| Stefano Babic | 4aa9749 | 2013-06-27 11:42:38 +0200 | [diff] [blame] | 1 | High Assurance Boot (HAB) for i.MX6 CPUs |
| 2 | |
| 3 | To authenticate U-Boot only by the CPU there is no code required in |
| 4 | U-Boot itself. However, the U-Boot image to be programmed into the |
| 5 | boot media needs to be properly constructed, i.e. it must contain a |
| 6 | proper Command Sequence File (CSF). |
| 7 | |
| 8 | The Initial Vector Table contains a pointer to the CSF. Please see |
| 9 | doc/README.imximage for how to prepare u-boot.imx. |
| 10 | |
| 11 | The CSF itself is being generated by Freescale HAB tools. |
| 12 | |
| 13 | mkimage will output additional information about "HAB Blocks" |
| 14 | which can be used in the Freescale tooling to authenticate U-Boot |
| 15 | (entries in the CSF file). |
| 16 | |
| 17 | Image Type: Freescale IMX Boot Image |
| 18 | Image Ver: 2 (i.MX53/6 compatible) |
| 19 | Data Size: 327680 Bytes = 320.00 kB = 0.31 MB |
| 20 | Load Address: 177ff420 |
| 21 | Entry Point: 17800000 |
| 22 | HAB Blocks: 177ff400 00000000 0004dc00 |
| Wolfgang Denk | ec7fbf5 | 2013-10-04 17:43:24 +0200 | [diff] [blame^] | 23 | ^^^^^^^^ ^^^^^^^^ ^^^^^^^^ |
| Stefano Babic | 4aa9749 | 2013-06-27 11:42:38 +0200 | [diff] [blame] | 24 | | | | |
| 25 | | | -------- (1) |
| 26 | | | |
| 27 | | ------------------- (2) |
| 28 | | |
| 29 | --------------------------- (3) |
| 30 | |
| 31 | (1) Size of area in file u-boot.imx to sign |
| 32 | This area should include the IVT, the Boot Data the DCD |
| 33 | and U-Boot itself. |
| 34 | (2) Start of area in u-boot.imx to sign |
| 35 | (3) Start of area in RAM to authenticate |
| 36 | |
| 37 | CONFIG_SECURE_BOOT currently enables only an additional command |
| 38 | 'hab_status' in U-Boot to retrieve the HAB status and events. This |
| 39 | can be useful while developing and testing HAB. |
| 40 | |
| 41 | Commands to generate a signed U-Boot using Freescale HAB tools: |
| 42 | cst --o U-Boot_CSF.bin < U-Boot.CSF |
| 43 | objcopy -I binary -O binary --pad-to 0x2000 --gap-fill=0x00 \ |
| 44 | U-Boot_CSF.bin U-Boot_CSF_pad.bin |
| 45 | cat u-boot.imx U-Boot_CSF_pad.bin > u-boot-signed.imx |
| 46 | |
| 47 | NOTE: U-Boot_CSF.bin needs to be padded to the value specified in |
| 48 | the imximage.cfg file. |