CheckerCPU: Make CheckerCPU runtime selectable instead of compile selectable

Enables the CheckerCPU to be selected at runtime with the --checker option
from the configs/example/fs.py and configs/example/se.py configuration
files.  Also merges with the SE/FS changes.

37 files changed, 203 insertions, 306 deletions

diff --git a/src/arch/SConscript b/src/arch/SConscript
index 70a8de7fb..775aa1f41 100644
--- a/src/arch/SConscript
+++ b/src/arch/SConscript
@@ -94,8 +94,7 @@ isa_parser = File('isa_parser.py')
 # autogenerated files as targets and isa parser itself as a source.
 def isa_desc_emitter(target, source, env):
     cpu_models = list(env['CPU_MODELS'])
-    if env['USE_CHECKER']:
-        cpu_models.append('CheckerCPU')
+    cpu_models.append('CheckerCPU')
 
     # Several files are generated from the ISA description.
     # We always get the basic decoder and header file.
diff --git a/src/arch/arm/isa.cc b/src/arch/arm/isa.cc
index b8a0fe282..a452991aa 100644
--- a/src/arch/arm/isa.cc
+++ b/src/arch/arm/isa.cc
@@ -39,17 +39,13 @@
  */
 
 #include "arch/arm/isa.hh"
-#include "config/use_checker.hh"
+#include "cpu/checker/cpu.hh"
 #include "debug/Arm.hh"
 #include "debug/MiscRegs.hh"
 #include "sim/faults.hh"
 #include "sim/stat_control.hh"
 #include "sim/system.hh"
 
-#if USE_CHECKER
-#include "cpu/checker/cpu.hh"
-#endif
-
 namespace ArmISA
 {
 
@@ -294,11 +290,15 @@ ISA::setMiscReg(int misc_reg, const MiscReg &val, ThreadContext *tc)
         PCState pc = tc->pcState();
         pc.nextThumb(cpsr.t);
         pc.nextJazelle(cpsr.j);
-#if USE_CHECKER
-        tc->pcStateNoRecord(pc);
-#else
-        tc->pcState(pc);
-#endif //USE_CHECKER
+
+        // Follow slightly different semantics if a CheckerCPU object
+        // is connected
+        CheckerCPU *checker = tc->getCheckerCpuPtr();
+        if (checker) {
+            tc->pcStateNoRecord(pc);
+        } else {
+            tc->pcState(pc);
+        }
     } else if (misc_reg >= MISCREG_CP15_UNIMP_START &&
         misc_reg < MISCREG_CP15_END) {
         panic("Unimplemented CP15 register %s wrote with %#x.\n",
@@ -401,14 +401,13 @@ ISA::setMiscReg(int misc_reg, const MiscReg &val, ThreadContext *tc)
                     oc = sys->getThreadContext(x);
                     oc->getDTBPtr()->allCpusCaching();
                     oc->getITBPtr()->allCpusCaching();
-#if USE_CHECKER
-                    CheckerCPU *checker =
-                        dynamic_cast<CheckerCPU*>(oc->getCheckerCpuPtr());
+
+                    // If CheckerCPU is connected, need to notify it.
+                    CheckerCPU *checker = oc->getCheckerCpuPtr();
                     if (checker) {
                         checker->getDTBPtr()->allCpusCaching();
                         checker->getITBPtr()->allCpusCaching();
                     }
-#endif
                 }
                 return;
             }
@@ -426,14 +425,13 @@ ISA::setMiscReg(int misc_reg, const MiscReg &val, ThreadContext *tc)
                 assert(oc->getITBPtr() && oc->getDTBPtr());
                 oc->getITBPtr()->flushAll();
                 oc->getDTBPtr()->flushAll();
-#if USE_CHECKER
-                CheckerCPU *checker =
-                    dynamic_cast<CheckerCPU*>(oc->getCheckerCpuPtr());
+
+                // If CheckerCPU is connected, need to notify it of a flush
+                CheckerCPU *checker = oc->getCheckerCpuPtr();
                 if (checker) {
                     checker->getITBPtr()->flushAll();
                     checker->getDTBPtr()->flushAll();
                 }
-#endif
             }
             return;
           case MISCREG_ITLBIALL:
@@ -452,16 +450,14 @@ ISA::setMiscReg(int misc_reg, const MiscReg &val, ThreadContext *tc)
                         bits(newVal, 7,0));
                 oc->getDTBPtr()->flushMvaAsid(mbits(newVal, 31, 12),
                         bits(newVal, 7,0));
-#if USE_CHECKER
-                CheckerCPU *checker =
-                    dynamic_cast<CheckerCPU*>(oc->getCheckerCpuPtr());
+
+                CheckerCPU *checker = oc->getCheckerCpuPtr();
                 if (checker) {
                     checker->getITBPtr()->flushMvaAsid(mbits(newVal, 31, 12),
                             bits(newVal, 7,0));
                     checker->getDTBPtr()->flushMvaAsid(mbits(newVal, 31, 12),
                             bits(newVal, 7,0));
                 }
-#endif
             }
             return;
           case MISCREG_TLBIASIDIS:
@@ -472,14 +468,11 @@ ISA::setMiscReg(int misc_reg, const MiscReg &val, ThreadContext *tc)
                 assert(oc->getITBPtr() && oc->getDTBPtr());
                 oc->getITBPtr()->flushAsid(bits(newVal, 7,0));
                 oc->getDTBPtr()->flushAsid(bits(newVal, 7,0));
-#if USE_CHECKER
-                CheckerCPU *checker =
-                    dynamic_cast<CheckerCPU*>(oc->getCheckerCpuPtr());
+                CheckerCPU *checker = oc->getCheckerCpuPtr();
                 if (checker) {
                     checker->getITBPtr()->flushAsid(bits(newVal, 7,0));
                     checker->getDTBPtr()->flushAsid(bits(newVal, 7,0));
                 }
-#endif
             }
             return;
           case MISCREG_TLBIMVAAIS:
@@ -490,14 +483,12 @@ ISA::setMiscReg(int misc_reg, const MiscReg &val, ThreadContext *tc)
                 assert(oc->getITBPtr() && oc->getDTBPtr());
                 oc->getITBPtr()->flushMva(mbits(newVal, 31,12));
                 oc->getDTBPtr()->flushMva(mbits(newVal, 31,12));
-#if USE_CHECKER
-                CheckerCPU *checker =
-                    dynamic_cast<CheckerCPU*>(oc->getCheckerCpuPtr());
+
+                CheckerCPU *checker = oc->getCheckerCpuPtr();
                 if (checker) {
                     checker->getITBPtr()->flushMva(mbits(newVal, 31,12));
                     checker->getDTBPtr()->flushMva(mbits(newVal, 31,12));
                 }
-#endif
             }
             return;
           case MISCREG_ITLBIMVA:
diff --git a/src/arch/arm/utility.cc b/src/arch/arm/utility.cc
index 07932e676..28ffb6896 100644
--- a/src/arch/arm/utility.cc
+++ b/src/arch/arm/utility.cc
@@ -43,7 +43,7 @@
 #include "arch/arm/tlb.hh"
 #include "arch/arm/utility.hh"
 #include "arch/arm/vtophys.hh"
-#include "config/use_checker.hh"
+#include "cpu/checker/cpu.hh"
 #include "cpu/base.hh"
 #include "cpu/thread_context.hh"
 #include "mem/fs_translating_port_proxy.hh"
@@ -118,11 +118,13 @@ skipFunction(ThreadContext *tc)
 {
     TheISA::PCState newPC = tc->pcState();
     newPC.set(tc->readIntReg(ReturnAddressReg) & ~ULL(1));
-#if USE_CHECKER
-    tc->pcStateNoRecord(newPC);
-#else
-    tc->pcState(newPC);
-#endif
+
+    CheckerCPU *checker = tc->getCheckerCpuPtr();
+    if (checker) {
+        tc->pcStateNoRecord(newPC);
+    } else {
+        tc->pcState(newPC);
+    }
 }
 
 void
diff --git a/src/cpu/BaseCPU.py b/src/cpu/BaseCPU.py
index 63f454968..60d06b209 100644
--- a/src/cpu/BaseCPU.py
+++ b/src/cpu/BaseCPU.py
@@ -214,9 +214,10 @@ class BaseCPU(MemObject):
                                        "dtb_walker_cache.mem_side"]
             else:
                 self._cached_ports += ["itb.walker.port", "dtb.walker.port"]
+
             # Checker doesn't need its own tlb caches because it does
             # functional accesses only
-            if buildEnv['USE_CHECKER']:
+            if self.checker != NULL:
                 self._cached_ports += ["checker.itb.walker.port", \
                                        "checker.dtb.walker.port"]
 
