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. Reads from the 27 memory mapped view are unaffected by this control. 28 29- ``ARCH`` : Choose the target build architecture for TF-A. It can take either 30 ``aarch64`` or ``aarch32`` as values. By default, it is defined to 31 ``aarch64``. 32 33- ``ARM_ARCH_FEATURE``: Optional Arm Architecture build option which specifies 34 one or more feature modifiers. This option has the form ``[no]feature+...`` 35 and defaults to ``none``. It translates into compiler option 36 ``-march=armvX[.Y]-a+[no]feature+...``. See compiler's documentation for the 37 list of supported feature modifiers. 38 39- ``ARM_ARCH_MAJOR``: The major version of Arm Architecture to target when 40 compiling TF-A. Its value must be numeric, and defaults to 8 . See also, 41 *Armv8 Architecture Extensions* and *Armv7 Architecture Extensions* in 42 :ref:`Firmware Design`. 43 44- ``ARM_ARCH_MINOR``: The minor version of Arm Architecture to target when 45 compiling TF-A. Its value must be a numeric, and defaults to 0. See also, 46 *Armv8 Architecture Extensions* in :ref:`Firmware Design`. 47 48- ``BL2``: This is an optional build option which specifies the path to BL2 49 image for the ``fip`` target. In this case, the BL2 in the TF-A will not be 50 built. 51 52- ``BL2U``: This is an optional build option which specifies the path to 53 BL2U image. In this case, the BL2U in TF-A will not be built. 54 55- ``BL2_AT_EL3``: This is an optional build option that enables the use of 56 BL2 at EL3 execution level. 57 58- ``BL2_ENABLE_SP_LOAD``: Boolean option to enable loading SP packages from the 59 FIP. Automatically enabled if ``SP_LAYOUT_FILE`` is provided. 60 61- ``BL2_IN_XIP_MEM``: In some use-cases BL2 will be stored in eXecute In Place 62 (XIP) memory, like BL1. In these use-cases, it is necessary to initialize 63 the RW sections in RAM, while leaving the RO sections in place. This option 64 enable this use-case. For now, this option is only supported when BL2_AT_EL3 65 is set to '1'. 66 67- ``BL31``: This is an optional build option which specifies the path to 68 BL31 image for the ``fip`` target. In this case, the BL31 in TF-A will not 69 be built. 70 71- ``BL31_KEY``: This option is used when ``GENERATE_COT=1``. It specifies the 72 file that contains the BL31 private key in PEM format. If ``SAVE_KEYS=1``, 73 this file name will be used to save the key. 74 75- ``BL32``: This is an optional build option which specifies the path to 76 BL32 image for the ``fip`` target. In this case, the BL32 in TF-A will not 77 be built. 78 79- ``BL32_EXTRA1``: This is an optional build option which specifies the path to 80 Trusted OS Extra1 image for the ``fip`` target. 81 82- ``BL32_EXTRA2``: This is an optional build option which specifies the path to 83 Trusted OS Extra2 image for the ``fip`` target. 84 85- ``BL32_KEY``: This option is used when ``GENERATE_COT=1``. It specifies the 86 file that contains the BL32 private key in PEM format. If ``SAVE_KEYS=1``, 87 this file name will be used to save the key. 88 89- ``BL33``: Path to BL33 image in the host file system. This is mandatory for 90 ``fip`` target in case TF-A BL2 is used. 91 92- ``BL33_KEY``: This option is used when ``GENERATE_COT=1``. It specifies the 93 file that contains the BL33 private key in PEM format. If ``SAVE_KEYS=1``, 94 this file name will be used to save the key. 95 96- ``BRANCH_PROTECTION``: Numeric value to enable ARMv8.3 Pointer Authentication 97 and ARMv8.5 Branch Target Identification support for TF-A BL images themselves. 98 If enabled, it is needed to use a compiler that supports the option 99 ``-mbranch-protection``. Selects the branch protection features to use: 100- 0: Default value turns off all types of branch protection 101- 1: Enables all types of branch protection features 102- 2: Return address signing to its standard level 103- 3: Extend the signing to include leaf functions 104- 4: Turn on branch target identification mechanism 105 106 The table below summarizes ``BRANCH_PROTECTION`` values, GCC compilation options 107 and resulting PAuth/BTI features. 108 109 +-------+--------------+-------+-----+ 110 | Value | GCC option | PAuth | BTI | 111 +=======+==============+=======+=====+ 112 | 0 | none | N | N | 113 +-------+--------------+-------+-----+ 114 | 1 | standard | Y | Y | 115 +-------+--------------+-------+-----+ 116 | 2 | pac-ret | Y | N | 117 +-------+--------------+-------+-----+ 118 | 3 | pac-ret+leaf | Y | N | 119 +-------+--------------+-------+-----+ 120 | 4 | bti | N | Y | 121 +-------+--------------+-------+-----+ 122 123 This option defaults to 0. 124 Note that Pointer Authentication is enabled for Non-secure world 125 irrespective of the value of this option if the CPU supports it. 126 127- ``BUILD_MESSAGE_TIMESTAMP``: String used to identify the time and date of the 128 compilation of each build. It must be set to a C string (including quotes 129 where applicable). Defaults to a string that contains the time and date of 130 the compilation. 131 132- ``BUILD_STRING``: Input string for VERSION_STRING, which allows the TF-A 133 build to be uniquely identified. Defaults to the current git commit id. 134 135- ``BUILD_BASE``: Output directory for the build. Defaults to ``./build`` 136 137- ``CFLAGS``: Extra user options appended on the compiler's command line in 138 addition to the options set by the build system. 139 140- ``COLD_BOOT_SINGLE_CPU``: This option indicates whether the platform may 141 release several CPUs out of reset. It can take either 0 (several CPUs may be 142 brought up) or 1 (only one CPU will ever be brought up during cold reset). 143 Default is 0. If the platform always brings up a single CPU, there is no 144 need to distinguish between primary and secondary CPUs and the boot path can 145 be optimised. The ``plat_is_my_cpu_primary()`` and 146 ``plat_secondary_cold_boot_setup()`` platform porting interfaces do not need 147 to be implemented in this case. 148 149- ``COT``: When Trusted Boot is enabled, selects the desired chain of trust. 150 Defaults to ``tbbr``. 151 152- ``CRASH_REPORTING``: A non-zero value enables a console dump of processor 153 register state when an unexpected exception occurs during execution of 154 BL31. This option defaults to the value of ``DEBUG`` - i.e. by default 155 this is only enabled for a debug build of the firmware. 156 157- ``CREATE_KEYS``: This option is used when ``GENERATE_COT=1``. It tells the 158 certificate generation tool to create new keys in case no valid keys are 159 present or specified. Allowed options are '0' or '1'. Default is '1'. 160 161- ``CTX_INCLUDE_AARCH32_REGS`` : Boolean option that, when set to 1, will cause 162 the AArch32 system registers to be included when saving and restoring the 163 CPU context. The option must be set to 0 for AArch64-only platforms (that 164 is on hardware that does not implement AArch32, or at least not at EL1 and 165 higher ELs). Default value is 1. 166 167- ``CTX_INCLUDE_EL2_REGS`` : This boolean option provides context save/restore 168 operations when entering/exiting an EL2 execution context. This is of primary 169 interest when Armv8.4-SecEL2 extension is implemented. Default is 0 (disabled). 170 This option must be equal to 1 (enabled) when ``SPD=spmd`` and 171 ``SPMD_SPM_AT_SEL2`` is set. 172 173- ``CTX_INCLUDE_FPREGS``: Boolean option that, when set to 1, will cause the FP 174 registers to be included when saving and restoring the CPU context. Default 175 is 0. 