Simulating the effects of logic faults in implementation-level VITAL-compliant models

[EN] Simulation-based fault injection is a well-known technique to assess the dependability of hardware designs specified using hardware description languages (HDL). Although logic faults are usually introduced in models defined at the register transfer level (RTL), most accurate results can be obtained by considering implementation-level ones, which reflect the actual structure and timing of the circuit. These models consist of a list of interconnected technology-specific components (macrocells), provided by vendors and annotated with post-place-and-route delays. Macrocells described in the very high speed integrated circuit HDL (VHDL) should also comply with the VHDL initiative towards application specific integrated circuit libraries (VITAL) standard to be interoperable across standard simulators. However, the rigid architecture imposed by VITAL makes that fault injection procedures applied at RTL cannot be used straightforwardly. This work identifies a set of generic operations on VITAL-compliant macrocells that are later used to define how to accurately simulate the effects of common logic fault models. The generality of this proposal is supported by the definition of a platform-specific fault procedure based on these operations. Three embedded processors, implemented using the Xilinx¿s toolchain and SIMPRIM library of macrocells, are considered as a case study, which exposes the gap existing between the robustness assessment at both RTL and implementation-level.This work has been partially funded by the Ministerio de Economia, Industria y Competitividad of Spain under grant agreement no TIN2016-81075-R, and the "Programa de Ayudas de Investigacion y Desarrollo" (PAID) of Universitat Politecnica de Valencia.Tuzov, I.; De-Andrés-Martínez, D.; Ruiz, JC. (2019). Simulating the effects of logic faults in implementation-level VITAL-compliant models. Computing. 101(2):77-96. https://doi.org/10.1007/s00607-018-0651-4S77961012Baraza JC, Gracia J, Blanc S, Gil D, Gil P (2008) Enhancement of fault injection techniques based on the modification of vhdl code. IEEE Tran Very Large Scale Integr Syst 16:693–706Baraza JC, Gracia J, Gil D, Gil P (2002) A prototype of a vhdl-based fault injection tool: description and application. Journal of Systems Architecture 47(10):847–867Benites LAC, Kastensmidt FL (2017) Fault injection methodology for single event effects on clock-gated asics. In: IEEE Latin American test symposium. IEEE, pp 1–4Benso A, Prinetto P (2003) Fault injection techniques and tools for VLSI reliability evaluation. Frontiers in electronic testing. Kluwer Academic Publishers, BerlinCobham Gaisler AB: LEON3 processor product sheet (2016). https://www.gaisler.com/doc/leon3_product_sheet.pdfCohen B (2012) VHDL coding styles and methodologies. 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Automated Synthesis of SEU Tolerant Architectures from OO Descriptions

SEU faults are a well-known problem in aerospace environment but recently their relevance grew up also at ground level in commodity applications coupled, in this frame, with strong economic constraints in terms of costs reduction. On the other hand, latest hardware description languages and synthesis tools allow reducing the boundary between software and hardware domains making the high-level descriptions of hardware components very similar to software programs. Moving from these considerations, the present paper analyses the possibility of reusing Software Implemented Hardware Fault Tolerance (SIHFT) techniques, typically exploited in micro-processor based systems, to design SEU tolerant architectures. The main characteristics of SIHFT techniques have been examined as well as how they have to be modified to be compatible with the synthesis flow. A complete environment is provided to automate the design instrumentation using the proposed techniques, and to perform fault injection experiments both at behavioural and gate level. Preliminary results presented in this paper show the effectiveness of the approach in terms of reliability improvement and reduced design effort

Validation of a software dependability tool via fault injection experiments

Presents the validation of the strategies employed in the RECCO tool to analyze a C/C++ software; the RECCO compiler scans C/C++ source code to extract information about the significance of the variables that populate the program and the code structure itself. Experimental results gathered on an Open Source Router are used to compare and correlate two sets of critical variables, one obtained by fault injection experiments, and the other applying the RECCO tool, respectively. Then the two sets are analyzed, compared, and correlated to prove the effectiveness of RECCO's methodology

Enhancement of fault injection techniques based on the modification of VHDL code

Deep submicrometer devices are expected to be increasingly sensitive to physical faults. For this reason, fault-tolerance mechanisms are more and more required in VLSI circuits. So, validating their dependability is a prior concern in the design process. Fault injection techniques based on the use of hardware description languages offer important advantages with regard to other techniques. First, as this type of techniques can be applied during the design phase of the system, they permit reducing the time-to-market. Second, they present high controllability and reachability. Among the different techniques, those based on the use of saboteurs and mutants are especially attractive due to their high fault modeling capability. However, implementing automatically these techniques in a fault injection tool is difficult. Especially complex are the insertion of saboteurs and the generation of mutants. In this paper, we present new proposals to implement saboteurs and mutants for models in VHDL which are easy-to-automate, and whose philosophy can be generalized to other hardware description languages.Baraza Calvo, JC.; Gracia-Morán, J.; Blanc Clavero, S.; Gil Tomás, DA.; Gil Vicente, PJ. (2008). Enhancement of fault injection techniques based on the modification of VHDL code. IEEE Transactions on Very Large Scale Integration (VLSI) Systems. 16(6):693-706. doi:10.1109/TVLSI.2008.2000254S69370616

Injecting Intermittent Faults for the Dependability Assessment of a Fault-Tolerant Microcomputer System

