Reorganize userspace/ into base/ and tests/userspace/

[dburkart]

Closes #872

Summary

• Move base system crates (init, vibix_abi, vibix_libc, vibix_libc_defs, ld_vibix, lib) from userspace/ to base/
• Move test/demo binaries (hello, hello_dyn, std_hello, pjdfstest_runner, repro_fork, shell_pipeline) from userspace/ to tests/userspace/
• Update all path references: workspace Cargo.toml members, inter-crate path deps, xtask build paths, CI workflow paths, library/std vibix_abi dep, and RFC 0009 documentation

Test plan

• cargo xtask build — passes
• cargo xtask test — host unit tests + QEMU integration tests pass (blocking_sync::rwlock_concurrent_readers flake is preexisting blocking_sync rwlock test fails on main: readers serialised — rwlock didn't grant shared access #791)
• cargo xtask smoke — all 42 markers present

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 78c5bafa-b272-4531-9622-dcee6f7292dd

📥 Commits

Reviewing files that changed from the base of the PR and between 6bbab72 and 41876f4.

📒 Files selected for processing (3)

• docs/design/dst-478-investigation.md
• docs/repros/fork-loop.md
• xtask/src/main.rs

✅ Files skipped from review due to trivial changes (2)

• docs/design/dst-478-investigation.md
• docs/repros/fork-loop.md

🚧 Files skipped from review as they are similar to previous changes (1)

• xtask/src/main.rs

---

📝 Walkthrough

Walkthrough

This PR reorganizes the userspace/ directory by splitting it into base/ (for system components like init, vibix_abi, vibix_libc, ld_vibix) and tests/userspace/ (for test/demo binaries like hello, repro_fork, shell_pipeline). All workspace members, build paths, dependencies, CI triggers, and documentation references are updated to reflect the new structure.

Changes

Directory Structure Reorganization

Layer / File(s)	Summary
Workspace Declaration Cargo.toml, library/std/Cargo.toml, tests/userspace/hello_dyn/Cargo.toml	Workspace members migrate from userspace/* to base/* and tests/userspace/*. Root Cargo.toml updates members list and exclude paths. library/std dependency on vibix_abi changes from ../../userspace/vibix_abi to ../../base/vibix_abi. hello_dyn dependency on vibix_libc changes from ../vibix_libc to ../../../base/vibix_libc.
Build System Integration xtask/src/main.rs	All userspace build functions (build_userspace_init, build_userspace_hello, build_userspace_repro_fork, build_userspace_shell_pipeline, build_pjdfstest_runner, build_ld_vibix, build_userspace_hello_dyn) update linker script paths from userspace/*/link.ld to base/*/link.ld or tests/userspace/*/link.ld. Build manifest for std_hello relocates from userspace/std_hello/Cargo.toml to tests/userspace/std_hello/Cargo.toml. Musl dynamic linker embedded in initrd and ISO switches from userspace/lib/ld-musl-x86_64.so.1 to base/lib/ld-musl-x86_64.so.1. Unit tests for repro-fork read sources from updated paths.
CI Workflow Configuration .github/workflows/smoke-soak.yml	Path-based eligibility check for fork_exec_surface trigger updates from userspace/repro_fork/** to tests/userspace/repro_fork/** with accompanying comment adjustments.
Documentation Updates docs/RFC/0009-std-on-vibix.md, docs/design/dst-478-investigation.md, docs/repros/fork-loop.md	All path references are updated: userspace/vibix_abi/ → base/vibix_abi/, userspace/vibix_libc/ → base/vibix_libc/, userspace/repro_fork/ → tests/userspace/repro_fork/, userspace/lib/ld-musl-x86_64.so.1 → base/lib/ld-musl-x86_64.so.1, and userspace/init/ → base/init/.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• dburkart/vibix#521: Updates smoke-soak CI path filters and repository layout references for the repro-fork harness relocation from userspace/repro_fork to tests/userspace/repro_fork.
• dburkart/vibix#684: Migrates userspace artifacts (including shell_pipeline) into tests/userspace/ and updates Cargo/xtask/CI paths accordingly.
• dburkart/vibix#513: Introduces the repro_fork harness and linker configuration, which this PR subsequently relocates from userspace/ to tests/userspace/ and base/.