@@ -227,3 +228,6 @@ class BaseCPU(MemObject):
         self.l2cache = l2c
         self.toL2Bus.master = self.l2cache.cpu_side
         self._cached_ports = ['l2cache.mem_side']
+
+    def addCheckerCpu(self):
+        pass
diff --git a/src/cpu/SConscript b/src/cpu/SConscript
index de59dcc24..922a2d9d7 100644
--- a/src/cpu/SConscript
+++ b/src/cpu/SConscript
@@ -69,10 +69,8 @@ virtual Fault completeAcc(uint8_t *data, %s *xc, Trace::InstRecord *traceData) c
 # it's enabled.  This isn't used for anything else other than StaticInst
 # headers.
 temp_cpu_list = env['CPU_MODELS'][:]
-
-if env['USE_CHECKER']:
-    temp_cpu_list.append('CheckerCPU')
-    SimObject('CheckerCPU.py')
+temp_cpu_list.append('CheckerCPU')
+SimObject('CheckerCPU.py')
 
 # Generate header.
 def gen_cpu_exec_signatures(target, source, env):
@@ -98,13 +96,8 @@ env.Command('static_inst_exec_sigs.hh', (),
             Action(gen_cpu_exec_signatures, gen_sigs_string,
                    varlist = temp_cpu_list))
 
-env.Depends('static_inst_exec_sigs.hh', Value(env['USE_CHECKER']))
 env.Depends('static_inst_exec_sigs.hh', Value(env['CPU_MODELS']))
 
-# List of suppported CPUs by the Checker.  Errors out if USE_CHECKER=True
-# and one of these are not being used.
-CheckerSupportedCPUList = ['O3CPU', 'OzoneCPU']
-
 SimObject('BaseCPU.py')
 SimObject('FuncUnit.py')
 SimObject('ExeTracer.py')
@@ -133,21 +126,10 @@ if env['TARGET_ISA'] == 'sparc':
     SimObject('LegionTrace.py')
     Source('legiontrace.cc')
 
-if env['USE_CHECKER']:
-    SimObject('DummyChecker.py')
-    Source('checker/cpu.cc')
-    Source('dummy_checker_builder.cc')
-    DebugFlag('Checker')
-    checker_supports = False
-    for i in CheckerSupportedCPUList:
-        if i in env['CPU_MODELS']:
-            checker_supports = True
-    if not checker_supports:
-        print "Checker only supports CPU models",
-        for i in CheckerSupportedCPUList:
-            print i,
-        print ", please set USE_CHECKER=False or use one of those CPU models"
-        Exit(1)
+SimObject('DummyChecker.py')
+Source('checker/cpu.cc')
+Source('dummy_checker_builder.cc')
+DebugFlag('Checker')
 
 DebugFlag('Activity')
 DebugFlag('Commit')
diff --git a/src/cpu/base.cc b/src/cpu/base.cc
index 0722f319d..5d5f704db 100644
--- a/src/cpu/base.cc
+++ b/src/cpu/base.cc
@@ -53,8 +53,8 @@
 #include "base/misc.hh"
 #include "base/output.hh"
 #include "base/trace.hh"
-#include "config/use_checker.hh"
 #include "cpu/base.hh"
+#include "cpu/checker/cpu.hh"
 #include "cpu/cpuevent.hh"
 #include "cpu/profile.hh"
 #include "cpu/thread_context.hh"
@@ -66,10 +66,6 @@
 #include "sim/sim_exit.hh"
 #include "sim/system.hh"
 
-#if USE_CHECKER
-#include "cpu/checker/cpu.hh"
-#endif
-
 // Hack
 #include "sim/stat_control.hh"
 
@@ -431,34 +427,33 @@ BaseCPU::takeOverFrom(BaseCPU *oldCPU)
             peer->setPeer(new_dtb_port);
         }
 
-#if USE_CHECKER
-        Port *old_checker_itb_port, *old_checker_dtb_port;
-        Port *new_checker_itb_port, *new_checker_dtb_port;
-
-        CheckerCPU *oldChecker =
-            dynamic_cast<CheckerCPU*>(oldTC->getCheckerCpuPtr());
-        CheckerCPU *newChecker =
-            dynamic_cast<CheckerCPU*>(newTC->getCheckerCpuPtr());
-        old_checker_itb_port = oldChecker->getITBPtr()->getPort();
-        old_checker_dtb_port = oldChecker->getDTBPtr()->getPort();
-        new_checker_itb_port = newChecker->getITBPtr()->getPort();
-        new_checker_dtb_port = newChecker->getDTBPtr()->getPort();
-
-        // Move over any table walker ports if they exist for checker
-        if (new_checker_itb_port && !new_checker_itb_port->isConnected()) {
-            assert(old_checker_itb_port);
-            Port *peer = old_checker_itb_port->getPeer();;
-            new_checker_itb_port->setPeer(peer);
-            peer->setPeer(new_checker_itb_port);
+        // Checker whether or not we have to transfer CheckerCPU
+        // objects over in the switch
+        CheckerCPU *oldChecker = oldTC->getCheckerCpuPtr();
+        CheckerCPU *newChecker = newTC->getCheckerCpuPtr();
+        if (oldChecker && newChecker) {
+            Port *old_checker_itb_port, *old_checker_dtb_port;
+            Port *new_checker_itb_port, *new_checker_dtb_port;
+
+            old_checker_itb_port = oldChecker->getITBPtr()->getPort();
+            old_checker_dtb_port = oldChecker->getDTBPtr()->getPort();
+            new_checker_itb_port = newChecker->getITBPtr()->getPort();
+            new_checker_dtb_port = newChecker->getDTBPtr()->getPort();
+
+            // Move over any table walker ports if they exist for checker
+            if (new_checker_itb_port && !new_checker_itb_port->isConnected()) {
+                assert(old_checker_itb_port);
+                Port *peer = old_checker_itb_port->getPeer();;
+                new_checker_itb_port->setPeer(peer);
+                peer->setPeer(new_checker_itb_port);
+            }
+            if (new_checker_dtb_port && !new_checker_dtb_port->isConnected()) {
+                assert(old_checker_dtb_port);
+                Port *peer = old_checker_dtb_port->getPeer();;
+                new_checker_dtb_port->setPeer(peer);
+                peer->setPeer(new_checker_dtb_port);
+            }
         }
-        if (new_checker_dtb_port && !new_checker_dtb_port->isConnected()) {
-            assert(old_checker_dtb_port);
-            Port *peer = old_checker_dtb_port->getPeer();;
-            new_checker_dtb_port->setPeer(peer);
-            peer->setPeer(new_checker_dtb_port);
-        }
-#endif
-
     }
 
     interrupts = oldCPU->interrupts;
diff --git a/src/cpu/base_dyn_inst.hh b/src/cpu/base_dyn_inst.hh
index 134725f70..7715ef57f 100644
--- a/src/cpu/base_dyn_inst.hh
+++ b/src/cpu/base_dyn_inst.hh
@@ -54,7 +54,7 @@
 #include "base/fast_alloc.hh"
 #include "base/trace.hh"
 #include "config/the_isa.hh"
-#include "config/use_checker.hh"
+#include "cpu/checker/cpu.hh"
 #include "cpu/o3/comm.hh"
 #include "cpu/exetrace.hh"
 #include "cpu/inst_seq.hh"
@@ -177,10 +177,8 @@ class BaseDynInst : public FastAlloc, public RefCounted
     RequestPtr savedSreqLow;
     RequestPtr savedSreqHigh;
 
