RISC-V Linux Tier 2 Host support

[tblah]

Proposal

Support riscv64gc-unknown-linux-gnu hosts at Tier 2. The Tier 2 support currently advertised on rust-forge is only for cross compilation.

• PR adding a builder
• Infrastructure team approval
• PR adding a testing image
• PR adding RISC-V notification group

Mentors or Reviewers

@nikomatsakis

Process

The main points of the Major Change Process is as follows:

• File an issue describing the proposal.
• A compiler team member or contributor who is knowledgeable in the area can second by writing @rustbot second.
  • Finding a "second" suffices for internal changes. If however you are proposing a new public-facing feature, such as a -C flag, then full team check-off is required.
  • Compiler team members can initiate a check-off via @rfcbot fcp merge on either the MCP or the PR.
• Once an MCP is seconded, the Final Comment Period begins. If no objections are raised after 10 days, the MCP is considered approved.

You can read more about Major Change Proposals on forge.

Comments

This issue is not meant to be used for technical discussion. There is a Zulip stream for that. Use this issue to leave procedural comments, such as volunteering to review, indicating that you second the proposal (or third, etc), or raising a concern that you would like to be addressed.

[rustbot]

This issue is not meant to be used for technical discussion. There is a Zulip stream for that. Use this issue to leave procedural comments, such as volunteering to review, indicating that you second the proposal (or third, etc), or raising a concern that you would like to be addressed.

[nikomatsakis]

OK, I'm not sure the best way to make approvals for Tier 2, but I propose that we go with FCP for now. To that end, I would like to propose to @rust-lang/compiler that we elevate RISC-V Linux to Tier 2 support. This would mean that we would check that it continues to build and that we can build it not only in cross-compiling mode but also on a RISC-V system, self-hosted.

The @rust-lang/infra team already gave their assent here. We have a proposed notification group of folks that would help with maintenance.

Moving to Tier 2 is certainly not irreversible, but it will mean that we distribute binaries with rustup, so withdrawing support would be quite noticeable. The main risk I see is that if we start getting more RISC-V specific bug reports, it will be hard for us to reproduce: but we're not committed to support at this tier, and the notification group should help with resolving such issues.

@rfcbot fcp merge

[rfcbot]

Team member @nikomatsakis has proposed to merge this. The next step is review by the rest of the tagged team members:

• @eddyb
• @estebank
• @matthewjasper
• @nagisa
• @nikomatsakis
• @oli-obk
• @petrochenkov
• @pnkfelix
• @varkor
• @wesleywiser

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

See this document for info about what commands tagged team members can give me.

[rfcbot]

🔔 This is now entering its final comment period, as per the review above. 🔔

psst @nikomatsakis, I wasn't able to add the final-comment-period label, please do so.

[rustbot]

This issue is not meant to be used for technical discussion. There is a Zulip stream for that. Use this issue to leave procedural comments, such as volunteering to review, indicating that you second the proposal (or third, etc), or raising a concern that you would like to be addressed.

[rustbot]

This issue is not meant to be used for technical discussion. There is a Zulip stream for that. Use this issue to leave procedural comments, such as volunteering to review, indicating that you second the proposal (or third, etc), or raising a concern that you would like to be addressed.