Master Thesis - Past Projects - Abstract
Implementing Memory Protection in a Minimal OS
The car industry has created a series of standards called AutoSAR as a response
to the increasing number of processors in modern vehicles. Among these specifications is one for real-time operating systems (RTOS). This RTOS standard
includes requirements for memory protection. This thesis outlines the work involved
in introducing the memory protection outlined in this specification in
the OSEck operating system. The work consisted of updating the operating
system, implementing the AutoSAR OS API, and updating the suite of tools
used to build the finished system.
The AutoSAR specifications were found to be very thorough and well thought
out. The OS API was successfully implemented, and the data-structures needed
to permit its functionality. The existing software tools were updated to conform
with the new requirements from AutoSAR, and additional software was created
to ease the configuration process.
Memory protection was successfully implemented in the OSEck operating
system, including two implementations of the trap interface. The memory protection
functionality adds yet another layer of user-configuration to the operating
system. Also, additional overhead for system calls, context switches and
message passing is expected. A general evaluation of how OSEck application
performance is aff ected is beyond the scope of this thesis, but preliminary studies
of additional instruction counts on certain system calls have been performed.
Keywords: MMU, Autosar, OSEK, Memory Protection, Embedded Systems
Author(s): Per Fagrell and Richard Eklycke
Contact: Simin Nadjm-Tehrani
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