cpu: Unify SimpleCPU and O3 CPU serialization code

The O3 CPU used to copy its thread context to a SimpleThread in order
to do serialization. This was a bit of a hack involving two static
SimpleThread instances and a magic constructor that was only used by
the O3 CPU.

This patch moves the ThreadContext serialization code into two global
procedures that, in addition to the normal serialization parameters,
take a ThreadContext reference as a parameter. This allows us to reuse
the serialization code in all ThreadContext implementations.

src/cpu/inorder/thread_context.cc

@@ -160,21 +160,6 @@ InOrderThreadContext::regStats(const std::string &name)
     }
 }
 
-
-void
-InOrderThreadContext::serialize(std::ostream &os)
-{
-    panic("serialize unimplemented");
-}
-
-
-void
-InOrderThreadContext::unserialize(Checkpoint *cp, const std::string &section)
-{
-    panic("unserialize unimplemented");
-}
-
-
 void
 InOrderThreadContext::copyArchRegs(ThreadContext *src_tc)
 {

src/cpu/inorder/thread_context.hh

@@ -191,12 +191,6 @@ class InOrderThreadContext : public ThreadContext
     /** Registers statistics associated with this TC. */
     void regStats(const std::string &name);
 
-    /** Serializes state. */
-    void serialize(std::ostream &os);
-
-    /** Unserializes state. */
-    void unserialize(Checkpoint *cp, const std::string &section);
-
     /** Returns this thread's ID number. */
     int getThreadNum() { return thread->threadId(); }
 

src/cpu/o3/cpu.cc

@@ -1097,16 +1097,9 @@ FullO3CPU<Impl>::serialize(std::ostream &os)
     nameOut(os, csprintf("%s.tickEvent", name()));
     tickEvent.serialize(os);
 
-    // Use SimpleThread's ability to checkpoint to make it easier to
-    // write out the registers.  Also make this static so it doesn't
-    // get instantiated multiple times (causes a panic in statistics).
-    static SimpleThread temp;
-
-    ThreadID size = thread.size();
-    for (ThreadID i = 0; i < size; i++) {
+    for (ThreadID i = 0; i < thread.size(); i++) {
         nameOut(os, csprintf("%s.xc.%i", name(), i));
-        temp.copyTC(thread[i]->getTC());
-        temp.serialize(os);
+        thread[i]->serialize(os);
     }
 }
 
@@ -1119,16 +1112,11 @@ FullO3CPU<Impl>::unserialize(Checkpoint *cp, const std::string &section)
     BaseCPU::unserialize(cp, section);
     tickEvent.unserialize(cp, csprintf("%s.tickEvent", section));
 
-    // Use SimpleThread's ability to checkpoint to make it easier to
-    // read in the registers.  Also make this static so it doesn't
-    // get instantiated multiple times (causes a panic in statistics).
-    static SimpleThread temp;
-
-    ThreadID size = thread.size();
-    for (ThreadID i = 0; i < size; i++) {
-        temp.copyTC(thread[i]->getTC());
-        temp.unserialize(cp, csprintf("%s.xc.%i", section, i));
-        thread[i]->getTC()->copyArchRegs(temp.getTC());
+    for (ThreadID i = 0; i < thread.size(); i++) {
+        thread[i]->unserialize(cp,
+                               csprintf("%s.xc.%i", section, i));
+        if (thread[i]->status() == ThreadContext::Active)
+            activateThread(i);
     }
 }
 

src/cpu/o3/thread_context.hh

@@ -153,11 +153,6 @@ class O3ThreadContext : public ThreadContext
     /** Registers statistics associated with this TC. */
     virtual void regStats(const std::string &name);
 
