configs: root, platform options in fs bigLITTLE

(1) Two new options are added to fs_bigLITTLE.py:
- "root": disk/partition containing the rootfs (def. "/dev/vda1")
- "machine-type": hardware platform class (def. "VExpress_GEM5_V1")
+ Accepts platform classes from PlatformConfig
(2) Default kernel is not available in public uploads, force the user
to provide its own kernel instead of crashing.

Change-Id: I88283ae12cd7289e15b9277ea2cc382e9136f11c
Reviewed-by: Ciro Santilli <ciro.santilli@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20148
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

configs, arch-arm: Check if gic has cpu_addr attribute

Add this check because Gicv3 does not have the cpu_addr attribute.

Test: Change VExpress_GEM5_V1() to VExpress_GEM5_V2() and run the
following command to boot Debian.

M5_PATH=$PWD/fs_files ./build/ARM/gem5.opt ./configs/example/arm/fs_bigLITTLE.py \
--dtb $PWD/fs_files/binaries/armv8_gem5_v2_1cpu.dtb \
--kernel $PWD/fs_files/binaries/vmlinux \
--disk $PWD/fs_files/disks/disk.img \
--cpu-type atomic --big-cpus 1 --little-cpus 0

Change-Id: I23595ae5238dc7cc915ab09300f91aa5e8c24fdc
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19648
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.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>

configs, arch-arm: Using AddrRange for Realview mem_regions

Physical memory ranges are now saved in Realview objects as pairs of
addresses (start address and size). This patch is substituting them with
a single AddrRange object.

Change-Id: I02d25d557c5c54d062f0dccef8ede45744d0ce6b
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Ciro Santilli <ciro.santilli@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/16206
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

configs: Unifiy interpretation of Realview mem_regions

In every arm platform which is making use of them, mem_regions are
interpreted as a pair of start address and size. However arm
SimpleSystem, which is using VExpress_GEM5_V1, is interpreting them as
start address and end address. This patch is fixing this mismatch.

Change-Id: I0b2a2193cd07fbc5430f233438269a9c7c353df9
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Ciro Santilli <ciro.santilli@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/16205
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

arm, config: Fix CPU names in ARM example configs

The ARM example configs used to rely on CPU aliases for the
AtomicSimpleCPU and KVM when configuring clusters. This broken when
support for CPU aliases was removed ('config: Remove support for CPU
aliases.'). This change updates the config scripts to use the full
class names instead.

Change-Id: If36c46207f39ca1897ecf77d9588f1c059819e63
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/4360
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

config: Change mem_range attribute naming in ARM SimpleSystem

MemConfig.config() expects memory ranges to be defined in a particular
way. This patch changes the naming of the mem_range attribute in
SympleSystem to enable use of MemConfig for configuring the memory.

Change-Id: I4964c136e53a99c69ff5e086cacb929aa435168d
Signed-off-by: Gabor Dozsa <gabor.dozsa@arm.com>
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/4200
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

config, arm: Add multi-core KVM support to bL config

Add support for KVM in the big.LITTLE(tm) example configuration. This
replaces the --atomic option with a --cpu-type option that can be used
to switch between atomic, kvm, and timing simulation.

When running in KVM mode, the simulation script automatically assigns
separate event queues (threads) to each of the simulated CPUs. All
simulated devices, including CPU child devices (e.g., interrupt
controllers and caches), are assigned to event queue 0.

Change-Id: Ic9a3f564db91f5a3d3cb754c5a02fdd5c17d5fdf
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
Reviewed-by: Sascha Bischoff <sascha.bischoff@arm.com>
Reviewed-by: Gabor Dozsa <gabor.dozsa@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/2561
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Weiping Liao <weipingliao@google.com>

arm, config: Add missing IOCache in bL config

This patch adds an IOCache to the example bigLITTLE
configuration. An IOCache is required for correct DMA
transfers when we have caches in the system.

Change-Id: Ifeddc1b360aacbb16b1393f361dd98873c834012
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>

mem: Split the hit_latency into tag_latency and data_latency

If the cache access mode is parallel, i.e. "sequential_access" parameter
is set to "False", tags and data are accessed in parallel. Therefore,
the hit_latency is the maximum latency between tag_latency and
data_latency. On the other hand, if the cache access mode is
sequential, i.e. "sequential_access" parameter is set to "True",
tags and data are accessed sequentially. Therefore, the hit_latency
is the sum of tag_latency plus data_latency.

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

config: Make configs/common a Python package

Continue along the same line as the recent patch that made the
Ruby-related config scripts Python packages and make also the
configs/common directory a package.

All affected config scripts are updated (hopefully).

Note that this change makes it apparent that the current organisation
and naming of the config directory and its subdirectories is rather
chaotic. We mix scripts that are directly invoked with scripts that
merely contain convenience functions. While it is not addressed in
this patch we should follow up with a re-organisation of the
config structure, and renaming of some of the packages.

arm, config: Fixups for the example big.LITTLE(tm) configuration

This patch refactors the configuration file to use a more
object-oriented design.

Change-Id: I44ac2d063c2b5901f385544fb6ce3f259459cb05
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Gabor Dozsa <gabor.dozsa@arm.com>

arm, config: Add an example ARM big.LITTLE(tm) configuration script

An ARM big.LITTLE system consists of two cpu clusters: the big
CPUs are typically complex out-of-order cores and the little
CPUs are simpler in-order ones. The fs_bigLITTLE.py script
can run a full system simulation with various number of big
and little cores and cache hierarchy. The commit also includes
two example device tree files for booting Linux on the
bigLITTLE system.

Change-Id: I6396fb3b2d8f27049ccae49d8666d643b66c088b
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>