u-boot/doc/README.mxc_hab
Stefano Babic 0187c985aa tools: add support for setting the CSF into imximage
Add support for setting the CSF (Command Sequence File) pointer
which is used for HAB (High Assurance Boot) in the imximage by
adding e.g.

CSF 0x2000

in the imximage.cfg file.

This will set the CSF pointer accordingly just after the padded
data image area. The boot_data.length is adjusted with the
value from the imximage.cfg config file.

The resulting u-boot.imx can be signed with the FSL HAB tooling.
The generated CSF block needs to be appended to the u-boot.imx.

Signed-off-by: Stefano Babic <sbabic@denx.de>
2013-08-31 15:06:29 +02:00

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High Assurance Boot (HAB) for i.MX6 CPUs
To authenticate U-Boot only by the CPU there is no code required in
U-Boot itself. However, the U-Boot image to be programmed into the
boot media needs to be properly constructed, i.e. it must contain a
proper Command Sequence File (CSF).
The Initial Vector Table contains a pointer to the CSF. Please see
doc/README.imximage for how to prepare u-boot.imx.
The CSF itself is being generated by Freescale HAB tools.
mkimage will output additional information about "HAB Blocks"
which can be used in the Freescale tooling to authenticate U-Boot
(entries in the CSF file).
Image Type: Freescale IMX Boot Image
Image Ver: 2 (i.MX53/6 compatible)
Data Size: 327680 Bytes = 320.00 kB = 0.31 MB
Load Address: 177ff420
Entry Point: 17800000
HAB Blocks: 177ff400 00000000 0004dc00
^^^^^^^^ ^^^^^^^^ ^^^^^^^^
| | |
| | -------- (1)
| |
| ------------------- (2)
|
--------------------------- (3)
(1) Size of area in file u-boot.imx to sign
This area should include the IVT, the Boot Data the DCD
and U-Boot itself.
(2) Start of area in u-boot.imx to sign
(3) Start of area in RAM to authenticate
CONFIG_SECURE_BOOT currently enables only an additional command
'hab_status' in U-Boot to retrieve the HAB status and events. This
can be useful while developing and testing HAB.
Commands to generate a signed U-Boot using Freescale HAB tools:
cst --o U-Boot_CSF.bin < U-Boot.CSF
objcopy -I binary -O binary --pad-to 0x2000 --gap-fill=0x00 \
U-Boot_CSF.bin U-Boot_CSF_pad.bin
cat u-boot.imx U-Boot_CSF_pad.bin > u-boot-signed.imx
NOTE: U-Boot_CSF.bin needs to be padded to the value specified in
the imximage.cfg file.