A guided debugger-based fault injection methodology for assessing functional test programs

Functional test programs are increasingly used as flexible approaches to verify device functionality, both online (e.g., Software-Based Self Tests encapsulated in Software Test Library) and during the manufacturing test flow (e.g., System-Level Test). However, a traditional integrated development environment seldom analyzes functional test program weaknesses regarding fault-masking and propagation in CPU registers. Therefore, understanding the presence of errors in the programs due to logic faults at the end of the test program is only assessed by a signature computation, e.g., xor operation between all registers. The presence of program weaknesses in terms of data or control flow is not assessed, and it may lead to fault escapes and/or masking. In particular, those are perfect conditions for proliferating Silent data corruption and unrecoverable errors at the system level.This work aims to introduce a guided debugger-based fault injector framework to verify the fault propagation and masking capabilities of functional test programs by eventually catching program errors without relying on time-consuming simulation-based approaches. The fault-free instruction trace is dumped and analyzed to provide information about possible target registers of specific instructions for injecting faults, e.g., in jump instructions, where errors into registers may change the execution flow or not, to verify the presence of silent data corruptions and errors.The experimental results are carried out on an automotive device from the SPC58 family manufactured by STMicroelectronics, and faults are injected through a script running on Power Debug E40 from Lauterbach.