Cohesix Documentation
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Root Task Crate

root-task is the initial pure-Rust seL4 task for the selected Cohesix QEMU and Pi 4 profiles. It owns bootstrap and policy, admits manifest-declared resources through HAL, launches restricted service and Worker children, and projects their bounded results into the authenticated operator surfaces. Physical steady-state device work stays in isolated driver runtimes.

The two operational feature closures are explicit and default features are empty:

  • release-qemu: four-core aarch64/virt, MCS, GICv3, exported virtual counter, PL011 emergency serial, VirtIO console networking, and the selected service/Worker images.
  • release-pi4: four-core BCM2711 MCS, selected generated timer truth, emergency serial, and manifest-declared Pi driver/service/Worker images.

dev-virt, timer bypasses, mock seL4, early exits, and diagnostic driver smokes are explicit non-production features. They cannot satisfy target, integration, release, or use-case evidence.

Production fail-closed behavior

An operational boot requires real generated timer frequency and an admitted serial backend. Userland no longer substitutes a null serial driver. The early console advertises only implemented pre-authentication diagnostics and returns a typed authorization refusal for reboot; authenticated reboot is handled only by the event pump. Target namespace state begins unavailable and empty until a validated provider snapshot arrives. The unused IPC trace alias and legacy PL011 bootstrap REPL are not selected.

Build and checks

Use the repository build runner so seL4 profile validation, child-image packaging, exact GIC selection, and system-CPIO construction stay aligned:

scripts/cohesix-build-run.sh --clean --no-run --cargo-target aarch64-unknown-none

Focused source checks:

cargo test -p root-task --test production_fallbacks
cargo test -p root-task --tests
SEL4_BUILD_DIR="$PWD/out/sel4/profile-v2/qemu-smp-production" \
  cargo check --locked --target aarch64-unknown-none \
  -p root-task --no-default-features --features release-qemu

QEMU source/build success is not Pi 4 hardware acceptance. Pi tests follow only after the M26e QEMU closure is complete and frozen.

See ARCHITECTURE.md, ROLES_AND_SCHEDULING.md, and TEST_PLAN.md for the generated topology and evidence requirements.