review: fix review findings (correctness, hardening, doc-accuracy)

First recursive code-review-harness pass over the authored SDK code (sim/,
config-lint, flowgen, drivers/{relays,freshness}, build/, ci.yml). Four parallel
dimension reviewers; all findings at every severity corrected per workspace rule.

Correctness / reliability:
- freshness.c min_budget_ms: use a `seen` flag, not `best==0`, as the empty
  sentinel — a zero-tolerance (max_stale_ms==0) binding was silently widened to a
  looser neighbour's budget. Regression test added; still 66/66 MC/DC.
- config-lint parse_reserved_ranges: match `reg` as a whole property token (ident
  boundary before, `=` after) so `reg-names` / a `region-*` label no longer
  mis-parses into a bogus reserved range.
- config-lint loader check: fail closed — flag any loader with a LOAD_ADDR that is
  not a known-safe boot component, instead of only known MCU names, so a future
  coprocessor ("Rtos"/"Bl32") can't slip past the 0x40000-brick gate.
- build-kernel.sh: sha256 verification is now mandatory (refuse to build if the pin
  is missing) and the mktemp scratch tree is removed on exit (trap), while a
  caller-provided WORK is left intact for CI artifact upload.

Test quality:
- freshness: added the age==max_stale boundary case and a clock-wraparound
  (now < last_ok) fail-safe-to-UNKNOWN test.
- relays: unsetenv(WARDEN_GPIO_ROOT) at main() so the NULL-env arm is hermetic.

Security / CI:
- ci.yml: top-level `permissions: contents: read` (badges overrides to write);
  pin taiki-e/install-action to commit SHA (v2.86.7).

Maintainability / docs:
- drivers/enforce-mcdc.sh: one shared, name-derived gate replaces the two
  copy-pasted per-driver scripts; Makefiles call ../../enforce-mcdc.sh.
- docs/architecture.md: §3/§4/§6/§7 rewritten to match reality — NPU/RGA models,
  config-lint, and the relays+freshness MC/DC harnesses are done; kernel §6 now
  reflects the 5.10->6.18.46 forward-port (ADR-0001), not the superseded plan44/6.6.
- README: status blurb + layout table corrected (kernel/, .github/; stale ci/ and
  patches/ descriptions fixed). hpmcu "8 tests" -> 7 in docs.
- freshness.{c,h}: ADR reference points at flare-edge ADR-0004 (warden-sdk's
  ADR-0004 is the CI runner — number collision).
- normalize rustfmt drift across sim/ + config-lint.

All green: sim 37 tests, config-lint 8 tests, both drivers 100% MC/DC (relays
40/40, freshness 66/66), clippy clean under -D warnings, gitleaks clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017wB8KB3MMQztRDXCMCkPrf

drivers/freshness/freshness.c

@@ -1,5 +1,5 @@
 /*
- * The UI Freshness Contract engine (ADR 0004) — core, LVGL-free.
+ * The UI Freshness Contract engine (flare-edge ADR-0004) — core, LVGL-free.
  * See freshness.h for the contract. LVGL binding lives in freshness_lv.c.
  */
 #include "freshness.h"
@@ -175,11 +175,16 @@ uint32_t warden_fresh_count(void)
 
 uint32_t warden_fresh_min_budget_ms(void)
 {
+    /* `seen` — not `best == 0` — marks "nothing scanned yet", so a legitimate
+     * zero-tolerance binding (max_stale_ms == 0, "must be fresh every tick") wins
+     * the minimum instead of being mistaken for the empty sentinel and widened. */
     uint32_t best = 0;
+    bool seen = false;
     for(uint32_t i = 0; i < FRESH_MAX; i++) {
         struct warden_fresh *v = &s_vals[i];
-        if(v->used && v->visible && (best == 0 || v->max_stale_ms < best)) {
+        if(v->used && v->visible && (!seen || v->max_stale_ms < best)) {
             best = v->max_stale_ms;
+            seen = true;
         }
     }
     return best;

