UEFI Unified Kernel Image for Debian Installer on riscv64

On the riscv64 port, the default boot method is UEFI, with U-Boot typically used as the firmware. This approach aligns more closely with other architectures, which avoid developping riscv64 specific code. For advanced users, booting using U-Boot and extlinux is possible, thanks to the kernel being built with CONFIG_EFI_STUB=y.

The same applies to the Debian Installer, which is provided as ISO images in various sizes and formats like on other architectures. These images can be put on a USB drive or an SD-card and booted directly from U-Boot in UEFI mode. Some users prefer to use the netboot "image", which in practice consists of a Linux kernel, an initrd, plus a set of Device Tree Blob (DTB) files.

However, booting this in UEFI mode is not straightforward, unless you use a TFTP server, which is also not trivial. Less known to users, there is also a corresponding mini.iso image, which contains all the above plus a bootloader. This offers a simpler alternative for installation, but depending on your (vendor) U-Boot version this still requires to go through a media.

Systemd version 257-rc2 comes with a great new feature, the ability to include multiple DTB files in a single UKI (Unified Kernel Image) file, with systemd-stub automatically loading the appropriate one for the current hardware. A UKI file combines a UEFI boot stub program, a Linux kernel image, an optional initrd, and further resources in a single UEFI PE file. This finally solves the DTB problem in the UEFI world for distributions, as a single image can work on multiple boards.

Building upon this, debian-installer on riscv64 now also creates a UEFI UKI mini.efi image, which contains systemd-stub, a Linux kernel, an initrd, plus a set of Device Tree Blob (DTB) files. Using this image also ensures that the system is booted in UEFI mode. Booting it with debian-installer is as simple as:

load mmc 0:1 mini.efo $kernel_addr_r # (can also be done using tftpboot, wget, etc.)
bootefi $kernel_addr_r

Additional parameters can be passed to the image using the U-Boot bootargs environment variable. For instance, to boot in rescue mode:

setenv bootargs "rescue/enable=true"

AI crawlers should be smarter

It would be fantastic if all those AI companies dedicated some time to make their web crawlers smarter (what about using AI?). Noawadays most of them still stupidly follow every link on a Git frontend.

Hint: Changing the display options does not provide more training data!

Welcome Debian riscv64

After many years of effort, I am happy to announce that Debian riscv64 is now an official architecture!

This milestone is not the end of the journey but rather the beginning of a new one: the port will need to be rebootstrapped in the official archive, build daemons will have to be reinstalled and handed over to DSA, many bugs will need to be fixed. If everything goes well, the architecture will eventually be released with Trixie. Please note that this process will be long and will span several months.

I would like to take this opportunity to thanks everyone who contributed to this significant milestone, including individuals and Debian teams, as well as the organizations and companies that provided us with resources (by rough chronological order): MIT CSAIL, Sifive, Mullvad, tetaneutral.net, OSU Open Source Lab, Microchip, BeagleBoard.org Foundation, RISC-V international, PLCT Lab (ISCAS), StarFive, and Metropolitan Area Network Darmstadt.

Goodbye Debian GNU/kFreeBSD

Over the years, the Debian GNU/kFreeBSD port has gone through various phases. After many years of development, it was released as technology preview with the release of Squeeze and eventually became an official architecture with the release of Wheezy. However it ceased being an official architecture a couple of years later with the release of Jessie, although a jessie-kfreebsd suite was available in the official archive. Some years later, it was moved to the debian-ports archive, where it slowly regressed over the years. The development totally has now been stopped for over a year, and the port has been removed from the debian-ports archive. It's time to say it goodbye!

I feel a touch of nostalgia as I was deeply involved in the Debian GNU/kFreeBSD port for nearly a decade, starting in 2006. There are many different reasons to like GNU/kFreeBSD ranging from political to technical considerations. Personally, I liked the technical aspect, as the FreeBSD kernel, at that time, was ahead of the Linux kernel in term of features: jails, ZFS, IPv6 stateful firewalling, and at a later point superpages. That said it was way behind for hardware support and to the best of my knowledge this remains unchanged. Meanwhile, the Linux kernel development accelerated in the latter stages of the 2.6.x series, and eventually closed the feature gap. At some point, I began to lose interest, and also to lack time, and slowly stepped away from its development.

Backup server upgraded to Bookworm

A few months ago, I switched my backup server to an ODROID-M1 SBC. It uses a RK3568 SoC with a quad-core Cortex-A55 and AES extensions (useful for disk encryption), and I added a 2 TB NVME SSD to the M2 slot. It also has a SATA connector, but the default enclosure does not have space for 2.5" drives. It's not the fastest SBC, but it runs stable and quite well as a backup server, and it's fanless, and low-power (less than 2 W idle). The support for the SoC has been added recently to the Linux kernel (it's used by various SBC), however the device tree for the ODROID-M1 was missing, so I contributed it based on the vendor one, and also submitted a few small fixes.

All the changes ended in the Bookworm kernel, and with the Bookworm release approaching, I decided it was the good moment to upgrade it. It went quite well, and now I can enjoy running dist-upgrade like on other stable servers without having to care about the kernel. I am currently using Borg as a backup software, but the upgrade also gave access to a newer Restic version supporting compression (a must have for me), so I may give it a try.

New website, or kind of...

For over 15 years, I've hardly made any updates to my website, and it remains low on my priority list. So I made a radical decision to replace it entirely with my blog. The content of the website has been reduced to just two additional pages.

But nothing has been lost: nowadays, Wikipedia is a much better platform for sharing knowledge than random websites. And it happens that they already cover all that was on my website about subaquatic diving in French. They also offer a multitude of resources in electronics, including the topics that were on my website: LCD displays, I²C bus, barcodes, parallel ports, serial ports, and DCF77 reception.

Finally if you're in need of Debian QEMU images for various architectures, I recommend the Debian Quick Image Baker pre-baked images page instead.

riscv64 porterbox

For quite some time, many people asked for a riscv64 porterbox. Now we've got one called debian-riscv64-porterbox-01.debian.net.

A big thanks to SiFive for providing the HiFive Unmatched board and OSUOSL for assembling the hardware and hosting it.

GNU libc 2.34 in unstable

The GNU libc version 2.34 has just been accepted into unstable. Getting it ready has been more challenging than other versions, as this version integrates a few libraries (libpthread, libdl, libutil, libanl) into libc. While this is handled transparently at runtime, there are a few corner cases at build time:

  • For backwards compatibility, empty static archives (e.g. libpthread.a) are provided, so that the linker options keep working. However a few cmake files shipped in some packages still reference the path to the shared library symlink (e.g. libpthread.so) which is now removed.

  • A few symbols have also been moved from libresolv to libc and their __ prefix removed. While compatibily symbols are provided in the shared library for runtime compatiblity, this does not work at link time for static libraries referencing this symbol.

The next challenge is to get it migrating into testing!

For the adventurous persons, GNU libc 2.35 is now available in experimental. And as people keep asking, the goal is to get the just released GNU libc 2.36 into Bookworm.

James Webb Space Telescope launched!

The long awaited James Webb Space Telescope has finally been successfully launched today. It is a Xmas gift for many people who have been waiting for it for many years.

On a more personal side, I am happy and proud to have contributed to a tiny part of a tiny piece of software of this huge project over the last 15 years: the Instrument Performance Simulator of the NIRSpec instrument.

10 years ago...

I joined the Debian GNU libc team and did my first glibc upload. At that time source-only upload were far from existing, and I was using a HP 9000 model 715/80 HPPA workstation for my Debian builds.

Still it seems to me like yesterday.