test, arm: Add scripts to test checkpoints

Add a set of scripts to automatically test checkpointing in the
regression framework. The checkpointing tests are similar to the
switcheroo tests, but instead of switching between CPUs, they
checkpoint the system and restore from the checkpoint again. This is
done at regular intervals, typically while booting Linux.

The implementation is fairly straight forward, with the exception that
we have to work around gem5's inability to restore from a checkpoint
after a system has been instantiated. We work around this by forking
off child processes that does the actual simulation and never
instantiate a system in the parent process unless a maximum checkpoint
count is reached (in which case we just simulate the system to
completion in the parent).

Checkpoint testing is currently only enabled 32- and 64-bit ARM
systems using atomic CPUs.

Note: An unfortunate side-effect of forking is that every new process
will overwrite the stats and terminal output from the previous
process. This means that the output directory only contains data from
the last checkpoint.

3 files changed, 229 insertions, 0 deletions

diff --git a/tests/configs/checkpoint.py b/tests/configs/checkpoint.py
new file mode 100644
index 000000000..5ca3d07b7
--- /dev/null
+++ b/tests/configs/checkpoint.py
@@ -0,0 +1,133 @@
+# Copyright (c) 2015 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: Andreas Sandberg
+
+from multiprocessing import Process
+import sys
+import os
+
+import m5
+m5.util.addToPath('../configs/common')
+
+_exit_normal = (
+    "target called exit()",
+    "m5_exit instruction encountered",
+    )
+
+_exit_limit = (
+    "simulate() limit reached",
+    )
+
+_exitcode_done = 0
+_exitcode_fail = 1
+_exitcode_checkpoint = 42
+
+
+def _run_step(name, restore=None, interval=0.5):
+    """
+    Instantiate (optionally from a checkpoint if restore is set to the
+    checkpoitn name) the system and run for interval seconds of
+    simulated time. At the end of the simulation interval, create a
+    checkpoint and exit.
+
+    As this function is intended to run in its own process using the
+    multiprocessing framework, the exit is a true call to exit which
+    terminates the process. Exit codes are used to pass information to
+    the parent.
+    """
+    if restore is not None:
+        m5.instantiate(restore)
+    else:
+        m5.instantiate()
+
+    e = m5.simulate(m5.ticks.fromSeconds(interval))
+    cause = e.getCause()
+    if cause in _exit_limit:
+        m5.checkpoint(name)
+        sys.exit(_exitcode_checkpoint)
+    elif cause in _exit_normal:
+        sys.exit(_exitcode_done)
+    else:
+        print "Test failed: Unknown exit cause: %s" % cause
+        sys.exit(_exitcode_fail)
+
+def run_test(root, interval=0.5, max_checkpoints=5):
+    """
+    Run the simulated system for a fixed amount of time and take a
+    checkpoint, then restore from the same checkpoint and run until
+    the system calls m5 exit.
+    """
+
+    cpt_name = os.path.join(m5.options.outdir, "test.cpt")
+    restore = None
+
+    for cpt_no in range(max_checkpoints):
+        # Create a checkpoint from a separate child process. This enables
+        # us to get back to a (mostly) pristine state and restart
+        # simulation from the checkpoint.
+        p = Process(target=_run_step,
+                    args=(cpt_name, ),
+                    kwargs={
+                "restore" : restore,
+                "interval" : interval,
+                })
+        p.start()
+
+        # Wait for the child to return
+        p.join()
+
+        # Restore from the checkpoint next iteration
+        restore = cpt_name
+
+        if p.exitcode == _exitcode_done:
+            print >> sys.stderr, "Test done."
+            sys.exit(0)
+        elif p.exitcode == _exitcode_checkpoint:
+            pass
+        else:
+            print >> sys.stderr, "Test failed."
+            sys.exit(1)
+
+    # Maximum number of checkpoints reached. Just run full-speed from
+    # now on.
+    m5.instantiate()
+    e = m5.simulate()
+    cause = e.getCause()
+    if cause in _exit_normal:
+        sys.exit(0)
+    else:
+        print "Test failed: Unknown exit cause: %s" % cause
+        sys.exit(1)
diff --git a/tests/configs/realview-simple-atomic-checkpoint.py b/tests/configs/realview-simple-atomic-checkpoint.py
new file mode 100644
index 000000000..784d17bbb
--- /dev/null
+++ b/tests/configs/realview-simple-atomic-checkpoint.py
@@ -0,0 +1,46 @@
+# Copyright (c) 2015 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: Andreas Sandberg
+
+from m5.objects import *
+from arm_generic import *
+import checkpoint
+
+root = LinuxArmFSSystemUniprocessor(mem_mode='atomic',
+                                    mem_class=SimpleMemory,
+                                    cpu_class=AtomicSimpleCPU).create_root()
+
+run_test = checkpoint.run_test
diff --git a/tests/configs/realview64-simple-atomic-checkpoint.py b/tests/configs/realview64-simple-atomic-checkpoint.py
new file mode 100644
index 000000000..c90f0f3d4
--- /dev/null
+++ b/tests/configs/realview64-simple-atomic-checkpoint.py
@@ -0,0 +1,50 @@
+# Copyright (c) 2015 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: Andreas Sandberg
+
+import functools
+
+from m5.objects import *
+from arm_generic import *
+import checkpoint
+
+root = LinuxArmFSSystemUniprocessor(machine_type='VExpress_EMM64',
+                                    mem_mode='atomic',
+                                    mem_class=SimpleMemory,
+                                    cpu_class=AtomicSimpleCPU).create_root()
+
+run_test = functools.partial(checkpoint.run_test, interval=1.0)
+