drivers/freshness/freshness.h

@@ -1,5 +1,5 @@
 /*
- * The UI Freshness Contract engine (ADR 0004) — core, LVGL-free.
+ * The UI Freshness Contract engine (flare-edge ADR-0004) — core, LVGL-free.
  *
  * The panel is read on-site to judge whether hardware is healthy, so a silently
  * *stale* number is worse than a missing one: a stale IP or hashrate reads as

drivers/freshness/test/Makefile

@@ -31,7 +31,7 @@ check: $(BUILD)/test
 	@echo "== MC/DC (condition) coverage of freshness.c =="
 	@$(GCOV) --conditions --branch-probabilities -o $(BUILD) ../freshness.c >$(BUILD)/gcov.log 2>&1 || true
 	@mv -f *.gcov $(BUILD)/ 2>/dev/null || true
-	@bash enforce-mcdc.sh $(BUILD)/gcov.log $(BUILD)/freshness.c.gcov $(BUILD)/test.rc
+	@bash ../../enforce-mcdc.sh $(BUILD)/gcov.log $(BUILD)/freshness.c.gcov $(BUILD)/test.rc
 
 report: check
 	@grep -nE "condition.*not covered|conditions covered" $(BUILD)/freshness.c.gcov || true

drivers/freshness/test/enforce-mcdc.sh

@@ -1,48 +0,0 @@
-#!/usr/bin/env bash
-# Gate: fail unless every unit check passed AND freshness.c reached 100% MC/DC
-# (condition) coverage with no uncovered executable lines.
-#   $1 = gcov stdout log   $2 = freshness.c.gcov   $3 = test exit-code file
-set -uo pipefail
-LOG="$1"; GCOV="$2"; RCFILE="$3"
-rc=0
-
-testrc="$(cat "$RCFILE" 2>/dev/null || echo 1)"
-if [ "$testrc" != "0" ]; then
-	echo "RESULT: unit checks FAILED (test exit $testrc)"; rc=1
-else
-	echo "RESULT: all unit checks passed"
-fi
-
-if [ ! -f "$GCOV" ]; then
-	echo "RESULT: no coverage file ($GCOV) produced"; exit 1
-fi
-
-notcov="$(grep -nE "condition[s]? .*not covered" "$GCOV" || true)"
-uncov_lines="$(grep -nE "^ +#####:" "$GCOV" || true)"
-
-# Summary lines for freshness.c from gcov stdout. Match the exact file so
-# 'test_freshness.c' (which also contains "freshness.c") is NOT picked up.
-FMATCH="File '([^']*/)?freshness[.]c'"
-cond_line="$(awk -v patt="$FMATCH" '$0 ~ patt {f=1} f&&/Condition outcomes covered:/{print; f=0}' "$LOG")"
-line_line="$(awk -v patt="$FMATCH" '$0 ~ patt {f=1} f&&/Lines executed:/{print; f=0}' "$LOG")"
-echo "  ${line_line:-Lines executed: (n/a)}"
-echo "  ${cond_line:-Condition outcomes covered: (n/a)}"
-
-if [ -n "$notcov" ]; then
-	echo "RESULT: MC/DC gaps (conditions not covered):"
-	echo "$notcov" | sed 's/^/    /'
-	rc=1
-fi
-if [ -n "$uncov_lines" ]; then
-	echo "RESULT: uncovered executable lines in freshness.c:"
-	echo "$uncov_lines" | sed 's/^/    /'
-	rc=1
-fi
-
-if ! echo "$cond_line" | grep -q "100.00%"; then
-	echo "RESULT: condition coverage is below 100%"
-	rc=1
-fi
-
-[ "$rc" = "0" ] && echo "RESULT: 100% MC/DC + all checks green ✓"
-exit "$rc"

