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 --- doc/uefi/uefi.rst | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/doc/uefi/uefi.rst b/doc/uefi/uefi.rst index 4fda00d68721..03d6fd0c6aa8 100644 --- a/doc/uefi/uefi.rst +++ b/doc/uefi/uefi.rst @@ -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 ~~~~~~~~~~~~~~~~~~~~~~~~~~