ArmPkg/ArmMmuLib ARM: use AllocateAlignedPages() for alignment

Instead of overallocating memory and align the resulting base address
manually, use the AllocateAlignedPages () helper, which achieves the
same, and might even manage that without leaking a chunk of memory of
the same size as the allocation itself.

While at it, fix up a variable declaration in the same hunk, and drop
a comment whose contents add nothing to the following line of code.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

1 files changed, 10 insertions, 9 deletions

diff --git a/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c b/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c
index aca7a37fac..e882e6e200 100644
--- a/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c
+++ b/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c
@@ -138,8 +138,9 @@ PopulateLevel2PageTable (
       // Case where a virtual memory map descriptor overlapped a section entry

 

       // Allocate a Level2 Page Table for this Section

-      TranslationTable = (UINTN)AllocatePages(EFI_SIZE_TO_PAGES(TRANSLATION_TABLE_PAGE_SIZE + TRANSLATION_TABLE_PAGE_ALIGNMENT));

-      TranslationTable = ((UINTN)TranslationTable + TRANSLATION_TABLE_PAGE_ALIGNMENT_MASK) & ~TRANSLATION_TABLE_PAGE_ALIGNMENT_MASK;

+      TranslationTable = (UINTN)AllocateAlignedPages (

+                                  EFI_SIZE_TO_PAGES (TRANSLATION_TABLE_PAGE_SIZE),

+                                  TRANSLATION_TABLE_PAGE_ALIGNMENT);

 

       // Translate the Section Descriptor into Page Descriptor

       SectionDescriptor = TT_DESCRIPTOR_PAGE_TYPE_PAGE | ConvertSectionAttributesToPageAttributes (*SectionEntry, FALSE);

@@ -162,9 +163,9 @@ PopulateLevel2PageTable (
       return;

     }

   } else {

-    TranslationTable = (UINTN)AllocatePages(EFI_SIZE_TO_PAGES(TRANSLATION_TABLE_PAGE_SIZE + TRANSLATION_TABLE_PAGE_ALIGNMENT));

-    TranslationTable = ((UINTN)TranslationTable + TRANSLATION_TABLE_PAGE_ALIGNMENT_MASK) & ~TRANSLATION_TABLE_PAGE_ALIGNMENT_MASK;

-

+    TranslationTable = (UINTN)AllocateAlignedPages (

+                                EFI_SIZE_TO_PAGES (TRANSLATION_TABLE_PAGE_SIZE),

+                                TRANSLATION_TABLE_PAGE_ALIGNMENT);

     ZeroMem ((VOID *)TranslationTable, TRANSLATION_TABLE_PAGE_SIZE);

 

     *SectionEntry = (TranslationTable & TT_DESCRIPTOR_SECTION_PAGETABLE_ADDRESS_MASK) |

@@ -289,16 +290,16 @@ ArmConfigureMmu (
   OUT UINTN                         *TranslationTableSize OPTIONAL

   )

 {

-  VOID*                         TranslationTable;

+  VOID                          *TranslationTable;

   ARM_MEMORY_REGION_ATTRIBUTES  TranslationTableAttribute;

   UINT32                        TTBRAttributes;

 

-  // Allocate pages for translation table.

-  TranslationTable = AllocatePages (EFI_SIZE_TO_PAGES (TRANSLATION_TABLE_SECTION_SIZE + TRANSLATION_TABLE_SECTION_ALIGNMENT));

+  TranslationTable = AllocateAlignedPages (

+                       EFI_SIZE_TO_PAGES (TRANSLATION_TABLE_SECTION_SIZE),

+                       TRANSLATION_TABLE_SECTION_ALIGNMENT);

   if (TranslationTable == NULL) {

     return RETURN_OUT_OF_RESOURCES;

   }

-  TranslationTable = (VOID*)(((UINTN)TranslationTable + TRANSLATION_TABLE_SECTION_ALIGNMENT_MASK) & ~TRANSLATION_TABLE_SECTION_ALIGNMENT_MASK);

 

   if (TranslationTableBase != NULL) {

     *TranslationTableBase = TranslationTable;