-    /** Serializes state. */
-    virtual void serialize(std::ostream &os);
-    /** Unserializes state. */
-    virtual void unserialize(Checkpoint *cp, const std::string &section);
-
     /** Reads the last tick that this thread was activated on. */
     virtual Tick readLastActivate();
     /** Reads the last tick that this thread was suspended on. */

src/cpu/o3/thread_context_impl.hh

@@ -158,22 +158,6 @@ O3ThreadContext<Impl>::regStats(const std::string &name)
     }
 }
 
-template <class Impl>
-void
-O3ThreadContext<Impl>::serialize(std::ostream &os)
-{
-    if (FullSystem && thread->kernelStats)
-        thread->kernelStats->serialize(os);
-}
-
-template <class Impl>
-void
-O3ThreadContext<Impl>::unserialize(Checkpoint *cp, const std::string &section)
-{
-    if (FullSystem && thread->kernelStats)
-        thread->kernelStats->unserialize(cp, section);
-}
-
 template <class Impl>
 Tick
 O3ThreadContext<Impl>::readLastActivate()

src/cpu/o3/thread_state.hh

@@ -1,4 +1,16 @@
 /*
+ * Copyright (c) 2012 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
  * Copyright (c) 2006 The Regents of The University of Michigan
  * All rights reserved.
  *
@@ -99,6 +111,27 @@ struct O3ThreadState : public ThreadState {
         profilePC = 3;
     }
 
+    void serialize(std::ostream &os)
+    {
+        ThreadState::serialize(os);
+        // Use the ThreadContext serialization helper to serialize the
+        // TC.
+        ::serialize(*tc, os);
+    }
+
+    void unserialize(Checkpoint *cp, const std::string &section)
+    {
+        // Prevent squashing - we don't have any instructions in
+        // flight that we need to squash since we just instantiated a
+        // clean system.
+        noSquashFromTC = true;
+        ThreadState::unserialize(cp, section);
+        // Use the ThreadContext serialization helper to unserialize
+        // the TC.
+        ::unserialize(*tc, cp, section);
+        noSquashFromTC = false;
+    }
+
     /** Pointer to the ThreadContext of this thread. */
     ThreadContext *tc;
 

src/cpu/simple_thread.cc

@@ -99,12 +99,6 @@ SimpleThread::SimpleThread(BaseCPU *_cpu, int _thread_num, System *_sys,
         kernelStats = new TheISA::Kernel::Statistics(system);
 }
 
-SimpleThread::SimpleThread()
-    : ThreadState(NULL, -1, NULL), isa(NULL)
-{
-    tc = new ProxyThreadContext<SimpleThread>(this);
-}
-
 SimpleThread::~SimpleThread()
 {
     delete tc;
@@ -175,10 +169,7 @@ void
 SimpleThread::serialize(ostream &os)
 {
     ThreadState::serialize(os);
-    SERIALIZE_ARRAY(floatRegs.i, TheISA::NumFloatRegs);
-    SERIALIZE_ARRAY(intRegs, TheISA::NumIntRegs);
-    _pcState.serialize(os);
-    // thread_num and cpu_id are deterministic from the config
+    ::serialize(*tc, os);
 }
 
 
@@ -186,10 +177,7 @@ void
 SimpleThread::unserialize(Checkpoint *cp, const std::string &section)
 {
     ThreadState::unserialize(cp, section);
-    UNSERIALIZE_ARRAY(floatRegs.i, TheISA::NumFloatRegs);
-    UNSERIALIZE_ARRAY(intRegs, TheISA::NumIntRegs);
-    _pcState.unserialize(cp, section);
-    // thread_num and cpu_id are deterministic from the config
+    ::unserialize(*tc, cp, section);
 }
 
 void

src/cpu/simple_thread.hh

@@ -140,8 +140,6 @@ class SimpleThread : public ThreadState
                  Process *_process, TheISA::TLB *_itb, TheISA::TLB *_dtb,
                  TheISA::ISA *_isa);
 
