ARM: Make sure that software prefetch instructions can't change the state of the TLB

3 files changed, 13 insertions, 3 deletions

diff --git a/src/arch/arm/faults.hh b/src/arch/arm/faults.hh
index d8684792c..f9d25abdf 100644
--- a/src/arch/arm/faults.hh
+++ b/src/arch/arm/faults.hh
@@ -87,6 +87,12 @@ class ArmFault : public FaultBase
         MemoryAccessSynchronousParityError = 0x19,
         TranslationTableWalkPrtyErr0 = 0x1c,
         TranslationTableWalkPrtyErr1 = 0x1e,
+
+        // not a real fault. This is a status code
+        // to allow the translation function to inform
+        // the memory access function not to proceed
+        // for a Prefetch that misses in the TLB.
+        PrefetchTLBMiss
     };
 
     struct FaultVals
diff --git a/src/arch/arm/table_walker.cc b/src/arch/arm/table_walker.cc
index 6dcb387a3..1d363c66f 100644
--- a/src/arch/arm/table_walker.cc
+++ b/src/arch/arm/table_walker.cc
@@ -439,11 +439,10 @@ TableWalker::doL1Descriptor()
               * AccessFlag0
               */
 
-            currState->fault =
-                new DataAbort(currState->vaddr, NULL, currState->isWrite,
+            currState->fault = new DataAbort(currState->vaddr,
+                                    currState->l1Desc.domain(), currState->isWrite,
                                     ArmFault::AccessFlag0);
         }
-
         if (currState->l1Desc.supersection()) {
             panic("Haven't implemented supersections\n");
         }
diff --git a/src/arch/arm/tlb.cc b/src/arch/arm/tlb.cc
index da2a34084..a70a20518 100644
--- a/src/arch/arm/tlb.cc
+++ b/src/arch/arm/tlb.cc
@@ -409,6 +409,11 @@ TLB::translateFs(RequestPtr req, ThreadContext *tc, Mode mode,
 
     TlbEntry *te = lookup(vaddr, context_id);
     if (te == NULL) {
+        if (req->isPrefetch()){
+           //if the request is a prefetch don't attempt to fill the TLB
+           //or go any further with the memory access
+           return new PrefetchAbort(vaddr, ArmFault::PrefetchTLBMiss);
+        }
         // start translation table walk, pass variables rather than
         // re-retreaving in table walker for speed
         DPRINTF(TLB, "TLB Miss: Starting hardware table walker for %#x(%d)\n",