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diff --git a/docs/getting_started/build-options.rst b/docs/getting_started/build-options.rst new file mode 100644 index 0000000..80baf9c --- /dev/null +++ b/docs/getting_started/build-options.rst @@ -0,0 +1,1327 @@ +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. + +.. _build_options_common: + +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``. + +- ``AMU_RESTRICT_COUNTERS``: Register reads to the group 1 counters will return + zero at all but the highest implemented exception level. Reads from the + memory mapped view are unaffected by this control. + +- ``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_FEATURE``: Optional Arm Architecture build option which specifies + one or more feature modifiers. This option has the form ``[no]feature+...`` + and defaults to ``none``. It translates into compiler option + ``-march=armvX[.Y]-a+[no]feature+...``. See compiler's documentation for the + list of supported feature modifiers. + +- ``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 + :ref:`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 :ref:`Firmware Design`. + +- ``ARM_BL2_SP_LIST_DTS``: Path to DTS file snippet to override the hardcoded + SP nodes in tb_fw_config. + +- ``ARM_SPMC_MANIFEST_DTS`` : path to an alternate manifest file used as the + SPMC Core manifest. Valid when ``SPD=spmd`` is selected. + +- ``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. + +- ``RESET_TO_BL2``: Boolean option to enable BL2 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 BL2 entrypoint). + The default value is 0. + +- ``BL2_RUNS_AT_EL3``: This is an implicit flag to denote that BL2 runs at EL3. + While it is explicitly set to 1 when RESET_TO_BL2 is set to 1 it can also be + true in a 4-world system where RESET_TO_BL2 is 0. + +- ``BL2_ENABLE_SP_LOAD``: Boolean option to enable loading SP packages from the + FIP. Automatically enabled if ``SP_LAYOUT_FILE`` is provided. + +- ``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 RESET_TO_BL2 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 a + file that contains the BL31 private key in PEM format or a PKCS11 URI. If + ``SAVE_KEYS=1``, only a file is accepted and it 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 a + file that contains the BL32 private key in PEM format or a PKCS11 URI. If + ``SAVE_KEYS=1``, only a file is accepted and it 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 a + file that contains the BL33 private key in PEM format or a PKCS11 URI. If + ``SAVE_KEYS=1``, only a file is accepted and it will be used to save the key. + +- ``BRANCH_PROTECTION``: Numeric value to enable ARMv8.3 Pointer Authentication + and ARMv8.5 Branch Target Identification support for TF-A BL images themselves. + If enabled, it is needed to use a compiler that supports the option + ``-mbranch-protection``. Selects the branch protection features to use: +- 0: Default value turns off all types of branch protection +- 1: Enables all types of branch protection features +- 2: Return address signing to its standard level +- 3: Extend the signing to include leaf functions +- 4: Turn on branch target identification mechanism + + The table below summarizes ``BRANCH_PROTECTION`` values, GCC compilation options + and resulting PAuth/BTI features. + + +-------+--------------+-------+-----+ + | Value | GCC option | PAuth | BTI | + +=======+==============+=======+=====+ + | 0 | none | N | N | + +-------+--------------+-------+-----+ + | 1 | standard | Y | Y | + +-------+--------------+-------+-----+ + | 2 | pac-ret | Y | N | + +-------+--------------+-------+-----+ + | 3 | pac-ret+leaf | Y | N | + +-------+--------------+-------+-----+ + | 4 | bti | N | Y | + +-------+--------------+-------+-----+ + + This option defaults to 0. + Note that Pointer Authentication is enabled for Non-secure world + irrespective of the value of this option if the CPU supports it. + +- ``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. + +- ``BUILD_BASE``: Output directory for the build. Defaults to ``./build`` + +- ``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. + +- ``COT``: When Trusted Boot is enabled, selects the desired chain of trust. + Defaults to ``tbbr``. + +- ``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. + +- ``CTX_INCLUDE_MTE_REGS``: Numeric value to include Memory Tagging Extension + registers in cpu context. This must be enabled, if the platform wants to use + this feature in the Secure world and MTE is enabled at ELX. This flag can + take values 0 to 2, to align with the ``FEATURE_DETECTION`` mechanism. + Default value is 0. + +- ``CTX_INCLUDE_NEVE_REGS``: Numeric value, when set will cause the Armv8.4-NV + registers to be saved/restored when entering/exiting an EL2 execution + context. This flag can take values 0 to 2, to align with the + ``FEATURE_DETECTION`` mechanism. Default value is 0. + +- ``CTX_INCLUDE_PAUTH_REGS``: Numeric value to enable the Pointer + Authentication for Secure world. This will cause the ARMv8.3-PAuth registers + to be included when saving and restoring the CPU context as part of world + switch. This flag can take values 0 to 2, to align with ``FEATURE_DETECTION`` + mechanism. Default value is 0. + + Note that Pointer Authentication is enabled for Non-secure world irrespective + of the value of this flag if the CPU supports it. + +- ``DEBUG``: Chooses between a debug and release build. It can take either 0 + (release) or 1 (debug) as values. 