Feature Request: Add Support for RISC-V (riscv64) Architecture

[eznix86]

With the rise of alternative CPU architectures following Apple's M series chips, RISC-V has gained significant traction.

I am currently using a Milk-V Duo S, which is based on the RISC-V architecture:

When attempting to use curl on this device (which runs BusyBox), I noticed that riscv64 is not currently supported.

Would it be possible to add support for this architecture? If this is not something that can be added directly, I would be happy to contribute, but I would appreciate any guidance on where to make the necessary updates. I am not very familiar with Rust, so any pointers on where to start would be helpful.

Thank you!

[ekzhang]

Interesting, which OS is it running? And what would you say would be the number of people using these devices -- I'd imagine it is mostly embedded systems currently or is it also used for servers / desktops?

You may want to check out this list https://doc.rust-lang.org/beta/rustc/platform-support.html

[eznix86]

For numbers of people there is no stats, but i can speculate, based on this video (https://youtu.be/rby8a_DsSYc) which has 64K views, let's say 5% of people bought it, which is 3200 devices sold minimum, then there are people like me who needs like 10 like those, so i could say it can vary from 3200 ~ 320 000 devices sold worldwide (also it mostly got sold out last time)

It uses a custom firmware :

[root@milkv-duo]~# uname -a
Linux milkv-duo 5.10.4-tag- #1 PREEMPT Thu Aug 1 14:12:58 CST 2024 riscv64 GNU/Linux

When cross-checking with milk-v docs, and rust docs you provide, it uses should be using riscv64gc-unknown-linux-musl

Milk V Duo S firmware releases page:
https://github.com/milkv-duo/duo-buildroot-sdk-v2/releases/ (milk v duo s has dual architecture, arm and riscv).

[ekzhang]

Nice! unfortunately the cross-compiler / linker toolchain I use https://github.com/messense/homebrew-macos-cross-toolchains doesn't have riscv64gc targets so that's sad. But maybe there's a way to do it with cross.

Want to try building with cross from a different computer (not the riscv one) and let me know what works? This is what I have for my freebsd build for instance, along with some config in Cross.toml

cross build --release --target x86_64-unknown-freebsd

[target.x86_64-unknown-freebsd]
pre-build = [
    "apt-get update",

    # Protobuf version is too outdated on the cargo-cross image, which is ubuntu:20.04.
    # "apt install -y protobuf-compiler",

    "apt install -y wget libarchive-tools",
    "mkdir /protoc",
    "wget -qO- https://github.com/protocolbuffers/protobuf/releases/download/v29.2/protoc-29.2-linux-x86_64.zip | bsdtar -xvf- -C /protoc",
    "mv -v /protoc/bin/protoc /usr/local/bin && chmod +x /usr/local/bin/protoc",
    "mkdir -p /usr/local/include/google/protobuf/",
    "mv -v /protoc/include/google/protobuf/* /usr/local/include/google/protobuf/",
    "rm -rf /protoc",
]

[ovidiuvio]

I've asked Claude Opus 4 to make a go port of the client. I've compiled that for various platforms. Works fine on my mips64 router.
If it helps, you can try the riscv64 binary from here: https://github.com/ovidiuvio/SSHXtend/releases/download/v0.4.1-sshxtend/sshxtend-go-linux-riscv64

It is a fork and has some changes, but it seems it still works fine with sshx.io

[eznix86]

Hi, Thanks @ovidiuvio on my risc64 I get those

failed to create controller: failed to open session: rpc error: code = Unavailable desc = connection error: desc = "error reading server preface: unexpected EOF"

and sometimes

failed to create controller: failed to open session: rpc error: code = Unavailable desc = connection error: desc = "error reading server preface: read tcp 192.168.8.94:55500->66.51.127.182:443: read: connection reset by peer

[ovidiuvio]

Hi, Thanks @ovidiuvio on my risc64 I get those

failed to create controller: failed to open session: rpc error: code = Unavailable desc = connection error: desc = "error reading server preface: unexpected EOF"

and sometimes

failed to create controller: failed to open session: rpc error: code = Unavailable desc = connection error: desc = "error reading server preface: read tcp 192.168.8.94:55500->66.51.127.182:443: read: connection reset by peer

Ok, seems there was a problem with tls connections in the go implementation:
ovidiuvio@97abf3a
New build here:
https://github.com/ovidiuvio/SSHXtend/releases/download/v0.4.1-o2-sshxtend/sshxtend-go-linux-riscv64

[ekzhang]

Did anyone try using cross as I suggested in #125 (comment)

No worries if not, I think that's probably the most promising approach also. Surprised that porting the whole thing to a new language with AI is easier than figuring out how to set cross-compilation flags in Rust (possibly also with AI?) 😓

[ovidiuvio]

@ekzhang I've tried to build it with cross for mips64 in january 2025 and spent a few good hours on that without much luck...

Opus 4 made the go port in 3 prompts ...🤷‍♂️

[eznix86]

Did anyone try using cross as I suggested in #125 (comment)

No worries if not, I think that's probably the most promising approach also. Surprised that porting the whole thing to a new language with AI is easier than figuring out how to set cross-compilation flags in Rust (possibly also with AI?) 😓

Well you are right, no way to build on mac os :( I spent 3 hours fighting. If @ovidiuvio version works, i think you could merge it to your project ?

[eznix86]

@ovidiuvio @ekzhang and @ovidiuvio implementation works!

• Current use case is for IoT, milkv-duo was 20KM away, had to swap tailscale ownership.