configs: Add an elastic-trace-generating CPU

According to the original paper [1] the elastic trace generation process
requires a cpu with a big number of entries in the ROB, LQ and SQ, so
that there are no stalls due to resource limitation.

At the moment these numbers are copy pasted from the
CpuConfig.config_etrace method [2].

[1]: https://ieeexplore.ieee.org/document/7818336
[2]: https://github.com/gem5/gem5/blob/stable/\
    configs/common/CpuConfig.py#L40

Change-Id: I00fde49e5420e420a4eddb7b49de4b74360348c9
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Richard Cooper <richard.cooper@arm.com>

configs/common/cores/arm/O3_ARM_Etrace.py

@@ -0,0 +1,58 @@
+# Copyright (c) 2012, 2017-2018, 2023 Arm Limited
+# All rights reserved.
+#
+# The license below extends only to copyright in the software and shall
+# not be construed as granting a license to any other intellectual
+# property including but not limited to intellectual property relating
+# to a hardware implementation of the functionality of the software
+# licensed hereunder.  You may use the software subject to the license
+# terms below provided that you ensure that this notice is replicated
+# unmodified and in its entirety in all distributions of the software,
+# modified or unmodified, in source code or in binary form.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met: redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer;
+# redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution;
+# neither the name of the copyright holders nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+from m5.objects import *
+from .O3_ARM_v7a import O3_ARM_v7a_3
+
+# O3_ARM_v7a_3 adapted to generate elastic traces
+class O3_ARM_v7a_3_Etrace(O3_ARM_v7a_3):
+    # Make the number of entries in the ROB, LQ and SQ very
+    # large so that there are no stalls due to resource
+    # limitation as such stalls will get captured in the trace
+    # as compute delay. For replay, ROB, LQ and SQ sizes are
+    # modelled in the Trace CPU.
+    numROBEntries = 512
+    LQEntries = 128
+    SQEntries = 128
+
+    def attach_probe_listener(self, inst_trace_file, data_trace_file):
+        # Attach the elastic trace probe listener. Set the protobuf trace
+        # file names. Set the dependency window size equal to the cpu it
+        # is attached to.
+        self.traceListener = m5.objects.ElasticTrace(
+            instFetchTraceFile=inst_trace_file,
+            dataDepTraceFile=data_trace_file,
+            depWindowSize=3 * self.numROBEntries,
+        )