Leandro Fiorin

Secure Memory Accesses on Networks-on-Chip

Security is gaining increasing relevance in the development of embedded devices. Towards a secure system at each level of design, this paper addresses security aspects related to network-on-chip (NoC) architectures, foreseen as the communication infrastructure of next-generation embedded devices. In the context of NoC-based multiprocessor systems, we focus on the topic, not yet thoroughly faced, of data protection. In this paper, we present a secure NoC architecture composed of a set of data protection units (DPUs) implemented within the network interfaces. The run-time configuration of the programmable part of the DPUs is managed by a central unit, the network security manager (NSM). The DPU, similar to a firewall, can check and limit the access rights (none, read, write, or both) of processors accessing data and instructions in a shared memory - in particular distinguishing between the operating roles (supervisor/user and secure/unsecure) of the processing elements. We explore different alternative implementations for the DPU and demonstrate how this unit does not affect the network latency if the memory request has the appropriate rights. We also focus on the dynamic updating of the DPUs to support their utilization in dynamic environments, and on the utilization of authentication techniques to increase the level of security.

Online task remapping strategies for fault-tolerant Network-on-Chip multiprocessors

As CMOS technology scales down into the deep-submicron domain, the aspects of fault tolerance in complex Networks-on-Chip (NoCs) architectures are assuming an increasing relevance. Task remapping is a software based solution for dealing with permanent failures in processing elements in the NoC. In this work, we formulate the optimal task mapping problem for mesh-based NoC multiprocessors with deterministic routing as an integer linear programming (ILP) problem with the objective of minimizing the communication traffic in the system and the total execution time of the application. We find the optimal mappings at design time for all scenarios where single-faults occur in the processing nodes. We propose heuristics for the online task remapping problem and compare their performance with the optimal solutions.

A security monitoring service for NoCs

As computing and communications increasingly pervade our lives, security and protection of sensitive data and systems are emerging as extremely important issues. Networks-on-Chip (NoCs) have appeared as design strategy to cope with the rapid increase in complexity of Multiprocessor Systems-on-Chip (MPSoCs), but only recently research community have addressed security on NoC-based architectures. In this paper, we present a monitoring system for NoC based architectures, whose goal is to help detect security violations carried out against the system. Information collected are sent to a central unit for efficiently counteracting actions performed by attackers. We detail the design of the basic blocks and analyse overhead associated with the ASIC implementation of the monitoring system, discussing type of security threats that it can help detect and counteract.

A data protection unit for NoC-based architectures

Security is gaining increasing relevance in the development of embedded devices. Towards a secure system at each level of design, this paper addresses the security aspects related to Network-on-Chip (NoC) architectures, foreseen as the communication infrastructure of next-generation embedded devices. In the context of NoC-based Multiprocessor systems, we focus on the topic, not thoroughly faced yet, of data protection. We present the architecture of a Data Protection Unit (DPU) designed for implementation within the Network Interface (NI). The DPU supports the capability to check and limit the access rights (none, read, write or both) of processors requesting access to data locations in a shared memory - in particular distinguishing between the operating roles (supervisor or user) of processing elements. We explore different alternative implementations and demonstrate how the DPU unit does not affect the network latency if the memory request has the appropriate rights. In the experimental section we show synthesis results for different ASIC implementations of the Data Protection Unit.

An Automated Design Flow for NoC-based MPSoCs on FPGA

Increased dynamics of the embedded devices market makes reduced time-to-market emerge as one of most challenging tasks in modern embedded system design. The complexity of Multiprocessor Systems-on-Chip (MPSoCs) rapidly increases and Networks-on-Chips (NoCs) have emerged as design strategy to cope with it. In order to allow fast generation of these platforms in the development phase, a full design flow is required. On the other hand, modern FPGAs provide the possibility for fast and low-cost prototyping, representing an efficient response to these needs. In this paper we present a framework, based on the Xilinx Embedded Development Kit (EDK) design flow, for the generation of MPSoCs based on NoCs. The tool provides system designers with the possibility to easily and quickly generate desired architectures that can be helpful for testing, debugging and verifying purposes. Our integrated design flow takes as input a textual description of the system and produces as final result a configuration bitstream file. The framework has been tested and verified on a Xilinx Virtex-II Pro board.

