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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 000000000..2f44fe817 --- /dev/null +++ b/docs/getting_started/build-options.rst @@ -0,0 +1,660 @@ +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``. + +- ``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 + :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`. + +- ``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. + +- ``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 + + 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 | + +-------+--------------+-------+-----+ + + This option defaults to 0 and this is an experimental feature. + 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. + +- ``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_PAUTH_REGS``: Boolean option that, when set to 1, enables + 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. Default value is 0 and this is an experimental feature. + 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. + +- ``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. + +- ``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. + +- ``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 overridden in each platform's Makefile or + in the build command line. + +- ``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_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 BL2_AT_EL3, BL31, and BL32 (TSP). 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_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", "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``. + +- ``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 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``. + +- ``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 `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, 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. + +- ``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: ``rsa``, ``rsa_1_5`` and ``ecdsa``. 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 | unavailable | + +-----------+------------------------------------+ + + * Only 2048 bits size is available with CryptoCell 712 SBROM release 1. + Only 3072 bits size is available with CryptoCell 712 SBROM release 2. + +- ``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. If this flag is enabled ``TRUSTED_BOARD_BOOT`` must be set. + This option defaults to 0 and is an experimental feature in the stage of + development. + +- ``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. + +- ``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. + +- ``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 :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 definitons 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. + +- ``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. + +- ``SPM_MM`` : Boolean option to enable the Management Mode (MM)-based Secure + Partition Manager (SPM) implementation. The default value is ``0``. + +- ``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. + + .. 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 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 + :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``. + +- ``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. + +- ``USE_DEBUGFS``: When set to 1 this option activates an EXPERIMENTAL feature + exposing a virtual filesystem interface through BL31 as a SiP SMC function. + Default is 0. + +- ``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. + +- ``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. + +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 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``. + +.. 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 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 + +-------------- + +*Copyright (c) 2019, Arm Limited. All rights reserved.* |