riscv64 is now upstream Debian architecture

[dkurt]

move dotnet/runtime#96349

https://wiki.debian.org/RISC-V#Package_repository

sudo ./eng/common/cross/build-rootfs.sh riscv64 sid --rootfsdir ./riscv64-rootfs

To double check:

• The right tests are in and and the right validation has happened. Guidance: https://github.com/dotnet/arcade/tree/main/Documentation/Validation

[dkurt]

@am11, please review

[am11]

@dkurt, looks good, thanks!

I tested it in dotnet prerequisites docker image and getting the following error:

$ docker run --rm -it mcr.microsoft.com/dotnet-buildtools/prereqs:ubuntu-22.04-cross-riscv64
$ git clone https://github.com/dkurt/arcade -b dkurt/update_riscv64_rootfs
$ cd arcade
$ ./eng/common/cross/build-rootfs.sh riscv64 sid --rootfsdir ./riscv64-rootfs
W: Cannot check Release signature; keyring file not available /usr/share/keyrings/debian-archive-keyring.gpg
E: Keyring-based check was requested; aborting accordingly

Looks like we will also need to update https://github.com/dotnet/dotnet-buildtools-prereqs-docker/blob/b9b1ed5784f888a400d32dcec7f4d4978e703c83/src/ubuntu/22.04/crossdeps/Dockerfile#L53. Could you take a look what needs updating there? Otherwise, the next build will fail in that repo if we merge this.

It may not be obvious how that repository builds, but for local testing, we can use pwsh build.ps1 -DockerfilePath "*ubuntu/22.04/cross/riscv64*" on linux/osx/win machines with powershell and docker installed. You can also leave the testing for CI (which runs when we ope the PR in that repo).

[dkurt]

@am11, thanks, with dotnet/dotnet-buildtools-prereqs-docker#945 it's working.