When the MMU is enabled and the translation tables are mapped, data
read/writes to the translation tables are made using the attributes
specified in the translation tables themselves. However, the MMU
performs table walks with the attributes specified in TCR_ELx. They are
completely independent, so special care has to be taken to make sure
that they are the same.

This has to be done manually because it is not practical to have a test
in the code. Such a test would need to know the virtual memory region
that contains the translation tables and check that for all of the
tables the attributes match the ones in TCR_ELx. As the tables may not
even be mapped at all, this isn't a test that can be made generic.

The flags used by enable_mmu_xxx() have been moved to the same header
where the functions are.

Also, some comments in the linker scripts related to the translation
tables have been fixed.

Change-Id: I1754768bffdae75f53561b1c4a5baf043b45a304
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

To make software license auditing simpler, use SPDX[0] license
identifiers instead of duplicating the license text in every file.

NOTE: Files that have been imported by FreeBSD have not been modified.

[0]: https://spdx.org/

Change-Id: I80a00e1f641b8cc075ca5a95b10607ed9ed8761a
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>

The folder lib/xlat_tables_v2 has been created to store a new version
of the translation tables library for further modifications in patches
to follow. At the moment it only contains a basic implementation that
supports static regions.

This library allows different translation tables to be modified by
using different 'contexts'. For now, the implementation defaults to
the translation tables used by the current image, but it is possible
to modify other tables than the ones in use.

Added a new API to print debug information for the current state of
the translation tables, rather than printing the information while
the tables are being created. This allows subsequent debug printing
of the xlat tables after they have been changed, which will be useful
when dynamic regions are implemented in a patch to follow.

The common definitions stored in `xlat_tables.h` header have been moved
to a new file common to both versions, `xlat_tables_defs.h`.

All headers related to the translation tables library have been moved to
a the subfolder `xlat_tables`.

Change-Id: Ia55962c33e0b781831d43a548e505206dffc5ea9
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>