Real-Time Operating Systems and Programming Languages for Embedded Systems

In this chapter, we present the different alternatives that are available today for the development of real-time embedded systems. In particular, we will focus on the programming languages use like C++, Java and Ada and the operating systems like Linux-RT, FreeRTOS, TinyOS, etc. In particular we will analyze the actual state of the art for developing embedded systems under the WORA paradigm with standard Java [1], its Real-Time Specification and with the use of Real-Time Core Extensions and pico Java based CPUs [5]. We expect the reader to have a clear view of the opportunities present at the moment of starting a design with its pros and cons so it can choose the best one to fit its case.Fil: Orozco, Javier Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Laboratorio de Sistemas Digitales; ArgentinaFil: Santos, Rodrigo Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Laboratorio de Sistemas Digitales; Argentin

A Hardware Time Manager Implementation for the Xenomai Real-Time Kernel of Embedded Linux

Nowadays, the use of embedded operating systems in different embedded projects is subject to a tremendous growth. Embedded Linux is becoming one of those most popular EOSs due to its modularity, efficiency, reliability, and cost. One way to make it hard real-time is to include a real-time kernel like Xenomai. One of the key characteristics of a Real-Time Operating System (RTOS) is its ability to meet execution time deadlines deterministically. So, the more precise and flexible the time management can be, the better it can handle efficiently the determinism for different embedded applications. RTOS time precision is characterized by a specific periodic interrupt service controlled by a software time manager. The smaller the period of the interrupt, the better the precision of the RTOS, the more it overloads the CPU, and though reduces the overall efficiency of the RTOS. In this paper, we propose to drastically reduce these overheads by migrating the time management service of Xenomai into a configurable hardware component to relieve the CPU. The hardware component is implemented in a Field Programmable Gate Array coupled to the CPU. This work was achieved in a Master degree project where students could apprehend many fields of embedded systems: RTOS programming, hardware design, performance evaluation, etc.Comment: Embed With Linux (EWiLi) workshop, Lorient : France (2012

On-Device Deep Learning Inference for System-on-Chip (SoC) Architectures

As machine learning becomes ubiquitous, the need to deploy models on real-time, embedded systems will become increasingly critical. This is especially true for deep learning solutions, whose large models pose interesting challenges for target architectures at the “edge” that are resource-constrained. The realization of machine learning, and deep learning, is being driven by the availability of specialized hardware, such as system-on-chip solutions, which provide some alleviation of constraints. Equally important, however, are the operating systems that run on this hardware, and specifically the ability to leverage commercial real-time operating systems which, unlike general purpose operating systems such as Linux, can provide the low-latency, deterministic execution required for embedded, and potentially safety-critical, applications at the edge. Despite this, studies considering the integration of real-time operating systems, specialized hardware, and machine learning/deep learning algorithms remain limited. In particular, better mechanisms for real-time scheduling in the context of machine learning applications will prove to be critical as these technologies move to the edge. In order to address some of these challenges, we present a resource management framework designed to provide a dynamic on-device approach to the allocation and scheduling of limited resources in a real-time processing environment. These types of mechanisms are necessary to support the deterministic behavior required by the control components contained in the edge nodes. To validate the effectiveness of our approach, we applied rigorous schedulability analysis to a large set of randomly generated simulated task sets and then verified the most time critical applications, such as the control tasks which maintained low-latency deterministic behavior even during off-nominal conditions. The practicality of our scheduling framework was demonstrated by integrating it into a commercial real-time operating system (VxWorks) then running a typical deep learning image processing application to perform simple object detection. The results indicate that our proposed resource management framework can be leveraged to facilitate integration of machine learning algorithms with real-time operating systems and embedded platforms, including widely-used, industry-standard real-time operating systems

Control-Flow Integrity for Real-Time Embedded Systems

Attacks on real-time embedded systems can endanger lives and critical infrastructure. Despite this, techniques for securing embedded systems software have not been widely studied. Many existing security techniques for general-purpose computers rely on assumptions that do not hold in the embedded case. This paper focuses on one such technique, control-flow integrity (CFI), that has been vetted as an effective countermeasure against control-flow hijacking attacks on general-purpose computing systems. Without the process isolation and fine-grained memory protections provided by a general-purpose computer with a rich operating system, CFI cannot provide any security guarantees. This work proposes RECFISH, a system for providing CFI guarantees on ARM Cortex-R devices running minimal real-time operating systems. We provide techniques for protecting runtime structures, isolating processes, and instrumenting compiled ARM binaries with CFI protection. We empirically evaluate RECFISH and its performance implications for real-time systems. Our results suggest RECFISH can be directly applied to binaries without compromising real-time performance; in a test of over six million realistic task systems running FreeRTOS, 85% were still schedulable after adding RECFISH

