, a.k.a. an omittable "root=" cmdline option Al Viro
2026-06-15 20:33 ` Vincent Mailhol [this message]
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