176 177- ``CTX_INCLUDE_MTE_REGS``: Numeric value to include Memory Tagging Extension 178 registers in cpu context. This must be enabled, if the platform wants to use 179 this feature in the Secure world and MTE is enabled at ELX. This flag can 180 take values 0 to 2, to align with the ``FEATURE_DETECTION`` mechanism. 181 Default value is 0. 182 183- ``CTX_INCLUDE_NEVE_REGS``: Numeric value, when set will cause the Armv8.4-NV 184 registers to be saved/restored when entering/exiting an EL2 execution 185 context. This flag can take values 0 to 2, to align with the 186 ``FEATURE_DETECTION`` mechanism. Default value is 0. 187 188- ``CTX_INCLUDE_PAUTH_REGS``: Numeric value to enable the Pointer 189 Authentication for Secure world. This will cause the ARMv8.3-PAuth registers 190 to be included when saving and restoring the CPU context as part of world 191 switch. This flag can take values 0 to 2, to align with ``FEATURE_DETECTION`` 192 mechanism. Default value is 0. 193 194 Note that Pointer Authentication is enabled for Non-secure world irrespective 195 of the value of this flag if the CPU supports it. 196 197- ``DEBUG``: Chooses between a debug and release build. It can take either 0 198 (release) or 1 (debug) as values. 0 is the default. 199 200- ``DECRYPTION_SUPPORT``: This build flag enables the user to select the 201 authenticated decryption algorithm to be used to decrypt firmware/s during 202 boot. It accepts 2 values: ``aes_gcm`` and ``none``. The default value of 203 this flag is ``none`` to disable firmware decryption which is an optional 204 feature as per TBBR. 205 206- ``DISABLE_BIN_GENERATION``: Boolean option to disable the generation 207 of the binary image. If set to 1, then only the ELF image is built. 208 0 is the default. 209 210- ``DISABLE_MTPMU``: Boolean option to disable FEAT_MTPMU if implemented 211 (Armv8.6 onwards). Its default value is 0 to keep consistency with platforms 212 that do not implement FEAT_MTPMU. For more information on FEAT_MTPMU, 213 check the latest Arm ARM. 214 215- ``DYN_DISABLE_AUTH``: Provides the capability to dynamically disable Trusted 216 Board Boot authentication at runtime. This option is meant to be enabled only 217 for development platforms. ``TRUSTED_BOARD_BOOT`` flag must be set if this 218 flag has to be enabled. 0 is the default. 219 220- ``E``: Boolean option to make warnings into errors. Default is 1. 221 222- ``EL3_PAYLOAD_BASE``: This option enables booting an EL3 payload instead of 223 the normal boot flow. It must specify the entry point address of the EL3 224 payload. Please refer to the "Booting an EL3 payload" section for more 225 details. 226 227- ``ENABLE_AMU``: Boolean option to enable Activity Monitor Unit extensions. 228 This is an optional architectural feature available on v8.4 onwards. Some 229 v8.2 implementations also implement an AMU and this option can be used to 230 enable this feature on those systems as well. Default is 0. 231 232- ``ENABLE_AMU_AUXILIARY_COUNTERS``: Enables support for AMU auxiliary counters 233 (also known as group 1 counters). These are implementation-defined counters, 234 and as such require additional platform configuration. Default is 0. 235 236- ``ENABLE_AMU_FCONF``: Enables configuration of the AMU through FCONF, which 237 allows platforms with auxiliary counters to describe them via the 238 ``HW_CONFIG`` device tree blob. Default is 0. 239 240- ``ENABLE_ASSERTIONS``: This option controls whether or not calls to ``assert()`` 241 are compiled out. For debug builds, this option defaults to 1, and calls to 242 ``assert()`` are left in place. For release builds, this option defaults to 0 243 and calls to ``assert()`` function are compiled out. This option can be set 244 independently of ``DEBUG``. It can also be used to hide any auxiliary code 245 that is only required for the assertion and does not fit in the assertion 246 itself. 247 248- ``ENABLE_BACKTRACE``: This option controls whether to enable backtrace 249 dumps or not. It is supported in both AArch64 and AArch32. However, in 250 AArch32 the format of the frame records are not defined in the AAPCS and they 251 are defined by the implementation. This implementation of backtrace only 252 supports the format used by GCC when T32 interworking is disabled. For this 253 reason enabling this option in AArch32 will force the compiler to only 254 generate A32 code. This option is enabled by default only in AArch64 debug 255 builds, but this behaviour can be overridden in each platform's Makefile or 256 in the build command line. 257 258- ``ENABLE_FEAT_AMUv1``: Numeric value to enable access to the HAFGRTR_EL2 259 (Hypervisor Activity Monitors Fine-Grained Read Trap Register) during EL2 260 to EL3 context save/restore operations. This flag can take the values 0 to 2, 261 to align with the ``FEATURE_DETECTION`` mechanism. It is an optional feature 262 available on v8.4 and onwards and must be set to either 1 or 2 alongside 263 ``ENABLE_FEAT_FGT``, to access the HAFGRTR_EL2 register. 264 Default value is ``0``. 265 266- ``ENABLE_FEAT_AMUv1p1``: Numeric value to enable the ``FEAT_AMUv1p1`` 267 extension. ``FEAT_AMUv1p1`` is an optional feature available on Arm v8.6 268 onwards. This flag can take the values 0 to 2, to align with the 269 ``FEATURE_DETECTION`` mechanism. Default value is ``0``. 270 271- ``ENABLE_FEAT_CSV2_2``: Numeric value to enable the ``FEAT_CSV2_2`` 272 extension. It allows access to the SCXTNUM_EL2 (Software Context Number) 273 register during EL2 context save/restore operations. ``FEAT_CSV2_2`` is an 274 optional feature available on Arm v8.0 onwards. This flag can take values 275 0 to 2, to align with the ``FEATURE_DETECTION`` mechanism. 276 Default value is ``0``. 277 278- ``ENABLE_FEAT_DIT``: Numeric value to enable ``FEAT_DIT`` (Data Independent 279 Timing) extension. It allows setting the ``DIT`` bit of PSTATE in EL3. 280 ``FEAT_DIT`` is a mandatory architectural feature and is enabled from v8.4 281 and upwards. This flag can take the values 0 to 2, to align with the 282 ``FEATURE_DETECTION`` mechanism. Default value is ``0``. 283 284- ``ENABLE_FEAT_ECV``: Numeric value to enable support for the Enhanced Counter 285 Virtualization feature, allowing for access to the CNTPOFF_EL2 (Counter-timer 286 Physical Offset register) during EL2 to EL3 context save/restore operations. 287 Its a mandatory architectural feature and is enabled from v8.6 and upwards. 288 This flag can take the values 0 to 2, to align with the ``FEATURE_DETECTION`` 289 mechanism. Default value is ``0``. 290 291- ``ENABLE_FEAT_FGT``: Numeric value to enable support for FGT (Fine Grain Traps) 292 feature allowing for access to the HDFGRTR_EL2 (Hypervisor Debug Fine-Grained 293 Read Trap Register) during EL2 to EL3 context save/restore operations. 294 Its a mandatory architectural feature and is enabled from v8.6 and upwards. 295 This flag can take the values 0 to 2, to align with the ``FEATURE_DETECTION`` 296 mechanism. Default value is ``0``. 297 298- ``ENABLE_FEAT_HCX``: Numeric value to set the bit SCR_EL3.HXEn in EL3 to 299 allow access to HCRX_EL2 (extended hypervisor control register) from EL2 as 300 well as adding HCRX_EL2 to the EL2 context save/restore operations. Its a 301 mandatory architectural feature and is enabled from v8.7 and upwards. This 302 flag can take the values 0 to 2, to align with the ``FEATURE_DETECTION`` 303 mechanism. Default value is ``0``. 