Make checker handle not executing the same instruction as the main CPU a little better.

Also add the option for the checker to update itself with the main CPU's state if it executes an instruction differently (so it will handle DMA timing errors properly).

--HG--
extra : convert_revision : 760d11ec1a249bc75e2807d320866b5d08c2b6f2

3 files changed, 46 insertions, 10 deletions

diff --git a/cpu/checker/cpu.cc b/cpu/checker/cpu.cc
index 41ff6e769..f195c8842 100644
--- a/cpu/checker/cpu.cc
+++ b/cpu/checker/cpu.cc
@@ -78,6 +78,7 @@ CheckerCPU::CheckerCPU(Params *p)
     changedPC = willChangePC = changedNextPC = false;
 
     exitOnError = p->exitOnError;
+    updateOnError = p->updateOnError;
 #if FULL_SYSTEM
     itb = p->itb;
     dtb = p->dtb;
@@ -350,7 +351,12 @@ CheckerCPU::translateDataReadReq(MemReqPtr &req)
 {
     cpuXC->translateDataReadReq(req);
 
-    if (req->vaddr != unverifiedReq->vaddr) {
+    if (!unverifiedReq) {
+        warn("%lli: Request virtual addresses do not match! Inst: N/A, "
+             "checker: %#x",
+             curTick, req->vaddr);
+        return;
+    } else if (req->vaddr != unverifiedReq->vaddr) {
         warn("%lli: Request virtual addresses do not match! Inst: %#x, "
              "checker: %#x",
              curTick, unverifiedReq->vaddr, req->vaddr);
@@ -370,7 +376,12 @@ CheckerCPU::translateDataWriteReq(MemReqPtr &req)
 {
     cpuXC->translateDataWriteReq(req);
 
-    if (req->vaddr != unverifiedReq->vaddr) {
+    if (!unverifiedReq) {
+        warn("%lli: Request virtual addresses do not match! Inst: N/A, "
+             "checker: %#x",
+             curTick, req->vaddr);
+        return;
+    } else if (req->vaddr != unverifiedReq->vaddr) {
         warn("%lli: Request virtual addresses do not match! Inst: %#x, "
              "checker: %#x",
              curTick, unverifiedReq->vaddr, req->vaddr);
@@ -443,6 +454,8 @@ Checker<DynInstPtr>::tick(DynInstPtr &completed_inst)
         }
     }
 
+    unverifiedInst = inst;
+
     // Try to check all instructions that are completed, ending if we
     // run out of instructions to check or if an instruction is not
     // yet completed.
@@ -516,7 +529,7 @@ Checker<DynInstPtr>::tick(DynInstPtr &completed_inst)
                 cpuXC->setPC(cpuXC->readNextPC());
                 cpuXC->setNextPC(cpuXC->readNextPC() + sizeof(MachInst));
 
-                return;
+                break;
             } else {
                 // The instruction is carrying an ITB fault.  Handle
                 // the fault and see if our results match the CPU on
@@ -554,7 +567,8 @@ Checker<DynInstPtr>::tick(DynInstPtr &completed_inst)
 
             cpuXC->func_exe_inst++;
 
-            fault = curStaticInst->execute(this, NULL);
+            if (!inst->isUnverifiable())
+                fault = curStaticInst->execute(this, NULL);
 
             // Checks to make sure instrution results are correct.
             validateExecution(inst);
@@ -620,6 +634,7 @@ Checker<DynInstPtr>::tick(DynInstPtr &completed_inst)
             break;
         }
     }
+    unverifiedInst = NULL;
 }
 
 template <class DynInstPtr>
@@ -718,6 +733,13 @@ template <class DynInstPtr>
 void
 Checker<DynInstPtr>::validateState()
 {
+    if (updateThisCycle) {
+        warn("%lli: Instruction PC %#x results didn't match up, copying all "
+             "registers from main CPU", unverifiedInst->readPC());
+        // Heavy-weight copying of all registers
+        cpuXC->copyArchRegs(unverifiedInst->xcBase());
+        updateThisCycle = false;
+    }
 }
 
 template <class DynInstPtr>
diff --git a/cpu/checker/cpu.hh b/cpu/checker/cpu.hh
index 9fcd1037f..f48d1135a 100644
--- a/cpu/checker/cpu.hh
+++ b/cpu/checker/cpu.hh
@@ -98,6 +98,7 @@ class CheckerCPU : public BaseCPU
         Process *process;
 #endif
         bool exitOnError;
+        bool updateOnError;
     };
 
   public:
@@ -294,11 +295,8 @@ class CheckerCPU : public BaseCPU
     void syscall() { }
 #endif
 
-    void handleError()
-    {
-        if (exitOnError)
-            panic("Checker found error!");
-    }
+    virtual void handleError() = 0;
+
     bool checkFlags(MemReqPtr &req);
 
     ExecContext *xcBase() { return xcProxy; }
@@ -312,6 +310,7 @@ class CheckerCPU : public BaseCPU
     uint64_t newPC;
     bool changedNextPC;
     bool exitOnError;
+    bool updateOnError;
 
     InstSeqNum youngestSN;
 };
@@ -327,7 +326,7 @@ class Checker : public CheckerCPU
 {
   public:
     Checker(Params *p)
-        : CheckerCPU(p)
+        : CheckerCPU(p), updateThisCycle(false), unverifiedInst(NULL)
     { }
 
     void switchOut(Sampler *s);
@@ -339,6 +338,18 @@ class Checker : public CheckerCPU
     void validateExecution(DynInstPtr &inst);
     void validateState();
 
+    virtual void handleError()
+    {
+        if (exitOnError)
+            panic("Checker found error!");
+        else if (updateOnError)
+            updateThisCycle = true;
+    }
+
+    bool updateThisCycle;
+
+    DynInstPtr unverifiedInst;
+
     std::list<DynInstPtr> instList;
     typedef typename std::list<DynInstPtr>::iterator InstListIt;
     void dumpInsts();
diff --git a/cpu/checker/cpu_builder.cc b/cpu/checker/cpu_builder.cc
index d80daef97..802944e47 100644
--- a/cpu/checker/cpu_builder.cc
+++ b/cpu/checker/cpu_builder.cc
@@ -75,6 +75,7 @@ BEGIN_DECLARE_SIM_OBJECT_PARAMS(OzoneChecker)
 
     Param<bool> defer_registration;
     Param<bool> exitOnError;
+    Param<bool> updateOnError;
     Param<bool> function_trace;
     Param<Tick> function_trace_start;
 
@@ -108,6 +109,7 @@ BEGIN_INIT_SIM_OBJECT_PARAMS(OzoneChecker)
 
     INIT_PARAM(defer_registration, "defer system registration (for sampling)"),
     INIT_PARAM(exitOnError, "exit on error"),
+    INIT_PARAM(updateOnError, "Update the checker with the main CPU's state on error"),
     INIT_PARAM(function_trace, "Enable function trace"),
     INIT_PARAM(function_trace_start, "Cycle to start function trace")
 
@@ -124,6 +126,7 @@ CREATE_SIM_OBJECT(OzoneChecker)
     params->max_loads_any_thread = 0;
     params->max_loads_all_threads = 0;
     params->exitOnError = exitOnError;
+    params->updateOnError = updateOnError;
     params->deferRegistration = defer_registration;
     params->functionTrace = function_trace;
     params->functionTraceStart = function_trace_start;