Operating System Verification—An Overview
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UG1046 Ultrafast Embedded Design Methodology Guide
UltraFast Embedded Design Methodology Guide UG1046 (v2.3) April 20, 2018 Revision History The following table shows the revision history for this document. Date Version Revision 04/20/2018 2.3 • Added a note in the Overview section of Chapter 5. • Replaced BFM terminology with VIP across the user guide. 07/27/2017 2.2 • Vivado IDE updates and minor editorial changes. 04/22/2015 2.1 • Added Embedded Design Methodology Checklist. • Added Accessing Documentation and Training. 03/26/2015 2.0 • Added SDSoC Environment. • Added Related Design Hubs. 10/20/2014 1.1 • Removed outdated information. •In System Level Considerations, added information to the following sections: ° Performance ° Clocking and Reset 10/08/2014 1.0 Initial Release of document. UltraFast Embedded Design Methodology Guide Send Feedback 2 UG1046 (v2.3) April 20, 2018 www.xilinx.com Table of Contents Chapter 1: Introduction Embedded Design Methodology Checklist. 9 Accessing Documentation and Training . 10 Chapter 2: System Level Considerations Performance. 13 Power Consumption . 18 Clocking and Reset. 36 Interrupts . 41 Embedded Device Security . 45 Profiling and Partitioning . 51 Chapter 3: Hardware Design Considerations Configuration and Boot Devices . 63 Memory Interfaces . 69 Peripherals . 76 Designing IP Blocks . 94 Hardware Performance Considerations . 102 Dataflow . 108 PL Clocking Methodology . 112 ACP and Cache Coherency. 116 PL High-Performance Port Access. 120 System Management Hardware Assistance. 124 Managing Hardware Reconfiguration . 127 GPs and Direct PL Access from APU . 133 Chapter 4: Software Design Considerations Processor Configuration . 137 OS and RTOS Choices . 142 Libraries and Middleware . 152 Boot Loaders . 156 Software Development Tools . 162 UltraFast Embedded Design Methodology GuideSend Feedback 3 UG1046 (v2.3) April 20, 2018 www.xilinx.com Chapter 5: Hardware Design Flow Overview . -
The OKL4 Microvisor: Convergence Point of Microkernels and Hypervisors
The OKL4 Microvisor: Convergence Point of Microkernels and Hypervisors Gernot Heiser, Ben Leslie Open Kernel Labs and NICTA and UNSW Sydney, Australia ok-labs.com ©2010 Open Kernel Labs and NICTA. All rights reserved. Microkernels vs Hypervisors > Hypervisors = “microkernels done right?” [Hand et al, HotOS ‘05] • Talks about “liability inversion”, “IPC irrelevance” … > What’s the difference anyway? ok-labs.com ©2010 Open Kernel Labs and NICTA. All rights reserved. 2 What are Hypervisors? > Hypervisor = “virtual machine monitor” • Designed to multiplex multiple virtual machines on single physical machine VM1 VM2 Apps Apps AppsApps AppsApps OS OS Hypervisor > Invented in ‘60s to time-share with single-user OSes > Re-discovered in ‘00s to work around broken OS resource management ok-labs.com ©2010 Open Kernel Labs and NICTA. All rights reserved. 3 What are Microkernels? > Designed to minimise kernel code • Remove policy, services, retain mechanisms • Run OS services in user-mode • Software-engineering and dependability reasons • L4: ≈ 10 kLOC, Xen ≈ 100 kLOC, Linux: ≈ 10,000 kLOC ServersServers ServersServers Apps Servers Device AppsApps Drivers Microkernel > IPC performance critical (highly optimised) • Achieved by API simplicity, cache-friendly implementation > Invented 1970 [Brinch Hansen], popularised late ‘80s (Mach, Chorus) ok-labs.com ©2010 Open Kernel Labs and NICTA. All rights reserved. 4 What’s the Difference? > Both contain all code executing at highest privilege level • Although hypervisor may contain user-mode code as well > Both need to abstract hardware resources • Hypervisor: abstraction closely models hardware • Microkernel: abstraction designed to support wide range of systems > What must be abstracted? • Memory • CPU • I/O • Communication ok-labs.com ©2010 Open Kernel Labs and NICTA. -
Access Control and Operating System
