1Build Options 2============= 3 4The TF-A build system supports the following build options. Unless mentioned 5otherwise, these options are expected to be specified at the build command 6line and are not to be modified in any component makefiles. Note that the 7build system doesn't track dependency for build options. Therefore, if any of 8the build options are changed from a previous build, a clean build must be 9performed. 10 11.. _build_options_common: 12 13Common build options 14-------------------- 15 16- ``AARCH32_INSTRUCTION_SET``: Choose the AArch32 instruction set that the 17 compiler should use. Valid values are T32 and A32. It defaults to T32 due to 18 code having a smaller resulting size. 19 20- ``AARCH32_SP`` : Choose the AArch32 Secure Payload component to be built as 21 as the BL32 image when ``ARCH=aarch32``. The value should be the path to the 22 directory containing the SP source, relative to the ``bl32/``; the directory 23 is expected to contain a makefile called ``<aarch32_sp-value>.mk``. 24 25- ``AMU_RESTRICT_COUNTERS``: Register reads to the group 1 counters will return 26 zero at all but the highest implemented exception level. External 27 memory-mapped debug accesses are unaffected by this control. 28 The default value is 1 for all platforms. 29 30- ``ARCH`` : Choose the target build architecture for TF-A. It can take either 31 ``aarch64`` or ``aarch32`` as values. By default, it is defined to 32 ``aarch64``. 33 34- ``ARM_ARCH_FEATURE``: Optional Arm Architecture build option which specifies 35 one or more feature modifiers. This option has the form ``[no]feature+...`` 36 and defaults to ``none``. It translates into compiler option 37 ``-march=armvX[.Y]-a+[no]feature+...``. See compiler's documentation for the 38 list of supported feature modifiers. 39 40- ``ARM_ARCH_MAJOR``: The major version of Arm Architecture to target when 41 compiling TF-A. Its value must be numeric, and defaults to 8 . See also, 42 *Armv8 Architecture Extensions* and *Armv7 Architecture Extensions* in 43 :ref:`Firmware Design`. 44 45- ``ARM_ARCH_MINOR``: The minor version of Arm Architecture to target when 46 compiling TF-A. Its value must be a numeric, and defaults to 0. See also, 47 *Armv8 Architecture Extensions* in :ref:`Firmware Design`. 48 49- ``ARM_BL2_SP_LIST_DTS``: Path to DTS file snippet to override the hardcoded 50 SP nodes in tb_fw_config. 51 52- ``ARM_SPMC_MANIFEST_DTS`` : path to an alternate manifest file used as the 53 SPMC Core manifest. Valid when ``SPD=spmd`` is selected. 54 55- ``BL2``: This is an optional build option which specifies the path to BL2 56 image for the ``fip`` target. In this case, the BL2 in the TF-A will not be 57 built. 58 59- ``BL2U``: This is an optional build option which specifies the path to 60 BL2U image. In this case, the BL2U in TF-A will not be built. 61 62- ``RESET_TO_BL2``: Boolean option to enable BL2 entrypoint as the CPU reset 63 vector instead of the BL1 entrypoint. It can take the value 0 (CPU reset to BL1 64 entrypoint) or 1 (CPU reset to BL2 entrypoint). 65 The default value is 0. 66 67- ``BL2_RUNS_AT_EL3``: This is an implicit flag to denote that BL2 runs at EL3. 68 While it is explicitly set to 1 when RESET_TO_BL2 is set to 1 it can also be 69 true in a 4-world system where RESET_TO_BL2 is 0. 70 71- ``BL2_ENABLE_SP_LOAD``: Boolean option to enable loading SP packages from the 72 FIP. Automatically enabled if ``SP_LAYOUT_FILE`` is provided. 73 74- ``BL2_IN_XIP_MEM``: In some use-cases BL2 will be stored in eXecute In Place 75 (XIP) memory, like BL1. In these use-cases, it is necessary to initialize 76 the RW sections in RAM, while leaving the RO sections in place. This option 77 enable this use-case. For now, this option is only supported 78 when RESET_TO_BL2 is set to '1'. 79 80- ``BL31``: This is an optional build option which specifies the path to 81 BL31 image for the ``fip`` target. In this case, the BL31 in TF-A will not 82 be built. 83 84- ``BL31_KEY``: This option is used when ``GENERATE_COT=1``. It specifies a 85 file that contains the BL31 private key in PEM format or a PKCS11 URI. If 86 ``SAVE_KEYS=1``, only a file is accepted and it will be used to save the key. 87 88- ``BL32``: This is an optional build option which specifies the path to 89 BL32 image for the ``fip`` target. In this case, the BL32 in TF-A will not 90 be built. 91 92- ``BL32_EXTRA1``: This is an optional build option which specifies the path to 93 Trusted OS Extra1 image for the ``fip`` target. 94 95- ``BL32_EXTRA2``: This is an optional build option which specifies the path to 96 Trusted OS Extra2 image for the ``fip`` target. 97 98- ``BL32_KEY``: This option is used when ``GENERATE_COT=1``. It specifies a 99 file that contains the BL32 private key in PEM format or a PKCS11 URI. If 100 ``SAVE_KEYS=1``, only a file is accepted and it will be used to save the key. 101 102- ``RMM``: This is an optional build option used when ``ENABLE_RME`` is set. 103 It specifies the path to RMM binary for the ``fip`` target. If the RMM option 104 is not specified, TF-A builds the TRP to load and run at R-EL2. 105 106- ``BL33``: Path to BL33 image in the host file system. This is mandatory for 107 ``fip`` target in case TF-A BL2 is used. 108 109- ``BL33_KEY``: This option is used when ``GENERATE_COT=1``. It specifies a 110 file that contains the BL33 private key in PEM format or a PKCS11 URI. If 111 ``SAVE_KEYS=1``, only a file is accepted and it will be used to save the key. 112 113- ``BRANCH_PROTECTION``: Numeric value to enable ARMv8.3 Pointer Authentication 114 and ARMv8.5 Branch Target Identification support for TF-A BL images themselves. 115 If enabled, it is needed to use a compiler that supports the option 116 ``-mbranch-protection``. The value of the ``-march`` (via ``ARM_ARCH_MINOR`` 117 and ``ARM_ARCH_MAJOR``) option will control which instructions will be 118 emitted (HINT space or not). Selects the branch protection features to use: 119- 0: Default value turns off all types of branch protection (FEAT_STATE_DISABLED) 120- 1: Enables all types of branch protection features 121- 2: Return address signing to its standard level 122- 3: Extend the signing to include leaf functions 123- 4: Turn on branch target identification mechanism 124- 5: Enables all types of branch protection features, only if present in 125 hardware (FEAT_STATE_CHECK). 126 127 The table below summarizes ``BRANCH_PROTECTION`` values, GCC compilation options 128 and resulting PAuth/BTI features. 129 130 +-------+--------------+-------+-----+ 131 | Value | GCC option | PAuth | BTI | 132 +=======+==============+=======+=====+ 133 | 0 | none | N | N | 134 +-------+--------------+-------+-----+ 135 | 1 | standard | Y | Y | 136 +-------+--------------+-------+-----+ 137 | 2 | pac-ret | Y | N | 138 +-------+--------------+-------+-----+ 139 | 3 | pac-ret+leaf | Y | N | 140 +-------+--------------+-------+-----+ 141 | 4 | bti | N | Y | 142 +-------+--------------+-------+-----+ 143 | 5 | dynamic | Y | Y | 144 +-------+--------------+-------+-----+ 145 146 This option defaults to 0. 147 Note that Pointer Authentication is enabled for Non-secure world 148 irrespective of the value of this option if the CPU supports it. 149 150- ``BUILD_MESSAGE_TIMESTAMP``: String used to identify the time and date of the 151 compilation of each build. It must be set to a C string (including quotes 152 where applicable). Defaults to a string that contains the time and date of 153 the compilation. 154 155- ``BUILD_STRING``: Input string for VERSION_STRING, which allows the TF-A 156 build to be uniquely identified. Defaults to the current git commit id. 157 158- ``BUILD_BASE``: Output directory for the build. Defaults to ``./build`` 159 160- ``CFLAGS``: Extra user options appended on the compiler's command line in 161 addition to the options set by the build system. 162 163- ``COLD_BOOT_SINGLE_CPU``: This option indicates whether the platform may 164 release several CPUs out of reset. It can take either 0 (several CPUs may be 165 brought up) or 1 (only one CPU will ever be brought up during cold reset). 166 Default is 0. If the platform always brings up a single CPU, there is no 167 need to distinguish between primary and secondary CPUs and the boot path can 168 be optimised. The ``plat_is_my_cpu_primary()`` and 169 ``plat_secondary_cold_boot_setup()`` platform porting interfaces do not need 170 to be implemented in this case. 171 172- ``COT``: When Trusted Boot is enabled, selects the desired chain of trust. 173 Defaults to ``tbbr``. 174 175- ``CRASH_REPORTING``: A non-zero value enables a console dump of processor 176 register state when an unexpected exception occurs during execution of 177 BL31. This option defaults to the value of ``DEBUG`` - i.e. by default 178 this is only enabled for a debug build of the firmware. 179 180- ``CREATE_KEYS``: This option is used when ``GENERATE_COT=1``. It tells the 181 certificate generation tool to create new keys in case no valid keys are 182 present or specified. Allowed options are '0' or '1'. Default is '1'. 183 184- ``CTX_INCLUDE_AARCH32_REGS`` : Boolean option that, when set to 1, will cause 185 the AArch32 system registers to be included when saving and restoring the 186 CPU context. The option must be set to 0 for AArch64-only platforms (that 187 is on hardware that does not implement AArch32, or at least not at EL1 and 188 higher ELs). Default value is 1. 189 190- ``CTX_INCLUDE_FPREGS``: Boolean option that, when set to 1, will cause the FP 191 registers to be included when saving and restoring the CPU context. Default 192 is 0. 193 194- ``CTX_INCLUDE_MPAM_REGS``: Boolean option that, when set to 1, will cause the 195 Memory System Resource Partitioning and Monitoring (MPAM) 196 registers to be included when saving and restoring the CPU context. 197 Default is '0'. 198 199- ``CTX_INCLUDE_NEVE_REGS``: Numeric value, when set will cause the Armv8.4-NV 200 registers to be saved/restored when entering/exiting an EL2 execution 201 context. This flag can take values 0 to 2, to align with the 202 ``ENABLE_FEAT`` mechanism. Default value is 0. 203 204- ``CTX_INCLUDE_PAUTH_REGS``: Numeric value to enable the Pointer 205 Authentication for Secure world. This will cause the ARMv8.3-PAuth registers 206 to be included when saving and restoring the CPU context as part of world 207 switch. Automatically enabled when ``BRANCH_PROTECTION`` is enabled. This flag 208 can take values 0 to 2, to align with ``ENABLE_FEAT`` mechanism. Default value 209 is 0. 210 211 Note that Pointer Authentication is enabled for Non-secure world irrespective 212 of the value of this flag if the CPU supports it. Alternatively, when 213 ``BRANCH_PROTECTION`` is enabled, this flag is superseded. 