1# OP-TEE Trusted OS 2The optee_os git, containing the source code for the TEE in Linux using 3the ARM(R) Trustzone(R) technology. This component meets the Global 4Platform TEE System Architecture specification. It also provides the 5TEE Internal API v1.0 as defined by the Global Platform TEE Standard 6for the development of trusted apllications. 7It is distributed mostly under the BSD 2-clause open-source license. 8It includes few external files under BSD 3-clause license or other free 9software licenses. For a general overview of OP-TEE, please see the 10[Notice.md](Notice.md) file. 11 12In this git, the binary to build is tee.elf. 13The Trusted OS is accessible from the Rich OS (Linux) through the Global 14Platform TEE Client API and performs secure execution of applications 15inside the TEE. 16 17## License 18The software is provided under the 19[BSD 2-Clause](http://opensource.org/licenses/BSD-2-Clause) license. 20[BSD 3-Clause](http://opensource.org/licenses/BSD-3-Clause) license. 21 22## Platforms supported 23This software has hardware dependencies. 24The software has been tested using: 25 26- STMicroelectronics b2020-h416 (orly-2) hardware (32-bits) 27- Some initial testing has been done using 28[Foundation FVP](http://www.arm.com/fvp), which can be downloaded free of 29charge. 30 31## Get and build the software 32### Get the compiler 33We will strive to use the latest available compiler from Linaro. Start by 34downloading and unpacking the compiler. Then export the PATH to the bin folder. 35 36 $ cd $HOME 37 $ mkdir toolchains 38 $ cd toolchains 39 $ wget http://releases.linaro.org/14.05/components/toolchain/binaries/gcc-linaro-arm-linux-gnueabihf-4.9-2014.05_linux.tar.xz 40 $ tar xvf gcc-linaro-arm-linux-gnueabihf-4.9-2014.05_linux.tar.xz 41 $ export PATH=$HOME/toolchains/gcc-linaro-arm-linux-gnueabihf-4.9-2014.05_linux/bin:$PATH 42 43### Download the source code 44 $ cd $HOME 45 $ mkdir devel 46 $ cd devel 47 $ git clone https://github.com/OP-TEE/optee_os.git 48 49### Build 50 $ cd $HOME/devel/optee_os 51 $ CROSS_COMPILE=arm-linux-gnueabihf- make 52 53#### Compiler flags 54To be able to see the full command when building you could build using following 55flag: 56 57`$ make V=1` 58 59## Coding standards 60In this project we are trying to adhere to the same coding convention as used in 61the Linux kernel (see 62[CodingStyle](https://www.kernel.org/doc/Documentation/CodingStyle)). We achieve this by running 63[checkpatch](http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/scripts/checkpatch.pl) from Linux kernel. 64However there are a few exceptions that we had to make since the code also 65follows GlobalPlatform standards. The exceptions are as follows: 66 67- CamelCase for GlobalPlatform types are allowed. 68- And we also exclude checking third party code that we might use in this 69 project, such as LibTomCrypt, MPA, newlib (not in this particular git, but 70 those are also part of the complete TEE solution). The reason for excluding 71 and not fixing third party code is because we would probably deviate too much 72 from upstream and therefore it would be hard to rebase against those projects 73 later on (and we don't expect that it is easy to convince other software 74 projects to change coding style). 75 76### checkpatch 77Since checkpatch is licensed under the terms of GNU GPL License Version 2, we 78cannot include this script directly into this project. Therefore we have 79written the Makefile so you need to explicitly point to the script by exporting 80an environment variable, namely CHECKPATCH. So, suppose that the source code for 81the Linux kernel is at `$HOME/devel/linux`, then you have to export like follows: 82 83 $ export CHECKPATCH=$HOME/devel/linux/scripts/checkpatch.pl 84thereafter it should be possible to use one of the different checkpatch targets 85in the [Makefile](Makefile). There are targets for checking all files, checking 86against latest commit, against a certain base-commit etc. For the details, read 87the [Makefile](Makefile). 88