304 305- ``ENABLE_FEAT_PAN``: Numeric value to enable the ``FEAT_PAN`` (Privileged 306 Access Never) extension. ``FEAT_PAN`` adds a bit to PSTATE, generating a 307 permission fault for any privileged data access from EL1/EL2 to virtual 308 memory address, accessible at EL0, provided (HCR_EL2.E2H=1). It is a 309 mandatory architectural feature and is enabled from v8.1 and upwards. This 310 flag can take values 0 to 2, to align with the ``FEATURE_DETECTION`` 311 mechanism. Default value is ``0``. 312 313- ``ENABLE_FEAT_RNG``: Numeric value to enable the ``FEAT_RNG`` extension. 314 ``FEAT_RNG`` is an optional feature available on Arm v8.5 onwards. This 315 flag can take the values 0 to 2, to align with the ``FEATURE_DETECTION`` 316 mechanism. Default value is ``0``. 317 318- ``ENABLE_FEAT_RNG_TRAP``: Numeric value to enable the ``FEAT_RNG_TRAP`` 319 extension. This feature is only supported in AArch64 state. This flag can 320 take values 0 to 2, to align with the ``FEATURE_DETECTION`` mechanism. 321 Default value is ``0``. ``FEAT_RNG_TRAP`` is an optional feature from 322 Armv8.5 onwards. 323 324- ``ENABLE_FEAT_SB``: Numeric value to enable the ``FEAT_SB`` (Speculation 325 Barrier) extension allowing access to ``sb`` instruction. ``FEAT_SB`` is an 326 optional feature and defaults to ``0`` for pre-Armv8.5 CPUs but are mandatory 327 for Armv8.5 or later CPUs. This flag can take values 0 to 2, to align with 328 ``FEATURE_DETECTION`` mechanism. It is enabled from v8.5 and upwards and if 329 needed could be overidden from platforms explicitly. Default value is ``0``. 330 331- ``ENABLE_FEAT_SEL2``: Numeric value to enable the ``FEAT_SEL2`` (Secure EL2) 332 extension. ``FEAT_SEL2`` is a mandatory feature available on Arm v8.4. 333 This flag can take values 0 to 2, to align with the ``FEATURE_DETECTION`` 334 mechanism. Default is ``0``. 335 336- ``ENABLE_FEAT_TWED``: Numeric value to enable the ``FEAT_TWED`` (Delayed 337 trapping of WFE Instruction) extension. ``FEAT_TWED`` is a optional feature 338 available on Arm v8.6. This flag can take values 0 to 2, to align with the 339 ``FEATURE_DETECTION`` mechanism. Default is ``0``. 340 341 When ``ENABLE_FEAT_TWED`` is set to ``1``, WFE instruction trapping gets 342 delayed by the amount of value in ``TWED_DELAY``. 343 344- ``ENABLE_FEAT_VHE``: Numeric value to enable the ``FEAT_VHE`` (Virtualization 345 Host Extensions) extension. It allows access to CONTEXTIDR_EL2 register 346 during EL2 context save/restore operations.``FEAT_VHE`` is a mandatory 347 architectural feature and is enabled from v8.1 and upwards. It can take 348 values 0 to 2, to align with the ``FEATURE_DETECTION`` mechanism. 349 Default value is ``0``. 350 351- ``ENABLE_LTO``: Boolean option to enable Link Time Optimization (LTO) 352 support in GCC for TF-A. This option is currently only supported for 353 AArch64. Default is 0. 354 355- ``ENABLE_MPAM_FOR_LOWER_ELS``: Numeric value to enable lower ELs to use MPAM 356 feature. MPAM is an optional Armv8.4 extension that enables various memory 357 system components and resources to define partitions; software running at 358 various ELs can assign themselves to desired partition to control their 359 performance aspects. 360 361 This flag can take values 0 to 2, to align with the ``FEATURE_DETECTION`` 362 mechanism. When this option is set to ``1`` or ``2``, EL3 allows lower ELs to 363 access their own MPAM registers without trapping into EL3. This option 364 doesn't make use of partitioning in EL3, however. Platform initialisation 365 code should configure and use partitions in EL3 as required. This option 366 defaults to ``0``. 367 368- ``ENABLE_MPMM``: Boolean option to enable support for the Maximum Power 369 Mitigation Mechanism supported by certain Arm cores, which allows the SoC 370 firmware to detect and limit high activity events to assist in SoC processor 371 power domain dynamic power budgeting and limit the triggering of whole-rail 372 (i.e. clock chopping) responses to overcurrent conditions. Defaults to ``0``. 373 374- ``ENABLE_MPMM_FCONF``: Enables configuration of MPMM through FCONF, which 375 allows platforms with cores supporting MPMM to describe them via the 376 ``HW_CONFIG`` device tree blob. Default is 0. 377 378- ``ENABLE_PIE``: Boolean option to enable Position Independent Executable(PIE) 379 support within generic code in TF-A. This option is currently only supported 380 in BL2_AT_EL3, BL31, and BL32 (TSP) for AARCH64 binaries, and in BL32 381 (SP_min) for AARCH32. Default is 0. 382 383- ``ENABLE_PMF``: Boolean option to enable support for optional Performance 384 Measurement Framework(PMF). Default is 0. 385 386- ``ENABLE_PSCI_STAT``: Boolean option to enable support for optional PSCI 387 functions ``PSCI_STAT_RESIDENCY`` and ``PSCI_STAT_COUNT``. Default is 0. 388 In the absence of an alternate stat collection backend, ``ENABLE_PMF`` must 389 be enabled. If ``ENABLE_PMF`` is set, the residency statistics are tracked in 390 software. 391 392- ``ENABLE_RME``: Numeric value to enable support for the ARMv9 Realm 393 Management Extension. This flag can take the values 0 to 2, to align with 394 the ``FEATURE_DETECTION`` mechanism. Default value is 0. This is currently 395 an experimental feature. 396 397- ``ENABLE_RUNTIME_INSTRUMENTATION``: Boolean option to enable runtime 398 instrumentation which injects timestamp collection points into TF-A to 399 allow runtime performance to be measured. Currently, only PSCI is 400 instrumented. Enabling this option enables the ``ENABLE_PMF`` build option 401 as well. Default is 0. 402 403- ``ENABLE_SME_FOR_NS``: Boolean option to enable Scalable Matrix Extension 404 (SME), SVE, and FPU/SIMD for the non-secure world only. These features share 405 registers so are enabled together. Using this option without 406 ENABLE_SME_FOR_SWD=1 will cause SME, SVE, and FPU/SIMD instructions in secure 407 world to trap to EL3. SME is an optional architectural feature for AArch64 408 and TF-A support is experimental. At this time, this build option cannot be 409 used on systems that have SPD=spmd/SPM_MM or ENABLE_RME, and attempting to 410 build with these options will fail. Default is 0. 411 412- ``ENABLE_SME_FOR_SWD``: Boolean option to enable the Scalable Matrix 413 Extension for secure world use along with SVE and FPU/SIMD, ENABLE_SME_FOR_NS 414 must also be set to use this. If enabling this, the secure world MUST 415 handle context switching for SME, SVE, and FPU/SIMD registers to ensure that 416 no data is leaked to non-secure world. This is experimental. Default is 0. 417 418- ``ENABLE_SPE_FOR_LOWER_ELS`` : Boolean option to enable Statistical Profiling 419 extensions. This is an optional architectural feature for AArch64. 420 The default is 1 but is automatically disabled when the target architecture 421 is AArch32. 422 423- ``ENABLE_SVE_FOR_NS``: Boolean option to enable Scalable Vector Extension 424 (SVE) for the Non-secure world only. SVE is an optional architectural feature 425 for AArch64. Note that when SVE is enabled for the Non-secure world, access 426 to SIMD and floating-point functionality from the Secure world is disabled by 427 default and controlled with ENABLE_SVE_FOR_SWD. 428 This is to avoid corruption of the Non-secure world data in the Z-registers 429 which are aliased by the SIMD and FP registers. The build option is not 430 compatible with the ``CTX_INCLUDE_FPREGS`` build option, and will raise an 431 assert on platforms where SVE is implemented and ``ENABLE_SVE_FOR_NS`` set to 432 1. The default is 1 but is automatically disabled when ENABLE_SME_FOR_NS=1 433 since SME encompasses SVE. At this time, this build option cannot be used on 434 systems that have SPM_MM enabled. 435 436- ``ENABLE_SVE_FOR_SWD``: Boolean option to enable SVE for the Secure world. 