214 215- ``CTX_INCLUDE_SVE_REGS``: Boolean option that, when set to 1, will cause the 216 SVE registers to be included when saving and restoring the CPU context. Note 217 that this build option requires ``ENABLE_SVE_FOR_SWD`` to be enabled. In 218 general, it is recommended to perform SVE context management in lower ELs 219 and skip in EL3 due to the additional cost of maintaining large data 220 structures to track the SVE state. Hence, the default value is 0. 221 222- ``DEBUG``: Chooses between a debug and release build. It can take either 0 223 (release) or 1 (debug) as values. 0 is the default. 224 225- ``DECRYPTION_SUPPORT``: This build flag enables the user to select the 226 authenticated decryption algorithm to be used to decrypt firmware/s during 227 boot. It accepts 2 values: ``aes_gcm`` and ``none``. The default value of 228 this flag is ``none`` to disable firmware decryption which is an optional 229 feature as per TBBR. 230 231- ``DISABLE_BIN_GENERATION``: Boolean option to disable the generation 232 of the binary image. If set to 1, then only the ELF image is built. 233 0 is the default. 234 235- ``DISABLE_MTPMU``: Numeric option to disable ``FEAT_MTPMU`` (Multi Threaded 236 PMU). ``FEAT_MTPMU`` is an optional feature available on Armv8.6 onwards. 237 This flag can take values 0 to 2, to align with the ``ENABLE_FEAT`` 238 mechanism. Default is ``0``. 239 240- ``DYN_DISABLE_AUTH``: Provides the capability to dynamically disable Trusted 241 Board Boot authentication at runtime. This option is meant to be enabled only 242 for development platforms. ``TRUSTED_BOARD_BOOT`` flag must be set if this 243 flag has to be enabled. 0 is the default. 244 245- ``E``: Boolean option to make warnings into errors. Default is 1. 246 247 When specifying higher warnings levels (``W=1`` and higher), this option 248 defaults to 0. This is done to encourage contributors to use them, as they 249 are expected to produce warnings that would otherwise fail the build. New 250 contributions are still expected to build with ``W=0`` and ``E=1`` (the 251 default). 252 253- ``EARLY_CONSOLE``: This option is used to enable early traces before default 254 console is properly setup. It introduces EARLY_* traces macros, that will 255 use the non-EARLY traces macros if the flag is enabled, or do nothing 256 otherwise. To use this feature, platforms will have to create the function 257 plat_setup_early_console(). 258 Default is 0 (disabled) 259 260- ``EL3_PAYLOAD_BASE``: This option enables booting an EL3 payload instead of 261 the normal boot flow. It must specify the entry point address of the EL3 262 payload. Please refer to the "Booting an EL3 payload" section for more 263 details. 264 265- ``ENABLE_AMU_AUXILIARY_COUNTERS``: Enables support for AMU auxiliary counters 266 (also known as group 1 counters). These are implementation-defined counters, 267 and as such require additional platform configuration. Default is 0. 268 269- ``ENABLE_ASSERTIONS``: This option controls whether or not calls to ``assert()`` 270 are compiled out. For debug builds, this option defaults to 1, and calls to 271 ``assert()`` are left in place. For release builds, this option defaults to 0 272 and calls to ``assert()`` function are compiled out. This option can be set 273 independently of ``DEBUG``. It can also be used to hide any auxiliary code 274 that is only required for the assertion and does not fit in the assertion 275 itself. 276 277- ``ENABLE_BACKTRACE``: This option controls whether to enable backtrace 278 dumps or not. It is supported in both AArch64 and AArch32. However, in 279 AArch32 the format of the frame records are not defined in the AAPCS and they 280 are defined by the implementation. This implementation of backtrace only 281 supports the format used by GCC when T32 interworking is disabled. For this 282 reason enabling this option in AArch32 will force the compiler to only 283 generate A32 code. This option is enabled by default only in AArch64 debug 284 builds, but this behaviour can be overridden in each platform's Makefile or 285 in the build command line. 286 287- ``ENABLE_FEAT_AMU``: Numeric value to enable Activity Monitor Unit 288 extensions. This flag can take the values 0 to 2, to align with the 289 ``ENABLE_FEAT`` mechanism. This is an optional architectural feature 290 available on v8.4 onwards. Some v8.2 implementations also implement an AMU 291 and this option can be used to enable this feature on those systems as well. 292 This flag can take the values 0 to 2, the default is 0. 293 294- ``ENABLE_FEAT_AMUv1p1``: Numeric value to enable the ``FEAT_AMUv1p1`` 295 extension. ``FEAT_AMUv1p1`` is an optional feature available on Arm v8.6 296 onwards. This flag can take the values 0 to 2, to align with the 297 ``ENABLE_FEAT`` mechanism. Default value is ``0``. 298 299- ``ENABLE_FEAT_CLRBHB``: Numeric value to enable the CLRBHB instruction. 300 Clear Branch History clears the branch history for the current context to 301 the extent that branch history information created before the CLRBHB instruction 302 cannot be used by code. This is an optional architectural feature available on v8.0 303 onwards and is a mandatory feature from v8.9 onwards. 304 This flag can take the values of 0 to 2, to align with the ``ENABLE_FEAT`` mechanism. 305 Default value is ``0``. 306 307- ``ENABLE_FEAT_CPA2``: Numeric value to enable the ``FEAT_CPA2`` extension. 308 It enables checked pointer arithmetic in EL3, which will result in address 309 faults in the event that a pointer arithmetic overflow error occurs. This is 310 an optional feature starting from Arm v9.4 and This flag can take values 0 to 311 2, to align with the ``ENABLE_FEAT`` mechanism. Default value is ``0``. 312 313- ``ENABLE_FEAT_CSV2_2``: Numeric value to enable the ``FEAT_CSV2_2`` 314 extension. It allows access to the SCXTNUM_EL2 (Software Context Number) 315 register during EL2 context save/restore operations. ``FEAT_CSV2_2`` is an 316 optional feature available on Arm v8.0 onwards. This flag can take values 317 0 to 2, to align with the ``ENABLE_FEAT`` mechanism. 318 Default value is ``0``. 319 320- ``ENABLE_FEAT_CSV2_3``: Numeric value to enable support for ``FEAT_CSV2_3`` 321 extension. This feature is supported in AArch64 state only and is an optional 322 feature available in Arm v8.0 implementations. 323 ``FEAT_CSV2_3`` implies the implementation of ``FEAT_CSV2_2``. 324 The flag can take values 0 to 2, to align with the ``ENABLE_FEAT`` 325 mechanism. Default value is ``0``. 326 327- ``ENABLE_FEAT_DEBUGV8P9``: Numeric value to enable ``FEAT_DEBUGV8P9`` 328 extension which allows the ability to implement more than 16 breakpoints 329 and/or watchpoints. This feature is mandatory from v8.9 and is optional 330 from v8.8. This flag can take the values of 0 to 2, to align with the 331 ``ENABLE_FEAT`` mechanism. Default value is ``0``. 332 333- ``ENABLE_FEAT_DIT``: Numeric value to enable ``FEAT_DIT`` (Data Independent 334 Timing) extension. It allows setting the ``DIT`` bit of PSTATE in EL3. 335 ``FEAT_DIT`` is a mandatory architectural feature and is enabled from v8.4 336 and upwards. This flag can take the values 0 to 2, to align with the 337 ``ENABLE_FEAT`` mechanism. Default value is ``0``. 338 339- ``ENABLE_FEAT_ECV``: Numeric value to enable support for the Enhanced Counter 340 Virtualization feature, allowing for access to the CNTPOFF_EL2 (Counter-timer 341 Physical Offset register) during EL2 to EL3 context save/restore operations. 342 Its a mandatory architectural feature and is enabled from v8.6 and upwards. 343 This flag can take the values 0 to 2, to align with the ``ENABLE_FEAT`` 344 mechanism. Default value is ``0``. 345 346- ``ENABLE_FEAT_FPMR``: Numerical value to enable support for Floating Point 347 Mode Register feature, allowing access to the FPMR register. FPMR register 348 controls the behaviors of FP8 instructions. It is an optional architectural 349 feature from v9.2 and upwards. This flag can take value of 0 to 2, to align 350 with the ``FEATURE_DETECTION`` mechanism. Default value is ``0``. 351 352- ``ENABLE_FEAT_FGT``: Numeric value to enable support for FGT (Fine Grain Traps) 353 feature allowing for access to the HDFGRTR_EL2 (Hypervisor Debug Fine-Grained 354 Read Trap Register) during EL2 to EL3 context save/restore operations. 355 Its a mandatory architectural feature and is enabled from v8.6 and upwards. 356 This flag can take the values 0 to 2, to align with the ``ENABLE_FEAT`` 357 mechanism. Default value is ``0``. 358 359- ``ENABLE_FEAT_FGT2``: Numeric value to enable support for FGT2 360 (Fine Grain Traps 2) feature allowing for access to Fine-grained trap 2 registers 361 during EL2 to EL3 context save/restore operations. 362 Its an optional architectural feature and is available from v8.8 and upwards. 363 This flag can take the values 0 to 2, to align with the ``ENABLE_FEAT`` 364 mechanism. Default value is ``0``. 365 366- ``ENABLE_FEAT_FGWTE3``: Numeric value to enable support for 367 Fine Grained Write Trap EL3 (FEAT_FGWTE3), a feature that allows EL3 to 368 restrict overwriting certain EL3 registers after boot. 369 This lockdown is established by setting individual trap bits for 370 system registers that are not expected to be overwritten after boot. 371 This feature is an optional architectural feature and is available from 372 Armv9.4 onwards. This flag can take values from 0 to 2, aligning with 373 the ``ENABLE_FEAT`` mechanism. The default value is 0. 374 375 .. note:: 376 This feature currently traps access to all EL3 registers in 377 ``FGWTE3_EL3``, except for ``MDCR_EL3``, ``MPAM3_EL3``, 378 ``TPIDR_EL3``(when ``CRASH_REPORTING=1``), and 379 ``SCTLR_EL3``(when ``HW_ASSISTED_COHERENCY=0``). 380 If additional traps need to be disabled for specific platforms, 381 please contact the Arm team on `TF-A public mailing list`_. 382 383- ``ENABLE_FEAT_HCX``: Numeric value to set the bit SCR_EL3.HXEn in EL3 to 384 allow access to HCRX_EL2 (extended hypervisor control register) from EL2 as 385 well as adding HCRX_EL2 to the EL2 context save/restore operations. Its a 386 mandatory architectural feature and is enabled from v8.7 and upwards. This 387 flag can take the values 0 to 2, to align with the ``ENABLE_FEAT`` 388 mechanism. Default value is ``0``. 389 390- ``ENABLE_FEAT_IDTE3``: Numeric value to set SCR_EL3.TID3/TID5 bits which 391 enables trapping of ID register reads by lower ELs to EL3. This allows EL3 392 to control the feature visibility to lower ELs by returning a sanitized value 393 based on current feature enablement status. Hypervisors are expected to 394 cache ID register during their boot stage. This flag can take the 395 values 0 to 2, to align with the ``ENABLE_FEAT`` mechanism. 396 Default value is ``0``. This feature is EXPERIMENTAL. 397 398 .. note:: 399 This feature traps all lower EL accesses to Group 3 and Group 5 400 ID registers to EL3. This can incur a performance impact and platforms 401 should enable them only if they have a specific need. 402 403- ``ENABLE_FEAT_MOPS``: Numeric value to enable FEAT_MOPS (Standardization 404 of memory operations) when INIT_UNUSED_NS_EL2=1. 