systemc: Update the systemc example to use m5.systemc for sc_main.

Change-Id: I431d3f2c18964bac1a3f19eacfffd49cd6e50fa2
Reviewed-on: https://gem5-review.googlesource.com/c/16569
Maintainer: Gabe Black <gabeblack@google.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>

systemc: Allow specific functions to shadow the base class method

sc_in::bind and sc_core::sc_object::print shadow their respective base
class method. This change adds the necessary declarations to inform
the compiler that this is intentional.

Change-Id: I8c6bc0f05aa568630783db63d52be90f4ea4748c
Signed-off-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/15135
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Update the gem5-within-systemc README to mention USE_SYSTEMC.

When linking with an external systemc host, the native gem5 systemc API
should be disabled to avoid linking conflicts.

Change-Id: If7f9b3718fcdbdab5ebc9ef52e746f6bf9f2fb9c
Reviewed-on: https://gem5-review.googlesource.com/c/14520
Reviewed-by: Matthias Jung <jungma@eit.uni-kl.de>
Maintainer: Gabe Black <gabeblack@google.com>

util: Add some examples for using systemc code within gem5.

These examples have comments inside them that explain what they do.
There's also a README file which explains how to use the examples
generally, and at a high level what each one does.

Change-Id: I223963dc1c190289986b2ee5705910dbcad4a4c9
Reviewed-on: https://gem5-review.googlesource.com/c/13376
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

util: Move the existing systemc example into a subdirectory.

This example is for how to embed gem5 within systemc and make it use
the systemc event queue. This used to be the only method of using
gem5 and systemc together, but now that there are other options, it's
ambiguous to have it as the only thing in the util/systemc directory.

This change moves it into a gem5_within_systemc subdirectory which
clearly shows what type of integration that example corresponds with.

Change-Id: I426d68ccb618397d820bef492cbb1ff8ef4a979b
Reviewed-on: https://gem5-review.googlesource.com/c/13375
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

misc: Rename misc.(hh|cc) to logging.(hh|cc)

These files aren't a collection of miscellaneous stuff, they're the
definition of the Logger interface, and a few utility macros for
calling into that interface (panic, warn, etc.).

Change-Id: I84267ac3f45896a83c0ef027f8f19c5e9a5667d1
Reviewed-on: https://gem5-review.googlesource.com/6226
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Maintainer: Gabe Black <gabeblack@google.com>

misc: minor fix for the gem5-SystemC/TLM coupling.

This patch has a minor fix for the coupling between gem5 and SystemC-TLM.

It also fixes some typos in the related documentation.

Change-Id: I894568729b8ebdacc5b81c9f46e8f9d137da210f
Reviewed-on: https://gem5-review.googlesource.com/2480
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

misc: fix includes in util/systemc

This fixes compilation errors with clang on OS X.

Reviewed at http://reviews.gem5.org/r/3807/

Signed-off-by: Jason Lowe-Power <jason@lowepower.com>

misc: Implement the Base SystemC Module as an sc_channel.

Implementing the Module as an sc_channel allows derived classes to provide
SystemC interfaces. Other SystemC modules can connect to these interfaces.
This meachanism can be used to control gem5 and acces gem5 components from
within arbitrary SystemC moduels. Since sc_channel is derived from
sc_module, this patch does not break compatibility with existing code.

Signed-off-by: Jason Lowe-Power <jason@lowepower.com>

misc: Add support for switching multiple cores in SystemC

This patch adds a '-n' flag to the gem5 SystemC driver which allows
multiple CPUs to be switched out to a new CPU. Primarily this involves
appending CPU numbers to the objects searched for in the config
manager if there are multiple CPUs in the system.

Note that an equivalent change should be made to the util/cxx_config driver,
but I wanted to get input on this first before making the same change over
there

Signed-off-by: Jason Lowe-Power <jason@lowepower.com>

misc: fixes deprecated sc_time function for SystemC 2.3.1

The non-standard sc_time constructors

- sc_time( uint64, bool scale )
- sc_time( double, bool scale )

have been deprecated in SystemC 2.3.1 and a warning is issued when being
used. Insted the new 'sc_time::from_value' function is used to omit the
warning message.

Signed-off-by: Jason Lowe-Power <jason@lowepower.com>

misc: Documentation Update

Updates for READMEs of /util/cxx_config, /util/systemc, /util/tlm.
Some minor corrections, mostly with respect to MAC/OSX

Signed-off-by: Jason Lowe-Power <jason@lowepower.com>

misc: fix a compile error due to incompability with SystemC 2.3.1

This patch fixes an ambigous call compile error

Committed by Jason Lowe-Power <jason@lowepower.com>

misc: Separate stats file for SystemC-gem5 co-simulation

In previous versions of systemC-gem5 coupling statistics were not updated
for the systemc-gem5 simulation. systemC-gem5 simulation only need the
previously built config.ini file and normal gem5 simulation has to be run
once to generate config.ini file. Thus stats.txt inside the m5out folder is
redundant for systemC-gem5 simulation. A new stats file is now generated
with the all the statistics for systemC-gem5 simulation. This will also
resolve the stats issue in tlm-sysmtemC simulation.