437 SVE is an optional architectural feature for AArch64. Note that this option 438 requires ENABLE_SVE_FOR_NS to be enabled. The default is 0 and it 439 is automatically disabled when the target architecture is AArch32. 440 441- ``ENABLE_STACK_PROTECTOR``: String option to enable the stack protection 442 checks in GCC. Allowed values are "all", "strong", "default" and "none". The 443 default value is set to "none". "strong" is the recommended stack protection 444 level if this feature is desired. "none" disables the stack protection. For 445 all values other than "none", the ``plat_get_stack_protector_canary()`` 446 platform hook needs to be implemented. The value is passed as the last 447 component of the option ``-fstack-protector-$ENABLE_STACK_PROTECTOR``. 448 449- ``ENCRYPT_BL31``: Binary flag to enable encryption of BL31 firmware. This 450 flag depends on ``DECRYPTION_SUPPORT`` build flag. 451 452- ``ENCRYPT_BL32``: Binary flag to enable encryption of Secure BL32 payload. 453 This flag depends on ``DECRYPTION_SUPPORT`` build flag. 454 455- ``ENC_KEY``: A 32-byte (256-bit) symmetric key in hex string format. It could 456 either be SSK or BSSK depending on ``FW_ENC_STATUS`` flag. This value depends 457 on ``DECRYPTION_SUPPORT`` build flag. 458 459- ``ENC_NONCE``: A 12-byte (96-bit) encryption nonce or Initialization Vector 460 (IV) in hex string format. This value depends on ``DECRYPTION_SUPPORT`` 461 build flag. 462 463- ``ERROR_DEPRECATED``: This option decides whether to treat the usage of 464 deprecated platform APIs, helper functions or drivers within Trusted 465 Firmware as error. It can take the value 1 (flag the use of deprecated 466 APIs as error) or 0. The default is 0. 467 468- ``EL3_EXCEPTION_HANDLING``: When set to ``1``, enable handling of exceptions 469 targeted at EL3. When set ``0`` (default), no exceptions are expected or 470 handled at EL3, and a panic will result. The exception to this rule is when 471 ``SPMD_SPM_AT_SEL2`` is set to ``1``, in which case, only exceptions 472 occuring during normal world execution, are trapped to EL3. Any exception 473 trapped during secure world execution are trapped to the SPMC. This is 474 supported only for AArch64 builds. 475 476- ``EVENT_LOG_LEVEL``: Chooses the log level to use for Measured Boot when 477 ``MEASURED_BOOT`` is enabled. For a list of valid values, see ``LOG_LEVEL``. 478 Default value is 40 (LOG_LEVEL_INFO). 479 480- ``FAULT_INJECTION_SUPPORT``: ARMv8.4 extensions introduced support for fault 481 injection from lower ELs, and this build option enables lower ELs to use 482 Error Records accessed via System Registers to inject faults. This is 483 applicable only to AArch64 builds. 484 485 This feature is intended for testing purposes only, and is advisable to keep 486 disabled for production images. 487 488- ``FEATURE_DETECTION``: Boolean option to enable the architectural features 489 detection mechanism. It detects whether the Architectural features enabled 490 through feature specific build flags are supported by the PE or not by 491 validating them either at boot phase or at runtime based on the value 492 possessed by the feature flag (0 to 2) and report error messages at an early 493 stage. 494 495 This prevents and benefits us from EL3 runtime exceptions during context save 496 and restore routines guarded by these build flags. Henceforth validating them 497 before their usage provides more control on the actions taken under them. 498 499 The mechanism permits the build flags to take values 0, 1 or 2 and 500 evaluates them accordingly. 501 502 Lets consider ``ENABLE_FEAT_HCX``, build flag for ``FEAT_HCX`` as an example: 503 504 :: 505 506 ENABLE_FEAT_HCX = 0: Feature disabled statically at compile time. 507 ENABLE_FEAT_HCX = 1: Feature Enabled and the flag is validated at boottime. 508 ENABLE_FEAT_HCX = 2: Feature Enabled and the flag is validated at runtime. 509 510 In the above example, if the feature build flag, ``ENABLE_FEAT_HCX`` set to 511 0, feature is disabled statically during compilation. If it is defined as 1, 512 feature is validated, wherein FEAT_HCX is detected at boot time. In case not 513 implemented by the PE, a hard panic is generated. Finally, if the flag is set 514 to 2, feature is validated at runtime. 515 516 Note that the entire implementation is divided into two phases, wherein as 517 as part of phase-1 we are supporting the values 0,1. Value 2 is currently not 518 supported and is planned to be handled explicilty in phase-2 implementation. 519 520 FEATURE_DETECTION macro is disabled by default, and is currently an 521 experimental procedure. Platforms can explicitly make use of this by 522 mechanism, by enabling it to validate whether they have set their build flags 523 properly at an early phase. 524 525- ``FIP_NAME``: This is an optional build option which specifies the FIP 526 filename for the ``fip`` target. Default is ``fip.bin``. 527 528- ``FWU_FIP_NAME``: This is an optional build option which specifies the FWU 529 FIP filename for the ``fwu_fip`` target. Default is ``fwu_fip.bin``. 530 531- ``FW_ENC_STATUS``: Top level firmware's encryption numeric flag, values: 532 533 :: 534 535 0: Encryption is done with Secret Symmetric Key (SSK) which is common 536 for a class of devices. 537 1: Encryption is done with Binding Secret Symmetric Key (BSSK) which is 538 unique per device. 539 540 This flag depends on ``DECRYPTION_SUPPORT`` build flag. 541 542- ``GENERATE_COT``: Boolean flag used to build and execute the ``cert_create`` 543 tool to create certificates as per the Chain of Trust described in 544 :ref:`Trusted Board Boot`. The build system then calls ``fiptool`` to 545 include the certificates in the FIP and FWU_FIP. Default value is '0'. 546 547 Specify both ``TRUSTED_BOARD_BOOT=1`` and ``GENERATE_COT=1`` to include support 548 for the Trusted Board Boot feature in the BL1 and BL2 images, to generate 549 the corresponding certificates, and to include those certificates in the 550 FIP and FWU_FIP. 551 552 Note that if ``TRUSTED_BOARD_BOOT=0`` and ``GENERATE_COT=1``, the BL1 and BL2 553 images will not include support for Trusted Board Boot. The FIP will still 554 include the corresponding certificates. This FIP can be used to verify the 555 Chain of Trust on the host machine through other mechanisms. 556 557 Note that if ``TRUSTED_BOARD_BOOT=1`` and ``GENERATE_COT=0``, the BL1 and BL2 558 images will include support for Trusted Board Boot, but the FIP and FWU_FIP 559 will not include the corresponding certificates, causing a boot failure. 560 561- ``GICV2_G0_FOR_EL3``: Unlike GICv3, the GICv2 architecture doesn't have 562 inherent support for specific EL3 type interrupts. Setting this build option 563 to ``1`` assumes GICv2 *Group 0* interrupts are expected to target EL3, both 564 by :ref:`platform abstraction layer<platform Interrupt Controller API>` and 565 :ref:`Interrupt Management Framework<Interrupt Management Framework>`. 566 This allows GICv2 platforms to enable features requiring EL3 interrupt type. 567 This also means that all GICv2 Group 0 interrupts are delivered to EL3, and 568 the Secure Payload interrupts needs to be synchronously handed over to Secure 569 EL1 for handling. The default value of this option is ``0``, which means the 570 Group 0 interrupts are assumed to be handled by Secure EL1. 571 572- ``HANDLE_EA_EL3_FIRST_NS``: When set to ``1``, External Aborts and SError 573 Interrupts, resulting from errors in NS world, will be always trapped in 574 EL3 i.e. in BL31 at runtime. When set to ``0`` (default), these exceptions 575 will be trapped in the current exception level (or in EL1 if the current 576 exception level is EL0). 