Commit Graph
7 Commits
Author SHA1 Message Date
Robert Allan JamesandClaude Sonnet 5 36d832ff47 Single-block relocation: RELOCATE-BLOCK, resolve_lbn(), persisted exception table
Implements the full design from the prior commit in one pass. resolve_lbn()
is the single choke point threaded through the ten public LBN-consuming
entry points (blk_get_buffer, blk_update, blk_flush, blk_is_allocated,
blk_mark_allocated, blk_mark_free, blk_is_valid, blk_get_meta, blk_set_meta,
plus blk_get_empty_buffer covered via delegation) -- an LBN->LBN redirect,
not a new storage allocator, since the LBN space is already unified across
every attached blkio_dev backend. VM window cache staleness across a
relocation reuses the existing blk_vm_check_epoch() mechanism from
Milestone 2h's hot-detach fix for free -- g.epoch bumps on relocation too.

Persistence lands in the same pass: two new uint32_t fields
(reloc_start/reloc_devblocks) appended after hdr_crc in blk_volume_meta_t,
carved from existing padding without moving any earlier field's byte
offset -- an old formatted volume's zeroed padding reads back as
reloc_devblocks=0 ("no reloc capacity"), gracefully, not a format-breaking
change. compute_totals_from_B() generalized to account for the new
reserved region. reloc_flush_to_disk()/reloc_load_from_disk() mirror the
BAM I/O functions' own absolute-devblock-addressing shape; the persisted
copy's owner is first_disk_slot() (already existed, already used for this
exact "which device is canonical" question by blk_get_volume_meta()).
blk_subsys_relocate_block() is a mechanical primitive only -- copies
content (staged through a local buffer, since obtaining the target's
blk_get_buffer() result can evict and invalidate the source's cache
pointer if they share a device), frees the source BAM entry, appends the
exception entry, bumps the epoch, flushes to disk. RELOCATE-BLOCK exposes
it to FORTH, no policy of its own (ACL's job, per this session's direction).

A first live-test attempt gave a false negative against disk/artemis.img
(predates reloc capacity, so relocation only ever existed in memory that
boot) -- traced to the test's own setup before being mistaken for a bug,
then re-verified correctly against a fresh volume (new fixture,
disk/artemis-reloc-test.img): relocated a RAMDRIVE block to the fresh
disk, confirmed live resolution through the redirect, then confirmed both
the redirect and the relocated content survived an abrupt QEMU kill and
full reboot. Also fixed three lingering "glibc" doc-comment
misattributions from Milestone 2h (the actual allocator is this kernel's
own kmalloc) that survived an earlier FABRIC-2.md-only correction. All
three architectures re-verified clean.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CXjAPTEKrgY2Mrk25KoLDn
2026-08-25 19:14:01 -04:00
Robert Allan JamesandClaude Sonnet 5 8eaefeb9ee sk_repl_idle() auto-flush: implement Section V's "anything dirty? no? done" check
Makes blk_vm_flush_all() (block_words.c) non-static and declares it in
block_words.h -- it's already the entire implementation behind
SAVE-BUFFERS (block_word_save_buffers() is a one-line wrapper), so
sk_repl_idle() can call the exact same flush path outside word dispatch
without duplicating any logic. Cheap every idle tick regardless of dirty
state: every check inside is a small fixed-size scan, so no separate
pre-check was needed on top of it.

Caught a real bug via a live persistence test before trusting the
feature: the first version gated the flush on sk_repl_get_active_vm()
returning non-NULL, but NULL is that accessor's documented default
(Tripod's own USE-redirect override, "restore default dispatch") --
without an active USE redirect, the flush silently no-op'd for the
entire session. Confirmed live: wrote a byte via BUFFER (no
UPDATE/SAVE-BUFFERS), waited past the idle cadence, killed QEMU abruptly,
rebooted with the same disk image, read back 0 instead of the written
65. Fixed by threading the VM sk_repl_run()'s own loop already resolves
each iteration (g_repl_active_vm ? g_repl_active_vm : vm) down as a
parameter through sk_readline() into sk_repl_idle(), rather than trying
to re-derive it from an accessor with the wrong default. Re-ran the same
test after the fix: read back 65, matching the written byte -- the write
survived an abrupt kill with no explicit flush call anywhere in the
test, proving the idle-tick auto-flush genuinely ran.

