OP-TEE Linux Driver - **DEPRECATED**
2016-04-17: Driver has been deprecated
Since the release of OP-TEE 2.0.0, we are no longer using this OP-TEE Linux kernel driver, but we will keep it here for reference in case anyone needs it for one or another reason. Also, this version of the OP-TEE driver is not compatible with OP-TEE 2.0.0 and later. I.e, you cannot use this with latest on the other OP-TEE gits like optee_os, optee_client, optee_test etc.
The new driver we are using is located here: linaro-swg/linux/tree/optee. Hopefully we will get this driver mainlined at some point in time, but for the time being that will be our default OP-TEE driver for OP-TEE >= v2.0.0.
Another important patch that has been mainlined and is needed on older kernels is the ARM SMCCC patch that could be found here: [14457459f9ca2ff8521686168ea179edc3a56a44] (https://github.com/torvalds/linux/commit/14457459f9ca2ff8521686168ea179edc3a56a44)
The optee_linuxdriver git, containing the source code for the TEE driver module in Linux. It is distributed under the GPLv2 open-source license. For a general overview of OP-TEE, please see the Notice.md file.
In this git, the module to build is optee.ko. It allows communication between the Rich OS Client Application (unsecure world), the Trusted OS (secure world) and the tee-supplicant (unsecure world) which is a daemon serving the Trusted OS in secure world with miscellaneous features, such as file system access.
The software is provided under the GPL-2.0 license.
This software has hardware dependencies. The software has been tested using:
- STMicroelectronics b2020-h416 (orly-2) hardware (32-bits)
- Some initial testing has been done using Foundation FVP, which can be downloaded free of charge.
Get and build the software
Get the compiler
We will strive to use the latest available compiler from Linaro. Start by downloading and unpacking the compiler. Then export the PATH to the bin folder.
$ cd $HOME $ mkdir toolchains $ cd toolchains $ wget http://releases.linaro.org/14.05/components/toolchain/binaries/gcc-linaro-arm-linux-gnueabihf-4.9-2014.05_linux.tar.xz $ tar xvf gcc-linaro-arm-linux-gnueabihf-4.9-2014.05_linux.tar.xz $ export PATH=$HOME/toolchains/gcc-linaro-arm-linux-gnueabihf-4.9-2014.05_linux/bin:$PATH
$ cd $HOME $ mkdir devel $ cd devel $ tar xf linux-3.10.32.tar.xz $ mv linux-3.10.32 linux
Download the source code
$ cd $HOME $ cd devel $ git clone https://github.com/OP-TEE/optee_linuxdriver.git
$ cd $HOME/devel/linux $ make -j3 ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- mrproper $ make -j3 ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- defconfig $ make -j3 ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- all $ make -j3 ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- M=$HOME/devel/optee_linuxdriver modules
To be able to see the full command when building you could build using following flag:
$ make V=1
In this project we are trying to adhere to the same coding convention as used in the Linux kernel (see CodingStyle). We achieve this by running checkpatch from Linux kernel. However there are a few exceptions that we had to make since the code also follows GlobalPlatform standards. The exceptions are as follows:
- CamelCase for GlobalPlatform types are allowed.
- And we also exclude checking third party code that we might use in this project, such as LibTomCrypt, MPA, newlib (not in this particular git, but those are also part of the complete TEE solution). The reason for excluding and not fixing third party code is because we would probably deviate too much from upstream and therefore it would be hard to rebase against those projects later on (and we don't expect that it is easy to convince other software projects to change coding style).
Since checkpatch is licensed under the terms of GNU GPL License Version 2, we
cannot include this script directly into this project. Therefore we have
written the Makefile so you need to explicitly point to the script by exporting
an environment variable, namely CHECKPATCH. So, suppose that the source code for
the Linux kernel is at
$HOME/devel/linux, then you have to export like follows:
$ export CHECKPATCH=$HOME/devel/linux/scripts/checkpatch.pl
thereafter it should be possible to use one of the different checkpatch targets in the Makefile. There are targets for checking all files, checking against latest commit, against a certain base-commit etc. For the details, read the Makefile.