PI 1.3 Review, Part 3: Updates to FindSectionData PEI Services

This article is the third in a series describing the changes made in the PI 1.3 specification. This time we look at a new entry added to the PEI Services table: FindSectionData3(). There's only one problem: this function doesn't actually show up in the table of contents, even though it is listed in the PEI Services Table in section 3.2.1 of Volume 1 of the PI.

So what happened? Well, it turns out that this function is an update to another PEI Service: FindSectionData() and simply adds a new parameter: AuthenticationStatus. This returns the result of authentication for a specific single section. The PEI core has access to this information, when it calls the Security Architecture PPI, but never passed it back. This meant that some callers, such as implementations of the Load File PPI, would have to either call the Security Architecture PPI themselves (adding delay and complexity) or hard-code it to 0 (which is what the tianocore implementation was doing). This new PEI Service optionally returns this and does so in a way that the previous function (FindSectionData()) could be implemented by calling the new function, just setting AuthenticationStatus to NULL.

But when the new function was added to the specification, there was an editing error. The new function parameter was added to FindSectionData(), which was the existing function and the new function (FindSectionData3()) is nowhere to be found. I expect this will be fixed in an errata.

Now PI 1.3 has the ability to parse firmware volumes in a secure (!) and fast (!) manner.