-#if USE_CHECKER
     // Need a copy of main request pointer to verify on writes.
     RequestPtr reqToVerify;
-#endif //USE_CHECKER
 
     /** @todo: Consider making this private. */
   public:
@@ -896,12 +894,13 @@ BaseDynInst<Impl>::readMem(Addr addr, uint8_t *data,
             effAddr = req->getVaddr();
             effSize = size;
             effAddrValid = true;
-#if USE_CHECKER
-            if (reqToVerify != NULL) {
-                delete reqToVerify;
+
+            if (cpu->checker) {
+                if (reqToVerify != NULL) {
+                    delete reqToVerify;
+                }
+                reqToVerify = new Request(*req);
             }
-            reqToVerify = new Request(*req);
-#endif //USE_CHECKER
             fault = cpu->read(req, sreqLow, sreqHigh, data, lqIdx);
         } else {
             // Commit will have to clean up whatever happened.  Set this
@@ -957,12 +956,13 @@ BaseDynInst<Impl>::writeMem(uint8_t *data, unsigned size,
         effAddr = req->getVaddr();
         effSize = size;
         effAddrValid = true;
-#if USE_CHECKER
-        if (reqToVerify != NULL) {
-            delete reqToVerify;
+
+        if (cpu->checker) {
+            if (reqToVerify != NULL) {
+                delete reqToVerify;
+            }
+            reqToVerify = new Request(*req);
         }
-        reqToVerify = new Request(*req);
-#endif // USE_CHECKER
         fault = cpu->write(req, sreqLow, sreqHigh, data, sqIdx);
     }
 
diff --git a/src/cpu/base_dyn_inst_impl.hh b/src/cpu/base_dyn_inst_impl.hh
index 684be72b6..05f9b7767 100644
--- a/src/cpu/base_dyn_inst_impl.hh
+++ b/src/cpu/base_dyn_inst_impl.hh
@@ -48,7 +48,6 @@
 #include "base/cprintf.hh"
 #include "base/trace.hh"
 #include "config/the_isa.hh"
-#include "config/use_checker.hh"
 #include "cpu/base_dyn_inst.hh"
 #include "cpu/exetrace.hh"
 #include "debug/DynInst.hh"
@@ -139,9 +138,7 @@ BaseDynInst<Impl>::initVars()
     cpu->snList.insert(seqNum);
 #endif
 
-#if USE_CHECKER
     reqToVerify = NULL;
-#endif
 }
 
 template <class Impl>
@@ -168,10 +165,8 @@ BaseDynInst<Impl>::~BaseDynInst()
     cpu->snList.erase(seqNum);
 #endif
 
-#if USE_CHECKER
     if (reqToVerify)
         delete reqToVerify;
-#endif // USE_CHECKER
 }
 
 #ifdef DEBUG
diff --git a/src/cpu/checker/cpu.cc b/src/cpu/checker/cpu.cc
index b21ceeb92..66341b0e0 100644
--- a/src/cpu/checker/cpu.cc
+++ b/src/cpu/checker/cpu.cc
@@ -52,6 +52,7 @@
 #include "cpu/static_inst.hh"
 #include "cpu/thread_context.hh"
 #include "params/CheckerCPU.hh"
+#include "sim/full_system.hh"
 #include "sim/tlb.hh"
 
 using namespace std;
@@ -84,12 +85,7 @@ CheckerCPU::CheckerCPU(Params *p)
     dtb = p->dtb;
     systemPtr = NULL;
     workload = p->workload;
-    // XXX: This is a hack to get this to work some
-    thread = new SimpleThread(this, /* thread_num */ 0,
-            workload.size() ? workload[0] : NULL, itb, dtb);
-
-    tc = thread->getTC();
-    threadContexts.push_back(tc);
+    thread = NULL;
 
     updateOnError = true;
 }
@@ -103,22 +99,29 @@ CheckerCPU::setSystem(System *system)
 {
     systemPtr = system;
 
-    thread = new SimpleThread(this, 0, systemPtr, itb, dtb, false);
+    if (FullSystem) {
+        thread = new SimpleThread(this, 0, systemPtr, itb, dtb, false);
+    } else {
+        thread = new SimpleThread(this, 0, systemPtr,
+                                  workload.size() ? workload[0] : NULL,
+                                  itb, dtb);
+    }
 
     tc = thread->getTC();
     threadContexts.push_back(tc);
-    delete thread->kernelStats;
     thread->kernelStats = NULL;
+    // Thread should never be null after this
+    assert(thread != NULL);
 }
 
 void
-CheckerCPU::setIcachePort(Port *icache_port)
+CheckerCPU::setIcachePort(CpuPort *icache_port)
 {
     icachePort = icache_port;
 }
 
 void
-CheckerCPU::setDcachePort(Port *dcache_port)
+CheckerCPU::setDcachePort(CpuPort *dcache_port)
 {
     dcachePort = dcache_port;
 }
@@ -151,7 +154,7 @@ CheckerCPU::readMem(Addr addr, uint8_t *data, unsigned size, unsigned flags)
     // Need to account for multiple accesses like the Atomic and TimingSimple
     while (1) {
         memReq = new Request();
-        memReq->setVirt(0, addr, size, flags, thread->pcState().instAddr());
+        memReq->setVirt(0, addr, size, flags, masterId, thread->pcState().instAddr());
 
         // translate to physical address
         fault = dtb->translateFunctional(memReq, tc, BaseTLB::Read);
diff --git a/src/cpu/checker/cpu.hh b/src/cpu/checker/cpu.hh
index 54e446932..c3d3a379e 100644
--- a/src/cpu/checker/cpu.hh
+++ b/src/cpu/checker/cpu.hh
@@ -112,13 +112,25 @@ class CheckerCPU : public BaseCPU
 
     System *systemPtr;
 
-    void setIcachePort(Port *icache_port);
+    void setIcachePort(CpuPort *icache_port);
 
-    Port *icachePort;
+    CpuPort *icachePort;
 
-    void setDcachePort(Port *dcache_port);
+    void setDcachePort(CpuPort *dcache_port);
 
-    Port *dcachePort;
+    CpuPort *dcachePort;
+
+    CpuPort &getDataPort()
+    {
+        panic("Not supported on checker!");
+        return *dcachePort;
+    }
+
+    CpuPort &getInstPort()
+    {
+        panic("Not supported on checker!");
+        return *icachePort;
+    }
 
     virtual Port *getPort(const std::string &name, int idx)
     {
@@ -168,7 +180,12 @@ class CheckerCPU : public BaseCPU
     TheISA::TLB* getITBPtr() { return itb; }
     TheISA::TLB* getDTBPtr() { return dtb; }
 
