sim: Move the draining interface into a separate base class

This patch moves the draining interface from SimObject to a separate
class that can be used by any object needing draining. However,
objects not visible to the Python code (i.e., objects not deriving
from SimObject) still depend on their parents informing them when to
drain. This patch also gets rid of the CountedDrainEvent (which isn't
really an event) and replaces it with a DrainManager.

4 files changed, 56 insertions, 43 deletions

diff --git a/src/cpu/simple/atomic.cc b/src/cpu/simple/atomic.cc
index 2d7afd221..e63d998a7 100644
--- a/src/cpu/simple/atomic.cc
+++ b/src/cpu/simple/atomic.cc
@@ -123,7 +123,7 @@ AtomicSimpleCPU::~AtomicSimpleCPU()
 void
 AtomicSimpleCPU::serialize(ostream &os)
 {
-    SimObject::State so_state = SimObject::getState();
+    Drainable::State so_state(getDrainState());
     SERIALIZE_ENUM(so_state);
     SERIALIZE_SCALAR(locked);
     BaseSimpleCPU::serialize(os);
@@ -134,15 +134,22 @@ AtomicSimpleCPU::serialize(ostream &os)
 void
 AtomicSimpleCPU::unserialize(Checkpoint *cp, const string &section)
 {
-    SimObject::State so_state;
+    Drainable::State so_state;
     UNSERIALIZE_ENUM(so_state);
     UNSERIALIZE_SCALAR(locked);
     BaseSimpleCPU::unserialize(cp, section);
     tickEvent.unserialize(cp, csprintf("%s.tickEvent", section));
 }
 
+unsigned int
+AtomicSimpleCPU::drain(DrainManager *drain_manager)
+{
+    setDrainState(Drainable::Drained);
+    return 0;
+}
+
 void
-AtomicSimpleCPU::resume()
+AtomicSimpleCPU::drainResume()
 {
     if (_status == Idle || _status == SwitchedOut)
         return;
@@ -150,7 +157,7 @@ AtomicSimpleCPU::resume()
     DPRINTF(SimpleCPU, "Resume\n");
     assert(system->getMemoryMode() == Enums::atomic);
 
-    changeState(SimObject::Running);
+    setDrainState(Drainable::Running);
     if (thread->status() == ThreadContext::Active) {
         if (!tickEvent.scheduled())
             schedule(tickEvent, nextCycle());
@@ -161,7 +168,7 @@ AtomicSimpleCPU::resume()
 void
 AtomicSimpleCPU::switchOut()
 {
-    assert(_status == Running || _status == Idle);
+    assert(_status == BaseSimpleCPU::Running || _status == Idle);
     _status = SwitchedOut;
 
     tickEvent.squash();
@@ -180,13 +187,14 @@ AtomicSimpleCPU::takeOverFrom(BaseCPU *oldCPU)
     ThreadID size = threadContexts.size();
     for (ThreadID i = 0; i < size; ++i) {
         ThreadContext *tc = threadContexts[i];
-        if (tc->status() == ThreadContext::Active && _status != Running) {
-            _status = Running;
+        if (tc->status() == ThreadContext::Active &&
+            _status != BaseSimpleCPU::Running) {
+            _status = BaseSimpleCPU::Running;
             schedule(tickEvent, nextCycle());
             break;
         }
     }
-    if (_status != Running) {
+    if (_status != BaseSimpleCPU::Running) {
         _status = Idle;
     }
     assert(threadContexts.size() == 1);
@@ -212,7 +220,7 @@ AtomicSimpleCPU::activateContext(ThreadID thread_num, Cycles delay)
 
     //Make sure ticks are still on multiples of cycles
     schedule(tickEvent, clockEdge(delay));
-    _status = Running;
+    _status = BaseSimpleCPU::Running;
 }
 
 
@@ -227,7 +235,7 @@ AtomicSimpleCPU::suspendContext(ThreadID thread_num)
     if (_status == Idle)
         return;
 
-    assert(_status == Running);
+    assert(_status == BaseSimpleCPU::Running);
 
     // tick event may not be scheduled if this gets called from inside
     // an instruction's execution, e.g. "quiesce"
diff --git a/src/cpu/simple/atomic.hh b/src/cpu/simple/atomic.hh
index d67ab67a5..94d2de081 100644
--- a/src/cpu/simple/atomic.hh
+++ b/src/cpu/simple/atomic.hh
@@ -122,7 +122,9 @@ class AtomicSimpleCPU : public BaseSimpleCPU
 
     virtual void serialize(std::ostream &os);
     virtual void unserialize(Checkpoint *cp, const std::string &section);
-    virtual void resume();
+
+    unsigned int drain(DrainManager *drain_manager);
+    void drainResume();
 
     void switchOut();
     void takeOverFrom(BaseCPU *oldCPU);
diff --git a/src/cpu/simple/timing.cc b/src/cpu/simple/timing.cc
index 15b277d53..41764302d 100644
--- a/src/cpu/simple/timing.cc
+++ b/src/cpu/simple/timing.cc
@@ -92,7 +92,7 @@ TimingSimpleCPU::TimingSimpleCPU(TimingSimpleCPUParams *p)
 {
     _status = Idle;
 