All three architectures re-verified clean. FABRIC-2.md Section V item 6
and the corresponding Milestone 3 punch-list item marked done.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CXjAPTEKrgY2Mrk25KoLDn
2026-08-25 14:51:02 -04:00
Robert Allan JamesandClaude Sonnet 5 af267a52a6 Artemis Milestone 2h: hot-detach -- 2h complete
blk_subsys_detach_device() (block_subsystem.c) walks the device chain,
refuses removal of anything but the current tail (a mid-chain removal
would corrupt every later slot's start_lbn -- this architecture's own doc
already argues USB stays last specifically to avoid that), unlinks,
shrinks total_user_lbn, closes and frees the slot. Discards rather than
flushes dirty state -- the device is physically gone by the time this
runs (PORTSC disconnect only). Trigger wiring mirrors the attach path:
bot_msc_attached (set only once attach actually succeeds) gates a new
bot_msc_detach_pending flag set at PORTSC disconnect (not Disable Slot
completion, which is conditionally skipped and would miss concurrent
connect/disconnect pairs), consumed in sk_repl_idle().

Advisor flagged the real hazard ahead of time: block_words.c's VM block
window (blk_vm_lbn[]/blk_vm_cbuf[]) can go stale across a detach then a
same-LBN re-attach, and suggested a pointer-identity re-check in
blk_vm_load() as a minimal fix. That fix was implemented, then directly
falsified by its own designed-for-this test: attach a blank device, read
a block (populating the cache), detach, re-attach a device with distinct
content at the identical LBN, read again -- served stale content from
the first device. Root cause, confirmed live: glibc's allocator hands
free(slot) straight back to the very next same-size calloc(), so the
"fresh" and stale pointers were bitwise identical despite being two
different devices. Fixed properly with a monotonic blk_subsys_epoch()
counter (bumped on every attach/detach) checked by a new
blk_vm_check_epoch() helper at the one choke point (blk_vm_find(), plus
blk_vm_flush_all() which reads the same arrays directly) that covers
every path touching the window cache -- unfooled by address reuse.

Verified live with a new disk/usb-thumbdrive-test2.img fixture (distinct
content from the existing blank test image): attach A, read (cache hit
populated), detach, re-attach B at the same LBN, read again -- correctly
ran a fresh device read and returned B's real content, not A's stale
cached zeros. The failing pointer-comparison attempt's own capture log
kept as evidence, not deleted. All three architectures re-verified clean.
FABRIC-2.md Section X 2h marked complete -- enumeration through
hot-detach all live and verified; only WRITE(10) (2g's own still-open
item) remains unimplemented in the driver, not blocking anything here.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CXjAPTEKrgY2Mrk25KoLDn
2026-08-25 14:10:05 -04:00
Robert Allan James 1cb68502fb Add Artemis stress test for detecting cache aliasing bugs. Include statistical hypothesis evaluations, fix validation data, and run reports for validation across architectures.
Signed-off-by: Robert Allan James <robert.allan.james@gmail.com>
2026-08-02 14:49:52 -04:00
Robert Allan JamesandClaude Sonnet 5 148c4aa12c Fix silent disk overwrite of unrecognized Artemis disks
The generic block subsystem (blk_format_or_load_disk) auto-reformatted
any disk lacking its own low-level 'STFR' header at attach time, before
Artemis's Forth-level BLANK/LithosAnanke/Unrecognized classification
ever ran -- so ART-HALT-UNRECOG's "Disk preserved" message was false.

Split detection from commit: an unrecognized/blank disk is now left
PROVISIONAL (geometry computed in memory only, all writes refused)
until explicitly confirmed via the new blk_subsys_confirm_format() /
BLK-CONFIRM-FORMAT primitive. Artemis calls it from ART-FORMAT and
ART-RESUME, never from ART-HALT-UNRECOG.

