F T -U NSHADES A design analysis tool based on Emulation Technologies ESA-ESTEC/17540 University of Sevilla-AICIA-ESA

Summary Fault Injection in general What is FT-UNSHADES? What is not FT-UNSHADES? Main features Models for design analysis Cycle accurate Smart table FT-UNSHADES for FPGA analysis What can FT-UNSHADES do for you? Using FT-UNSHADES Accessing to FTUNSHADES 11/09/2009FPGA workshop. ESA/ESTEC, Noordwijk

Fault Injection in general Certain Radiation Effects over digital circuits mainly affect to the stored information in Registers and Memories. These radiation effects are: Single Event Upset (one register is attacked) Single Event Transient (Due to propagation, one or several registers are attacked) Multi Bit Upsets (Several registers simultaneously due to Layout adjacence) These effects corrupt temporally the information processed by the silicon design. The corruption of the information due to these effects is because 0 changes into 1 or viceversa. This model is named bit-flip. FAULT INJECTION means reproduce the bit-flip in a dynamic execution of the circuit in order to analyze its behavior FAULT INJECTION needs two mechanisms: A platform that executes the circuit A method for producing a bit-flip in time. 11/09/2009FPGA workshop. ESA/ESTEC, Noordwijk

Using Run-Time reconfiguration for FAULT INJECTION The execution is made using an SRAM-FPGA from Xilinx The injection is performed using the configuration circuit The injection is made modifying either the REGISTER CONTENTS or THE CONFIGURATION CIRCUIT 11/09/2009FPGA workshop. ESA/ESTEC, Noordwijk Configuration memory Implemented design Configured elements Modify the register content Modify the design behavior Injection over user registers Injection over Config memory

What is FTUNSHADES? A Fault Injection system based on the concepts related to hardware debugging: observability and controlability*. The method is non intrusive. The design is analyzed with little modifications. Deterministic procedure of bit-flip insertion. The design is analyzed using a stimuli set or application (workload) Analysis of a design reliability attacking register, memory elements or configuration bits. The results are analyzed form design behavior point of view. A hardware accelerator allows to speed up the analysis. (This is the meaning of emulation, instead of simulation) Massive injection campaign and detailed analysis of the design are performed in the same platform. 11/09/2009FPGA workshop. ESA/ESTEC, Noordwijk * in this context observability means accessing to internal values of the registers, at every clock cycle. Controlability is the possibility of perturbing the circuit at any time of the workload.

What is not FTUNSHADES? It is not a tool for technological analysis. The effects are not treated as physical phenomena. It is not exactly a tool for FPGA implementation analysis (but maybe…) It is not a system for setting up experiments inside a beam (but maybe...) 11/09/2009FPGA workshop. ESA/ESTEC, Noordwijk FTUNSHADES is a tool for reliability analysis over a logic description of a design, so it is technology independent.

Main features A design is treated using the Xilinx standard tools. The design flow can preserve the confidentiality of the design. The analysis is made by means of a time- location model: Time is a clock cycle of the application Location is the user register (DFF, or bit of memory or SRL16) where the bit flip will be inserted. The register selection is based on the hierarchical tree, allowing selective injection. 11/09/2009FPGA workshop. ESA/ESTEC, Noordwijk

How it works... DESIGN INPUT VECTORS (APPLICATION) INPUT VECTORS (APPLICATION) OUTPUTS DESIGN WORKLOAD 11/09/2009FPGA workshop. ESA/ESTEC, Noordwijk The starting point is a traditional simulation scheme over the structural netlist of the design. Input vectors are stored and inserted in a database. They will form the so called workload The design is converted to a fully equivalent netlist in a Xilinx technology. This step is extremely critical As an RTL equivalent netlist the consequences of the injections over the Xilinx netlist can be assumed in the original design

The model is similar to a system in an accelerator. Two identical instances of the design are implemented The inputs are stored in external memories and the outputs are compared between both instances The clock is the same. Both instances work in parallel The injection is always to the same instance. The other works for comparison. The register selection is made using a demapping information provided by Xilinx Time variable is also controlled Deterministic attack using the design hierarchical organization Standard model DESIGN WORKLOAD Emulator (FPGA) Comparator Gold Faulty 11/09/2009FPGA workshop. ESA/ESTEC, Noordwijk Comparator System Clock Workload inputs

