arm-trusted-firmware/docs/user-guide.rst


								Trusted Firmware-A User Guide

								=============================


								.. section-numbering::

								    :suffix: .


								.. contents::


								This document describes how to build Trusted Firmware-A (TF-A) and run it with a

								tested set of other software components using defined configurations on the Juno

								Arm development platform and Arm Fixed Virtual Platform (FVP) models. It is

								possible to use other software components, configurations and platforms but that

								is outside the scope of this document.


								This document assumes that the reader has previous experience running a fully

								bootable Linux software stack on Juno or FVP using the prebuilt binaries and

								filesystems provided by `Linaro`_. Further information may be found in the

								`Linaro instructions`_. It also assumes that the user understands the role of

								the different software components required to boot a Linux system:


								-  Specific firmware images required by the platform (e.g. SCP firmware on Juno)

								-  Normal world bootloader (e.g. UEFI or U-Boot)

								-  Device tree

								-  Linux kernel image

								-  Root filesystem


								This document also assumes that the user is familiar with the `FVP models`_ and

								the different command line options available to launch the model.


								This document should be used in conjunction with the `Firmware Design`_.


								Host machine requirements

								-------------------------


								The minimum recommended machine specification for building the software and

								running the FVP models is a dual-core processor running at 2GHz with 12GB of

								RAM. For best performance, use a machine with a quad-core processor running at

								2.6GHz with 16GB of RAM.


								The software has been tested on Ubuntu 16.04 LTS (64-bit). Packages used for

								building the software were installed from that distribution unless otherwise

								specified.


								The software has also been built on Windows 7 Enterprise SP1, using CMD.EXE,

								Cygwin, and Msys (MinGW) shells, using version 5.3.1 of the GNU toolchain.


								Tools

								-----


								Install the required packages to build TF-A with the following command:


								::


								    sudo apt-get install device-tree-compiler build-essential gcc make git libssl-dev


								TF-A has been tested with Linaro Release 18.04.


								Download and install the AArch32 or AArch64 little-endian GCC cross compiler.

								The `Linaro Release Notes`_ documents which version of the compiler to use for a

								given Linaro Release. Also, these `Linaro instructions`_ provide further

								guidance and a script, which can be used to download Linaro deliverables

								automatically.


								Optionally, TF-A can be built using clang version 4.0 or newer or Arm

								Compiler 6. See instructions below on how to switch the default compiler.


								In addition, the following optional packages and tools may be needed:


								-  ``device-tree-compiler`` (dtc) package if you need to rebuild the Flattened Device

								   Tree (FDT) source files (``.dts`` files) provided with this software. The

								   version of dtc must be 1.4.6 or above.


								-  For debugging, Arm `Development Studio 5 (DS-5)`_.


								-  To create and modify the diagram files included in the documentation, `Dia`_.

								   This tool can be found in most Linux distributions. Inkscape is needed to

								   generate the actual \*.png files.


								Getting the TF-A source code

								----------------------------


								Download the TF-A source code from Github:


								::


								    git clone https://github.com/ARM-software/arm-trusted-firmware.git


								Building TF-A

								-------------


								-  Before building TF-A, the environment variable ``CROSS_COMPILE`` must point

								   to the Linaro cross compiler.


								   For AArch64:


								   ::


								       export CROSS_COMPILE=<path-to-aarch64-gcc>/bin/aarch64-linux-gnu-


								   For AArch32:


								   ::


								       export CROSS_COMPILE=<path-to-aarch32-gcc>/bin/arm-linux-gnueabihf-


								   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. Be aware that the

								   GNU linker is used by default.  In case of being needed the linker

								   can be overriden using the ``LD`` variable. Clang linker version 6 is

								   known to work with TF-A.


								   In both cases ``CROSS_COMPILE`` should be set as described above.


								   Arm Compiler 6 will be selected when the base name of the path assigned

								   to ``CC`` matches the string 'armclang'.


								   For AArch64 using Arm Compiler 6:


								   ::


								       export CROSS_COMPILE=<path-to-aarch64-gcc>/bin/aarch64-linux-gnu-

								       make CC=<path-to-armclang>/bin/armclang PLAT=<platform> all


								   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:


								   ::


								       export CROSS_COMPILE=<path-to-aarch64-gcc>/bin/aarch64-linux-gnu-

								       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:


								   ::


								       make PLAT=<platform> all


								   For AArch32:


								   ::


								       make PLAT=<platform> ARCH=aarch32 AARCH32_SP=sp_min all


								   Notes:


								   -  If ``PLAT`` is not specified, ``fvp`` is assumed by default. See the

								      `Summary of build options`_ 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

								      `here`_.


								   -  (AArch64 only) The TSP (Test Secure Payload), corresponding to the BL32

								      image, is not compiled in by default. Refer to the

								      `Building the Test Secure Payload`_ section below.


								   -  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:


								   ::


								       make DEBUG=<D> PLAT=<platform> clean


								   ... where ``<D>`` is ``0`` or ``1``, as specified when building.


								   The build tree can be removed completely using:


								   ::


								       make realclean


								Summary of build options

								~~~~~~~~~~~~~~~~~~~~~~~~


								The TF-A build system supports the following build options. Unless mentioned

								otherwise, these options are expected to be specified at the build command

								line and are not to be modified in any component makefiles. Note that the

								build system doesn't track dependency for build options. Therefore, if any of

								the build options are changed from a previous build, a clean build must be

								performed.


								Common build options

								^^^^^^^^^^^^^^^^^^^^


								-  ``AARCH32_INSTRUCTION_SET``: Choose the AArch32 instruction set that the

								   compiler should use. Valid values are T32 and A32. It defaults to T32 due to

								   code having a smaller resulting size.


								-  ``AARCH32_SP`` : Choose the AArch32 Secure Payload component to be built as

								   as the BL32 image when ``ARCH=aarch32``. The value should be the path to the

								   directory containing the SP source, relative to the ``bl32/``; the directory

								   is expected to contain a makefile called ``<aarch32_sp-value>.mk``.


								-  ``ARCH`` : Choose the target build architecture for TF-A. It can take either

								   ``aarch64`` or ``aarch32`` as values. By default, it is defined to

								   ``aarch64``.


								-  ``ARM_ARCH_MAJOR``: The major version of Arm Architecture to target when

								   compiling TF-A. Its value must be numeric, and defaults to 8 . See also,

								   *Armv8 Architecture Extensions* and *Armv7 Architecture Extensions* in

								   `Firmware Design`_.


								-  ``ARM_ARCH_MINOR``: The minor version of Arm Architecture to target when

								   compiling TF-A. Its value must be a numeric, and defaults to 0. See also,

								   *Armv8 Architecture Extensions* in `Firmware Design`_.


								-  ``ARM_PLAT_MT``: This flag determines whether the Arm platform layer has to

								   cater for the multi-threading ``MT`` bit when accessing MPIDR. When this flag

								   is set, the functions which deal with MPIDR assume that the ``MT`` bit in

								   MPIDR is set and access the bit-fields in MPIDR accordingly. Default value of

								   this flag is 0. Note that this option is not used on FVP platforms.


								-  ``BL2``: This is an optional build option which specifies the path to BL2

								   image for the ``fip`` target. In this case, the BL2 in the TF-A will not be

								   built.


								-  ``BL2U``: This is an optional build option which specifies the path to

								   BL2U image. In this case, the BL2U in TF-A will not be built.


								-  ``BL2_AT_EL3``: This is an optional build option that enables the use of

								   BL2 at EL3 execution level.


								-  ``BL2_IN_XIP_MEM``: In some use-cases BL2 will be stored in eXecute In Place

								   (XIP) memory, like BL1. In these use-cases, it is necessary to initialize

								   the RW sections in RAM, while leaving the RO sections in place. This option

								   enable this use-case. For now, this option is only supported when BL2_AT_EL3

								   is set to '1'.


								-  ``BL31``: This is an optional build option which specifies the path to

								   BL31 image for the ``fip`` target. In this case, the BL31 in TF-A will not

								   be built.


								-  ``BL31_KEY``: This option is used when ``GENERATE_COT=1``. It specifies the

								   file that contains the BL31 private key in PEM format. If ``SAVE_KEYS=1``,

								   this file name will be used to save the key.


								-  ``BL32``: This is an optional build option which specifies the path to

								   BL32 image for the ``fip`` target. In this case, the BL32 in TF-A will not

								   be built.


								-  ``BL32_EXTRA1``: This is an optional build option which specifies the path to

								   Trusted OS Extra1 image for the  ``fip`` target.


								-  ``BL32_EXTRA2``: This is an optional build option which specifies the path to

								   Trusted OS Extra2 image for the ``fip`` target.


								-  ``BL32_KEY``: This option is used when ``GENERATE_COT=1``. It specifies the

								   file that contains the BL32 private key in PEM format. If ``SAVE_KEYS=1``,

								   this file name will be used to save the key.


								-  ``BL33``: Path to BL33 image in the host file system. This is mandatory for

								   ``fip`` target in case TF-A BL2 is used.


								-  ``BL33_KEY``: This option is used when ``GENERATE_COT=1``. It specifies the

								   file that contains the BL33 private key in PEM format. If ``SAVE_KEYS=1``,

								   this file name will be used to save the key.


								-  ``BUILD_MESSAGE_TIMESTAMP``: String used to identify the time and date of the

								   compilation of each build. It must be set to a C string (including quotes

								   where applicable). Defaults to a string that contains the time and date of

								   the compilation.


								-  ``BUILD_STRING``: Input string for VERSION\_STRING, which allows the TF-A

								   build to be uniquely identified. Defaults to the current git commit id.


								-  ``CFLAGS``: Extra user options appended on the compiler's command line in

								   addition to the options set by the build system.


								-  ``COLD_BOOT_SINGLE_CPU``: This option indicates whether the platform may

								   release several CPUs out of reset. It can take either 0 (several CPUs may be

								   brought up) or 1 (only one CPU will ever be brought up during cold reset).

								   Default is 0. If the platform always brings up a single CPU, there is no

								   need to distinguish between primary and secondary CPUs and the boot path can

								   be optimised. The ``plat_is_my_cpu_primary()`` and

								   ``plat_secondary_cold_boot_setup()`` platform porting interfaces do not need

								   to be implemented in this case.


								-  ``CRASH_REPORTING``: A non-zero value enables a console dump of processor

								   register state when an unexpected exception occurs during execution of

								   BL31. This option defaults to the value of ``DEBUG`` - i.e. by default

								   this is only enabled for a debug build of the firmware.


								-  ``CREATE_KEYS``: This option is used when ``GENERATE_COT=1``. It tells the

								   certificate generation tool to create new keys in case no valid keys are

								   present or specified. Allowed options are '0' or '1'. Default is '1'.


								-  ``CTX_INCLUDE_AARCH32_REGS`` : Boolean option that, when set to 1, will cause

								   the AArch32 system registers to be included when saving and restoring the

								   CPU context. The option must be set to 0 for AArch64-only platforms (that

								   is on hardware that does not implement AArch32, or at least not at EL1 and

								   higher ELs). Default value is 1.


								-  ``CTX_INCLUDE_FPREGS``: Boolean option that, when set to 1, will cause the FP

								   registers to be included when saving and restoring the CPU context. Default

								   is 0.


								-  ``DEBUG``: Chooses between a debug and release build. It can take either 0

								   (release) or 1 (debug) as values. 0 is the default.


								-  ``DYN_DISABLE_AUTH``: Provides the capability to dynamically disable Trusted

								   Board Boot authentication at runtime. This option is meant to be enabled only

								   for development platforms. ``TRUSTED_BOARD_BOOT`` flag must be set if this

								   flag has to be enabled. 0 is the default.


