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Translation regimes that only support one virtual address space (such as
the ones for EL2 and EL3) can flag memory regions as execute-never by
setting to 1 the XN bit in the Upper Attributes field in the translation
tables descriptors. Translation regimes that support two different
virtual address spaces (such as the one shared by EL1 and EL0) use bits
PXN and UXN instead.

The Trusted Firmware runs at EL3 and EL1, it has to handle translation
tables of both translation regimes, but the previous code handled both
regimes the same way, as if both had only 1 VA range.

When trying to set a descriptor as execute-never it would set the XN
bit correctly in EL3, but it would set the XN bit in EL1 as well. XN is
at the same bit position as UXN, which means that EL0 was being
prevented from executing code at this region, not EL1 as the code
intended. Therefore, the PXN bit was unset to 0 all the time. The result
is that, in AArch64 mode, read-only data sections of BL2 weren't
protected from being executed.

This patch adds support of translation regimes with two virtual address
spaces to both versions of the translation tables library, fixing the
execute-never permissions for translation tables in EL1.

The library currently does not support initializing translation tables
for EL0 software, therefore it does not set/unset the UXN bit. If EL1
software needs to initialize translation tables for EL0 software, it
should use a different library instead.

Change-Id: If27588f9820ff42988851d90dc92801c8ecbe0c9
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

This patch modifies both versions of the translation table library
to use the mmap_attr_t type consistently wherever it is manipulating
MT_* attributes variables. It used to use mmap_attr_t or plain integer
types interchangeably, which compiles fine because an enumeration type
can be silently converted to an integer, but which is semantically
incorrect.

This patch removes this assumption by using the abstract type
'mmap_attr_t' all the time.

Change-Id: Id1f099025d2cb962b275bb7e39ad2c4dbb4e366c
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>

Added APIs to add and remove regions to the translation tables
dynamically while the MMU is enabled. Only static regions are allowed
to overlap other static ones (for backwards compatibility).

A new private attribute (MT_DYNAMIC / MT_STATIC) has been added to
flag each region as such.

The dynamic mapping functionality can be enabled or disabled when
compiling by setting the build option PLAT_XLAT_TABLES_DYNAMIC to 1
or 0. This can be done per-image.

TLB maintenance code during dynamic table mapping and unmapping has
also been added.

Fixes ARM-software/tf-issues#310

Change-Id: I19e8992005c4292297a382824394490c5387aa3b
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@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>