OP-TEE Linux Driver

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.

License

The software is provided under the GPL-2.0 license.

Platforms supported

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

Get the Linux kernel (from www.kernel.org)

$ 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

Build

$ 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

Compiler flags

To be able to see the full command when building you could build using following flag:

$ make V=1

Coding standards

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).

checkpatch

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.