Merge pull request #215 from fischer-martin/bachelor_thesis_martin_fi…

…scher

add Martin Fischer's bachelor thesis

theses/README.md

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 # Bachelor Theses on Selfie
 
 
+## RISC-V S-Mode-Hosted Bare-Metal Selfie by Martin Fischer, University of Salzburg, Austria, 2020 ([PDF](https://github.com/cksystemsteaching/selfie/releases/download/bachelor_thesis_fischer/bachelor_thesis_fischer.pdf), [Release](https://github.com/cksystemsteaching/selfie/releases/tag/bachelor_thesis_fischer))
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+Modern operating systems like Linux run on a great variety of different machine architectures and have complicated mechanisms for process and resource management. Since this makes understanding their internals a tedious task, we present a simple preemptive multitasking kernel that targets a 64-bit RISC-V platform and which is tailored to run binaries compiled by selfie through the implementation of its Application Binary Interface. It runs in supervisor-mode, executes spatially isolated processes in user-mode, and communicates through the Supervisor Binary Interface with OpenSBI, a hardware abstraction layer, running in machine-mode; all while sharing core parts of its code base with a library operating system that is described in another bachelor thesis. The main difficulties that arise through the use of memory virtualization are discussed and solutions for them are presented. The kernel is able to execute on top of real RISC-V hardware in the form of a SiFive HiFive Unleashed.
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 ## Conservative Garbage Collection in Kernel and Mutator Space by Gregor Bachinger, University of Salzburg, Austria, 2020 ([PDF](https://github.com/cksystemsteaching/selfie/releases/download/bachelor_thesis_bachinger/bachelor_thesis_bachinger.pdf), [Release](https://github.com/cksystemsteaching/selfie/releases/tag/bachelor_thesis_bachinger))
 
 Compiling C or any similar language into binaries only provides support for explicit, manual memory management. To combat these issues, garbage collectors have been employed which handle memory management automatically. Since garbage collectors are specialized and use a lot of assumptions about their target environments, different algorithms are usually used for collectors in and outside of the mutator's address space. We have designed and implemented a conservative garbage collector that can run either in kernel or mutator space, or even in both at the same time. Running our collector in kernel and mutator space at the same time shows, that the collector is able to collect its own garbage. Furthermore, our experiments show the runtime/space tradeoff between collector invoke frequency and running it on machine and application level.