Robert Allan JamesandClaude Sonnet 5
f790d0995e
Third stage of the preemptive context-switching plan. The real save/restore switch mechanism now exists -- the first time anything has ever executed on a VM's own native stack (Stage 1 allocated them, unused). New sk_vm_switch_to() (switch.S, one per arch) is an ordinary function call, not an interrupt -- so unlike Stage 0's trap frame, the ABI already covers every caller-saved register; only the callee-saved set needs explicit save/restore (amd64: rbx/rbp/r12-r15, no FP at all since SysV has no callee-saved XMM; aarch64: x19-x28/x29/x30 + d8-d15; riscv64: s0-s11/ra + fs0-fs11, FS-gated like Stage 0 but read once and reused for both halves within one call, since FS is genuine global CPU state, not part of what's switched). A sibling sk_vm_switch_prime() in the same file builds the synthetic first-entry frame, kept in assembly so the layout can never drift out of sync with sk_vm_switch_to() itself. New switch.c/switch.h: sk_vm_context_switch(from, to) handles first-entry priming vs. resuming a parked context, and updates registry state (new VM_STATE_SWITCHED_OUT, distinct from VM_STATE_STOPPED -- STOPPED means no live frame, this means the opposite). sk_vm_switch_entry() is the minimal permanent trampoline every freshly-entered VM lands in: no production behavior defined yet, so it just yields straight back to whoever switched to it, forever. Closes the confirmed unguarded-KILL UAF found during planning: capsule_vm_kill(), mama_word_kill(), and capsule_vm_kill_all_nonmama() all now refuse (or silently leak rather than free, on the cold-restart path where arch_cold_reset() wipes everything immediately after anyway) tearing down a switched-out VM. Side effect found, not built on purpose: the existing MSG-TICK idle-pump already filters on VM_STATE_LIVE, so it automatically stopped dispatching into a switched-out VM with zero changes needed there. Verified via a temporary SWITCH-TEST probe (boot-triggered, since nothing can type interactively into a foreground-only QEMU session) that round-tripped a sentinel through 5 real Hera<->Hermes switches on all 3 architectures: 5/5 rounds, 0 failures, clean continuation to ok>. Probe fully reverted after capture; kernel_main.c shows zero diff. Also: Makefile.starkernel's LOADER_EXTRA_SRCS/LOADER_ASM needed the new files added explicitly (this project's "loader" PE binary is the full running kernel, not a thin bootstrap stage), and aarch64's switch.S needed the same #ifndef _WIN32 guard around .hidden that isr.S already carries (aarch64's loader assembles via clang targeting a PE/COFF target with no .hidden equivalent) -- caught by a build failure, fixed. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_016UNhH1mhi52i6Qihh7ZV5S
LithosAnanke v2.0.1
UEFI-bootable FORTH microkernel. Boots from firmware, initialises memory and interrupts, then runs the StarForth VM as its sole userspace runtime. No libc. No OS. Just stone and necessity.
Lithos (foundation) + Ananke (necessity) — the kernel under StarshipOS.
Status — M7.1 (Capsule System · Multi-VM Fleet)
| Milestone | Status | |
|---|---|---|
| M0–M6 | UEFI boot · PMM · VMM · IDT · APIC · heap · framebuffer VT100 console (v1.5.1-FINAL) | ✅ Complete |
| M7 | StarForth VM integration + parity validation | ✅ Complete |
| M7.1 | Capsule birth protocol · Mama FORTH vocabulary · Tripod multi-VM fleet (Hermes/Artemis) · Word-level ACL (Phases 1–7) | 🔄 In Progress |
| M8 | REPL — keyboard input, interactive Forth | Planned |
| M9 | Block storage — AHCI driver | Planned |
POST at boot: parity hash verified across amd64/aarch64/riscv64 · Mama capsule dictionary: 453 words
What's live in M7.1
- Tripod — a named multi-VM fleet (Hera the Mama VM, Artemis, two Hermes instances) births, runs, and re-births independently, verified booting live pre-REPL on all three architectures.
- Hermes — a 17-block inter-VM messaging/channel layer between fleet members, with async delivery and channel negotiation.
- Artemis — a Block Allocation Map (BAM) storage subsystem with Q48.16
block-heat tracking and cooldown/reclamation (
ART-COOL/ART-REAP). - Word-level ACL — every dictionary entry carries a TTL/allow/mode/pin
access-control record. Strict, TTL, and pinned modes; two console layers
(emergency
ok>and superuserzuse)ok>). Phases 1–7 complete (C infrastructure, FORTH policy layer,zusebootstrap superuser, Isabelle proof stubs, kernel parity); Phase 8 (Ed25519 PKI / thumbdrive challenge-response) is the only item remaining. Measured overhead once active on every check: +0.0054%–+0.0088%, CV = 0.000%, across a 3×3 Latin-square DoE campaign (architecture × seed × 30 replicates) — three orders of magnitude below the measurement floor. - VM Fleet Attractor physics — the L8 Jacquard mode selector now has a real per-VM heat channel into fleet-wide tuning, replacing hardcoded compudynamics constants with a dynamically-inferred rate.
- Kconfig build configuration — every physics/heartbeat/pipelining/ kernel-only tuning knob (~40 total) is now a discoverable, optional Kconfig symbol shared with the hosted VM build. See Quick Start below.
Quick Start
# Build kernel (requires cross-compilation toolchain, or native gcc)
make -f Makefile.starkernel ARCH=amd64
# Run in QEMU with OVMF
make -f Makefile.starkernel qemu
# Other architectures
make -f Makefile.starkernel ARCH=aarch64 qemu
make -f Makefile.starkernel ARCH=riscv64 qemu
Artifacts: build/amd64/kernel/starkernel_loader.efi · build/amd64/kernel/starkernel_kernel.elf
For the hosted VM by itself (Linux, no cross-compiler needed, no bare-metal tooling): see
the separate StarForth repository — LithosAnanke used to be a branch inside that repo,
now it's its own project with its own master.
Build configuration (optional)
Every kernel-only knob (STARFORTH_ENABLE_VM, PARITY_MODE, the shared
physics/heartbeat family, etc.) is an optional Kconfig symbol — a plain
make -f Makefile.starkernel uses the same defaults it always has unless
you opt in:
make -f Makefile.starkernel ARCH=amd64 menuconfig
make -f Makefile.starkernel ARCH=amd64 kernel_amd64_defconfig
Documentation
| System Architecture | Full kernel + VM design |
| HAL Reference | Hardware abstraction layer interfaces |
| Capsule System — M7.1 | Capsule birth protocol design |
| VM Fleet Attractor design log | Tripod/Hermes/Artemis physics + build-system history |
| Getting Started / Kconfig reference | Full symbol reference for both build targets |
| Changelog | Milestone-level history |
| Roadmap | Milestone plan through self-hosting |
License
Starship License 1.0 (SL-1.0) — free for personal, research, and educational use. Commercial use requires a separate agreement. Attribution to R.A. James (Captain Bob) must be preserved in all distributions.
Patent pending. USPTO provisional filed December 2025 — physics-grounded self-adaptive runtime system. This license does not grant patent rights. Licensing inquiries: rajames440@gmail.com
Robert A. James (Captain Bob) · Systems Engineer · Hacking since 1973