ArmVirtPkg: Convert ArmVirtGicArchLib to NULL class library

Before retiring ArmGicArchLib entirely, convert the existing
implementation in ArmVirtPkg into a NULL class library and inject it
into ArmGicDxe on all ARM virtual platforms. This ensures that the PCDs
describing the GIC are intialized correctly before ArmGicDxe is
dispatched.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

ArmVirtPkg/ArmVirt.dsc.inc

@@ -105,7 +105,6 @@
   CpuExceptionHandlerLib|ArmPkg/Library/ArmExceptionLib/ArmExceptionLib.inf
   ArmDisassemblerLib|ArmPkg/Library/ArmDisassemblerLib/ArmDisassemblerLib.inf
   ArmGicLib|ArmPkg/Drivers/ArmGic/ArmGicLib.inf
-  ArmGicArchLib|ArmVirtPkg/Library/ArmVirtGicArchLib/ArmVirtGicArchLib.inf
   ArmSmcLib|ArmPkg/Library/ArmSmcLib/ArmSmcLib.inf
   ArmHvcLib|ArmPkg/Library/ArmHvcLib/ArmHvcLib.inf
   ArmGenericTimerCounterLib|ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.inf

ArmVirtPkg/ArmVirtCloudHv.dsc

@@ -279,7 +279,10 @@
 
   MdeModulePkg/Universal/HiiDatabaseDxe/HiiDatabaseDxe.inf
 
-  ArmPkg/Drivers/ArmGic/ArmGicDxe.inf
+  ArmPkg/Drivers/ArmGic/ArmGicDxe.inf {
+    <LibraryClasses>
+      NULL|ArmVirtPkg/Library/ArmVirtGicArchLib/ArmVirtGicArchLib.inf
+  }
   ArmPkg/Drivers/TimerDxe/TimerDxe.inf {
     <LibraryClasses>
       NULL|ArmVirtPkg/Library/ArmVirtTimerFdtClientLib/ArmVirtTimerFdtClientLib.inf

ArmVirtPkg/ArmVirtKvmTool.dsc

@@ -299,7 +299,10 @@
 
   MdeModulePkg/Universal/HiiDatabaseDxe/HiiDatabaseDxe.inf
 
-  ArmPkg/Drivers/ArmGic/ArmGicDxe.inf
+  ArmPkg/Drivers/ArmGic/ArmGicDxe.inf {
+    <LibraryClasses>
+      NULL|ArmVirtPkg/Library/ArmVirtGicArchLib/ArmVirtGicArchLib.inf
+  }
   ArmPkg/Drivers/TimerDxe/TimerDxe.inf {
     <LibraryClasses>
       NULL|ArmVirtPkg/Library/ArmVirtTimerFdtClientLib/ArmVirtTimerFdtClientLib.inf

ArmVirtPkg/ArmVirtQemu.dsc

@@ -428,7 +428,10 @@
 
   MdeModulePkg/Universal/HiiDatabaseDxe/HiiDatabaseDxe.inf
 
-  ArmPkg/Drivers/ArmGic/ArmGicDxe.inf
+  ArmPkg/Drivers/ArmGic/ArmGicDxe.inf {
+    <LibraryClasses>
+      NULL|ArmVirtPkg/Library/ArmVirtGicArchLib/ArmVirtGicArchLib.inf
+  }
   ArmPkg/Drivers/TimerDxe/TimerDxe.inf {
     <LibraryClasses>
       NULL|ArmVirtPkg/Library/ArmVirtTimerFdtClientLib/ArmVirtTimerFdtClientLib.inf

ArmVirtPkg/ArmVirtQemuKernel.dsc

@@ -338,7 +338,10 @@
 
   MdeModulePkg/Universal/HiiDatabaseDxe/HiiDatabaseDxe.inf
 
-  ArmPkg/Drivers/ArmGic/ArmGicDxe.inf
+  ArmPkg/Drivers/ArmGic/ArmGicDxe.inf {
+    <LibraryClasses>
+      NULL|ArmVirtPkg/Library/ArmVirtGicArchLib/ArmVirtGicArchLib.inf
+  }
   ArmPkg/Drivers/TimerDxe/TimerDxe.inf {
     <LibraryClasses>
       NULL|ArmVirtPkg/Library/ArmVirtTimerFdtClientLib/ArmVirtTimerFdtClientLib.inf

