Category: Arium Probes | SourcePoint™

JTAG can be used to explore the behavior of interrupt dispatching internals in a new way. This article describes the functionality of the Interrupt Descriptor Table (IDT) as an Intel target is booted from the reset vector, through UEFI, and into Windows.
While doing some low-level debugging using SourcePoint, I noticed some interesting and puzzling behavior of Intel E-cores (based upon Atom architecture) versus P-cores (based on Core architecture).
In my prior two articles, I demonstrated the use of JTAG to set breakpoints inside SMM that survive Entry and Exit, and how to use Last Branch Record (LBR) trace to do dynamic analysis. In this blog, I show how to set up a visual view of SMRAM that updates dynamically as SMIs are hit.
This article describes using JTAG in combination with Intel Trace features, specifically Last Branch Record (LBR) trace, to research the internals of System Management Mode (SMM).
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