gem5: campaigns are now running without interruption

This change introduces a fake iobus device into gem5 to prevent
it from crashing on bogus I/O memory accesses.

Change-Id: Ie69e3191bdd917cc681269852937a5a3820a93fb

simulators/gem5/src/dev/fail_fake_device.cc

@@ -0,0 +1,70 @@
+#include "base/trace.hh"
+#include "debug/Fail.hh"
+#include "dev/fail_fake_device.hh"
+#include "mem/packet.hh"
+#include "mem/packet_access.hh"
+#include "sim/system.hh"
+
+#include "config/FailConfig.hpp"
+#include "sal/SALInst.hpp"
+
+using namespace std;
+
+FailFakeDevice::FailFakeDevice(Params *p)
+    : BasicPioDevice(p)
+{
+    if (!p->ret_bad_addr)
+        pioSize = p->pio_size;
+
+    retData8 = p->ret_data8;
+    retData16 = p->ret_data16;
+    retData32 = p->ret_data32;
+    retData64 = p->ret_data64;
+}
+
+Tick
+FailFakeDevice::read(PacketPtr pkt)
+{
+    pkt->allocate();
+    pkt->makeAtomicResponse();
+
+    DPRINTF(Fail, "[FAIL] dev/fail_fake_device.cc read(): fake response\n");
+
+    switch (pkt->getSize()) {
+        case sizeof(uint64_t):
+            pkt->set(retData64);
+            break;
+        case sizeof(uint32_t):
+            pkt->set(retData32);
+            break;
+        case sizeof(uint16_t):
+            pkt->set(retData16);
+            break;
+        case sizeof(uint8_t):
+            pkt->set(retData8);
+            break;
+        default:
+            if (params()->fake_mem)
+                std::memset(pkt->getPtr<uint8_t>(), 0, pkt->getSize());
+            else
+                panic("invalid access size! Device being accessed by cache?\n");
+    }
+
+    return pioDelay;
+}
+
+Tick
+FailFakeDevice::write(PacketPtr pkt)
+{
+    pkt->makeAtomicResponse();
+
+    DPRINTF(Fail, "[FAIL] dev/fail_fake_device.cc write(): fake response\n");
+
+    return pioDelay;
+}
+
+FailFakeDevice *
+FailFakeDeviceParams::create()
+{
+    return new FailFakeDevice(this);
+}