On modern Qualcomm platforms, access to EFI variables is restricted to the secure world / TrustZone, i.e. the Trusted Execution Environment (TrEE or TEE) as Qualcomm seems to call it. To access EFI variables, we therefore need to talk to the UEFI Secure Application (uefisecapp), residing in the TrEE. This series adds support for accessing EFI variables on those platforms. To do this, we first need to add some SCM call functions used to manage and talk to Secure Applications. A very small subset of this interface is added in the second patch (whereas the first one exports the required functions for that). Interface specifications are extracted from [1]. While this does not (yet) support re-entrant SCM calls (including callbacks and listeners), this is enough to talk to the aforementioned uefisecapp on a couple of platforms (I've tested this on a Surface Pro X and heard reports from Lenovo Flex 5G, Lenovo Thinkpad x13s, and Lenovo Yoga C630 devices). The third patch adds a client driver for uefisecapp, installing the respective efivar operations. The application interface has been reverse engineered from the Windows QcTrEE8180.sys driver. Apart from uefisecapp, there are more Secure Applications running that we might want to support in the future. For example, on the Surface Pro X (sc8180x-based), the TPM is also managed via one. I'm not sure whether this should go to drivers/firmware or to drivers/soc/qcom. I've put this into firmware as all of this is essentially an interface to the secure firmware running in the TrustZone (and SCM stuff is handled here already), but please let me know if I should move this. Regards, Max [1]: https://git.codelinaro.org/clo/la/kernel/msm-4.14/-/blob/auto-kernel.lnx.4.14.c34/drivers/misc/qseecom.c Maximilian Luz (4): firmware: qcom_scm: Export SCM call functions firmware: Add support for Qualcomm Trusted Execution Environment SCM calls firmware: Add support for Qualcomm UEFI Secure Application dt-bindings: firmware: Add Qualcomm UEFI Secure Application client .../firmware/qcom,tee-uefisecapp.yaml | 38 + MAINTAINERS | 14 + drivers/firmware/Kconfig | 20 + drivers/firmware/Makefile | 2 + drivers/firmware/qcom_scm.c | 118 ++- drivers/firmware/qcom_scm.h | 47 -- drivers/firmware/qcom_tee.c | 213 +++++ drivers/firmware/qcom_tee_uefisecapp.c | 761 ++++++++++++++++++ include/linux/qcom_scm.h | 49 ++ include/linux/qcom_tee.h | 179 ++++ 10 files changed, 1355 insertions(+), 86 deletions(-) create mode 100644 Documentation/devicetree/bindings/firmware/qcom,tee-uefisecapp.yaml create mode 100644 drivers/firmware/qcom_tee.c create mode 100644 drivers/firmware/qcom_tee_uefisecapp.c create mode 100644 include/linux/qcom_tee.h -- 2.37.1
