Made available in DSpace on 2015-04-22T22:00:44Z (GMT). No. of bitstreams: 1 Francisco.pdf: 2605316 bytes, checksum: ee1fad3d9d9e7780947fc166b5909203 (MD5) Previous issue date: 2011-03-24 / The energy consumption in the past years became a very important issue in embedded system projects. The high production and wide application of mobile devices have forced the emergence of various restrictions to this system, such as: weight, size and lifetime of batteries and multiple functionalities. Mobile devices works under limited power source that autonomy and lifetime are directly related to energy consumption of the running applications. These concerns have contributed significantly to include the energy consumption as metric for project quality in embedded systems. The main goal of this work is to propose metrics, estimative and compare the energy consumption of programs code written in ANSI-C language, based on execution time of embedded systems. In order to support the approach it was improved a tool in algorithm level known as PESTI in multiple scenarios. It was written a program in ANSI-C language and loaded in processor of the ARM 7 family s. Then, it was added into this program flags to signalize start and stop in order to measure execution time of each track in analysis. The estimative tool already modified to attribute multiple scenarios, for a program written in ANSI-C and translated into an annotated control flow graph, with tracks assignments of probabilities. This model is probabilistically simulated by using Monte Carlo methodology. The proposed approach was validate carrying out a series of experimental in order to show the viability of the improved tool of estimation and characterization, which together will make the estimates of energy consumption somewhat more feasible.  Validate the proposed approach added;  Compare the results between simulation time and the tool for characterization PESTI with the same hardware platform embedded (ARM7). The experimental were divided in three steps:  Simulation of the code in the tool PESTI in multiple scenarios;  Characterization of the query code;  Comparison of the characterization tool and PESTI. The experiments were conducted on:  AMD Turion (tm) II Dual Core Mobile Processor M500, 2.20GHz, 4Gb of RAM;  OS Linux Mint Distribution kernel 2.6.22 32-bit; 11  OS Windows 7 32-bit. / Consumo de energia nos últimos anos tornou-se um aspecto importante em projetos de sistemas embarcados. A produção e utilização em larga escala dos dispositivos móveis tem imposto várias restrições como: peso, tamanho, tempo de vida útil da bateria e funcionalidades complexas. Dispositivos móveis operam sob uma fonte de energia limitada cuja autonomia e tempo de vida útil estão diretamente relacionados ao consumo de energia das aplicações. Estas questões contribuíram para incluir o consumo de energia como métrica de qualidade no projeto de sistemas embarcados. Este trabalho tem como objetivo propor uma abordagem de medição, estimação e comparação do consumo de energia de código de programas escritos em linguagem ANSI-C, baseados em ensaios de códigos previamente escolhidos com características de consumo de energia e no tempo de execução. Para dar suporte à abordagem, uma ferramenta de estimação chamada PESTI foi estendida para atender múltiplos cenários probabilísticos. Programas escritos em linguagem ANSI-C são embarcados no processador LPC2148 da família ARM 7. Nesse programa são inseridos flags de sinalização para start e stop, para delimitar o tempo de execução e medirmos o consumo de energia do código. Um hardware chamado de caracterizador de consumo de energia auxiliará na medição em tempo real de execução do código. A ferramenta de estimação chamada PESTI com características probabilísticas e atribuições para múltiplos cenários probabilísticos é usada para estimar o consumo de energia do programa escrito em ANSI-C. Validamos a abordagem proposta, executando um conjunto de experimentos mostrando a viabilidade da extensão da ferramenta de estimação e o caracterizador que, em conjunto, viabilizarão as estimativas de consumo de energia no processador alvo. As atividades realizadas para a execução dos experimentos foram:  Validar a abordagem proposta;  Comparar os resultados medidos e estimados entre a ferramenta PESTI com o caracterizador para a mesma plataforma de hardware embarcada (ARM7). Os experimentos foram divididos em três passos:  Estimação dos códigos na ferramenta PESTI em simples e múltiplos cenários;  Caracterização do código em questão;  Comparação da caracterização e ferramenta PESTI. 9 Onde os resultados obtidos mostram uma diferença entre os valores estimados e simulados e os resultados medidos. Os experimentos foram conduzidos sobre:  AMD Turion(tm) II Dual Core Mobile M500, 2.20GHz, 4GB de RAM;  SO Linux Distribuição Mint kernel 2.6.22;  SO de 32 bits Windows 7.

