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

A control-flow checking method is proposed. Extended-precision checksum-based control-flow checking 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. 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 is defined. Unlike previously proposed control-flow checking methods, this watchdog assist architecture is well suited for multiprocessor, multiprogramming, and cache-based environments. The Hewlett-Packard precision architecture is used as an example to demonstrate the feasibility of watchdog assists.<>