systemc: When stopping immediately, block new processes/updates.

When stopping immediately, we're supposed to finish the current
process but not run any other processes or go to the update phase. The
rest of the process could introduce new processes or request new
updates, so we need to make sure we block those if we're in the process
of stopping.

Change-Id: I9cc867d294cf171dfedb4b9d43fbc167c2057de8
Reviewed-on: https://gem5-review.googlesource.com/c/12466
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

2 files changed, 9 insertions, 1 deletions

diff --git a/src/systemc/core/scheduler.cc b/src/systemc/core/scheduler.cc
index eda4ed7e4..cf34fe8b7 100644
--- a/src/systemc/core/scheduler.cc
+++ b/src/systemc/core/scheduler.cc
@@ -44,7 +44,7 @@ Scheduler::Scheduler() :
     stopEvent(this, false, StopPriority),
     scMain(nullptr),
     starvationEvent(this, false, StarvationPriority),
-    _started(false), _paused(false), _stopped(false),
+    _started(false), _paused(false), _stopped(false), _stopNow(false),
     maxTickEvent(this, false, MaxTickPriority),
     _numCycles(0), _changeStamp(0), _current(nullptr), initDone(false),
     runOnce(false)
@@ -189,6 +189,9 @@ Scheduler::yield()
 void
 Scheduler::ready(Process *p)
 {
+    if (_stopNow)
+        return;
+
     // Clump methods together to minimize context switching.
     static bool cluster_methods = false;
 
@@ -277,6 +280,9 @@ Scheduler::runReady()
         _changeStamp++;
     }
 
+    if (_stopNow)
+        return;
+
     // The update phase.
     update();
 
@@ -383,6 +389,7 @@ Scheduler::scheduleStop(bool finish_delta)
         return;
 
     if (!finish_delta) {
+        _stopNow = true;
         // If we're not supposed to finish the delta cycle, flush all
         // pending activity.
         clear();
diff --git a/src/systemc/core/scheduler.hh b/src/systemc/core/scheduler.hh
index 924cfb29e..f0cbac43c 100644
--- a/src/systemc/core/scheduler.hh
+++ b/src/systemc/core/scheduler.hh
@@ -386,6 +386,7 @@ class Scheduler
     bool _started;
     bool _paused;
     bool _stopped;
+    bool _stopNow;
 
     Tick maxTick;
     Tick lastReadyTick;