0 is the default. + +- ``DECRYPTION_SUPPORT``: This build flag enables the user to select the + authenticated decryption algorithm to be used to decrypt firmware/s during + boot. It accepts 2 values: ``aes_gcm`` and ``none``. The default value of + this flag is ``none`` to disable firmware decryption which is an optional + feature as per TBBR. + +- ``DISABLE_BIN_GENERATION``: Boolean option to disable the generation + of the binary image. If set to 1, then only the ELF image is built. + 0 is the default. + +- ``DISABLE_MTPMU``: Numeric option to disable ``FEAT_MTPMU`` (Multi Threaded + PMU). ``FEAT_MTPMU`` is an optional feature available on Armv8.6 onwards. + This flag can take values 0 to 2, to align with the ``FEATURE_DETECTION`` + mechanism. Default is ``0``. + +- ``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. + +- ``E``: Boolean option to make warnings into errors. Default is 1. + + When specifying higher warnings levels (``W=1`` and higher), this option + defaults to 0. This is done to encourage contributors to use them, as they + are expected to produce warnings that would otherwise fail the build. New + contributions are still expected to build with ``W=0`` and ``E=1`` (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_AUXILIARY_COUNTERS``: Enables support for AMU auxiliary counters + (also known as group 1 counters). These are implementation-defined counters, + and as such require additional platform configuration. Default is 0. + +- ``ENABLE_AMU_FCONF``: Enables configuration of the AMU through FCONF, which + allows platforms with auxiliary counters to describe them via the + ``HW_CONFIG`` device tree blob. 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 enable 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 overridden in each platform's Makefile or + in the build command line. + +- ``ENABLE_FEAT_AMU``: Numeric value to enable Activity Monitor Unit + extensions. This flag can take the values 0 to 2, to align with the + ``FEATURE_DETECTION`` mechanism. 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. + This flag can take the values 0 to 2, the default is 0. + +- ``ENABLE_FEAT_AMUv1p1``: Numeric value to enable the ``FEAT_AMUv1p1`` + extension. ``FEAT_AMUv1p1`` is an optional feature available on Arm v8.6 + onwards. This flag can take the values 0 to 2, to align with the + ``FEATURE_DETECTION`` mechanism. Default value is ``0``. + +- ``ENABLE_FEAT_CSV2_2``: Numeric value to enable the ``FEAT_CSV2_2`` + extension. It allows access to the SCXTNUM_EL2 (Software Context Number) + register during EL2 context save/restore operations. ``FEAT_CSV2_2`` is an + optional feature available on Arm v8.0 onwards. This flag can take values + 0 to 2, to align with the ``FEATURE_DETECTION`` mechanism. + Default value is ``0``. + +- ``ENABLE_FEAT_DIT``: Numeric value to enable ``FEAT_DIT`` (Data Independent + Timing) extension. It allows setting the ``DIT`` bit of PSTATE in EL3. + ``FEAT_DIT`` is a mandatory architectural feature and is enabled from v8.4 + and upwards. This flag can take the values 0 to 2, to align with the + ``FEATURE_DETECTION`` mechanism. Default value is ``0``. + +- ``ENABLE_FEAT_ECV``: Numeric value to enable support for the Enhanced Counter + Virtualization feature, allowing for access to the CNTPOFF_EL2 (Counter-timer + Physical Offset register) during EL2 to EL3 context save/restore operations. + Its a mandatory architectural feature and is enabled from v8.6 and upwards. + This flag can take the values 0 to 2, to align with the ``FEATURE_DETECTION`` + mechanism. Default value is ``0``. + +- ``ENABLE_FEAT_FGT``: Numeric value to enable support for FGT (Fine Grain Traps) + feature allowing for access to the HDFGRTR_EL2 (Hypervisor Debug Fine-Grained + Read Trap Register) during EL2 to EL3 context save/restore operations. + Its a mandatory architectural feature and is enabled from v8.6 and upwards. + This flag can take the values 0 to 2, to align with the ``FEATURE_DETECTION`` + mechanism. Default value is ``0``. + +- ``ENABLE_FEAT_HCX``: Numeric value to set the bit SCR_EL3.HXEn in EL3 to + allow access to HCRX_EL2 (extended hypervisor control register) from EL2 as + well as adding HCRX_EL2 to the EL2 context save/restore operations. Its a + mandatory architectural feature and is enabled from v8.7 and upwards. This + flag can take the values 0 to 2, to align with the ``FEATURE_DETECTION`` + mechanism. Default value is ``0``. + +- ``ENABLE_FEAT_MTE_PERM``: Numeric value to enable support for + ``FEAT_MTE_PERM``, which introduces Allocation tag access permission to + memory region attributes. ``FEAT_MTE_PERM`` is a optional architectural + feature available from v8.9 and upwards. This flag can take the values 0 to + 2, to align with the ``FEATURE_DETECTION`` mechanism. Default value is + ``0``. + +- ``ENABLE_FEAT_PAN``: Numeric value to enable the ``FEAT_PAN`` (Privileged + Access Never) extension. ``FEAT_PAN`` adds a bit to PSTATE, generating a + permission fault for any privileged data access from EL1/EL2 to virtual + memory address, accessible at EL0, provided (HCR_EL2.E2H=1). It is a + mandatory architectural feature and is enabled from v8.1 and upwards. This + flag can take values 0 to 2, to align with the ``FEATURE_DETECTION`` + mechanism. Default value is ``0``. + +- ``ENABLE_FEAT_RNG``: Numeric value to enable the ``FEAT_RNG`` extension. + ``FEAT_RNG`` is an optional feature available on Arm v8.5 onwards. This + flag can take the values 0 to 2, to align with the ``FEATURE_DETECTION`` + mechanism. Default value is ``0``. + +- ``ENABLE_FEAT_RNG_TRAP``: Numeric value to enable the ``FEAT_RNG_TRAP`` + extension. This feature is only supported in AArch64 state. This flag can + take values 0 to 2, to align with the ``FEATURE_DETECTION`` mechanism. + Default value is ``0``. ``FEAT_RNG_TRAP`` is an optional feature from + Armv8.5 onwards. + +- ``ENABLE_FEAT_SB``: Boolean option to let the TF-A code use the ``FEAT_SB`` + (Speculation Barrier) instruction ``FEAT_SB`` is an optional feature and + defaults to ``0`` for pre-Armv8.5 CPUs, but is mandatory for Armv8.5 or + later CPUs. It is enabled from v8.5 and upwards and if needed can be + overidden from platforms explicitly. + +- ``ENABLE_FEAT_SEL2``: Numeric value to enable the ``FEAT_SEL2`` (Secure EL2) + extension. ``FEAT_SEL2`` is a mandatory feature available on Arm v8.4. + This flag can take values 0 to 2, to align with the ``FEATURE_DETECTION`` + mechanism. Default is ``0``. + +- ``ENABLE_FEAT_TWED``: Numeric value to enable the ``FEAT_TWED`` (Delayed + trapping of WFE Instruction) extension. ``FEAT_TWED`` is a optional feature + available on Arm v8.6. This flag can take values 0 to 2, to align with the + ``FEATURE_DETECTION`` mechanism. Default is ``0``. + + When ``ENABLE_FEAT_TWED`` is set to ``1``, WFE instruction trapping gets + delayed by the amount of value in ``TWED_DELAY``. + +- ``ENABLE_FEAT_VHE``: Numeric value to enable the ``FEAT_VHE`` (Virtualization + Host Extensions) extension. It allows access to CONTEXTIDR_EL2 register + during EL2 context save/restore operations.