577 578- ``HW_ASSISTED_COHERENCY``: On most Arm systems to-date, platform-specific 579 software operations are required for CPUs to enter and exit coherency. 580 However, newer systems exist where CPUs' entry to and exit from coherency 581 is managed in hardware. Such systems require software to only initiate these 582 operations, and the rest is managed in hardware, minimizing active software 583 management. In such systems, this boolean option enables TF-A to carry out 584 build and run-time optimizations during boot and power management operations. 585 This option defaults to 0 and if it is enabled, then it implies 586 ``WARMBOOT_ENABLE_DCACHE_EARLY`` is also enabled. 587 588 If this flag is disabled while the platform which TF-A is compiled for 589 includes cores that manage coherency in hardware, then a compilation error is 590 generated. This is based on the fact that a system cannot have, at the same 591 time, cores that manage coherency in hardware and cores that don't. In other 592 words, a platform cannot have, at the same time, cores that require 593 ``HW_ASSISTED_COHERENCY=1`` and cores that require 594 ``HW_ASSISTED_COHERENCY=0``. 595 596 Note that, when ``HW_ASSISTED_COHERENCY`` is enabled, version 2 of 597 translation library (xlat tables v2) must be used; version 1 of translation 598 library is not supported. 599 600- ``INVERTED_MEMMAP``: memmap tool print by default lower addresses at the 601 bottom, higher addresses at the top. This build flag can be set to '1' to 602 invert this behavior. Lower addresses will be printed at the top and higher 603 addresses at the bottom. 604 605- ``JUNO_AARCH32_EL3_RUNTIME``: This build flag enables you to execute EL3 606 runtime software in AArch32 mode, which is required to run AArch32 on Juno. 607 By default this flag is set to '0'. Enabling this flag builds BL1 and BL2 in 608 AArch64 and facilitates the loading of ``SP_MIN`` and BL33 as AArch32 executable 609 images. 610 611- ``KEY_ALG``: This build flag enables the user to select the algorithm to be 612 used for generating the PKCS keys and subsequent signing of the certificate. 613 It accepts 3 values: ``rsa``, ``rsa_1_5`` and ``ecdsa``. The option 614 ``rsa_1_5`` is the legacy PKCS#1 RSA 1.5 algorithm which is not TBBR 615 compliant and is retained only for compatibility. The default value of this 616 flag is ``rsa`` which is the TBBR compliant PKCS#1 RSA 2.1 scheme. 617 618- ``KEY_SIZE``: This build flag enables the user to select the key size for 619 the algorithm specified by ``KEY_ALG``. The valid values for ``KEY_SIZE`` 620 depend on the chosen algorithm and the cryptographic module. 621 622 +-----------+------------------------------------+ 623 | KEY_ALG | Possible key sizes | 624 +===========+====================================+ 625 | rsa | 1024 , 2048 (default), 3072, 4096* | 626 +-----------+------------------------------------+ 627 | ecdsa | unavailable | 628 +-----------+------------------------------------+ 629 630 * Only 2048 bits size is available with CryptoCell 712 SBROM release 1. 631 Only 3072 bits size is available with CryptoCell 712 SBROM release 2. 632 633- ``HASH_ALG``: This build flag enables the user to select the secure hash 634 algorithm. It accepts 3 values: ``sha256``, ``sha384`` and ``sha512``. 635 The default value of this flag is ``sha256``. 636 637- ``LDFLAGS``: Extra user options appended to the linkers' command line in 638 addition to the one set by the build system. 639 640- ``LOG_LEVEL``: Chooses the log level, which controls the amount of console log 641 output compiled into the build. This should be one of the following: 642 643 :: 644 645 0 (LOG_LEVEL_NONE) 646 10 (LOG_LEVEL_ERROR) 647 20 (LOG_LEVEL_NOTICE) 648 30 (LOG_LEVEL_WARNING) 649 40 (LOG_LEVEL_INFO) 650 50 (LOG_LEVEL_VERBOSE) 651 652 All log output up to and including the selected log level is compiled into 653 the build. The default value is 40 in debug builds and 20 in release builds. 654 655- ``MEASURED_BOOT``: Boolean flag to include support for the Measured Boot 656 feature. This flag can be enabled with ``TRUSTED_BOARD_BOOT`` in order to 657 provide trust that the code taking the measurements and recording them has 658 not been tampered with. 659 660 This option defaults to 0. 661 662- ``DRTM_SUPPORT``: Boolean flag to enable support for Dynamic Root of Trust 663 for Measurement (DRTM). This feature has trust dependency on BL31 for taking 664 the measurements and recording them as per `PSA DRTM specification`_. For 665 platforms which use BL2 to load/authenticate BL31 ``TRUSTED_BOARD_BOOT`` can 666 be used and for the platforms which use ``RESET_TO_BL31`` platform owners 667 should have mechanism to authenticate BL31. 668 669 This option defaults to 0. 670 671- ``NON_TRUSTED_WORLD_KEY``: This option is used when ``GENERATE_COT=1``. It 672 specifies the file that contains the Non-Trusted World private key in PEM 673 format. If ``SAVE_KEYS=1``, this file name will be used to save the key. 674 675- ``NS_BL2U``: Path to NS_BL2U image in the host file system. This image is 676 optional. It is only needed if the platform makefile specifies that it 677 is required in order to build the ``fwu_fip`` target. 678 679- ``NS_TIMER_SWITCH``: Enable save and restore for non-secure timer register 680 contents upon world switch. It can take either 0 (don't save and restore) or 681 1 (do save and restore). 0 is the default. An SPD may set this to 1 if it 682 wants the timer registers to be saved and restored. 683 684- ``OVERRIDE_LIBC``: This option allows platforms to override the default libc 685 for the BL image. It can be either 0 (include) or 1 (remove). The default 686 value is 0. 687 688- ``PL011_GENERIC_UART``: Boolean option to indicate the PL011 driver that 689 the underlying hardware is not a full PL011 UART but a minimally compliant 690 generic UART, which is a subset of the PL011. The driver will not access 691 any register that is not part of the SBSA generic UART specification. 692 Default value is 0 (a full PL011 compliant UART is present). 693 694- ``PLAT``: Choose a platform to build TF-A for. The chosen platform name 695 must be subdirectory of any depth under ``plat/``, and must contain a 696 platform makefile named ``platform.mk``. For example, to build TF-A for the 697 Arm Juno board, select PLAT=juno. 698 699- ``PRELOADED_BL33_BASE``: This option enables booting a preloaded BL33 image 700 instead of the normal boot flow. When defined, it must specify the entry 701 point address for the preloaded BL33 image. This option is incompatible with 702 ``EL3_PAYLOAD_BASE``. If both are defined, ``EL3_PAYLOAD_BASE`` has priority 703 over ``PRELOADED_BL33_BASE``. 704 705- ``PROGRAMMABLE_RESET_ADDRESS``: This option indicates whether the reset 706 vector address can be programmed or is fixed on the platform. It can take 707 either 0 (fixed) or 1 (programmable). Default is 0. If the platform has a 708 programmable reset address, it is expected that a CPU will start executing 709 code directly at the right address, both on a cold and warm reset. In this 710 case, there is no need to identify the entrypoint on boot and the boot path 711 can be optimised. The ``plat_get_my_entrypoint()`` platform porting interface 712 does not need to be implemented in this case. 713 714- ``PSCI_EXTENDED_STATE_ID``: As per PSCI1.0 Specification, there are 2 formats 715 possible for the PSCI power-state parameter: original and extended State-ID 716 formats. This flag if set to 1, configures the generic PSCI layer to use the 717 extended format. The default value of this flag is 0, which means by default 718 the original power-state format is used by the PSCI implementation. This flag 719 should be specified by the platform makefile and it governs the return value 720 of PSCI_FEATURES API for CPU_SUSPEND smc function id. When this option is 721 enabled on Arm platforms, the option ``ARM_RECOM_STATE_ID_ENC`` needs to be 722 set to 1 as well. 723 724- ``RAS_EXTENSION``: Numeric value to enable Armv8.2 RAS features. RAS features 725 are an optional extension for pre-Armv8.2 CPUs, but are mandatory for Armv8.2 726 or later CPUs. This flag can take the values 0 to 2, to align with the 727 ``FEATURE_DETECTION`` mechanism. 