In-depth Analysis of x86's System Management Mode

Background

Besides Real and Protected Mode, modern x86 processors provide another mode of operation: the System Management Mode (SMM). The BIOS may install interrupt handlers (System Management Interrupts, SMI) that are executed in this mode what makes them uninterruptible and out of control by the operating system. There is no official method for accessing the memory where these routines are stored nor to deactivate their execution. If Virtual Machine Monitors can be called Ring -1, the System Management Mode is Ring -2. But there are methods to hack into this protected environment.

The intended use of routines under this mode is e.g. power-management purposes or the handling of USB-keyboards to translate them to the PS/2 interface. For real-time applications of x86 based hardware, this is a major drawback as the uninterruptible nature of this mode introduces an uncontrollable source of latency. But it offers also a chance to execute time-critical tasks under its protection.

Assingment

• Measurement and Analysis of preinstalled System Management Interrupts (SMI)
• Identify sources that trigger SMI
• Find ways to deactivate preinstalled SMI and check consequences
• Install and Evaluate Real-Time tasks in System-Management Mode
• Devellopment of Inter-Task-Communication between Tasks in SMM and the Operating System
• Comparison with Real-Time Extensions to the Linux Kernel and Virtual Machines

We offer

• Comfortable working-environment, as well as a good equipped Computer infrastructure
• Personal and engaged supervision

Profil of requirements

• Intermediate diploma of Electro- and Informationstechnics or (technical) computer science
• Alternatively the according prerequisites for a Master's thesis
• Good programming skills in C/C++
• Understanding of operating system internals and system programming
• Linux experience recommended
• Competence to work autonomous and creative

Contact