APRIORI declarations are evil. They force a driver to be dispatched before any other drivers, while completely ignoring normal precedence rules or protocol dependencies.
In this particular case, the DXE version of Pcd.inf is loaded a priori to work around the problem that the default PcdLib resolution introduces a a protocol dependency on gPcdProtocolGuid, which provides dynamic PCD handling for other drivers, and is implemented by Pcd.inf. Since Pcd.inf depends on PcdLib as well, it can never be dispatched in the ordinary way if it inherits the default PcdLib resolution (since that will make it depend on itself), and so it must be made to depend on the Null implementation of PcdLib explicitly.
So add this explicit override, and drop the A PRIORI declarations.
Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Ard Biesheuvel ard.biesheuvel@linaro.org ---
Note that the same reasoning applies to the PEI version of Pcd.inf, but we don't normally use that, and in fact, it already has a similar Null library class override in ArmVExpress-FVP-AArch64.dsc
Platforms/ARM/Juno/ArmJuno.fdf | 4 ---- Platforms/ARM/VExpress/ArmVExpress-FVP-AArch64.fdf | 4 ---- Platforms/ARM/VExpress/ArmVExpress.dsc.inc | 5 ++++- 3 files changed, 4 insertions(+), 9 deletions(-)
diff --git a/Platforms/ARM/Juno/ArmJuno.fdf b/Platforms/ARM/Juno/ArmJuno.fdf index a05151086910..3983c20de8e0 100644 --- a/Platforms/ARM/Juno/ArmJuno.fdf +++ b/Platforms/ARM/Juno/ArmJuno.fdf @@ -86,10 +86,6 @@ READ_LOCK_CAP = TRUE READ_LOCK_STATUS = TRUE FvNameGuid = B73FE497-B92E-416e-8326-45AD0D270092
- APRIORI DXE { - INF MdeModulePkg/Universal/PCD/Dxe/Pcd.inf - } - INF MdeModulePkg/Core/Dxe/DxeMain.inf INF MdeModulePkg/Universal/PCD/Dxe/Pcd.inf
diff --git a/Platforms/ARM/VExpress/ArmVExpress-FVP-AArch64.fdf b/Platforms/ARM/VExpress/ArmVExpress-FVP-AArch64.fdf index 79c074c834d8..3bcdb1ca43f1 100644 --- a/Platforms/ARM/VExpress/ArmVExpress-FVP-AArch64.fdf +++ b/Platforms/ARM/VExpress/ArmVExpress-FVP-AArch64.fdf @@ -73,10 +73,6 @@ READ_LOCK_CAP = TRUE READ_LOCK_STATUS = TRUE FvNameGuid = 87940482-fc81-41c3-87e6-399cf85ac8a0
- APRIORI DXE { - INF MdeModulePkg/Universal/PCD/Dxe/Pcd.inf - } - INF MdeModulePkg/Core/Dxe/DxeMain.inf INF MdeModulePkg/Universal/PCD/Dxe/Pcd.inf
diff --git a/Platforms/ARM/VExpress/ArmVExpress.dsc.inc b/Platforms/ARM/VExpress/ArmVExpress.dsc.inc index 9bb45c82a5e9..d898aef490f9 100644 --- a/Platforms/ARM/VExpress/ArmVExpress.dsc.inc +++ b/Platforms/ARM/VExpress/ArmVExpress.dsc.inc @@ -443,7 +443,10 @@ !endif
[Components.common] - MdeModulePkg/Universal/PCD/Dxe/Pcd.inf + MdeModulePkg/Universal/PCD/Dxe/Pcd.inf { + <LibraryClasses> + PcdLib|MdePkg/Library/BasePcdLibNull/BasePcdLibNull.inf + }
# Versatile Express FileSystem ArmPlatformPkg/FileSystem/BootMonFs/BootMonFs.inf
On 19 April 2016 at 08:49, Ard Biesheuvel ard.biesheuvel@linaro.org wrote:
APRIORI declarations are evil. They force a driver to be dispatched before any other drivers, while completely ignoring normal precedence rules or protocol dependencies.
