Since the first time I learned about the existence of RISC-V, I have been fascinated by it. I wanted to run operating systems on it, and try out software on the ISA.

In the beginning this was made possible by emulation, and the last years I treated myself with two physical pieces of RISC-V hardware. But these means of playing around with RISC-V had a thing in common; it was using the 64-bit version of the ISA (riscv64).

I also wanted to play around with the 32-bit variant of RISC-V. After looking around a bit on the internet I found some references for a Debian riscv32 port. But this is something I would have to do a lot of setup for myself, or use a downstream rootfs. I wanted to use an official rootfs built by the distribution maintainers themselves.

After searching some more I found out Gentoo offers “stage 3” tarballs for riscv32!

Now, how do you actually get a shell in this rootfs? The answer for this can be found in the ability for Podman to run images built for foreign architectures. It’s pretty simple from this point to get thins running if systemd-binfmt is installed and configured:

1. Download the Gentoo riscv32 stage 3 tarball from this page. I used the “musl-variant”. But other variants should also work.
2. Import the tarball as a container image, and change the entrypoint to a more powerful shell:

$ podman import --arch riscv32 --change ENTRYPOINT=/usr/bin/bash stage3-rv32_ilp32_musl-<$BUILD_DATE>.tar gentoo-riscv32

3. Actually run the image in a container:

$ podman run -it --rm --arch riscv32 gentoo-riscv32:latest 

That’s it! You’re now running riscv32 binaries, inside a Gentoo rootfs, using QEMU user mode emulation:

5468377bf688 / # arch
riscv32
5468377bf688 / # file /bin/bash
/bin/bash: ELF 32-bit LSB pie executable, UCB RISC-V, RVC, soft-float ABI, version 1 (SYSV), dynamically linked, interpreter /lib/ld-musl-riscv32-sf.so.1, stripped

As a bonus, let’s try installing fastfetch:

5468377bf688 / # emerge --sync
5468377bf688 / # emerge --ask app-misc/fastfetch

This only took 66 minutes on my laptop with a Intel Core Ultra 7 155U… But it works!