Verified on amd64/aarch64/riscv64: parity intact (identical dict_hash),
normal recognized-disk resume + persist-read unaffected, and a
regenerated disk/artemis-unrecognized-test.img (the old copy had itself
been silently corrupted by this exact bug) now stays byte-for-byte
identical across a halted boot on amd64 and riscv64.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
2026-08-02 11:44:23 -04:00
Robert Allan JamesandClaude Sonnet 5 cc6c8c43f3 Fix ABORT to actually unwind to QUIT instead of one level
ABORT is documented and tested in this codebase as standard FORTH-79
behavior -- system_words_test.c:63: "Should clear stacks and return to
QUIT" -- meaning it should unwind all the way back to the outermost
interpreter loop, abandoning whatever's left of the current line/block.
The implementation only unwound one level: every place that checked
vm->abort_requested cleared it the instant it saw it, so it never
survived to propagate past the first nested frame.

This surfaced via Artemis's ART-HALT-UNRECOG (capsules/artemis/init.4th):
on an unrecognized disk it correctly printed "ARTEMIS HALT: unrecognized
disk content" and called ABORT, but WELCOME (the next line in the same
block) ran anyway, and Artemis announced ready to Hermes and joined the
fleet normally -- contradicting .claude/ARTEMIS.md's "Refuse to mount...
do not overwrite it" requirement. Root cause is general, not
Artemis-specific, and present identically in both the hosted and kernel
VM cores.

Fixed at every level execution can nest through, verified by exhaustively
grepping every !vm->error-gated continuation loop and adding the parallel
!vm->abort_requested check:

- execute_colon_word (src/vm.c, src/starkernel/vm/vm_core.c): stop
  clearing the flag on return -- every colon-word call is a recursive
  call to this same function, so leaving it set lets every enclosing
  frame's own check also unwind.
- vm_interpret (src/vm.c, src/starkernel/vm/vm_core.c): stop parsing
  further words in the current input string once the flag is set.
- exec_block_with_retry (src/starkernel/capsule/capsule_loader.c):
  capsule birth's line-by-line block executor -- stop processing further
  lines in the current block, but return 0 (not -1), so
  capsule_exec_payload still loads later blocks in the same capsule
  payload. Returning -1 here would have silently broken word definitions
  in blocks that come after the aborting one for reasons unrelated to
  why it aborted (concretely, Artemis's ART-PING/LOAD-DOE in blocks
  4851/4852, which follow the entry block 4133).
- THRU and --> (src/word_source/block_words.c): stop processing further
  blocks/lines in their own loops.
- DODOES (src/word_source/defining_words.c): the CREATE...DOES> runtime
  has its own hand-rolled execution loop, separate from
  execute_colon_word -- same bug class, same fix. Also guarded the
  post-loop "if (vm->rsp < base_rsp) vm->rsp = base_rsp" clamp so it
  doesn't fire on an abort exit -- ABORT's own reset_vm_state() already
  set rsp; restoring it to base_rsp would have partially undone that.
- Both REPL loops (src/repl.c, src/starkernel/repl.c x2 call sites):
  clear the flag after each line, mirroring the existing vm->error
  pattern, so a mid-line abort doesn't silently freeze subsequent
  interactive input.

Verified directly: ": AB-TEST 1 2 3 ABORT 999 . ;  AB-TEST 42 . CR
777 . CR" -- 999 never prints (stops mid-colon-word), 42 never prints
(stops the rest of the same line), 777 prints fine (next line
unaffected). Artemis: WELCOME/"Artemis ready" no longer fires after the
halt message. No regression: all three architectures still show PASS:
persist-read, PASS: E2E msg flow, and matching dict_hash on the normal
(non-aborted) boot path; hosted test suite 965 passed / 0 failed.

Known follow-up, not fixed here (see memory for details): Artemis still
announces ready to Hermes via a separate call path (CD-INIT, block 4141)
that never went through capsule_exec_payload's block chain in the first
place, and the disk file still picks up incidental writes even on a
correctly-halted boot -- likely generic block-subsystem housekeeping,
not traced yet.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
2026-08-02 10:07:18 -04:00
Robert Allan James a5ed8c3d87 Initial commit — LithosAnanke kernel 2026-08-01 07:49:56 -04:00