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