stats: Move the swpipl function into the Alpha kernel stats.

This stat is only incremented by Alpha. Also move the _hwrei into the Alpha
stats object since it's the class that actually sets up and maintains that
value and it probably should have been there all along.

Change-Id: Ibd038a33230c01432c160490926d8e1e55f8ccb0
Reviewed-on: https://gem5-review.googlesource.com/4601
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

stats: Get rid of some kernel stats related cruft.

The kernel stat mechanism should really be refactored and moved somewhere
else, but in the mean time there's some old cruft that can be cleared away.

Change-Id: I21e725de590dda0d20bf3bc675bbe976c7b1bd86
Reviewed-on: https://gem5-review.googlesource.com/4600
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

style: [patch 1/22] use /r/3648/ to reorganize includes

alpha: Remove ALPHA tru64 support and associated tests

No one appears to be using it, and it is causing build issues
and increases the development and maintenance effort.

sim: Refactor the serialization base class

Objects that are can be serialized are supposed to inherit from the
Serializable class. This class is meant to provide a unified API for
such objects. However, so far it has mainly been used by SimObjects
due to some fundamental design limitations. This changeset redesigns
to the serialization interface to make it more generic and hide the
underlying checkpoint storage. Specifically:

* Add a set of APIs to serialize into a subsection of the current
object. Previously, objects that needed this functionality would
use ad-hoc solutions using nameOut() and section name
generation. In the new world, an object that implements the
interface has the methods serializeSection() and
unserializeSection() that serialize into a named /subsection/ of
the current object. Calling serialize() serializes an object into
the current section.

* Move the name() method from Serializable to SimObject as it is no
longer needed for serialization. The fully qualified section name
is generated by the main serialization code on the fly as objects
serialize sub-objects.

* Add a scoped ScopedCheckpointSection helper class. Some objects
need to serialize data structures, that are not deriving from
Serializable, into subsections. Previously, this was done using
nameOut() and manual section name generation. To simplify this,
this changeset introduces a ScopedCheckpointSection() helper
class. When this class is instantiated, it adds a new /subsection/
and subsequent serialization calls during the lifetime of this
helper class happen inside this section (or a subsection in case
of nested sections).

* The serialize() call is now const which prevents accidental state
manipulation during serialization. Objects that rely on modifying
state can use the serializeOld() call instead. The default
implementation simply calls serialize(). Note: The old-style calls
need to be explicitly called using the
serializeOld()/serializeSectionOld() style APIs. These are used by
default when serializing SimObjects.

* Both the input and output checkpoints now use their own named
types. This hides underlying checkpoint implementation from
objects that need checkpointing and makes it easier to change the
underlying checkpoint storage code.

ISA: generic Linux thread info support

This patch takes the Linux thread info support scattered across
different ISA implementations (currently in ARM, ALPHA, and MIPS), and
unifies them into a single file.

Adds a few more helper functions to read out TGID, mm, etc.

ISA-specific information (e.g., ALPHA PCBB register) is now moved to
the corresponding isa_traits.hh files.

trace: reimplement the DTRACE function so it doesn't use a vector
At the same time, rename the trace flags to debug flags since they
have broader usage than simply tracing. This means that
--trace-flags is now --debug-flags and --trace-help is now --debug-help

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.

alpha: Clean up namespace usage.

Linux Support: Finally update vptr for new memory system.

*MiscReg->*MiscRegNoEffect, *MiscRegWithEffect->*MiscReg

Put kernel_stats back into arch.