-    virtual Counter totalInstructions() const
+    virtual Counter totalInsts() const
+    {
+        return 0;
+    }
+
+    virtual Counter totalOps() const
     {
         return 0;
     }
diff --git a/src/cpu/checker/cpu_impl.hh b/src/cpu/checker/cpu_impl.hh
index 5688ee674..4f3fa34d2 100644
--- a/src/cpu/checker/cpu_impl.hh
+++ b/src/cpu/checker/cpu_impl.hh
@@ -244,6 +244,7 @@ Checker<Impl>::verify(DynInstPtr &completed_inst)
                 memReq = new Request(unverifiedInst->threadNumber, fetch_PC,
                                      sizeof(MachInst),
                                      0,
+                                     masterId,
                                      fetch_PC, thread->contextId(),
                                      unverifiedInst->threadNumber);
                 memReq->setVirt(0, fetch_PC, sizeof(MachInst),
@@ -399,11 +400,13 @@ Checker<Impl>::verify(DynInstPtr &completed_inst)
 
         // Take any faults here
         if (fault != NoFault) {
-            fault->invoke(tc, curStaticInst);
-            willChangePC = true;
-            newPCState = thread->pcState();
-            DPRINTF(Checker, "Fault, PC is now %s\n", newPCState);
-            curMacroStaticInst = StaticInst::nullStaticInstPtr;
+            if (FullSystem) {
+                fault->invoke(tc, curStaticInst);
+                willChangePC = true;
+                newPCState = thread->pcState();
+                DPRINTF(Checker, "Fault, PC is now %s\n", newPCState);
+                curMacroStaticInst = StaticInst::nullStaticInstPtr;
+            }
         } else {
            advancePC(fault);
         }
diff --git a/src/cpu/checker/thread_context.hh b/src/cpu/checker/thread_context.hh
index 0d6fa6e2e..4aed0501c 100644
--- a/src/cpu/checker/thread_context.hh
+++ b/src/cpu/checker/thread_context.hh
@@ -112,7 +112,10 @@ class CheckerThreadContext : public ThreadContext
 
     TheISA::TLB *getDTBPtr() { return actualTC->getDTBPtr(); }
 
-    BaseCPU *getCheckerCpuPtr() { return checkerTC->getCpuPtr(); }
+    CheckerCPU *getCheckerCpuPtr()
+    {
+        return checkerCPU;
+    }
 
     Decoder *getDecoderPtr() { return actualTC->getDecoderPtr(); }
 
@@ -130,7 +133,6 @@ class CheckerThreadContext : public ThreadContext
     FSTranslatingPortProxy &getVirtProxy()
     { return actualTC->getVirtProxy(); }
 
-    //XXX: How does this work now?
     void initMemProxies(ThreadContext *tc)
     { actualTC->initMemProxies(tc); }
 
diff --git a/src/cpu/dummy_checker_builder.cc b/src/cpu/dummy_checker_builder.cc
index 0c83dabd0..fd2c9f74b 100644
--- a/src/cpu/dummy_checker_builder.cc
+++ b/src/cpu/dummy_checker_builder.cc
@@ -80,6 +80,7 @@ DummyCheckerParams::create()
     temp = max_insts_all_threads;
     temp = max_loads_any_thread;
     temp = max_loads_all_threads;
+    temp++;
     Tick temp2 = progress_interval;
     params->progress_interval = 0;
     temp2++;
diff --git a/src/cpu/o3/O3CPU.py b/src/cpu/o3/O3CPU.py
index acc7a9056..042c5e637 100644
--- a/src/cpu/o3/O3CPU.py
+++ b/src/cpu/o3/O3CPU.py
@@ -31,27 +31,12 @@ from m5.params import *
 from m5.proxy import *
 from BaseCPU import BaseCPU
 from FUPool import *
-
-if buildEnv['USE_CHECKER']:
-    from O3Checker import O3Checker
+from O3Checker import O3Checker
 
 class DerivO3CPU(BaseCPU):
     type = 'DerivO3CPU'
     activity = Param.Unsigned(0, "Initial count")
 
-    if buildEnv['USE_CHECKER']:
-        # FIXME: Shouldn't need to derefernce Parent.workload
-        #        Somewhere in the param parsing code
-        #        src/python/m5/params.py is and error that
-        #        has trouble converting the workload parameter properly.
-        checker = Param.BaseCPU(O3Checker(workload=Parent.workload[0],
-                                          exitOnError=False,
-                                          updateOnError=True,
-                                          warnOnlyOnLoadError=True),
-                                          "checker")
-        checker.itb = Parent.itb
-        checker.dtb = Parent.dtb
-
     cachePorts = Param.Unsigned(200, "Cache Ports")
 
     decodeToFetchDelay = Param.Unsigned(1, "Decode to fetch delay")
@@ -145,3 +130,18 @@ class DerivO3CPU(BaseCPU):
 
     needsTSO = Param.Bool(buildEnv['TARGET_ISA'] == 'x86',
                           "Enable TSO Memory model")
+
+    def addCheckerCpu(self):
+        if buildEnv['TARGET_ISA'] in ['arm']:
+            from ArmTLB import ArmTLB
+
+            self.checker = O3Checker(workload=self.workload,
+                                     exitOnError=False,
+                                     updateOnError=True,
+                                     warnOnlyOnLoadError=True)
+            self.checker.itb = ArmTLB(size = self.itb.size)
+            self.checker.dtb = ArmTLB(size = self.dtb.size)
+
+        else:
+            print "ERROR: Checker only supported under ARM ISA!"
+            exit(1)
diff --git a/src/cpu/o3/SConscript b/src/cpu/o3/SConscript
index 8ed337c25..8ca32c898 100755
--- a/src/cpu/o3/SConscript
+++ b/src/cpu/o3/SConscript
@@ -78,6 +78,5 @@ if 'O3CPU' in env['CPU_MODELS']:
         'IQ', 'ROB', 'FreeList', 'LSQ', 'LSQUnit', 'StoreSet', 'MemDepUnit',
         'DynInst', 'O3CPU', 'Activity', 'Scoreboard', 'Writeback' ])
 
-    if env['USE_CHECKER']:
-        SimObject('O3Checker.py')
-        Source('checker_builder.cc')
+    SimObject('O3Checker.py')
+    Source('checker_builder.cc')
diff --git a/src/cpu/o3/checker_builder.cc b/src/cpu/o3/checker_builder.cc
index 72b50d104..757b1a87f 100644
--- a/src/cpu/o3/checker_builder.cc
+++ b/src/cpu/o3/checker_builder.cc
@@ -92,6 +92,7 @@ O3CheckerParams::create()
     temp = max_insts_all_threads;
     temp = max_loads_any_thread;
     temp = max_loads_all_threads;
+    temp++;
     Tick temp2 = progress_interval;
     params->progress_interval = 0;
     temp2++;
diff --git a/src/cpu/o3/commit_impl.hh b/src/cpu/o3/commit_impl.hh
index bb82c37a8..ce023e665 100644
--- a/src/cpu/o3/commit_impl.hh
+++ b/src/cpu/o3/commit_impl.hh
@@ -48,7 +48,7 @@
 #include "base/loader/symtab.hh"
 #include "base/cp_annotate.hh"
 #include "config/the_isa.hh"
-#include "config/use_checker.hh"
+#include "cpu/checker/cpu.hh"
 #include "cpu/o3/commit.hh"
 #include "cpu/o3/thread_state.hh"
 #include "cpu/base.hh"
@@ -63,10 +63,6 @@
 #include "sim/faults.hh"
 #include "sim/full_system.hh"
 