drivers/freshness/test/test_freshness.c

@@ -44,6 +44,9 @@ static void test_decide(void) {
     EXPECT(warden_fresh_decide(FRESH_UNKNOWN, false, false, 0,   100) == FRESH_RENDER_UNKNOWN);
     EXPECT(warden_fresh_decide(FRESH_UNKNOWN, true,  false, 200, 100) == FRESH_RENDER_UNKNOWN);
     EXPECT(warden_fresh_decide(FRESH_UNKNOWN, true,  false, 50,  100) == FRESH_RENDER_NOCHANGE);
+    /* boundary: age == max_stale is NOT stale (guards a `>`->`>=` regression that
+     * MC/DC alone would not catch — both outcomes are already covered above). */
+    EXPECT(warden_fresh_decide(FRESH_UNKNOWN, true,  false, 100, 100) == FRESH_RENDER_NOCHANGE);
 }
 
 /* --- 2. bind: !produce, !render, valid, and table-full (FRESH_MAX=2) --- */
@@ -121,10 +124,18 @@ static void test_invalidate(void) {
     EXPECT(g_render_calls == 1);
 }
 
-/* --- 6. min_budget: best==0 first, then max_stale<best true and false --- */
+/* --- 6. min_budget: unseen first, then max_stale<best true and false --- */
 static void test_min_budget(void) {
     warden_fresh_reset();
     EXPECT(warden_fresh_min_budget_ms() == 0);     /* nothing bound */
+    /* regression (correctness review): a zero-tolerance binding (max_stale=0) must
+     * win the minimum, not be mistaken for the "nothing scanned" sentinel and
+     * widened to a looser neighbour's budget. */
+    warden_fresh_bind((void*)1, fake_produce, NULL, 0,   "s", fake_render, (void*)9);
+    warden_fresh_bind((void*)1, fake_produce, NULL, 300, "s", fake_render, (void*)9);
+    EXPECT(warden_fresh_min_budget_ms() == 0);
+    warden_fresh_reset();
+    EXPECT(warden_fresh_min_budget_ms() == 0);     /* nothing bound (post-reset) */
     warden_fresh_bind((void*)1, fake_produce, NULL, 300, "s", fake_render, (void*)9); /* best=0->300 */
     warden_fresh_bind((void*)1, fake_produce, NULL, 100, "s", fake_render, (void*)9); /* 100<300 -> 100 */
     EXPECT(warden_fresh_min_budget_ms() == 100);
@@ -160,6 +171,22 @@ static void test_false_arms(void) {
     EXPECT(g_render_calls == 0);
 }
 
+/* --- 8. clock wraparound: a uint32 ms counter wraps every ~49.7 days, so a tick
+ *        can arrive with now_ms < last_ok_ms. The unsigned `now - last_ok_ms` then
+ *        underflows to a huge age; the contract must fail SAFE to UNKNOWN, never
+ *        assert the last value as if still fresh. --- */
+static void test_wraparound(void) {
+    warden_fresh_reset();
+    warden_fresh_bind((void*)1, fake_produce, NULL, 100, "s", fake_render, (void*)9);
+    set_produce(FRESH_OK, "9"); reset_render();
+    warden_fresh_tick(1000);                       /* last_ok_ms = 1000, ever_ok */
+    EXPECT(g_render_calls == 1 && g_render_what == FRESH_RENDER_VALUE);
+    /* now wraps behind last_ok_ms: age underflows -> treated as stale -> UNKNOWN */
+    set_produce(FRESH_UNKNOWN, NULL); reset_render();
+    warden_fresh_tick(10);
+    EXPECT(g_render_calls == 1 && g_render_what == FRESH_RENDER_UNKNOWN);
+}
+
 int main(void) {
     test_decide();
     test_bind();
@@ -168,6 +195,7 @@ int main(void) {
     test_invalidate();
     test_min_budget();
     test_false_arms();
+    test_wraparound();
     fprintf(stderr, "%d checks, %d failures\n", g_checks, g_fail);
     return g_fail ? 1 : 0;
 }