728 729 When ``RAS_EXTENSION`` is set to ``1``, ``HANDLE_EA_EL3_FIRST_NS`` must also be 730 set to ``1``. 731 732 This option is disabled by default. 733 734- ``RESET_TO_BL31``: Enable BL31 entrypoint as the CPU reset vector instead 735 of the BL1 entrypoint. It can take the value 0 (CPU reset to BL1 736 entrypoint) or 1 (CPU reset to BL31 entrypoint). 737 The default value is 0. 738 739- ``RESET_TO_BL31_WITH_PARAMS``: If ``RESET_TO_BL31`` has been enabled, setting 740 this additional option guarantees that the input registers are not cleared 741 therefore allowing parameters to be passed to the BL31 entrypoint. 742 The default value is 0. 743 744- ``RESET_TO_SP_MIN``: SP_MIN is the minimal AArch32 Secure Payload provided 745 in TF-A. This flag configures SP_MIN entrypoint as the CPU reset vector 746 instead of the BL1 entrypoint. It can take the value 0 (CPU reset to BL1 747 entrypoint) or 1 (CPU reset to SP_MIN entrypoint). The default value is 0. 748 749- ``ROT_KEY``: This option is used when ``GENERATE_COT=1``. It specifies the 750 file that contains the ROT private key in PEM format and enforces public key 751 hash generation. If ``SAVE_KEYS=1``, this 752 file name will be used to save the key. 753 754- ``SAVE_KEYS``: This option is used when ``GENERATE_COT=1``. It tells the 755 certificate generation tool to save the keys used to establish the Chain of 756 Trust. Allowed options are '0' or '1'. Default is '0' (do not save). 757 758- ``SCP_BL2``: Path to SCP_BL2 image in the host file system. This image is optional. 759 If a SCP_BL2 image is present then this option must be passed for the ``fip`` 760 target. 761 762- ``SCP_BL2_KEY``: This option is used when ``GENERATE_COT=1``. It specifies the 763 file that contains the SCP_BL2 private key in PEM format. If ``SAVE_KEYS=1``, 764 this file name will be used to save the key. 765 766- ``SCP_BL2U``: Path to SCP_BL2U image in the host file system. This image is 767 optional. It is only needed if the platform makefile specifies that it 768 is required in order to build the ``fwu_fip`` target. 769 770- ``SDEI_SUPPORT``: Setting this to ``1`` enables support for Software 771 Delegated Exception Interface to BL31 image. This defaults to ``0``. 772 773 When set to ``1``, the build option ``EL3_EXCEPTION_HANDLING`` must also be 774 set to ``1``. 775 776- ``SEPARATE_CODE_AND_RODATA``: Whether code and read-only data should be 777 isolated on separate memory pages. This is a trade-off between security and 778 memory usage. See "Isolating code and read-only data on separate memory 779 pages" section in :ref:`Firmware Design`. This flag is disabled by default 780 and affects all BL images. 781 782- ``SEPARATE_NOBITS_REGION``: Setting this option to ``1`` allows the NOBITS 783 sections of BL31 (.bss, stacks, page tables, and coherent memory) to be 784 allocated in RAM discontiguous from the loaded firmware image. When set, the 785 platform is expected to provide definitions for ``BL31_NOBITS_BASE`` and 786 ``BL31_NOBITS_LIMIT``. When the option is ``0`` (the default), NOBITS 787 sections are placed in RAM immediately following the loaded firmware image. 788 789- ``SEPARATE_BL2_NOLOAD_REGION``: Setting this option to ``1`` allows the 790 NOLOAD sections of BL2 (.bss, stacks, page tables) to be allocated in RAM 791 discontiguous from loaded firmware images. When set, the platform need to 792 provide definitions of ``BL2_NOLOAD_START`` and ``BL2_NOLOAD_LIMIT``. This 793 flag is disabled by default and NOLOAD sections are placed in RAM immediately 794 following the loaded firmware image. 795 796- ``SMC_PCI_SUPPORT``: This option allows platforms to handle PCI configuration 797 access requests via a standard SMCCC defined in `DEN0115`_. When combined with 798 UEFI+ACPI this can provide a certain amount of OS forward compatibility 799 with newer platforms that aren't ECAM compliant. 800 801- ``SPD``: Choose a Secure Payload Dispatcher component to be built into TF-A. 802 This build option is only valid if ``ARCH=aarch64``. The value should be 803 the path to the directory containing the SPD source, relative to 804 ``services/spd/``; the directory is expected to contain a makefile called 805 ``<spd-value>.mk``. The SPM Dispatcher standard service is located in 806 services/std_svc/spmd and enabled by ``SPD=spmd``. The SPM Dispatcher 807 cannot be enabled when the ``SPM_MM`` option is enabled. 808 809- ``SPIN_ON_BL1_EXIT``: This option introduces an infinite loop in BL1. It can 810 take either 0 (no loop) or 1 (add a loop). 0 is the default. This loop stops 811 execution in BL1 just before handing over to BL31. At this point, all 812 firmware images have been loaded in memory, and the MMU and caches are 813 turned off. Refer to the "Debugging options" section for more details. 814 815- ``SPMC_AT_EL3`` : This boolean option is used jointly with the SPM 816 Dispatcher option (``SPD=spmd``). When enabled (1) it indicates the SPMC 817 component runs at the EL3 exception level. The default value is ``0`` ( 818 disabled). This configuration supports pre-Armv8.4 platforms (aka not 819 implementing the ``FEAT_SEL2`` extension). This is an experimental feature. 820 821- ``SPMD_SPM_AT_SEL2`` : This boolean option is used jointly with the SPM 822 Dispatcher option (``SPD=spmd``). When enabled (1) it indicates the SPMC 823 component runs at the S-EL2 exception level provided by the ``FEAT_SEL2`` 824 extension. This is the default when enabling the SPM Dispatcher. When 825 disabled (0) it indicates the SPMC component runs at the S-EL1 execution 826 state or at EL3 if ``SPMC_AT_EL3`` is enabled. The latter configurations 827 support pre-Armv8.4 platforms (aka not implementing the ``FEAT_SEL2`` 828 extension). 829 830- ``SPM_MM`` : Boolean option to enable the Management Mode (MM)-based Secure 831 Partition Manager (SPM) implementation. The default value is ``0`` 832 (disabled). This option cannot be enabled (``1``) when SPM Dispatcher is 833 enabled (``SPD=spmd``). 834 835- ``SP_LAYOUT_FILE``: Platform provided path to JSON file containing the 836 description of secure partitions. The build system will parse this file and 837 package all secure partition blobs into the FIP. This file is not 838 necessarily part of TF-A tree. Only available when ``SPD=spmd``. 839 840- ``SP_MIN_WITH_SECURE_FIQ``: Boolean flag to indicate the SP_MIN handles 841 secure interrupts (caught through the FIQ line). Platforms can enable 842 this directive if they need to handle such interruption. When enabled, 843 the FIQ are handled in monitor mode and non secure world is not allowed 844 to mask these events. Platforms that enable FIQ handling in SP_MIN shall 845 implement the api ``sp_min_plat_fiq_handler()``. The default value is 0. 846 847- ``SVE_VECTOR_LEN``: SVE vector length to configure in ZCR_EL3. 