-#if USE_CHECKER
-#include "cpu/checker/cpu.hh"
-#endif
-
 using namespace std;
 
 template <class Impl>
@@ -737,11 +733,9 @@ DefaultCommit<Impl>::handleInterrupt()
         assert(!thread[0]->inSyscall);
         thread[0]->inSyscall = true;
 
-#if USE_CHECKER
         if (cpu->checker) {
             cpu->checker->handlePendingInt();
         }
-#endif
 
         // CPU will handle interrupt.
         cpu->processInterrupts(interrupt);
@@ -1143,13 +1137,11 @@ DefaultCommit<Impl>::commitHead(DynInstPtr &head_inst, unsigned inst_num)
         head_inst->setCompleted();
     }
 
-#if USE_CHECKER
     // Use checker prior to updating anything due to traps or PC
     // based events.
     if (cpu->checker) {
         cpu->checker->verify(head_inst);
     }
-#endif
 
     if (inst_fault != NoFault) {
         DPRINTF(Commit, "Inst [sn:%lli] PC %s has a fault\n",
@@ -1162,12 +1154,10 @@ DefaultCommit<Impl>::commitHead(DynInstPtr &head_inst, unsigned inst_num)
 
         head_inst->setCompleted();
 
-#if USE_CHECKER
         if (cpu->checker) {
             // Need to check the instruction before its fault is processed
             cpu->checker->verify(head_inst);
         }
-#endif
 
         assert(!thread[tid]->inSyscall);
 
diff --git a/src/cpu/o3/cpu.cc b/src/cpu/o3/cpu.cc
index bf2cc80e3..f68b500ea 100644
--- a/src/cpu/o3/cpu.cc
+++ b/src/cpu/o3/cpu.cc
@@ -45,7 +45,8 @@
 
 #include "arch/kernel_stats.hh"
 #include "config/the_isa.hh"
-#include "config/use_checker.hh"
+#include "cpu/checker/cpu.hh"
+#include "cpu/checker/thread_context.hh"
 #include "cpu/o3/cpu.hh"
 #include "cpu/o3/isa_specific.hh"
 #include "cpu/o3/thread_context.hh"
@@ -63,11 +64,6 @@
 #include "sim/stat_control.hh"
 #include "sim/system.hh"
 
-#if USE_CHECKER
-#include "cpu/checker/cpu.hh"
-#include "cpu/checker/thread_context.hh"
-#endif
-
 #if THE_ISA == ALPHA_ISA
 #include "arch/alpha/osfpal.hh"
 #include "debug/Activity.hh"
@@ -263,7 +259,6 @@ FullO3CPU<Impl>::FullO3CPU(DerivO3CPUParams *params)
         _status = Idle;
     }
 
-#if USE_CHECKER
     if (params->checker) {
         BaseCPU *temp_checker = params->checker;
         checker = dynamic_cast<Checker<Impl> *>(temp_checker);
@@ -272,7 +267,6 @@ FullO3CPU<Impl>::FullO3CPU(DerivO3CPUParams *params)
     } else {
         checker = NULL;
     }
-#endif // USE_CHECKER
 
     if (!FullSystem) {
         thread.resize(numThreads);
@@ -438,12 +432,10 @@ FullO3CPU<Impl>::FullO3CPU(DerivO3CPUParams *params)
 
         // If we're using a checker, then the TC should be the
         // CheckerThreadContext.
-#if USE_CHECKER
         if (params->checker) {
             tc = new CheckerThreadContext<O3ThreadContext<Impl> >(
                 o3_tc, this->checker);
         }
-#endif
 
         o3_tc->cpu = (typename Impl::O3CPU *)(this);
         assert(o3_tc->cpu);
@@ -1207,10 +1199,10 @@ FullO3CPU<Impl>::switchOut()
     }
 
     _status = SwitchedOut;
-#if USE_CHECKER
+
     if (checker)
         checker->switchOut();
-#endif
+
     if (tickEvent.scheduled())
         tickEvent.squash();
 }
diff --git a/src/cpu/o3/cpu.hh b/src/cpu/o3/cpu.hh
index f48c0f0f2..42e9f01f9 100644
--- a/src/cpu/o3/cpu.hh
+++ b/src/cpu/o3/cpu.hh
@@ -55,7 +55,6 @@
 #include "arch/types.hh"
 #include "base/statistics.hh"
 #include "config/the_isa.hh"
-#include "config/use_checker.hh"
 #include "cpu/o3/comm.hh"
 #include "cpu/o3/cpu_policy.hh"
 #include "cpu/o3/scoreboard.hh"
@@ -720,13 +719,11 @@ class FullO3CPU : public BaseO3CPU
     /** The global sequence number counter. */
     InstSeqNum globalSeqNum;//[Impl::MaxThreads];
 
-#if USE_CHECKER
     /** Pointer to the checker, which can dynamically verify
      * instruction results at run time.  This can be set to NULL if it
      * is not being used.
      */
     Checker<Impl> *checker;
-#endif
 
     /** Pointer to the system. */
     System *system;
diff --git a/src/cpu/o3/cpu_builder.cc b/src/cpu/o3/cpu_builder.cc
index 296ad1793..71cebce05 100644
--- a/src/cpu/o3/cpu_builder.cc
+++ b/src/cpu/o3/cpu_builder.cc
@@ -30,7 +30,6 @@
 
 #include <string>
 
-#include "config/use_checker.hh"
 #include "cpu/o3/cpu.hh"
 #include "cpu/o3/impl.hh"
 #include "params/DerivO3CPU.hh"
diff --git a/src/cpu/o3/dyn_inst_impl.hh b/src/cpu/o3/dyn_inst_impl.hh
index ed1e374e8..2870d40fe 100644
--- a/src/cpu/o3/dyn_inst_impl.hh
+++ b/src/cpu/o3/dyn_inst_impl.hh
@@ -41,7 +41,6 @@
  */
 
 #include "base/cp_annotate.hh"
-#include "config/use_checker.hh"
 #include "cpu/o3/dyn_inst.hh"
 #include "sim/full_system.hh"
 
@@ -138,11 +137,12 @@ BaseO3DynInst<Impl>::completeAcc(PacketPtr pkt)
     bool in_syscall = this->thread->inSyscall;
     this->thread->inSyscall = true;
 
-#if USE_CHECKER
-    if (this->isStoreConditional()) {
-       this->reqToVerify->setExtraData(pkt->req->getExtraData());
+    if (this->cpu->checker) {
+        if (this->isStoreConditional()) {
+            this->reqToVerify->setExtraData(pkt->req->getExtraData());
+        }
     }
-#endif
+
     this->fault = this->staticInst->completeAcc(pkt, this, this->traceData);
 
     this->thread->inSyscall = in_syscall;
diff --git a/src/cpu/o3/fetch_impl.hh b/src/cpu/o3/fetch_impl.hh
index 1271ea481..60b11080d 100644
--- a/src/cpu/o3/fetch_impl.hh
+++ b/src/cpu/o3/fetch_impl.hh
@@ -53,8 +53,8 @@
 #include "arch/vtophys.hh"
 #include "base/types.hh"
 #include "config/the_isa.hh"
-#include "config/use_checker.hh"
 #include "cpu/base.hh"
+//#include "cpu/checker/cpu.hh"
 #include "cpu/o3/fetch.hh"
 #include "cpu/exetrace.hh"
 #include "debug/Activity.hh"
@@ -68,10 +68,6 @@
 #include "sim/full_system.hh"
 #include "sim/system.hh"
 
-#if USE_CHECKER
-#include "cpu/checker/cpu.hh"
-#endif // USE_CHECKER
-
 using namespace std;
 
 template<class Impl>
diff --git a/src/cpu/o3/iew_impl.hh b/src/cpu/o3/iew_impl.hh
index 209ad317b..4aaa321c5 100644
--- a/src/cpu/o3/iew_impl.hh
+++ b/src/cpu/o3/iew_impl.hh
@@ -48,7 +48,7 @@
 
