On Wed, Jul 23, 2014 at 9:43 PM, Andrew Fish <afish@apple.com> wrote:
> What form do get for _PCD_GET_MODE_*_PcdFvBaseAddress in the AutoGen.h? That
> is the real issue.

>
> https://svn.code.sf.net/p/edk2/code/trunk/edk2/MdePkg/Include/Library/PcdLib.h
>
> #define PcdGet8(TokenName)                  _PCD_GET_MODE_8_##TokenName
>
> The behavior of libraries (try to inherit things from drivers) and drivers
> is different. Where is the PCD in question?

I see that `PeiUniCore/DEBUG/AutoGen.h` contains
`#define _PCD_GET_MODE_32_PcdFvBaseAddress  _gPcd_FixedAtBuild_PcdFvBaseAddress`

and `PeiUniCore/DEBUG/AutoGen.c`:
`GLOBAL_REMOVE_IF_UNREFERENCED const UINT32 _gPcd_FixedAtBuild_PcdFvBaseAddress = _PCD_VALUE_PcdFvBaseAddress;`

also, in PeiUniCore/DEBUG/AutoGen.h
`#define _PCD_VALUE_PcdFvBaseAddress  0x80008000U`

So _PCD_GET_MODE_32_PcdFvBaseAddress should get set to the right value.


On Jul 23, 2014, at 5:36 AM, Laszlo Ersek <lersek@redhat.com> wrote:
> (I cannot condemn RELEASE builds
> enough.) Namely, you call
>
>    UINT32
>    EFIAPI
>    LibPcdGet32 (
>      IN UINTN             TokenNumber
>      )
>    {
>      ASSERT (FALSE);
>
>      return 0;
>    }
>
> from "MdePkg/Library/BasePcdLibNull/PcdLib.c", and since you build for
> RELEASE, the ASSERT() is a no-op. In a DEBUG build you'd have caught
> this immediately with a failed assertion: the Null implementation of
> PcdLib doesn't allow you to actually access PCDs.

Oddly, the call to PcdGet32() from PrePi doesn't get here. It takes the MdePkg/Include/Library/PcdLib.h:

#define PcdGet32(TokenName)                 _PCD_GET_MODE_32_##TokenName

route instead.

> Library instances that usably resolve the PcdLib library class are:
>
> $ git grep -l 'LIBRARY_CLASS *= *PcdLib' -- '*.inf'
>
> EmulatorPkg/Library/SmbiosLib/SmbiosLib.inf
> MdePkg/Library/BasePcdLibNull/BasePcdLibNull.inf
> MdePkg/Library/DxePcdLib/DxePcdLib.inf
> MdePkg/Library/PeiPcdLib/PeiPcdLib.inf
>
> In PEIMs, you need the fourth; in DXE & UEFI drivers, you need the third.
>
> However, this is not the entire picture yet, because these libraries
> delegate the work to a PPI (in PEI) and to a protocol (in DXE) that are
> provided by dedicated drivers, respectively:
> - MdeModulePkg/Universal/PCD/Pei/Pcd.inf
> - MdeModulePkg/Universal/PCD/Dxe/Pcd.inf
>
> You should add these drivers to the corresponding (ie. PEI vs. DXE)
> APRIORI files of the firmware volumes that your FDF file defines, so
> that any driver loaded / dispatched later can use their PCD services
> (through the above-mentioned library instances). Refer to
> OvmfPkg/OvmfPkgX64.fdf for examples.

Thanks, I was unaware of that.

Varad