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starkernel: TimeTrustState.ticks -- mark volatile, fixing the one hazard 4.5a found

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Written directly in ISR context on all three architectures
(heartbeat_tick(), heartbeat.c:163) and read directly by mainline
(heartbeat_ticks(), including the busy-wait at kernel_main.c:880) without
being volatile -- worked by accident at -O0, would be a real bug once the
kernel builds with optimization (item 4.5). Every other field in this
struct is mainline-only (heartbeat_service()'s deferred window/variance/
trust processing), so only this one field needed the qualifier.

Punch list item 4.5b complete.
Three-arch acceptance boot clean at unchanged -O0 (no behavior change
intended yet -- this is prep for enabling optimization, not the switch
itself).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
This commit is contained in:
Robert Allan James
2026-08-11 10:09:47 -04:00
co-authored by Claude Sonnet 5
parent 8f4348ec18
commit 5cbb04c60a
1 changed files with 8 additions and 1 deletions
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include/starkernel/timer.h
+8 -1
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@@ -87,7 +87,14 @@ typedef struct time_window {
*/ */
typedef struct time_trust_state { typedef struct time_trust_state {
/* Core counters */ /* Core counters */
uint64_t ticks; /* TIME-TICKS: monotonic heartbeat count */ volatile uint64_t ticks; /* TIME-TICKS: monotonic heartbeat count --
* written directly in ISR context
* (heartbeat_tick(), all three archs) and
* read directly by mainline
* (heartbeat_ticks()); genuinely
* concurrent, unlike every other field in
* this struct (FABRIC.md item 4.5a/4.5b,
* 2026-08-11). */
uint64_t last_tsc; /* TSC at last heartbeat */ uint64_t last_tsc; /* TSC at last heartbeat */
uint64_t expected_delta; /* Expected TSC ticks per heartbeat */ uint64_t expected_delta; /* Expected TSC ticks per heartbeat */