Outline (may not finish in one lecture) Access Control and Operating Access Control Concepts Secure OS System Security • Matrix, ACL, Capabilities • Methods for resisting • Multi-level security (MLS) stronger attacks OS Mechanisms Assurance • Multics • Orange Book, TCSEC John Mitchell – Ring structure • Common Criteria • Amoeba • Windows 2000 – Distributed, capabilities certification • Unix Some Limitations – File system, Setuid • Information flow • Windows • Covert channels – File system, Tokens, EFS • SE Linux – Role-based, Domain type enforcement Access control Access control matrix [Lampson] Common Assumption Objects • System knows who the user is File 1 File 2 File 3 … File n – User has entered a name and password, or other info • Access requests pass through gatekeeper User 1 read write - - read – OS must be designed monitor cannot be bypassed User 2 write write write - - Reference Subjects monitor User 3 - - - read read User process ? Resource … User m read write read write read Decide whether user can apply operation to resource Two implementation concepts Capabilities Access control list (ACL) File 1 File 2 … Operating system concept • “… of the future and always will be …” • Store column of matrix User 1 read write - Examples with the resource User 2 write write - • Dennis and van Horn, MIT PDP-1 Timesharing Capability User 3 - - read • Hydra, StarOS, Intel iAPX 432, Eros, … • User holds a “ticket” for … • Amoeba: distributed, unforgeable tickets each resource User m read write write • Two variations References – store -
Research Purpose Operating Systems – a Wide Survey
GESJ: Computer Science and Telecommunications 2010|No.3(26) ISSN 1512-1232 RESEARCH PURPOSE OPERATING SYSTEMS – A WIDE SURVEY Pinaki Chakraborty School of Computer and Systems Sciences, Jawaharlal Nehru University, New Delhi – 110067, India. E-mail: [email protected] Abstract Operating systems constitute a class of vital software. A plethora of operating systems, of different types and developed by different manufacturers over the years, are available now. This paper concentrates on research purpose operating systems because many of them have high technological significance and they have been vividly documented in the research literature. Thirty-four academic and research purpose operating systems have been briefly reviewed in this paper. It was observed that the microkernel based architecture is being used widely to design research purpose operating systems. It was also noticed that object oriented operating systems are emerging as a promising option. Hence, the paper concludes by suggesting a study of the scope of microkernel based object oriented operating systems. Keywords: Operating system, research purpose operating system, object oriented operating system, microkernel 1. Introduction An operating system is a software that manages all the resources of a computer, both hardware and software, and provides an environment in which a user can execute programs in a convenient and efficient manner [1]. However, the principles and concepts used in the operating systems were not standardized in a day. In fact, operating systems have been evolving through the years [2]. There were no operating systems in the early computers. In those systems, every program required full hardware specification to execute correctly and perform each trivial task, and its own drivers for peripheral devices like card readers and line printers. -
Sel4: Formal Verification of an Operating-System Kernel
seL4: Formal Verification of an Operating-System Kernel Gerwin Klein1;2, June Andronick1;2, Kevin Elphinstone1;2, Gernot Heiser1;2;3 1 1 1;2 1;2 David Cock , Philip Derrin ∗, Dhammika Elkaduwe ,z Kai Engelhardt 1;2 1;4 1 1;2 1;2 Rafal Kolanski , Michael Norrish , Thomas Sewell , Harvey Tuch y, Simon Winwood 1 NICTA, 2 UNSW, 3 Open Kernel Labs, 4 ANU [email protected] ABSTRACT We report on the formal, machine-checked verification of the seL4 microkernel from an abstract specification down to its C implementation. We assume correctness of compiler, assembly code, hardware, and boot code. seL4 is a third-generation microkernel of L4 provenance, comprising 8,700 lines of C and 600 lines of assembler. Its performance is comparable to other high-performance L4 kernels. We prove that the implementation always strictly follows our high-level abstract specification of kernel behaviour. This encompasses traditional design and implementation safety properties such as that the kernel will never crash, and it will never perform an unsafe operation. It also implies much more: we can predict precisely how the kernel will behave in every possible situation. 1. INTRODUCTION Almost every paper on formal verification starts with the observation that software complexity is increasing, that this Figure 1: Call graph of the seL4 microkernel. Ver- leads to errors, and that this is a problem for mission and tices represent functions, and edges invocations. safety critical software. We agree, as do most. Here, we report on the full formal verification of a critical system from a high-level model down to very low-level C kernel, and every single bug can potentially cause arbitrary code. -