 #include "arch/utility.hh"
 #include "config/the_isa.hh"
-#include "config/use_checker.hh"
+#include "cpu/checker/cpu.hh"
 #include "cpu/o3/fu_pool.hh"
 #include "cpu/o3/iew.hh"
 #include "cpu/timebuf.hh"
@@ -57,10 +57,6 @@
 #include "debug/IEW.hh"
 #include "params/DerivO3CPU.hh"
 
-#if USE_CHECKER
-#include "cpu/checker/cpu.hh"
-#endif // USE_CHECKER
-
 using namespace std;
 
 template<class Impl>
@@ -299,12 +295,10 @@ DefaultIEW<Impl>::initStage()
             ldstQueue.numFreeEntries(tid);
     }
 
-// Initialize the checker's dcache port here
-#if USE_CHECKER
+    // Initialize the checker's dcache port here
     if (cpu->checker) {
         cpu->checker->setDcachePort(&cpu->getDataPort());
-     }
-#endif
+    }
 
     cpu->activateStage(O3CPU::IEWIdx);
 }
diff --git a/src/cpu/o3/lsq_unit_impl.hh b/src/cpu/o3/lsq_unit_impl.hh
index facd88597..d0a630f6d 100644
--- a/src/cpu/o3/lsq_unit_impl.hh
+++ b/src/cpu/o3/lsq_unit_impl.hh
@@ -45,6 +45,7 @@
 #include "arch/locked_mem.hh"
 #include "base/str.hh"
 #include "config/the_isa.hh"
+#include "cpu/checker/cpu.hh"
 #include "cpu/o3/lsq.hh"
 #include "cpu/o3/lsq_unit.hh"
 #include "debug/Activity.hh"
@@ -53,10 +54,6 @@
 #include "mem/packet.hh"
 #include "mem/request.hh"
 
-#if USE_CHECKER
-#include "cpu/checker/cpu.hh"
-#endif
-
 template<class Impl>
 LSQUnit<Impl>::WritebackEvent::WritebackEvent(DynInstPtr &_inst, PacketPtr _pkt,
                                               LSQUnit *lsq_ptr)
@@ -871,11 +868,12 @@ LSQUnit<Impl>::writebackStores()
                         inst->seqNum);
                 WritebackEvent *wb = new WritebackEvent(inst, data_pkt, this);
                 cpu->schedule(wb, curTick() + 1);
-#if USE_CHECKER
-                // Make sure to set the LLSC data for verification
-                inst->reqToVerify->setExtraData(0);
-                inst->completeAcc(data_pkt);
-#endif
+                if (cpu->checker) {
+                    // Make sure to set the LLSC data for verification
+                    // if checker is loaded
+                    inst->reqToVerify->setExtraData(0);
+                    inst->completeAcc(data_pkt);
+                }
                 completeStore(storeWBIdx);
                 incrStIdx(storeWBIdx);
                 continue;
@@ -1083,11 +1081,10 @@ LSQUnit<Impl>::storePostSend(PacketPtr pkt)
         // only works so long as the checker doesn't try to
         // verify the value in memory for stores.
         storeQueue[storeWBIdx].inst->setCompleted();
-#if USE_CHECKER
+
         if (cpu->checker) {
             cpu->checker->verify(storeQueue[storeWBIdx].inst);
         }
-#endif
     }
 
     if (needsTSO) {
@@ -1174,11 +1171,9 @@ LSQUnit<Impl>::completeStore(int store_idx)
     // Tell the checker we've completed this instruction.  Some stores
     // may get reported twice to the checker, but the checker can
     // handle that case.
-#if USE_CHECKER
     if (cpu->checker) {
         cpu->checker->verify(storeQueue[store_idx].inst);
     }
-#endif
 }
 
 template <class Impl>
diff --git a/src/cpu/o3/thread_context.hh b/src/cpu/o3/thread_context.hh
index 8c32d1c05..ae76176ce 100755
--- a/src/cpu/o3/thread_context.hh
+++ b/src/cpu/o3/thread_context.hh
@@ -44,7 +44,6 @@
 #define __CPU_O3_THREAD_CONTEXT_HH__
 
 #include "config/the_isa.hh"
-#include "config/use_checker.hh"
 #include "cpu/o3/isa_specific.hh"
 #include "cpu/thread_context.hh"
 
@@ -84,9 +83,7 @@ class O3ThreadContext : public ThreadContext
     /** Returns a pointer to the DTB. */
     TheISA::TLB *getDTBPtr() { return cpu->dtb; }
 
-#if USE_CHECKER
-    BaseCPU *getCheckerCpuPtr() { return NULL; }
-#endif
+    CheckerCPU *getCheckerCpuPtr() { return NULL; }
 
     Decoder *getDecoderPtr() { return &cpu->fetch.decoder; }
 
@@ -194,9 +191,7 @@ class O3ThreadContext : public ThreadContext
     /** Sets this thread's PC state. */
     virtual void pcState(const TheISA::PCState &val);
 
-#if USE_CHECKER
     virtual void pcStateNoRecord(const TheISA::PCState &val);
-#endif
 
     /** Reads this thread's PC. */
     virtual Addr instAddr()
diff --git a/src/cpu/o3/thread_context_impl.hh b/src/cpu/o3/thread_context_impl.hh
index ecc40bd14..13bfe32df 100755
--- a/src/cpu/o3/thread_context_impl.hh
+++ b/src/cpu/o3/thread_context_impl.hh
@@ -44,7 +44,6 @@
 #include "arch/kernel_stats.hh"
 #include "arch/registers.hh"
 #include "config/the_isa.hh"
-#include "config/use_checker.hh"
 #include "cpu/o3/thread_context.hh"
 #include "cpu/quiesce_event.hh"
 #include "debug/O3CPU.hh"
@@ -297,7 +296,6 @@ O3ThreadContext<Impl>::pcState(const TheISA::PCState &val)
     }
 }
 
-#if USE_CHECKER
 template <class Impl>
 void
 O3ThreadContext<Impl>::pcStateNoRecord(const TheISA::PCState &val)
@@ -309,7 +307,6 @@ O3ThreadContext<Impl>::pcStateNoRecord(const TheISA::PCState &val)
         cpu->squashFromTC(thread->threadId());
     }
 }
-#endif
 
 template <class Impl>
 int
diff --git a/src/cpu/ozone/OzoneCPU.py b/src/cpu/ozone/OzoneCPU.py
index 2c7b8475f..d50d8d715 100644
--- a/src/cpu/ozone/OzoneCPU.py
+++ b/src/cpu/ozone/OzoneCPU.py
@@ -29,18 +29,13 @@
 from m5.defines import buildEnv
 from m5.params import *
 from BaseCPU import BaseCPU
-
-if buildEnv['USE_CHECKER']:
-    from OzoneChecker import OzoneChecker
+from OzoneChecker import OzoneChecker
 
 class DerivOzoneCPU(BaseCPU):
     type = 'DerivOzoneCPU'
 
     numThreads = Param.Unsigned("number of HW thread contexts")
 
-    if buildEnv['USE_CHECKER']:
-        checker = Param.BaseCPU("Checker CPU")
-
     icache_port = Port("Instruction Port")
     dcache_port = Port("Data Port")
 