405 This feature is mandatory from v8.8 and enabling of FEAT_MOPS does not 406 require any settings from EL3 as the controls are present in EL2 registers 407 (HCRX_EL2.{MSCEn,MCE2} and SCTLR_EL2.MSCEn) and in most configurations 408 we expect EL2 to be present. But in case of INIT_UNUSED_NS_EL2=1 , 409 EL3 should configure the EL2 registers. This flag 410 can take values 0 to 2, to align with the ``ENABLE_FEAT`` mechanism. 411 Default value is ``0``. 412 413- ``ENABLE_FEAT_MTE2``: Numeric value to enable Memory Tagging Extension2 414 if the platform wants to use this feature and MTE2 is enabled at ELX. 415 This flag can take values 0 to 2, to align with the ``ENABLE_FEAT`` 416 mechanism. Default value is ``0``. 417 418- ``ENABLE_FEAT_PAN``: Numeric value to enable the ``FEAT_PAN`` (Privileged 419 Access Never) extension. ``FEAT_PAN`` adds a bit to PSTATE, generating a 420 permission fault for any privileged data access from EL1/EL2 to virtual 421 memory address, accessible at EL0, provided (HCR_EL2.E2H=1). It is a 422 mandatory architectural feature and is enabled from v8.1 and upwards. This 423 flag can take values 0 to 2, to align with the ``ENABLE_FEAT`` 424 mechanism. Default value is ``0``. 425 426- ``ENABLE_FEAT_PAUTH_LR``: Numeric value to enable the ``FEAT_PAUTH_LR`` 427 extension. ``FEAT_PAUTH_LR`` is an optional feature available from Arm v9.4 428 onwards. This feature requires PAUTH to be enabled via the 429 ``BRANCH_PROTECTION`` flag. This flag can take the values 0 to 2, to align 430 with the ``ENABLE_FEAT`` mechanism. Default value is ``0``. 431 432- ``ENABLE_FEAT_RNG``: Numeric value to enable the ``FEAT_RNG`` extension. 433 ``FEAT_RNG`` is an optional feature available on Arm v8.5 onwards. This 434 flag can take the values 0 to 2, to align with the ``ENABLE_FEAT`` 435 mechanism. Default value is ``0``. 436 437- ``ENABLE_FEAT_RNG_TRAP``: Numeric value to enable the ``FEAT_RNG_TRAP`` 438 extension. This feature is only supported in AArch64 state. This flag can 439 take values 0 to 2, to align with the ``ENABLE_FEAT`` mechanism. 440 Default value is ``0``. ``FEAT_RNG_TRAP`` is an optional feature from 441 Armv8.5 onwards. 442 443- ``ENABLE_FEAT_SB``: Boolean option to let the TF-A code use the ``FEAT_SB`` 444 (Speculation Barrier) instruction ``FEAT_SB`` is an optional feature and 445 defaults to ``0`` for pre-Armv8.5 CPUs, but is mandatory for Armv8.5 or 446 later CPUs. It is enabled from v8.5 and upwards and if needed can be 447 overidden from platforms explicitly. 448 449- ``ENABLE_FEAT_SEL2``: Numeric value to enable the ``FEAT_SEL2`` (Secure EL2) 450 extension. ``FEAT_SEL2`` is a mandatory feature available on Arm v8.4. 451 This flag can take values 0 to 2, to align with the ``ENABLE_FEAT`` 452 mechanism. Default is ``0``. 453 454- ``ENABLE_FEAT_TWED``: Numeric value to enable the ``FEAT_TWED`` (Delayed 455 trapping of WFE Instruction) extension. ``FEAT_TWED`` is a optional feature 456 available on Arm v8.6. This flag can take values 0 to 2, to align with the 457 ``ENABLE_FEAT`` mechanism. Default is ``0``. 458 459 When ``ENABLE_FEAT_TWED`` is set to ``1``, WFE instruction trapping gets 460 delayed by the amount of value in ``TWED_DELAY``. 461 462- ``ENABLE_FEAT_VHE``: Numeric value to enable the ``FEAT_VHE`` (Virtualization 463 Host Extensions) extension. It allows access to CONTEXTIDR_EL2 register 464 during EL2 context save/restore operations.``FEAT_VHE`` is a mandatory 465 architectural feature and is enabled from v8.1 and upwards. It can take 466 values 0 to 2, to align with the ``ENABLE_FEAT`` mechanism. 467 Default value is ``0``. 468 469- ``ENABLE_FEAT_TCR2``: Numeric value to set the bit SCR_EL3.ENTCR2 in EL3 to 470 allow access to TCR2_EL2 (extended translation control) from EL2 as 471 well as adding TCR2_EL2 to the EL2 context save/restore operations. Its a 472 mandatory architectural feature and is enabled from v8.9 and upwards. This 473 flag can take the values 0 to 2, to align with the ``ENABLE_FEAT`` 474 mechanism. Default value is ``0``. 475 476- ``ENABLE_FEAT_S2PIE``: Numeric value to enable support for FEAT_S2PIE 477 at EL2 and below, and context switch relevant registers. This flag 478 can take the values 0 to 2, to align with the ``ENABLE_FEAT`` 479 mechanism. Default value is ``0``. 480 481- ``ENABLE_FEAT_S1PIE``: Numeric value to enable support for FEAT_S1PIE 482 at EL2 and below, and context switch relevant registers. This flag 483 can take the values 0 to 2, to align with the ``ENABLE_FEAT`` 484 mechanism. Default value is ``0``. 485 486- ``ENABLE_FEAT_S2POE``: Numeric value to enable support for FEAT_S2POE 487 at EL2 and below, and context switch relevant registers. This flag 488 can take the values 0 to 2, to align with the ``ENABLE_FEAT`` 489 mechanism. Default value is ``0``. 490 491- ``ENABLE_FEAT_S1POE``: Numeric value to enable support for FEAT_S1POE 492 at EL2 and below, and context switch relevant registers. This flag 493 can take the values 0 to 2, to align with the ``ENABLE_FEAT`` 494 mechanism. Default value is ``0``. 495 496- ``ENABLE_FEAT_GCS``: Numeric value to set the bit SCR_EL3.GCSEn in EL3 to 497 allow use of Guarded Control Stack from EL2 as well as adding the GCS 498 registers to the EL2 context save/restore operations. This flag can take 499 the values 0 to 2, to align with the ``ENABLE_FEAT`` mechanism. 500 Default value is ``0``. 501 502 - ``ENABLE_FEAT_GCIE``: Boolean value to enable support for the GICv5 CPU 503 interface (see ``USE_GIC_DRIVER`` for the IRI). GICv5 and GICv3 are mutually 504 exclusive, so the ``ENABLE_FEAT`` mechanism is currently not supported. 505 Default value is ``0``. 506 507- ``ENABLE_FEAT_THE``: Numeric value to enable support for FEAT_THE 508 (Translation Hardening Extension) at EL2 and below, setting the bit 509 SCR_EL3.RCWMASKEn in EL3 to allow access to RCWMASK_EL1 and RCWSMASK_EL1 510 registers and context switch them. 511 Its an optional architectural feature and is available from v8.8 and upwards. 512 This flag can take the values 0 to 2, to align with the ``ENABLE_FEAT`` 513 mechanism. Default value is ``0``. 514 515- ``ENABLE_FEAT_SCTLR2``: Numeric value to enable support for FEAT_SCTLR2 516 (Extension to SCTLR_ELx) at EL2 and below, setting the bit 517 SCR_EL3.SCTLR2En in EL3 to allow access to SCTLR2_ELx registers and 518 context switch them. This feature is OPTIONAL from Armv8.0 implementations 519 and mandatory in Armv8.9 implementations. 520 This flag can take the values 0 to 2, to align with the ``ENABLE_FEAT`` 521 mechanism. Default value is ``0``. 522 523- ``ENABLE_FEAT_D128``: Numeric value to enable support for FEAT_D128 524 at EL2 and below, setting the bit SCT_EL3.D128En in EL3 to allow access to 525 128 bit version of system registers like PAR_EL1, TTBR0_EL1, TTBR1_EL1, 526 TTBR0_EL2, TTBR1_EL2, TTBR0_EL12, TTBR1_EL12 , VTTBR_EL2, RCWMASK_EL1, and 527 RCWSMASK_EL1. Its an optional architectural feature and is available from 528 9.3 and upwards. 529 This flag can take the values 0 to 2, to align with the ``ENABLE_FEAT`` 530 mechanism. Default value is ``0``. 531 532- ``ENABLE_LTO``: Boolean option to enable Link Time Optimization (LTO) 533 support. This option is currently only supported for AArch64. On GCC it only 534 applies to TF-A proper, and not its libraries. If LTO on libraries (except 535 the libc) is desired a platform can pass `-flto -ffat-lto-objects` as long as 536 GCC >= 14 is in use. Default is 0. 537 538- ``ENABLE_FEAT_MPAM``: Numeric value to enable lower ELs to use MPAM 539 feature. MPAM is an optional Armv8.4 extension that enables various memory 540 system components and resources to define partitions; software running at 541 various ELs can assign themselves to desired partition to control their 542 performance aspects. 543 544 This flag can take values 0 to 2, to align with the ``ENABLE_FEAT`` 545 mechanism. When this option is set to ``1`` or ``2``, EL3 allows lower ELs to 546 access their own MPAM registers without trapping into EL3. This option 547 doesn't make use of partitioning in EL3, however. Platform initialisation 548 code should configure and use partitions in EL3 as required. This option 549 defaults to ``2`` since MPAM is enabled by default for NS world only. 550 The flag is automatically disabled when the target 551 architecture is AArch32. 552 553- ``ENABLE_FEAT_MPAM_PE_BW_CTRL``: This option enables Armv9.3 MPAM 554 PE-side bandwidth controls and disables traps to EL3/EL2 (when 555 ``INIT_UNUSED_NS_EL2`` = 1). The flag accepts values from 0 to 2, in 556 line with the ``ENABLE_FEAT`` mechanism, and defaults to ``0``. 557 558- ``ENABLE_FEAT_LS64_ACCDATA``: Numeric value to enable access and save and 559 restore the ACCDATA_EL1 system register, at EL2 and below. This flag can 560 take the values 0 to 2, to align with the ``ENABLE_FEAT`` mechanism. 561 Default value is ``0``. 562 563- ``ENABLE_FEAT_AIE``: Numeric value to enable access to the (A)MAIR2 system 564 registers from non-secure world. This flag can take the values 0 to 2, to 565 align with the ``ENABLE_FEAT`` mechanism. 566 Default value is ``0``. 567 568- ``ENABLE_FEAT_PFAR``: Numeric value to enable access to the PFAR system 569 registers from non-secure world. This flag can take the values 0 to 2, to 570 align with the ``ENABLE_FEAT`` mechanism. 571 Default value is ``0``. 572 573- ``ENABLE_MPMM``: Boolean option to enable support for the Maximum Power 574 Mitigation Mechanism supported by certain Arm cores, which allows the SoC 575 firmware to detect and limit high activity events to assist in SoC processor 576 power domain dynamic power budgeting and limit the triggering of whole-rail 577 (i.e. clock chopping) responses to overcurrent conditions. Defaults to ``0``. 578 579- ``ENABLE_PIE``: Boolean option to enable Position Independent Executable(PIE) 580 support within generic code in TF-A. This option is currently only supported 581 in BL2, BL31, and BL32 (TSP) for AARCH64 binaries, and 582 in BL32 (SP_min) for AARCH32. Default is 0. 583 584- ``ENABLE_PMF``: Boolean option to enable support for optional Performance 585 Measurement Framework(PMF). Default is 0. 586 587- ``ENABLE_PSCI_STAT``: Boolean option to enable support for optional PSCI 588 functions ``PSCI_STAT_RESIDENCY`` and ``PSCI_STAT_COUNT``. Default is 0. 589 In the absence of an alternate stat collection backend, ``ENABLE_PMF`` must 590 be enabled. If ``ENABLE_PMF`` is set, the residency statistics are tracked in 591 software. 592 593- ``ENABLE_RUNTIME_INSTRUMENTATION``: Boolean option to enable runtime 594 instrumentation which injects timestamp collection points into TF-A to 595 allow runtime performance to be measured. Currently, only PSCI is 596 instrumented. Enabling this option enables the ``ENABLE_PMF`` build option 597 as well. Default is 0. 598 599- ``ENABLE_SPE_FOR_NS`` : Numeric value to enable Statistical Profiling 600 extensions. This is an optional architectural feature for AArch64. 