[PATCH v4 4/4] MdeModulePkg/PeiCore: honour minimal runtime allocation granularity

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

Architectures such as AArch64 may run the OS with 16 KB or 64 KB sized
pages, and for this reason, the UEFI spec mandates a minimal allocation
granularity of 64 KB for regions that may require different memory
attributes at OS runtime.

So make PeiCore's implementation of AllocatePages () take this into
account as well.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Star Zeng <star.zeng@intel.com>
---
 MdeModulePkg/Core/Pei/Memory/MemoryServices.c | 39 +++++++++++++++++++-
 1 file changed, 37 insertions(+), 2 deletions(-)

diff --git a/MdeModulePkg/Core/Pei/Memory/MemoryServices.c b/MdeModulePkg/Core/Pei/Memory/MemoryServices.c
index 4efe14313ca5..719372e06128 100644
--- a/MdeModulePkg/Core/Pei/Memory/MemoryServices.c
+++ b/MdeModulePkg/Core/Pei/Memory/MemoryServices.c
@@ -140,6 +140,8 @@ PeiAllocatePages (
   EFI_PHYSICAL_ADDRESS                    *FreeMemoryTop;
   EFI_PHYSICAL_ADDRESS                    *FreeMemoryBottom;
   UINTN                                   RemainingPages;
+  UINTN                                   Granularity;
+  UINTN                                   Padding;
 
   if ((MemoryType != EfiLoaderCode) &&
       (MemoryType != EfiLoaderData) &&
@@ -153,6 +155,20 @@ PeiAllocatePages (
     return EFI_INVALID_PARAMETER;
   }
 
+  Granularity = DEFAULT_PAGE_ALLOCATION_GRANULARITY;
+
+  if  (RUNTIME_PAGE_ALLOCATION_GRANULARITY > DEFAULT_PAGE_ALLOCATION_GRANULARITY &&
+       (MemoryType == EfiACPIReclaimMemory   ||
+        MemoryType == EfiACPIMemoryNVS       ||
+        MemoryType == EfiRuntimeServicesCode ||
+        MemoryType == EfiRuntimeServicesData)) {
+
+    Granularity = RUNTIME_PAGE_ALLOCATION_GRANULARITY;
+
+    DEBUG ((DEBUG_INFO, "AllocatePages: aligning allocation to %d KB\n",
+      Granularity / SIZE_1KB));
+  }
+
   PrivateData = PEI_CORE_INSTANCE_FROM_PS_THIS (PeiServices);
   Hob.Raw     = PrivateData->HobList.Raw;
   
@@ -176,9 +192,27 @@ PeiAllocatePages (
   }
 
   //
-  // Check to see if on 4k boundary, If not aligned, make the allocation aligned.
+  // Check to see if on correct boundary for the memory type.
+  // If not aligned, make the allocation aligned.
   //
-  *(FreeMemoryTop) -= *(FreeMemoryTop) & 0xFFF;
+  Padding = *(FreeMemoryTop) & (Granularity - 1);
+  if ((UINTN) (*FreeMemoryTop - *FreeMemoryBottom) < Padding) {
+    DEBUG ((DEBUG_ERROR, "AllocatePages failed: Out of space after padding.\n"));
+    return EFI_OUT_OF_RESOURCES;
+  }
+
+  *(FreeMemoryTop) -= Padding;
+  if (Padding >= EFI_PAGE_SIZE) {
+    //
+    // Create a memory allocation HOB to cover
+    // the pages that we will lose to rounding
+    //
+    BuildMemoryAllocationHob (
+      *(FreeMemoryTop),
+      Padding & ~(UINTN)EFI_PAGE_MASK,
+      EfiConventionalMemory
+      );
+  }
 
   //
   // Verify that there is sufficient memory to satisfy the allocation.
@@ -192,6 +226,7 @@ PeiAllocatePages (
   //
   // The number of remaining pages needs to be greater than or equal to that of the request pages.
   //
+  Pages = ALIGN_VALUE (Pages, EFI_SIZE_TO_PAGES (Granularity));
   if (RemainingPages < Pages) {
     DEBUG ((EFI_D_ERROR, "AllocatePages failed: No 0x%lx Pages is available.\n", (UINT64) Pages));
     DEBUG ((EFI_D_ERROR, "There is only left 0x%lx pages memory resource to be allocated.\n", (UINT64) RemainingPages));
-- 
2.7.4