In this particular case, the DXE version of Pcd.inf is loaded a priori to work around the problem that the default PcdLib resolution introduces a a protocol dependency on gPcdProtocolGuid, which provides dynamic PCD handling for other drivers, and is implemented by Pcd.inf. Since Pcd.inf depends on PcdLib as well, it can never be dispatched in the ordinary way if it inherits the default PcdLib resolution (since that will make it depend on itself), and so it must be made to depend on the Null implementation of PcdLib explicitly.
So add this explicit override, and drop the A PRIORI declarations.
Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Ard Biesheuvel ard.biesheuvel@linaro.org
Tested-by: Ryan Harkin ryan.harkin@linaro.org
Tested on Juno R0, R1 and R2, FVP Base AEMv8 and FVP Foundation models.
Note that the same reasoning applies to the PEI version of Pcd.inf, but we don't normally use that, and in fact, it already has a similar Null library class override in ArmVExpress-FVP-AArch64.dsc
Platforms/ARM/Juno/ArmJuno.fdf | 4 ---- Platforms/ARM/VExpress/ArmVExpress-FVP-AArch64.fdf | 4 ---- Platforms/ARM/VExpress/ArmVExpress.dsc.inc | 5 ++++- 3 files changed, 4 insertions(+), 9 deletions(-)
diff --git a/Platforms/ARM/Juno/ArmJuno.fdf b/Platforms/ARM/Juno/ArmJuno.fdf index a05151086910..3983c20de8e0 100644 --- a/Platforms/ARM/Juno/ArmJuno.fdf +++ b/Platforms/ARM/Juno/ArmJuno.fdf @@ -86,10 +86,6 @@ READ_LOCK_CAP = TRUE READ_LOCK_STATUS = TRUE FvNameGuid = B73FE497-B92E-416e-8326-45AD0D270092
- APRIORI DXE {
- INF MdeModulePkg/Universal/PCD/Dxe/Pcd.inf
- }
- INF MdeModulePkg/Core/Dxe/DxeMain.inf INF MdeModulePkg/Universal/PCD/Dxe/Pcd.inf
diff --git a/Platforms/ARM/VExpress/ArmVExpress-FVP-AArch64.fdf b/Platforms/ARM/VExpress/ArmVExpress-FVP-AArch64.fdf index 79c074c834d8..3bcdb1ca43f1 100644 --- a/Platforms/ARM/VExpress/ArmVExpress-FVP-AArch64.fdf +++ b/Platforms/ARM/VExpress/ArmVExpress-FVP-AArch64.fdf @@ -73,10 +73,6 @@ READ_LOCK_CAP = TRUE READ_LOCK_STATUS = TRUE FvNameGuid = 87940482-fc81-41c3-87e6-399cf85ac8a0
- APRIORI DXE {
- INF MdeModulePkg/Universal/PCD/Dxe/Pcd.inf
- }
- INF MdeModulePkg/Core/Dxe/DxeMain.inf INF MdeModulePkg/Universal/PCD/Dxe/Pcd.inf
diff --git a/Platforms/ARM/VExpress/ArmVExpress.dsc.inc b/Platforms/ARM/VExpress/ArmVExpress.dsc.inc index 9bb45c82a5e9..d898aef490f9 100644 --- a/Platforms/ARM/VExpress/ArmVExpress.dsc.inc +++ b/Platforms/ARM/VExpress/ArmVExpress.dsc.inc @@ -443,7 +443,10 @@ !endif
[Components.common]
- MdeModulePkg/Universal/PCD/Dxe/Pcd.inf
MdeModulePkg/Universal/PCD/Dxe/Pcd.inf {
<LibraryClasses>
PcdLib|MdePkg/Library/BasePcdLibNull/BasePcdLibNull.inf}
# Versatile Express FileSystem ArmPlatformPkg/FileSystem/BootMonFs/BootMonFs.inf
-- 2.5.0
-
Ard Biesheuvel -
Ryan Harkin