601 This flag can take the values 0 to 2, to align with the ``ENABLE_FEAT`` 602 mechanism. The default is 2 but is automatically disabled when the target 603 architecture is AArch32. 604 605- ``ENABLE_SVE_FOR_NS``: Numeric value to enable Scalable Vector Extension 606 (SVE) for the Non-secure world only. SVE is an optional architectural feature 607 for AArch64. This flag can take the values 0 to 2, to align with the 608 ``ENABLE_FEAT`` mechanism. At this time, this build option cannot be used on 609 systems that have SPM_MM enabled. The default value is 2. 610 611 Note that when SVE is enabled for the Non-secure world, access 612 to SVE, SIMD and floating-point functionality from the Secure world is 613 independently controlled by build option ``ENABLE_SVE_FOR_SWD``. When enabling 614 ``CTX_INCLUDE_FPREGS`` and ``ENABLE_SVE_FOR_NS`` together, it is mandatory to 615 enable ``CTX_INCLUDE_SVE_REGS``. This is to avoid corruption of the Non-secure 616 world data in the Z-registers which are aliased by the SIMD and FP registers. 617 618- ``ENABLE_SVE_FOR_SWD``: Boolean option to enable SVE and FPU/SIMD functionality 619 for the Secure world. SVE is an optional architectural feature for AArch64. 620 The default is 0 and it is automatically disabled when the target architecture 621 is AArch32. 622 623 .. note:: 624 This build flag requires ``ENABLE_SVE_FOR_NS`` to be enabled. When enabling 625 ``ENABLE_SVE_FOR_SWD``, a developer must carefully consider whether 626 ``CTX_INCLUDE_SVE_REGS`` is also needed. 627 628- ``ENABLE_STACK_PROTECTOR``: String option to enable the stack protection 629 checks in GCC. Allowed values are "all", "strong", "default" and "none". The 630 default value is set to "none". "strong" is the recommended stack protection 631 level if this feature is desired. "none" disables the stack protection. For 632 all values other than "none", the ``plat_get_stack_protector_canary()`` 633 platform hook needs to be implemented. The value is passed as the last 634 component of the option ``-fstack-protector-$ENABLE_STACK_PROTECTOR``. 635 636- ``ENABLE_ERRATA_ALL``: This option is used only for testing purposes, Boolean 637 option to enable the workarounds for all errata that TF-A implements. Normally 638 they should be explicitly enabled depending on each platform's needs. Not 639 recommended for release builds. This option is default set to 0. 640 641- ``ENCRYPT_BL31``: Binary flag to enable encryption of BL31 firmware. This 642 flag depends on ``DECRYPTION_SUPPORT`` build flag. 643 644- ``ENCRYPT_BL32``: Binary flag to enable encryption of Secure BL32 payload. 645 This flag depends on ``DECRYPTION_SUPPORT`` build flag. 646 647- ``ENC_KEY``: A 32-byte (256-bit) symmetric key in hex string format. It could 648 either be SSK or BSSK depending on ``FW_ENC_STATUS`` flag. This value depends 649 on ``DECRYPTION_SUPPORT`` build flag. 650 651- ``ENC_NONCE``: A 12-byte (96-bit) encryption nonce or Initialization Vector 652 (IV) in hex string format. This value depends on ``DECRYPTION_SUPPORT`` 653 build flag. 654 655- ``ERROR_DEPRECATED``: This option decides whether to treat the usage of 656 deprecated platform APIs, helper functions or drivers within Trusted 657 Firmware as error. It can take the value 1 (flag the use of deprecated 658 APIs as error) or 0. The default is 0. 659 660- ``ETHOSN_NPU_DRIVER``: boolean option to enable a SiP service that can 661 configure an Arm® Ethos™-N NPU. To use this service the target platform's 662 ``HW_CONFIG`` must include the device tree nodes for the NPU. Currently, only 663 the Arm Juno platform has this included in its ``HW_CONFIG`` and the platform 664 only loads the ``HW_CONFIG`` in AArch64 builds. Default is 0. 665 666- ``ETHOSN_NPU_TZMP1``: boolean option to enable TZMP1 support for the 667 Arm® Ethos™-N NPU. Requires ``ETHOSN_NPU_DRIVER`` and 668 ``TRUSTED_BOARD_BOOT`` to be enabled. 669 670- ``ETHOSN_NPU_FW``: location of the NPU firmware binary 671 (```ethosn.bin```). This firmware image will be included in the FIP and 672 loaded at runtime. 673 674- ``EL3_EXCEPTION_HANDLING``: When set to ``1``, enable handling of exceptions 675 targeted at EL3. When set ``0`` (default), no exceptions are expected or 676 handled at EL3, and a panic will result. The exception to this rule is when 677 ``SPMD_SPM_AT_SEL2`` is set to ``1``, in which case, only exceptions 678 occuring during normal world execution, are trapped to EL3. Any exception 679 trapped during secure world execution are trapped to the SPMC. This is 680 supported only for AArch64 builds. 681 682- ``EVENT_LOG_LEVEL``: Chooses the log level to use for Measured Boot when 683 ``MEASURED_BOOT`` is enabled. For a list of valid values, see ``LOG_LEVEL``. 684 Default value is 40 (LOG_LEVEL_INFO). 685 686- ``FAULT_INJECTION_SUPPORT``: ARMv8.4 extensions introduced support for fault 687 injection from lower ELs, and this build option enables lower ELs to use 688 Error Records accessed via System Registers to inject faults. This is 689 applicable only to AArch64 builds. 690 691 This feature is intended for testing purposes only, and is advisable to keep 692 disabled for production images. 693 694- ``FIP_NAME``: This is an optional build option which specifies the FIP 695 filename for the ``fip`` target. Default is ``fip.bin``. 696 697- ``FWU_FIP_NAME``: This is an optional build option which specifies the FWU 698 FIP filename for the ``fwu_fip`` target. Default is ``fwu_fip.bin``. 699 700- ``FW_ENC_STATUS``: Top level firmware's encryption numeric flag, values: 701 702 :: 703 704 0: Encryption is done with Secret Symmetric Key (SSK) which is common 705 for a class of devices. 706 1: Encryption is done with Binding Secret Symmetric Key (BSSK) which is 707 unique per device. 708 709 This flag depends on ``DECRYPTION_SUPPORT`` build flag. 710 711- ``GENERATE_COT``: Boolean flag used to build and execute the ``cert_create`` 712 tool to create certificates as per the Chain of Trust described in 713 :ref:`Trusted Board Boot`. The build system then calls ``fiptool`` to 714 include the certificates in the FIP and FWU_FIP. Default value is '0'. 715 716 Specify both ``TRUSTED_BOARD_BOOT=1`` and ``GENERATE_COT=1`` to include support 717 for the Trusted Board Boot feature in the BL1 and BL2 images, to generate 718 the corresponding certificates, and to include those certificates in the 719 FIP and FWU_FIP. 720 721 Note that if ``TRUSTED_BOARD_BOOT=0`` and ``GENERATE_COT=1``, the BL1 and BL2 722 images will not include support for Trusted Board Boot. The FIP will still 723 include the corresponding certificates. This FIP can be used to verify the 724 Chain of Trust on the host machine through other mechanisms. 725 726 Note that if ``TRUSTED_BOARD_BOOT=1`` and ``GENERATE_COT=0``, the BL1 and BL2 727 images will include support for Trusted Board Boot, but the FIP and FWU_FIP 728 will not include the corresponding certificates, causing a boot failure. 729 730- ``GICV2_G0_FOR_EL3``: Unlike GICv3, the GICv2 architecture doesn't have 731 inherent support for specific EL3 type interrupts. Setting this build option 732 to ``1`` assumes GICv2 *Group 0* interrupts are expected to target EL3, both 733 by :ref:`platform abstraction layer<platform Interrupt Controller API>` and 734 :ref:`Interrupt Management Framework<Interrupt Management Framework>`. 735 This allows GICv2 platforms to enable features requiring EL3 interrupt type. 736 This also means that all GICv2 Group 0 interrupts are delivered to EL3, and 737 the Secure Payload interrupts needs to be synchronously handed over to Secure 738 EL1 for handling. The default value of this option is ``0``, which means the 739 Group 0 interrupts are assumed to be handled by Secure EL1. 740 741- ``HANDLE_EA_EL3_FIRST_NS``: When set to ``1``, External Aborts and SError 742 Interrupts, resulting from errors in NS world, will be always trapped in 743 EL3 i.e. in BL31 at runtime. When set to ``0`` (default), these exceptions 744 will be trapped in the current exception level (or in EL1 if the current 745 exception level is EL0). 746 747- ``HW_ASSISTED_COHERENCY``: On most Arm systems to-date, platform-specific 748 software operations are required for CPUs to enter and exit coherency. 749 However, newer systems exist where CPUs' entry to and exit from coherency 750 is managed in hardware. Such systems require software to only initiate these 751 operations, and the rest is managed in hardware, minimizing active software 752 management. In such systems, this boolean option enables TF-A to carry out 753 build and run-time optimizations during boot and power management operations. 754 This option defaults to 0 and if it is enabled, then it implies 755 ``WARMBOOT_ENABLE_DCACHE_EARLY`` is also enabled. 756 757 If this flag is disabled while the platform which TF-A is compiled for 758 includes cores that manage coherency in hardware, then a compilation error is 759 generated. This is based on the fact that a system cannot have, at the same 760 time, cores that manage coherency in hardware and cores that don't. In other 761 words, a platform cannot have, at the same time, cores that require 762 ``HW_ASSISTED_COHERENCY=1`` and cores that require 763 ``HW_ASSISTED_COHERENCY=0``. 764 765 Note that, when ``HW_ASSISTED_COHERENCY`` is enabled, version 2 of 766 translation library (xlat tables v2) must be used; version 1 of translation 767 library is not supported. 768 769- ``IMPDEF_SYSREG_TRAP``: Numeric value to enable the handling traps for 770 implementation defined system register accesses from lower ELs. Default 771 value is ``0``. 772 773- ``INVERTED_MEMMAP``: memmap tool print by default lower addresses at the 774 bottom, higher addresses at the top. This build flag can be set to '1' to 775 invert this behavior. Lower addresses will be printed at the top and higher 776 addresses at the bottom. 777 778- ``INIT_UNUSED_NS_EL2``: This build flag guards code that disables EL2 779 safely in scenario where NS-EL2 is present but unused. This flag is set to 0 780 by default. Platforms without NS-EL2 in use must enable this flag. 781 782- ``KEY_ALG``: This build flag enables the user to select the algorithm to be 783 used for generating the PKCS keys and subsequent signing of the certificate. 784 It accepts 5 values: ``rsa``, ``rsa_1_5``, ``ecdsa``, ``ecdsa-brainpool-regular`` 785 and ``ecdsa-brainpool-twisted``. The option ``rsa_1_5`` is the legacy PKCS#1 786 RSA 1.5 algorithm which is not TBBR compliant and is retained only for 787 compatibility. The default value of this flag is ``rsa`` which is the TBBR 788 compliant PKCS#1 RSA 2.1 scheme. 789 790- ``KEY_SIZE``: This build flag enables the user to select the key size for 791 the algorithm specified by ``KEY_ALG``. The valid values for ``KEY_SIZE`` 792 depend on the chosen algorithm and the cryptographic module. 