configs: Generalize FileSystemConfig for non se.py

This patch updates the FileSystemConfig so it works with more kinds of
config scripts (e.g., the Learning gem5 scripts).

There are 4 main changes:
- Added system as a parameter to the config_filesystem function so the
function can search the system for the number of CPUs instead of relying
on options from Options.py
- Instead of calling redirect_paths everywhere config_filesystem is
used, now it is implicitly called.
- Cleaned up the Ruby scripts a bit to remove redundant calls to
config_filesystem
- Added a config_filesystem call to the Ruby Learning gem5 script
(currently the only Learning gem5 script that requires it).

In the future, I think it would be better to move the config_filesystem
call into simulate.py, probably into the instantiate function. I tried to
use the per-CPU configuration parameters instead of options from
Options.py, but that's not possible until after the SimObject params
have been finalized in instantiate.

Change-Id: Ie6501a7435cfb3ac9d2b45be3722388b34063b1e
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18848
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Tested-by: kokoro <noreply+kokoro@google.com>

configs: Fix import path error in learning_gem5 part3

Change-Id: I2c5cd22bded998bae8e7aa77e42e1b042ce1c5f5
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17869
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>

configs: Use absolute import paths

Use absoluate import paths to be Python 3 compatible. This also
imports absolute_import from __future__ to ensure that Python 2.7
behaves the same way as Python 3.

Change-Id: Ica06ed95814e9cd3e768b3e1785075e36f6e56d0
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/16708
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

learning_gem5: Add a simple config for MI_example

Adds a new config script to configure the MI_example protocol. This script
closely follows the script used for MSI, but instead supports the
MI_example protocol. This script works with the simple_ruby runscript and
can be included instead of msi_caches.

Change-Id: I8be0be67bf51369763ba103a5f101cfc01ad8859
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-on: https://gem5-review.googlesource.com/8945
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>

learning_gem5: Add config files for MSI protocol

Adds the required configuration files to run the MSI protocol. These
config files are much simpler than the current Ruby examples and follow
the pattern in the other Learning gem5 run scripts.

By default, this script runs with two CPUs and runs the recently added
thread test binary.

Currently, only SE mode is supported.

This code follows Learning gem5 Part 3.
http://learning.gem5.org/book/part3/index.html

Change-Id: I813a3153d49e47198444c38a6af30269bd1310cd
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-on: https://gem5-review.googlesource.com/8943
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>