-    changeState(SimObject::Running);
+    setDrainState(Drainable::Running);
     system->totalNumInsts = 0;
 }
 
@@ -104,7 +104,7 @@ TimingSimpleCPU::~TimingSimpleCPU()
 void
 TimingSimpleCPU::serialize(ostream &os)
 {
-    SimObject::State so_state = SimObject::getState();
+    Drainable::State so_state(getDrainState());
     SERIALIZE_ENUM(so_state);
     BaseSimpleCPU::serialize(os);
 }
@@ -112,29 +112,31 @@ TimingSimpleCPU::serialize(ostream &os)
 void
 TimingSimpleCPU::unserialize(Checkpoint *cp, const string &section)
 {
-    SimObject::State so_state;
+    Drainable::State so_state;
     UNSERIALIZE_ENUM(so_state);
     BaseSimpleCPU::unserialize(cp, section);
 }
 
 unsigned int
-TimingSimpleCPU::drain(Event *drain_event)
+TimingSimpleCPU::drain(DrainManager *drain_manager)
 {
     // TimingSimpleCPU is ready to drain if it's not waiting for
     // an access to complete.
-    if (_status == Idle || _status == Running || _status == SwitchedOut) {
-        changeState(SimObject::Drained);
+    if (_status == Idle ||
+        _status == BaseSimpleCPU::Running ||
+        _status == SwitchedOut) {
+        setDrainState(Drainable::Drained);
         return 0;
     } else {
-        changeState(SimObject::Draining);
-        drainEvent = drain_event;
+        setDrainState(Drainable::Draining);
+        drainManager = drain_manager;
         DPRINTF(Drain, "CPU not drained\n");
         return 1;
     }
 }
 
 void
-TimingSimpleCPU::resume()
+TimingSimpleCPU::drainResume()
 {
     DPRINTF(SimpleCPU, "Resume\n");
     if (_status != SwitchedOut && _status != Idle) {
@@ -146,13 +148,13 @@ TimingSimpleCPU::resume()
         schedule(fetchEvent, nextCycle());
     }
 
-    changeState(SimObject::Running);
+    setDrainState(Drainable::Running);
 }
 
 void
 TimingSimpleCPU::switchOut()
 {
-    assert(_status == Running || _status == Idle);
+    assert(_status == BaseSimpleCPU::Running || _status == Idle);
     _status = SwitchedOut;
     numCycles += curCycle() - previousCycle;
 
@@ -172,13 +174,14 @@ TimingSimpleCPU::takeOverFrom(BaseCPU *oldCPU)
     // running and schedule its tick event.
     for (int i = 0; i < threadContexts.size(); ++i) {
         ThreadContext *tc = threadContexts[i];
-        if (tc->status() == ThreadContext::Active && _status != Running) {
-            _status = Running;
+        if (tc->status() == ThreadContext::Active &&
+            _status != BaseSimpleCPU::Running) {
+            _status = BaseSimpleCPU::Running;
             break;
         }
     }
 
-    if (_status != Running) {
+    if (_status != BaseSimpleCPU::Running) {
         _status = Idle;
     }
     assert(threadContexts.size() == 1);
@@ -197,7 +200,7 @@ TimingSimpleCPU::activateContext(ThreadID thread_num, Cycles delay)
     assert(_status == Idle);
 
     notIdleFraction++;
-    _status = Running;
+    _status = BaseSimpleCPU::Running;
 
     // kick things off by initiating the fetch of the next instruction
     schedule(fetchEvent, clockEdge(delay));
@@ -215,7 +218,7 @@ TimingSimpleCPU::suspendContext(ThreadID thread_num)
     if (_status == Idle)
         return;
 
-    assert(_status == Running);
+    assert(_status == BaseSimpleCPU::Running);
 
     // just change status to Idle... if status != Running,
     // completeInst() will not initiate fetch of next instruction.
@@ -330,7 +333,7 @@ TimingSimpleCPU::translationFault(Fault fault)
 
     postExecute();
 
