config: Support full-system with SST's memory system

This patch adds an example configuration in ext/sst/tests/ that allows
an SST/gem5 instance to simulate a 4-core AArch64 system with SST's
memHierarchy components providing all the caches and memories.

configs/common/CacheConfig.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2012-2013 ARM Limited
+# Copyright (c) 2012-2013, 2015 ARM Limited
 # All rights reserved
 # 
 # The license below extends only to copyright in the software and shall
@@ -46,6 +46,13 @@ from m5.objects import *
 from Caches import *
 
 def config_cache(options, system):
+    if options.external_memory_system and (options.caches or options.l2cache):
+        print "External caches and internal caches are exclusive options.\n"
+        sys.exit(1)
+
+    if options.external_memory_system:
+        ExternalCache = ExternalCacheFactory(options.external_memory_system)
+
     if options.cpu_type == "arm_detailed":
         try:
             from O3_ARM_v7a import *
@@ -114,10 +121,50 @@ def config_cache(options, system):
                 system.cpu[i].dcache = dcache_real
                 system.cpu[i].dcache_mon = dcache_mon
 
+        elif options.external_memory_system:
+            # These port names are presented to whatever 'external' system
+            # gem5 is connecting to.  Its configuration will likely depend
+            # on these names.  For simplicity, we would advise configuring
+            # it to use this naming scheme; if this isn't possible, change
+            # the names below.
+            if buildEnv['TARGET_ISA'] in ['x86', 'arm']:
+                system.cpu[i].addPrivateSplitL1Caches(
+                        ExternalCache("cpu%d.icache" % i),
+                        ExternalCache("cpu%d.dcache" % i),
+                        ExternalCache("cpu%d.itb_walker_cache" % i),
+                        ExternalCache("cpu%d.dtb_walker_cache" % i))
+            else:
+                system.cpu[i].addPrivateSplitL1Caches(
+                        ExternalCache("cpu%d.icache" % i),
+                        ExternalCache("cpu%d.dcache" % i))
+
         system.cpu[i].createInterruptController()
         if options.l2cache:
             system.cpu[i].connectAllPorts(system.tol2bus, system.membus)
+        elif options.external_memory_system:
+            system.cpu[i].connectUncachedPorts(system.membus)
         else:
             system.cpu[i].connectAllPorts(system.membus)
 
     return system
+
+# ExternalSlave provides a "port", but when that port connects to a cache,
+# the connecting CPU SimObject wants to refer to its "cpu_side".
+# The 'ExternalCache' class provides this adaptation by rewriting the name,
+# eliminating distracting changes elsewhere in the config code.
+class ExternalCache(ExternalSlave):
+    def __getattr__(cls, attr):
+        if (attr == "cpu_side"):
+            attr = "port"
+        return super(ExternalSlave, cls).__getattr__(attr)
+
+    def __setattr__(cls, attr, value):
+        if (attr == "cpu_side"):
+            attr = "port"
+        return super(ExternalSlave, cls).__setattr__(attr, value)
+
+def ExternalCacheFactory(port_type):
+    def make(name):
+        return ExternalCache(port_data=name, port_type=port_type,
+                             addr_ranges=[AllMemory])
+    return make