Mixed-Criticality Scheduling and Resource Sharing for High-Assurance Operating Systems
Mixed-Criticality Scheduling and Resource Sharing for High-Assurance Operating Systems Anna Lyons Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy School of Computer Science and Engineering University of New South Wales Sydney, Australia September 2018 Abstract Criticality of a software system refers to the severity of the impact of a failure. In a high-criticality system, failure risks significant loss of life or damage to the environ- ment. In a low-criticality system, failure may risk a downgrade in user-experience. As criticality of a software system increases, so too does the cost and time to develop that software: raising the criticality also raises the assurance level, with the highest levels requiring extensive, expensive, independent certification. For modern cyber-physical systems, including autonomous aircraft and other vehicles, the traditional approach of isolating systems of different criticality by using completely separate physical hardware, is no longer practical, being both restrictive and inefficient. The result is mixed-criticality systems, where software applications with different criticalities execute on the same hardware. Sufficient mechanisms are required to ascertain that software in mixed-criticality systems is sufficiently isolated, otherwise, all software on that hardware is promoted to the highest criticality level, driving up costs to impractical levels. For mixed-criticality systems to be viable, both spatial and temporal isolation are required. Current aviation standards allow for mixed-criticality systems where temporal and spatial resources are strictly and statically partitioned in time and space, allowing some improvement over fully isolated hardware. However, further improvements are not only possible, but required for future innovation in cyber-physical systems. -
Operating System Support for Run-Time Security with a Trusted Execution Environment
Operating System Support for Run-Time Security with a Trusted Execution Environment - Usage Control and Trusted Storage for Linux-based Systems - by Javier Gonz´alez Ph.D Thesis IT University of Copenhagen Advisor: Philippe Bonnet Submitted: January 31, 2015 Last Revision: May 30, 2015 ITU DS-nummer: D-2015-107 ISSN: 1602-3536 ISBN: 978-87-7949-302-5 1 Contents Preface8 1 Introduction 10 1.1 Context....................................... 10 1.2 Problem....................................... 12 1.3 Approach...................................... 14 1.4 Contribution.................................... 15 1.5 Thesis Structure.................................. 16 I State of the Art 18 2 Trusted Execution Environments 20 2.1 Smart Cards.................................... 21 2.1.1 Secure Element............................... 23 2.2 Trusted Platform Module (TPM)......................... 23 2.3 Intel Security Extensions.............................. 26 2.3.1 Intel TXT.................................. 26 2.3.2 Intel SGX.................................. 27 2.4 ARM TrustZone.................................. 29 2.5 Other Techniques.................................. 32 2.5.1 Hardware Replication........................... 32 2.5.2 Hardware Virtualization.......................... 33 2.5.3 Only Software............................... 33 2.6 Discussion...................................... 33 3 Run-Time Security 36 3.1 Access and Usage Control............................. 36 3.2 Data Protection................................... 39 3.3 Reference -
Partitioned System with Xtratum on Powerpc
