-------------- NXP Platforms: -------------- TRUSTED_BOARD_BOOT option can be enabled by specifying TRUSTED_BOARD_BOOT=1 on command line during make. Bare-Minimum Preparation to run TBBR on NXP Platforms: ======================================================= - OTPMK(One Time Programable Key) needs to be burnt in fuses. -- It is the 256 bit key that stores a secret value used by the NXP SEC 4.0 IP in Trusted or Secure mode. Note: It is primarily for the purpose of decrypting additional secrets stored in system non-volatile memory. -- NXP CST tool gives an option to generate it. Use the below command from directory 'cst', with correct options. .. code:: shell ./gen_otpmk_drbg - SRKH (Super Root Key Hash) needs to be burnt in fuses. -- It is the 256 bit hash of the list of the public keys of the SRK key pair. -- NXP CST tool gives an option to generate the RSA key pair and its hash. Use the below command from directory 'cst', with correct options. .. code:: shell ./gen_keys Refer fuse frovisioning readme 'nxp-ls-fuse-prov.rst' for steps to blow these keys. Two options are provided for TRUSTED_BOARD_BOOT: ================================================ ------------------------------------------------------------------------- Option 1: CoT using X 509 certificates ------------------------------------------------------------------------- - This CoT is as provided by ARM. - To use this option user needs to specify mbedtld dir path in MBEDTLS_DIR. - To generate CSF header, path of CST repository needs to be specified as CST_DIR - CSF header is embedded to each of the BL2 image. - GENERATE_COT=1 adds the tool 'cert_create' to the build environment to generate: -- X509 Certificates as (.crt) files. -- X509 Pem key file as (.pem) files. - SAVE_KEYS=1 saves the keys and certificates, if GENERATE_COT=1. -- For this to work, file name for cert and keys are provided as part of compilation or build command. --- default file names will be used, incase not provided as part compilation or build command. --- default folder 'BUILD_PLAT' will be used to store them. - ROTPK for x.509 certificates is generated and embedded in bl2.bin and verified as part of CoT by Boot ROM during secure boot. - Compilation steps: All Images .. code:: shell make PLAT=$PLAT TRUSTED_BOARD_BOOT=1 GENERATE_COT=1 MBEDTLS_DIR=$MBEDTLS_PATH CST_DIR=$CST_DIR_PATH \ BOOT_MODE= \ RCW=$RCW_BIN \ BL32=$TEE_BIN SPD=opteed\ BL33=$UBOOT_SECURE_BIN \ pbl \ fip Additional FIP_DDR Image (For NXP platforms like lx2160a) .. code:: shell make PLAT=$PLAT TRUSTED_BOARD_BOOT=1 GENERATE_COT=1 MBEDTLS_DIR=$MBEDTLS_PATH fip_ddr Note: make target 'fip_ddr' should never be combine with other make target 'fip', 'pbl' & 'bl2'. ------------------------------------------------------------------------- Option 2: CoT using NXP CSF headers. ------------------------------------------------------------------------- - This option is automatically selected when TRUSTED_BOARD_BOOT is set but MBEDTLS_DIR path is not specified. - CSF header is embedded to each of the BL31, BL32 and BL33 image. - To generate CSF header, path of CST repository needs to be specified as CST_DIR - Default input files for CSF header generation is added in this repo. - Default input file requires user to generate RSA key pair named -- srk.pri, and -- srk.pub, and add them in ATF repo. -- These keys can be generated using gen_keys tool of CST. - To change the input file , user can use the options BL33_INPUT_FILE, BL32_INPUT_FILE, BL31_INPUT_FILE - There are 2 paths in secure boot flow : -- Development Mode (sb_en in RCW = 1, SFP->OSPR, ITS = 0) --- In this flow , even on ROTPK comparison failure, flow would continue. --- However SNVS is transitioned to non-secure state -- Production mode (SFP->OSPR, ITS = 1) --- Any failure is fatal failure - Compilation steps: All Images .. code:: shell make PLAT=$PLAT TRUSTED_BOARD_BOOT=1 CST_DIR=$CST_DIR_PATH \ BOOT_MODE= \ RCW=$RCW_BIN \ BL32=$TEE_BIN SPD=opteed\ BL33=$UBOOT_SECURE_BIN \ pbl \ fip Additional FIP_DDR Image (For NXP platforms like lx2160a) .. code:: shell make PLAT=$PLAT TRUSTED_BOARD_BOOT=1 CST_DIR=$CST_DIR_PATH fip_ddr - Compilation Steps with build option for generic image processing filters to prepend CSF header: -- Generic image processing filters to prepend CSF header BL32_INPUT_FILE = < file name> BL33_INPUT_FILE = .. code:: shell make PLAT=$PLAT TRUSTED_BOARD_BOOT=1 CST_DIR=$CST_DIR_PATH \ BOOT_MODE= \ RCW=$RCW_BIN \ BL32=$TEE_BIN SPD=opteed\ BL33=$UBOOT_SECURE_BIN \ BL33_INPUT_FILE = \ BL32_INPUT_FILE = \ BL31_INPUT_FILE = \ pbl \ fip Deploy ATF Images ================= Same steps as mentioned in the readme "nxp-layerscape.rst". Verification to check if Secure state is achieved: ================================================== +---+----------------+-----------------+------------------------+----------------------------------+-------------------------------+ | | Platform | SNVS_HPSR_REG | SYS_SECURE_BIT(=value) | SYSTEM_SECURE_CONFIG_BIT(=value) | SSM_STATE | +===+================+=================+========================+==================================+===============================+ | 1.| lx2160ardb or | 0x01E90014 | 15 | 14-12 | 11-8 | | | lx2160aqds or | | ( = 1, BootROM Booted) | ( = 010 means Intent to Secure, | (=1111 means secure boot) | | | lx2162aqds | | | ( = 000 Unsecure) | (=1011 means Non-secure Boot) | +---+----------------+-----------------+------------------------+----------------------------------+-------------------------------+ - Production mode (SFP->OSPR, ITS = 1) -- Linux prompt will successfully come. if the TBBR is successful. --- Else, Linux boot will be successful. -- For secure-boot status, read SNVS Register $SNVS_HPSR_REG from u-boot prompt: .. code:: shell md $SNVS_HPSR_REG Command Output: 1e90014: 8000AF00 In case it is read as 00000000, then read this register using jtag (in development mode only through CW tap). +0 +4 +8 +C [0x01E90014] 8000AF00 - Development Mode (sb_en in RCW = 1, SFP->OSPR, ITS = 0) -- Refer the SoC specific table to read the register to interpret whether the secure boot is achieved or not. -- Using JTAG (in development environment only, using CW tap): --- For secure-boot status, read SNVS Register $SNVS_HPSR_REG .. code:: shell ccs::display_regs 86 0x01E90014 4 0 1 Command Output: Using the SAP chain position number 86, following is the output. +0 +4 +8 +C [0x01E90014] 8000AF00 Note: Chain position number will vary from one SoC to other SoC. - Interpretation of the value: -- 0xA indicates BootROM booted, with intent to secure. -- 0xF = secure boot, as SSM_STATE.