								-  ``EL3_PAYLOAD_BASE``: This option enables booting an EL3 payload instead of

								   the normal boot flow. It must specify the entry point address of the EL3

								   payload. Please refer to the "Booting an EL3 payload" section for more

								   details.


								-  ``ENABLE_AMU``: Boolean option to enable Activity Monitor Unit extensions.

								   This is an optional architectural feature available on v8.4 onwards. Some

								   v8.2 implementations also implement an AMU and this option can be used to

								   enable this feature on those systems as well. Default is 0.


								-  ``ENABLE_ASSERTIONS``: This option controls whether or not calls to ``assert()``

								   are compiled out. For debug builds, this option defaults to 1, and calls to

								   ``assert()`` are left in place. For release builds, this option defaults to 0

								   and calls to ``assert()`` function are compiled out. This option can be set

								   independently of ``DEBUG``. It can also be used to hide any auxiliary code

								   that is only required for the assertion and does not fit in the assertion

								   itself.


								-  ``ENABLE_BACKTRACE``: This option controls whether to enables backtrace

								   dumps or not. It is supported in both AArch64 and AArch32. However, in

								   AArch32 the format of the frame records are not defined in the AAPCS and they

								   are defined by the implementation. This implementation of backtrace only

								   supports the format used by GCC when T32 interworking is disabled. For this

								   reason enabling this option in AArch32 will force the compiler to only

								   generate A32 code. This option is enabled by default only in AArch64 debug

								   builds, but this behaviour can be overriden in each platform's Makefile or in

								   the build command line.


								-  ``ENABLE_MPAM_FOR_LOWER_ELS``: Boolean option to enable lower ELs to use MPAM

								   feature. MPAM is an optional Armv8.4 extension that enables various memory

								   system components and resources to define partitions; software running at

								   various ELs can assign themselves to desired partition to control their

								   performance aspects.


								   When this option is set to ``1``, EL3 allows lower ELs to access their own

								   MPAM registers without trapping into EL3. This option doesn't make use of

								   partitioning in EL3, however. Platform initialisation code should configure

								   and use partitions in EL3 as required. This option defaults to ``0``.


								-  ``ENABLE_PIE``: Boolean option to enable Position Independent Executable(PIE)

								   support within generic code in TF-A. This option is currently only supported

								   in BL31. Default is 0.


								-  ``ENABLE_PMF``: Boolean option to enable support for optional Performance

								   Measurement Framework(PMF). Default is 0.


								-  ``ENABLE_PSCI_STAT``: Boolean option to enable support for optional PSCI

								   functions ``PSCI_STAT_RESIDENCY`` and ``PSCI_STAT_COUNT``. Default is 0.

								   In the absence of an alternate stat collection backend, ``ENABLE_PMF`` must

								   be enabled. If ``ENABLE_PMF`` is set, the residency statistics are tracked in

								   software.


								-  ``ENABLE_RUNTIME_INSTRUMENTATION``: Boolean option to enable runtime

								   instrumentation which injects timestamp collection points into TF-A to

								   allow runtime performance to be measured. Currently, only PSCI is

								   instrumented. Enabling this option enables the ``ENABLE_PMF`` build option

								   as well. Default is 0.


								-  ``ENABLE_SPE_FOR_LOWER_ELS`` : Boolean option to enable Statistical Profiling

								   extensions. This is an optional architectural feature for AArch64.

								   The default is 1 but is automatically disabled when the target architecture

								   is AArch32.


								-  ``ENABLE_SPM`` : Boolean option to enable the Secure Partition Manager (SPM).

								   Refer to the `Secure Partition Manager Design guide`_ for more details about

								   this feature. Default is 0.


								-  ``ENABLE_SVE_FOR_NS``: Boolean option to enable Scalable Vector Extension

								   (SVE) for the Non-secure world only. SVE is an optional architectural feature

								   for AArch64. Note that when SVE is enabled for the Non-secure world, access

								   to SIMD and floating-point functionality from the Secure world is disabled.

								   This is to avoid corruption of the Non-secure world data in the Z-registers

								   which are aliased by the SIMD and FP registers. The build option is not

								   compatible with the ``CTX_INCLUDE_FPREGS`` build option, and will raise an

								   assert on platforms where SVE is implemented and ``ENABLE_SVE_FOR_NS`` set to

								   1. The default is 1 but is automatically disabled when the target

								   architecture is AArch32.


								-  ``ENABLE_STACK_PROTECTOR``: String option to enable the stack protection

								   checks in GCC. Allowed values are "all", "strong" and "0" (default).

								   "strong" is the recommended stack protection level if this feature is

								   desired. 0 disables the stack protection. For all values other than 0, the

								   ``plat_get_stack_protector_canary()`` platform hook needs to be implemented.

								   The value is passed as the last component of the option

								   ``-fstack-protector-$ENABLE_STACK_PROTECTOR``.


								-  ``ERROR_DEPRECATED``: This option decides whether to treat the usage of

								   deprecated platform APIs, helper functions or drivers within Trusted

								   Firmware as error. It can take the value 1 (flag the use of deprecated

								   APIs as error) or 0. The default is 0.


								-  ``EL3_EXCEPTION_HANDLING``: When set to ``1``, enable handling of exceptions

								   targeted at EL3. When set ``0`` (default), no exceptions are expected or

								   handled at EL3, and a panic will result. This is supported only for AArch64

								   builds.


								-  ``FAULT_INJECTION_SUPPORT``: ARMv8.4 externsions introduced support for fault

								   injection from lower ELs, and this build option enables lower ELs to use

								   Error Records accessed via System Registers to inject faults. This is

								   applicable only to AArch64 builds.


								   This feature is intended for testing purposes only, and is advisable to keep

								   disabled for production images.


								-  ``FIP_NAME``: This is an optional build option which specifies the FIP

								   filename for the ``fip`` target. Default is ``fip.bin``.


								-  ``FWU_FIP_NAME``: This is an optional build option which specifies the FWU

								   FIP filename for the ``fwu_fip`` target. Default is ``fwu_fip.bin``.


								-  ``GENERATE_COT``: Boolean flag used to build and execute the ``cert_create``

								   tool to create certificates as per the Chain of Trust described in

								   `Trusted Board Boot`_. The build system then calls ``fiptool`` to

								   include the certificates in the FIP and FWU\_FIP. Default value is '0'.


								   Specify both ``TRUSTED_BOARD_BOOT=1`` and ``GENERATE_COT=1`` to include support

								   for the Trusted Board Boot feature in the BL1 and BL2 images, to generate

								   the corresponding certificates, and to include those certificates in the

								   FIP and FWU\_FIP.


								   Note that if ``TRUSTED_BOARD_BOOT=0`` and ``GENERATE_COT=1``, the BL1 and BL2

								   images will not include support for Trusted Board Boot. The FIP will still

								   include the corresponding certificates. This FIP can be used to verify the

								   Chain of Trust on the host machine through other mechanisms.


								   Note that if ``TRUSTED_BOARD_BOOT=1`` and ``GENERATE_COT=0``, the BL1 and BL2

								   images will include support for Trusted Board Boot, but the FIP and FWU\_FIP

								   will not include the corresponding certificates, causing a boot failure.


								-  ``GICV2_G0_FOR_EL3``: Unlike GICv3, the GICv2 architecture doesn't have

								   inherent support for specific EL3 type interrupts. Setting this build option

								   to ``1`` assumes GICv2 *Group 0* interrupts are expected to target EL3, both

								   by `platform abstraction layer`__ and `Interrupt Management Framework`__.

								   This allows GICv2 platforms to enable features requiring EL3 interrupt type.

								   This also means that all GICv2 Group 0 interrupts are delivered to EL3, and

								   the Secure Payload interrupts needs to be synchronously handed over to Secure

								   EL1 for handling. The default value of this option is ``0``, which means the

								   Group 0 interrupts are assumed to be handled by Secure EL1.


								   .. __: `platform-interrupt-controller-API.rst`

								   .. __: `interrupt-framework-design.rst`


								-  ``HANDLE_EA_EL3_FIRST``: When set to ``1``, External Aborts and SError

								   Interrupts will be always trapped in EL3 i.e. in BL31 at runtime. When set to

								   ``0`` (default), these exceptions will be trapped in the current exception

								   level (or in EL1 if the current exception level is EL0).


								-  ``HW_ASSISTED_COHERENCY``: On most Arm systems to-date, platform-specific

								   software operations are required for CPUs to enter and exit coherency.

								   However, there exists newer systems where CPUs' entry to and exit from

								   coherency is managed in hardware. Such systems require software to only

								   initiate the operations, and the rest is managed in hardware, minimizing

								   active software management. In such systems, this boolean option enables

								   TF-A to carry out build and run-time optimizations during boot and power

								   management operations. This option defaults to 0 and if it is enabled,

								   then it implies ``WARMBOOT_ENABLE_DCACHE_EARLY`` is also enabled.


								   Note that, when ``HW_ASSISTED_COHERENCY`` is enabled, version 2 of

								   translation library (xlat tables v2) must be used; version 1 of translation

								   library is not supported.


								-  ``JUNO_AARCH32_EL3_RUNTIME``: This build flag enables you to execute EL3

								   runtime software in AArch32 mode, which is required to run AArch32 on Juno.

								   By default this flag is set to '0'. Enabling this flag builds BL1 and BL2 in

								   AArch64 and facilitates the loading of ``SP_MIN`` and BL33 as AArch32 executable

								   images.


								-  ``KEY_ALG``: This build flag enables the user to select the algorithm to be

								   used for generating the PKCS keys and subsequent signing of the certificate.

								   It accepts 3 values viz. ``rsa``, ``rsa_1_5``, ``ecdsa``. The ``rsa_1_5`` is

								   the legacy PKCS#1 RSA 1.5 algorithm which is not TBBR compliant and is

								   retained only for compatibility. The default value of this flag is ``rsa``

								   which is the TBBR compliant PKCS#1 RSA 2.1 scheme.


								-  ``HASH_ALG``: This build flag enables the user to select the secure hash

								   algorithm. It accepts 3 values viz. ``sha256``, ``sha384``, ``sha512``.

								   The default value of this flag is ``sha256``.


								-  ``LDFLAGS``: Extra user options appended to the linkers' command line in

								   addition to the one set by the build system.


								-  ``LOG_LEVEL``: Chooses the log level, which controls the amount of console log

								   output compiled into the build. This should be one of the following:


								   ::


								       0  (LOG_LEVEL_NONE)

								       10 (LOG_LEVEL_ERROR)

								       20 (LOG_LEVEL_NOTICE)

								       30 (LOG_LEVEL_WARNING)

								       40 (LOG_LEVEL_INFO)

								       50 (LOG_LEVEL_VERBOSE)


								   All log output up to and including the selected log level is compiled into

								   the build. The default value is 40 in debug builds and 20 in release builds.


								-  ``NON_TRUSTED_WORLD_KEY``: This option is used when ``GENERATE_COT=1``. It

								   specifies the file that contains the Non-Trusted World private key in PEM

								   format. If ``SAVE_KEYS=1``, this file name will be used to save the key.


								-  ``NS_BL2U``: Path to NS\_BL2U image in the host file system. This image is

								   optional. It is only needed if the platform makefile specifies that it

								   is required in order to build the ``fwu_fip`` target.


								-  ``NS_TIMER_SWITCH``: Enable save and restore for non-secure timer register

								   contents upon world switch. It can take either 0 (don't save and restore) or

								   1 (do save and restore). 0 is the default. An SPD may set this to 1 if it

								   wants the timer registers to be saved and restored.


