Re: [edk2-devel] APRIORI in RISC-V or Where did OVMF APRIORIs come from?

["Ard Biesheuvel" <ard.biesheuvel@arm.com>]

On 5/7/20 3:18 PM, Daniel Schaefer via groups.io wrote:
> Hi Ard and others,
> 
> TLDR; We have APRIORI definitions from other places in EDK2 but there's 
> no explanation as to why they are there.
> 
> I'm taking this to the EDK2 list, since it doesn't concern U-Boot.
> I kept some other people related to UEFI, maybe you're interested ;)
> 
> On 2/25/20 10:07 AM, Ard Biesheuvel wrote:
>  > What I did notice is the use of APRIORI PEI and APRIORI DXE sections
>  > in your platform descriptions. I recommend you try to avoid that, as
>  > it is a maintenance burden going forward: instead, please use dummy
>  > protocols and NULL library class resolutions if you need to make
>  > generic components depend on platform specific protocols. Also, please
>  > document this - the APRIORI section does not explain *why* you have to
>  > circumvent the ordinary dependency tree based module dispatch.
> 
> I'm taking a look at this right now.
> You're absolutely right - we should reduce or document APRIORIs.
> 
> However, Abner told me that he had only copied most of the FDF from other
> places in EDK2.This is what we currently have:
> 
> APRIORI PEI {
>    INF 
> MdeModulePkg/Universal/ReportStatusCodeRouter/Pei/ReportStatusCodeRouterPei.inf 
> 
>    INF 
> MdeModulePkg/Universal/StatusCodeHandler/Pei/StatusCodeHandlerPei.inf
>    INF  MdeModulePkg/Universal/PCD/Pei/Pcd.inf
> }
> APRIORI DXE {
>    INF MdeModulePkg/Universal/DevicePathDxe/DevicePathDxe.inf
>    INF  MdeModulePkg/Universal/PCD/Dxe/Pcd.inf
>    INF 
> Platform/SiFive/U5SeriesPkg/Universal/Dxe/RamFvbServicesRuntimeDxe/FvbServicesRuntimeDxe.inf 
> 
> }
> 
> I can remove all of APRIORI PEI and it boots properly. Of the DXEs I can 
> only
> remove FvbServicesRuntimeDxe, otherwise some DXEs are dispatched in the 
> wrong
> order and boot fails.

This means some modules have an undeclared dependency on one of the 
remaining modules. Can you elaborate on how the boot fails in this case?