Trusted Firmware-A for i.MX7 WaRP7 ================================== The Trusted Firmware-A port for the i.MX7Solo WaRP7 implements BL2 at EL3. The i.MX7S contains a BootROM with a High Assurance Boot (HAB) functionality. This functionality provides a mechanism for establishing a root-of-trust from the reset vector to the command-line in user-space. Boot Flow ========= BootROM --> TF-A BL2 --> BL32(OP-TEE) --> BL33(U-Boot) --> Linux In the WaRP7 port we encapsulate OP-TEE, DTB and U-Boot into a FIP. This FIP is expected and required # Build Instructions We need to use a file generated by u-boot in order to generate a .imx image the BootROM will boot. It is therefore _required_ to build u-boot before TF-A and furthermore it is _recommended_ to use the mkimage in the u-boot/tools directory to generate the TF-A .imx image. ## U-Boot: https://git.linaro.org/landing-teams/working/mbl/u-boot.git .. code:: shell git checkout -b rms-atf-optee-uboot linaro-mbl/rms-atf-optee-uboot make warp7_bl33_defconfig; make u-boot.imx arch=ARM CROSS_COMPILE=arm-linux-gnueabihf- ## TF-A: https://github.com/ARM-software/arm-trusted-firmware.git .. code:: shell make CROSS_COMPILE=arm-linux-gnueabihf- PLAT=warp7 ARCH=aarch32 ARM_ARCH_MAJOR=7 ARM_CORTEX_A7=yes AARCH32_SP=optee all /path/to/u-boot/tools/mkimage -n /path/to/u-boot/u-boot.cfgout -T imximage -e 0x9df00000 -d ./build/warp7/debug/bl2.bin ./build/warp7/debug/bl2.bin.imx ## OP-TEE: https://github.com/OP-TEE/optee_os.git .. code:: shell make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- PLATFORM=imx PLATFORM_FLAVOR=mx7swarp7 ARCH=arm CFG_PAGEABLE_ADDR=0 CFG_DT_ADDR=0x83000000 CFG_NS_ENTRY_ADDR=0x87800000 ## FIP: .. code:: shell mkdir fiptool_images cp /path/to/uboot/u-boot.bin fiptool_images cp /path/to/optee/out/arm-plat-imx/core/tee-header_v2.bin fiptool_images cp /path/to/optee/out/arm-plat-imx/core/tee-pager_v2.bin fiptool_images cp /path/to/optee/out/arm-plat-imx/core/tee-pageable_v2.bin fiptool_images cp /path/to/linux/arch/boot/dts/imx7s-warp.dtb fiptool_images tools/fiptool/fiptool create --tos-fw fiptool_images/tee-header_v2.bin --tos-fw-extra1 fiptool_images/tee-pager_v2.bin --tos-fw-extra2 fiptool_images/tee-pageable_v2.bin --nt-fw fiptool_images/u-boot.bin --hw-config fiptool_images/imx7s-warp.dtb warp7.fip # Deploy Images First place the WaRP7 into UMS mode in u-boot this should produce an entry in /dev like /dev/disk/by-id/usb-Linux_UMS_disk_0_WaRP7-0xf42400d3000001d4-0\:0 .. code:: shell => ums 0 mmc 0 Next flash bl2.imx and warp7.fip bl2.imx is flashed @ 1024 bytes warp7.fip is flash @ 1048576 bytes .. code:: shell sudo dd if=bl2.bin.imx of=/dev/disk/by-id/usb-Linux_UMS_disk_0_WaRP7-0xf42400d3000001d4-0\:0 bs=512 seek=2 conv=notrunc # Offset is 1MB 1048576 => 1048576 / 512 = 2048 sudo dd if=./warp7.fip of=/dev/disk/by-id/usb-Linux_UMS_disk_0_WaRP7-0xf42400d3000001d4-0\:0 bs=512 seek=2048 conv=notrunc Remember to umount the USB device pefore proceeding .. code:: shell sudo umount /dev/disk/by-id/usb-Linux_UMS_disk_0_WaRP7-0xf42400d3000001d4-0\:0* # Signing BL2 A further step is to sign BL2. The image_sign.sh and bl2_sign.csf files alluded to blow are available here. https://github.com/bryanodonoghue/atf-code-signing It is suggested you use this script plus the example CSF file in order to avoid hard-coding data into your CSF files. Download both "image_sign.sh" and "bl2_sign.csf" to your arm-trusted-firmware top-level directory. .. code:: shell #!/bin/bash SIGN=image_sign.sh TEMP=`pwd`/temp BL2_CSF=bl2_sign.csf BL2_IMX=bl2.bin.imx CST_PATH=/path/to/cst-2.3.2 CST_BIN=${CST_PATH}/linux64/cst #Remove temp rm -rf ${TEMP} mkdir ${TEMP} # Generate IMX header /path/to/u-boot/tools/mkimage -n u-boot.cfgout.warp7 -T imximage -e 0x9df00000 -d ./build/warp7/debug/bl2.bin ./build/warp7/debug/bl2.bin.imx > ${TEMP}/${BL2_IMX}.log # Copy required items to $TEMP cp build/warp7/debug/bl2.bin.imx ${TEMP} cp ${CST_PATH}/keys/* ${TEMP} cp ${CST_PATH}/crts/* ${TEMP} cp ${BL2_CSF} ${TEMP} # Generate signed BL2 image ./${SIGN} image_sign_mbl_binary ${TEMP} ${BL2_CSF} ${BL2_IMX} ${CST_BIN} # Copy signed BL2 to top-level directory cp ${TEMP}/${BL2_IMX}-signed . cp ${BL2_RECOVER_CSF} ${TEMP} The resulting bl2.bin.imx-signed can replace bl2.bin.imx in the Deploy Images section above, once done. Suggested flow for verifying. 1. Followed all previous steps above and verify a non-secure ATF boot 2. Down the NXP Code Singing Tool 3. Generate keys 4. Program the fuses on your board 5. Replace bl2.bin.imx with bl2.bin.imx-signed 6. Verify inside u-boot that "hab_status" shows no events 7. Subsequently close your board. If you have HAB events @ step 6 - do not lock your board. To get a good over-view of generating keys and programming the fuses on the board read "High Assurance Boot for Dummies" by Boundary Devices. https://boundarydevices.com/high-assurance-boot-hab-dummies/