MPSoCs run-time monitoring through networks-on-chip

Networks-on-Chip (NoCs) have appeared as design strategy to overcome the limitations, in terms of scalability, efficiency, and power consumption of current buses. In this paper, we discuss the idea of using NoCs to monitor system behaviour at run-time by tracing activities at initiators and targets. Main goal of the monitoring system is to retrieve information useful for run-time optimization and resources allocation in adaptive systems. Information detected by probes embedded within NIs is sent to a central unit, in charge of collecting and elaborating the data. We detail the design of the basic blocks and analyse the overhead associated with the ASIC implementation of the monitoring system, as well as discussing implications in terms of the additional traffic generated in the NoC.

Security Aspects in Networks-on-Chips: Overview and Proposals for Secure Implementations

Security has gained increasing relevance in the development of embedded devices. Towards the aim of a secure system at each level of the design, in this paper we address security aspects related to networks-on-chips (NoCs) architectures. After presenting the attacks most likely to address NoCs, we survey existing academic and industrial secure architectures relevant to our case, focusing in particular on their communication infrastructure. We outline and propose possible solutions to contrast some of the attacks described and suggest the use of the NoC as a mean to monitor and detect unexpected system behaviors.

System Adaptivity and Fault-Tolerance in NoC-based MPSoCs: The MADNESS Project Approach

Modern embedded systems increasingly require adaptive run-time management. The system may adapt the mapping of the applications in order to accommodate the current workload conditions, to balance load for efficient resource utilization, to meet quality of service agreements, to avoid thermal hot-spots and to reduce power consumption. As the possibility of experiencing run-time faults becomes increasingly relevant with deep-sub-micron technology nodes, in the scope of the MADNESS project, we focus particularly on the problem of graceful degradation by dynamic remapping in presence of run-time faults. In this paper, we summarize the major results achieved in the MADNESS project until now regarding the system adaptivity and fault tolerant processing. We report the first results of the integration between platform level and middleware level support for adaptivity and fault tolerance. A case study demonstrates the survival ability of the system via a low-overhead process migration mechanism and a near-optimal online remapping heuristic.

Design of Fault Tolerant Network Interfaces for NoCs

Networks-on-Chip (NoCs) appeared as a strategy to deal with the communication requirements of complex IP-based System-on-Chips. As the complexity of designs increases and the technology scales down into the deep-submicron domain, the probability of malfunctions and failures in the NoC components increases. This paper focuses on the study and evaluation of techniques for increasing reliability and resilience of Network Interfaces (NIs). NIs act as interfaces between IP cores and the communication infrastructure, a faulty behavior in them could affect therefore the overall system. In this work, we propose a functional fault model for the NI components, and we present a two-level fault tolerant solution that can be employed for mitigating the effects of both single-event upset soft errors and hard errors on the NI. Experiments show that with a limited overhead we can obtain a significant reliability of the NI, while saving up to 83% in area with respect to a standard Triple Modular Redundancy implementation, as well as a significant energy reduction.

A monitoring system for NoCs

In this paper, we propose and discuss a monitoring architecture for Networks-on-Chip (NoCs) that provides system information useful for helping designers in efficiently exploiting resources available in new complex Multiprocessor System-on-Chip (MPSoC) platforms, and in understanding their behavior. We focus on the analysis of the architectural details and design challenges of such systems, by describing powerful tools for detecting information that can be used both at run-time for detecting dynamic changes in system behavior and at post-execution time for debugging and profiling of applications. We detail the design of the probes monitoring the events and discuss an architecture for collection, storage, and analysis of information generated by them. We evaluate cost of the implementation of the system in terms of area and traffic overhead, and we present results obtained when monitoring a use-case multimedia application.1