arch-arm: SGI registers undecoded in AArch32

Change-Id: I64d3e639e1beaa507263637d59499aafeb5a19f8
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20612
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/arch/arm/miscregs.cc

@@ -962,6 +962,18 @@ decodeCP15Reg64(unsigned crm, unsigned opc1)
             return MISCREG_CNTHP_CVAL;
         }
         break;
+      case 12:
+        switch (opc1) {
+          case 0:
+            return MISCREG_ICC_SGI1R;
+          case 1:
+            return MISCREG_ICC_ASGI1R;
+          case 2:
+            return MISCREG_ICC_SGI0R;
+          default:
+            break;
+        }
+        break;
       case 15:
         if (opc1 == 0)
             return MISCREG_CPUMERRSR;