Multiprocessor SoC systems have led to the increasing use of parallel hardware along with the associated software. These approaches have included coprocessor, homogeneous processor (e.g. SMP) and application specific architectures (i.e. DSP, ASIC). ASIPs have emerged as a viable alternative to conventional processing entities (PEs) due to its configurability and programmability. In this work, we introduce a heterogeneous multi-processor system using ASIPs as processing entities in a pipeline configuration. A streaming application is taken and manually broken into a series of algorithmic stages (each of which make up a stage in a pipeline). We formulate the problem of mapping each algorithmic stage in the system to an ASIP configuration, and propose a heuristic to efficiently search the design space for a pipeline-based multi ASIP system.We have implemented the proposed heterogeneous multiprocessor methodology using a commercial extensible processor (Xtensa LX from Tensilica Inc.). We have evaluated our system by creating two benchmarks (MP3 and JPEG encoders) which are mapped to our proposed design platform. Our multiprocessor design provided a performance improvement of at least 4.11X (JPEG) and 3.36X (MP3) compared to the single processor design. The minimum cost obtained through our heuristic was within 5.47% and 5.74% of the best possible values for JPEG and MP3 benchmarks respectively.

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Abstract

Multiprocessor SoCs are increasingly deployed in embedded systems with little or no security features built in. Code Injection attacks are one of the most commonly encountered security threats. Most solutions to this problem in the single processor domain are purely software based and have high overheads. A few hardware solutions have been provided for the single processor case, which significantly reduce overheads. In this paper, for the first time, we propose a methodology addressing code injection attacks in a multiprocessor domain. A dedicated security (monitor) processor is used to oversee the application at runtime. Each processor communicates with the monitor processor through a FIFO queue, and is continuously checked.Static analysis of program map and timing profile are used to obtain program information at compile time, which is utilized by the monitor processor at runtime. This information is encrypted using a secure key and stored in the monitor processor. A copy of this secure key is built into the processor's hardware and is used for decryption by the monitor processor. Each basic block of the program is also instrumented with security information that uniquely identifies itself at runtime. The information from static analysis thus allows the monitor processor to supervise the proceedings on each processor at runtime.Our approach uses a combination of hardware and software techniques to keep overheads to a minimum. We implemented our methodology on a commercial extensible processor (Xtensa LX). Our approach successfully detects the execution of injected code when tested on a JPEG multiprocessor benchmark. The results show a small increase of 6.6% in application processors' runtime (clock cycle count) and 35.2% in code size for the JPEG encoder benchmark.