``FEAT_VHE`` is a mandatory + architectural feature and is enabled from v8.1 and upwards. It can take + values 0 to 2, to align with the ``FEATURE_DETECTION`` mechanism. + Default value is ``0``. + +- ``ENABLE_FEAT_TCR2``: Numeric value to set the bit SCR_EL3.ENTCR2 in EL3 to + allow access to TCR2_EL2 (extended translation control) from EL2 as + well as adding TCR2_EL2 to the EL2 context save/restore operations. Its a + mandatory architectural feature and is enabled from v8.9 and upwards. This + flag can take the values 0 to 2, to align with the ``FEATURE_DETECTION`` + mechanism. Default value is ``0``. + +- ``ENABLE_FEAT_S2PIE``: Numeric value to enable support for FEAT_S2PIE + at EL2 and below, and context switch relevant registers. This flag + can take the values 0 to 2, to align with the ``FEATURE_DETECTION`` + mechanism. Default value is ``0``. + +- ``ENABLE_FEAT_S1PIE``: Numeric value to enable support for FEAT_S1PIE + at EL2 and below, and context switch relevant registers. This flag + can take the values 0 to 2, to align with the ``FEATURE_DETECTION`` + mechanism. Default value is ``0``. + +- ``ENABLE_FEAT_S2POE``: Numeric value to enable support for FEAT_S2POE + at EL2 and below, and context switch relevant registers. This flag + can take the values 0 to 2, to align with the ``FEATURE_DETECTION`` + mechanism. Default value is ``0``. + +- ``ENABLE_FEAT_S1POE``: Numeric value to enable support for FEAT_S1POE + at EL2 and below, and context switch relevant registers. This flag + can take the values 0 to 2, to align with the ``FEATURE_DETECTION`` + mechanism. Default value is ``0``. + +- ``ENABLE_FEAT_GCS``: Numeric value to set the bit SCR_EL3.GCSEn in EL3 to + allow use of Guarded Control Stack from EL2 as well as adding the GCS + registers to the EL2 context save/restore operations. This flag can take + the values 0 to 2, to align with the ``FEATURE_DETECTION`` mechanism. + Default value is ``0``. + +- ``ENABLE_LTO``: Boolean option to enable Link Time Optimization (LTO) + support in GCC for TF-A. This option is currently only supported for + AArch64. Default is 0. + +- ``ENABLE_FEAT_MPAM``: Numeric value 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. + + This flag can take values 0 to 2, to align with the ``FEATURE_DETECTION`` + mechanism. When this option is set to ``1`` or ``2``, 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 ``2`` since MPAM is enabled by default for NS world only. + The flag is automatically disabled when the target + architecture is AArch32. + +- ``ENABLE_MPMM``: Boolean option to enable support for the Maximum Power + Mitigation Mechanism supported by certain Arm cores, which allows the SoC + firmware to detect and limit high activity events to assist in SoC processor + power domain dynamic power budgeting and limit the triggering of whole-rail + (i.e. clock chopping) responses to overcurrent conditions. Defaults to ``0``. + +- ``ENABLE_MPMM_FCONF``: Enables configuration of MPMM through FCONF, which + allows platforms with cores supporting MPMM to describe them via the + ``HW_CONFIG`` device tree blob. Default is 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 BL2, BL31, and BL32 (TSP) for AARCH64 binaries, and + in BL32 (SP_min) for AARCH32. 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_NS`` : Numeric value to enable Statistical Profiling + extensions. This is an optional architectural feature for AArch64. + This flag can take the values 0 to 2, to align with the ``FEATURE_DETECTION`` + mechanism. The default is 2 but is automatically disabled when the target + architecture is AArch32. + +- ``ENABLE_SVE_FOR_NS``: Numeric value 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 by + default and controlled with ENABLE_SVE_FOR_SWD. + 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`` + enabled. This flag can take the values 0 to 2, to align with the + ``FEATURE_DETECTION`` mechanism. At this time, this build option cannot be + used on systems that have SPM_MM enabled. The default is 1. + +- ``ENABLE_SVE_FOR_SWD``: Boolean option to enable SVE for the Secure world. + SVE is an optional architectural feature for AArch64. Note that this option + requires ENABLE_SVE_FOR_NS to be enabled. The default is 0 and it 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", "default" and "none". The + default value is set to "none". "strong" is the recommended stack protection + level if this feature is desired. "none" disables the stack protection. For + all values other than "none", 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``. + +- ``ENCRYPT_BL31``: Binary flag to enable encryption of BL31 firmware. This + flag depends on ``DECRYPTION_SUPPORT`` build flag. + +- ``ENCRYPT_BL32``: Binary flag to enable encryption of Secure BL32 payload. + This flag depends on ``DECRYPTION_SUPPORT`` build flag. + +- ``ENC_KEY``: A 32-byte (256-bit) symmetric key in hex string format. It could + either be SSK or BSSK depending on ``FW_ENC_STATUS`` flag. This value depends + on ``DECRYPTION_SUPPORT`` build flag. + +- ``ENC_NONCE``: A 12-byte (96-bit) encryption nonce or Initialization Vector + (IV) in hex string format. This value depends on ``DECRYPTION_SUPPORT`` + build flag. + +- ``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. + +- ``ETHOSN_NPU_DRIVER``: boolean option to enable a SiP service that can + configure an Arm® Ethos™-N NPU. To use this service the target platform's + ``HW_CONFIG`` must