View source for RISC-V

{{Expansion}}<!-- TODO: write preface -->
== Supported devices ==

Table legend:
* SoC - https://en.wikipedia.org/wiki/System_on_a_chip
* ISA - https://en.wikipedia.org/wiki/Instruction_set_architecture

=== Upstream (NixOS) supported devices ===

NixOS has no official support for riscv64-linux architecture on the nixpkgs-unstable and stable channel.

<!--
Order for the device table is:
 * By manufacturer name, alphabetical.
 * By release date, chronological (older first).
-->
<!-- TODO
{|class="table"
!width="2%"| Manufacturer
!width="2%"| Board
!width="2%"| SoC
!width="1%"| ISA
!width="2%"| CPU
!width="1%"| RAM
!width="2%"| Storage
|-
| —
| —
| —
| —
| —
| —
| —
|}
-->

=== Community supported devices ===

<!--
Order for the device table is:
 * By manufacturer name, alphabetical.
 * By release date, chronological (older first).
-->
<div class="table">
{|class="table"
!width="2%"| Manufacturer
!width="2%"| Board
!width="2%"| SoC
!width="1%"| ISA
!width="2%"| CPU
!width="2%"| RAM
!width="2%"| Storage
|-
| StarFive
| [[NixOS_on_RISCV/VisionFive|StarFive VisionFive]]
| JH7100
| RV64GC
| 2× SiFive U74 @ 1.5 GHz
| 8GB LPDDR4
| microSD
|-
| StarFive
| [[NixOS_on_RISCV/VisionFive_2|StarFive VisionFive 2]]
| JH7110
| RV64GC
| 4× SiFive U74 @ 1.5 GHz
| 2GB/4GB/8GB LPDDR4
| microSD, eMMC, M.2 M-Key
|}
</div>

==== Special Devices ====

It is possible to emulate a RISC-V platform with QEMU. Programs may occasionally crash on QEMU with a segmentation fault despite working on native RISC-V hardware.<ref>[https://github.com/NixOS/nixpkgs/issues/300550 Nixpkgs #300550]</ref><ref>[https://github.com/NixOS/nixpkgs/issues/300618 Nixpkgs #300618]</ref>

<div class="table">
{|class="table"
!width="2%"| Manufacturer
!width="2%"| Board
!width="2%"| SoC
!width="2%"| ISA
!width="2%"| CPU
!width="2%"| RAM
!width="2%"| Storage
|-
| QEMU
| <!-- [[NixOS_on_RISCV/QEMU|QEMU]] -->
| —
| Anything QEMU supports
| Anything QEMU supports
| Anything QEMU supports
| Anything QEMU supports
|}
</div>

== Installation ==

=== Getting the installer ===

<!-- TODO
==== UEFI iso ====
-->

==== SD card images (SBCs and similar platforms) ====

For <code>riscv64</code> it is possible to download images from the community.

* [https://github.com/zhaofengli/nixos-riscv64 Hifive Unmatched]
* [https://github.com/zhaofengli/nixos-riscv64 VisionFive 1]
* [https://github.com/NickCao/nixos-riscv VisionFive 2]
* [https://sr.ht/~fgaz/nixos-star64 STAR64]
* [https://github.com/ryan4yin/nixos-licheepi4a Lichee Pi 4A]

Build or download the image.

If the image has the extension <code>.zst</code>, it will need to be decompressed before writing to installation device. Use <code>nix-shell -p zstd --run "unzstd <img-name>.img.zst"</code> to decompress the image.

<!-- TODO
=== Installation steps ===
-->

== Binary cache ==
Example configuration snippet which can be used to add a third-party binary cache with RISCV support<syntaxhighlight lang="nix">nix.settings = {
  substituters = [
    "https://cache.ztier.in" # only nixos-unstable
  ];
  trusted-public-keys = [
    "cache.ztier.link-1:3P5j2ZB9dNgFFFVkCQWT3mh0E+S3rIWtZvoql64UaXM="
  ];
  experimental-features = [
    "nix-command"
    "flakes"
  ];
};</syntaxhighlight>Known third-party binary caches with RISCV support:
* [https://github.com/misuzu/nixos-vf2/blob/master/flake.nix#L3 misuzu] (only for nixos-unstable)

== NixOS Support ==

All RISC-V platforms are experimental for the time being.

There is a dedicated room for the upstream effort on Matrix, 
[https://matrix.to/#/#riscv:nixos.org matrix:r/riscv:nixos.org].

=== Awaiting upstream RISC-V support ===

* [https://github.com/LuaJIT/LuaJIT/issues/628 LuaJIT]
* [https://github.com/adoptium/temurin-build/issues/2726#issuecomment-1661380917 OpenJDK]
* [[RISC-V/GHC| GHC]]
* [https://bugs.kde.org/show_bug.cgi?id=468575 Valgrind]

== Resources ==

* https://wiki.riscv.org/display/HOME/Language+Runtimes
* https://github.com/NixOS/nixos-hardware

=== Subpages ===

The following is a list of all sub-pages of the ''NixOS on RISC-V'' topic.

{{Special:PrefixIndex/NixOS_on_RISCV/ |hideredirects=1 |stripprefix=1}}


The following is a list of all sub-pages of the ''Meetings/RISC-V''.

{{Special:PrefixIndex/Meetings/{{FULLPAGENAME}}/ |hideredirects=1 |stripprefix=1}}

== References ==