arm-trusted-firmware/docs/getting_started/initial-build.rst
Boyan Karatotev b50838bae7 docs(build): clarify getting started section
The Getting started section is very difficult to follow. Building the
fip comes before building the files it needs, the BL33 requirement is
given in a somewhat hand wavy way, and the Arm Developer website
download provides a lot of targets and the guide is not clear which ones
are needed on download.

Swapping the initial build and supporting tools sections makes the flow
more natural and the supporting tools section then becomes clear.
Explicitly mentioning the GCC targets avoids confusion for people less
familiar with the project (eg. new starters).

Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
Change-Id: I02e88f8c279db6d8eda68f634e8473c02b733963
2022-11-16 14:06:48 +00:00

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4.1 KiB
ReStructuredText

Performing an Initial Build
===========================
- Before building TF-A, the environment variable ``CROSS_COMPILE`` must point
to your cross compiler.
For AArch64:
.. code:: shell
export CROSS_COMPILE=<path-to-aarch64-gcc>/bin/aarch64-none-elf-
For AArch32:
.. code:: shell
export CROSS_COMPILE=<path-to-aarch32-gcc>/bin/arm-none-eabi-
It is possible to build TF-A using Clang or Arm Compiler 6. To do so
``CC`` needs to point to the clang or armclang binary, which will
also select the clang or armclang assembler. Arm Compiler 6 will be selected
when the base name of the path assigned to ``CC`` matches the string
'armclang'. GNU binutils are required since the TF-A build system doesn't
currently support Arm Scatter files. Meaning the GNU linker is used by
default for Arm Compiler 6. Because of this dependency, ``CROSS_COMPILE``
should be set as described above.
For AArch64 using Arm Compiler 6:
.. code:: shell
export CROSS_COMPILE=<path-to-aarch64-gcc>/bin/aarch64-none-elf-
make CC=<path-to-armclang>/bin/armclang PLAT=<platform> all
On the other hand, Clang uses LLVM linker (LLD) and other LLVM binutils by
default instead of GNU utilities (LLVM linker (LLD) 14.0.0 is known to
work with TF-A). ``CROSS_COMPILE`` need not be set for Clang. Please note,
that the default linker may be manually overridden using the ``LD`` variable.
Clang will be selected when the base name of the path assigned to ``CC``
contains the string 'clang'. This is to allow both clang and clang-X.Y
to work.
For AArch64 using clang:
.. code:: shell
make CC=<path-to-clang>/bin/clang PLAT=<platform> all
- Change to the root directory of the TF-A source tree and build.
For AArch64:
.. code:: shell
make PLAT=<platform> all
For AArch32:
.. code:: shell
make PLAT=<platform> ARCH=aarch32 AARCH32_SP=sp_min all
Notes:
- If ``PLAT`` is not specified, ``fvp`` is assumed by default. See the
:ref:`Build Options` document for more information on available build
options.
- (AArch32 only) Currently only ``PLAT=fvp`` is supported.
- (AArch32 only) ``AARCH32_SP`` is the AArch32 EL3 Runtime Software and it
corresponds to the BL32 image. A minimal ``AARCH32_SP``, sp_min, is
provided by TF-A to demonstrate how PSCI Library can be integrated with
an AArch32 EL3 Runtime Software. Some AArch32 EL3 Runtime Software may
include other runtime services, for example Trusted OS services. A guide
to integrate PSCI library with AArch32 EL3 Runtime Software can be found
at :ref:`PSCI Library Integration guide for Armv8-A AArch32 systems`.
- (AArch64 only) The TSP (Test Secure Payload), corresponding to the BL32
image, is not compiled in by default. Refer to the
:ref:`Test Secure Payload (TSP) and Dispatcher (TSPD)` document for
details on building the TSP.
- By default this produces a release version of the build. To produce a
debug version instead, refer to the "Debugging options" section below.
- The build process creates products in a ``build`` directory tree, building
the objects and binaries for each boot loader stage in separate
sub-directories. The following boot loader binary files are created
from the corresponding ELF files:
- ``build/<platform>/<build-type>/bl1.bin``
- ``build/<platform>/<build-type>/bl2.bin``
- ``build/<platform>/<build-type>/bl31.bin`` (AArch64 only)
- ``build/<platform>/<build-type>/bl32.bin`` (mandatory for AArch32)
where ``<platform>`` is the name of the chosen platform and ``<build-type>``
is either ``debug`` or ``release``. The actual number of images might differ
depending on the platform.
- Build products for a specific build variant can be removed using:
.. code:: shell
make DEBUG=<D> PLAT=<platform> clean
... where ``<D>`` is ``0`` or ``1``, as specified when building.
The build tree can be removed completely using:
.. code:: shell
make realclean
--------------
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