cpu,sim: Delegate PCEvent scheduling from Systems to ThreadContexts.

The System keeps track of what events are live so new ThreadContexts
can have the same set of events as the other ThreadContexts.

Change-Id: Id22bfa0af7592a43d97be1564ca067b08ac1de7c
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/22106
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/cpu/checker/cpu_impl.hh

@@ -412,7 +412,6 @@ Checker<Impl>::verify(const DynInstPtr &completed_inst)
             int count = 0;
             do {
                 oldpc = thread->instAddr();
-                system->pcEventQueue.service(oldpc, tc);
                 thread->pcEventQueue.service(oldpc, tc);
                 count++;
             } while (oldpc != thread->instAddr());

src/cpu/minor/execute.cc

@@ -841,7 +841,6 @@ Execute::tryPCEvents(ThreadID thread_id)
     Addr oldPC;
     do {
         oldPC = thread->instAddr();
-        cpu.system->pcEventQueue.service(oldPC, thread);
         cpu.threads[thread_id]->pcEventQueue.service(oldPC, thread);
         num_pc_event_checks++;
     } while (oldPC != thread->instAddr());

src/cpu/o3/commit_impl.hh

@@ -1112,8 +1112,6 @@ DefaultCommit<Impl>::commitInsts()
                            !thread[tid]->trapPending);
                     do {
                         oldpc = pc[tid].instAddr();
-                        cpu->system->pcEventQueue.service(
-                                oldpc, thread[tid]->getTC());
                         thread[tid]->pcEventQueue.service(
                                 oldpc, thread[tid]->getTC());
                         count++;

src/cpu/simple/base.cc

@@ -144,7 +144,6 @@ BaseSimpleCPU::checkPcEventQueue()
     Addr oldpc, pc = threadInfo[curThread]->thread->instAddr();
     do {
         oldpc = pc;
-        system->pcEventQueue.service(oldpc, threadContexts[curThread]);
         threadInfo[curThread]->thread->pcEventQueue.service(
                 oldpc, threadContexts[curThread]);
         pc = threadInfo[curThread]->thread->instAddr();

src/sim/system.cc

@@ -265,6 +265,8 @@ System::registerThreadContext(ThreadContext *tc, ContextID assigned)
              "Cannot have two CPUs with the same id (%d)\n", id);
 
     threadContexts[id] = tc;
+    for (auto *e: liveEvents)
+        tc->schedule(e);
 
 #if THE_ISA != NULL_ISA
     int port = getRemoteGDBPort();
@@ -295,13 +297,21 @@ System::registerThreadContext(ThreadContext *tc, ContextID assigned)
 bool
 System::schedule(PCEvent *event)
 {
-    return pcEventQueue.schedule(event);
+    bool all = true;
+    liveEvents.push_back(event);
+    for (auto *tc: threadContexts)
+        all = tc->schedule(event) && all;
+    return all;
 }
 
 bool
 System::remove(PCEvent *event)
 {
-    return pcEventQueue.remove(event);
+    bool all = true;
+    liveEvents.remove(event);
+    for (auto *tc: threadContexts)
+        all = tc->remove(event) && all;
+    return all;
 }
 
 int
@@ -363,6 +373,10 @@ System::replaceThreadContext(ThreadContext *tc, ContextID context_id)
               context_id, threadContexts.size());
     }
 
+    for (auto *e: liveEvents) {
+        threadContexts[context_id]->remove(e);
+        tc->schedule(e);
+    }
     threadContexts[context_id] = tc;
     if (context_id < remoteGDB.size())
         remoteGDB[context_id]->replaceThreadContext(tc);

src/sim/system.hh

@@ -99,6 +99,7 @@ class System : public SimObject, public PCEventScope
         { panic("SystemPort does not expect retry!\n"); }
     };
 
+    std::list<PCEvent *> liveEvents;
     SystemPort _systemPort;
 
   public:
@@ -186,8 +187,6 @@ class System : public SimObject, public PCEventScope
      */
     unsigned int cacheLineSize() const { return _cacheLineSize; }
 
-    PCEventQueue pcEventQueue;
-
     std::vector<ThreadContext *> threadContexts;
     const bool multiThread;