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Le but de cette thèse est d'apporter de nouvelles possibilités au domaine de la programmation Web, dont les technologies répandues ne capturent pas toutes les problématiques engendrées par les interactions dans une application. Notre solution est un langage, Pendulum, inspiré de la programmation synchrone réactive en Esterel et se présentant comme une extension à OCaml. Il permet de gagner en sûreté et en expressivité en particulier dans la gestion d'interaction multiples. Dans une première partie, nous présentons notre perception de la programmation Web d'aujourd'hui en partant du standard pour aller vers les technologies plus modernes qui tentent de subvenir aux besoins des programmes par d'autres approches, notamment la programmation multitier et les modèles de concurrence en flot de données. Dans une seconde partie, nous introduisons le langage Pendulum et ses constructions, ce qu'il propose comme interopérabilité avec le client Web le différenciant d'autres langages synchrones, et l'interface de programmation qui le connecte avec le langage hôte. Dans les parties trois et quatre, nous présentons la méthode de compilation utilisée, GRC, pour GraphCode, qui produit un graphe de flot de contrôle à partir du programme synchrone source. On revient sur la structure du GRC, les règles permettant de le construire, ainsi que notre méthode d'ordonnancement statique. Nous décrivons ensuite la génération de l'environnement d'exécution d'un programme synchrone dans le programme hôte. Dans une cinquième partie, nous montrons l'intérêt de la programmation synchrone dans le client et en quoi son modèle d'exécution s'adapte naturellement à celui du navigateur Web. Nous montrons qu'il est possible de profiter de cet avantage pour réagir aux évènements plus efficacement sans efforts d'optimisation. Avant de conclure, nous présentons de multiples exemples implémentés en Pendulum pour mettre en avant les qualités d'expressivité et de sûreté de la programmation synchrone sur différentes problématiques impliquant du multimédia et des interactions. / The goal of this thesis is to bring new capabilities to Web programming, whose languages, frameworks don't handle all the problematics raised by interactions in a Web application. Our solution is a programming language, Pendulum, taking its roots in synchronous reactive model à la Esterel. It brings safety and expressiveness, especially when handling multiple interactions. In the first chapter, we give our point of view on what is Web programming today, from the standard to the newest frameworks trying to fill programers needs by other approaches, like multitier programming or dataflow programming. In the second chapter, we introduce Pendulum and its instructions, its interface with the host language, and what it brings to both synchronous and Web programming. In the third and fourth chapter, we present the compilation method, GRC a.k.a GraphCode, that produces a control flow graph from the source code. In the first part, we insist mainly on GRC structure, the rules describing its creation and our technic to linearize parallel branches. Then, we describe the how to initialize synchronous execution environment in OCaml. In the fifth chapter, we show why it is a benefit to use synchronous programming in client programming and how its execution model can natively match the Web browser execution model. We use those ideas to show how a synchronous program can be fast to handle events without optimisation attempt. Before we conclude, we detail several examples implemented with our language to show how expressive and safe synchronous programming can be on diverse programs, implying multimedia and interactions.

This thesis is interested in format of executable files EXE. It is focused on parts relevant for reverse engineering. It is interested in assembler, binary representation of instruction and disassembling. Follow I introduce converting from executables to control flow graph, basic structures (branches, cycles) detection.

