A Flexible Software-Based Framework for Online Detection of Hardware Defects

[aruljothi]

Abstract

As silicon process technology scales deeper into the nanometer regime, hardware defects are becoming more common. Such defects are bound to hinder the correct operation of future processor systems, unless new online techniques become available to detect and tolerate them while preserving the integrity of software applications running on the system. This work proposes a new, software-based, defect detection and diagnosis technique. We introduce a novel set of instructions, called Access-Control Extensions (ACE), that can access and control the microprocessor's internal state. Special firmware periodically suspends microprocessor execution and uses the ACE instructions to run directed tests on the hardware. When a hardware defect is present, these tests can diagnose and locate it, and then activate system repair through resource reconfiguration. The software nature of our framework makes it flexible: testing techniques can be modified/upgraded in the field to trade off performance with reliability without requiring any change to the hardware. We describe and evaluate different execution models for using the ACE framework. We also describe how the proposed ACE framework can be extended and utilized to improve the quality of post-silicon debugging and manufacturing testing of modern processors.