848 Platforms can configure this if they need to lower the hardware 849 limit, for example due to asymmetric configuration or limitations of 850 software run at lower ELs. The default is the architectural maximum 851 of 2048 which should be suitable for most configurations, the 852 hardware will limit the effective VL to the maximum physically supported 853 VL. 854 855- ``TRUSTED_BOARD_BOOT``: Boolean flag to include support for the Trusted Board 856 Boot feature. When set to '1', BL1 and BL2 images include support to load 857 and verify the certificates and images in a FIP, and BL1 includes support 858 for the Firmware Update. The default value is '0'. Generation and inclusion 859 of certificates in the FIP and FWU_FIP depends upon the value of the 860 ``GENERATE_COT`` option. 861 862 .. warning:: 863 This option depends on ``CREATE_KEYS`` to be enabled. If the keys 864 already exist in disk, they will be overwritten without further notice. 865 866- ``TRUSTED_WORLD_KEY``: This option is used when ``GENERATE_COT=1``. It 867 specifies the file that contains the Trusted World private key in PEM 868 format. If ``SAVE_KEYS=1``, this file name will be used to save the key. 869 870- ``TSP_INIT_ASYNC``: Choose BL32 initialization method as asynchronous or 871 synchronous, (see "Initializing a BL32 Image" section in 872 :ref:`Firmware Design`). It can take the value 0 (BL32 is initialized using 873 synchronous method) or 1 (BL32 is initialized using asynchronous method). 874 Default is 0. 875 876- ``TSP_NS_INTR_ASYNC_PREEMPT``: A non zero value enables the interrupt 877 routing model which routes non-secure interrupts asynchronously from TSP 878 to EL3 causing immediate preemption of TSP. The EL3 is responsible 879 for saving and restoring the TSP context in this routing model. The 880 default routing model (when the value is 0) is to route non-secure 881 interrupts to TSP allowing it to save its context and hand over 882 synchronously to EL3 via an SMC. 883 884 .. note:: 885 When ``EL3_EXCEPTION_HANDLING`` is ``1``, ``TSP_NS_INTR_ASYNC_PREEMPT`` 886 must also be set to ``1``. 887 888- ``TWED_DELAY``: Numeric value to be set in order to delay the trapping of 889 WFE instruction. ``ENABLE_FEAT_TWED`` build option must be enabled to set 890 this delay. It can take values in the range (0-15). Default value is ``0`` 891 and based on this value, 2^(TWED_DELAY + 8) cycles will be delayed. 892 Platforms need to explicitly update this value based on their requirements. 893 894- ``USE_ARM_LINK``: This flag determines whether to enable support for ARM 895 linker. When the ``LINKER`` build variable points to the armlink linker, 896 this flag is enabled automatically. To enable support for armlink, platforms 897 will have to provide a scatter file for the BL image. Currently, Tegra 898 platforms use the armlink support to compile BL3-1 images. 899 900- ``USE_COHERENT_MEM``: This flag determines whether to include the coherent 901 memory region in the BL memory map or not (see "Use of Coherent memory in 902 TF-A" section in :ref:`Firmware Design`). It can take the value 1 903 (Coherent memory region is included) or 0 (Coherent memory region is 904 excluded). Default is 1. 905 906- ``USE_DEBUGFS``: When set to 1 this option activates an EXPERIMENTAL feature 907 exposing a virtual filesystem interface through BL31 as a SiP SMC function. 908 Default is 0. 909 910- ``ARM_IO_IN_DTB``: This flag determines whether to use IO based on the 911 firmware configuration framework. This will move the io_policies into a 912 configuration device tree, instead of static structure in the code base. 913 914- ``COT_DESC_IN_DTB``: This flag determines whether to create COT descriptors 915 at runtime using fconf. If this flag is enabled, COT descriptors are 916 statically captured in tb_fw_config file in the form of device tree nodes 917 and properties. Currently, COT descriptors used by BL2 are moved to the 918 device tree and COT descriptors used by BL1 are retained in the code 919 base statically. 920 921- ``SDEI_IN_FCONF``: This flag determines whether to configure SDEI setup in 922 runtime using firmware configuration framework. The platform specific SDEI 923 shared and private events configuration is retrieved from device tree rather 924 than static C structures at compile time. This is only supported if 925 SDEI_SUPPORT build flag is enabled. 926 927- ``SEC_INT_DESC_IN_FCONF``: This flag determines whether to configure Group 0 928 and Group1 secure interrupts using the firmware configuration framework. The 929 platform specific secure interrupt property descriptor is retrieved from 930 device tree in runtime rather than depending on static C structure at compile 931 time. 932 933- ``USE_ROMLIB``: This flag determines whether library at ROM will be used. 934 This feature creates a library of functions to be placed in ROM and thus 935 reduces SRAM usage. Refer to :ref:`Library at ROM` for further details. Default 936 is 0. 937 938- ``V``: Verbose build. If assigned anything other than 0, the build commands 939 are printed. Default is 0. 940 941- ``VERSION_STRING``: String used in the log output for each TF-A image. 942 Defaults to a string formed by concatenating the version number, build type 943 and build string. 944 945- ``W``: Warning level. Some compiler warning options of interest have been 946 regrouped and put in the root Makefile. This flag can take the values 0 to 3, 947 each level enabling more warning options. Default is 0. 948 949- ``WARMBOOT_ENABLE_DCACHE_EARLY`` : Boolean option to enable D-cache early on 950 the CPU after warm boot. This is applicable for platforms which do not 951 require interconnect programming to enable cache coherency (eg: single 952 cluster platforms). If this option is enabled, then warm boot path 953 enables D-caches immediately after enabling MMU. This option defaults to 0. 954 955- ``SUPPORT_STACK_MEMTAG``: This flag determines whether to enable memory 956 tagging for stack or not. It accepts 2 values: ``yes`` and ``no``. The 957 default value of this flag is ``no``. Note this option must be enabled only 958 for ARM architecture greater than Armv8.5-A. 959 960- ``ERRATA_SPECULATIVE_AT``: This flag determines whether to enable ``AT`` 961 speculative errata workaround or not. It accepts 2 values: ``1`` and ``0``. 962 The default value of this flag is ``0``. 963 964 ``AT`` speculative errata workaround disables stage1 page table walk for 965 lower ELs (EL1 and EL0) in EL3 so that ``AT`` speculative fetch at any point 966 produces either the correct result or failure without TLB allocation. 967 968 This boolean option enables errata for all below CPUs. 969 970 +---------+--------------+-------------------------+ 971 | Errata | CPU | Workaround Define | 972 +=========+==============+=========================+ 973 | 1165522 | Cortex-A76 | ``ERRATA_A76_1165522`` | 974 +---------+--------------+-------------------------+ 975 | 1319367 | Cortex-A72 | ``ERRATA_A72_1319367`` | 976 +---------+--------------+-------------------------+ 977 | 1319537 | Cortex-A57 | ``ERRATA_A57_1319537`` | 978 +---------+--------------+-------------------------+ 979 | 1530923 | Cortex-A55 | ``ERRATA_A55_1530923`` | 980 +---------+--------------+-------------------------+ 981 | 1530924 | Cortex-A53 | ``ERRATA_A53_1530924`` | 982 +---------+--------------+-------------------------+ 983 984 .. note:: 985 This option is enabled by build only if platform sets any of above defines 986 mentioned in ’Workaround Define' column in the table. 