cpu: Make get(Data|Inst)Port return a Port and not a MasterPort.

No caller uses any of the MasterPort specific properties of these
function's return values, so we can instead return a reference to the
base Port class. This makes it possible for the data and inst ports
to be of any port type, not just gem5 style MasterPorts. This makes
life simpler for, for example, systemc based CPUs which might have TLM
ports.

It also makes it possible for any two CPUs which have compatible ports
to be switched between, as long as the ports they use support being
unbound. Unfortunately that does not include TLM or systemc ports which
are bound permanently.

Change-Id: I98fce5a16d2ef1af051238e929dd96d57a4ac838
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20240
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Gabe Black <gabeblack@google.com>

cpu, dev, mem: Use the new Port methods.

Use getPeer, takeOverFrom, and << to simplify the use of ports in some
areas.

Change-Id: Idfbda27411b5d6b742f5e4927894302ea6d6a53d
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20235
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

arch, cpu, dev, gpu, mem, sim, python: start using getPort.

Replace the getMasterPort, getSlavePort, and getEthPort functions
with getPort, and remove extraneous mechanisms that are no longer
necessary.

Change-Id: Iab7e3c02d2f3a0cf33e7e824e18c28646b5bc318
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17040
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

python: Don't assume SimObjects live in the global namespace

The importer in Python 3 doesn't like the way we import SimObjects
from the global namespace. Convert the existing SimObject declarations
to import from m5.objects. As a side-effect, this makes these files
consistent with configuration files.

Change-Id: I11153502b430822130722839e1fa767b82a027aa
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/15981
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>

misc: Using smart pointers for memory Requests

This patch is changing the underlying type for RequestPtr from Request*
to shared_ptr<Request>. Having memory requests being managed by smart
pointers will simplify the code; it will also prevent memory leakage and
dangling pointers.

Change-Id: I7749af38a11ac8eb4d53d8df1252951e0890fde3
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/10996
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>

sim,cpu,mem,arch: Introduced MasterInfo data structure

With this patch a gem5 System will store more info about its Masters.
While it was previously keeping track of the Master name and Master ID
only, it is now adding a per-Master pointer to the SimObject related to
the Master.
This will make it possible for a client to query a System for a Master
using either the master's name or the master's pointer.

Change-Id: I8b97d328a65cd06f329e2cdd3679451c17d2b8f6
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/9781
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>

cpu, gpu-compute: Replace EventWrapper use with EventFunctionWrapper

Change-Id: Idd5992463bcf9154f823b82461070d1f1842cea3
Signed-off-by: Sean Wilson <spwilson2@wisc.edu>
Reviewed-on: https://gem5-review.googlesource.com/3746
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

cpu: Print progress messages in Trace CPU

This change adds the ability to print a message at intervals
of committed instruction count to indicate progress in the
trace replay.

Change-Id: I8363502354c42bfc52936d2627986598b63a5797
Reviewed-by: Rekai Gonzalez Alberquilla <rekai.gonzalezalberquilla@arm.com>
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/2321
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

cpu: Support exit when any one Trace CPU completes replay

This change adds a Trace CPU param to exit simulation early,
i.e. when the first (any one) trace execution is complete. With
this change the user gets a choice to configure exit as either
when the last CPU finishes (default) or first CPU finishes
replay. Configuring an early exit enables simulating and
measuring stats strictly when memory-system resources are being
stressed by all Trace CPUs.

Change-Id: I3998045fdcc5cd343e1ca92d18dd7f7ecdba8f1d
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>

cpu: Adjust for trace offset and fix stats

This change subtracts the time offset present in the trace from
all the event times when nodes and request are sent so that the
replay starts immediately when the simulation starts. This makes
the stats accurate when the time offset in traces is large, for
example when traces are generated in the middle of a workload
execution. It also solves the problem of unnecessary DRAM
refresh events that would keep occuring during the large time
offset before even a single request is replayed into the system.

Change-Id: Ie0898842615def867ffd5c219948386d952af7f7
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>

cpu: Add frequency scaling to the Trace CPU

This change adds a simple feature to scale the frequency of
the Trace CPU.