include the device tree nodes for the NPU. Currently, only + the Arm Juno platform has this included in its ``HW_CONFIG`` and the platform + only loads the ``HW_CONFIG`` in AArch64 builds. Default is 0. + +- ``ETHOSN_NPU_TZMP1``: boolean option to enable TZMP1 support for the + Arm® Ethos™-N NPU. Requires ``ETHOSN_NPU_DRIVER`` and + ``TRUSTED_BOARD_BOOT`` to be enabled. + +- ``ETHOSN_NPU_FW``: location of the NPU firmware binary + (```ethosn.bin```). This firmware image will be included in the FIP and + loaded at runtime. + +- ``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. The exception to this rule is when + ``SPMD_SPM_AT_SEL2`` is set to ``1``, in which case, only exceptions + occuring during normal world execution, are trapped to EL3. Any exception + trapped during secure world execution are trapped to the SPMC. This is + supported only for AArch64 builds. + +- ``EVENT_LOG_LEVEL``: Chooses the log level to use for Measured Boot when + ``MEASURED_BOOT`` is enabled. For a list of valid values, see ``LOG_LEVEL``. + Default value is 40 (LOG_LEVEL_INFO). + +- ``FAULT_INJECTION_SUPPORT``: ARMv8.4 extensions 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``. + +- ``FW_ENC_STATUS``: Top level firmware's encryption numeric flag, values: + + :: + + 0: Encryption is done with Secret Symmetric Key (SSK) which is common + for a class of devices. + 1: Encryption is done with Binding Secret Symmetric Key (BSSK) which is + unique per device. + + This flag depends on ``DECRYPTION_SUPPORT`` build flag. + +- ``GENERATE_COT``: Boolean flag used to build and execute the ``cert_create`` + tool to create certificates as per the Chain of Trust described in + :ref:`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 :ref:`platform abstraction layer<platform Interrupt Controller API>` and + :ref:`Interrupt Management Framework<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. + +- ``HANDLE_EA_EL3_FIRST_NS``: When set to ``1``, External Aborts and SError + Interrupts, resulting from errors in NS world, 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, newer systems exist where CPUs' entry to and exit from coherency + is managed in hardware. Such systems require software to only initiate these + 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. + + If this flag is disabled while the platform which TF-A is compiled for + includes cores that manage coherency in hardware, then a compilation error is + generated. This is based on the fact that a system cannot have, at the same + time, cores that manage coherency in hardware and cores that don't. In other + words, a platform cannot have, at the same time, cores that require + ``HW_ASSISTED_COHERENCY=1`` and cores that require + ``HW_ASSISTED_COHERENCY=0``. + + 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. + +- ``IMPDEF_SYSREG_TRAP``: Numeric value to enable the handling traps for + implementation defined system register accesses from lower ELs. Default + value is ``0``. + +- ``INVERTED_MEMMAP``: memmap tool print by default lower addresses at the + bottom, higher addresses at the top. This build flag can be set to '1' to + invert this behavior. Lower addresses will be printed at the top and higher + addresses at the bottom. + +- ``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 5 values: ``rsa``, ``rsa_1_5``, ``ecdsa``, ``ecdsa-brainpool-regular`` + and ``ecdsa-brainpool-twisted``. The option ``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. + +- ``KEY_SIZE``: This build flag enables the user to select the key size for + the algorithm specified by ``KEY_ALG``. The valid values for ``KEY_SIZE`` + depend on the chosen algorithm and the cryptographic module. + + +---------------------------+------------------------------------+ + | KEY_ALG | Possible key sizes | + +===========================+====================================+ + | rsa | 1024 , 2048 (default), 3072, 4096 | + +---------------------------+------------------------------------+ + | ecdsa | 256 (default), 384 | + +---------------------------+------------------------------------+ + | ecdsa-brainpool-regular | unavailable | + +---------------------------+------------------------------------+ + | ecdsa-brainpool-twisted | unavailable | + +---------------------------+------------------------------------+ + +- ``HASH_ALG``: This build flag enables the user to select the secure hash + algorithm. It accepts 3 values: ``sha256``, ``sha384`` and ``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. + +- ``MEASURED_BOOT``: Boolean flag to include support for the Measured Boot + feature. This flag can be enabled with ``TRUSTED_BOARD_BOOT`` in order to + provide trust that the code taking the measurements and recording them has + not been tampered with. + + This option defaults to 0. + +- ``MARCH_DIRECTIVE``: used to pass a -march option from the platform build + options to the compiler. An example usage: + + .. code:: make + + MARCH_DIRECTIVE := -march=armv8.5-a + +- ``NON_TRUSTED_WORLD_KEY``: This option is used when ``GENERATE_COT=1``. It + specifies a file that contains the Non-Trusted World private key in PEM + format or a PKCS11 URI. If ``SAVE_KEYS=1``, only a file is accepted and it + 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. + +- ``OPTEE_SP_FW_CONFIG``: DTC build flag to include OP-TEE as SP in + tb_fw_config device tree. This flag is defined only when + ``ARM_SPMC_MANIFEST_DTS`` manifest file name contains pattern optee_sp. + +- ``OVERRIDE_LIBC``: This option allows platforms to override the default libc + for the BL image. It can be either 0 (include) or 1 (remove). The default + value is 0. + +- ``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: 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. + +- ``PSCI_OS_INIT_MODE``: Boolean flag to enable support for optional PSCI + OS-initiated mode. This option defaults to 0. + +- ``ENABLE_FEAT_RAS``: Boolean flag to 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. This flag can take the values 0 