sim-se: const for loader's loadSection param

The port proxy can be declared as a reference to a const proxy
rather than just a reference to a proxy.

Change-Id: I4640b0c5f33e2334c1e7630131f78607ced40a34
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/12301
Maintainer: Brandon Potter <Brandon.Potter@amd.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>

style: Correct some style issues

This changeset fixes line alignment issues, spacing, spelling,
etc. for files that are used during SE Mode.

Change-Id: Ie61b8d0eb4ebb5af554d72f1297808027833616e
Reviewed-on: https://gem5-review.googlesource.com/2264
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Tony Gutierrez <anthony.gutierrez@amd.com>
Reviewed-by: Michael LeBeane <Michael.Lebeane@amd.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Pierre-Yves Péneau <pierre-yves.peneau@lirmm.fr>

base: add symbol support for dynamic libraries

Libraries are loaded into the process address space using the
mmap system call. Conveniently, this happens to be a good
time to update the process symbol table with the library's
incoming symbols so we handle the table update from within the
system call.

This works just like an application's normal symbols. The only
difference between a dynamic library and a main executable is
when the symbol table update occurs. The symbol table update for
an executable happens at program load time and is finished before
the process ever begins executing. Since dynamic linking happens
at runtime, the symbol loading happens after the library is
first loaded into the process address space. The library binary
is examined at this time for a symbol section and that section
is parsed for symbol types with specific bindings (global,
local, weak). Subsequently, these symbols are added to the table
and are available for use by gem5 for things like trace
generation.

Checkpointing should work just as it did previously. The address
space (and therefore the library) will be recorded and the symbol
table will be entirely recorded. (It's not possible to do anything
clever like checkpoint a program and then load the program back
with different libraries with LD_LIBRARY_PATH, because the
library becomes part of the address space after being loaded.)

base: support dynamic loading of Linux ELF objects in SE mode

base: remove fd from object loaders

All the object loaders directly examine the (already completely loaded
by object_file.cc) memory image. There is no current motivation to
keep the fd around.

arm: Add support for ARMv8 (AArch64 & AArch32)

Note: AArch64 and AArch32 interworking is not supported. If you use an AArch64
kernel you are restricted to AArch64 user-mode binaries. This will be addressed
in a later patch.

Note: Virtualization is only supported in AArch32 mode. This will also be fixed
in a later patch.

Contributors:
Giacomo Gabrielli (TrustZone, LPAE, system-level AArch64, AArch64 NEON, validation)
Thomas Grocutt (AArch32 Virtualization, AArch64 FP, validation)
Mbou Eyole (AArch64 NEON, validation)
Ali Saidi (AArch64 Linux support, code integration, validation)
Edmund Grimley-Evans (AArch64 FP)
William Wang (AArch64 Linux support)
Rene De Jong (AArch64 Linux support, performance opt.)
Matt Horsnell (AArch64 MP, validation)
Matt Evans (device models, code integration, validation)
Chris Adeniyi-Jones (AArch64 syscall-emulation)
Prakash Ramrakhyani (validation)
Dam Sunwoo (validation)
Chander Sudanthi (validation)
Stephan Diestelhorst (validation)
Andreas Hansson (code integration, performance opt.)
Eric Van Hensbergen (performance opt.)
Gabe Black

base: load weak symbols from object file
Without loading weak symbols into gem5, some function names and the given PC
cannot correspond correctly, because the binding attributes of unction names
in an ELF file are not only STB_GLOBAL or STB_LOCAL, but also STB_WEAK. This
patch adds a function for loading weak symbols.

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

MEM: Make port proxies use references rather than pointers

This patch is adding a clearer design intent to all objects that would
not be complete without a port proxy by making the proxies members
rathen than dynamically allocated. In essence, if NULL would not be a
valid value for the proxy, then we avoid using a pointer to make this
clear.

The same approach is used for the methods using these proxies, such as
loadSections, that now use references rather than pointers to better
reflect the fact that NULL would not be an acceptable value (in fact
the code would break and that is how this patch started out).

Overall the concept of "using a reference to express unconditional
composition where a NULL pointer is never valid" could be done on a
much broader scale throughout the code base, but for now it is only
done in the locations affected by the proxies.

MEM: Add port proxies instead of non-structural ports

Port proxies are used to replace non-structural ports, and thus enable
all ports in the system to correspond to a structural entity. This has
the advantage of accessing memory through the normal memory subsystem
and thus allowing any constellation of distributed memories, address
maps, etc. Most accesses are done through the "system port" that is
used for loading binaries, debugging etc. For the entities that belong
to the CPU, e.g. threads and thread contexts, they wrap the CPU data
port in a port proxy.

The following replacements are made:
FunctionalPort > PortProxy
TranslatingPort > SETranslatingPortProxy
VirtualPort > FSTranslatingPortProxy

includes: sort all includes

Loader: Use address mask provided to load*Symbols when loading the symbols from the symbol table.

Loader: Load all segments of an elf, rather than just the "text" and "data".

Loader: Error if a TLS section is found in the binary.

check if an executable is dynamic and die if it is
Only implemented for ELf. Someone might want to implement it for ecoff and some point

src/base/loader/elf_object.cc:
src/base/loader/elf_object.hh:
src/base/loader/object_file.cc:
src/base/loader/object_file.hh:
add a function to check if an executable is dynamic
src/sim/process.cc:
check if an executable is dynamic and die if it is

Load the hypervisor symbols twice, once with an address mask so that we can get symbols for where it's copied to in memory
Add the ability to use an address mask for symbol loading
Rather then silently failing on platform accesses panic
Move BadAddr/IsaFake no Device from Tsunami
Let the system kernel be none, but warn about it

configs/common/FSConfig.py:
We don't have a kernel for sparc yet
src/arch/sparc/system.cc:
Load the hypervisor symbols twice, once with an address mask so that we can get symbols for where it's copied to in memory
src/base/loader/aout_object.cc:
src/base/loader/aout_object.hh:
src/base/loader/ecoff_object.cc:
src/base/loader/ecoff_object.hh:
src/base/loader/elf_object.cc:
src/base/loader/elf_object.hh:
src/base/loader/object_file.hh:
src/base/loader/raw_object.cc:
src/base/loader/raw_object.hh:
Add the ability to use an address mask for symbol loading
src/dev/sparc/t1000.cc:
Rather then silently failing on platform accesses panic
src/dev/sparc/t1000.hh:
fix up a couple of platform comments
src/python/m5/objects/Bus.py:
src/python/m5/objects/Device.py:
src/python/m5/objects/T1000.py:
src/python/m5/objects/Tsunami.py:
Move BadAddr/IsaFake no Device from Tsunami
src/python/m5/objects/System.py:
Let kernel be none
src/sim/system.cc:
Let the system kernel be none, but warn about it

Added code to support setting up all of the auxillieary vectors configured by the sparc linux elf loader.

src/arch/sparc/process.cc:
All of the auxilliary vectors are now set like they are in the linux elf loader. This code should probably be moved to arch/sparc/linux/process.cc somehow.

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.