The compute delays in the input traces provide timing. This
change adds a freqency multiplier parameter to the Trace CPU
set to 1.0 by default. The compute delay is manipulated to
effectively achieve the frequency at which the nodes become
ready and thus scale the frequency of the Trace CPU.

Change-Id: Iaabbd57806941ad56094fcddbeb38fcee1172431
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>

mem: Remove threadId from memory request class

In general, the ThreadID parameter is unnecessary in the memory system
as the ContextID is what is used for the purposes of locks/wakeups.
Since we allocate sequential ContextIDs for each thread on MT-enabled
CPUs, ThreadID is unnecessary as the CPUs can identify the requesting
thread through sideband info (SenderState / LSQ entries) or ContextID
offset from the base ContextID for a cpu.

This is a re-spin of 20264eb after the revert (bd1c6789) and includes
some fixes of that commit.

Revert power patch sets with unexpected interactions

The following patches had unexpected interactions with the current
upstream code and have been reverted for now:

e07fd01651f3: power: Add support for power models
831c7f2f9e39: power: Low-power idle power state for idle CPUs
4f749e00b667: power: Add power states to ClockedObject

Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>

mem: Remove threadId from memory request class

In general, the ThreadID parameter is unnecessary in the memory system
as the ContextID is what is used for the purposes of locks/wakeups.
Since we allocate sequential ContextIDs for each thread on MT-enabled
CPUs, ThreadID is unnecessary as the CPUs can identify the requesting
thread through sideband info (SenderState / LSQ entries) or ContextID
offset from the base ContextID for a cpu.

scons: Enable -Wextra by default

Make best use of the compiler, and enable -Wextra as well as
-Wall. There are a few issues that had to be resolved, but they are
all trivial.

cpu: Support virtual addr in elastic traces

This patch adds support to optionally capture the virtual address and asid
for load/store instructions in the elastic traces. If they are present in
the traces, Trace CPU will set those fields of the request during replay.

cpu: Create record type enum for elastic traces

This patch replaces the booleans that specified the elastic trace record
type with an enum type. The source of change is the proto message for
elastic trace where the enum is introduced. The struct definitions in the
elastic trace probe listener as well as the Trace CPU replace the boleans
with the proto message enum.

The patch does not impact functionality, but traces are not compatible with
previous version. This is preparation for adding new types of records in
subsequent patches.

cpu: Add TraceCPU to playback elastic traces

This patch defines a TraceCPU that replays trace generated using the elastic
trace probe attached to the O3 CPU model. The elastic trace is an execution
trace with data dependencies and ordering dependencies annoted to it. It also
replays fixed timestamp instruction fetch trace that is also generated by the
elastic trace probe.

The TraceCPU inherits from BaseCPU as a result of which some methods need
to be defined. It has two port subclasses inherited from MasterPort for
instruction and data ports. It issues the memory requests deducing the
timing from the trace and without performing real execution of micro-ops.
As soon as the last dependency for an instruction is complete,
its computational delay, also provided in the input trace is added. The
dependency-free nodes are maintained in a list, called 'ReadyList',
ordered by ready time. Instructions which depend on load stall until the
responses for read requests are received thus achieving elastic replay. If
the dependency is not found when adding a new node, it is assumed complete.
Thus, if this node is found to be completely dependency-free its issue time is
calculated and it is added to the ready list immediately. This is encapsulated
in the subclass ElasticDataGen.

If ready nodes are issued in an unconstrained way there can be more nodes
outstanding which results in divergence in timing compared to the O3CPU.
Therefore, the Trace CPU also models hardware resources. A sub-class to model
hardware resources is added which contains the maximum sizes of load buffer,
store buffer and ROB. If resources are not available, the node is not issued.
The 'depFreeQueue' structure holds nodes that are pending issue.

Modeling the ROB size in the Trace CPU as a resource limitation is arguably the
most important parameter of all resources. The ROB occupancy is estimated using
the newly added field 'robNum'. We need to use ROB number as sequence number is
at times much higher due to squashing and trace replay is focused on correct
path modeling.

A map called 'inFlightNodes' is added to track nodes that are not only in
the readyList but also load nodes that are executed (and thus removed from
readyList) but are not complete. ReadyList handles what and when to execute
next node while the inFlightNodes is used for resource modelling. The oldest
ROB number is updated when any node occupies the ROB or when an entry in the
ROB is released. The ROB occupancy is equal to the difference in the ROB number
of the newly dependency-free node and the oldest ROB number in flight.