								-  ``PL011_GENERIC_UART``: Boolean option to indicate the PL011 driver that

								   the underlying hardware is not a full PL011 UART but a minimally compliant

								   generic UART, which is a subset of the PL011. The driver will not access

								   any register that is not part of the SBSA generic UART specification.

								   Default value is 0 (a full PL011 compliant UART is present).


								-  ``PLAT``: Choose a platform to build TF-A for. The chosen platform name

								   must be subdirectory of any depth under ``plat/``, and must contain a

								   platform makefile named ``platform.mk``. For example, to build TF-A for the

								   Arm Juno board, select PLAT=juno.


								-  ``PRELOADED_BL33_BASE``: This option enables booting a preloaded BL33 image

								   instead of the normal boot flow. When defined, it must specify the entry

								   point address for the preloaded BL33 image. This option is incompatible with

								   ``EL3_PAYLOAD_BASE``. If both are defined, ``EL3_PAYLOAD_BASE`` has priority

								   over ``PRELOADED_BL33_BASE``.


								-  ``PROGRAMMABLE_RESET_ADDRESS``: This option indicates whether the reset

								   vector address can be programmed or is fixed on the platform. It can take

								   either 0 (fixed) or 1 (programmable). Default is 0. If the platform has a

								   programmable reset address, it is expected that a CPU will start executing

								   code directly at the right address, both on a cold and warm reset. In this

								   case, there is no need to identify the entrypoint on boot and the boot path

								   can be optimised. The ``plat_get_my_entrypoint()`` platform porting interface

								   does not need to be implemented in this case.


								-  ``PSCI_EXTENDED_STATE_ID``: As per PSCI1.0 Specification, there are 2 formats

								   possible for the PSCI power-state parameter viz original and extended

								   State-ID formats. This flag if set to 1, configures the generic PSCI layer

								   to use the extended format. The default value of this flag is 0, which

								   means by default the original power-state format is used by the PSCI

								   implementation. This flag should be specified by the platform makefile

								   and it governs the return value of PSCI\_FEATURES API for CPU\_SUSPEND

								   smc function id. When this option is enabled on Arm platforms, the

								   option ``ARM_RECOM_STATE_ID_ENC`` needs to be set to 1 as well.


								-  ``RAS_EXTENSION``: When set to ``1``, enable Armv8.2 RAS features. RAS features

								   are an optional extension for pre-Armv8.2 CPUs, but are mandatory for Armv8.2

								   or later CPUs.


								   When ``RAS_EXTENSION`` is set to ``1``, ``HANDLE_EA_EL3_FIRST`` must also be

								   set to ``1``.


								   This option is disabled by default.


								-  ``RESET_TO_BL31``: Enable BL31 entrypoint as the CPU reset vector instead

								   of the BL1 entrypoint. It can take the value 0 (CPU reset to BL1

								   entrypoint) or 1 (CPU reset to BL31 entrypoint).

								   The default value is 0.


								-  ``RESET_TO_SP_MIN``: SP\_MIN is the minimal AArch32 Secure Payload provided

								   in TF-A. This flag configures SP\_MIN entrypoint as the CPU reset vector

								   instead of the BL1 entrypoint. It can take the value 0 (CPU reset to BL1

								   entrypoint) or 1 (CPU reset to SP\_MIN entrypoint). The default value is 0.


								-  ``ROT_KEY``: This option is used when ``GENERATE_COT=1``. It specifies the

								   file that contains the ROT private key in PEM format. If ``SAVE_KEYS=1``, this

								   file name will be used to save the key.


								-  ``SAVE_KEYS``: This option is used when ``GENERATE_COT=1``. It tells the

								   certificate generation tool to save the keys used to establish the Chain of

								   Trust. Allowed options are '0' or '1'. Default is '0' (do not save).


								-  ``SCP_BL2``: Path to SCP\_BL2 image in the host file system. This image is optional.

								   If a SCP\_BL2 image is present then this option must be passed for the ``fip``

								   target.


								-  ``SCP_BL2_KEY``: This option is used when ``GENERATE_COT=1``. It specifies the

								   file that contains the SCP\_BL2 private key in PEM format. If ``SAVE_KEYS=1``,

								   this file name will be used to save the key.


								-  ``SCP_BL2U``: Path to SCP\_BL2U image in the host file system. This image is

								   optional. It is only needed if the platform makefile specifies that it

								   is required in order to build the ``fwu_fip`` target.


								-  ``SDEI_SUPPORT``: Setting this to ``1`` enables support for Software

								   Delegated Exception Interface to BL31 image. This defaults to ``0``.


								   When set to ``1``, the build option ``EL3_EXCEPTION_HANDLING`` must also be

								   set to ``1``.


								-  ``SEPARATE_CODE_AND_RODATA``: Whether code and read-only data should be

								   isolated on separate memory pages. This is a trade-off between security and

								   memory usage. See "Isolating code and read-only data on separate memory

								   pages" section in `Firmware Design`_. This flag is disabled by default and

								   affects all BL images.


								-  ``SMCCC_MAJOR_VERSION``: Numeric value that indicates the major version of

								   the SMC Calling Convention that the Trusted Firmware supports. The only two

								   allowed values are 1 and 2, and it defaults to 1. The minor version is

								   determined using this value.


								-  ``SPD``: Choose a Secure Payload Dispatcher component to be built into TF-A.

								   This build option is only valid if ``ARCH=aarch64``. The value should be

								   the path to the directory containing the SPD source, relative to

								   ``services/spd/``; the directory is expected to contain a makefile called

								   ``<spd-value>.mk``.


								-  ``SPIN_ON_BL1_EXIT``: This option introduces an infinite loop in BL1. It can

								   take either 0 (no loop) or 1 (add a loop). 0 is the default. This loop stops

								   execution in BL1 just before handing over to BL31. At this point, all

								   firmware images have been loaded in memory, and the MMU and caches are

								   turned off. Refer to the "Debugging options" section for more details.


								-  ``SP_MIN_WITH_SECURE_FIQ``: Boolean flag to indicate the SP_MIN handles

								   secure interrupts (caught through the FIQ line). Platforms can enable

								   this directive if they need to handle such interruption. When enabled,

								   the FIQ are handled in monitor mode and non secure world is not allowed

								   to mask these events. Platforms that enable FIQ handling in SP_MIN shall

								   implement the api ``sp_min_plat_fiq_handler()``. The default value is 0.


								-  ``TRUSTED_BOARD_BOOT``: Boolean flag to include support for the Trusted Board

								   Boot feature. When set to '1', BL1 and BL2 images include support to load

								   and verify the certificates and images in a FIP, and BL1 includes support

								   for the Firmware Update. The default value is '0'. Generation and inclusion

								   of certificates in the FIP and FWU\_FIP depends upon the value of the

								   ``GENERATE_COT`` option.


								   Note: This option depends on ``CREATE_KEYS`` to be enabled. If the keys

								   already exist in disk, they will be overwritten without further notice.


								-  ``TRUSTED_WORLD_KEY``: This option is used when ``GENERATE_COT=1``. It

								   specifies the file that contains the Trusted World private key in PEM

								   format. If ``SAVE_KEYS=1``, this file name will be used to save the key.


								-  ``TSP_INIT_ASYNC``: Choose BL32 initialization method as asynchronous or

								   synchronous, (see "Initializing a BL32 Image" section in

								   `Firmware Design`_). It can take the value 0 (BL32 is initialized using

								   synchronous method) or 1 (BL32 is initialized using asynchronous method).

								   Default is 0.


								-  ``TSP_NS_INTR_ASYNC_PREEMPT``: A non zero value enables the interrupt

								   routing model which routes non-secure interrupts asynchronously from TSP

								   to EL3 causing immediate preemption of TSP. The EL3 is responsible

								   for saving and restoring the TSP context in this routing model. The

								   default routing model (when the value is 0) is to route non-secure

								   interrupts to TSP allowing it to save its context and hand over

								   synchronously to EL3 via an SMC.


								   Note: when ``EL3_EXCEPTION_HANDLING`` is ``1``, ``TSP_NS_INTR_ASYNC_PREEMPT``

								   must also be set to ``1``.


								-  ``USE_COHERENT_MEM``: This flag determines whether to include the coherent

								   memory region in the BL memory map or not (see "Use of Coherent memory in

								   TF-A" section in `Firmware Design`_). It can take the value 1

								   (Coherent memory region is included) or 0 (Coherent memory region is

								   excluded). Default is 1.


								-  ``V``: Verbose build. If assigned anything other than 0, the build commands

								   are printed. Default is 0.


								-  ``VERSION_STRING``: String used in the log output for each TF-A image.

								   Defaults to a string formed by concatenating the version number, build type

								   and build string.


								-  ``WARMBOOT_ENABLE_DCACHE_EARLY`` : Boolean option to enable D-cache early on

								   the CPU after warm boot. This is applicable for platforms which do not

								   require interconnect programming to enable cache coherency (eg: single

								   cluster platforms). If this option is enabled, then warm boot path

								   enables D-caches immediately after enabling MMU. This option defaults to 0.


								Arm development platform specific build options

								^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


								-  ``ARM_BL31_IN_DRAM``: Boolean option to select loading of BL31 in TZC secured

								   DRAM. By default, BL31 is in the secure SRAM. Set this flag to 1 to load

								   BL31 in TZC secured DRAM. If TSP is present, then setting this option also

								   sets the TSP location to DRAM and ignores the ``ARM_TSP_RAM_LOCATION`` build

								   flag.


								-  ``ARM_CONFIG_CNTACR``: boolean option to unlock access to the ``CNTBase<N>``

								   frame registers by setting the ``CNTCTLBase.CNTACR<N>`` register bits. The

								   frame number ``<N>`` is defined by ``PLAT_ARM_NSTIMER_FRAME_ID``, which should

								   match the frame used by the Non-Secure image (normally the Linux kernel).

								   Default is true (access to the frame is allowed).


								-  ``ARM_DISABLE_TRUSTED_WDOG``: boolean option to disable the Trusted Watchdog.

								   By default, Arm platforms use a watchdog to trigger a system reset in case

								   an error is encountered during the boot process (for example, when an image

								   could not be loaded or authenticated). The watchdog is enabled in the early

								   platform setup hook at BL1 and disabled in the BL1 prepare exit hook. The

								   Trusted Watchdog may be disabled at build time for testing or development

								   purposes.


								-  ``ARM_LINUX_KERNEL_AS_BL33``: The Linux kernel expects registers x0-x3 to

								   have specific values at boot. This boolean option allows the Trusted Firmware

								   to have a Linux kernel image as BL33 by preparing the registers to these

								   values before jumping to BL33. This option defaults to 0 (disabled). For

								   AArch64 ``RESET_TO_BL31`` and for AArch32 ``RESET_TO_SP_MIN`` must be 1 when

								   using it. If this option is set to 1, ``ARM_PRELOADED_DTB_BASE`` must be set

								   to the location of a device tree blob (DTB) already loaded in memory. The

								   Linux Image address must be specified using the ``PRELOADED_BL33_BASE``

								   option.


								-  ``ARM_RECOM_STATE_ID_ENC``: The PSCI1.0 specification recommends an encoding

								   for the construction of composite state-ID in the power-state parameter.

								   The existing PSCI clients currently do not support this encoding of

								   State-ID yet. Hence this flag is used to configure whether to use the

								   recommended State-ID encoding or not. The default value of this flag is 0,

								   in which case the platform is configured to expect NULL in the State-ID

								   field of power-state parameter.


