A low-cost, radiation-hardened method for pipeline protection in microprocessors

The aggressive scaling of semiconductor technology has significantly increased the radiation-induced soft error rate in modern microprocessors. Meanwhile, due to the increasing complexity of modern processor pipelines and the limited error-tolerance capabilities that previous radiation hardening techniques can provide, the existing pipeline protection mechanisms cannot achieve complete protection. This paper proposes a complete and cost-effective pipeline protection mechanism using a self-checking architecture. The radiation hardened pipeline is achieved by incorporating SETTOFF-based self-checking cells into the sequential cells of the pipeline. A replay recovery mechanism is also developed at the architectural level to recover the detected errors. The proposed pipeline protection technique is implemented in an OpenRISC microprocessor in 65nm technology. A gate-level transient fault injection and analysis technique is used to evaluate the error-tolerance capability of the proposed hardened pipeline design. The results show that compared to techniques such as TMR, the SETTOFF-based self-checking technique requires over 30% less area and 80% less power overheads. Meanwhile, the error-tolerant and self-checking capabilities of the register allow the proposed pipeline protection technique to provide a noticeably higher level of reliability for different parts of the pipeline compared to previous pipeline protection techniques