EOS: A project to investigate the design and construction of real-time distributed embedded operating systems

The EOS project is investigating the design and construction of a family of real-time distributed embedded operating systems for reliable, distributed aerospace applications. Using the real-time programming techniques developed in co-operation with NASA in earlier research, the project staff is building a kernel for a multiple processor networked system. The first six months of the grant included a study of scheduling in an object-oriented system, the design philosophy of the kernel, and the architectural overview of the operating system. In this report, the operating system and kernel concepts are described. An environment for the experiments has been built and several of the key concepts of the system have been prototyped. The kernel and operating system is intended to support future experimental studies in multiprocessing, load-balancing, routing, software fault-tolerance, distributed data base design, and real-time processing

Control-Flow Integrity on Real-Time Embedded Systems

While security protections continue to be developed for general-purpose computers,real-time computing has remained unprotected against control-flow hijacking attacks.Existing solutions rely on hardware unavailable to embedded systems due to the cost, or impose excessive overhead, leaving real-time applications unable to operate within their time constraints. We propose RECFISH++, a Control-Flow Integrity implementation focused on protecting real-time embedded systems. By modifying LLVM and FreeRTOS, a popular compiler back-end and real-time operating system, we provide an end-to-end solution for protecting any real-time application on the ARM Cortex-M microprocessor against control-flow hijacking attacks

Building real-time embedded applications on QduinoMC: a web-connected 3D printer case study

Single Board Computers (SBCs) are now emerging with multiple cores, ADCs, GPIOs, PWM channels, integrated graphics, and several serial bus interfaces. The low power consumption, small form factor and I/O interface capabilities of SBCs with sensors and actuators makes them ideal in embedded and real-time applications. However, most SBCs run non-realtime operating systems based on Linux and Windows, and do not provide a user-friendly API for application development. This paper presents QduinoMC, a multicore extension to the popular Arduino programming environment, which runs on the Quest real-time operating system. QduinoMC is an extension of our earlier single-core, real-time, multithreaded Qduino API. We show the utility of QduinoMC by applying it to a specific application: a web-connected 3D printer. This differs from existing 3D printers, which run relatively simple firmware and lack operating system support to spool multiple jobs, or interoperate with other devices (e.g., in a print farm). We show how QduinoMC empowers devices with the capabilities to run new services without impacting their timing guarantees. While it is possible to modify existing operating systems to provide suitable timing guarantees, the effort to do so is cumbersome and does not provide the ease of programming afforded by QduinoMC.http://www.cs.bu.edu/fac/richwest/papers/rtas_2017.pdfAccepted manuscrip

Real-Time FPGA-Based Systems to Remote Monitoring

Some industrial and laboratory applications such as control, monitoring, test and measurements, and automation require real-time systems for their development. Embedded systems for acquisition and processing often require the participation of the embedded operating system and therefore are necessary techniques that can accelerate software execution. The latest field-programmable gate arrays’ (FPGA) technology has blurred the distinction between hardware and software with embedded processors that allow the development of Systems-on-a-Chip (SoC) running on operating systems. The widespread adoption of wireless technologies such as Bluetooth, ZigBee, and Wi-Fi in the last years has facilitated the use of these technologies to the development of real-time monitoring applications that combined with FPGA devices which has the advantages of low cost, flexibility, and scalability as compared with other commercial systems

An experiment with RTEMS

The Real-Time Executive for Multiprocessor Systems (RTEMS) is an open source real-time executive used in many embedded systems. This report describes our effort to gain hands-on experience with RTEMS and provides instructions on how to build and use RTEMS in two different operating environments.Approved for public release; distribution is unlimited

Control-flow Integrity for Real-time Embedded Systems

As embedded systems become more connected and more ubiquitous in mission- and safety-critical systems, embedded devices have become a high- value target for hackers and security researchers. Attacks on real-time embedded systems software can put lives in danger and put our critical infrastructure at risk. Despite this, security techniques for embedded systems have not been widely studied. Many existing software security techniques for general purpose computers rely on assumptions that do not hold in the embedded case. This thesis focuses on one such technique, control-flow integrity (CFI), that has been vetted as an effective countermeasure against control-flow hijacking attacks on general purpose computing systems. Without the process isolation and fine-grained memory protections provided by a general purpose computer with a rich operating system, CFI cannot provide any security guarantees. This thesis explores a way to use CFI on ARM Cortex-R devices running minimal real-time operating systems. We provide techniques for protecting runtime structures, isolating processes, and instrumenting compiled ARM binaries with CFI protection