Poem

🐰 From userspace chaos, order takes flight,
Base and tests now split just right,
Init and libc find their way,
While fixtures hop to brighter day! 🚀

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely summarizes the main change: reorganizing userspace/ into two new directories (base/ and tests/userspace/).
Description check	✅ Passed	The description directly relates to the changeset, providing a clear summary of moves, updates, and test plan verification.
Linked Issues check	✅ Passed	All core requirements from issue #872 are met: base system crates moved to base/, test binaries moved to tests/userspace/, all path references updated, and all verification tests passed.
Out of Scope Changes check	✅ Passed	All changes are directly related to the reorganization objective. Minor additional fixes (rustfmt, ext2 hash, stale doc paths) support the main reorganization work.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch m872-reorg-userspace

---

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@Cargo.toml`:
- Around line 19-28: Docs still reference old userspace/... locations; update
those references to the new workspace layout by finding and replacing
occurrences of the legacy "userspace/" paths in documentation (e.g., inspect
dst-478-investigation.md and fork-loop.md for lines mentioning userspace/) with
the appropriate new targets such as "base/..." or "tests/userspace/..." (match
each reference to the corresponding new package like "base/init",
"base/vibix_abi", "tests/userspace/hello", etc.) and verify links render
correctly.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 4b76c9c5-23bc-47f6-96a2-0e9444f6015b

📥 Commits

Reviewing files that changed from the base of the PR and between 8385dca and 6bbab72.

📒 Files selected for processing (52)

• .github/workflows/smoke-soak.yml
• Cargo.toml
• base/init/Cargo.toml
• base/init/link.ld
• base/init/src/main.rs
• base/ld_vibix/Cargo.toml
• base/ld_vibix/link.ld
• base/ld_vibix/src/elf.rs
• base/ld_vibix/src/main.rs
• base/ld_vibix/src/reloc.rs
• base/ld_vibix/src/serial.rs
• base/lib/ld-musl-x86_64.so.1
• base/vibix_abi/Cargo.toml
• base/vibix_abi/src/alloc.rs
• base/vibix_abi/src/errno.rs
• base/vibix_abi/src/fs.rs
• base/vibix_abi/src/futex.rs
• base/vibix_abi/src/lib.rs
• base/vibix_abi/src/process.rs
• base/vibix_abi/src/stdio.rs
• base/vibix_abi/src/syscall.rs
• base/vibix_abi/src/thread.rs
• base/vibix_libc/Cargo.toml
• base/vibix_libc/src/errno.rs
• base/vibix_libc/src/fcntl.rs
• base/vibix_libc/src/helpers.rs
• base/vibix_libc/src/lib.rs
• base/vibix_libc/src/stat.rs
• base/vibix_libc/src/unistd.rs
• base/vibix_libc_defs/Cargo.toml
• base/vibix_libc_defs/src/lib.rs
• docs/RFC/0009-std-on-vibix.md
• library/std/Cargo.toml
• tests/fixtures/ext2_image.sha256
• tests/userspace/hello/Cargo.toml
• tests/userspace/hello/link.ld
• tests/userspace/hello/src/main.rs
• tests/userspace/hello_dyn/Cargo.toml
• tests/userspace/hello_dyn/link.ld
• tests/userspace/hello_dyn/src/main.rs
• tests/userspace/pjdfstest_runner/Cargo.toml
• tests/userspace/pjdfstest_runner/link.ld
• tests/userspace/pjdfstest_runner/src/main.rs
• tests/userspace/repro_fork/Cargo.toml
• tests/userspace/repro_fork/link.ld
• tests/userspace/repro_fork/src/main.rs
• tests/userspace/shell_pipeline/Cargo.toml
• tests/userspace/shell_pipeline/link.ld
• tests/userspace/shell_pipeline/src/main.rs
• tests/userspace/std_hello/Cargo.toml
• tests/userspace/std_hello/src/main.rs
• xtask/src/main.rs