Memory intervention source and native fixture proof

Evidence class: actual patch-applied C native fixtures, immutable source/API inspection and pure Nix identity evaluation. Matching full kernel/system/bundle, actual selected config/dev headers and RISC-V object/lifetime/layout remain UNVERIFIED. Positive controller preparation, physical output/receipt/recovery and task 5b.5 stay open. No full kernel build or board/UART/camera action occurred.

Worktree /home/jadams/tmp/k230-mainline-uart-progress-memory, branch mainline-uart-progress-memory, base a4d6958dddf9572320b63c96b4777c959424ece9. Owned: new Memory patch/recipe, additive flake family, native fixtures, source-host evidence and only task 5i.1. Shared build lock used only for pure identity evaluation, never derivation realization.

GNU patch --batch --fuzz=0 -p1 applied the new zero-context patch to immutable /nix/store/wnvbxaiqgbhhajsajy5mlpn36zf8alga-linux-mainline-k230-uart-progress-post-sample-src/drivers/soc/canaan/k230-uart-progress.c. Parent worker SHA-256: aee68aaec5c5c0e2b23919901eb99189265fd2b4787a0e50bc11159afd81ef9b. Applied Memory worker SHA-256: 307d7c0588499dd32826c1d05476e0bf6d46ca0c8939d42e0b4f7180545b98dc. Portable native fixtures reconstruct the same parent from existing repository patches, then apply only the new Memory layer. Existing patches/recipes, getter/timer sources, configuration and artifact parameters are untouched.

Only exact k230.uart_progress_memory=1, base progress opt-in, CONFIG_RISCV_SBI and actual DBCN availability enable the intervention. It suppresses every worker output, including numeric and both earlier point families, while retaining six 5000ms sleeps, cached snapshots, stop checks, normal priority and termination. The typed controller rejects simultaneous Breadcrumbs/PostSample selectors; the source suppresses their worker writes even if those flags are present. Absent/bare/invalid Memory gate retains inherited behavior and creates no observer. No IRQ/PID1/TTY/MMIO/clock/console-policy or scheduler-policy change is added. The added normal-priority observer changes the workload/timing; this remains an intervention rather than a passive observation of identical execution.

A separate ordinary atomic state packs stage bits[2:0], current index[5:3] and completed-snapshot bitmap[11:6]. Each publication is one atomic_set_release; observer uses ONE atomic_read_acquire, with no retry/seqcount loop. The last completed index is derived from that single bitmap in a six-iteration bounded loop. State/helpers/flags/completion/buffer have ordinary lifetimes; setup alone uses init lifetime. The new public summary format, with lowercase two-digit hex:

\nK230_UMP1 s=%u n=%u m=%02x l=%u w=%u\n

Allowed masks are 00/01/03/07/0f/1f/3f. l is the highest completed index or6 when mask00. w1 means completion wait returned nonzero and requires terminal stage4/5/6; w0 means timeout returned zero and may contain a terminal stage if publication races timeout. Receipt and recovery are separate facts.

The observer is created before the worker, waits once with wait_for_completion_timeout(..., msecs_to_jiffies(45000)), then copies state and attempts ONE final bounded-size DBCN write. Its ordinary 256-byte buffer has 256-byte alignment; length must be positive and less than sizeof(buffer). Observer creation failure returns the known init error without starting a worker/output. Worker creation failure publishes stage6 then completes the wait. Worker termination publishes its terminal state before completion. The selected source declares the atomic acquire/release API in include/linux/atomic/atomic-instrumented.h and completion/wait API in include/linux/completion.h; exact matching target object proof remains open.

python3 tests/test_mainline_uart_progress_memory.py
python3 tests/test_mainline_uart_progress_post_sample.py
python3 tests/test_mainline_uart_progress_breadcrumbs.py
python3 tests/test_mainline_uart_progress.py

Thirteen new fixtures passed (0.420s), plus prior 15/13/12 fixtures (0.318s/0.201s/0.068s). New tests compile actual patch-applied C with GCC -std=gnu11 -Wall -Wextra -Werror and isolated callbacks. They execute gates, all twelve stop boundaries, creation failures, completion/timeout/terminal races, exact coherent publication values and one acquire read, unchanged absent-mode bytes/events and one full/partial/zero/error output attempt. Callback timing/atomics/completion are isolated native models, not actual concurrent Linux scheduling, kernel memory-ordering or firmware progress proof. CONFIG-off is an isolated fixture, not a valid selected board kernel. Callback argument capture does not establish delivered UART bytes. Parent-only unused new fixture stubs are exempted from unused-function warnings.

flock -n /tmp/k230-nix-build.lock nix eval --offline --no-write-lock-file \
  --json --impure --expr \
  'import /home/jadams/tmp/k230-mainline-uart-progress-memory/docs/evidence/mainline-uart-progress-memory/source-host/check-identities.nix { root = /home/jadams/tmp/k230-mainline-uart-progress-memory; }'
nix eval --offline --no-write-lock-file --raw \
  .#packages.x86_64-linux.toplevel-mainline-uart-progress-memory.drvPath
nix derivation show /nix/store/h485sr26ipaabfmn29x5qj38qxxzp3x1-linux-mainline-k230-uart-progress-memory-src.drv
nix-instantiate --parse nix/kernel-mainline-uart-progress-memory.nix
nix-instantiate --parse flake.nix
openspec validate the-board-runs-a-mainline-kernel --strict
openspec validate --all
git diff --check

Pure identity evaluation passed all 99 pre-existing package drv identities and 12 exposed kernel source/config pairs, inherited structured config/parameters and selected kernel assertion against the full declared base. The source derivation layers exactly over immutable PostSample source with only the new Memory patch. Receipt records these evaluated selections, not realized matching artifacts. An initial evaluation rejected an abbreviated Git base hash before evaluating any identity. The successful expression initially printed its parent system in an output-only field; that field now uses the selected config toplevel and the Memory system was separately evaluated. Parse/strict/all validation (56 passed) and whitespace checks pass. Both cached start/handoff scans completed0, and the pure-evaluation lock is released. Actual matching full/build-object/controller/hardware tasks remain open.

This is an intervention removing repeated firmware TX from the measured worker. A received summary proves recorded progress BEFORE its final output call; it does not prove that call returned or diagnose firmware/IRQ/RX/root. Finite kernel wait is not an absolute boot or firmware wall-clock deadline. Missing summary leaves worker, observer, timer/scheduler and output unknown; an M-mode stall can prevent the S-mode observer from executing. Root owns matching build, positive preparation, physical use and fresh normal recovery.