Robert Allan JamesandClaude Sonnet 5
736627510b
kernel_main on riscv64 ran directly on EDK2's UEFI boot-time stack, with no dedicated stack switch — amd64 has always had a kernel_entry.S trampoline for exactly this reason (its own comment: "the FORTH interpreter + DOE experiment loop can easily exceed that depth"). aarch64 happens to get away without one because its firmware's default stack is apparently larger, but that was never a guarantee. On riscv64 the VM bootstrap's call depth (27 word-registration modules -> physics/SSM init -> Tripod capsule birth) overflowed that small stack, corrupting a return address and producing a wild jump / page fault right after vm_init_with_host() returned — reproduced consistently across the 2026-08-01 DoE campaign logs. - src/starkernel/arch/riscv64/kernel_entry.S (new): RISC-V stack-switch trampoline mirroring amd64's, giving the kernel a dedicated 2 MiB BSS stack before anything deep runs. - kernel_main.c: riscv64 now builds kernel_main_impl (invoked via the trampoline) instead of kernel_main directly, same pattern as amd64. - Makefile.starkernel: wires the new file into the riscv64 build. - uefi_loader.c: RAW_LOG() was silently a no-op on every non-amd64 arch; added a real raw-UART writer for riscv64 (QEMU virt's uart8250 at MMIO 0x10000000) so existing loader diagnostics actually produce output. Verified: all three architectures boot clean to [Hera] ok> in the required order (amd64, aarch64, riscv64); logs and DoE CSVs from these runs included. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
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.