Memory corruption attacks pose a significant threat to the security of embedded devices with limited resources that lack basic protection mechanisms. Control Flow Integrity (CFI) is a promising technique to mitigate these attacks by ensuring that the program’s control flow adheres to a predetermined set of rules. In this project, we propose a CFI solution tailored for embedded devices based on combining a type-based approach for indirect branches with a shadow stack approach to protect return addresses. Our solution targets the ARM Cortex-M33 architecture and is evaluated on various applications that are adequate for low-end devices, including embedded cryptographic primitives and a real-time operating system. Our solution provides a high level of security, allowing for a 99.99% reduction in attacks using the average reduction metric (AIR). However, we acknowledge that the performance overhead may be a concern for some use cases. The evaluation of our Control Flow Integrity (CFI) implementation shows that it incurs a performance overhead ranging between 7% and 81%, with a relatively small size overhead of around 3%. Therefore, we propose that the use of adequate architectural models could help reduce the performance overhead while still maintaining good security guarantees. Our study highlights the trade-off between security and performance in CFI implementations and provides insights into potential areas for improvement. / Minneskorruptionsattacker utgör ett betydande hot mot säkerheten för inbyggda enheter med begränsade resurser som saknar grundläggande skyddsmekanismer. Kontrollflödesintegritet (CFI) är en lovande teknik för att mildra dessa attacker genom att säkerställa att programkontrollen följer en förutbestämd uppsättning regler. I detta projekt föreslår vi en CFI-lösning anpassad för inbyggda enheter som bygger på en kombination av en typbaserad metod för indirekta grenar med en skuggstackmetod för att skydda returadresser. Vår lösning riktar sig mot ARM Cortex-M33-arkitekturen och utvärderas på olika applikationer som är lämpliga för lågpresterande enheter, inklusive inbyggda kryptografiska grundläggande funktioner och ett realtidsoperativsystem. Vår lösning erbjuder en hög säkerhetsnivå och möjliggör en minskning av attacker med 99,99% enligt genomsnittsmätningsmetoden (AIR). Vi erkänner dock att prestandaöverhuvud kan vara en oro i vissa användningsfall. Utvärderingen av vår CFI-implementering visar att den medför en prestandaöverhuvud som varierar mellan 7% och 81%, med en relativt liten storleksöverhuvud på cirka 3%. Därför föreslår vi att användningen av lämpliga arkitekturmodeller kan bidra till att minska prestandaöverhuvudet samtidigt som goda säkerhetsgarantier bibehålls. Vår studie belyser avvägningen mellan säkerhet och prestanda i CFI-implementeringar och ger insikter om potentiella områden för förbättring.

Les systèmes embarqués sont de plus en plus utilisés dans des domaines divers tels que le transport, l’automatisation industrielle, les télécommunications ou la santé pour exécuter des applications critiques et manipuler des données sensibles. Ces systèmes impliquent souvent des intérêts financiers et industriels, mais aussi des vies humaines ce qui impose des contraintes fortes de sûreté. Par conséquent, un élément clé réside dans la capacité de tels systèmes à répondre correctement quand des erreurs se produisent durant l’exécution et ainsi empêcher des comportements induits inacceptables. Les erreurs peuvent être d’origines naturelles telles que des impacts de particules, du bruit interne (problème d’intégrité), etc. ou provenir d’attaques malveillantes. Les architectures de systèmes embarqués comprennent généralement un ou plusieurs processeurs, des mémoires, des contrôleurs d’entrées/sorties ainsi que des accélérateurs matériels utilisés pour améliorer l’efficacité énergétique et les performances. Avec l’évolution des applications, le cycle de conception d’accélérateurs matériels devient de plus en plus complexe. Cette complexité est due en partie aux spécifications des accélérateurs matériels qui reposent traditionnellement sur l’écriture manuelle de fichiers en langage de description matérielle (HDL).Cependant, la synthèse de haut niveau (HLS) qui favorise la génération automatique ou semi-automatique d’accélérateurs matériels à partir de spécifications logicielles, comme du code C, permet de réduire cette complexité.Le travail proposé dans ce manuscrit cible l’intégration d’un support de vérification dans les outils de HLS pour générer des moniteurs sur puce au cours de la synthèse de haut niveau des accélérateurs matériels. Trois contributions distinctes ont été proposées. La première contribution consiste à contrôler les erreurs de comportement temporel des entrées/sorties (impactant la synchronisation avec le reste du système) ainsi que les erreurs du flot de contrôle (sauts illégaux ou problèmes de boucles infinies). La synthèse des moniteurs est automatique sans qu’aucune modification de la spécification utilisée en entrée de la HLS ne soit nécessaire. La deuxième contribution vise la synthèse des propriétés de haut niveau (ANSI-C asserts) qui ont été ajoutées dans la spécification logicielle de l’accélérateur matériel. Des options de synthèse ont été proposées pour arbitrer le compromis entre le surcout matériel, la dégradation de la performance et le niveau de protection. La troisième contribution améliore la détection des corruptions des données qui peuvent modifier les valeurs stockées, et/ou modifier les transferts de données, sans violer les assertions (propriétés) ni provoquer de sauts illégaux. Ces erreurs sont détectées en dupliquant un sous-ensemble des données du programme, limité aux variables les plus critiques. En outre, les propriétés sur l’évolution des variables d’induction des boucles ont été automatiquement extraites de la description algorithmique de l’accélérateur matériel. Il faut noter que l’ensemble des approches proposées dans ce manuscrit, ne s’intéresse qu’à la détection d’erreurs lors de l’exécution. La contreréaction c.à.d. la manière dont le moniteur réagit si une erreur est détectée n’est pas abordée dans ce document. / Embedded systems are increasingly used in various fields like transportation, industrial automation, telecommunication or healthcare to execute critical applications and manipulate sensitive data. These systems often involve financial and industrial interests but also human lives which imposes strong safety constraints.Hence, a key issue lies in the ability of such systems to respond safely when errors occur at runtime and prevent unacceptable behaviors. Errors can be due to natural causes such as particle hits as well as internal noise, integrity problems, but also due to malicious attacks. Embedded system architecture typically includes processor (s), memories, Input / Output interface, bus controller and hardware accelerators that are used to improve both energy efficiency and performance. With the evolution of applications, the design cycle of hardware accelerators becomes more and more complex. This complexity is partly due to the specification of hardware accelerators traditionally based on handwritten Hardware Description Language (HDL) files. However, High-Level Synthesis (HLS) that promotes automatic or semi-automatic generation of hardware accelerators according to software specification, like C code, allows reducing this complexity.The work proposed in this document targets the integration of verification support in HLS tools to generate On-Chip Monitors (OCMs) during the high-level synthesis of hardware accelerators (HWaccs). Three distinct contributions are proposed. The first one consists in checking the Input / Output timing behavior errors (synchronization with the whole system) as well as the control flow errors (illegal jumps or infinite loops). On-Chip Monitors are automatically synthesized and require no modification in their high-level specification. The second contribution targets the synthesis of high-level properties (ANSI-C asserts) that are added into the software specification of HWacc. Synthesis options are proposed to trade-off area overhead, performance impact and protection level. The third contribution improves the detection of data corruptions that can alter the stored values or/and modify the data transfers without causing assertions violations or producing illegal jumps. Those errors are detected by duplicating a subset of program’s data limited to the most critical variables. In addition, the properties over the evolution of loops induction variables are automatically extracted from the algorithmic description of HWacc. It should be noticed that all the proposed approaches, in this document, allow only detecting errors at runtime. The counter reaction i.e. the way how the HWacc reacts if an error is detected is out of scope of this work.