Tesina de M´asteren Autom´aticae Inform´aticaIndustrial Partitioned System with XtratuM on PowerPC Author: Rui Zhou Advisor: Prof. Alfons Crespo i Lorente December 2009 Contents 1. Introduction1 1.1. MILS......................................2 1.2. ARINC 653..................................3 1.3. PikeOS.....................................6 1.4. ADEOS....................................7 2. Overview of XtratuM 11 2.1. Virtualization and Hypervisor........................ 11 2.2. XtratuM.................................... 12 3. Overview of PowerPC 16 3.1. POWER.................................... 16 3.2. PowerPC.................................... 17 3.3. PowerPC in Safety-critical.......................... 19 4. Main PowerPC Drivers to Virtualize 20 4.1. Processors................................... 20 4.2. Timer..................................... 21 4.3. Interrupt.................................... 23 4.4. Memory.................................... 24 5. Porting Implementation 25 5.1. Hypercall................................... 26 5.2. Timer..................................... 27 5.3. Interrupt.................................... 28 5.4. Memory.................................... 31 5.5. Partition.................................... 32 6. Benchmark 34 7. Conclusions and Future Work 38 Abstract Nowadays, the diversity of embedded applications has been developed into a new stage with the availability of various new high-performance processors and low cost on-chip memory. As the result of these new advances in hardware, there is a -
OKL4 Microkernel Reference Manual
OKL4 Microkernel Reference Manual API Version 0316 Document Number: OK 10000:2006 (revision 12) Software Version: 3.0 Date: September 11, 2008 Copyright 2006–2008 Open Kernel Labs, Inc. Copyright 2006 National ICT Australia Limited This publication is distributed by Open Kernel Labs Pty Ltd, Australia. THIS DOCUMENT IS PROVIDED “AS IS” WITHOUT ANY WARRANTIES, INCLUDING ANY WARRANTY OF MERCHANTABILITY, NON-INFIRNGEMENT, FITNESS FOR ANY PARTICULAR PURPOSE, OR ANY WARRANTY OTHERWISE ARISING OF ANY PROPOSAL, SPECIFICATION OR SAMPLE. Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage, the copyright notice, the title of the publication and its date appear, and notice is given that copyright is by permission of the authors. To copy otherwise, to republish, to post on servers, or to redistribute to lists requires prior specific permission and/or a fee. Authors: Open Kernel Labs Contact Details: Open Kernel Labs Pty Ltd Attention: Open Kernel Labs Suite 3, 540 Botany Road Alexandria, NSW 2015 Australia email: [email protected] web: http://www.ok-labs.com/ 3 Contents Preface 15 1 Introduction 17 1.1 Outline of This Manual 18 1.2 Definitions 18 1.3 Notation 19 1.4 Credits 20 PART A—GENERIC INTERFACE A-1 Overview 23 A-1.1 The OKL4 Programming Environment 23 A-1.2 OKL4 API Elements 24 A-1.3 Compatibility between OKL4 Versions 24 A-1.4 Variants of the OKL4 API 25 A-1.5 Microkernel Extensions and -
Scalability of Microkernel-Based Systems
Scalability of Microkernel-Based Systems Zur Erlangung des akademischen Grades eines DOKTORS DER INGENIERWISSENSCHAFTEN von der Fakultat¨ fur¨ Informatik der Universitat¨ Fridericiana zu Karlsruhe (TH) genehmigte DISSERTATION von Volkmar Uhlig aus Dresden Tag der mundlichen¨ Prufung:¨ 30.05.2005 Hauptreferent: Prof. Dr. rer. nat. Gerhard Goos Universitat¨ Fridericiana zu Karlsruhe (TH) Korreferent: Prof. Dr. sc. tech. (ETH) Gernot Heiser University of New South Wales, Sydney, Australia Karlsruhe: 15.06.2005 i Abstract Microkernel-based systems divide the operating system functionality into individ- ual and isolated components. The system components are subject to application- class protection and isolation. This structuring method has a number of benefits, such as fault isolation between system components, safe extensibility, co-existence of different policies, and isolation between mutually distrusting components. How- ever, such strict isolation limits the information flow between subsystems including information that is essential for performance and scalability in multiprocessor sys- tems. Semantically richer kernel abstractions scale at the cost of generality and mini- mality–two desired properties of a microkernel. I propose an architecture that al- lows for dynamic adjustment of scalability-relevant parameters in a general, flex- ible, and safe manner. I introduce isolation boundaries for microkernel resources and the system processors. The boundaries are controlled at user-level. Operating system components and applications can transform their semantic information into three basic parameters relevant for scalability: the involved processors (depending on their relation and interconnect), degree of concurrency, and groups of resources. I developed a set of mechanisms that allow a kernel to: 1. efficiently track processors on a per-resource basis with support for very large number of processors, 2. -