987 If this option is enabled for the EL3 software then EL2 software also must 988 implement this workaround due to the behaviour of the errata mentioned 989 in new SDEN document which will get published soon. 990 991- ``RAS_TRAP_NS_ERR_REC_ACCESS``: This flag enables/disables the SCR_EL3.TERR 992 bit, to trap access to the RAS ERR and RAS ERX registers from lower ELs. 993 This flag is disabled by default. 994 995- ``OPENSSL_DIR``: This option is used to provide the path to a directory on the 996 host machine where a custom installation of OpenSSL is located, which is used 997 to build the certificate generation, firmware encryption and FIP tools. If 998 this option is not set, the default OS installation will be used. 999 1000- ``USE_SP804_TIMER``: Use the SP804 timer instead of the Generic Timer for 1001 functions that wait for an arbitrary time length (udelay and mdelay). The 1002 default value is 0. 1003 1004- ``ENABLE_BRBE_FOR_NS``: Numeric value to enable access to the branch record 1005 buffer registers from NS ELs when FEAT_BRBE is implemented. BRBE is an 1006 optional architectural feature for AArch64. This flag can take the values 1007 0 to 2, to align with the ``FEATURE_DETECTION`` mechanism. The default is 0 1008 and it is automatically disabled when the target architecture is AArch32. 1009 1010- ``ENABLE_TRBE_FOR_NS``: Numeric value to enable access of trace buffer 1011 control registers from NS ELs, NS-EL2 or NS-EL1(when NS-EL2 is implemented 1012 but unused) when FEAT_TRBE is implemented. TRBE is an optional architectural 1013 feature for AArch64. This flag can take the values 0 to 2, to align with the 1014 ``FEATURE_DETECTION`` mechanism. The default is 0 and it is automatically 1015 disabled when the target architecture is AArch32. 1016 1017- ``ENABLE_SYS_REG_TRACE_FOR_NS``: Boolean option to enable trace system 1018 registers access from NS ELs, NS-EL2 or NS-EL1 (when NS-EL2 is implemented 1019 but unused). This feature is available if trace unit such as ETMv4.x, and 1020 ETE(extending ETM feature) is implemented. This flag is disabled by default. 1021 1022- ``ENABLE_TRF_FOR_NS``: Numeric value to enable trace filter control registers 1023 access from NS ELs, NS-EL2 or NS-EL1 (when NS-EL2 is implemented but unused), 1024 if FEAT_TRF is implemented. This flag can take the values 0 to 2, to align 1025 with the ``FEATURE_DETECTION`` mechanism. This flag is disabled by default. 1026 1027- ``PLAT_RSS_NOT_SUPPORTED``: Boolean option to enable the usage of the PSA 1028 APIs on platforms that doesn't support RSS (providing Arm CCA HES 1029 functionalities). When enabled (``1``), a mocked version of the APIs are used. 1030 The default value is 0. 1031 1032GICv3 driver options 1033-------------------- 1034 1035GICv3 driver files are included using directive: 1036 1037``include drivers/arm/gic/v3/gicv3.mk`` 1038 1039The driver can be configured with the following options set in the platform 1040makefile: 1041 1042- ``GICV3_SUPPORT_GIC600``: Add support for the GIC-600 variants of GICv3. 1043 Enabling this option will add runtime detection support for the 1044 GIC-600, so is safe to select even for a GIC500 implementation. 1045 This option defaults to 0. 1046 1047- ``GICV3_SUPPORT_GIC600AE_FMU``: Add support for the Fault Management Unit 1048 for GIC-600 AE. Enabling this option will introduce support to initialize 1049 the FMU. Platforms should call the init function during boot to enable the 1050 FMU and its safety mechanisms. This option defaults to 0. 1051 1052- ``GICV3_IMPL_GIC600_MULTICHIP``: Selects GIC-600 variant with multichip 1053 functionality. This option defaults to 0 1054 1055- ``GICV3_OVERRIDE_DISTIF_PWR_OPS``: Allows override of default implementation 1056 of ``arm_gicv3_distif_pre_save`` and ``arm_gicv3_distif_post_restore`` 1057 functions. This is required for FVP platform which need to simulate GIC save 1058 and restore during SYSTEM_SUSPEND without powering down GIC. Default is 0. 1059 1060- ``GIC_ENABLE_V4_EXTN`` : Enables GICv4 related changes in GICv3 driver. 1061 This option defaults to 0. 1062 1063- ``GIC_EXT_INTID``: When set to ``1``, GICv3 driver will support extended 1064 PPI (1056-1119) and SPI (4096-5119) range. This option defaults to 0. 1065 1066Debugging options 1067----------------- 1068 1069To compile a debug version and make the build more verbose use 1070 1071.. code:: shell 1072 1073 make PLAT=<platform> DEBUG=1 V=1 all 1074 1075AArch64 GCC 11 uses DWARF version 5 debugging symbols by default. Some tools 1076(for example Arm-DS) might not support this and may need an older version of 1077DWARF symbols to be emitted by GCC. This can be achieved by using the 1078``-gdwarf-<version>`` flag, with the version being set to 2, 3, 4 or 5. Setting 1079the version to 4 is recommended for Arm-DS. 1080 1081When debugging logic problems it might also be useful to disable all compiler 1082optimizations by using ``-O0``. 1083 1084.. warning:: 1085 Using ``-O0`` could cause output images to be larger and base addresses 1086 might need to be recalculated (see the **Memory layout on Arm development 1087 platforms** section in the :ref:`Firmware Design`). 1088 1089Extra debug options can be passed to the build system by setting ``CFLAGS`` or 1090``LDFLAGS``: 1091 1092.. code:: shell 1093 1094 CFLAGS='-O0 -gdwarf-2' \ 1095 make PLAT=<platform> DEBUG=1 V=1 all 1096 1097Note that using ``-Wl,`` style compilation driver options in ``CFLAGS`` will be 1098ignored as the linker is called directly. 1099 1100It is also possible to introduce an infinite loop to help in debugging the 1101post-BL2 phase of TF-A. This can be done by rebuilding BL1 with the 1102``SPIN_ON_BL1_EXIT=1`` build flag. Refer to the :ref:`build_options_common` 1103section. In this case, the developer may take control of the target using a 1104debugger when indicated by the console output. When using Arm-DS, the following 1105commands can be used: 1106 1107:: 1108 1109 # Stop target execution 1110 interrupt 1111 1112 # 1113 # Prepare your debugging environment, e.g. set breakpoints 1114 # 1115 1116 # Jump over the debug loop 1117 set var $AARCH64::$Core::$PC = $AARCH64::$Core::$PC + 4 1118 1119 # Resume execution 1120 continue 1121 1122Firmware update options 1123----------------------- 1124 1125- ``NR_OF_FW_BANKS``: Define the number of firmware banks. This flag is used 1126 in defining the firmware update metadata structure. This flag is by default 1127 set to '2'. 1128 1129- ``NR_OF_IMAGES_IN_FW_BANK``: Define the number of firmware images in each 1130 firmware bank. Each firmware bank must have the same number of images as per 1131 the `PSA FW update specification`_. 1132 This flag is used in defining the firmware update metadata structure. This 1133 flag is by default set to '1'. 1134 1135- ``PSA_FWU_SUPPORT``: Enable the firmware update mechanism as per the 1136 `PSA FW update specification`_. The default value is 0, and this is an 1137 experimental feature. 1138 PSA firmware update implementation has some limitations, such as BL2 is 1139 not part of the protocol-updatable images, if BL2 needs to be updated, then 1140 it should be done through another platform-defined mechanism, and it assumes 1141 that the platform's hardware supports CRC32 instructions. 1142 1143-------------- 1144 1145*Copyright (c) 2019-2022, Arm Limited. All rights reserved.* 1146 1147.. _DEN0115: https://developer.arm.com/docs/den0115/latest 1148.. _PSA FW update specification: https://developer.arm.com/documentation/den0118/a/ 1149.. _PSA DRTM specification: https://developer.arm.com/documentation/den0113/a 1150