-    if (getState() == SimObject::Draining) {
+    if (getDrainState() == Drainable::Draining) {
         advancePC(fault);
         completeDrain();
     } else {
@@ -511,7 +514,7 @@ TimingSimpleCPU::writeMem(uint8_t *data, unsigned size,
 void
 TimingSimpleCPU::finishTranslation(WholeTranslationState *state)
 {
-    _status = Running;
+    _status = BaseSimpleCPU::Running;
 
     if (state->getFault() != NoFault) {
         if (state->isPrefetch()) {
@@ -552,7 +555,7 @@ TimingSimpleCPU::fetch()
     bool needToFetch = !isRomMicroPC(pcState.microPC()) && !curMacroStaticInst;
 
     if (needToFetch) {
-        _status = Running;
+        _status = BaseSimpleCPU::Running;
         Request *ifetch_req = new Request();
         ifetch_req->setThreadContext(_cpuId, /* thread ID */ 0);
         setupFetchRequest(ifetch_req);
@@ -592,7 +595,7 @@ TimingSimpleCPU::sendFetch(Fault fault, RequestPtr req, ThreadContext *tc)
         DPRINTF(SimpleCPU, "Translation of addr %#x faulted\n", req->getVaddr());
         delete req;
         // fetch fault: advance directly to next instruction (fault handler)
-        _status = Running;
+        _status = BaseSimpleCPU::Running;
         advanceInst(fault);
     }
 
@@ -620,7 +623,7 @@ TimingSimpleCPU::advanceInst(Fault fault)
     if (!stayAtPC)
         advancePC(fault);
 
-    if (_status == Running) {
+    if (_status == BaseSimpleCPU::Running) {
         // kick off fetch of next instruction... callback from icache
         // response will cause that instruction to be executed,
         // keeping the CPU running.
@@ -641,12 +644,12 @@ TimingSimpleCPU::completeIfetch(PacketPtr pkt)
     assert(!pkt || !pkt->isError());
     assert(_status == IcacheWaitResponse);
 
-    _status = Running;
+    _status = BaseSimpleCPU::Running;
 
     numCycles += curCycle() - previousCycle;
     previousCycle = curCycle();
 
-    if (getState() == SimObject::Draining) {
+    if (getDrainState() == Drainable::Draining) {
         if (pkt) {
             delete pkt->req;
             delete pkt;
@@ -664,7 +667,7 @@ TimingSimpleCPU::completeIfetch(PacketPtr pkt)
         // If we're not running now the instruction will complete in a dcache
         // response callback or the instruction faulted and has started an
         // ifetch
-        if (_status == Running) {
+        if (_status == BaseSimpleCPU::Running) {
             if (fault != NoFault && traceData) {
                 // If there was a fault, we shouldn't trace this instruction.
                 delete traceData;
@@ -778,7 +781,7 @@ TimingSimpleCPU::completeDataAccess(PacketPtr pkt)
         }
     }
 
-    _status = Running;
+    _status = BaseSimpleCPU::Running;
 
     Fault fault = curStaticInst->completeAcc(pkt, this, traceData);
 
@@ -802,7 +805,7 @@ TimingSimpleCPU::completeDataAccess(PacketPtr pkt)
 
     postExecute();
 
-    if (getState() == SimObject::Draining) {
+    if (getDrainState() == Drainable::Draining) {
         advancePC(fault);
         completeDrain();
 
@@ -817,8 +820,8 @@ void
 TimingSimpleCPU::completeDrain()
 {
     DPRINTF(Drain, "CPU done draining, processing drain event\n");
-    changeState(SimObject::Drained);
-    drainEvent->process();
+    setDrainState(Drainable::Drained);
+    drainManager->signalDrainDone();
 }
 
 bool
diff --git a/src/cpu/simple/timing.hh b/src/cpu/simple/timing.hh
index a2570abe6..e7f5122d0 100644
--- a/src/cpu/simple/timing.hh
+++ b/src/cpu/simple/timing.hh
@@ -45,7 +45,7 @@ class TimingSimpleCPU : public BaseSimpleCPU
     virtual void init();
 
   public:
-    Event *drainEvent;
+    DrainManager *drainManager;
 
   private:
 
@@ -109,7 +109,7 @@ class TimingSimpleCPU : public BaseSimpleCPU
         void
         markDelayed()
         {
-            assert(cpu->_status == Running);
+            assert(cpu->_status == BaseSimpleCPU::Running);
             cpu->_status = ITBWaitResponse;
         }
 
@@ -249,8 +249,8 @@ class TimingSimpleCPU : public BaseSimpleCPU
     virtual void serialize(std::ostream &os);
     virtual void unserialize(Checkpoint *cp, const std::string &section);
 
-    virtual unsigned int drain(Event *drain_event);
-    virtual void resume();
+    unsigned int drain(DrainManager *drain_manager);
+    void drainResume();
 
     void switchOut();
     void takeOverFrom(BaseCPU *oldCPU);