Re: [gentoo-dev] Progress of the Gentoo/LoongArch port, and question on upstreaming procedure

[Alexey 'Alexxy' Shvetsov]

Hi!

Its interesting thing. Is there a possibility to get LoongArch hw outside of 
China?

В письме от суббота, 1 января 2022 г. 20:28:16 MSK пользователь WANG Xuerui 
написал:
> Hi everyone,
>
> I'm the guy who previously announced the Gentoo/LoongArch port [1];
> since that post, some nice progress has been made, and here's a heads-up
> and a procedural question regarding how to continue work upstream.
>
>
> ## Progress of the port
>
> After some minimal forking and tweaking, it's already possible to build
> working stage3 tarballs with catalyst;
> with quick-and-dirty catalyst[2] and genkernel[3] patches, even working
> installation CDs can be built (confirmed by LiveUSB-making and booting
> on real 3A5000 hardware).
> The built stages and installation CD images are already available in
> several mirrors like [4] or [5].
>
> The toolchain development of Loongson has gone more-or-less quiet
> lately, and many projects (eselect, icu, systemd, etc.) have already had
> releases that contain LoongArch bring-up changes, so it's time to push
> more things upstream (in this case, the main gentoo.git repo).
>
>
> ## How to test this?
>
> The necessary changes are all brewing in the loongson-overlay[6], which
> is available via layman (`sudo layman -a loongson`). You'll need this
> for the loong profile and toolchain patches.
>
> The stages can be tested with QEMU linux-user emulation, if you don't
> have the LoongArch hardware;
> but the LoongArch target is not upstream yet, so you'll have to compile
> Loongson's fork ([7]; qemu-devel threads [8] [9]) yourself. The
> necessary binfmt-misc declaration is like this (remove all whitespaces
>
> and newlines before using):
>  > :loongarch64:M::
>  > \x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x02\x01:
>  > \xff\xff\xff\xff\xff\xff\xff\xfc\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff
>
>  > \xff\xff:/usr/local/bin/qemu-loongarch64:
> You can use your favorite way to set up this (manually, via rc-scripts,
> via systemd-binfmt.service, whatever), replacing the interpreter path to
> suit your setup, then just proceed like every chroot.
>
> Inside the chroot, you need to `git clone` the loongson-overlay, add it
> to /etc/portage/repos.conf, and fix the profile symlink; after that you
> should be able to emerge packages as usual. Keywords are mostly missing,
> so you may use ACCEPT_KEYWORDS=~riscv or something similar to get
> through, in case everything is masked and not package.accept_keywords-ed.
>
> Note that their system emulation is currently in a worse state than
> linux-user (horribly slow and dependent on prebuilt firmware blob),
> according to review comments, so you may as well ignore the installation
> CDs for now.
>
>
> ## Problem regarding further upstream work
>
> As described above, there is already some nice progress, but a
> procedural problem still remains: every new architecture needs a backing
> project and arch team [10], yet I'm not a Gentoo dev and it's unclear if
> any Gentoo dev would be interested in such a niche architecture with
> limited hardware availability outside China, so we may get stuck in this
> state for an extended period.
>
> Any suggestion is welcome; and thank you for your attention.
>
>
> Regards,
> WANG "xen0n" Xuerui
>
>
> [1]:
> https://archives.gentoo.org/gentoo-dev/message/ef0b1812e9b66cdf5978ecc2ad4ed
> a4e [2]: https://github.com/xen0n/catalyst/tree/3.0.20-for-loong
> [3]: https://github.com/xen0n/genkernel/tree/loong
> [4]: https://mirrors.tuna.tsinghua.edu.cn/loongson/gentoo/experimental/
> [5]: https://mirrors.bfsu.edu.cn/loongson/gentoo/experimental/
> [6]: https://github.com/xen0n/loongson-overlay
> [7]: https://github.com/loongson/qemu/tree/tcg-dev
> [8]:
> https://patchew.org/QEMU/1638610165-15036-1-git-send-email-gaosong@loongson.
> cn/ [9]:
> https://patchew.org/QEMU/1638619645-11283-1-git-send-email-yangxiaojuan@loon
> gson.cn/ [10]:
> https://projects.gentoo.org/council/meeting-logs/20180114-summary.txt


-- 
Best regards,
Alexey 'Alexxy' Shvetsov