ArmVirtPkg/ArmVirtXen.dsc

@@ -192,7 +192,10 @@
 
   MdeModulePkg/Universal/HiiDatabaseDxe/HiiDatabaseDxe.inf
 
-  ArmPkg/Drivers/ArmGic/ArmGicDxe.inf
+  ArmPkg/Drivers/ArmGic/ArmGicDxe.inf {
+    <LibraryClasses>
+      NULL|ArmVirtPkg/Library/ArmVirtGicArchLib/ArmVirtGicArchLib.inf
+  }
   ArmPkg/Drivers/TimerDxe/TimerDxe.inf {
     <LibraryClasses>
       NULL|ArmVirtPkg/Library/ArmVirtTimerFdtClientLib/ArmVirtTimerFdtClientLib.inf

ArmVirtPkg/Library/ArmVirtGicArchLib/ArmVirtGicArchLib.c

@@ -1,5 +1,5 @@
 /** @file
-  ArmGicArchLib library class implementation for DT based virt platforms
+  NULL library class implementation to discover the GIC for DT based virt platforms
 
   Copyright (c) 2015 - 2016, Linaro Ltd. All rights reserved.<BR>
 
@@ -11,7 +11,6 @@
 #include <Uefi.h>
 
 #include <Library/ArmGicLib.h>
-#include <Library/ArmGicArchLib.h>
 #include <Library/BaseLib.h>
 #include <Library/DebugLib.h>
 #include <Library/PcdLib.h>
@@ -19,15 +18,12 @@
 
 #include <Protocol/FdtClient.h>
 
-STATIC ARM_GIC_ARCH_REVISION  mGicArchRevision;
-
 RETURN_STATUS
 EFIAPI
 ArmVirtGicArchLibConstructor (
   VOID
   )
 {
-  UINT32               IccSre;
   FDT_CLIENT_PROTOCOL  *FdtClient;
   CONST UINT64         *Reg;
   UINT32               RegSize;
@@ -105,25 +101,6 @@ ArmVirtGicArchLibConstructor (
         RedistBase
         ));
 
-      //
-      // The default implementation of ArmGicArchLib is responsible for enabling
-      // the system register interface on the GICv3 if one is found. So let's do
-      // the same here.
-      //
-      IccSre = ArmGicV3GetControlSystemRegisterEnable ();
-      if (!(IccSre & ICC_SRE_EL2_SRE)) {
-        ArmGicV3SetControlSystemRegisterEnable (IccSre | ICC_SRE_EL2_SRE);
-        IccSre = ArmGicV3GetControlSystemRegisterEnable ();
-      }
-
-      //
-      // Unlike the default implementation, there is no fall through to GICv2
-      // mode if this GICv3 cannot be driven in native mode due to the fact
-      // that the System Register interface is unavailable.
-      //
-      ASSERT (IccSre & ICC_SRE_EL2_SRE);
-
-      mGicArchRevision = ARM_GIC_ARCH_REVISION_3;
       break;
 
     case 2:
@@ -146,7 +123,6 @@ ArmVirtGicArchLibConstructor (
 
       DEBUG ((DEBUG_INFO, "Found GIC @ 0x%Lx/0x%Lx\n", DistBase, CpuBase));
 
-      mGicArchRevision = ARM_GIC_ARCH_REVISION_2;
       break;
 
     default:
@@ -156,12 +132,3 @@ ArmVirtGicArchLibConstructor (
 
   return RETURN_SUCCESS;
 }
-
-ARM_GIC_ARCH_REVISION
-EFIAPI
-ArmGicGetSupportedArchRevision (
-  VOID
-  )
-{
-  return mGicArchRevision;
-}

ArmVirtPkg/Library/ArmVirtGicArchLib/ArmVirtGicArchLib.inf

@@ -14,7 +14,7 @@
   FILE_GUID                      = 87b0dc84-4661-4deb-a789-97977ff636ed
   MODULE_TYPE                    = BASE
   VERSION_STRING                 = 1.0
-  LIBRARY_CLASS                  = ArmGicArchLib|DXE_DRIVER UEFI_DRIVER UEFI_APPLICATION
+  LIBRARY_CLASS                  = NULL|DXE_DRIVER UEFI_DRIVER UEFI_APPLICATION
   CONSTRUCTOR                    = ArmVirtGicArchLibConstructor
 
 [Sources]