Do not use cross-node ksCurTime

The code using ksCurTime assumes that ksCurTime is up-to-date,
but this assumption is wrong for ksCurTime of other CPU cores.
Those can be quite some time in the past.

The implications of using NODE_STATE(ksCurTime) is that clocks
on all cores must be synchronous:

- Riscv is okay: The specification states: "The real-time clocks
  of all hardware threads in a single user application should be
  synchronized to within one tick of the real-time clock."
- x86 okay if not ancient when Invariant TSC is supported.
- aarch64 is okay.
- arm32: arm_global.h is okay. Exynos timer seems okay. am335x and
  omap3430 are single-core.

See also #854.

Signed-off-by: Indan Zupancic <Indan.Zupancic@mep-info.com>

include/kernel/sporadic.h

@@ -125,7 +125,7 @@ static inline bool_t refill_sufficient(sched_context_t *sc, ticks_t usage)
  */
 static inline bool_t refill_ready(sched_context_t *sc)
 {
-    return refill_head(sc)->rTime <= (NODE_STATE_ON_CORE(ksCurTime, sc->scCore) + getKernelWcetTicks());
+    return refill_head(sc)->rTime <= (NODE_STATE(ksCurTime) + getKernelWcetTicks());
 }
 
 /*

src/kernel/sporadic.c

@@ -167,7 +167,7 @@ void refill_new(sched_context_t *sc, word_t max_refills, ticks_t budget, ticks_t
     /* full budget available */
     refill_head(sc)->rAmount = budget;
     /* budget can be used from now */
-    refill_head(sc)->rTime = NODE_STATE_ON_CORE(ksCurTime, core);
+    refill_head(sc)->rTime = NODE_STATE(ksCurTime);
     maybe_add_empty_tail(sc);
     REFILL_SANITY_CHECK(sc, budget);
 }
@@ -194,7 +194,7 @@ void refill_update(sched_context_t *sc, ticks_t new_period, ticks_t new_budget,
     sc->scPeriod = new_period;
 
     if (refill_ready(sc)) {
-        refill_head(sc)->rTime = NODE_STATE_ON_CORE(ksCurTime, sc->scCore);
+        refill_head(sc)->rTime = NODE_STATE(ksCurTime);
     }
 
     if (refill_head(sc)->rAmount >= new_budget) {
@@ -327,7 +327,7 @@ void refill_unblock_check(sched_context_t *sc)
     /* advance earliest activation time to now */
     REFILL_SANITY_START(sc);
     if (refill_ready(sc)) {
-        refill_head(sc)->rTime = NODE_STATE_ON_CORE(ksCurTime, sc->scCore);
+        refill_head(sc)->rTime = NODE_STATE(ksCurTime);
         NODE_STATE(ksReprogram) = true;
 
         /* merge available replenishments */