arch-arm: Instantiate a single HTM checkpoint at ISA::startup

Change-Id: I48cc71dce607233f025387379507bcd485943dde
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/35016
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/arch/arm/insts/tme64ruby.cc

@@ -109,15 +109,16 @@ Tstart64::completeAcc(PacketPtr pkt, ExecContext *xc,
 
         // checkpointing occurs in the outer transaction only
         if (htm_depth == 1) {
-            auto new_cpt = new HTMCheckpoint();
+            BaseHTMCheckpointPtr& cpt = xc->tcBase()->getHtmCheckpointPtr();
 
-            new_cpt->save(tc);
-            new_cpt->destinationRegister(dest);
+            HTMCheckpoint *armcpt =
+                dynamic_cast<HTMCheckpoint*>(cpt.get());
+            assert(armcpt != nullptr);
+
+            armcpt->save(tc);
+            armcpt->destinationRegister(dest);
 
             ArmISA::globalClearExclusive(tc);
-
-            xc->tcBase()->setHtmCheckpointPtr(
-                std::unique_ptr<BaseHTMCheckpoint>(new_cpt));
         }
 
         xc->setIntRegOperand(this, 0, (Dest64) & mask(intWidth));

src/arch/arm/isa.cc

@@ -38,6 +38,7 @@
 #include "arch/arm/isa.hh"
 
 #include "arch/arm/faults.hh"
+#include "arch/arm/htm.hh"
 #include "arch/arm/interrupts.hh"
 #include "arch/arm/pmu.hh"
 #include "arch/arm/self_debug.hh"
@@ -439,9 +440,15 @@ ISA::startup()
 {
     BaseISA::startup();
 
-    if (tc)
+    if (tc) {
         setupThreadContext();
 
+        if (haveTME) {
+            std::unique_ptr<BaseHTMCheckpoint> cpt(new HTMCheckpoint());
+            tc->setHtmCheckpointPtr(std::move(cpt));
+        }
+    }
+
     afterStartup = true;
 }