793 794 +---------------------------+------------------------------------+ 795 | KEY_ALG | Possible key sizes | 796 +===========================+====================================+ 797 | rsa | 1024 , 2048 (default), 3072, 4096 | 798 +---------------------------+------------------------------------+ 799 | ecdsa | 256 (default), 384 | 800 +---------------------------+------------------------------------+ 801 | ecdsa-brainpool-regular | 256 (default) | 802 +---------------------------+------------------------------------+ 803 | ecdsa-brainpool-twisted | 256 (default) | 804 +---------------------------+------------------------------------+ 805 806- ``HASH_ALG``: This build flag enables the user to select the secure hash 807 algorithm. It accepts 3 values: ``sha256``, ``sha384`` and ``sha512``. 808 The default value of this flag is ``sha256``. 809 810- ``HW_CONFIG_BASE``: This option specifies the location in memory where the DTB 811 should either be loaded by BL2 or can be found by later stages. 812 813- ``LDFLAGS``: Extra user options appended to the linkers' command line in 814 addition to the one set by the build system. 815 816- ``LOG_LEVEL``: Chooses the log level, which controls the amount of console log 817 output compiled into the build. This should be one of the following: 818 819 :: 820 821 0 (LOG_LEVEL_NONE) 822 10 (LOG_LEVEL_ERROR) 823 20 (LOG_LEVEL_NOTICE) 824 30 (LOG_LEVEL_WARNING) 825 40 (LOG_LEVEL_INFO) 826 50 (LOG_LEVEL_VERBOSE) 827 828 All log output up to and including the selected log level is compiled into 829 the build. The default value is 40 in debug builds and 20 in release builds. 830 831- ``MEASURED_BOOT``: Boolean flag to include support for the Measured Boot 832 feature. This flag can be enabled with ``TRUSTED_BOARD_BOOT`` in order to 833 provide trust that the code taking the measurements and recording them has 834 not been tampered with. 835 836 This option defaults to 0. 837 838- ``DISCRETE_TPM``: Boolean flag to include support for a Discrete TPM. 839 840 This option defaults to 0. 841 842- ``TPM_INTERFACE``: When ``DISCRETE_TPM=1``, this is a required flag to 843 select the TPM interface. Currently only one interface is supported: 844 845 :: 846 847 FIFO_SPI 848 849- ``MBOOT_TPM_HASH_ALG``: Build flag to select the TPM hash algorithm used during 850 Measured Boot. Currently only accepts ``sha256`` as a valid algorithm. 851 852- ``MARCH_DIRECTIVE``: used to pass a -march option from the platform build 853 options to the compiler. An example usage: 854 855 .. code:: make 856 857 MARCH_DIRECTIVE := -march=armv8.5-a 858 859- ``HARDEN_SLS``: used to pass -mharden-sls=all from the TF-A build 860 options to the compiler currently supporting only of the options. 861 GCC documentation: 862 https://gcc.gnu.org/onlinedocs/gcc/AArch64-Options.html#index-mharden-sls 863 864 An example usage: 865 866 .. code:: make 867 868 HARDEN_SLS := 1 869 870 This option defaults to 0. 871 872- ``NON_TRUSTED_WORLD_KEY``: This option is used when ``GENERATE_COT=1``. It 873 specifies a file that contains the Non-Trusted World private key in PEM 874 format or a PKCS11 URI. If ``SAVE_KEYS=1``, only a file is accepted and it 875 will be used to save the key. 876 877- ``NS_BL2U``: Path to NS_BL2U image in the host file system. This image is 878 optional. It is only needed if the platform makefile specifies that it 879 is required in order to build the ``fwu_fip`` target. 880 881- ``NS_TIMER_SWITCH``: (deprecated) Enable save and restore for non-secure 882 timer register contents upon world switch. It can take either 0 (don't save 883 and restore) or 1 (do save and restore). 0 is the default. An SPD may set 884 this to 1 if it wants the timer registers to be saved and restored. This 885 option has been deprecated since it breaks Linux preemption model. 886 887- ``OVERRIDE_LIBC``: This option allows platforms to override the default libc 888 for the BL image. It can be either 0 (include) or 1 (remove). The default 889 value is 0. 890 891- ``PL011_GENERIC_UART``: Boolean option to indicate the PL011 driver that 892 the underlying hardware is not a full PL011 UART but a minimally compliant 893 generic UART, which is a subset of the PL011. The driver will not access 894 any register that is not part of the SBSA generic UART specification. 895 Default value is 0 (a full PL011 compliant UART is present). 896 897- ``PLAT``: Choose a platform to build TF-A for. The chosen platform name 898 must be subdirectory of any depth under ``plat/``, and must contain a 899 platform makefile named ``platform.mk``. For example, to build TF-A for the 900 Arm Juno board, select PLAT=juno. 901 902- ``PLATFORM_REPORT_CTX_MEM_USE``: Reports the context memory allocated for 903 each core as well as the global context. The data includes the memory used 904 by each world and each privileged exception level. This build option is 905 applicable only for ``ARCH=aarch64`` builds. The default value is 0. 906 907- ``PLAT_EXTRA_LD_SCRIPT``: Allows the platform to include a custom LD script 908 snippet for any custom sections that cannot be expressed otherwise. Defaults 909 to 0. 910 911- ``PRELOADED_BL33_BASE``: This option enables booting a preloaded BL33 image 912 instead of the normal boot flow. When defined, it must specify the entry 913 point address for the preloaded BL33 image. This option is incompatible with 914 ``EL3_PAYLOAD_BASE``. If both are defined, ``EL3_PAYLOAD_BASE`` has priority 915 over ``PRELOADED_BL33_BASE``. 916 917- ``PRESERVE_DSU_PMU_REGS``: This options when enabled allows the platform to 918 save/restore the DynamIQ Shared Unit's(DSU) Performance Monitoring Unit(PMU) 919 registers when the cluster goes through a power cycle. This is disabled by 920 default and platforms that require this feature have to enable them. 921 922- ``PROGRAMMABLE_RESET_ADDRESS``: This option indicates whether the reset 923 vector address can be programmed or is fixed on the platform. It can take 924 either 0 (fixed) or 1 (programmable). Default is 0. If the platform has a 925 programmable reset address, it is expected that a CPU will start executing 926 code directly at the right address, both on a cold and warm reset. In this 927 case, there is no need to identify the entrypoint on boot and the boot path 928 can be optimised. The ``plat_get_my_entrypoint()`` platform porting interface 929 does not need to be implemented in this case. 930 931- ``PSCI_EXTENDED_STATE_ID``: As per PSCI1.0 Specification, there are 2 formats 932 possible for the PSCI power-state parameter: original and extended State-ID 933 formats. This flag if set to 1, configures the generic PSCI layer to use the 934 extended format. The default value of this flag is 0, which means by default 935 the original power-state format is used by the PSCI implementation. This flag 936 should be specified by the platform makefile and it governs the return value 937 of PSCI_FEATURES API for CPU_SUSPEND smc function id. When this option is 938 enabled on Arm platforms, the option ``ARM_RECOM_STATE_ID_ENC`` needs to be 939 set to 1 as well. 940 941- ``PSCI_OS_INIT_MODE``: Boolean flag to enable support for optional PSCI 942 OS-initiated mode. This option defaults to 0. 943 944- ``ARCH_FEATURE_AVAILABILITY``: Boolean flag to enable support for the 945 optional SMCCC_ARCH_FEATURE_AVAILABILITY call. This option implicitly 946 interacts with IMPDEF_SYSREG_TRAP and software emulation. This option 947 defaults to 0. 948 949- ``ENABLE_FEAT_RAS``: Boolean flag to enable Armv8.2 RAS features. RAS features 950 are an optional extension for pre-Armv8.2 CPUs, but are mandatory for Armv8.2 951 or later CPUs. This flag can take the values 0 or 1. The default value is 0. 952 NOTE: This flag enables use of IESB capability to reduce entry latency into 953 EL3 even when RAS error handling is not performed on the platform. Hence this 954 flag is recommended to be turned on Armv8.2 and later CPUs. 955 956- ``RESET_TO_BL31``: Enable BL31 entrypoint as the CPU reset vector instead 957 of the BL1 entrypoint. It can take the value 0 (CPU reset to BL1 958 entrypoint) or 1 (CPU reset to BL31 entrypoint). 959 The default value is 0. 960 961- ``RESET_TO_SP_MIN``: SP_MIN is the minimal AArch32 Secure Payload provided 962 in TF-A. This flag configures SP_MIN entrypoint as the CPU reset vector 963 instead of the BL1 entrypoint. It can take the value 0 (CPU reset to BL1 964 entrypoint) or 1 (CPU reset to SP_MIN entrypoint). The default value is 0. 965 966- ``RME_GPT_BITLOCK_BLOCK``: This defines the block size (in number of 512MB 967- blocks) covered by a single bit of the bitlock structure during RME GPT 968- operations. The lower the block size, the better opportunity for 969- parallelising GPT operations but at the cost of more bits being needed 970- for the bitlock structure. This numeric parameter can take the values 971- from 0 to 512 and must be a power of 2. The value of 0 is special and 972- and it chooses a single spinlock for all GPT L1 table entries. Default 973- value is 1 which corresponds to block size of 512MB per bit of bitlock 974- structure. 975 976- ``RME_GPT_MAX_BLOCK``: Numeric value in MB to define the maximum size of 977 supported contiguous blocks in GPT Library. This parameter can take the 978 values 0, 2, 32 and 512. Setting this value to 0 disables use of Contigious 979 descriptors. Default value is 512. 980 981- ``ROT_KEY``: This option is used when ``GENERATE_COT=1``. It specifies a 982 file that contains the ROT private key in PEM format or a PKCS11 URI and 983 enforces public key hash generation. If ``SAVE_KEYS=1``, only a file is 984 accepted and it will be used to save the key. 985 986- ``SAVE_KEYS``: This option is used when ``GENERATE_COT=1``. It tells the 987 certificate generation tool to save the keys used to establish the Chain of 988 Trust. Allowed options are '0' or '1'. Default is '0' (do not save). 989 990- ``SCP_BL2``: Path to SCP_BL2 image in the host file system. This image is optional. 991 If a SCP_BL2 image is present then this option must be passed for the ``fip`` 992 target. 993 994- ``SCP_BL2_KEY``: This option is used when ``GENERATE_COT=1``. It specifies a 995 file that contains the SCP_BL2 private key in PEM format or a PKCS11 URI. 996 If ``SAVE_KEYS=1``, only a file is accepted and it will be used to save the key. 997 998- ``SCP_BL2U``: Path to SCP_BL2U image in the host file system. This image is 999 optional. It is only needed if the platform makefile specifies that it 1000 is required in order to build the ``fwu_fip`` target. 1001 1002- ``SDEI_SUPPORT``: Setting this to ``1`` enables support for Software 1003 Delegated Exception Interface to BL31 image. This defaults to ``0``. 1004 1005 When set to ``1``, the build option ``EL3_EXCEPTION_HANDLING`` must also be 1006 set to ``1``. 