Research On The Key Technology In Separation Kernel For Avionics

The traditional approach of the’Fail-first, Patch-later’can not meet the requirements of avionics system for the security of airborne software. The system based on monolithic kernel can’t ensure the security of itself, because of the complex function and the large structure of the kernel. The Multiple Independent Levels of Security (MILS) architecture implement with separation kernel, solves security problem from prevention. Thus, as the basis of the MILS architecture, the separation kernel has gradually become a hot focus of domestic researches. This paper will focus on the key technology of the separation kernel.Based on the characteristic of the integrated modular avionics, this paper firstly analyzes the environment of the aviation and the military affairs, communication condition, efficiency, application requirements and its limitations, etc., the model of the multiple independent security distributed system is studied. The TRAP system calling mechanism and the interface of kernel are designed. The TRAP system calling mechanism can ensure the system call could be preempted. The interface of kernel will meet the functional requirements of separation kernel and provide a foundation for the development of upper layer. Then, dynamic partitioning scheduling algorithm is designed and dynamic partitioning scheduling is implemented by this algorithm. An improved model of shared memory based on the separation kernel is proposed, therefore, guaranteed the reliability and efficiency of message passing.Compared with the traditional system calling mechanism, the TRAP system calling mechanism of the separation kernel designed in this paper can reduce the time of disable interrupts effectively and response the hardware interrupt promptly. Experimental results show that the proposed dynamic scheduling algorithm have improved the CPU utilization and solved the problem of low CPU utilization by using static scheduling when the system is in free mode.The implementation of the functionality about the periods processing of the separation kernel will be researched in the future, thus improved functionality and interface of the separation kernel.