								-  ``ARM_ROTPK_LOCATION``: used when ``TRUSTED_BOARD_BOOT=1``. It specifies the

								   location of the ROTPK hash returned by the function ``plat_get_rotpk_info()``

								   for Arm platforms. Depending on the selected option, the proper private key

								   must be specified using the ``ROT_KEY`` option when building the Trusted

								   Firmware. This private key will be used by the certificate generation tool

								   to sign the BL2 and Trusted Key certificates. Available options for

								   ``ARM_ROTPK_LOCATION`` are:


								   -  ``regs`` : return the ROTPK hash stored in the Trusted root-key storage

								      registers. The private key corresponding to this ROTPK hash is not

								      currently available.

								   -  ``devel_rsa`` : return a development public key hash embedded in the BL1

								      and BL2 binaries. This hash has been obtained from the RSA public key

								      ``arm_rotpk_rsa.der``, located in ``plat/arm/board/common/rotpk``. To use

								      this option, ``arm_rotprivk_rsa.pem`` must be specified as ``ROT_KEY`` when

								      creating the certificates.

								   -  ``devel_ecdsa`` : return a development public key hash embedded in the BL1

								      and BL2 binaries. This hash has been obtained from the ECDSA public key

								      ``arm_rotpk_ecdsa.der``, located in ``plat/arm/board/common/rotpk``. To use

								      this option, ``arm_rotprivk_ecdsa.pem`` must be specified as ``ROT_KEY``

								      when creating the certificates.


								-  ``ARM_TSP_RAM_LOCATION``: location of the TSP binary. Options:


								   -  ``tsram`` : Trusted SRAM (default option when TBB is not enabled)

								   -  ``tdram`` : Trusted DRAM (if available)

								   -  ``dram`` : Secure region in DRAM (default option when TBB is enabled,

								      configured by the TrustZone controller)


								-  ``ARM_XLAT_TABLES_LIB_V1``: boolean option to compile TF-A with version 1

								   of the translation tables library instead of version 2. It is set to 0 by

								   default, which selects version 2.


								-  ``ARM_CRYPTOCELL_INTEG`` : bool option to enable TF-A to invoke Arm®

								   TrustZone® CryptoCell functionality for Trusted Board Boot on capable Arm

								   platforms. If this option is specified, then the path to the CryptoCell

								   SBROM library must be specified via ``CCSBROM_LIB_PATH`` flag.


								For a better understanding of these options, the Arm development platform memory

								map is explained in the `Firmware Design`_.


								Arm CSS platform specific build options

								^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


								-  ``CSS_DETECT_PRE_1_7_0_SCP``: Boolean flag to detect SCP version

								   incompatibility. Version 1.7.0 of the SCP firmware made a non-backwards

								   compatible change to the MTL protocol, used for AP/SCP communication.

								   TF-A no longer supports earlier SCP versions. If this option is set to 1

								   then TF-A will detect if an earlier version is in use. Default is 1.


								-  ``CSS_LOAD_SCP_IMAGES``: Boolean flag, which when set, adds SCP\_BL2 and

								   SCP\_BL2U to the FIP and FWU\_FIP respectively, and enables them to be loaded

								   during boot. Default is 1.


								-  ``CSS_USE_SCMI_SDS_DRIVER``: Boolean flag which selects SCMI/SDS drivers

								   instead of SCPI/BOM driver for communicating with the SCP during power

								   management operations and for SCP RAM Firmware transfer. If this option

								   is set to 1, then SCMI/SDS drivers will be used. Default is 0.


								Arm FVP platform specific build options

								^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


								-  ``FVP_CLUSTER_COUNT`` : Configures the cluster count to be used to

								   build the topology tree within TF-A. By default TF-A is configured for dual

								   cluster topology and this option can be used to override the default value.


								-  ``FVP_INTERCONNECT_DRIVER``: Selects the interconnect driver to be built. The

								   default interconnect driver depends on the value of ``FVP_CLUSTER_COUNT`` as

								   explained in the options below:


								   -  ``FVP_CCI`` : The CCI driver is selected. This is the default

								      if 0 < ``FVP_CLUSTER_COUNT`` <= 2.

								   -  ``FVP_CCN`` : The CCN driver is selected. This is the default

								      if ``FVP_CLUSTER_COUNT`` > 2.


								-  ``FVP_MAX_CPUS_PER_CLUSTER``: Sets the maximum number of CPUs implemented in

								   a single cluster.  This option defaults to 4.


								-  ``FVP_MAX_PE_PER_CPU``: Sets the maximum number of PEs implemented on any CPU

								   in the system. This option defaults to 1. Note that the build option

								   ``ARM_PLAT_MT`` doesn't have any effect on FVP platforms.


								-  ``FVP_USE_GIC_DRIVER`` : Selects the GIC driver to be built. Options:


								   -  ``FVP_GIC600`` : The GIC600 implementation of GICv3 is selected

								   -  ``FVP_GICV2`` : The GICv2 only driver is selected

								   -  ``FVP_GICV3`` : The GICv3 only driver is selected (default option)


								-  ``FVP_USE_SP804_TIMER`` : Use the SP804 timer instead of the Generic Timer

								   for functions that wait for an arbitrary time length (udelay and mdelay).

								   The default value is 0.


								-  ``FVP_HW_CONFIG_DTS`` : Specify the path to the DTS file to be compiled

								   to DTB and packaged in FIP as the HW_CONFIG. See `Firmware Design`_ for

								   details on HW_CONFIG. By default, this is initialized to a sensible DTS

								   file in ``fdts/`` folder depending on other build options. But some cases,

								   like shifted affinity format for MPIDR, cannot be detected at build time

								   and this option is needed to specify the appropriate DTS file.


								-  ``FVP_HW_CONFIG`` : Specify the path to the HW_CONFIG blob to be packaged in

								   FIP. See `Firmware Design`_ for details on HW_CONFIG. This option is

								   similar to the ``FVP_HW_CONFIG_DTS`` option, but it directly specifies the

								   HW_CONFIG blob instead of the DTS file. This option is useful to override

								   the default HW_CONFIG selected by the build system.


								ARM JUNO platform specific build options

								^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


								-  ``JUNO_TZMP1`` : Boolean option to configure Juno to be used for TrustZone

								   Media Protection (TZ-MP1). Default value of this flag is 0.


								Debugging options

								~~~~~~~~~~~~~~~~~


								To compile a debug version and make the build more verbose use


								::


								    make PLAT=<platform> DEBUG=1 V=1 all


								AArch64 GCC uses DWARF version 4 debugging symbols by default. Some tools (for

								example DS-5) might not support this and may need an older version of DWARF

								symbols to be emitted by GCC. This can be achieved by using the

								``-gdwarf-<version>`` flag, with the version being set to 2 or 3. Setting the

								version to 2 is recommended for DS-5 versions older than 5.16.


								When debugging logic problems it might also be useful to disable all compiler

								optimizations by using ``-O0``.


								NOTE: Using ``-O0`` could cause output images to be larger and base addresses

								might need to be recalculated (see the **Memory layout on Arm development

								platforms** section in the `Firmware Design`_).


								Extra debug options can be passed to the build system by setting ``CFLAGS`` or

								``LDFLAGS``:


								.. code:: makefile


								    CFLAGS='-O0 -gdwarf-2'                                     \

								    make PLAT=<platform> DEBUG=1 V=1 all


								Note that using ``-Wl,`` style compilation driver options in ``CFLAGS`` will be

								ignored as the linker is called directly.


								It is also possible to introduce an infinite loop to help in debugging the

								post-BL2 phase of TF-A. This can be done by rebuilding BL1 with the

								``SPIN_ON_BL1_EXIT=1`` build flag. Refer to the `Summary of build options`_

								section. In this case, the developer may take control of the target using a

								debugger when indicated by the console output. When using DS-5, the following

								commands can be used:


								::


								    # Stop target execution

								    interrupt


								    #

								    # Prepare your debugging environment, e.g. set breakpoints

								    #


								    # Jump over the debug loop

								    set var $AARCH64::$Core::$PC = $AARCH64::$Core::$PC + 4


								    # Resume execution

								    continue


								Building the Test Secure Payload

								~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


								The TSP is coupled with a companion runtime service in the BL31 firmware,

								called the TSPD. Therefore, if you intend to use the TSP, the BL31 image

								must be recompiled as well. For more information on SPs and SPDs, see the

								`Secure-EL1 Payloads and Dispatchers`_ section in the `Firmware Design`_.


								First clean the TF-A build directory to get rid of any previous BL31 binary.

								Then to build the TSP image use:


								::


								    make PLAT=<platform> SPD=tspd all


								An additional boot loader binary file is created in the ``build`` directory:


								::


								    build/<platform>/<build-type>/bl32.bin


								Checking source code style

								~~~~~~~~~~~~~~~~~~~~~~~~~~


								When making changes to the source for submission to the project, the source

								must be in compliance with the Linux style guide, and to assist with this check

								the project Makefile contains two targets, which both utilise the

								``checkpatch.pl`` script that ships with the Linux source tree.


								To check the entire source tree, you must first download copies of

								``checkpatch.pl``, ``spelling.txt`` and ``const_structs.checkpatch`` available

								in the `Linux master tree`_ scripts directory, then set the ``CHECKPATCH``

								environment variable to point to ``checkpatch.pl`` (with the other 2 files in

								the same directory) and build the target checkcodebase:


								::


								    make CHECKPATCH=<path-to-linux>/linux/scripts/checkpatch.pl checkcodebase


								To just check the style on the files that differ between your local branch and

								the remote master, use:


								::


								    make CHECKPATCH=<path-to-linux>/linux/scripts/checkpatch.pl checkpatch


								If you wish to check your patch against something other than the remote master,

								set the ``BASE_COMMIT`` variable to your desired branch. By default, ``BASE_COMMIT``

								is set to ``origin/master``.


								Building and using the FIP tool

								~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


								Firmware Image Package (FIP) is a packaging format used by TF-A to package

								firmware images in a single binary. The number and type of images that should

								be packed in a FIP is platform specific and may include TF-A images and other

								firmware images required by the platform. For example, most platforms require

								a BL33 image which corresponds to the normal world bootloader (e.g. UEFI or

								U-Boot).


								The TF-A build system provides the make target ``fip`` to create a FIP file

								for the specified platform using the FIP creation tool included in the TF-A

								project. Examples below show how to build a FIP file for FVP, packaging TF-A

								and BL33 images.


								For AArch64:


								::


								    make PLAT=fvp BL33=<path/to/bl33.bin> fip


								For AArch32:


								::


								    make PLAT=fvp ARCH=aarch32 AARCH32_SP=sp_min BL33=<path/to/bl33.bin> fip


								Note that AArch32 support for Normal world boot loader (BL33), like U-boot or

								UEFI, on FVP is not available upstream. Hence custom solutions are required to

								allow Linux boot on FVP. These instructions assume such a custom boot loader

								(BL33) is available.


								The resulting FIP may be found in:


								::


								    build/fvp/<build-type>/fip.bin


								For advanced operations on FIP files, it is also possible to independently build

								the tool and create or modify FIPs using this tool. To do this, follow these

								steps:


								It is recommended to remove old artifacts before building the tool:


								::


								    make -C tools/fiptool clean


								Build the tool:


								::


								    make [DEBUG=1] [V=1] fiptool


								The tool binary can be located in:


								::


								    ./tools/fiptool/fiptool


								Invoking the tool with ``--help`` will print a help message with all available

								options.