1007 1008- ``SEPARATE_CODE_AND_RODATA``: Whether code and read-only data should be 1009 isolated on separate memory pages. This is a trade-off between security and 1010 memory usage. See "Isolating code and read-only data on separate memory 1011 pages" section in :ref:`Firmware Design`. This flag is disabled by default 1012 and affects all BL images. 1013 1014- ``SEPARATE_NOBITS_REGION``: Setting this option to ``1`` allows the NOBITS 1015 sections of BL31 (.bss, stacks, page tables, and coherent memory) to be 1016 allocated in RAM discontiguous from the loaded firmware image. When set, the 1017 platform is expected to provide definitions for ``BL31_NOBITS_BASE`` and 1018 ``BL31_NOBITS_LIMIT``. When the option is ``0`` (the default), NOBITS 1019 sections are placed in RAM immediately following the loaded firmware image. 1020 1021- ``SEPARATE_BL2_NOLOAD_REGION``: Setting this option to ``1`` allows the 1022 NOLOAD sections of BL2 (.bss, stacks, page tables) to be allocated in RAM 1023 discontiguous from loaded firmware images. When set, the platform need to 1024 provide definitions of ``BL2_NOLOAD_START`` and ``BL2_NOLOAD_LIMIT``. This 1025 flag is disabled by default and NOLOAD sections are placed in RAM immediately 1026 following the loaded firmware image. 1027 1028- ``SEPARATE_BL2_FIP``: This option enables the separation of the BL2 FIP image 1029 from the main FIP image. When this option is enabled, the BL2 FIP image is built 1030 as a separate FIP image. The default value is 0. 1031 1032- ``SEPARATE_SIMD_SECTION``: Setting this option to ``1`` allows the SIMD context 1033 data structures to be put in a dedicated memory region as decided by platform 1034 integrator. Default value is ``0`` which means the SIMD context is put in BSS 1035 section of EL3 firmware. 1036 1037- ``SMC_PCI_SUPPORT``: This option allows platforms to handle PCI configuration 1038 access requests via a standard SMCCC defined in `DEN0115`_. When combined with 1039 UEFI+ACPI this can provide a certain amount of OS forward compatibility 1040 with newer platforms that aren't ECAM compliant. 1041 1042- ``SPD``: Choose a Secure Payload Dispatcher component to be built into TF-A. 1043 This build option is only valid if ``ARCH=aarch64``. The value should be 1044 the path to the directory containing the SPD source, relative to 1045 ``services/spd/``; the directory is expected to contain a makefile called 1046 ``<spd-value>.mk``. The SPM Dispatcher standard service is located in 1047 services/std_svc/spmd and enabled by ``SPD=spmd``. The SPM Dispatcher 1048 cannot be enabled when the ``SPM_MM`` option is enabled. 1049 1050- ``SPIN_ON_BL1_EXIT``: This option introduces an infinite loop in BL1. It can 1051 take either 0 (no loop) or 1 (add a loop). 0 is the default. This loop stops 1052 execution in BL1 just before handing over to BL31. At this point, all 1053 firmware images have been loaded in memory, and the MMU and caches are 1054 turned off. Refer to the "Debugging options" section for more details. 1055 1056- ``SPMC_AT_EL3`` : This boolean option is used jointly with the SPM 1057 Dispatcher option (``SPD=spmd``). When enabled (1) it indicates the SPMC 1058 component runs at the EL3 exception level. The default value is ``0`` ( 1059 disabled). This configuration supports pre-Armv8.4 platforms (aka not 1060 implementing the ``FEAT_SEL2`` extension). 1061 1062- ``SPMC_AT_EL3_SEL0_SP`` : Boolean option to enable SEL0 SP load support when 1063 ``SPMC_AT_EL3`` is enabled. The default value if ``0`` (disabled). This 1064 option cannot be enabled (``1``) when (``SPMC_AT_EL3``) is disabled. 1065 1066- ``SPMC_OPTEE`` : This boolean option is used jointly with the SPM 1067 Dispatcher option (``SPD=spmd``) and with ``SPMD_SPM_AT_SEL2=0`` to 1068 indicate that the SPMC at S-EL1 is OP-TEE and an OP-TEE specific loading 1069 mechanism should be used. 1070 1071- ``SPMD_SPM_AT_SEL2`` : This boolean option is used jointly with the SPM 1072 Dispatcher option (``SPD=spmd``). When enabled (1) it indicates the SPMC 1073 component runs at the S-EL2 exception level provided by the ``FEAT_SEL2`` 1074 extension. This is the default when enabling the SPM Dispatcher. When 1075 disabled (0) it indicates the SPMC component runs at the S-EL1 execution 1076 state or at EL3 if ``SPMC_AT_EL3`` is enabled. The latter configurations 1077 support pre-Armv8.4 platforms (aka not implementing the ``FEAT_SEL2`` 1078 extension). 1079 1080- ``SPM_MM`` : Boolean option to enable the Management Mode (MM)-based Secure 1081 Partition Manager (SPM) implementation. The default value is ``0`` 1082 (disabled). This option cannot be enabled (``1``) when SPM Dispatcher is 1083 enabled (``SPD=spmd``). 1084 1085- ``SP_LAYOUT_FILE``: Platform provided path to JSON file containing the 1086 description of secure partitions. The build system will parse this file and 1087 package all secure partition blobs into the FIP. This file is not 1088 necessarily part of TF-A tree. Only available when ``SPD=spmd``. 1089 1090- ``SP_MIN_WITH_SECURE_FIQ``: Boolean flag to indicate the SP_MIN handles 1091 secure interrupts (caught through the FIQ line). Platforms can enable 1092 this directive if they need to handle such interruption. When enabled, 1093 the FIQ are handled in monitor mode and non secure world is not allowed 1094 to mask these events. Platforms that enable FIQ handling in SP_MIN shall 1095 implement the api ``sp_min_plat_fiq_handler()``. The default value is 0. 1096 1097- ``SVE_VECTOR_LEN``: SVE vector length to configure in ZCR_EL3. 1098 Platforms can configure this if they need to lower the hardware 1099 limit, for example due to asymmetric configuration or limitations of 1100 software run at lower ELs. The default is the architectural maximum 1101 of 2048 which should be suitable for most configurations, the 1102 hardware will limit the effective VL to the maximum physically supported 1103 VL. 1104 1105- ``TRNG_SUPPORT``: Setting this to ``1`` enables support for True 1106 Random Number Generator Interface to BL31 image. This defaults to ``0``. 1107 1108- ``TRUSTED_BOARD_BOOT``: Boolean flag to include support for the Trusted Board 1109 Boot feature. When set to '1', BL1 and BL2 images include support to load 1110 and verify the certificates and images in a FIP, and BL1 includes support 1111 for the Firmware Update. The default value is '0'. Generation and inclusion 1112 of certificates in the FIP and FWU_FIP depends upon the value of the 1113 ``GENERATE_COT`` option. 1114 1115 .. warning:: 1116 This option depends on ``CREATE_KEYS`` to be enabled. If the keys 1117 already exist in disk, they will be overwritten without further notice. 1118 1119- ``TRUSTED_WORLD_KEY``: This option is used when ``GENERATE_COT=1``. It 1120 specifies a file that contains the Trusted World private key in PEM 1121 format or a PKCS11 URI. If ``SAVE_KEYS=1``, only a file is accepted and 1122 it will be used to save the key. 1123 1124- ``TSP_INIT_ASYNC``: Choose BL32 initialization method as asynchronous or 1125 synchronous, (see "Initializing a BL32 Image" section in 1126 :ref:`Firmware Design`). It can take the value 0 (BL32 is initialized using 1127 synchronous method) or 1 (BL32 is initialized using asynchronous method). 1128 Default is 0. 1129 1130- ``TSP_NS_INTR_ASYNC_PREEMPT``: A non zero value enables the interrupt 1131 routing model which routes non-secure interrupts asynchronously from TSP 1132 to EL3 causing immediate preemption of TSP. The EL3 is responsible 1133 for saving and restoring the TSP context in this routing model. The 1134 default routing model (when the value is 0) is to route non-secure 1135 interrupts to TSP allowing it to save its context and hand over 1136 synchronously to EL3 via an SMC. 1137 1138 .. note:: 1139 When ``EL3_EXCEPTION_HANDLING`` is ``1``, ``TSP_NS_INTR_ASYNC_PREEMPT`` 1140 must also be set to ``1``. 1141 1142- ``TS_SP_FW_CONFIG``: DTC build flag to include Trusted Services (Crypto and 1143 internal-trusted-storage) as SP in tb_fw_config device tree. 1144 1145- ``TWED_DELAY``: Numeric value to be set in order to delay the trapping of 1146 WFE instruction. ``ENABLE_FEAT_TWED`` build option must be enabled to set 1147 this delay. It can take values in the range (0-15). Default value is ``0`` 1148 and based on this value, 2^(TWED_DELAY + 8) cycles will be delayed. 1149 Platforms need to explicitly update this value based on their requirements. 1150 1151- ``USE_ARM_LINK``: This flag determines whether to enable support for ARM 1152 linker. When the ``LINKER`` build variable points to the armlink linker, 1153 this flag is enabled automatically. To enable support for armlink, platforms 1154 will have to provide a scatter file for the BL image. Currently, Tegra 1155 platforms use the armlink support to compile BL3-1 images. 1156 1157- ``USE_COHERENT_MEM``: This flag determines whether to include the coherent 1158 memory region in the BL memory map or not (see "Use of Coherent memory in 1159 TF-A" section in :ref:`Firmware Design`). It can take the value 1 1160 (Coherent memory region is included) or 0 (Coherent memory region is 1161 excluded). Default is 1. 1162 1163- ``USE_KERNEL_DT_CONVENTION``: When this option is enabled, the hardware 1164 device tree is passed to BL33 using register x0, aligning with the expectations 1165 of the Linux kernel on Arm platforms. If this option is disabled, a different 1166 register, typically x1, may be used instead. This build option is 1167 not necessary when firmware handoff is active (that is, when TRANSFER_LIST=1 1168 is set), and it will be removed once all platforms have transitioned to that 1169 convention. 1170 1171- ``USE_DSU_DRIVER``: This flag enables DSU (DynamIQ Shared Unit) driver. 1172 The DSU driver allows save/restore of DSU PMU registers through 1173 ``PRESERVE_DSU_PMU_REGS`` build option, provides access to PMU registers at 1174 EL1 and allows platforms to configure powerdown and power settings of DSU. 1175 1176- ``ARM_IO_IN_DTB``: This flag determines whether to use IO based on the 1177 firmware configuration framework. This will move the io_policies into a 1178 configuration device tree, instead of static structure in the code base. 1179 1180- ``COT_DESC_IN_DTB``: This flag determines whether to create COT descriptors 1181 at runtime using fconf. If this flag is enabled, COT descriptors are 1182 statically captured in tb_fw_config file in the form of device tree nodes 1183 and properties. Currently, COT descriptors used by BL2 are moved to the 1184 device tree and COT descriptors used by BL1 are retained in the code 1185 base statically. 1186 1187- ``SDEI_IN_FCONF``: This flag determines whether to configure SDEI setup in 1188 runtime using firmware configuration framework. The platform specific SDEI 1189 shared and private events configuration is retrieved from device tree rather 1190 than static C structures at compile time. This is only supported if 1191 SDEI_SUPPORT build flag is enabled. 