Category: Software Debug and Trace

UEFI, like other embedded code bases, is riddled with printf style debug statements. In debug builds, these can slow the boot process down tremendously. There is a way to circumvent this.
Intel Processor Trace (Intel PT) is a capability on new Intel silicon that captures information about software execution using dedicated hardware facilities inside the chip. How is it used to debug UEFI?
Conventional printf statements within a BIOS being debugged add a lot of โ€œbackpressureโ€ due to the overhead within the printf routine and the cost of directing the output through a slow serial port. This slows the debugging process down, and may even mask some time-sensitive bugs. Is there a better, more non-intrusive way?
As the UEFI Forum continues to make advances in the technology behind what is still called the BIOS (Basic Input/Output System), ASSET has joined this standards body to assist in the debug of its latest features.
If you are a beginning BIOS engineer, manage BIOS engineers, or even an expert who just needs a refresher, these great UEFI videos from Intel are worthwhile watching.
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