Control-flow checking using watchdog assists and extended-precision checksums

A control-flow checking method using extended-precision checksums and watchdog assists is proposed. Control-flow checking based on extended-precision checksums is shown to have low error detection latency compared to previously proposed methods. Analytical measures are derived to demonstrate the effectiveness of using extended-precision checksums for control flow checking. It is shown that the error detection latency in the extended-precision-checksum-based control-flow checking remains relatively constant for both single and multiple sequence errors. In the case of signature-based methods, error detection latency increases linearly with the number of sequence errors. A watchdog assist architecture for control-flow checking in programs which addresses several architecture issues is proposed. This watchdog assist architecture can support control-flow checking for multiprocessor, multiprogramming, and cache-based environments. The Hewlett-Packard Precision Architecture is used as an example architecture to demonstrate the feasibility of watchdog assists