If no node dependends on a non load/store node then there is no reason to track
it in the dependency graph. We filter out such nodes but count them and add a
weight field to the subsequent node that we do include in the trace. The weight
field is used to model ROB occupancy during replay.

The depFreeQueue is chosen to be FIFO so that child nodes which are in
program order get pushed into it in that order and thus issued in the in
program order, like in the O3CPU. This is also why the dependents is made a
sequential container, std::set to std::vector. We only check head of the
depFreeQueue as nodes are issued in order and blocking on head models that
better than looping the entire queue. An alternative choice would be to inspect
top N pending nodes where N is the issue-width. This is left for future as the
timing correlation looks good as it is.

At the start of an execution event, first we attempt to issue such pending
nodes by checking if appropriate resources have become available. If yes, we
compute the execute tick with respect to the time then. Then we proceed to
complete nodes from the readyList.

When a read response is received, sometimes a dependency on it that was
supposed to be released when it was issued is still not released. This occurs
because the dependent gets added to the graph after the read was sent. So the
check is made less strict and the dependency is marked complete on read
response instead of insisting that it should have been removed on read sent.

There is a check for requests spanning two cache lines as this condition
triggers an assert fail in the L1 cache. If it does then truncate the size
to access only until the end of that line and ignore the remainder.
Strictly-ordered requests are skipped and the dependencies on such requests
are handled by simply marking them complete immediately.

The simulated seconds can be calculated as the difference between the
final_tick stat and the tickOffset stat. A CountedExitEvent that contains
a static int belonging to the Trace CPU class as a down counter is used to
implement multi Trace CPU simulation exit.

cpu: Prune the stale TraceCPU

This patch prunes the TraceCPU as the code is stale and the
functionality that it provided can now be achieved with the TrafficGen
using its trace playback mode.

The TraceCPU was able to play back pre-recorded memory traces of a few
different formats, and to achieve this level of flexibility with the
TrafficGen, use the util/encode_packet_trace (with suitable
modifications) to create a protobuf trace off-line.

includes: sort all includes

Replace curTick global variable with accessor functions.
This step makes it easy to replace the accessor functions
(which still access a global variable) with ones that access
per-thread curTick values.

request: rename INST_READ to INST_FETCH.

Make the Event::description() a const function

Rename cycles() function to ticks()

Merge python and x86 changes with cache branch

Event descriptions should not end in "event"
(they function as adjectives not nouns)

Merge with head.

Major changes to how SimObjects are created and initialized. Almost all
creation and initialization now happens in python. Parameter objects
are generated and initialized by python. The .ini file is now solely for
debugging purposes and is not used in construction of the objects in any
way.

Rework the way SCons recurses into subdirectories, making it
automatic. The point is that now a subdirectory can be added
to the build process just by creating a SConscript file in it.
The process has two passes. On the first pass, all subdirs
of the root of the tree are searched for SConsopts files.
These files contain any command line options that ought to be
added for a particular subdirectory. On the second pass,
all subdirs of the src directory are searched for SConscript
files. These files describe how to build any given subdirectory.
I have added a Source() function. Any file (relative to the
directory in which the SConscript resides) passed to that
function is added to the build. Clean up everything to take
advantage of Source().
function is added to the list of files to be built.

Move main control from C++ into Python.
User script now invokes initialization and
simulation loop after building configuration.
These functions are exported from C++ to Python
using SWIG.