<p>Real-time systems do not only require that the logical operations are correct. Equally important is that the specified time constraints always are complied. This has successfully been studied before for mono-processor systems. However, as the hardware in the systems gets more complex, the previous approaches become invalidated. For example, multi-processor systems-on-chip (MPSoC) get more and more common every day, and together with a shared memory, the bus access time is unpredictable in nature. This has recently been resolved, but a safe and not too pessimistic cache analysis approach for MPSoC has not been investigated before. This thesis has resulted in designed and implemented algorithms for cache analysis on real-time MPSoC with a shared communication infrastructure. An additional advantage is that the algorithms include improvements compared to previous approaches for mono-processor systems. The verification of these algorithms has been performed with the help of data flow analysis theory. Furthermore, it is not known how different types of cache miss characteristic of a task influence the worst case execution time on MPSoC. Therefore, a program that generates randomized tasks, according to different parameters, has been constructed. The parameters can, for example, influence the complexity of the control flow graph and average distance between the cache misses.</p>

Real-time systems do not only require that the logical operations are correct. Equally important is that the specified time constraints always are complied. This has successfully been studied before for mono-processor systems. However, as the hardware in the systems gets more complex, the previous approaches become invalidated. For example, multi-processor systems-on-chip (MPSoC) get more and more common every day, and together with a shared memory, the bus access time is unpredictable in nature. This has recently been resolved, but a safe and not too pessimistic cache analysis approach for MPSoC has not been investigated before. This thesis has resulted in designed and implemented algorithms for cache analysis on real-time MPSoC with a shared communication infrastructure. An additional advantage is that the algorithms include improvements compared to previous approaches for mono-processor systems. The verification of these algorithms has been performed with the help of data flow analysis theory. Furthermore, it is not known how different types of cache miss characteristic of a task influence the worst case execution time on MPSoC. Therefore, a program that generates randomized tasks, according to different parameters, has been constructed. The parameters can, for example, influence the complexity of the control flow graph and average distance between the cache misses.

The aim of the masters thesis is to design and implement a tool for automatic generation of paths in source code. Firstly was acquired a study of model based testing and possible design for the desired automatic generator based on coverage criteria defined on CFG model. The main point of the master theis is the tool design and description of its implementation. The tool supports many coverage criteria, which allows the user of such tool to focus on specific artefact of the system under test. Moreover, this tool is tuned to allow aditional requirements on the size of generated test suite, reflecting real world practical usage. The generator was implemented in C++ language and web interface for it in Python language, which at the same time is used to integrated the tool into Testos platform.