@@ -123,3 +118,7 @@ class DerivOzoneCPU(BaseCPU):
 
     function_trace = Param.Bool(False, "Enable function trace")
     function_trace_start = Param.Tick(0, "Cycle to start function trace")
+
+    # If the CheckerCPU is brought back to useability in the OzoneCPU, create a
+    # function here called addCheckerCpu() to create a non-NULL Checker and
+    # connect its TLBs (if needed)
diff --git a/src/cpu/ozone/SConscript b/src/cpu/ozone/SConscript
index d26410ac2..6c966eb66 100644
--- a/src/cpu/ozone/SConscript
+++ b/src/cpu/ozone/SConscript
@@ -53,6 +53,5 @@ if 'OzoneCPU' in env['CPU_MODELS']:
 
     CompoundFlag('OzoneCPUAll', [ 'BE', 'FE', 'IBE', 'OzoneLSQ', 'OzoneCPU' ])
 
-    if env['USE_CHECKER']:
-        SimObject('OzoneChecker.py')
-        Source('checker_builder.cc')
+    SimObject('OzoneChecker.py')
+    Source('checker_builder.cc')
diff --git a/src/cpu/ozone/cpu_impl.hh b/src/cpu/ozone/cpu_impl.hh
index 65545b6aa..b111d4425 100644
--- a/src/cpu/ozone/cpu_impl.hh
+++ b/src/cpu/ozone/cpu_impl.hh
@@ -38,7 +38,7 @@
 #include "base/callback.hh"
 #include "base/trace.hh"
 #include "config/the_isa.hh"
-#include "config/use_checker.hh"
+#include "cpu/checker/thread_context.hh"
 #include "cpu/ozone/cpu.hh"
 #include "cpu/base.hh"
 #include "cpu/exetrace.hh"
@@ -56,10 +56,6 @@
 #include "sim/stats.hh"
 #include "sim/system.hh"
 
-#if USE_CHECKER
-#include "cpu/checker/thread_context.hh"
-#endif
-
 using namespace TheISA;
 
 template <class Impl>
@@ -97,16 +93,12 @@ OzoneCPU<Impl>::OzoneCPU(Params *p)
     _status = Idle;
 
     if (p->checker) {
-#if USE_CHECKER
         BaseCPU *temp_checker = p->checker;
         checker = dynamic_cast<Checker<DynInstPtr> *>(temp_checker);
         checker->setSystem(p->system);
         checkerTC = new CheckerThreadContext<OzoneTC>(&ozoneTC, checker);
         thread.tc = checkerTC;
         tc = checkerTC;
-#else
-        panic("Checker enabled but not compiled in!");
-#endif
     } else {
         // If checker is not being used, then the xcProxy points
         // directly to the CPU's ExecContext.
@@ -215,10 +207,9 @@ OzoneCPU<Impl>::signalSwitched()
     if (++switchCount == 2) {
         backEnd->doSwitchOut();
         frontEnd->doSwitchOut();
-#if USE_CHECKER
+
         if (checker)
             checker->switchOut();
-#endif
 
         _status = SwitchedOut;
 #ifndef NDEBUG
diff --git a/src/cpu/ozone/front_end_impl.hh b/src/cpu/ozone/front_end_impl.hh
index e7255d75f..2c9c70872 100644
--- a/src/cpu/ozone/front_end_impl.hh
+++ b/src/cpu/ozone/front_end_impl.hh
@@ -32,7 +32,7 @@
 #include "arch/utility.hh"
 #include "base/statistics.hh"
 #include "config/the_isa.hh"
-#include "config/use_checker.hh"
+#include "cpu/checker/cpu.hh"
 #include "cpu/ozone/front_end.hh"
 #include "cpu/exetrace.hh"
 #include "cpu/thread_context.hh"
@@ -41,10 +41,6 @@
 #include "mem/request.hh"
 #include "sim/faults.hh"
 
-#if USE_CHECKER
-#include "cpu/checker/cpu.hh"
-#endif
-
 using namespace TheISA;
 
 template<class Impl>
@@ -137,11 +133,9 @@ FrontEnd<Impl>::setCPU(CPUType *cpu_ptr)
 
     icachePort.setName(this->name() + "-iport");
 
-#if USE_CHECKER
     if (cpu->checker) {
         cpu->checker->setIcachePort(&icachePort);
     }
-#endif
 }
 
 template <class Impl>
diff --git a/src/cpu/ozone/lw_back_end_impl.hh b/src/cpu/ozone/lw_back_end_impl.hh
index c06a58754..1570c86ee 100644
--- a/src/cpu/ozone/lw_back_end_impl.hh
+++ b/src/cpu/ozone/lw_back_end_impl.hh
@@ -29,14 +29,10 @@
  */
 
 #include "config/the_isa.hh"
-#include "config/use_checker.hh"
+#include "cpu/checker/cpu.hh"
 #include "cpu/ozone/lw_back_end.hh"
 #include "cpu/op_class.hh"
 
-#if USE_CHECKER
-#include "cpu/checker/cpu.hh"
-#endif
-
 template <class Impl>
 void
 LWBackEnd<Impl>::generateTrapEvent(Tick latency)
@@ -1133,11 +1129,9 @@ LWBackEnd<Impl>::commitInst(int inst_num)
 
     // Use checker prior to updating anything due to traps or PC
     // based events.
-#if USE_CHECKER
     if (checker) {
         checker->verify(inst);
     }
-#endif
 
     if (inst_fault != NoFault) {
         DPRINTF(BE, "Inst [sn:%lli] PC %#x has a fault\n",
@@ -1153,11 +1147,9 @@ LWBackEnd<Impl>::commitInst(int inst_num)
             DPRINTF(BE, "Will wait until instruction is head of commit group.\n");
             return false;
         }
-#if USE_CHECKER
         else if (checker && inst->isStore()) {
             checker->verify(inst);
         }
-#endif
 
         handleFault(inst_fault);
         return false;
diff --git a/src/cpu/ozone/lw_lsq_impl.hh b/src/cpu/ozone/lw_lsq_impl.hh
index d80cdcf8c..82d0b4e8b 100644
--- a/src/cpu/ozone/lw_lsq_impl.hh
+++ b/src/cpu/ozone/lw_lsq_impl.hh
@@ -30,7 +30,6 @@
 
 #include "base/str.hh"
 #include "config/the_isa.hh"
-#include "config/use_checker.hh"
 #include "cpu/checker/cpu.hh"
 #include "cpu/ozone/lw_lsq.hh"
 #include "sim/fault_fwd.hh"
@@ -181,11 +180,9 @@ OzoneLWLSQ<Impl>::setCPU(OzoneCPU *cpu_ptr)
     cpu = cpu_ptr;
     dcachePort.setName(this->name() + "-dport");
 
-#if USE_CHECKER
     if (cpu->checker) {
         cpu->checker->setDcachePort(&dcachePort);
     }
-#endif
 }
 
 template<class Impl>
@@ -846,11 +843,9 @@ OzoneLWLSQ<Impl>::storePostSend(PacketPtr pkt, DynInstPtr &inst)
         // only works so long as the checker doesn't try to
         // verify the value in memory for stores.
         inst->setCompleted();
-#if USE_CHECKER
         if (cpu->checker) {
             cpu->checker->verify(inst);
         }
-#endif
     }
 }
 