Introduction Course Outline Why Does This Fail? Lectures Tutorials
Course Outline • Prerequisites – COMP2011 Data Organisation • Stacks, queues, hash tables, lists, trees, heaps,…. Introduction – COMP2021 Digital Systems Structure • Assembly programming • Mapping of high-level procedural language to assembly COMP3231/9201/3891/9283 language – or the postgraduate equivalent (Extended) Operating Systems – You are expected to be competent Kevin Elphinstone programmers!!!! • We will be using the C programming language – The dominant language for OS implementation. – Need to understand pointers, pointer arithmetic, explicit 2 memory allocation. Why does this fail? Lectures • Common for all courses (3231/3891/9201/9283) void func(int *x, int *y) • Wednesday, 2-4pm { • Thursday, 5-6pm *x = 1; *y = 2; – All lectures are here (EE LG03) – The lecture notes will be available on the course web site } • Available prior to lectures, when possible. void main() – The lecture notes and textbook are NOT a substitute for { attending lectures. int *a, *b; func(a,b); } 3 4 Tutorials Assignments • Assignments form a substantial component of • Start in week 2 your assessment. • A tutorial participation mark will • They are challenging!!!! – Because operating systems are challenging contribute to your final assessment. • We will be using OS/161, – Participation means participation, NOT – an educational operating system attendance. – developed by the Systems Group At Harvard – Comp9201/3891/9283 students excluded – It contains roughly 20,000 lines of code and comments • You will only get participation marks in your enrolled tutorial. 5 6 1 Assignments Assignments • Assignments are in pairs • Don’t under estimate the time needed to do the – Info on how to pair up available soon assignments. • We usually offer advanced versions of the – ProfQuotes: [About the midterm] "We can't keep you working assignments on it all night, it's not OS.“ Ragde, CS341 – Available bonus marks are small compared to amount of • If you start a couple days before they are due, you will be late. -
Lltzvisor: a Lightweight Trustzone-Assisted Hypervisor for Low-End ARM Devices
Hugo Miguel Eira Araújo lLTZVisor: A Lightweight TrustZone-assisted Hypervisor for low-end ARM Devices Outubro de 2018 Hugo Miguel Eira Araújo lLTZVisor: A Lightweight TrustZone-assisted Hypervisor for low-end ARM devices Dissertação de Mestrado em Engenharia Eletrónica Industrial e Computadores Trabalho efetuado sob a orientação do Doutor Sandro Pinto Outubro de 2018 Declaração do Autor Nome: Hugo Miguel Eira Araújo Correio Eletrónico: [email protected] Cartão de Cidadão: 14887613 Titulo da dissertação: lLTZVisor: A Lightweight TrustZone-assisted Hyper- visor for low-end ARM Devices Ano de conclusão: 2018 Orientador: Doutor Sandro Pinto Designação do Mestrado: Ciclo de Estudos Integrados Conducentes ao Grau de Mestre em Engenharia Eletrónica Industrial e Computadores Área de Especialização: Sistemas Embebidos e Computadores Escola de Engenharia Departamento de Eletrónica Industrial De acordo com a legislação em vigor, não é permitida a reprodução de qualquer parte desta dissertação. Universidade do Minho, 29/10/2018 Assinatura: Hugo Miguel Eira Araújo v Acknowledgements The accomplishment of this master’s thesis involved great contributions from sev- eral people, whom I will be eternally grateful. Foremost, I would like to express my gratitude to my advisor Dr. Sandro Pinto for giving me the opportunity to develop this groundbreaking work and for all the guidance and continuous support throughout this great journey. Thank you for all the confidence placed on me, and especially, for all the motivation and advices given during difficult times. I would like to also thank Dr. Adriano Tavares, my professor, whom I appreciate all the given advices and reviews. And of course, thanks for all the music tips that helped me to increase productivity.