								Example 1: create a new Firmware package ``fip.bin`` that contains BL2 and BL31:


								::


								    ./tools/fiptool/fiptool create \

								        --tb-fw build/<platform>/<build-type>/bl2.bin \

								        --soc-fw build/<platform>/<build-type>/bl31.bin \

								        fip.bin


								Example 2: view the contents of an existing Firmware package:


								::


								    ./tools/fiptool/fiptool info <path-to>/fip.bin


								Example 3: update the entries of an existing Firmware package:


								::


								    # Change the BL2 from Debug to Release version

								    ./tools/fiptool/fiptool update \

								        --tb-fw build/<platform>/release/bl2.bin \

								        build/<platform>/debug/fip.bin


								Example 4: unpack all entries from an existing Firmware package:


								::


								    # Images will be unpacked to the working directory

								    ./tools/fiptool/fiptool unpack <path-to>/fip.bin


								Example 5: remove an entry from an existing Firmware package:


								::


								    ./tools/fiptool/fiptool remove \

								        --tb-fw build/<platform>/debug/fip.bin


								Note that if the destination FIP file exists, the create, update and

								remove operations will automatically overwrite it.


								The unpack operation will fail if the images already exist at the

								destination. In that case, use -f or --force to continue.


								More information about FIP can be found in the `Firmware Design`_ document.


								Building FIP images with support for Trusted Board Boot

								~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


								Trusted Board Boot primarily consists of the following two features:


								-  Image Authentication, described in `Trusted Board Boot`_, and

								-  Firmware Update, described in `Firmware Update`_


								The following steps should be followed to build FIP and (optionally) FWU\_FIP

								images with support for these features:


								#. Fulfill the dependencies of the ``mbedtls`` cryptographic and image parser

								   modules by checking out a recent version of the `mbed TLS Repository`_. It

								   is important to use a version that is compatible with TF-A and fixes any

								   known security vulnerabilities. See `mbed TLS Security Center`_ for more

								   information. The latest version of TF-A is tested with tag

								   ``mbedtls-2.12.0``.


								   The ``drivers/auth/mbedtls/mbedtls_*.mk`` files contain the list of mbed TLS

								   source files the modules depend upon.

								   ``include/drivers/auth/mbedtls/mbedtls_config.h`` contains the configuration

								   options required to build the mbed TLS sources.


								   Note that the mbed TLS library is licensed under the Apache version 2.0

								   license. Using mbed TLS source code will affect the licensing of TF-A

								   binaries that are built using this library.


								#. To build the FIP image, ensure the following command line variables are set

								   while invoking ``make`` to build TF-A:


								   -  ``MBEDTLS_DIR=<path of the directory containing mbed TLS sources>``

								   -  ``TRUSTED_BOARD_BOOT=1``

								   -  ``GENERATE_COT=1``


								   In the case of Arm platforms, the location of the ROTPK hash must also be

								   specified at build time. Two locations are currently supported (see

								   ``ARM_ROTPK_LOCATION`` build option):


								   -  ``ARM_ROTPK_LOCATION=regs``: the ROTPK hash is obtained from the Trusted

								      root-key storage registers present in the platform. On Juno, this

								      registers are read-only. On FVP Base and Cortex models, the registers

								      are read-only, but the value can be specified using the command line

								      option ``bp.trusted_key_storage.public_key`` when launching the model.

								      On both Juno and FVP models, the default value corresponds to an

								      ECDSA-SECP256R1 public key hash, whose private part is not currently

								      available.


								   -  ``ARM_ROTPK_LOCATION=devel_rsa``: use the ROTPK hash that is hardcoded

								      in the Arm platform port. The private/public RSA key pair may be

								      found in ``plat/arm/board/common/rotpk``.


								   -  ``ARM_ROTPK_LOCATION=devel_ecdsa``: use the ROTPK hash that is hardcoded

								      in the Arm platform port. The private/public ECDSA key pair may be

								      found in ``plat/arm/board/common/rotpk``.


								   Example of command line using RSA development keys:


								   ::


								       MBEDTLS_DIR=<path of the directory containing mbed TLS sources> \

								       make PLAT=<platform> TRUSTED_BOARD_BOOT=1 GENERATE_COT=1        \

								       ARM_ROTPK_LOCATION=devel_rsa                                    \

								       ROT_KEY=plat/arm/board/common/rotpk/arm_rotprivk_rsa.pem        \

								       BL33=<path-to>/<bl33_image>                                     \

								       all fip


								   The result of this build will be the bl1.bin and the fip.bin binaries. This

								   FIP will include the certificates corresponding to the Chain of Trust

								   described in the TBBR-client document. These certificates can also be found

								   in the output build directory.


								#. The optional FWU\_FIP contains any additional images to be loaded from

								   Non-Volatile storage during the `Firmware Update`_ process. To build the

								   FWU\_FIP, any FWU images required by the platform must be specified on the

								   command line. On Arm development platforms like Juno, these are:


								   -  NS\_BL2U. The AP non-secure Firmware Updater image.

								   -  SCP\_BL2U. The SCP Firmware Update Configuration image.


								   Example of Juno command line for generating both ``fwu`` and ``fwu_fip``

								   targets using RSA development:


								   ::


								       MBEDTLS_DIR=<path of the directory containing mbed TLS sources> \

								       make PLAT=juno TRUSTED_BOARD_BOOT=1 GENERATE_COT=1              \

								       ARM_ROTPK_LOCATION=devel_rsa                                    \

								       ROT_KEY=plat/arm/board/common/rotpk/arm_rotprivk_rsa.pem        \

								       BL33=<path-to>/<bl33_image>                                     \

								       SCP_BL2=<path-to>/<scp_bl2_image>                               \

								       SCP_BL2U=<path-to>/<scp_bl2u_image>                             \

								       NS_BL2U=<path-to>/<ns_bl2u_image>                               \

								       all fip fwu_fip


								   Note: The BL2U image will be built by default and added to the FWU\_FIP.

								   The user may override this by adding ``BL2U=<path-to>/<bl2u_image>``

								   to the command line above.


								   Note: Building and installing the non-secure and SCP FWU images (NS\_BL1U,

								   NS\_BL2U and SCP\_BL2U) is outside the scope of this document.


								   The result of this build will be bl1.bin, fip.bin and fwu\_fip.bin binaries.

								   Both the FIP and FWU\_FIP will include the certificates corresponding to the

								   Chain of Trust described in the TBBR-client document. These certificates

								   can also be found in the output build directory.


								Building the Certificate Generation Tool

								~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


								The ``cert_create`` tool is built as part of the TF-A build process when the

								``fip`` make target is specified and TBB is enabled (as described in the

								previous section), but it can also be built separately with the following

								command:


								::


								    make PLAT=<platform> [DEBUG=1] [V=1] certtool


								For platforms that require their own IDs in certificate files, the generic

								'cert\_create' tool can be built with the following command:


								::


								    make USE_TBBR_DEFS=0 [DEBUG=1] [V=1] certtool


								``DEBUG=1`` builds the tool in debug mode. ``V=1`` makes the build process more

								verbose. The following command should be used to obtain help about the tool:


								::


								    ./tools/cert_create/cert_create -h


								Building a FIP for Juno and FVP

								-------------------------------


								This section provides Juno and FVP specific instructions to build Trusted

								Firmware, obtain the additional required firmware, and pack it all together in

								a single FIP binary. It assumes that a `Linaro Release`_ has been installed.


								Note: Pre-built binaries for AArch32 are available from Linaro Release 16.12

								onwards. Before that release, pre-built binaries are only available for AArch64.


								Note: Follow the full instructions for one platform before switching to a

								different one. Mixing instructions for different platforms may result in

								corrupted binaries.


								Note: The uboot image downloaded by the Linaro workspace script does not always

								match the uboot image packaged as BL33 in the corresponding fip file. It is

								recommended to use the version that is packaged in the fip file using the

								instructions below.


								Note: For the FVP, the kernel FDT is packaged in FIP during build and loaded

								by the firmware at runtime. See `Obtaining the Flattened Device Trees`_

								section for more info on selecting the right FDT to use.


								#. Clean the working directory


								   ::


								       make realclean


								#. Obtain SCP\_BL2 (Juno) and BL33 (all platforms)


								   Use the fiptool to extract the SCP\_BL2 and BL33 images from the FIP

								   package included in the Linaro release:


								   ::


								       # Build the fiptool

								       make [DEBUG=1] [V=1] fiptool


								       # Unpack firmware images from Linaro FIP

								       ./tools/fiptool/fiptool unpack \

								            <path/to/linaro/release>/fip.bin


								   The unpack operation will result in a set of binary images extracted to the

								   current working directory. The SCP\_BL2 image corresponds to

								   ``scp-fw.bin`` and BL33 corresponds to ``nt-fw.bin``.


								   Note: The fiptool will complain if the images to be unpacked already

								   exist in the current directory. If that is the case, either delete those

								   files or use the ``--force`` option to overwrite.


								   Note: For AArch32, the instructions below assume that nt-fw.bin is a custom

								   Normal world boot loader that supports AArch32.


								#. Build TF-A images and create a new FIP for FVP


								   ::


								       # AArch64

								       make PLAT=fvp BL33=nt-fw.bin all fip


								       # AArch32

								       make PLAT=fvp ARCH=aarch32 AARCH32_SP=sp_min BL33=nt-fw.bin all fip


								#. Build TF-A images and create a new FIP for Juno


								   For AArch64:


								   Building for AArch64 on Juno simply requires the addition of ``SCP_BL2``

								   as a build parameter.


								   ::


								       make PLAT=juno all fip \

								       BL33=<path-to-juno-oe-uboot>/SOFTWARE/bl33-uboot.bin \

								       SCP_BL2=<path-to-juno-busybox-uboot>/SOFTWARE/scp_bl2.bin


								   For AArch32:


								   Hardware restrictions on Juno prevent cold reset into AArch32 execution mode,

								   therefore BL1 and BL2 must be compiled for AArch64, and BL32 is compiled

								   separately for AArch32.


								   -  Before building BL32, the environment variable ``CROSS_COMPILE`` must point

								      to the AArch32 Linaro cross compiler.


								      ::


								          export CROSS_COMPILE=<path-to-aarch32-gcc>/bin/arm-linux-gnueabihf-


								   -  Build BL32 in AArch32.


								      ::


								          make ARCH=aarch32 PLAT=juno AARCH32_SP=sp_min \

								          RESET_TO_SP_MIN=1 JUNO_AARCH32_EL3_RUNTIME=1 bl32


								   -  Before building BL1 and BL2, the environment variable ``CROSS_COMPILE``

								      must point to the AArch64 Linaro cross compiler.


								      ::


								          export CROSS_COMPILE=<path-to-aarch64-gcc>/bin/aarch64-linux-gnu-


								   -  The following parameters should be used to build BL1 and BL2 in AArch64

								      and point to the BL32 file.


								      ::


								          make ARCH=aarch64 PLAT=juno JUNO_AARCH32_EL3_RUNTIME=1 \

								          BL33=<path-to-juno32-oe-uboot>/SOFTWARE/bl33-uboot.bin \

								          SCP_BL2=<path-to-juno32-oe-uboot>/SOFTWARE/scp_bl2.bin \

								          BL32=<path-to-bl32>/bl32.bin all fip


								The resulting BL1 and FIP images may be found in:


								::


								    # Juno

								    ./build/juno/release/bl1.bin

								    ./build/juno/release/fip.bin


								    # FVP

								    ./build/fvp/release/bl1.bin

								    ./build/fvp/release/fip.bin


								Booting Firmware Update images

								-------------------------------------


								When Firmware Update (FWU) is enabled there are at least 2 new images

								that have to be loaded, the Non-Secure FWU ROM (NS-BL1U), and the

								FWU FIP.