or 1. The default value is 0. + NOTE: This flag enables use of IESB capability to reduce entry latency into + EL3 even when RAS error handling is not performed on the platform. Hence this + flag is recommended to be turned on Armv8.2 and later CPUs. + +- ``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 a + file that contains the ROT private key in PEM format or a PKCS11 URI and + enforces public key hash generation. If ``SAVE_KEYS=1``, only a file is + accepted and it 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 a + file that contains the SCP_BL2 private key in PEM format or a PKCS11 URI. + If ``SAVE_KEYS=1``, only a file is accepted and it 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 :ref:`Firmware Design`. This flag is disabled by default + and affects all BL images. + +- ``SEPARATE_NOBITS_REGION``: Setting this option to ``1`` allows the NOBITS + sections of BL31 (.bss, stacks, page tables, and coherent memory) to be + allocated in RAM discontiguous from the loaded firmware image. When set, the + platform is expected to provide definitions for ``BL31_NOBITS_BASE`` and + ``BL31_NOBITS_LIMIT``. When the option is ``0`` (the default), NOBITS + sections are placed in RAM immediately following the loaded firmware image. + +- ``SEPARATE_BL2_NOLOAD_REGION``: Setting this option to ``1`` allows the + NOLOAD sections of BL2 (.bss, stacks, page tables) to be allocated in RAM + discontiguous from loaded firmware images. When set, the platform need to + provide definitions of ``BL2_NOLOAD_START`` and ``BL2_NOLOAD_LIMIT``. This + flag is disabled by default and NOLOAD sections are placed in RAM immediately + following the loaded firmware image. + +- ``SMC_PCI_SUPPORT``: This option allows platforms to handle PCI configuration + access requests via a standard SMCCC defined in `DEN0115`_. When combined with + UEFI+ACPI this can provide a certain amount of OS forward compatibility + with newer platforms that aren't ECAM compliant. + +- ``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``. The SPM Dispatcher standard service is located in + services/std_svc/spmd and enabled by ``SPD=spmd``. The SPM Dispatcher + cannot be enabled when the ``SPM_MM`` option is enabled. + +- ``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. + +- ``SPMC_AT_EL3`` : This boolean option is used jointly with the SPM + Dispatcher option (``SPD=spmd``). When enabled (1) it indicates the SPMC + component runs at the EL3 exception level. The default value is ``0`` ( + disabled). This configuration supports pre-Armv8.4 platforms (aka not + implementing the ``FEAT_SEL2`` extension). + +- ``SPMC_AT_EL3_SEL0_SP`` : Boolean option to enable SEL0 SP load support when + ``SPMC_AT_EL3`` is enabled. The default value if ``0`` (disabled). This + option cannot be enabled (``1``) when (``SPMC_AT_EL3``) is disabled. + +- ``SPMC_OPTEE`` : This boolean option is used jointly with the SPM + Dispatcher option (``SPD=spmd``) and with ``SPMD_SPM_AT_SEL2=0`` to + indicate that the SPMC at S-EL1 is OP-TEE and an OP-TEE specific loading + mechanism should be used. + +- ``SPMD_SPM_AT_SEL2`` : This boolean option is used jointly with the SPM + Dispatcher option (``SPD=spmd``). When enabled (1) it indicates the SPMC + component runs at the S-EL2 exception level provided by the ``FEAT_SEL2`` + extension. This is the default when enabling the SPM Dispatcher. When + disabled (0) it indicates the SPMC component runs at the S-EL1 execution + state or at EL3 if ``SPMC_AT_EL3`` is enabled. The latter configurations + support pre-Armv8.4 platforms (aka not implementing the ``FEAT_SEL2`` + extension). + +- ``SPM_MM`` : Boolean option to enable the Management Mode (MM)-based Secure + Partition Manager (SPM) implementation. The default value is ``0`` + (disabled). This option cannot be enabled (``1``) when SPM Dispatcher is + enabled (``SPD=spmd``). + +- ``SP_LAYOUT_FILE``: Platform provided path to JSON file containing the + description of secure partitions. The build system will parse this file and + package all secure partition blobs into the FIP. This file is not + necessarily part of TF-A tree. Only available when ``SPD=spmd``. + +- ``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. + +- ``SVE_VECTOR_LEN``: SVE vector length to configure in ZCR_EL3. + Platforms can configure this if they need to lower the hardware + limit, for example due to asymmetric configuration or limitations of + software run at lower ELs. The default is the architectural maximum + of 2048 which should be suitable for most configurations, the + hardware will limit the effective VL to the maximum physically supported + VL. + +- ``TRNG_SUPPORT``: Setting this to ``1`` enables support for True + Random Number Generator Interface to BL31 image. This defaults to ``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. + + .. warning:: + 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 a file that contains the Trusted World private key in PEM + format or a PKCS11 URI. If ``SAVE_KEYS=1``, only a file is accepted and + it 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 + :ref:`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``. + +- ``TS_SP_FW_CONFIG``: DTC build flag to include Trusted Services (Crypto and + internal-trusted-storage) as SP in tb_fw_config device tree. + +- ``TWED_DELAY``: Numeric value to be set in order to delay the trapping of + WFE instruction. ``ENABLE_FEAT_TWED`` build option must be enabled to set + this delay. It can take values in the range (0-15). Default value is ``0`` + and based on this value, 2^(TWED_DELAY + 8) cycles will be delayed. + Platforms need to explicitly update this value based on their requirements. + +- ``USE_ARM_LINK``: This flag determines whether to enable support for ARM + linker. When the ``LINKER`` build variable points to the armlink linker, + this flag is enabled automatically. To enable support for armlink, platforms + will have to provide a scatter file for the BL image. Currently, Tegra + platforms use the