Secure Microkernel for Deeply Embedded Devices
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A Microkernel API for Fine-Grained Decomposition
A Microkernel API for Fine-Grained Decomposition Sebastian Reichelt Jan Stoess Frank Bellosa System Architecture Group, University of Karlsruhe, Germany freichelt,stoess,[email protected] ABSTRACT from the microkernel APIs in existence. The need, for in- Microkernel-based operating systems typically require spe- stance, to explicitly pass messages between servers, or the cial attention to issues that otherwise arise only in dis- need to set up threads and address spaces in every server for tributed systems. The resulting extra code degrades per- parallelism or protection require OS developers to adopt the formance and increases development effort, severely limiting mindset of a distributed-system programmer rather than to decomposition granularity. take advantage of their knowledge on traditional OS design. We present a new microkernel design that enables OS devel- Distributed-system paradigms, though well-understood and opers to decompose systems into very fine-grained servers. suited for physically (and, thus, coarsely) partitioned sys- We avoid the typical obstacles by defining servers as light- tems, present obstacles to the fine-grained decomposition weight, passive objects. We replace complex IPC mecha- required to exploit the benefits of microkernels: First, a nisms by a simple function-call approach, and our passive, lot of development effort must be spent into matching the module-like server model obviates the need to create threads OS structure to the architecture of the selected microkernel, in every server. Server code is compiled into small self- which also hinders porting existing code from monolithic sys- contained files, which can be loaded into the same address tems. Second, the more servers exist | a desired property space (for speed) or different address spaces (for safety). -
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. -
Run-Time Reconfigurable RTOS for Reconfigurable Systems-On-Chip
Run-time Reconfigurable RTOS for Reconfigurable Systems-on-Chip Dissertation A thesis submited to the Faculty of Computer Science, Electrical Engineering and Mathematics of the University of Paderborn and to the Graduate Program in Electrical Engineering (PPGEE) of the Federal University of Rio Grande do Sul in partial fulfillment of the requirements for the degree of Dr. rer. nat. and Dr. in Electrical Engineering Marcelo G¨otz November, 2007 Supervisors: Prof. Dr. rer. nat. Franz J. Rammig, University of Paderborn, Germany Prof. Dr.-Ing. Carlos E. Pereira, Federal University of Rio Grande do Sul, Brazil Public examination in Paderborn, Germany Additional members of examination committee: Prof. Dr. Marco Platzner Prof. Dr. Urlich R¨uckert Dr. Mario Porrmann Date: April 23, 2007 Public examination in Porto Alegre, Brazil Additional members of examination committee: Prof. Dr. Fl´avioRech Wagner Prof. Dr. Luigi Carro Prof. Dr. Altamiro Amadeu Susin Prof. Dr. Leandro Buss Becker Prof. Dr. Fernando Gehm Moraes Date: October 11, 2007 Acknowledgements This PhD thesis was carried out, in his great majority, at the Department of Computer Science, Electrical Engineering and Mathematics of the University of Paderborn, during my time as a fellow of the working group of Prof. Dr. Franz J. Rammig. Due to a formal agreement between Federal University of Rio Grande do Sul (UFRGS) and University of Paderborn, I had the opportunity to receive a bi-national doctoral degree. Therefore, I had to accomplished, in addition, the PhD Graduate Program in Electrical Engineering of UFRGS. So, I hereby acknowledge, without mention everyone personally, all persons involved in making this agreement possible. -
Introduction
1 INTRODUCTION A modern computer consists of one or more processors, some main memory, disks, printers, a keyboard, a mouse, a display, network interfaces, and various other input/output devices. All in all, a complex system.oo If every application pro- grammer had to understand how all these things work in detail, no code would ever get written. Furthermore, managing all these components and using them optimally is an exceedingly challenging job. For this reason, computers are equipped with a layer of software called the operating system, whose job is to provide user pro- grams with a better, simpler, cleaner, model of the computer and to handle manag- ing all the resources just mentioned. Operating systems are the subject of this book. Most readers will have had some experience with an operating system such as Windows, Linux, FreeBSD, or OS X, but appearances can be deceiving. The pro- gram that users interact with, usually called the shell when it is text based and the GUI (Graphical User Interface)—which is pronounced ‘‘gooey’’—when it uses icons, is actually not part of the operating system, although it uses the operating system to get its work done. A simple overview of the main components under discussion here is given in Fig. 1-1. Here we see the hardware at the bottom. The hardware consists of chips, boards, disks, a keyboard, a monitor, and similar physical objects. On top of the hardware is the software. Most computers have two modes of operation: kernel mode and user mode. The operating system, the most fundamental piece of soft- ware, runs in kernel mode (also called supervisor mode). -
