[PATCH 3/3] MdeModulePkg/AcpiTableDxe: use pool allocation for RSDP if possible

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

Use a pool allocation for the RSDP ACPI root pointer structure if no
memory limit is in effect that forces us to use page based allocation,
which may be wasteful if they get rounded up to 64 KB as is the case
on AArch64.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
---
 MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiTableProtocol.c | 30 ++++++++++++++------
 1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiTableProtocol.c b/MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiTableProtocol.c
index 22f49a8489e7..fb939aa00f49 100644
--- a/MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiTableProtocol.c
+++ b/MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiTableProtocol.c
@@ -1737,19 +1737,26 @@ AcpiTableAcpiTableConstructor (
     RsdpTableSize += sizeof (EFI_ACPI_1_0_ROOT_SYSTEM_DESCRIPTION_POINTER);
   }
 
-  PageAddress = 0xFFFFFFFF;
-  Status = gBS->AllocatePages (
-                  mAcpiTableAllocType,
-                  EfiACPIReclaimMemory,
-                  EFI_SIZE_TO_PAGES (RsdpTableSize),
-                  &PageAddress
-                  );
+  if (mAcpiTableAllocType != AllocateAnyPages) {
+    PageAddress = 0xFFFFFFFF;
+    Status = gBS->AllocatePages (
+                    mAcpiTableAllocType,
+                    EfiACPIReclaimMemory,
+                    EFI_SIZE_TO_PAGES (RsdpTableSize),
+                    &PageAddress
+                    );
+    Pointer = (UINT8 *)(UINTN)PageAddress;
+  } else {
+    Status = gBS->AllocatePool (
+                    EfiACPIReclaimMemory,
+                    RsdpTableSize,
+                    (VOID **)&Pointer);
+  }
 
   if (EFI_ERROR (Status)) {
     return EFI_OUT_OF_RESOURCES;
   }
 
-  Pointer = (UINT8 *) (UINTN) PageAddress;
   ZeroMem (Pointer, RsdpTableSize);
 
   AcpiTableInstance->Rsdp1 = (EFI_ACPI_1_0_ROOT_SYSTEM_DESCRIPTION_POINTER *) Pointer;
@@ -1797,7 +1804,12 @@ AcpiTableAcpiTableConstructor (
   }
 
   if (EFI_ERROR (Status)) {
-    gBS->FreePages ((EFI_PHYSICAL_ADDRESS)(UINTN)AcpiTableInstance->Rsdp1, EFI_SIZE_TO_PAGES (RsdpTableSize));
+    if (mAcpiTableAllocType != AllocateAnyPages) {
+      gBS->FreePages ((EFI_PHYSICAL_ADDRESS)(UINTN)AcpiTableInstance->Rsdp1,
+             EFI_SIZE_TO_PAGES (RsdpTableSize));
+    } else {
+      gBS->FreePool (AcpiTableInstance->Rsdp1);
+    }
     return EFI_OUT_OF_RESOURCES;
   }
 
-- 
2.17.1