armlink support to compile BL3-1 images. + +- ``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 :ref:`Firmware Design`). It can take the value 1 + (Coherent memory region is included) or 0 (Coherent memory region is + excluded). Default is 1. + +- ``ARM_IO_IN_DTB``: This flag determines whether to use IO based on the + firmware configuration framework. This will move the io_policies into a + configuration device tree, instead of static structure in the code base. + +- ``COT_DESC_IN_DTB``: This flag determines whether to create COT descriptors + at runtime using fconf. If this flag is enabled, COT descriptors are + statically captured in tb_fw_config file in the form of device tree nodes + and properties. Currently, COT descriptors used by BL2 are moved to the + device tree and COT descriptors used by BL1 are retained in the code + base statically. + +- ``SDEI_IN_FCONF``: This flag determines whether to configure SDEI setup in + runtime using firmware configuration framework. The platform specific SDEI + shared and private events configuration is retrieved from device tree rather + than static C structures at compile time. This is only supported if + SDEI_SUPPORT build flag is enabled. + +- ``SEC_INT_DESC_IN_FCONF``: This flag determines whether to configure Group 0 + and Group1 secure interrupts using the firmware configuration framework. The + platform specific secure interrupt property descriptor is retrieved from + device tree in runtime rather than depending on static C structure at compile + time. + +- ``USE_ROMLIB``: This flag determines whether library at ROM will be used. + This feature creates a library of functions to be placed in ROM and thus + reduces SRAM usage. Refer to :ref:`Library at ROM` for further details. Default + is 0. + +- ``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. + +- ``W``: Warning level. Some compiler warning options of interest have been + regrouped and put in the root Makefile. This flag can take the values 0 to 3, + each level enabling more warning options. Default is 0. + + This option is closely related to the ``E`` option, which enables + ``-Werror``. + + - ``W=0`` (default) + + Enables a wide assortment of warnings, most notably ``-Wall`` and + ``-Wextra``, as well as various bad practices and things that are likely to + result in errors. Includes some compiler specific flags. No warnings are + expected at this level for any build. + + - ``W=1`` + + Enables warnings we want the generic build to include but are too time + consuming to fix at the moment. It re-enables warnings taken out for + ``W=0`` builds (a few of the ``-Wextra`` additions). This level is expected + to eventually be merged into ``W=0``. Some warnings are expected on some + builds, but new contributions should not introduce new ones. + + - ``W=2`` (recommended) + + Enables warnings we want the generic build to include but cannot be enabled + due to external libraries. This level is expected to eventually be merged + into ``W=0``. Lots of warnings are expected, primarily from external + libraries like zlib and compiler-rt, but new controbutions should not + introduce new ones. + + - ``W=3`` + + Enables warnings that are informative but not necessary and generally too + verbose and frequently ignored. A very large number of warnings are + expected. + + The exact set of warning flags depends on the compiler and TF-A warning + level, however they are all succinctly set in the top-level Makefile. Please + refer to the `GCC`_ or `Clang`_ documentation for more information on the + individual flags. + +- ``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. + +- ``SUPPORT_STACK_MEMTAG``: This flag determines whether to enable memory + tagging for stack or not. It accepts 2 values: ``yes`` and ``no``. The + default value of this flag is ``no``. Note this option must be enabled only + for ARM architecture greater than Armv8.5-A. + +- ``ERRATA_SPECULATIVE_AT``: This flag determines whether to enable ``AT`` + speculative errata workaround or not. It accepts 2 values: ``1`` and ``0``. + The default value of this flag is ``0``. + + ``AT`` speculative errata workaround disables stage1 page table walk for + lower ELs (EL1 and EL0) in EL3 so that ``AT`` speculative fetch at any point + produces either the correct result or failure without TLB allocation. + + This boolean option enables errata for all below CPUs. + + +---------+--------------+-------------------------+ + | Errata | CPU | Workaround Define | + +=========+==============+=========================+ + | 1165522 | Cortex-A76 | ``ERRATA_A76_1165522`` | + +---------+--------------+-------------------------+ + | 1319367 | Cortex-A72 | ``ERRATA_A72_1319367`` | + +---------+--------------+-------------------------+ + | 1319537 | Cortex-A57 | ``ERRATA_A57_1319537`` | + +---------+--------------+-------------------------+ + | 1530923 | Cortex-A55 | ``ERRATA_A55_1530923`` | + +---------+--------------+-------------------------+ + | 1530924 | Cortex-A53 | ``ERRATA_A53_1530924`` | + +---------+--------------+-------------------------+ + + .. note:: + This option is enabled by build only if platform sets any of above defines + mentioned in ’Workaround Define' column in the table. + If this option is enabled for the EL3 software then EL2 software also must + implement this workaround due to the behaviour of the errata mentioned + in new SDEN document which will get published soon. + +- ``RAS_TRAP_NS_ERR_REC_ACCESS``: This flag enables/disables the SCR_EL3.TERR + bit, to trap access to the RAS ERR and RAS ERX registers from lower ELs. + This flag is disabled by default. + +- ``OPENSSL_DIR``: This option is used to provide the path to a directory on the + host machine where a custom installation of OpenSSL is located, which is used + to build the certificate generation, firmware encryption and FIP tools. If + this option is not set, the default OS installation will be used. + +- ``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. + +- ``ENABLE_BRBE_FOR_NS``: