Robert Allan JamesandClaude Sonnet 5
57ac3fc304
Second stage of the preemptive context-switching plan. Every VM (Hera, every capsule_birth_baby()-born VM including WIREBIND identities) now gets its own dedicated 2 MiB native C stack at birth -- but nothing runs on it yet, that's Stage 2. Pure allocation-machinery proof. Design correction made before writing code: the plan called for cloning sk_vm_arena_alloc()'s guard-page pattern, but that pattern turns out to be Mama-only -- host_services.c's kernel_alloc() gives every baby VM a plain kmalloc() block for its dictionary arena, not a real guarded PMM allocation. Stacks get the real treatment instead (new sk_vm_native_stack_alloc()/_free() in arena.c): independent pmm_alloc_contiguous() + guard pages for every VM without exception, no singleton, no kmalloc fallback -- a stack overflow is exactly the failure mode guard pages exist for, and a corrupted stack could corrupt whatever saved context Stage 2 trusts. 2 MiB size matches this project's own established kernel-stack convention (g_kernel_stack/g_rpi5_native_stack), not a guess -- that one shared 2 MiB stack today already carries all VMs' combined nested VM-EXEC recursion. Three new VM struct fields, freed in vm_cleanup() alongside the existing call_stack free. Allocation failure is non-fatal to birth. All 3 architectures re-verified clean boot to ok>, no native-stack allocation failures for any Tripod-fleet VM. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_016UNhH1mhi52i6Qihh7ZV5S
src/starkernel/vm/
Kernel-side StarForth VM subsystem.
vm_core.c— kernel port of the core interpreter loop.vm_runtime.c— kernel VM runtime support.vm_bootstrap.c— kernel VM bootstrap (distinct frombootstrap/sk_vm_bootstrap.c, which owns the higher-level subsystem wiring called fromkernel_main.c).arena.c— capsule arena allocator (fixed-region allocation for capsule payload data).parity.c— birth/execution parity logging (VM ID + capsule hash + dictionary hash), enabling offline determinism verification.alloc_kernel.c— the kernel-side implementation of the VM's allocator interface actually referenced byMakefile.starkernel's build (seesrc/platform/README.mdfor a note on a second, unwired copy).q48_stubs.c— deliberate no-op stubs forq48_from_double()/q48_to_double()in the freestanding kernel build, where floating point is unavailable; always returns zero, safe because shared VM code only uses these results for logging/diagnostic paths that are inactive in the kernel build.vm_internal.h— internal-only declarations shared across this directory's files.
Subdirectories:
bootstrap/sk_vm_bootstrap.c— owns VM init + capsule loading wiring, called fromkernel_main.c;kernel_main.citself only owns hardware milestones.host/shim.c— host-service shim bridging the kernel VM tosrc/starkernel/hal/host_services.c.