© 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.As scaling is more and more aggressive, intermittent faults are increasing their importance in current deep submicron complementary metal-oxide-semiconductor (CMOS) technologies. This work shows the dependability assessment of a fault-tol- erant computer system against intermittent faults. The applied methodology lies in VHDL-based fault injection, which allows the assessment in early design phases, together with a high level of observability and controllability. The evaluated system is a duplex microcontroller system with cold stand-by sparing. A wide set of intermittent fault models have been injected, and from the simulation traces, coverages and latencies have been measured. Markov models for this system have been generated and some dependability functions, such as reliability and safety, have been calculated. From these results, some enhancements of detection and recovery mechanisms have been suggested. The methodology presented is general to any fault-tolerant computer system.This work was supported in part by the Universitat Politecnica de Valencia under the Research Project SP20120806, and in part by the Spanish Government under the Research Project TIN2012-38308-C02-01. Associate Editor: J. Shortle.Gil Tomás, DA.; Gracia Morán, J.; Baraza Calvo, JC.; Saiz Adalid, LJ.; Gil Vicente, PJ. (2016). Injecting Intermittent Faults for the Dependability Assessment of a Fault-Tolerant Microcomputer System. IEEE Transactions on Reliability. 65(2):648-661. https://doi.org/10.1109/TR.2015.2484058S64866165

Effects of intermittent faults on the reliability of a Reduced Instruction Set Computing (RISC) microprocessor

© 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.With the scaling of complementary metal-oxide-semiconductor (CMOS) technology to the submicron range, designers have to deal with a growing number and variety of fault types. In this way, intermittent faults are gaining importance in modern very large scale integration (VLSI) circuits. The presence of these faults is increasing due to the complexity of manufacturing processes (which produce residues and parameter variations), together with special aging mechanisms. This work presents a case study of the impact of intermittent faults on the behavior of a reduced instruction set computing (RISC) microprocessor. We have carried out an exhaustive reliability assessment by using very-high-speed-integrated-circuit hardware description language (VHDL)-based fault injection. In this way, we have been able to modify different intermittent fault parameters, to select various targets, and even, to compare the impact of intermittent faults with those induced by transient and permanent faults.This work was supported by the Spanish Government under the Research Project TIN2009-13825 and by the Universitat Politecnica de Valencia under the Project SP20120806. Associate Editor: L. Cui.Gracia-Morán, J.; Baraza Calvo, JC.; Gil Tomás, DA.; Saiz-Adalid, L.; Gil, P. (2014). Effects of intermittent faults on the reliability of a Reduced Instruction Set Computing (RISC) microprocessor. IEEE Transactions on Reliability. 63(1):144-153. https://doi.org/10.1109/TR.2014.2299711S14415363

Statistical Reliability Estimation of Microprocessor-Based Systems

What is the probability that the execution state of a given microprocessor running a given application is correct, in a certain working environment with a given soft-error rate? Trying to answer this question using fault injection can be very expensive and time consuming. This paper proposes the baseline for a new methodology, based on microprocessor error probability profiling, that aims at estimating fault injection results without the need of a typical fault injection setup. The proposed methodology is based on two main ideas: a one-time fault-injection analysis of the microprocessor architecture to characterize the probability of successful execution of each of its instructions in presence of a soft-error, and a static and very fast analysis of the control and data flow of the target software application to compute its probability of success. The presented work goes beyond the dependability evaluation problem; it also has the potential to become the backbone for new tools able to help engineers to choose the best hardware and software architecture to structurally maximize the probability of a correct execution of the target softwar

Study of the effects of SEU-induced faults on a pipeline protected microprocessor

This paper presents a detailed analysis of the behavior of a novel fault-tolerant 32-bit embedded CPU as compared to a default (non-fault-tolerant) implementation of the same processor during a fault injection campaign of single and double faults. The fault-tolerant processor tested is characterized by per-cycle voting of microarchitectural and the flop-based architectural states, redundancy at the pipeline level, and a distributed voting scheme. Its fault-tolerant behavior is characterized for three different workloads from the automotive application domain. The study proposes statistical methods for both the single and dual fault injection campaigns and demonstrates the fault-tolerant capability of both processors in terms of fault latencies, the probability of fault manifestation, and the behavior of latent faults

A Fault Injection Environment for Microprocessor-based Board

Evaluating the faulty behaviour of low-cost microprocessor-based boards is an increasingly important issue, due to their usage in many safety critical systems. To address this issue, the paper describes a software-implemented fault injection system based on the trace exception mode available in most microprocessors. The architecture of the complete fault injection environment is proposed, integrating modules for generating a fault list, for performing their injection and for gathering the results, respectively. Data gathered from some sample benchmark applications are presented The main advantages of the approach are low cost, good portability, and high efficienc

Black Box Model based Self Healing Solution for Stuck at Faults in Digital Circuits

The paper proposes a design strategy to retain the true nature of the output in the event of occurrence of stuck at faults at the interconnect levels of digital circuits. The procedure endeavours to design a combinational architecture which includes attributes to identify stuck at faults present in the intermediate lines and involves a healing mechanism to redress the same. The simulated fault injection procedure introduces both single as well as multiple stuck-at faults at the interconnect levels of a two level combinational circuit in accordance with the directives of a control signal. The inherent heal facility attached to the formulation enables to reach out the fault free output even in the presence of faults. The Modelsim based simulation results obtained for the Circuit Under Test [CUT] implemented using a Read Only Memory [ROM], proclaim the ability of the system to survive itself from the influence of faults. The comparison made with the traditional Triple Modular Redundancy [TMR] exhibits the superiority of the scheme in terms of fault coverage and area overhead.