1192 1193- ``SEC_INT_DESC_IN_FCONF``: This flag determines whether to configure Group 0 1194 and Group1 secure interrupts using the firmware configuration framework. The 1195 platform specific secure interrupt property descriptor is retrieved from 1196 device tree in runtime rather than depending on static C structure at compile 1197 time. 1198 1199- ``USE_ROMLIB``: This flag determines whether library at ROM will be used. 1200 This feature creates a library of functions to be placed in ROM and thus 1201 reduces SRAM usage. Refer to :ref:`Library at ROM` for further details. Default 1202 is 0. 1203 1204- ``V``: Verbose build. If assigned anything other than 0, the build commands 1205 are printed. Default is 0. 1206 1207- ``VERSION_STRING``: String used in the log output for each TF-A image. 1208 Defaults to a string formed by concatenating the version number, build type 1209 and build string. 1210 1211- ``W``: Warning level. Some compiler warning options of interest have been 1212 regrouped and put in the root Makefile. This flag can take the values 0 to 3, 1213 each level enabling more warning options. Default is 0. 1214 1215 This option is closely related to the ``E`` option, which enables 1216 ``-Werror``. 1217 1218 - ``W=0`` (default) 1219 1220 Enables a wide assortment of warnings, most notably ``-Wall`` and 1221 ``-Wextra``, as well as various bad practices and things that are likely to 1222 result in errors. Includes some compiler specific flags. No warnings are 1223 expected at this level for any build. 1224 1225 - ``W=1`` 1226 1227 Enables warnings we want the generic build to include but are too time 1228 consuming to fix at the moment. It re-enables warnings taken out for 1229 ``W=0`` builds (a few of the ``-Wextra`` additions). This level is expected 1230 to eventually be merged into ``W=0``. Some warnings are expected on some 1231 builds, but new contributions should not introduce new ones. 1232 1233 - ``W=2`` (recommended) 1234 1235 Enables warnings we want the generic build to include but cannot be enabled 1236 due to external libraries. This level is expected to eventually be merged 1237 into ``W=0``. Lots of warnings are expected, primarily from external 1238 libraries like zlib and compiler-rt, but new controbutions should not 1239 introduce new ones. 1240 1241 - ``W=3`` 1242 1243 Enables warnings that are informative but not necessary and generally too 1244 verbose and frequently ignored. A very large number of warnings are 1245 expected. 1246 1247 The exact set of warning flags depends on the compiler and TF-A warning 1248 level, however they are all succinctly set in the top-level Makefile. Please 1249 refer to the `GCC`_ or `Clang`_ documentation for more information on the 1250 individual flags. 1251 1252- ``WARMBOOT_ENABLE_DCACHE_EARLY`` : Boolean option to enable D-cache early on 1253 the CPU after warm boot. This is applicable for platforms which do not 1254 require interconnect programming to enable cache coherency (eg: single 1255 cluster platforms). If this option is enabled, then warm boot path 1256 enables D-caches immediately after enabling MMU. This option defaults to 0. 1257 1258- ``ERRATA_SPECULATIVE_AT``: This flag determines whether to enable ``AT`` 1259 speculative errata workaround or not. It accepts 2 values: ``1`` and ``0``. 1260 The default value of this flag is ``0``. 1261 1262 ``AT`` speculative errata workaround disables stage1 page table walk for 1263 lower ELs (EL1 and EL0) in EL3 so that ``AT`` speculative fetch at any point 1264 produces either the correct result or failure without TLB allocation. 1265 1266 This boolean option enables errata for all below CPUs. 1267 1268 +---------+--------------+-------------------------+ 1269 | Errata | CPU | Workaround Define | 1270 +=========+==============+=========================+ 1271 | 1165522 | Cortex-A76 | ``ERRATA_A76_1165522`` | 1272 +---------+--------------+-------------------------+ 1273 | 1319367 | Cortex-A72 | ``ERRATA_A72_1319367`` | 1274 +---------+--------------+-------------------------+ 1275 | 1319537 | Cortex-A57 | ``ERRATA_A57_1319537`` | 1276 +---------+--------------+-------------------------+ 1277 | 1530923 | Cortex-A55 | ``ERRATA_A55_1530923`` | 1278 +---------+--------------+-------------------------+ 1279 | 1530924 | Cortex-A53 | ``ERRATA_A53_1530924`` | 1280 +---------+--------------+-------------------------+ 1281 1282 .. note:: 1283 This option is enabled by build only if platform sets any of above defines 1284 mentioned in ’Workaround Define' column in the table. 1285 If this option is enabled for the EL3 software then EL2 software also must 1286 implement this workaround due to the behaviour of the errata mentioned 1287 in new SDEN document which will get published soon. 1288 1289- ``ERRATA_SME_POWER_DOWN``: Boolean option to disable SME (PSTATE.{ZA,SM}=0) 1290 before power down and downgrade a suspend to power down request to a normal 1291 suspend request. This is necessary when software running at lower ELs requests 1292 power down without first clearing these bits. On affected cores, the CME 1293 connected to it will reject its power down request. The default value is 0. 1294 1295- ``RAS_TRAP_NS_ERR_REC_ACCESS``: This flag enables/disables the SCR_EL3.TERR 1296 bit, to trap access to the RAS ERR and RAS ERX registers from lower ELs. 1297 This flag is disabled by default. 1298 1299- ``OPENSSL_DIR``: This option is used to provide the path to a directory on the 1300 host machine where a custom installation of OpenSSL is located, which is used 1301 to build the certificate generation, firmware encryption and FIP tools. If 1302 this option is not set, the default OS installation will be used. 1303 1304- ``USE_SP804_TIMER``: Use the SP804 timer instead of the Generic Timer for 1305 functions that wait for an arbitrary time length (udelay and mdelay). The 1306 default value is 0. 1307 1308- ``ENABLE_BRBE_FOR_NS``: Numeric value to enable access to the branch record 1309 buffer registers from NS ELs when FEAT_BRBE is implemented. BRBE is an 1310 optional architectural feature for AArch64. This flag can take the values 1311 0 to 2, to align with the ``ENABLE_FEAT`` mechanism. The default is 0 1312 and it is automatically disabled when the target architecture is AArch32. 1313 1314- ``ENABLE_TRBE_FOR_NS``: Numeric value to enable access of trace buffer 1315 control registers from NS ELs, NS-EL2 or NS-EL1(when NS-EL2 is implemented 1316 but unused) when FEAT_TRBE is implemented. TRBE is an optional architectural 1317 feature for AArch64. This flag can take the values 0 to 2, to align with the 1318 ``ENABLE_FEAT`` mechanism. The default is 0 and it is automatically 1319 disabled when the target architecture is AArch32. 1320 1321- ``ENABLE_SYS_REG_TRACE_FOR_NS``: Numeric value to enable trace system 1322 registers access from NS ELs, NS-EL2 or NS-EL1 (when NS-EL2 is implemented 1323 but unused). This feature is available if trace unit such as ETMv4.x, and 1324 ETE(extending ETM feature) is implemented. This flag can take the values 1325 0 to 2, to align with the ``ENABLE_FEAT`` mechanism. The default is 0. 1326 1327- ``ENABLE_TRF_FOR_NS``: Numeric value to enable trace filter control registers 1328 access from NS ELs, NS-EL2 or NS-EL1 (when NS-EL2 is implemented but unused), 1329 if FEAT_TRF is implemented. This flag can take the values 0 to 2, to align 1330 with the ``ENABLE_FEAT`` mechanism. This flag is disabled by default. 1331 1332- ``CONDITIONAL_CMO``: Boolean option to enable call to platform-defined routine 1333 ``plat_can_cmo`` which will return zero if cache management operations should 1334 be skipped and non-zero otherwise. By default, this option is disabled which 1335 means platform hook won't be checked and CMOs will always be performed when 1336 related functions are called. 1337 1338- ``ERRATA_ABI_SUPPORT``: Boolean option to enable support for Errata management 1339 firmware interface for the BL31 image. By default its disabled (``0``). 1340 1341- ``ERRATA_NON_ARM_INTERCONNECT``: Boolean option to enable support for the 1342 errata mitigation for platforms with a non-arm interconnect using the errata 1343 ABI. By default its disabled (``0``). 1344 1345- ``ENABLE_CONSOLE_GETC``: Boolean option to enable `getc()` feature in console 1346 driver(s). By default it is disabled (``0``) because it constitutes an attack 1347 vector into TF-A by potentially allowing an attacker to inject arbitrary data. 1348 This option should only be enabled on a need basis if there is a use case for 1349 reading characters from the console. 1350 1351GIC driver options 1352-------------------- 1353 1354The generic GIC driver can be included with the ``USE_GIC_DRIVER`` option. It is 1355a numeric option that can take the following values: 1356 1357 - ``0``: generic GIC driver not enabled. Any support is entirely in platform 1358 code. Strongly discouraged for GIC based interrupt controllers. 1359 1360 - ``1``: enable the use of the generic GIC driver but do not include any files 1361 or function definitions. It is then the platform's responsibility to provide 1362 these. This is useful if the platform either has a custom GIC implementation 1363 or an alternative interrupt controller design. Use of this option is strongly 1364 discouraged for standard GIC implementations. 1365 1366 - ``2``: use the GICv2 driver 1367 1368 - ``3``: use the GICv3 driver. See the next section on how to further configure 1369 it. Use this option for GICv4 implementations. Requires calling 1370 ``gic_set_gicr_frames()``. 1371 1372 - ``5``: use the EXPERIMENTAL GICv5 driver. Requires ``ENABLE_FEAT_GCIE=1``. 1373 1374 For GIC driver versions other than ``1``, deciding when to save and restore GIC 1375 context on a power domain state transition, as well as any GIC actions outside 1376 of the PSCI library's visibility are the platform's responsibility. The driver 1377 provides implementations of all necessary subroutines, they only need to be 1378 called as appropriate. 1379 1380GICv3 driver options 1381~~~~~~~~~~~~~~~~~~~~ 1382 1383``USE_GIC_DRIVER=3`` is the preferred way of including GICv3 driver files. The 1384old (deprecated) way of included them is using the directive: 1385``include drivers/arm/gic/v3/gicv3.mk`` 1386 1387The driver can be configured with the following options set in the platform 1388makefile: 1389 1390- ``GICV3_SUPPORT_GIC600``: Add support for the GIC-600 variants of GICv3. 1391 Enabling this option will add runtime detection support for the 1392 GIC-600, so is safe to select even for a GIC500 implementation. 1393 This option defaults to 0. 1394 1395- ``GICV3_SUPPORT_GIC600AE_FMU``: Add support for the Fault Management Unit 1396 for GIC-600 AE. Enabling this option will introduce support to initialize 1397 the FMU. Platforms should call the init function during boot to enable the 1398 FMU and its safety mechanisms. This option defaults to 0. 