arm: Add a model of an ARM PMUv3

This class implements a subset of the ARM PMU v3 specification as
described in the ARMv8 reference manual. It supports most of the
features of the PMU, however the following features are known to be
missing:

 * Event filtering (e.g., from different privilege levels).
 * Access controls (the PMU currently ignores the execution level).
 * The chain counter (event no. 0x1E) is unimplemented.

The PMU itself does not implement any events, it merely provides an
interface for the configuration scripts to hook up probes that drive
events. Configuration scripts should call addEventProbe() to configure
custom events or high-level methods to configure architected
events. The Python implementation of addEventProbe() automatically
delays event type registration until after instantiation.

In order to support CPU switching and some combined counters (e.g.,
memory references synthesized from loads and stores), the PMU allows
multiple probes per event type. When creating a system that switches
between CPU models that share the same PMU, PMU events for all of the
CPU models can be registered with the PMU.

Kudos to Matt Horsnell for the initial gem5 implementation of the PMU.

1 files changed, 83 insertions, 0 deletions

diff --git a/src/arch/arm/ArmPMU.py b/src/arch/arm/ArmPMU.py
new file mode 100644
index 000000000..dc393be69
--- /dev/null
+++ b/src/arch/arm/ArmPMU.py
@@ -0,0 +1,83 @@
+# -*- mode:python -*-
+# Copyright (c) 2009-2014 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.
+#
+# Authors: Matt Horsnell
+#          Andreas Sandberg
+
+from m5.defines import buildEnv
+from m5.SimObject import SimObject
+from m5.params import *
+from m5.params import isNullPointer
+from m5.proxy import *
+
+class ArmPMU(SimObject):
+    type = 'ArmPMU'
+    cxx_class = 'ArmISA::PMU'
+    cxx_header = 'arch/arm/pmu.hh'
+
+    @classmethod
+    def export_methods(cls, code):
+        code('''
+      void addEventProbe(unsigned int id,
+                        SimObject *obj, const char *name);
+''')
+
+    # To prevent cycles in the configuration hierarchy, we don't keep
+    # a list of supported events as a configuration param. Instead, we
+    # keep them in a local list and register them using the
+    # addEventProbe interface when other SimObjects register their
+    # probe listeners.
+    _deferred_event_types = []
+    # Override the normal SimObject::regProbeListeners method and
+    # register deferred event handlers.
+    def regProbeListeners(self):
+        for event_id, obj, name in self._deferred_event_types:
+            self.getCCObject().addEventProbe(event_id, obj.getCCObject(), name)
+
+        self.getCCObject().regProbeListeners()
+
+    def addEventProbe(self, event_id, obj, *args):
+        """Add a probe-based event to the PMU if obj is not None."""
+
+        if obj is None:
+            return
+
+        for name in args:
+            self._deferred_event_types.append((event_id, obj, name))
+
+    platform = Param.Platform(Parent.any, "Platform this device is part of.")
+    eventCounters = Param.Int(31, "Number of supported PMU counters")
+    pmuInterrupt = Param.Int(68, "PMU GIC interrupt number")