sparc: Get rid of some register type definitions.

These are IntReg, FloatReg, FloatRegBits, and MiscReg. These have been
supplanted by the global types RegVal and FloatRegVal.

Change-Id: I956abfc7b439b083403e1a0d01e0bb35020bde44
Reviewed-on: https://gem5-review.googlesource.com/c/13627
Maintainer: Gabe Black <gabeblack@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

arch,mem: Move page table construction into the arch classes.

This gets rid of an awkward NoArchPageTable class, and also gives the
arch a place to inject ISA specific parameters (specifically page size)
without having to have TheISA:: in the generic version of these types.

Change-Id: I1412f303460d5c43dafdb9b3cd07af81c908a441
Reviewed-on: https://gem5-review.googlesource.com/6981
Reviewed-by: Alexandru Duțu <alexandru.dutu@amd.com>
Maintainer: Gabe Black <gabeblack@google.com>

syscall-emul: Move memState into its own file

The Process class is full of implementation details and
structures related to SE Mode. This changeset factors out an
internal class from Process and moves it into a separate file.
The purpose behind doing this is to clean up the code and make
it a bit more modular.

Change-Id: Ic6941a1657751e8d51d5b6b1dcc04f1195884280
Reviewed-on: https://gem5-review.googlesource.com/2263
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

syscall_emul: [PATCH 15/22] add clone/execve for threading and multiprocess simulations

Modifies the clone system call and adds execve system call. Requires allowing
processes to steal thread contexts from other processes in the same system
object and the ability to detach pieces of process state (such as MemState)
to allow dynamic sharing.

syscall_emul: [patch 13/22] add system call retry capability

This changeset adds functionality that allows system calls to retry without
affecting thread context state such as the program counter or register values
for the associated thread context (when system calls return with a retry
fault).

This functionality is needed to solve problems with blocking system calls
in multi-process or multi-threaded simulations where information is passed
between processes/threads. Blocking system calls can cause deadlock because
the simulator itself is single threaded. There is only a single thread
servicing the event queue which can cause deadlock if the thread hits a
blocking system call instruction.

To illustrate the problem, consider two processes using the producer/consumer
sharing model. The processes can use file descriptors and the read and write
calls to pass information to one another. If the consumer calls the blocking
read system call before the producer has produced anything, the call will
block the event queue (while executing the system call instruction) and
deadlock the simulation.

The solution implemented in this changeset is to recognize that the system
calls will block and then generate a special retry fault. The fault will
be sent back up through the function call chain until it is exposed to the
cpu model's pipeline where the fault becomes visible. The fault will trigger
the cpu model to replay the instruction at a future tick where the call has
a chance to succeed without actually going into a blocking state.

In subsequent patches, we recognize that a syscall will block by calling a
non-blocking poll (from inside the system call implementation) and checking
for events. When events show up during the poll, it signifies that the call
would not have blocked and the syscall is allowed to proceed (calling an
underlying host system call if necessary). If no events are returned from the
poll, we generate the fault and try the instruction for the thread context
at a distant tick. Note that retrying every tick is not efficient.

As an aside, the simulator has some multi-threading support for the event
queue, but it is not used by default and needs work. Even if the event queue
was completely multi-threaded, meaning that there is a hardware thread on
the host servicing a single simulator thread contexts with a 1:1 mapping
between them, it's still possible to run into deadlock due to the event queue
barriers on quantum boundaries. The solution of replaying at a later tick
is the simplest solution and solves the problem generally.

syscall_emul: [patch 5/22] remove LiveProcess class and use Process instead

The EIOProcess class was removed recently and it was the only other class
which derived from Process. Since every Process invocation is also a
LiveProcess invocation, it makes sense to simplify the organization by
combining the fields from LiveProcess into Process.

style: [patch 3/22] reduce include dependencies in some headers

Used cppclean to help identify useless includes and removed them. This
involved erroneously included headers, but also cases where forward
declarations could have been used rather than a full include.

syscall_emul: move mmapGrowsDown() to LiveProcess

The mmapGrowsDown() method was a static method on the OperatingSystem
class (and derived classes), which worked OK for the templated syscall
emulation methods, but made it hard to access elsewhere. This patch
moves the method to be a virtual function on the LiveProcess method,
where it can be overridden for specific platforms (for now, Alpha).

This patch also changes the value of mmapGrowsDown() from being false
by default and true only on X86Linux32 to being true by default and
false only on Alpha, which seems closer to reality (though in reality
most people use ASLR and this doesn't really matter anymore).

In the process, also got rid of the unused mmap_start field on
LiveProcess and OperatingSystem mmapGrowsUp variable.

mem: adding architectural page table support for SE mode
This patch enables the use of page tables that are stored in system memory
and respect x86 specification, in SE mode. It defines an architectural
page table for x86 as a MultiLevelPageTable class and puts a placeholder
class for other ISAs page tables, giving the possibility for future
implementation.

scons: Add warning for overloaded virtual functions

A derived function with a different signature than a base class
function will result in the base class function of the same name being
hidden. The parameter list and return type for the member function in
the derived class must match those of the member function in the base
class, otherwise the function in the derived class will hide the
function in the base class and no polymorphic behaviour will occur.