-    SimpleThread();
-
     virtual ~SimpleThread();
 
     virtual void takeOverFrom(ThreadContext *oldContext);

src/cpu/thread_context.cc

@@ -1,4 +1,16 @@
 /*
+ * Copyright (c) 2012 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
  * Copyright (c) 2006 The Regents of The University of Michigan
  * All rights reserved.
  *
@@ -78,3 +90,49 @@ ThreadContext::compare(ThreadContext *one, ThreadContext *two)
 
 
 }
+
+void
+serialize(ThreadContext &tc, std::ostream &os)
+{
+    using namespace TheISA;
+
+    FloatRegBits floatRegs[NumFloatRegs];
+    for (int i = 0; i < NumFloatRegs; ++i)
+        floatRegs[i] = tc.readFloatRegBitsFlat(i);
+    // This is a bit ugly, but needed to maintain backwards
+    // compatibility.
+    arrayParamOut(os, "floatRegs.i", floatRegs, NumFloatRegs);
+
+    IntReg intRegs[NumIntRegs];
+    for (int i = 0; i < NumIntRegs; ++i)
+        intRegs[i] = tc.readIntRegFlat(i);
+    SERIALIZE_ARRAY(intRegs, NumIntRegs);
+
+    tc.pcState().serialize(os);
+
+    // thread_num and cpu_id are deterministic from the config
+}
+
+void
+unserialize(ThreadContext &tc, Checkpoint *cp, const std::string &section)
+{
+    using namespace TheISA;
+
+    FloatRegBits floatRegs[NumFloatRegs];
+    // This is a bit ugly, but needed to maintain backwards
+    // compatibility.
+    arrayParamIn(cp, section, "floatRegs.i", floatRegs, NumFloatRegs);
+    for (int i = 0; i < NumFloatRegs; ++i)
+        tc.setFloatRegBitsFlat(i, floatRegs[i]);
+
+    IntReg intRegs[NumIntRegs];
+    UNSERIALIZE_ARRAY(intRegs, NumIntRegs);
+    for (int i = 0; i < NumIntRegs; ++i)
+        tc.setIntRegFlat(i, intRegs[i]);
+
+    PCState pcState;
+    pcState.unserialize(cp, section);
+    tc.pcState(pcState);
+
+    // thread_num and cpu_id are deterministic from the config
+}

src/cpu/thread_context.hh

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011 ARM Limited
+ * Copyright (c) 2011-2012 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -177,9 +177,6 @@ class ThreadContext
 
     virtual void regStats(const std::string &name) = 0;
 
-    virtual void serialize(std::ostream &os) = 0;
-    virtual void unserialize(Checkpoint *cp, const std::string &section) = 0;
-
     virtual EndQuiesceEvent *getQuiesceEvent() = 0;
 
     // Not necessarily the best location for these...
@@ -369,10 +366,6 @@ class ProxyThreadContext : public ThreadContext
 
     void regStats(const std::string &name) { actualTC->regStats(name); }
 
-    void serialize(std::ostream &os) { actualTC->serialize(os); }
-    void unserialize(Checkpoint *cp, const std::string &section)
-    { actualTC->unserialize(cp, section); }
-
     EndQuiesceEvent *getQuiesceEvent() { return actualTC->getQuiesceEvent(); }
 
     Tick readLastActivate() { return actualTC->readLastActivate(); }
@@ -473,4 +466,19 @@ class ProxyThreadContext : public ThreadContext
     { actualTC->setFloatRegBitsFlat(idx, val); }
 };
 
+/** @{ */
+/**
+ * Thread context serialization helpers
+ *
+ * These helper functions provide a way to the data in a
+ * ThreadContext. They are provided as separate helper function since
+ * implementing them as members of the ThreadContext interface would
+ * be confusing when the ThreadContext is exported via a proxy.
+ */
+
+void serialize(ThreadContext &tc, std::ostream &os);
+void unserialize(ThreadContext &tc, Checkpoint *cp, const std::string &section);
+
+/** @} */
+
 #endif