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. -
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 -
Microkernel Construction Introduction
Microkernel Construction Introduction Nils Asmussen 04/06/2017 1 / 28 Outline Introduction Goals Administration Monolithic vs. Microkernel Overview About L4/NOVA 2 / 28 Goals 1 Provide deeper understanding of OS mechanisms 2 Look at the implementation details of microkernels 3 Make you become enthusiastic microkernel hackers 4 Propaganda for OS research at TU Dresden 3 / 28 Administration Thursday, 4th DS, 2 SWS Slides: www.tudos.org ! Teaching ! Microkernel Construction Subscribe to our mailing list: www.tudos.org/mailman/listinfo/mkc2017 In winter term: Microkernel-based operating systems (MOS) Various labs 4 / 28 Outline Introduction Monolithic vs. Microkernel Kernel design comparison Examples for microkernel-based systems Vision vs. Reality Challenges Overview About L4/NOVA 5 / 28 Monolithic Kernel System Design u s Application Application Application e r k Kernel e r File Network n e Systems Stacks l m Memory Process o Drivers Management Management d e Hardware 6 / 28 Monolithic Kernel OS (Propaganda) System components run in privileged mode No protection between system components Faulty driver can crash the whole system Malicious app could exploit bug in faulty driver More than 2=3 of today's OS code are drivers No need for good system design Direct access to data structures Undocumented and frequently changing interfaces Big and inflexible Difficult to replace system components Difficult to understand and maintain Why something different? ! Increasingly difficult to manage growing OS complexity 7 / 28 Microkernel System Design Application -
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 -
Operating System Verification—An Overview
Sadhan¯ a¯ Vol. 34, Part 1, February 2009, pp. 27–69. © Printed in India Operating system verification—An overview GERWIN KLEIN Sydney Research Laboratory, NICTA,∗ Australia, School of Computer Science and Engineering, University of New South Wales, Sydney, Australia e-mail: [email protected] Abstract. This paper gives a high-level introduction to the topic of formal, interactive, machine-checked software verification in general, and the verification of operating systems code in particular. We survey the state of the art, the advantages and limitations of machine-checked code proofs, and describe two specific ongoing larger-scale verification projects in more detail. Keywords. Formal software verification; operating systems; theorem proving. 1. Introduction The fastest, cheapest and easiest way to build something is properly the first time (Parker 2007). This engineer’s credo has made it into popular literature, but it seems to be largely ignored in the world of software development. In the late 1960s a software crisis was diagnosed on a summit in the Bavarian Alps (Naur & Randell 1969): Software was getting more and more complex, and we had no structured way of building it. We ended up with projects that took significantly longer than planned, were more expensive than planned, delivered results that did not fully address customer needs, or at worst were useless. This summit in the late 1960s is widely seen as the birth of the discipline of software engineering. Now, almost 40 years later, we have come a long way. There are numerous books on software engineering, a plenitude of methodologies, programming languages, and processes to choose from. -
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 -
Analysis of Existing Dynamic Software Updating Techniques for Safe and Secure Industrial Control Systems
I. Mugarza, et al., Int. J. of Safety and Security Eng., Vol. 8, No. 1 (2018) 121–131 ANALYSIS OF EXISTING DYNAMIC SOFTWARE UPDATING TECHNIQUES FOR SAFE AND SECURE INDUSTRIAL CONTROL SYSTEMS IMANOL MUGARZA1, JORGE PARRA1 & EDUARDO JACOB2 1 IK4-Ikerlan Technology Research Centre, Dependable Embedded Systems Area. 2 Faculty of Engineering, University of the Basque Country UPV/EHU. ABSTRACT Higher interconnectivity among devices, machines, the cloud and humans is envisioned in the actual trend of automation, also known as Industrial Internet of Things (IIoT). These industrial control systems, which may require high availability and/or safety related capabilities, are no longer isolated from the corporate environment or Internet. Software updates will be needed during the product life cycle, due to the long service life, the increasing number of security related vulnerabilities discovered on these industrial control systems and the high interconnectivity desired in IIoT. These updates aim at fixing all these security weaknesses, bugs and vulnerabilities that could appear, while the required safety integrity levels are ensured. Security-related concerns have just been addressed by the safety engineering community, because of the increasing number of cyber-attacks against safety-critical systems, such as Stuxnet. Moreover, system shut-downs caused by software updates could not be plausible when high availability is required. Typically, in order to perform the software update, the whole industrial process or the production is halted, so that the software upgrade is safely applied. However, this scenario might not be applied in critical infrastructures, such as nuclear or hydro- electrical power plants, where these production and service interruptions are not acceptable from the business and service point of view.