1399 1400- ``GICV3_IMPL_GIC600_MULTICHIP``: Selects GIC-600 variant with multichip 1401 functionality. This option defaults to 0 1402 1403- ``GICV3_OVERRIDE_DISTIF_PWR_OPS``: Allows override of default implementation 1404 of ``arm_gicv3_distif_pre_save`` and ``arm_gicv3_distif_post_restore`` 1405 functions. This is required for FVP platform which need to simulate GIC save 1406 and restore during SYSTEM_SUSPEND without powering down GIC. Default is 0. 1407 1408- ``GIC_ENABLE_V4_EXTN`` : Enables GICv4 related changes in GICv3 driver. 1409 This option defaults to 0. 1410 1411- ``GIC_EXT_INTID``: When set to ``1``, GICv3 driver will support extended 1412 PPI (1056-1119) and SPI (4096-5119) range. This option defaults to 0. 1413 1414Debugging options 1415----------------- 1416 1417To compile a debug version and make the build more verbose use 1418 1419.. code:: shell 1420 1421 make PLAT=<platform> DEBUG=1 V=1 all 1422 1423AArch64 GCC 11 uses DWARF version 5 debugging symbols by default. Some tools 1424(for example Arm-DS) might not support this and may need an older version of 1425DWARF symbols to be emitted by GCC. This can be achieved by using the 1426``-gdwarf-<version>`` flag, with the version being set to 2, 3, 4 or 5. Setting 1427the version to 4 is recommended for Arm-DS. 1428 1429When debugging logic problems it might also be useful to disable all compiler 1430optimizations by using ``-O0``. 1431 1432.. warning:: 1433 Using ``-O0`` could cause output images to be larger and base addresses 1434 might need to be recalculated (see the **Memory layout on Arm development 1435 platforms** section in the :ref:`Firmware Design`). 1436 1437Extra debug options can be passed to the build system by setting ``CFLAGS`` or 1438``LDFLAGS``: 1439 1440.. code:: shell 1441 1442 CFLAGS='-O0 -gdwarf-2' \ 1443 make PLAT=<platform> DEBUG=1 V=1 all 1444 1445Note that using ``-Wl,`` style compilation driver options in ``CFLAGS`` will be 1446ignored as the linker is called directly. 1447 1448It is also possible to introduce an infinite loop to help in debugging the 1449post-BL2 phase of TF-A. This can be done by rebuilding BL1 with the 1450``SPIN_ON_BL1_EXIT=1`` build flag. Refer to the :ref:`build_options_common` 1451section. In this case, the developer may take control of the target using a 1452debugger when indicated by the console output. When using Arm-DS, the following 1453commands can be used: 1454 1455:: 1456 1457 # Stop target execution 1458 interrupt 1459 1460 # 1461 # Prepare your debugging environment, e.g. set breakpoints 1462 # 1463 1464 # Jump over the debug loop 1465 set var $AARCH64::$Core::$PC = $AARCH64::$Core::$PC + 4 1466 1467 # Resume execution 1468 continue 1469 1470.. _build_options_experimental: 1471 1472Experimental build options 1473--------------------------- 1474 1475Common build options 1476~~~~~~~~~~~~~~~~~~~~ 1477 1478- ``DICE_PROTECTION_ENVIRONMENT``: Boolean flag to specify the measured boot 1479 backend when ``MEASURED_BOOT`` is enabled. The default value is ``0``. When 1480 set to ``1`` then measurements and additional metadata collected during the 1481 measured boot process are sent to the DICE Protection Environment for storage 1482 and processing. A certificate chain, which represents the boot state of the 1483 device, can be queried from the DPE. 1484 1485- ``DRTM_SUPPORT``: Boolean flag to enable support for Dynamic Root of Trust 1486 for Measurement (DRTM). This feature has trust dependency on BL31 for taking 1487 the measurements and recording them as per `PSA DRTM specification`_. For 1488 platforms which use BL2 to load/authenticate BL31 ``TRUSTED_BOARD_BOOT`` can 1489 be used and for the platforms which use ``RESET_TO_BL31`` platform owners 1490 should have mechanism to authenticate BL31. This option defaults to 0. 1491 1492- ``ENABLE_RME``: Numeric value to enable support for the ARMv9 Realm 1493 Management Extension. This flag can take the values 0 to 2, to align with 1494 the ``ENABLE_FEAT`` mechanism. Default value is 0. 1495 1496- ``ENABLE_FEAT_MEC``: Numeric value to enable support for the ARMv9.2 Memory 1497 Encryption Contexts (MEC). This flag can take the values 0 to 2, to align 1498 with the ``ENABLE_FEAT`` mechanism. MEC supports multiple encryption 1499 contexts for Realm security state and only one encryption context for the 1500 rest of the security states. Default value is 0. 1501 1502- ``RMMD_ENABLE_EL3_TOKEN_SIGN``: Numeric value to enable support for singing 1503 realm attestation token signing requests in EL3. This flag can take the 1504 values 0 and 1. The default value is ``0``. When set to ``1``, this option 1505 enables additional RMMD SMCs to push and pop requests for signing to 1506 EL3 along with platform hooks that must be implemented to service those 1507 requests and responses. 1508 1509- ``ENABLE_SME_FOR_NS``: Numeric value to enable Scalable Matrix Extension 1510 (SME), SVE, and FPU/SIMD for the non-secure world only. These features share 1511 registers so are enabled together. Using this option without 1512 ENABLE_SME_FOR_SWD=1 will cause SME, SVE, and FPU/SIMD instructions in secure 1513 world to trap to EL3. Requires ``ENABLE_SVE_FOR_NS`` to be set as SME is a 1514 superset of SVE. SME is an optional architectural feature for AArch64. 1515 At this time, this build option cannot be used on systems that have 1516 SPD=spmd/SPM_MM and atempting to build with this option will fail. 1517 This flag can take the values 0 to 2, to align with the ``ENABLE_FEAT`` 1518 mechanism. Default is 0. 1519 1520- ``ENABLE_SME2_FOR_NS``: Numeric value to enable Scalable Matrix Extension 1521 version 2 (SME2) for the non-secure world only. SME2 is an optional 1522 architectural feature for AArch64. 1523 This should be set along with ENABLE_SME_FOR_NS=1, if not, the default SME 1524 accesses will still be trapped. This flag can take the values 0 to 2, to 1525 align with the ``ENABLE_FEAT`` mechanism. Default is 0. 1526 1527- ``ENABLE_SME_FOR_SWD``: Boolean option to enable the Scalable Matrix 1528 Extension for secure world. Used along with SVE and FPU/SIMD. 1529 ENABLE_SME_FOR_NS and ENABLE_SVE_FOR_SWD must also be set to use this. 1530 Default is 0. 1531 1532- ``ENABLE_SPMD_LP`` : This boolean option is used jointly with the SPM 1533 Dispatcher option (``SPD=spmd``). When enabled (1) it indicates support 1534 for logical partitions in EL3, managed by the SPMD as defined in the 1535 FF-A v1.2 specification. This flag is disabled by default. This flag 1536 must not be used if ``SPMC_AT_EL3`` is enabled. 1537 1538- ``FEATURE_DETECTION``: Boolean option to enable the architectural features 1539 verification mechanism. This is a debug feature that compares the 1540 architectural features enabled through the feature specific build flags 1541 (ENABLE_FEAT_xxx) with the features actually available on the CPU running, 1542 and reports any discrepancies. 1543 This flag will also enable errata ordering checking for ``DEBUG`` builds. 1544 1545 It is expected that this feature is only used for flexible platforms like 1546 software emulators, or for hardware platforms at bringup time, to verify 1547 that the configured feature set matches the CPU. 1548 The ``FEATURE_DETECTION`` macro is disabled by default. 1549 1550- ``PSA_CRYPTO``: Boolean option for enabling MbedTLS PSA crypto APIs support. 1551 The platform will use PSA compliant Crypto APIs during authentication and 1552 image measurement process by enabling this option. It uses APIs defined as 1553 per the `PSA Crypto API specification`_. This feature is only supported if 1554 using MbedTLS 3.x version. It is disabled (``0``) by default. 1555 1556- ``LFA_SUPPORT``: Boolean flag to enable support for Live Firmware 1557 activation as per the specification. This option defaults to 0. 1558 1559- ``TRANSFER_LIST``: Setting this to ``1`` enables support for Firmware 1560 Handoff using Transfer List defined in `Firmware Handoff specification`_. 1561 This defaults to ``0``. Current implementation follows the Firmware Handoff 1562 specification v0.9. 1563 1564- ``USE_DEBUGFS``: When set to 1 this option exposes a virtual filesystem 1565 interface through BL31 as a SiP SMC function. 1566 Default is disabled (0). 1567 1568- ``HOB_LIST``: Setting this to ``1`` enables support for passing boot 1569 information using HOB defined in `Platform Initialization specification`_. 1570 This defaults to ``0``. 1571 1572- ``ENABLE_ACS_SMC``: When set to ``1``, this enables support for ACS SMC 1573 handler code to handle SMC calls from the Architecture Compliance Suite. The 1574 handler is intentionally empty to reserve the SMC section and allow 1575 project-specific implementations in future ACS use cases. 1576 1577Firmware update options 1578~~~~~~~~~~~~~~~~~~~~~~~ 1579 1580- ``PSA_FWU_SUPPORT``: Enable the firmware update mechanism as per the 1581 `PSA FW update specification`_. The default value is 0. 1582 PSA firmware update implementation has few limitations, such as: 1583 1584 - BL2 is not part of the protocol-updatable images. If BL2 needs to 1585 be updated, then it should be done through another platform-defined 1586 mechanism. 1587 1588 - It assumes the platform's hardware supports CRC32 instructions. 1589 1590- ``NR_OF_FW_BANKS``: Define the number of firmware banks. This flag is used 1591 in defining the firmware update metadata structure. This flag is by default 1592 set to '2'. 1593 1594- ``NR_OF_IMAGES_IN_FW_BANK``: Define the number of firmware images in each 1595 firmware bank. Each firmware bank must have the same number of images as per 1596 the `PSA FW update specification`_. 1597 This flag is used in defining the firmware update metadata structure. This 1598 flag is by default set to '1'. 1599 1600- ``PSA_FWU_METADATA_FW_STORE_DESC``: To be enabled when the FWU 1601 metadata contains image description. The default value is 1. 1602 1603 The version 2 of the FWU metadata allows for an opaque metadata 1604 structure where a platform can choose to not include the firmware 1605 store description in the metadata structure. This option indicates 1606 if the firmware store description, which provides information on 1607 the updatable images is part of the structure. 1608 1609-------------- 1610 1611*Copyright (c) 2019-2025, Arm Limited. All rights reserved.* 1612 1613.. _DEN0115: https://developer.arm.com/docs/den0115/latest 1614.. _PSA FW update specification: https://developer.arm.com/documentation/den0118/latest/ 1615.. _PSA DRTM specification: https://developer.arm.com/documentation/den0113/a 1616.. _GCC: https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html 1617.. _Clang: https://clang.llvm.org/docs/DiagnosticsReference.html 1618.. _Firmware Handoff specification: https://github.com/FirmwareHandoff/firmware_handoff/releases/tag/v0.9 1619.. _PSA Crypto API specification: https://armmbed.github.io/mbed-crypto/html/ 1620.. _Platform Initialization specification: https://uefi.org/specs/PI/1.8/index.html 1621.. _TF-A public mailing list: https://lists.trustedfirmware.org/mailman3/lists/tf-a.lists.trustedfirmware.org/ 1622