[Fw_Os_Forum] Support for EFI MP Services

Brett Stahlman brettstahlman at gmail.com
Fri Jul 15 12:11:22 EDT 2016

I'm working on an x86_64 UEFI boot loader that runs on the BSP in
64-bit long mode, and must bring up APs (secondary processors) after
some preliminary initialization. I've seen some documentation on EFI
MP (multi-processor) Service Protocol, but the headers in gnu-efi
don't appear to support it, and BS->LocateProtocol() reports status 14
(EFI_NOT_FOUND). My questions are...

1. Is there a way to add support for MP Services to firmware that
doesn't have it natively? Is there a list somewhere documenting which
firmware supports?
2. What is the best way to bring up the APs in an environment that
doesn't support the MP Services Protocol? I've read something that
suggests it might be easier with UEFI than with BIOS because the PI
firmware does some pre-initialization of the APs even before handoff
to the BSP - but I haven't found much documentation on this...

Any help would be greatly appreciated.
Brett S.

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