Committed by Jason Lowe-Power <jason@lowepower.com>

util: DrainManager/Checkpoint changes in SystemC coupling

Due to changes in Drain Manager, the lastest systemc coupling doesn't work. The
code for handling Checkpoint has been modified and it is now compatiable with
new drain manager.

Testing is being done on systemC coupling. It needs more testing to verify
checkpointing feature.

Committed by: Nilay Vaish <nilay@cs.wisc.edu>

base: remove Trace::enabled flag

The DTRACE() macro tests both Trace::enabled and the specific flag. This
change uses the same administrative interface for enabling/disabling
tracing, but masks the SimpleFlags settings directly. This eliminates a
load for every DTRACE() test, e.g. DPRINTF.

misc: Bugfix for Freezing Terminal in SystemC Simulation

If the terminal was used in the SystemC or TLM simulations the simulation gets
in a deadlock state. This is because of the Event queue gets locked while
servicing the async events leading to event queue deadlock. This was solved by
locking the queue at the beginning of service of async events.

Committed by: Nilay Vaish <nilay@cs.wisc.edu>

config: Fix to SystemC example's event handling

This patch fixes checkpoint restore in the SystemC hosting example by handling
early PollEvent events correctly before any EventQueue events are posted.

The SystemC event queue handler (SCEventQueue) reports an error if the event
loop is entered with no Events posted. It is possible for this to happen
after instantiate due to PollEvent events. This patch separates out
`external' events into a different handler in sc_module.cc to prevent the
error from occurring.

This fix also improves the event handling of asynchronous events by:

1) Making asynchronous events 'catch up' gem5 time to SystemC
time to avoid the appearance that events have been lost
while servicing an asynchronous event that schedules an
event loop exit event

2) Add an in_simulate data member to Module to allow the event
loop to check whether events should be processed or deferred
until the next time Module::simulate is entered

3) Cancel pending events around the entry/exit of the event loop
in Module::simulate

4) Moving the state initialisation of the example entirely into
run to correct a problem with early events in checkpoint
restore.

It is still possible to schedule asynchronous events (and talk PollQueue
actions) while simulate is not running. This behaviour may stil cause
some problems.

config: SystemC Gem5Control top level additions

This patch cleans up a few style issues and adds a few capabilities to the
SystemC top level 'Gem5Control/Gem5System' mechanism. These include:

1) A space to store/retrieve a version string for a model
2) A mechanism for registering functions to be called at the end of
elaboration to perform simulation setup tasks in SystemC
3) Adding setGDBRemotePort to the Gem5Control
4) Changing the sc_set_time_resolution behaviour to instead check that
the SystemC time resolution is already acceptable

sim: SystemC hosting

This patch hosts gem5 onto SystemC scheduler. There's already an upstream
review board patch that does something similar but this patch ...:

1) is less obtrusive to the existing gem5 code organisation. It's divided
into the 'generic' preparatory patches (already submitted) and this patch
which affects no existing files

2) does not try to exactly track the gem5 event queue with notifys into
SystemC and so doesn't requive the event queue to be modified for
anything other than 'out of event queue' scheduling events

3) supports debug logging with SC_REPORT

The patch consists of the files:
util/systemc/
sc_gem5_control.{cc,hh} -- top level objects to use to
instantiate gem5 Systems within
larger SystemC test harnesses as
sc_module objects
sc_logger.{cc,hh} -- logging support
sc_module.{cc,hh} -- a separated event loop specific to
SystemC
stats.{cc,hh} -- example Stats handling for the sample
top level
main.{cc,hh} -- a sample top level

On the downside this patch is only currently functional with C++
configuration at the top level.

The above sc_... files are indended to be compiled alongside gem5 (as a
library, see main.cc for a command line and util/systemc/README for
more details.)

The top-level system instantiation in sc_gem5_control.{cc,hh} provides
two classes: Gem5Control and Gem5System

Gem5Control is a simulation control class (from which a singleton
object should be created) derived from Gem5SystemC::Module which
carries the top level simulation control interface for gem5. This
includes hosting a system-building configuration file and
instantiating the Root object from that file.

Gem5System is a base class for instantiating renamed gem5 Systems
from the config file hosted by the Gem5Control object. In use, a
SystemC module class should be made which represents the desired,
instantiable gem5 System. That class's instances should create
a Gem5System during their construction, set the parameters of that
system and then call instantiate to build that system. If this
is all carried out in the sc_core::sc_module-derived classes
constructor, the System's external ports will become children of
that module and can then be recovered by name using sc_core::
sc_find_object.

It is intended that this interface is used with dlopen. To that
end, the header file sc_gem5_control.hh includes no other header
files from gem5 (and so can be easily copied into another project).
The classes Gem5System and Gem5Control have all their member
functions declared `virtual' so that those functions can be called
through the vtable acquired by building the top level Gem5Control
using dlsym(..., "makeGem5Control") and `makeSystem' on the
Gem5Control.