Hierarchical Checking of Multiprocessors Using Watchdog Processors

A new control flow checking scheme, based on assigned-signature checking by a watchdog processor, is presented. This scheme is suitable for a multitasking, multiprocessor environment. The hardware overhead is comparatively low because of three reasons: first, hierarchically structured, the scheme uses only a single watchdog processor to monitor multiple processes or processors. Second, as an assigned-signature scheme it does not require monitoring the instruction bus of the processors. Third, the run-time and reference signatures are embedded into the checked program; thus, in the watchdog processor neither a reference database nor a time-consuming search and compare engine is required.