Numeric value to enable access to the branch record + buffer registers from NS ELs when FEAT_BRBE is implemented. BRBE is an + optional architectural feature for AArch64. This flag can take the values + 0 to 2, to align with the ``FEATURE_DETECTION`` mechanism. The default is 0 + and it is automatically disabled when the target architecture is AArch32. + +- ``ENABLE_TRBE_FOR_NS``: Numeric value to enable access of trace buffer + control registers from NS ELs, NS-EL2 or NS-EL1(when NS-EL2 is implemented + but unused) when FEAT_TRBE is implemented. TRBE is an optional architectural + feature for AArch64. This flag can take the values 0 to 2, to align with the + ``FEATURE_DETECTION`` mechanism. The default is 0 and it is automatically + disabled when the target architecture is AArch32. + +- ``ENABLE_SYS_REG_TRACE_FOR_NS``: Numeric value to enable trace system + registers access from NS ELs, NS-EL2 or NS-EL1 (when NS-EL2 is implemented + but unused). This feature is available if trace unit such as ETMv4.x, and + ETE(extending ETM feature) is implemented. This flag can take the values + 0 to 2, to align with the ``FEATURE_DETECTION`` mechanism. The default is 0. + +- ``ENABLE_TRF_FOR_NS``: Numeric value to enable trace filter control registers + access from NS ELs, NS-EL2 or NS-EL1 (when NS-EL2 is implemented but unused), + if FEAT_TRF is implemented. This flag can take the values 0 to 2, to align + with the ``FEATURE_DETECTION`` mechanism. This flag is disabled by default. + +- ``PLAT_RSS_NOT_SUPPORTED``: Boolean option to enable the usage of the PSA + APIs on platforms that doesn't support RSS (providing Arm CCA HES + functionalities). When enabled (``1``), a mocked version of the APIs are used. + The default value is 0. + +- ``CONDITIONAL_CMO``: Boolean option to enable call to platform-defined routine + ``plat_can_cmo`` which will return zero if cache management operations should + be skipped and non-zero otherwise. By default, this option is disabled which + means platform hook won't be checked and CMOs will always be performed when + related functions are called. + +- ``ERRATA_ABI_SUPPORT``: Boolean option to enable support for Errata management + firmware interface for the BL31 image. By default its disabled (``0``). + +- ``ERRATA_NON_ARM_INTERCONNECT``: Boolean option to enable support for the + errata mitigation for platforms with a non-arm interconnect using the errata + ABI. By default its disabled (``0``). + +- ``ENABLE_CONSOLE_GETC``: Boolean option to enable `getc()` feature in console + driver(s). By default it is disabled (``0``) because it constitutes an attack + vector into TF-A by potentially allowing an attacker to inject arbitrary data. + This option should only be enabled on a need basis if there is a use case for + reading characters from the console. + +GICv3 driver options +-------------------- + +GICv3 driver files are included using directive: + +``include drivers/arm/gic/v3/gicv3.mk`` + +The driver can be configured with the following options set in the platform +makefile: + +- ``GICV3_SUPPORT_GIC600``: Add support for the GIC-600 variants of GICv3. + Enabling this option will add runtime detection support for the + GIC-600, so is safe to select even for a GIC500 implementation. + This option defaults to 0. + +- ``GICV3_SUPPORT_GIC600AE_FMU``: Add support for the Fault Management Unit + for GIC-600 AE. Enabling this option will introduce support to initialize + the FMU. Platforms should call the init function during boot to enable the + FMU and its safety mechanisms. This option defaults to 0. + +- ``GICV3_IMPL_GIC600_MULTICHIP``: Selects GIC-600 variant with multichip + functionality. This option defaults to 0 + +- ``GICV3_OVERRIDE_DISTIF_PWR_OPS``: Allows override of default implementation + of ``arm_gicv3_distif_pre_save`` and ``arm_gicv3_distif_post_restore`` + functions. This is required for FVP platform which need to simulate GIC save + and restore during SYSTEM_SUSPEND without powering down GIC. Default is 0. + +- ``GIC_ENABLE_V4_EXTN`` : Enables GICv4 related changes in GICv3 driver. + This option defaults to 0. + +- ``GIC_EXT_INTID``: When set to ``1``, GICv3 driver will support extended + PPI (1056-1119) and SPI (4096-5119) range. This option defaults to 0. + +Debugging options +----------------- + +To compile a debug version and make the build more verbose use + +.. code:: shell + + make PLAT=<platform> DEBUG=1 V=1 all + +AArch64 GCC 11 uses DWARF version 5 debugging symbols by default. Some tools +(for example Arm-DS) 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, 3, 4 or 5. Setting +the version to 4 is recommended for Arm-DS. + +When debugging logic problems it might also be useful to disable all compiler +optimizations by using ``-O0``. + +.. warning:: + 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 :ref:`Firmware Design`). + +Extra debug options can be passed to the build system by setting ``CFLAGS`` or +``LDFLAGS``: + +.. code:: shell + + 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 :ref:`build_options_common` +section. In this case, the developer may take control of the target using a +debugger when indicated by the console output. When using Arm-DS, 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 + +.. _build_options_experimental: + +Experimental build options +--------------------------- + +Common build options +~~~~~~~~~~~~~~~~~~~~ + +- ``DRTM_SUPPORT``: Boolean flag to enable support for Dynamic Root of Trust + for Measurement (DRTM). This feature has trust dependency on BL31 for taking + the measurements and recording them as per `PSA DRTM specification`_. For + platforms which use BL2 to load/authenticate BL31 ``TRUSTED_BOARD_BOOT`` can + be used and for the platforms which use ``RESET_TO_BL31`` platform owners + should have mechanism to authenticate BL31. This option defaults to 0. + +- ``ENABLE_RME``: Numeric value to enable support for the ARMv9 Realm + Management Extension. This flag can take the values 0 to 2, to align