SConstruct:
Set up SWIG builder & scanner.
Set up symlinking of source files into build directory
(by not disabling the default behavior).
configs/test/test.py:
Rewrite to use new script-driven interface.
Include a sample option.
src/SConscript:
Set up symlinking of source files into build directory
(by not disabling the default behavior).
Add SWIG-generated main_wrap.cc to source list.
src/arch/SConscript:
Set up symlinking of source files into build directory
(by not disabling the default behavior).
src/arch/alpha/ev5.cc:
src/arch/alpha/isa/decoder.isa:
src/cpu/o3/alpha_cpu_impl.hh:
src/cpu/trace/opt_cpu.cc:
src/cpu/trace/trace_cpu.cc:
src/sim/pseudo_inst.cc:
src/sim/root.cc:
src/sim/serialize.cc:
src/sim/syscall_emul.cc:
SimExit() is now exitSimLoop().
src/cpu/base.cc:
SimExitEvent is now SimLoopExitEvent
src/python/SConscript:
Add SWIG build command for main.i.
Use python/m5 in build dir as source for zip archive...
easy now with file duplication enabled.
src/python/m5/__init__.py:
- Move copyright notice back to C++ so we can print
it right away, even for interactive sessions.
- Get rid of argument parsing code; just provide default
option descriptors for user script to call optparse with.
- Don't clutter m5 namespace by sucking in all of m5.config
and m5.objects.
- Move instantiate() function here from config.py.
src/python/m5/config.py:
- Move instantiate() function to __init__.py.
- Param.Foo deferred type lookups must use m5.objects
namespace now (not m5).
src/python/m5/objects/AlphaConsole.py:
src/python/m5/objects/AlphaFullCPU.py:
src/python/m5/objects/AlphaTLB.py:
src/python/m5/objects/BadDevice.py:
src/python/m5/objects/BaseCPU.py:
src/python/m5/objects/BaseCache.py:
src/python/m5/objects/Bridge.py:
src/python/m5/objects/Bus.py:
src/python/m5/objects/CoherenceProtocol.py:
src/python/m5/objects/Device.py:
src/python/m5/objects/DiskImage.py:
src/python/m5/objects/Ethernet.py:
src/python/m5/objects/Ide.py:
src/python/m5/objects/IntrControl.py:
src/python/m5/objects/MemObject.py:
src/python/m5/objects/MemTest.py:
src/python/m5/objects/Pci.py:
src/python/m5/objects/PhysicalMemory.py:
src/python/m5/objects/Platform.py:
src/python/m5/objects/Process.py:
src/python/m5/objects/Repl.py:
src/python/m5/objects/Root.py:
src/python/m5/objects/SimConsole.py:
src/python/m5/objects/SimpleDisk.py:
src/python/m5/objects/System.py:
src/python/m5/objects/Tsunami.py:
src/python/m5/objects/Uart.py:
Fix up imports (m5 namespace no longer includes m5.config).
src/sim/eventq.cc:
src/sim/eventq.hh:
Support for Python-called simulate() function:
- Use IsExitEvent flag to signal events that want
to exit the simulation loop gracefully (instead of
calling exit() to terminate the process).
- Modify interface to hand exit event object back to
caller so it can be inspected for cause.
src/sim/host.hh:
Add MaxTick constant.
src/sim/main.cc:
Move copyright notice back to C++ so we can print
it right away, even for interactive sessions.
Use PYTHONPATH environment var to set module path
(instead of clunky code injection method).
Move main control from here into Python:
- Separate initialization code and simulation loop
into separate functions callable from Python.
- Make Python interpreter invocation more pure (more
like directly invoking interpreter).
Add -i and -p flags (only options on binary itself;
other options processed by Python).
Import readline package when using interactive mode.
src/sim/sim_events.cc:
SimExitEvent is now SimLoopExitEvent, and uses
IsSimExit flag to terminate loop (instead of
exiting simulator process).
src/sim/sim_events.hh:
SimExitEvent is now SimLoopExitEvent, and uses
IsSimExit flag to terminate loop (instead of
exiting simulator process).
Get rid of a few unused constructors.
src/sim/sim_exit.hh:
SimExit() is now exitSimLoop().
Get rid of unused functions.
Add comments.

Updated Authors from bk prs info

New directory structure:
- simulator source now in 'src' subdirectory
- imported files from 'ext' repository
- support building in arbitrary places, including
outside of the source tree. See comment at top
of SConstruct file for more details.
Regression tests are temporarily disabled; that
syetem needs more extensive revisions.

SConstruct:
Update for new directory structure.
Modify to support build trees that are not subdirectories
of the source tree. See comment at top of file for
more details.
Regression tests are temporarily disabled.
src/arch/SConscript:
src/arch/isa_parser.py:
src/python/SConscript:
Update for new directory structure.