A Study Of Exokernel Operating System On Multi-core Architecture

Operating systems abstract, multiplex and protect the physical resources of multicore processor computing platforms, and provide resource access interfaces for applications. The abstract interfaces of traditional operating systems are over generalized and high-level resource abstract hides hardware information, which limit the performance, functionality and flexibility of applications. In this thesis, Exokernel architecture is utilized to provide more flexible and efficient interfaces. Exokernel separates resource management from protection, which makes the kernel protects resources and non-privileged applications manage resources. In Exokernel, applications are more flexible and efficient to control resources. The work presented in this thesis is to implement a prototype of Exokernel operating system in single core platform, and then expand it to multicore platforms.The functional components of the single-core prototype include system initialization, memory management, process management and inter-process communication. The components are implemented and validated by step-by-step iteration. Page self-mapping is utilized to safely access page directory entries and page table entries in order to create sub-process in user space. The interrupt handling for page fault in user space is more flexible and secure than the traditional. The more flexible inter-process communication is enabled by message mechanism in user space.To expand the single-core prototype to multicore, this thesis implements the initialization of multicore, including the hard coded page directory and page table to enable paging in each core, and adding process status to avoid one process running in several cores, adopting Big Kernel Lock (BKL) to implement exclusive running of kernel codes in several cores. Finally, there is validation for the functional correctness of Exokernel operating system prototype in multicore platforms.