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>

config, arm: Don't import timing models for missing CPUs

When importing the cores.arm package, we currently throw an exception
if a timing model can't be imported due to a missing dependency (e.g.,
the required CPU model wasn't included in the build). This is
undesirable since it prevents other, working, timing models from being
added to the package. Wrap the import_module call in a try-except
block and skip timing models that have missing dependencies.

Change-Id: I92bab62c989f433a8a4a7bf59207d9d81b3d19e1
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/3946
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

config: Clean up core timing model discovery

Instead of hard-coding timing models in CpuConfig.py, use
introspection to find them in the cores.arm model package.

Change-Id: I6642dc9cbc3f5beeeec748e716c9426c233d51ea
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Gabor Dozsa <gabor.dozsa@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/3944
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

config: Move core timing models to config/common/cores

Change-Id: I189b6462cc64f7cc6c1b7a6c2af1abb60e1854de
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Gabor Dozsa <gabor.dozsa@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/3943
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>