This patch addresses these warnings by ensuring a unique function name
to avoid (unintentionally) hiding any functions.

includes: sort all includes

SPARC: Clean up some historical style issues.

sim: revamp unserialization procedure

Replace direct call to unserialize() on each SimObject with a pair of
calls for better control over initialization in both ckpt and non-ckpt
cases.

If restoring from a checkpoint, loadState(ckpt) is called on each
SimObject. The default implementation simply calls unserialize() if
there is a corresponding checkpoint section, so we get backward
compatibility for existing objects. However, objects can override
loadState() to get other behaviors, e.g., doing other programmed
initializations after unserialize(), or complaining if no checkpoint
section is found. (Note that the default warning for a missing
checkpoint section is now gone.)

If not restoring from a checkpoint, we call the new initState() method
on each SimObject instead. This provides a hook for state
initializations that are only required when *not* restoring from a
checkpoint.

Given this new framework, do some cleanup of LiveProcess subclasses
and X86System, which were (in some cases) emulating initState()
behavior in startup via a local flag or (in other cases) erroneously
doing initializations in startup() that clobbered state loaded earlier
by unserialize().

Syscalls: Make system calls access arguments like a stack, not an array.

When accessing arguments for a syscall, the position of an argument depends on
the policies of the ISA, how much space preceding arguments took up, and the
"alignment" of the index for this particular argument into the number of
possible storate locations. This change adjusts getSyscallArg to take its
index parameter by reference instead of value and to adjust it to point to the
possible location of the next argument on the stack, basically just after the
current one. This way, the rules for the new argument can be applied locally
without knowing about other arguments since those have already been taken into
account implicitly.

All system calls have also been changed to reflect the new interface. In a
number of cases this made the implementation clearer since it encourages
arguments to be collected in one place in order and then used as necessary
later, as opposed to scattering them throughout the function or using them in
place in long expressions. It also discourages using getSyscallArg over and
over to retrieve the same value when a temporary would do the job.

Processes: Make getting and setting system call arguments part of a process object.

This patch pulls out the auxiliary vector struct from individual ISA
LiveProcesses to the base LiveProcess definition so anyone can use them.

SPARC: Combine the 64 and 32 bit process initialization code.
Alignment is done as it was for 32 bit processes.

Make the process objects use the Params structs in their constructors, and use a limit to check if access are on the stack.

SPARC: Make software trap 3 flush the register windows like the ABI specifies.

Make trap instructions always generate TrapInstruction Fault objects which call into the Process object to handle system calls. Refactored the Process objects, and move the handler code into it's own file, and add some syscalls which are used in a natively compiled hello world. Software traps with trap number 3 (not syscall number 3) are supposed to cause the register windows to be flushed but are ignored right now. Finally, made uname for SPARC report a 2.6.12 kernel which is what m22-018.pool happens to be running.

Implement current working directory for LiveProcesses

Implemented the SPARC fill and spill handlers.

src/arch/sparc/faults.cc:
src/arch/sparc/faults.hh:
Added a function to do normal SPARC trap processing, and implemented the spill and fill faults for SE
src/arch/sparc/process.cc:
src/arch/sparc/process.hh:
Added fill and spill handlers which are stuffed into the processes address space. The location of these handlers are stored in fillStart and spillStart.

Finished changing how stat structures are translated, fixed the handling of various ids as LiveProcess parameters.

src/arch/alpha/linux/process.cc:
src/arch/alpha/linux/process.hh:
src/arch/alpha/process.cc:
src/arch/alpha/process.hh:
src/arch/alpha/tru64/process.cc:
src/arch/alpha/tru64/process.hh:
src/arch/mips/linux/process.cc:
src/arch/mips/linux/process.hh:
src/arch/mips/process.cc:
src/arch/mips/process.hh:
src/arch/sparc/linux/process.cc:
src/arch/sparc/linux/process.hh:
src/arch/sparc/process.cc:
src/arch/sparc/process.hh:
src/arch/sparc/solaris/process.cc:
src/arch/sparc/solaris/process.hh:
src/sim/process.cc:
src/sim/process.hh:
src/sim/syscall_emul.cc:
src/sim/syscall_emul.hh:
Changed Process to LiveProcess in syscall handlers and fixed the implementation of uid, euid, gid, egid, pid and ppid as LiveProcess parameters.
src/kern/tru64/tru64.hh:
Changed Process to LiveProcess in syscall handlers and fixed the implementation of uid, euid, gid, egid, pid and ppid as LiveProcess parameters. Also fit tru64 in with the new way to handle stat calls.

Move LiveProcess::create() from arch-specific files
bcak to main LiveProcess, then automatically select
ISA based on object file type. Now simulation scripts
no longer need to care about the ISA, as they can just
call LiveProcess().

configs/test/test.py:
Script no longer cares about ISA.
src/arch/alpha/process.cc:
src/arch/alpha/process.hh:
src/arch/mips/process.cc:
src/arch/mips/process.hh:
src/arch/sparc/process.cc:
src/arch/sparc/process.hh:
src/sim/process.cc:
src/sim/process.hh:
Move create() from arch-specific files back to
main LiveProcess, then automatically select ISA
based on object file type.

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.