@@ -914,11 +909,9 @@ OzoneLWLSQ<Impl>::completeStore(DynInstPtr &inst)
     --stores;
 
     inst->setCompleted();
-#if USE_CHECKER
     if (cpu->checker) {
         cpu->checker->verify(inst);
     }
-#endif
 }
 
 template <class Impl>
diff --git a/src/cpu/simple/BaseSimpleCPU.py b/src/cpu/simple/BaseSimpleCPU.py
index ea2c642e6..d9b963890 100644
--- a/src/cpu/simple/BaseSimpleCPU.py
+++ b/src/cpu/simple/BaseSimpleCPU.py
@@ -29,15 +29,19 @@
 from m5.defines import buildEnv
 from m5.params import *
 from BaseCPU import BaseCPU
-
-if buildEnv['USE_CHECKER']:
-    from DummyChecker import DummyChecker
+from DummyChecker import DummyChecker
 
 class BaseSimpleCPU(BaseCPU):
     type = 'BaseSimpleCPU'
     abstract = True
 
-    if buildEnv['USE_CHECKER']:
-        checker = Param.BaseCPU(DummyChecker(), "checker")
-        checker.itb = BaseCPU.itb
-        checker.dtb = BaseCPU.dtb
+    def addCheckerCpu(self):
+        if buildEnv['TARGET_ISA'] in ['arm']:
+            from ArmTLB import ArmTLB
+
+            self.checker = DummyChecker(workload = self.workload)
+            self.checker.itb = ArmTLB(size = self.itb.size)
+            self.checker.dtb = ArmTLB(size = self.dtb.size)
+        else:
+            print "ERROR: Checker only supported under ARM ISA!"
+            exit(1)
diff --git a/src/cpu/simple/base.cc b/src/cpu/simple/base.cc
index eee28876d..a5951035e 100644
--- a/src/cpu/simple/base.cc
+++ b/src/cpu/simple/base.cc
@@ -55,9 +55,10 @@
 #include "base/trace.hh"
 #include "base/types.hh"
 #include "config/the_isa.hh"
-#include "config/use_checker.hh"
 #include "cpu/simple/base.hh"
 #include "cpu/base.hh"
+#include "cpu/checker/cpu.hh"
+#include "cpu/checker/thread_context.hh"
 #include "cpu/exetrace.hh"
 #include "cpu/profile.hh"
 #include "cpu/simple_thread.hh"
@@ -80,11 +81,6 @@
 #include "sim/stats.hh"
 #include "sim/system.hh"
 
-#if USE_CHECKER
-#include "cpu/checker/cpu.hh"
-#include "cpu/checker/thread_context.hh"
-#endif
-
 using namespace std;
 using namespace TheISA;
 
@@ -101,7 +97,6 @@ BaseSimpleCPU::BaseSimpleCPU(BaseSimpleCPUParams *p)
 
     tc = thread->getTC();
 
-#if USE_CHECKER
     if (p->checker) {
         BaseCPU *temp_checker = p->checker;
         checker = dynamic_cast<CheckerCPU *>(temp_checker);
@@ -112,7 +107,6 @@ BaseSimpleCPU::BaseSimpleCPU(BaseSimpleCPUParams *p)
     } else {
         checker = NULL;
     }
-#endif
 
     numInst = 0;
     startNumInst = 0;
diff --git a/src/cpu/simple/base.hh b/src/cpu/simple/base.hh
index 4b73a4519..67fbccf98 100644
--- a/src/cpu/simple/base.hh
+++ b/src/cpu/simple/base.hh
@@ -48,8 +48,8 @@
 #include "arch/predecoder.hh"
 #include "base/statistics.hh"
 #include "config/the_isa.hh"
-#include "config/use_checker.hh"
 #include "cpu/base.hh"
+#include "cpu/checker/cpu.hh"
 #include "cpu/decode.hh"
 #include "cpu/pc_event.hh"
 #include "cpu/simple_thread.hh"
@@ -61,10 +61,6 @@
 #include "sim/full_system.hh"
 #include "sim/system.hh"
 
-#if USE_CHECKER
-#include "cpu/checker/cpu.hh"
-#endif
-
 // forward declarations
 class Checkpoint;
 class Process;
@@ -128,9 +124,8 @@ class BaseSimpleCPU : public BaseCPU
      */
     ThreadContext *tc;
 
-#if USE_CHECKER
     CheckerCPU *checker;
-#endif
+
   protected:
 
     enum Status {
diff --git a/src/cpu/simple_thread.hh b/src/cpu/simple_thread.hh
index d12ee9a06..ceab53c79 100644
--- a/src/cpu/simple_thread.hh
+++ b/src/cpu/simple_thread.hh
@@ -51,7 +51,6 @@
 #include "arch/types.hh"
 #include "base/types.hh"
 #include "config/the_isa.hh"
-#include "config/use_checker.hh"
 #include "cpu/decode.hh"
 #include "cpu/thread_context.hh"
 #include "cpu/thread_state.hh"
@@ -66,7 +65,7 @@
 #include "sim/system.hh"
 
 class BaseCPU;
-
+class CheckerCPU;
 
 class FunctionProfile;
 class ProfileNode;
@@ -198,9 +197,7 @@ class SimpleThread : public ThreadState
 
     TheISA::TLB *getDTBPtr() { return dtb; }
 
-#if USE_CHECKER
-    BaseCPU *getCheckerCpuPtr() { return NULL; }
-#endif
+    CheckerCPU *getCheckerCpuPtr() { return NULL; }
 
     Decoder *getDecoderPtr() { return &decoder; }
 
@@ -307,13 +304,11 @@ class SimpleThread : public ThreadState
         _pcState = val;
     }
 
-#if USE_CHECKER
     void
     pcStateNoRecord(const TheISA::PCState &val)
     {
         _pcState = val;
     }
-#endif
 
     Addr
     instAddr()
diff --git a/src/cpu/thread_context.hh b/src/cpu/thread_context.hh
index 41941b262..119de1fe0 100644
--- a/src/cpu/thread_context.hh
+++ b/src/cpu/thread_context.hh
@@ -50,7 +50,6 @@
 #include "arch/types.hh"
 #include "base/types.hh"
 #include "config/the_isa.hh"
-#include "config/use_checker.hh"
 
 // @todo: Figure out a more architecture independent way to obtain the ITB and
 // DTB pointers.
@@ -59,6 +58,7 @@ namespace TheISA
     class TLB;
 }
 class BaseCPU;
+class CheckerCPU;
 class Checkpoint;
 class Decoder;
 class EndQuiesceEvent;
@@ -133,9 +133,7 @@ class ThreadContext
 
     virtual TheISA::TLB *getDTBPtr() = 0;
 
-#if USE_CHECKER
-    virtual BaseCPU *getCheckerCpuPtr() = 0;
-#endif
+    virtual CheckerCPU *getCheckerCpuPtr() = 0;
 
     virtual Decoder *getDecoderPtr() = 0;
 
@@ -215,9 +213,7 @@ class ThreadContext
 
     virtual void pcState(const TheISA::PCState &val) = 0;
 
-#if USE_CHECKER
     virtual void pcStateNoRecord(const TheISA::PCState &val) = 0;
-#endif
 
     virtual Addr instAddr() = 0;
 
@@ -308,9 +304,7 @@ class ProxyThreadContext : public ThreadContext
 
     TheISA::TLB *getDTBPtr() { return actualTC->getDTBPtr(); }
 
-#if USE_CHECKER
-    BaseCPU *getCheckerCpuPtr() { return actualTC->getCheckerCpuPtr(); }
-#endif
+    CheckerCPU *getCheckerCpuPtr() { return actualTC->getCheckerCpuPtr(); }
 
     Decoder *getDecoderPtr() { return actualTC->getDecoderPtr(); }
 
@@ -392,9 +386,7 @@ class ProxyThreadContext : public ThreadContext
 
     void pcState(const TheISA::PCState &val) { actualTC->pcState(val); }
 
-#if USE_CHECKER
     void pcStateNoRecord(const TheISA::PCState &val) { actualTC->pcState(val); }
-#endif
 
     Addr instAddr() { return actualTC->instAddr(); }
     Addr nextInstAddr() { return actualTC->nextInstAddr(); }