with + the ``FEATURE_DETECTION`` mechanism. Default value is 0. + +- ``ENABLE_SME_FOR_NS``: Numeric value to enable Scalable Matrix Extension + (SME), SVE, and FPU/SIMD for the non-secure world only. These features share + registers so are enabled together. Using this option without + ENABLE_SME_FOR_SWD=1 will cause SME, SVE, and FPU/SIMD instructions in secure + world to trap to EL3. Requires ``ENABLE_SVE_FOR_NS`` to be set as SME is a + superset of SVE. SME is an optional architectural feature for AArch64. + At this time, this build option cannot be used on systems that have + SPD=spmd/SPM_MM and atempting to build with this option will fail. + This flag can take the values 0 to 2, to align with the ``FEATURE_DETECTION`` + mechanism. Default is 0. + +- ``ENABLE_SME2_FOR_NS``: Numeric value to enable Scalable Matrix Extension + version 2 (SME2) for the non-secure world only. SME2 is an optional + architectural feature for AArch64. + This should be set along with ENABLE_SME_FOR_NS=1, if not, the default SME + accesses will still be trapped. This flag can take the values 0 to 2, to + align with the ``FEATURE_DETECTION`` mechanism. Default is 0. + +- ``ENABLE_SME_FOR_SWD``: Boolean option to enable the Scalable Matrix + Extension for secure world. Used along with SVE and FPU/SIMD. + ENABLE_SME_FOR_NS and ENABLE_SVE_FOR_SWD must also be set to use this. + Default is 0. + +- ``ENABLE_SPMD_LP`` : This boolean option is used jointly with the SPM + Dispatcher option (``SPD=spmd``). When enabled (1) it indicates support + for logical partitions in EL3, managed by the SPMD as defined in the + FF-A v1.2 specification. This flag is disabled by default. This flag + must not be used if ``SPMC_AT_EL3`` is enabled. + +- ``FEATURE_DETECTION``: Boolean option to enable the architectural features + detection mechanism. It detects whether the Architectural features enabled + through feature specific build flags are supported by the PE or not by + validating them either at boot phase or at runtime based on the value + possessed by the feature flag (0 to 2) and report error messages at an early + stage. This flag will also enable errata ordering checking for ``DEBUG`` + builds. + + This prevents and benefits us from EL3 runtime exceptions during context save + and restore routines guarded by these build flags. Henceforth validating them + before their usage provides more control on the actions taken under them. + + The mechanism permits the build flags to take values 0, 1 or 2 and + evaluates them accordingly. + + Lets consider ``ENABLE_FEAT_HCX``, build flag for ``FEAT_HCX`` as an example: + + :: + + ENABLE_FEAT_HCX = 0: Feature disabled statically at compile time. + ENABLE_FEAT_HCX = 1: Feature Enabled and the flag is validated at boottime. + ENABLE_FEAT_HCX = 2: Feature Enabled and the flag is validated at runtime. + + In the above example, if the feature build flag, ``ENABLE_FEAT_HCX`` set to + 0, feature is disabled statically during compilation. If it is defined as 1, + feature is validated, wherein FEAT_HCX is detected at boot time. In case not + implemented by the PE, a hard panic is generated. Finally, if the flag is set + to 2, feature is validated at runtime. + + Note that the entire implementation is divided into two phases, wherein as + as part of phase-1 we are supporting the values 0,1. Value 2 is currently not + supported and is planned to be handled explicilty in phase-2 implementation. + + ``FEATURE_DETECTION`` macro is disabled by default. Platforms can explicitly + make use of this by mechanism, by enabling it to validate whether they have + set their build flags properly at an early phase. + +- ``PSA_CRYPTO``: Boolean option for enabling MbedTLS PSA crypto APIs support. + The platform will use PSA compliant Crypto APIs during authentication and + image measurement process by enabling this option. It uses APIs defined as + per the `PSA Crypto API specification`_. This feature is only supported if + using MbedTLS 3.x version. It is disabled (``0``) by default. + +- ``TRANSFER_LIST``: Setting this to ``1`` enables support for Firmware + Handoff using Transfer List defined in `Firmware Handoff specification`_. + This defaults to ``0``. Current implementation follows the Firmware Handoff + specification v0.9. + +- ``USE_DEBUGFS``: When set to 1 this option exposes a virtual filesystem + interface through BL31 as a SiP SMC function. + Default is disabled (0). + +Firmware update options +~~~~~~~~~~~~~~~~~~~~~~~ + +- ``PSA_FWU_SUPPORT``: Enable the firmware update mechanism as per the + `PSA FW update specification`_. The default value is 0. + PSA firmware update implementation has few limitations, such as: + + - BL2 is not part of the protocol-updatable images. If BL2 needs to + be updated, then it should be done through another platform-defined + mechanism. + + - It assumes the platform's hardware supports CRC32 instructions. + +- ``NR_OF_FW_BANKS``: Define the number of firmware banks. This flag is used + in defining the firmware update metadata structure. This flag is by default + set to '2'. + +- ``NR_OF_IMAGES_IN_FW_BANK``: Define the number of firmware images in each + firmware bank. Each firmware bank must have the same number of images as per + the `PSA FW update specification`_. + This flag is used in defining the firmware update metadata structure. This + flag is by default set to '1'. + +-------------- + +*Copyright (c) 2019-2023, Arm Limited. All rights reserved.* + +.. _DEN0115: https://developer.arm.com/docs/den0115/latest +.. _PSA FW update specification: https://developer.arm.com/documentation/den0118/a/ +.. _PSA DRTM specification: https://developer.arm.com/documentation/den0113/a +.. _GCC: https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html +.. _Clang: https://clang.llvm.org/docs/DiagnosticsReference.html +.. _Firmware Handoff specification: https://github.com/FirmwareHandoff/firmware_handoff/releases/tag/v0.9 +.. _PSA Crypto API specification: https://armmbed.github.io/mbed-crypto/html/ |