								Juno

								~~~~


								The new images must be programmed in flash memory by adding

								an entry in the ``SITE1/HBI0262x/images.txt`` configuration file

								on the Juno SD card (where ``x`` depends on the revision of the Juno board).

								Refer to the `Juno Getting Started Guide`_, section 2.3 "Flash memory

								programming" for more information. User should ensure these do not

								overlap with any other entries in the file.


								::


									NOR10UPDATE: AUTO                       ;Image Update:NONE/AUTO/FORCE

									NOR10ADDRESS: 0x00400000                ;Image Flash Address [ns_bl2u_base_address]

									NOR10FILE: \SOFTWARE\fwu_fip.bin        ;Image File Name

									NOR10LOAD: 00000000                     ;Image Load Address

									NOR10ENTRY: 00000000                    ;Image Entry Point


									NOR11UPDATE: AUTO                       ;Image Update:NONE/AUTO/FORCE

									NOR11ADDRESS: 0x03EB8000                ;Image Flash Address [ns_bl1u_base_address]

									NOR11FILE: \SOFTWARE\ns_bl1u.bin        ;Image File Name

									NOR11LOAD: 00000000                     ;Image Load Address


								The address ns_bl1u_base_address is the value of NS_BL1U_BASE - 0x8000000.

								In the same way, the address ns_bl2u_base_address is the value of

								NS_BL2U_BASE - 0x8000000.


								FVP

								~~~


								The additional fip images must be loaded with:


								::


								    --data cluster0.cpu0="<path_to>/ns_bl1u.bin"@0x0beb8000	[ns_bl1u_base_address]

								    --data cluster0.cpu0="<path_to>/fwu_fip.bin"@0x08400000	[ns_bl2u_base_address]


								The address ns_bl1u_base_address is the value of NS_BL1U_BASE.

								In the same way, the address ns_bl2u_base_address is the value of

								NS_BL2U_BASE.


								EL3 payloads alternative boot flow

								----------------------------------


								On a pre-production system, the ability to execute arbitrary, bare-metal code at

								the highest exception level is required. It allows full, direct access to the

								hardware, for example to run silicon soak tests.


								Although it is possible to implement some baremetal secure firmware from

								scratch, this is a complex task on some platforms, depending on the level of

								configuration required to put the system in the expected state.


								Rather than booting a baremetal application, a possible compromise is to boot

								``EL3 payloads`` through TF-A instead. This is implemented as an alternative

								boot flow, where a modified BL2 boots an EL3 payload, instead of loading the

								other BL images and passing control to BL31. It reduces the complexity of

								developing EL3 baremetal code by:


								-  putting the system into a known architectural state;

								-  taking care of platform secure world initialization;

								-  loading the SCP\_BL2 image if required by the platform.


								When booting an EL3 payload on Arm standard platforms, the configuration of the

								TrustZone controller is simplified such that only region 0 is enabled and is

								configured to permit secure access only. This gives full access to the whole

								DRAM to the EL3 payload.


								The system is left in the same state as when entering BL31 in the default boot

								flow. In particular:


								-  Running in EL3;

								-  Current state is AArch64;

								-  Little-endian data access;

								-  All exceptions disabled;

								-  MMU disabled;

								-  Caches disabled.


								Booting an EL3 payload

								~~~~~~~~~~~~~~~~~~~~~~


								The EL3 payload image is a standalone image and is not part of the FIP. It is

								not loaded by TF-A. Therefore, there are 2 possible scenarios:


								-  The EL3 payload may reside in non-volatile memory (NVM) and execute in

								   place. In this case, booting it is just a matter of specifying the right

								   address in NVM through ``EL3_PAYLOAD_BASE`` when building TF-A.


								-  The EL3 payload needs to be loaded in volatile memory (e.g. DRAM) at

								   run-time.


								To help in the latter scenario, the ``SPIN_ON_BL1_EXIT=1`` build option can be

								used. The infinite loop that it introduces in BL1 stops execution at the right

								moment for a debugger to take control of the target and load the payload (for

								example, over JTAG).


								It is expected that this loading method will work in most cases, as a debugger

								connection is usually available in a pre-production system. The user is free to

								use any other platform-specific mechanism to load the EL3 payload, though.


								Booting an EL3 payload on FVP

								^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


								The EL3 payloads boot flow requires the CPU's mailbox to be cleared at reset for

								the secondary CPUs holding pen to work properly. Unfortunately, its reset value

								is undefined on the FVP platform and the FVP platform code doesn't clear it.

								Therefore, one must modify the way the model is normally invoked in order to

								clear the mailbox at start-up.


								One way to do that is to create an 8-byte file containing all zero bytes using

								the following command:


								::


								    dd if=/dev/zero of=mailbox.dat bs=1 count=8


								and pre-load it into the FVP memory at the mailbox address (i.e. ``0x04000000``)

								using the following model parameters:


								::


								    --data cluster0.cpu0=mailbox.dat@0x04000000   [Base FVPs]

								    --data=mailbox.dat@0x04000000                 [Foundation FVP]


								To provide the model with the EL3 payload image, the following methods may be

								used:


								#. If the EL3 payload is able to execute in place, it may be programmed into

								   flash memory. On Base Cortex and AEM FVPs, the following model parameter

								   loads it at the base address of the NOR FLASH1 (the NOR FLASH0 is already

								   used for the FIP):


								   ::


								       -C bp.flashloader1.fname="/path/to/el3-payload"


								   On Foundation FVP, there is no flash loader component and the EL3 payload

								   may be programmed anywhere in flash using method 3 below.


								#. When using the ``SPIN_ON_BL1_EXIT=1`` loading method, the following DS-5

								   command may be used to load the EL3 payload ELF image over JTAG:


								   ::


								       load /path/to/el3-payload.elf


								#. The EL3 payload may be pre-loaded in volatile memory using the following

								   model parameters:


								   ::


								       --data cluster0.cpu0="/path/to/el3-payload"@address  [Base FVPs]

								       --data="/path/to/el3-payload"@address                [Foundation FVP]


								   The address provided to the FVP must match the ``EL3_PAYLOAD_BASE`` address

								   used when building TF-A.


								Booting an EL3 payload on Juno

								^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


								If the EL3 payload is able to execute in place, it may be programmed in flash

								memory by adding an entry in the ``SITE1/HBI0262x/images.txt`` configuration file

								on the Juno SD card (where ``x`` depends on the revision of the Juno board).

								Refer to the `Juno Getting Started Guide`_, section 2.3 "Flash memory

								programming" for more information.


								Alternatively, the same DS-5 command mentioned in the FVP section above can

								be used to load the EL3 payload's ELF file over JTAG on Juno.


								Preloaded BL33 alternative boot flow

								------------------------------------


								Some platforms have the ability to preload BL33 into memory instead of relying

								on TF-A to load it. This may simplify packaging of the normal world code and

								improve performance in a development environment. When secure world cold boot

								is complete, TF-A simply jumps to a BL33 base address provided at build time.


								For this option to be used, the ``PRELOADED_BL33_BASE`` build option has to be

								used when compiling TF-A. For example, the following command will create a FIP

								without a BL33 and prepare to jump to a BL33 image loaded at address

								0x80000000:


								::


								    make PRELOADED_BL33_BASE=0x80000000 PLAT=fvp all fip


								Boot of a preloaded kernel image on Base FVP

								~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


								The following example uses a simplified boot flow by directly jumping from the

								TF-A to the Linux kernel, which will use a ramdisk as filesystem. This can be

								useful if both the kernel and the device tree blob (DTB) are already present in

								memory (like in FVP).


								For example, if the kernel is loaded at ``0x80080000`` and the DTB is loaded at

								address ``0x82000000``, the firmware can be built like this:


								::


								    CROSS_COMPILE=aarch64-linux-gnu-  \

								    make PLAT=fvp DEBUG=1             \

								    RESET_TO_BL31=1                   \

								    ARM_LINUX_KERNEL_AS_BL33=1        \

								    PRELOADED_BL33_BASE=0x80080000    \

								    ARM_PRELOADED_DTB_BASE=0x82000000 \

								    all fip


								Now, it is needed to modify the DTB so that the kernel knows the address of the

								ramdisk. The following script generates a patched DTB from the provided one,

								assuming that the ramdisk is loaded at address ``0x84000000``. Note that this

								script assumes that the user is using a ramdisk image prepared for U-Boot, like

								the ones provided by Linaro. If using a ramdisk without this header,the ``0x40``

								offset in ``INITRD_START`` has to be removed.


								.. code:: bash


								    #!/bin/bash


								    # Path to the input DTB

								    KERNEL_DTB=<path-to>/<fdt>

								    # Path to the output DTB

								    PATCHED_KERNEL_DTB=<path-to>/<patched-fdt>

								    # Base address of the ramdisk

								    INITRD_BASE=0x84000000

								    # Path to the ramdisk

								    INITRD=<path-to>/<ramdisk.img>


								    # Skip uboot header (64 bytes)

								    INITRD_START=$(printf "0x%x" $((${INITRD_BASE} + 0x40)) )

								    INITRD_SIZE=$(stat -Lc %s ${INITRD})

								    INITRD_END=$(printf "0x%x" $((${INITRD_BASE} + ${INITRD_SIZE})) )


								    CHOSEN_NODE=$(echo                                        \

								    "/ {                                                      \

								            chosen {                                          \

								                    linux,initrd-start = <${INITRD_START}>;   \

								                    linux,initrd-end = <${INITRD_END}>;       \

								            };                                                \

								    };")


								    echo $(dtc -O dts -I dtb ${KERNEL_DTB}) ${CHOSEN_NODE} |  \

								            dtc -O dtb -o ${PATCHED_KERNEL_DTB} -


								And the FVP binary can be run with the following command:


								::


								    <path-to>/FVP_Base_AEMv8A-AEMv8A                            \

								    -C pctl.startup=0.0.0.0                                     \

								    -C bp.secure_memory=1                                       \

								    -C cluster0.NUM_CORES=4                                     \

								    -C cluster1.NUM_CORES=4                                     \

								    -C cache_state_modelled=1                                   \

								    -C cluster0.cpu0.RVBAR=0x04020000                           \

								    -C cluster0.cpu1.RVBAR=0x04020000                           \

								    -C cluster0.cpu2.RVBAR=0x04020000                           \

								    -C cluster0.cpu3.RVBAR=0x04020000                           \

								    -C cluster1.cpu0.RVBAR=0x04020000                           \

								    -C cluster1.cpu1.RVBAR=0x04020000                           \

								    -C cluster1.cpu2.RVBAR=0x04020000                           \

								    -C cluster1.cpu3.RVBAR=0x04020000                           \

								    --data cluster0.cpu0="<path-to>/bl31.bin"@0x04020000        \

								    --data cluster0.cpu0="<path-to>/<patched-fdt>"@0x82000000   \

								    --data cluster0.cpu0="<path-to>/<kernel-binary>"@0x80080000 \

								    --data cluster0.cpu0="<path-to>/<ramdisk.img>"@0x84000000


								Boot of a preloaded kernel image on Juno

								~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


								The Trusted Firmware must be compiled in a similar way as for FVP explained

								above. The process to load binaries to memory is the one explained in

								`Booting an EL3 payload on Juno`_.


								Running the software on FVP

								---------------------------


								The latest version of the AArch64 build of TF-A has been tested on the following

								Arm FVPs without shifted affinities, and that do not support threaded CPU cores

								(64-bit host machine only).


								NOTE: Unless otherwise stated, the model version is Version 11.4 Build 37.


