O3: Fixes fetch deadlock when the interrupt clears before CPU handles it.

When this condition occurs the cpu should restart the fetch stage to fetch from
the original execution path. Fault handling in the commit stage is cleaned up a
little bit so the control flow is simplier. Finally, if an instruction is being
used to carry a fault it isn't executed, so the fault propagates appropriately.

1 files changed, 7 insertions, 1 deletions

diff --git a/src/cpu/o3/iew_impl.hh b/src/cpu/o3/iew_impl.hh
index c809b93ab..2acb941e0 100644
--- a/src/cpu/o3/iew_impl.hh
+++ b/src/cpu/o3/iew_impl.hh
@@ -1255,7 +1255,13 @@ DefaultIEW<Impl>::executeInsts()
             }
 
         } else {
-            inst->execute();
+            // If the instruction has already faulted, then skip executing it.
+            // Such case can happen when it faulted during ITLB translation.
+            // If we execute the instruction (even if it's a nop) the fault
+            // will be replaced and we will lose it.
+            if (inst->getFault() == NoFault) {
+                inst->execute();
+            }
 
             inst->setExecuted();