The model is dedicated to microprocessor analysis. Outputs are stored in a memory: The table Inputs are stored in external memories Comparison are made using the table as a reference The injection is on the microprocessor netlist. Software redundancy techniques would recover the system using clock cycles The recovering is made using several extra instructions and the comparison is made using some recovery time. The clock accurate comparison would be relaxed using the smart controller module Smart Table Model μ PROC Software Emulator (FPGA) Comparator Faulty SMART CONTROLLER REFERENCE TABLE 11/09/2009FPGA workshop. ESA/ESTEC, Noordwijk Comparator System Clock Workload inputs

Structure of the system FT-UNSHADESFT-UNSHADES TNT INPUT VECTOR DATABASE BITSTREAM BIT ALLOCATION User Commands (Scripts) VCD format Session.log Excel Sheet Console 11/09/2009FPGA workshop. ESA/ESTEC, Noordwijk

FT-UNSHADES Analysis Example CLOCK: REGISTER:leon0_mcore0_proc0_cx.c0_icache0_r.waddress_16 DAMAGE DETECTED: YES LATENCY: 1 CLK PORT: address A step by step analysis can be done, dump the data in VCD format and visualize the fault evolution with a waveform viewer Fault Inj. Error Detected After one clock cycle CLK 11/09/2009FPGA workshop. ESA/ESTEC, Noordwijk

This model Studies the behavior of the FPGA and the design under radiation The objective is to evaluate reliability of the design already implemented on a particular family of FPGA The results, for being considered valid, must comply several conditions: The FPGA has to belong to the same family than the target The design is firmly fixed in his place and route The attack points are constrained to a restricted area. An static analysis has to be performed previous to the dynamic analysis in order to define the database of critical configuration points. Again, the design and its workload refines this database, classifying the points as critical or not critical form dynamic point of view There is a strong dependence between Workload and the result of this refinement. FPGA analysis DESIGN WORKLOAD FPGA Comparator Gold Faulty DATABASE OF CRITICAL POINTS TNT 11/09/2009 FPGA workshop. ESA/ESTEC, Noordwijk !! Comparator System Clock Workload inputs Star-Rora alliance

What can FT-UNSHADES do for you? 1.FTUNSHADES will deeply analyze your modular protections using a fully deterministic fault injection method. 2.FTUNSHADES can optimize the redundancy insertion in your design. This can save area and power consumption. 3.FTUNSHADES can analyze reset net and initialization strategy 4.FTUNSHADES can provide an idea of the covering of the workload. The workload can be refined for further implementation in the acceleration test setup 5.FTUNSHADES can evaluate the strategy of redundancy in the software of an embedded processor and optimize the balance performance/area&consumption 6.FTUNSHADES allows the evaluation of the hardening of the place and route of a Xilinx FPGA. 11/09/2009FPGA workshop. ESA/ESTEC, Noordwijk

Relevant features Combine fault injection campaigns with detailed analysis Provide internal view of hierarchical module criticality Provide the possibility of analyzing the criticality considering application time A tool for optimizing the overhead of a mitigated design. Preserve confidentiality of design Experiences contrasted in Spanish National Accelerators Centre 11/09/2009FPGA workshop. ESA/ESTEC, Noordwijk

Experiences... Designs tested: Leon, Leon2 and Leon3 MicroBlaze 8051 Cordic 18x18x18 PicoBlaze RENASER RadTest device Other ESA benchmarks... Publications: TNS: 4, TIE:1, TIME:1.... Projects: RENASER, EMULASER, CELPAE, FTUNSHADES2,... 11/09/2009FPGA workshop. ESA/ESTEC, Noordwijk

Accessing to FTUNSHADES FTUNSHADES is managed by the RadUs team that belongs to the Electronic Engineering Group of the University of Sevilla The FTUNSHADES system is be offered to customers through an agreement with a company named AICIA The accessing framework is a service. The system can be accessed also remotely. Design secret is granted by NDA Training in the company Transfer of preparation tools Remote access or on site access if agreed Technical support 11/09/2009FPGA workshop. ESA/ESTEC, Noordwijk

Contacts AICIA University of Sevilla Camino de los Descubriumientos s/n Sevilla (SPAIN) 11/09/2009FPGA workshop. ESA/ESTEC, Noordwijk Hope to SEE you in RADECS 2011 !

SS1. Special Session on Ionizing Radiation Effects on Digital Devices for Safety Critical Industrial Applications Contacts: and special-sections 11/09/2009FPGA workshop. ESA/ESTEC, Noordwijk