This repository contains a proof of concept code for the paper uSFI: Ultra-Lightweight Software Fault Isolation for IoT-Class Devices which was presented at DATE18.

The repo contains the following directories:

Drivers - Target specific drivers. Only drivers required to run the example applications are included here.

Led_blink - Source files for the example application.

LLVM - Contains code for the task-attribute LLVM pass.

Scripts - Python scripts used for compilation.

uSFI - source files for uSFI application interface and a target specific system call handler. The system call handler targets stm32f4xx devices.

The example application is a simple hello world application that blinks an LED and at the same time prints a message over the UART port. The application targets the STM32 NUCLEO-F446RE development board. The example application has two modules in addition to a main module - gpio module and uart module. The gpio module has access to PORTA peripheral where the LED is connected, while the uart module has access to the USART2 peripheral.

To compile the application, use the bash script in the Led_blink folder. The script assumes gcc ARM cross-compiler and LLVM are installed. Before compiling, set the LLVM_PASS_PATH variable in the scripts in the Drivers directory to the task-attribute pass library directory path.

cd Led_blink ./usfi.sh

To run the application you can simply copy the generated Led_blink.bin file to the development board.