								-  ``FVP_Base_Aresx4``

								-  ``FVP_Base_AEMv8A-AEMv8A``

								-  ``FVP_Base_AEMv8A-AEMv8A-AEMv8A-AEMv8A-CCN502``

								-  ``FVP_Base_AEMv8A-AEMv8A``

								-  ``FVP_Base_RevC-2xAEMv8A``

								-  ``FVP_Base_Cortex-A32x4``

								-  ``FVP_Base_Cortex-A35x4``

								-  ``FVP_Base_Cortex-A53x4``

								-  ``FVP_Base_Cortex-A55x4+Cortex-A75x4``

								-  ``FVP_Base_Cortex-A55x4``

								-  ``FVP_Base_Cortex-A57x4-A53x4``

								-  ``FVP_Base_Cortex-A57x4``

								-  ``FVP_Base_Cortex-A72x4-A53x4``

								-  ``FVP_Base_Cortex-A72x4``

								-  ``FVP_Base_Cortex-A73x4-A53x4``

								-  ``FVP_Base_Cortex-A73x4``

								-  ``FVP_Base_Cortex-A75x4``

								-  ``FVP_Base_Cortex-A76x4``

								-  ``FVP_CSS_SGI-575`` (Version 11.3 build 40)

								-  ``Foundation_Platform``


								The latest version of the AArch32 build of TF-A has been tested on the following

								Arm FVPs without shifted affinities, and that do not support threaded CPU cores

								(64-bit host machine only).


								-  ``FVP_Base_AEMv8A-AEMv8A``

								-  ``FVP_Base_Cortex-A32x4``


								NOTE: The ``FVP_Base_RevC-2xAEMv8A`` FVP only supports shifted affinities, which

								is not compatible with legacy GIC configurations. Therefore this FVP does not

								support these legacy GIC configurations.


								NOTE: The build numbers quoted above are those reported by launching the FVP

								with the ``--version`` parameter.


								NOTE: Linaro provides a ramdisk image in prebuilt FVP configurations and full

								file systems that can be downloaded separately. To run an FVP with a virtio

								file system image an additional FVP configuration option

								``-C bp.virtioblockdevice.image_path="<path-to>/<file-system-image>`` can be

								used.


								NOTE: The software will not work on Version 1.0 of the Foundation FVP.

								The commands below would report an ``unhandled argument`` error in this case.


								NOTE: FVPs can be launched with ``--cadi-server`` option such that a

								CADI-compliant debugger (for example, Arm DS-5) can connect to and control its

								execution.


								NOTE: Since FVP model Version 11.0 Build 11.0.34 and Version 8.5 Build 0.8.5202

								the internal synchronisation timings changed compared to older versions of the

								models. The models can be launched with ``-Q 100`` option if they are required

								to match the run time characteristics of the older versions.


								The Foundation FVP is a cut down version of the AArch64 Base FVP. It can be

								downloaded for free from `Arm's website`_.


								The Cortex-A models listed above are also available to download from

								`Arm's website`_.


								Please refer to the FVP documentation for a detailed description of the model

								parameter options. A brief description of the important ones that affect TF-A

								and normal world software behavior is provided below.


								Obtaining the Flattened Device Trees

								~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


								Depending on the FVP configuration and Linux configuration used, different

								FDT files are required. FDT source files for the Foundation and Base FVPs can

								be found in the TF-A source directory under ``fdts/``. The Foundation FVP has

								a subset of the Base FVP components. For example, the Foundation FVP lacks

								CLCD and MMC support, and has only one CPU cluster.


								Note: It is not recommended to use the FDTs built along the kernel because not

								all FDTs are available from there.


								The dynamic configuration capability is enabled in the firmware for FVPs.

								This means that the firmware can authenticate and load the FDT if present in

								FIP. A default FDT is packaged into FIP during the build based on

								the build configuration. This can be overridden by using the ``FVP_HW_CONFIG``

								or ``FVP_HW_CONFIG_DTS`` build options (refer to the

								`Arm FVP platform specific build options`_ section for detail on the options).


								-  ``fvp-base-gicv2-psci.dts``


								   For use with models such as the Cortex-A57-A53 Base FVPs without shifted

								   affinities and with Base memory map configuration.


								-  ``fvp-base-gicv2-psci-aarch32.dts``


								   For use with models such as the Cortex-A32 Base FVPs without shifted

								   affinities and running Linux in AArch32 state with Base memory map

								   configuration.


								-  ``fvp-base-gicv3-psci.dts``


								   For use with models such as the Cortex-A57-A53 Base FVPs without shifted

								   affinities and with Base memory map configuration and Linux GICv3 support.


								-  ``fvp-base-gicv3-psci-1t.dts``


								   For use with models such as the AEMv8-RevC Base FVP with shifted affinities,

								   single threaded CPUs, Base memory map configuration and Linux GICv3 support.


								-  ``fvp-base-gicv3-psci-dynamiq.dts``


								   For use with models as the Cortex-A55-A75 Base FVPs with shifted affinities,

								   single cluster, single threaded CPUs, Base memory map configuration and Linux

								   GICv3 support.


								-  ``fvp-base-gicv3-psci-aarch32.dts``


								   For use with models such as the Cortex-A32 Base FVPs without shifted

								   affinities and running Linux in AArch32 state with Base memory map

								   configuration and Linux GICv3 support.


								-  ``fvp-foundation-gicv2-psci.dts``


								   For use with Foundation FVP with Base memory map configuration.


								-  ``fvp-foundation-gicv3-psci.dts``


								   (Default) For use with Foundation FVP with Base memory map configuration

								   and Linux GICv3 support.


								Running on the Foundation FVP with reset to BL1 entrypoint

								~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


								The following ``Foundation_Platform`` parameters should be used to boot Linux with

								4 CPUs using the AArch64 build of TF-A.


								::


								    <path-to>/Foundation_Platform                   \

								    --cores=4                                       \

								    --arm-v8.0                                      \

								    --secure-memory                                 \

								    --visualization                                 \

								    --gicv3                                         \

								    --data="<path-to>/<bl1-binary>"@0x0             \

								    --data="<path-to>/<FIP-binary>"@0x08000000      \

								    --data="<path-to>/<kernel-binary>"@0x80080000   \

								    --data="<path-to>/<ramdisk-binary>"@0x84000000


								Notes:


								-  BL1 is loaded at the start of the Trusted ROM.

								-  The Firmware Image Package is loaded at the start of NOR FLASH0.

								-  The firmware loads the FDT packaged in FIP to the DRAM. The FDT load address

								   is specified via the ``hw_config_addr`` property in `TB_FW_CONFIG for FVP`_.

								-  The default use-case for the Foundation FVP is to use the ``--gicv3`` option

								   and enable the GICv3 device in the model. Note that without this option,

								   the Foundation FVP defaults to legacy (Versatile Express) memory map which

								   is not supported by TF-A.

								-  In order for TF-A to run correctly on the Foundation FVP, the architecture

								   versions must match. The Foundation FVP defaults to the highest v8.x

								   version it supports but the default build for TF-A is for v8.0. To avoid

								   issues either start the Foundation FVP to use v8.0 architecture using the

								   ``--arm-v8.0`` option, or build TF-A with an appropriate value for

								   ``ARM_ARCH_MINOR``.


								Running on the AEMv8 Base FVP with reset to BL1 entrypoint

								~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


								The following ``FVP_Base_RevC-2xAEMv8A`` parameters should be used to boot Linux

								with 8 CPUs using the AArch64 build of TF-A.


								::


								    <path-to>/FVP_Base_RevC-2xAEMv8A                            \

								    -C pctl.startup=0.0.0.0                                     \

								    -C bp.secure_memory=1                                       \

								    -C bp.tzc_400.diagnostics=1                                 \

								    -C cluster0.NUM_CORES=4                                     \

								    -C cluster1.NUM_CORES=4                                     \

								    -C cache_state_modelled=1                                   \

								    -C bp.secureflashloader.fname="<path-to>/<bl1-binary>"      \

								    -C bp.flashloader0.fname="<path-to>/<FIP-binary>"           \

								    --data cluster0.cpu0="<path-to>/<kernel-binary>"@0x80080000 \

								    --data cluster0.cpu0="<path-to>/<ramdisk>"@0x84000000


								Running on the AEMv8 Base FVP (AArch32) with reset to BL1 entrypoint

								~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


								The following ``FVP_Base_AEMv8A-AEMv8A`` parameters should be used to boot Linux

								with 8 CPUs using the AArch32 build of TF-A.


								::


								    <path-to>/FVP_Base_AEMv8A-AEMv8A                            \

								    -C pctl.startup=0.0.0.0                                     \

								    -C bp.secure_memory=1                                       \

								    -C bp.tzc_400.diagnostics=1                                 \

								    -C cluster0.NUM_CORES=4                                     \

								    -C cluster1.NUM_CORES=4                                     \

								    -C cache_state_modelled=1                                   \

								    -C cluster0.cpu0.CONFIG64=0                                 \

								    -C cluster0.cpu1.CONFIG64=0                                 \

								    -C cluster0.cpu2.CONFIG64=0                                 \

								    -C cluster0.cpu3.CONFIG64=0                                 \

								    -C cluster1.cpu0.CONFIG64=0                                 \

								    -C cluster1.cpu1.CONFIG64=0                                 \

								    -C cluster1.cpu2.CONFIG64=0                                 \

								    -C cluster1.cpu3.CONFIG64=0                                 \

								    -C bp.secureflashloader.fname="<path-to>/<bl1-binary>"      \

								    -C bp.flashloader0.fname="<path-to>/<FIP-binary>"           \

								    --data cluster0.cpu0="<path-to>/<kernel-binary>"@0x80080000 \

								    --data cluster0.cpu0="<path-to>/<ramdisk>"@0x84000000


								Running on the Cortex-A57-A53 Base FVP with reset to BL1 entrypoint

								~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


								The following ``FVP_Base_Cortex-A57x4-A53x4`` model parameters should be used to

								boot Linux with 8 CPUs using the AArch64 build of TF-A.


								::


								    <path-to>/FVP_Base_Cortex-A57x4-A53x4                       \

								    -C pctl.startup=0.0.0.0                                     \

								    -C bp.secure_memory=1                                       \

								    -C bp.tzc_400.diagnostics=1                                 \

								    -C cache_state_modelled=1                                   \

								    -C bp.secureflashloader.fname="<path-to>/<bl1-binary>"      \

								    -C bp.flashloader0.fname="<path-to>/<FIP-binary>"           \

								    --data cluster0.cpu0="<path-to>/<kernel-binary>"@0x80080000 \

								    --data cluster0.cpu0="<path-to>/<ramdisk>"@0x84000000


								Running on the Cortex-A32 Base FVP (AArch32) with reset to BL1 entrypoint

								~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


								The following ``FVP_Base_Cortex-A32x4`` model parameters should be used to

								boot Linux with 4 CPUs using the AArch32 build of TF-A.


								::


								    <path-to>/FVP_Base_Cortex-A32x4                             \

								    -C pctl.startup=0.0.0.0                                     \

								    -C bp.secure_memory=1                                       \

								    -C bp.tzc_400.diagnostics=1                                 \

								    -C cache_state_modelled=1                                   \

								    -C bp.secureflashloader.fname="<path-to>/<bl1-binary>"      \

								    -C bp.flashloader0.fname="<path-to>/<FIP-binary>"           \

								    --data cluster0.cpu0="<path-to>/<kernel-binary>"@0x80080000 \

								    --data cluster0.cpu0="<path-to>/<ramdisk>"@0x84000000


								Running on the AEMv8 Base FVP with reset to BL31 entrypoint

								~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


								The following ``FVP_Base_RevC-2xAEMv8A`` parameters should be used to boot Linux

								with 8 CPUs using the AArch64 build of TF-A.


