No description
Find a file
Mathieu Benoit 94c74eb691 [ADD] stage 2: a chroot that builds
Stage 1 is done and its output is provably wrong in nine places: binaries
asking for libgpgme.so.11, libnettle.so.8, libicuuc.so.76 and six more at the
HOST's soname versions. Stage 2 dissolves all nine by rebuilding each package
against what the repository actually ships.

The constraint that shapes it: pacman cannot run inside the stage-1 rootfs,
because libalpm was linked against the host's gpgme. So the rootfs is
populated from OUTSIDE, with the host's pacman and --root, and the chroot is
used only to build. That is not a workaround, it is the order the problem has
-- stage 2's own output is the first pacman that will run on the target.

Five packages were added to stage 1 for this, and the resolver could never
have named them: nothing DEPENDS on fakeroot or bison, they are simply what a
build needs to happen. makepkg refuses to run as root, so the chroot carries a
user with the host's uid -- a bind mount keeps the numeric owner, and a
different uid inside could not write $srcdir.

The smoke test separates hard failures from known drift. makeinfo fails
because texinfo was built against the host's perl; that is what stage 2
repairs, so refusing to start over it would refuse to run the fix.

--- FR ---

L'étage 1 est terminé et sa sortie est démontrablement fausse en neuf points :
des binaires réclamant libgpgme.so.11, libnettle.so.8, libicuuc.so.76 et six
autres, aux versions de soname de l'HÔTE. L'étage 2 les dissout tous les neuf
en reconstruisant chaque paquet contre ce que le dépôt livre réellement.

La contrainte qui le façonne : pacman ne peut pas tourner dans le rootfs
d'étage 1, libalpm ayant été lié contre le gpgme de l'hôte. Le rootfs est donc
peuplé depuis l'EXTÉRIEUR, avec le pacman de l'hôte et --root, et le chroot ne
sert qu'à bâtir. Ce n'est pas un contournement mais l'ordre qu'a le problème :
la sortie de l'étage 2 est le premier pacman qui tournera sur la cible.

Cinq paquets ont rejoint l'étage 1 pour cela, et le résolveur n'aurait jamais
pu les nommer : rien ne DÉPEND de fakeroot ni de bison, ils sont simplement ce
qu'il faut pour qu'une compilation ait lieu. makepkg refuse de tourner en
root, le chroot porte donc un utilisateur avec l'uid de l'hôte — un bind mount
conserve le propriétaire numérique, et un uid différent ne pourrait pas
écrire $srcdir.

Le smoke test sépare les échecs durs des dérives connues. makeinfo échoue
parce que texinfo a été bâti contre le perl de l'hôte ; c'est précisément ce
que l'étage 2 répare, donc refuser de démarrer pour cela serait refuser de
lancer le correctif.

Assisted-by: Claude Opus 5
2026-08-19 08:30:49 -04:00
.github/workflows making the house a home 2026-01-27 23:26:31 +01:00
arch-kernel making the house a home 2026-01-27 23:26:31 +01:00
boot making the house a home 2026-01-27 23:26:31 +01:00
patches [FIX] gcc: two defects only a chroot could find 2026-08-19 08:30:49 -04:00
scripts [ADD] stage 2: a chroot that builds 2026-08-19 08:30:49 -04:00
.env.example full boot with systemd 2025-06-05 12:32:34 +02:00
.gitignore making the house a home 2026-01-27 23:26:31 +01:00
CODEOWNERS making the house a home 2026-01-27 23:26:31 +01:00
Containerfile making the house a home 2026-01-27 23:26:31 +01:00
LICENSE use arch kernel patches 2025-06-02 21:53:33 +02:00
Makefile making the house a home 2026-01-27 23:26:31 +01:00
README.md making the house a home 2026-01-27 23:26:31 +01:00
TODO.md [FIX] test-chroot: an audit that classifies, and one that was wrong 2026-08-19 06:40:50 -04:00

Arch Linux s390x

A port of Arch Linux to IBM s390x mainframe architecture with systemd support.

Boots a full Arch Linux system on IBM mainframes (or QEMU s390x emulation) using a hybrid build: cross-compilation for the kernel, native s390x compilation on z/VM for userspace.

Quick Start

make container        # build dev container (first time)
cp .env.example .env  # configure z/VM access
make all              # build kernel + initramfs + systemd
make test-systemd     # boot it

What Works

  • Arch Linux kernel 6.18.6-arch1 with Arch patches, cross-compiled
  • Initramfs via modified mkinitcpio
  • Static busybox built natively on z/VM, 2.3MB
  • Root filesystem with ext4, switch_root to real rootfs
  • Systemd as PID 1

Pacman, bash, and GNU coreutils are not yet ported.

Build System

The build uses two tiers:

Cross-compilation (x86_64 host): Kernel is built in a Fedora 43 container with s390x-linux-gnu-gcc. Initramfs is generated with a patched mkinitcpio that handles cross-architecture binary injection.

Native compilation (s390x z/VM): Busybox and systemd must be built on real s390x hardware. The z/VM system runs RHEL 9.6 with GCC 11.5.0. Scripts handle SSH deployment and retrieval automatically via .env configuration.