[PATCH v2 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 | 33 ++++++++++++++------
 1 file changed, 24 insertions(+), 9 deletions(-)

diff --git a/MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiTableProtocol.c b/MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiTableProtocol.c
index 3793291a9668..edd7f9afd4fc 100644
--- a/MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiTableProtocol.c
+++ b/MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiTableProtocol.c
@@ -1745,19 +1745,29 @@ 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
+                    );
+  } else {
+    Status = gBS->AllocatePool (
+                    EfiACPIReclaimMemory,
+                    RsdpTableSize,
+                    (VOID **)&Pointer
+                    );
+  }
 
   if (EFI_ERROR (Status)) {
     return EFI_OUT_OF_RESOURCES;
   }
 
-  Pointer = (UINT8 *) (UINTN) PageAddress;
+  if (mAcpiTableAllocType != AllocateAnyPages) {
+    Pointer = (UINT8 *)(UINTN)PageAddress;
+  }
   ZeroMem (Pointer, RsdpTableSize);
 
   AcpiTableInstance->Rsdp1 = (EFI_ACPI_1_0_ROOT_SYSTEM_DESCRIPTION_POINTER *) Pointer;
@@ -1805,7 +1815,12 @@ 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