								::


								    <path-to>/FVP_Base_RevC-2xAEMv8A                             \

								    -C pctl.startup=0.0.0.0                                      \

								    -C bp.secure_memory=1                                        \

								    -C bp.tzc_400.diagnostics=1                                  \

								    -C cluster0.NUM_CORES=4                                      \

								    -C cluster1.NUM_CORES=4                                      \

								    -C cache_state_modelled=1                                    \

								    -C cluster0.cpu0.RVBAR=0x04010000                            \

								    -C cluster0.cpu1.RVBAR=0x04010000                            \

								    -C cluster0.cpu2.RVBAR=0x04010000                            \

								    -C cluster0.cpu3.RVBAR=0x04010000                            \

								    -C cluster1.cpu0.RVBAR=0x04010000                            \

								    -C cluster1.cpu1.RVBAR=0x04010000                            \

								    -C cluster1.cpu2.RVBAR=0x04010000                            \

								    -C cluster1.cpu3.RVBAR=0x04010000                            \

								    --data cluster0.cpu0="<path-to>/<bl31-binary>"@0x04010000    \

								    --data cluster0.cpu0="<path-to>/<bl32-binary>"@0xff000000    \

								    --data cluster0.cpu0="<path-to>/<bl33-binary>"@0x88000000    \

								    --data cluster0.cpu0="<path-to>/<fdt>"@0x82000000            \

								    --data cluster0.cpu0="<path-to>/<kernel-binary>"@0x80080000  \

								    --data cluster0.cpu0="<path-to>/<ramdisk>"@0x84000000


								Notes:


								-  Since Position Independent Executable (PIE) support is enabled for BL31

								   in this config, it can be loaded at any valid address for execution.


								-  Since a FIP is not loaded when using BL31 as reset entrypoint, the

								   ``--data="<path-to><bl31|bl32|bl33-binary>"@<base-address-of-binary>``

								   parameter is needed to load the individual bootloader images in memory.

								   BL32 image is only needed if BL31 has been built to expect a Secure-EL1

								   Payload. For the same reason, the FDT needs to be compiled from the DT source

								   and loaded via the ``--data cluster0.cpu0="<path-to>/<fdt>"@0x82000000``

								   parameter.


								-  The ``-C cluster<X>.cpu<Y>.RVBAR=@<base-address-of-bl31>`` parameter, where

								   X and Y are the cluster and CPU numbers respectively, is used to set the

								   reset vector for each core.


								-  Changing the default value of ``ARM_TSP_RAM_LOCATION`` will also require

								   changing the value of

								   ``--data="<path-to><bl32-binary>"@<base-address-of-bl32>`` to the new value of

								   ``BL32_BASE``.


								Running on the AEMv8 Base FVP (AArch32) with reset to SP\_MIN entrypoint

								~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


								The following ``FVP_Base_AEMv8A-AEMv8A`` parameters should be used to boot Linux

								with 8 CPUs using the AArch32 build of TF-A.


								::


								    <path-to>/FVP_Base_AEMv8A-AEMv8A                             \

								    -C pctl.startup=0.0.0.0                                      \

								    -C bp.secure_memory=1                                        \

								    -C bp.tzc_400.diagnostics=1                                  \

								    -C cluster0.NUM_CORES=4                                      \

								    -C cluster1.NUM_CORES=4                                      \

								    -C cache_state_modelled=1                                    \

								    -C cluster0.cpu0.CONFIG64=0                                  \

								    -C cluster0.cpu1.CONFIG64=0                                  \

								    -C cluster0.cpu2.CONFIG64=0                                  \

								    -C cluster0.cpu3.CONFIG64=0                                  \

								    -C cluster1.cpu0.CONFIG64=0                                  \

								    -C cluster1.cpu1.CONFIG64=0                                  \

								    -C cluster1.cpu2.CONFIG64=0                                  \

								    -C cluster1.cpu3.CONFIG64=0                                  \

								    -C cluster0.cpu0.RVBAR=0x04002000                            \

								    -C cluster0.cpu1.RVBAR=0x04002000                            \

								    -C cluster0.cpu2.RVBAR=0x04002000                            \

								    -C cluster0.cpu3.RVBAR=0x04002000                            \

								    -C cluster1.cpu0.RVBAR=0x04002000                            \

								    -C cluster1.cpu1.RVBAR=0x04002000                            \

								    -C cluster1.cpu2.RVBAR=0x04002000                            \

								    -C cluster1.cpu3.RVBAR=0x04002000                            \

								    --data cluster0.cpu0="<path-to>/<bl32-binary>"@0x04002000    \

								    --data cluster0.cpu0="<path-to>/<bl33-binary>"@0x88000000    \

								    --data cluster0.cpu0="<path-to>/<fdt>"@0x82000000            \

								    --data cluster0.cpu0="<path-to>/<kernel-binary>"@0x80080000  \

								    --data cluster0.cpu0="<path-to>/<ramdisk>"@0x84000000


								Note: The load address of ``<bl32-binary>`` depends on the value ``BL32_BASE``.

								It should match the address programmed into the RVBAR register as well.


								Running on the Cortex-A57-A53 Base FVP with reset to BL31 entrypoint

								~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


								The following ``FVP_Base_Cortex-A57x4-A53x4`` model parameters should be used to

								boot Linux with 8 CPUs using the AArch64 build of TF-A.


								::


								    <path-to>/FVP_Base_Cortex-A57x4-A53x4                        \

								    -C pctl.startup=0.0.0.0                                      \

								    -C bp.secure_memory=1                                        \

								    -C bp.tzc_400.diagnostics=1                                  \

								    -C cache_state_modelled=1                                    \

								    -C cluster0.cpu0.RVBARADDR=0x04010000                        \

								    -C cluster0.cpu1.RVBARADDR=0x04010000                        \

								    -C cluster0.cpu2.RVBARADDR=0x04010000                        \

								    -C cluster0.cpu3.RVBARADDR=0x04010000                        \

								    -C cluster1.cpu0.RVBARADDR=0x04010000                        \

								    -C cluster1.cpu1.RVBARADDR=0x04010000                        \

								    -C cluster1.cpu2.RVBARADDR=0x04010000                        \

								    -C cluster1.cpu3.RVBARADDR=0x04010000                        \

								    --data cluster0.cpu0="<path-to>/<bl31-binary>"@0x04010000    \

								    --data cluster0.cpu0="<path-to>/<bl32-binary>"@0xff000000    \

								    --data cluster0.cpu0="<path-to>/<bl33-binary>"@0x88000000    \

								    --data cluster0.cpu0="<path-to>/<fdt>"@0x82000000            \

								    --data cluster0.cpu0="<path-to>/<kernel-binary>"@0x80080000  \

								    --data cluster0.cpu0="<path-to>/<ramdisk>"@0x84000000


								Running on the Cortex-A32 Base FVP (AArch32) with reset to SP\_MIN entrypoint

								~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


								The following ``FVP_Base_Cortex-A32x4`` model parameters should be used to

								boot Linux with 4 CPUs using the AArch32 build of TF-A.


								::


								    <path-to>/FVP_Base_Cortex-A32x4                             \

								    -C pctl.startup=0.0.0.0                                     \

								    -C bp.secure_memory=1                                       \

								    -C bp.tzc_400.diagnostics=1                                 \

								    -C cache_state_modelled=1                                   \

								    -C cluster0.cpu0.RVBARADDR=0x04002000                       \

								    -C cluster0.cpu1.RVBARADDR=0x04002000                       \

								    -C cluster0.cpu2.RVBARADDR=0x04002000                       \

								    -C cluster0.cpu3.RVBARADDR=0x04002000                       \

								    --data cluster0.cpu0="<path-to>/<bl32-binary>"@0x04002000   \

								    --data cluster0.cpu0="<path-to>/<bl33-binary>"@0x88000000   \

								    --data cluster0.cpu0="<path-to>/<fdt>"@0x82000000           \

								    --data cluster0.cpu0="<path-to>/<kernel-binary>"@0x80080000 \

								    --data cluster0.cpu0="<path-to>/<ramdisk>"@0x84000000


								Running the software on Juno

								----------------------------


								This version of TF-A has been tested on variants r0, r1 and r2 of Juno.


								To execute the software stack on Juno, the version of the Juno board recovery

								image indicated in the `Linaro Release Notes`_ must be installed. If you have an

								earlier version installed or are unsure which version is installed, please

								re-install the recovery image by following the

								`Instructions for using Linaro's deliverables on Juno`_.


								Preparing TF-A images

								~~~~~~~~~~~~~~~~~~~~~


								After building TF-A, the files ``bl1.bin`` and ``fip.bin`` need copying to the

								``SOFTWARE/`` directory of the Juno SD card.


								Other Juno software information

								~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


								Please visit the `Arm Platforms Portal`_ to get support and obtain any other Juno

								software information. Please also refer to the `Juno Getting Started Guide`_ to

								get more detailed information about the Juno Arm development platform and how to

								configure it.


								Testing SYSTEM SUSPEND on Juno

								~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


								The SYSTEM SUSPEND is a PSCI API which can be used to implement system suspend

								to RAM. For more details refer to section 5.16 of `PSCI`_. To test system suspend

								on Juno, at the linux shell prompt, issue the following command:


								::


								    echo +10 > /sys/class/rtc/rtc0/wakealarm

								    echo -n mem > /sys/power/state


								The Juno board should suspend to RAM and then wakeup after 10 seconds due to

								wakeup interrupt from RTC.


								--------------


								*Copyright (c) 2013-2018, Arm Limited and Contributors. All rights reserved.*


								.. _Linaro: `Linaro Release Notes`_

								.. _Linaro Release: `Linaro Release Notes`_

								.. _Linaro Release Notes: https://community.arm.com/dev-platforms/w/docs/226/old-linaro-release-notes

								.. _Linaro instructions: https://community.arm.com/dev-platforms/w/docs/304/linaro-software-deliverables

								.. _Instructions for using Linaro's deliverables on Juno: https://community.arm.com/dev-platforms/w/docs/303/juno

								.. _Arm Platforms Portal: https://community.arm.com/dev-platforms/

								.. _Development Studio 5 (DS-5): http://www.arm.com/products/tools/software-tools/ds-5/index.php

								.. _Linux master tree: https://github.com/torvalds/linux/tree/master/

								.. _Dia: https://wiki.gnome.org/Apps/Dia/Download

								.. _here: psci-lib-integration-guide.rst

								.. _Trusted Board Boot: trusted-board-boot.rst

								.. _TB_FW_CONFIG for FVP: ../plat/arm/board/fvp/fdts/fvp_tb_fw_config.dts

								.. _Secure-EL1 Payloads and Dispatchers: firmware-design.rst#user-content-secure-el1-payloads-and-dispatchers

								.. _Firmware Update: firmware-update.rst

								.. _Firmware Design: firmware-design.rst

								.. _mbed TLS Repository: https://github.com/ARMmbed/mbedtls.git

								.. _mbed TLS Security Center: https://tls.mbed.org/security

								.. _Arm's website: `FVP models`_

								.. _FVP models: https://developer.arm.com/products/system-design/fixed-virtual-platforms

								.. _Juno Getting Started Guide: http://infocenter.arm.com/help/topic/com.arm.doc.dui0928e/DUI0928E_juno_arm_development_platform_gsg.pdf

								.. _PSCI: http://infocenter.arm.com/help/topic/com.arm.doc.den0022d/Power_State_Coordination_Interface_PDD_v1_1_DEN0022D.pdf

								.. _Secure Partition Manager Design guide: secure-partition-manager-design.rst