doc: uefi.rst: Add OP-TEE variable storage config options

If OP-TEE is compiled with an EDK2 application running in secure world
it can process and store UEFI variables in an RPMB.
Add documentation for the config options enabling this.

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
This commit is contained in:
Ilias Apalodimas 2020-05-17 22:25:47 +03:00 committed by Heinrich Schuchardt
parent e4acbe4e34
commit e498dac43e

View File

@ -188,6 +188,23 @@ on the sandbox
cd <U-Boot source directory>
pytest.py test/py/tests/test_efi_secboot/test_signed.py --bd sandbox
Using OP-TEE for EFI variables
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Instead of implementing UEFI variable services inside U-Boot they can
also be provided in the secure world by a module for OP-TEE[1]. The
interface between U-Boot and OP-TEE for variable services is enabled by
CONFIG_EFI_MM_COMM_TEE=y.
Tianocore EDK II's standalone management mode driver for variables can
be linked to OP-TEE for this purpose. This module uses the Replay
Protected Memory Block (RPMB) of an eMMC device for persisting
non-volatile variables. When calling the variable services via the
OP-TEE API U-Boot's OP-TEE supplicant relays calls to the RPMB driver
which has to be enabled via CONFIG_SUPPORT_EMMC_RPMB=y.
[1] https://optee.readthedocs.io/ - OP-TEE documentation
Executing the boot manager
~~~~~~~~~~~~~~~~~~~~~~~~~~