Before flipping, found CAPSULE_SIG_MISSING (no signature at all) is the normal state everywhere except this machine -- CI and any other checkout have no access to the offline key, by design. Refusing on MISSING the same as INVALID would brick boot everywhere but here. Decided (on request): enforce ONLY on CAPSULE_SIG_INVALID (a signature that IS present but doesn't verify -- unambiguous tampering/corruption evidence). MISSING/NO_ROOT_KEY stay WARN-only permanently. All three capsule_birth.c call sites now return CAPSULE_RUN_ERR_INVALID on CAPSULE_SIG_INVALID, after logging the same WARN as before. Verified on all three architectures, both directions, per the original rollout commitment: positive case (real signed capsules) reboots clean with zero warnings on amd64/aarch64/riscv64. Negative case (same one-byte signature corruption used for the WARN-only proof, on Mama's own init.4th) now genuinely refuses identically on all three: "capsule sig: init.4th: INVALID" then "Init: Mama birth FAILED". The feared "no ok> at all" blast radius didn't materialize -- kernel_main.c already had graceful error handling for a failed Mama birth (log and continue, pre-existing code); the kernel reaches a degraded ok> rather than crashing, on all three architectures. Final acceptance pass (real signed capsules, tampering reverted) clean on all three. Milestone 6 is now fully closed except magic-number content-type detection (shared with Milestone 4, separate scope, not started). Documented in FABRIC-3.md. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01U14ET9CWAtbQMbYqomKgXd
src/starkernel/
LithosAnanke — the bare-metal UEFI kernel that boots StarForth directly on
hardware (amd64/aarch64/riscv64). Built only via Makefile.starkernel; the
only valid acceptance test is the three-arch QEMU boot (see
.claude/CLAUDE.md), never make test.
kernel_main.c— kernel entry point, driving the boot milestones (console init, PMM, VMM, interrupts, timers, kmalloc heap, VM bootstrap).repl.c— kernel REPL.doe_log.c— kernel-side DoE (Design of Experiments) metrics logging.
Subdirectories:
arch/{amd64,aarch64,riscv64}/— per-architecture support (APIC/GIC/ PLIC interrupt controller, timers, boot/ISR assembly).boot/— UEFI loader, ELF loading, kernel command-line parsing.capsule/— capsule birth/run/load/validate pipeline.hal/— hardware-abstraction-layer implementation (console, framebuffer, VT100, memory, host services).hash/— XXHash64 content-addressing implementation.math/— kernel-build Q48.16 fixed-point arithmetic.memory/— physical/virtual memory managers and the kernel heap.pci/— PCI bus enumeration.virtio/— VirtIO block device driver.vm/— kernel VM subsystem (bootstrap, core interpreter, parity logging, capsule arena).
See include/starkernel/README.md for the corresponding headers.