ArmPkg/CpuDxe: Added support to not set a memory region with the same attribute

Changing the attribute implies some cache management (clean & invalidate).
Preventing the cache management should improve the performance.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Olivier Martin <olivier.martin@arm.com>



git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@14568 6f19259b-4bc3-4df7-8a09-765794883524

1 files changed, 146 insertions, 0 deletions

diff --git a/ArmPkg/Drivers/CpuDxe/AArch64/Mmu.c b/ArmPkg/Drivers/CpuDxe/AArch64/Mmu.c
index 40a4c1b0aa..72f9b3cc63 100644
--- a/ArmPkg/Drivers/CpuDxe/AArch64/Mmu.c
+++ b/ArmPkg/Drivers/CpuDxe/AArch64/Mmu.c
@@ -194,3 +194,149 @@ SyncCacheConfig (
 

   return EFI_SUCCESS;

 }

+

+UINT64

+EfiAttributeToArmAttribute (

+  IN UINT64                    EfiAttributes

+  )

+{

+  UINT64 ArmAttributes;

+

+  switch (EfiAttributes & EFI_MEMORY_CACHETYPE_MASK) {

+  case EFI_MEMORY_UC:

+    ArmAttributes = TT_ATTR_INDX_DEVICE_MEMORY;

+    break;

+  case EFI_MEMORY_WC:

+    ArmAttributes = TT_ATTR_INDX_MEMORY_NON_CACHEABLE;

+    break;

+  case EFI_MEMORY_WT:

+    ArmAttributes = TT_ATTR_INDX_MEMORY_WRITE_THROUGH;

+    break;

+  case EFI_MEMORY_WB:

+    ArmAttributes = TT_ATTR_INDX_MEMORY_WRITE_BACK;

+    break;

+  default:

+    DEBUG ((EFI_D_ERROR, "EfiAttributeToArmAttribute: 0x%lX attributes is not supported.\n", EfiAttributes));

+    ASSERT (0);

+    ArmAttributes = TT_ATTR_INDX_DEVICE_MEMORY;

+  }

+

+  // Set the access flag to match the block attributes

+  ArmAttributes |= TT_AF;

+

+  // Determine protection attributes

+  if (EfiAttributes & EFI_MEMORY_WP) {

+    ArmAttributes |= TT_AP_RO_RO;

+  }

+

+  // Process eXecute Never attribute

+  if (EfiAttributes & EFI_MEMORY_XP) {

+    ArmAttributes |= TT_PXN_MASK;

+  }

+

+  return ArmAttributes;

+}

+

+// This function will recursively go down the page table to find the first block address linked to 'BaseAddress'.

+// And then the function will identify the size of the region that has the same page table attribute.

+EFI_STATUS

+GetMemoryRegionRec (

+  IN     UINT64                  *TranslationTable,

+  IN     UINTN                    TableLevel,

+  IN     UINT64                  *LastBlockEntry,

+  IN OUT UINTN                   *BaseAddress,

+  OUT    UINTN                   *RegionLength,

+  OUT    UINTN                   *RegionAttributes

+  )

+{

+  EFI_STATUS Status;

+  UINT64    *NextTranslationTable;

+  UINT64    *BlockEntry;

+  UINT64     BlockEntryType;

+  UINT64     EntryType;

+

+  if (TableLevel != 3) {

+    BlockEntryType = TT_TYPE_BLOCK_ENTRY;

+  } else {

+    BlockEntryType = TT_TYPE_BLOCK_ENTRY_LEVEL3;

+  }

+

+  // Find the block entry linked to the Base Address

+  BlockEntry = (UINT64*)TT_GET_ENTRY_FOR_ADDRESS (TranslationTable, TableLevel, *BaseAddress);

+  EntryType = *BlockEntry & TT_TYPE_MASK;

+

+  if (EntryType == TT_TYPE_TABLE_ENTRY) {

+    NextTranslationTable = (UINT64*)(*BlockEntry & TT_ADDRESS_MASK_DESCRIPTION_TABLE);

+

+    // The entry is a page table, so we go to the next level

+    Status = GetMemoryRegionRec (

+        NextTranslationTable, // Address of the next level page table

+        TableLevel + 1, // Next Page Table level

+        (UINTN*)TT_LAST_BLOCK_ADDRESS(NextTranslationTable, TT_ENTRY_COUNT),

+        BaseAddress, RegionLength, RegionAttributes);

+

+    // In case of 'Success', it means the end of the block region has been found into the upper

+    // level translation table

+    if (!EFI_ERROR(Status)) {

+      return EFI_SUCCESS;

+    }

+  } else if (EntryType == BlockEntryType) {

+    // We have found the BlockEntry attached to the address. We save its start address (the start

+    // address might be before the 'BaseAdress') and attributes

+    *BaseAddress      = *BaseAddress & ~(TT_ADDRESS_AT_LEVEL(TableLevel) - 1);

+    *RegionLength     = 0;

+    *RegionAttributes = *BlockEntry & TT_ATTRIBUTES_MASK;

+  } else {

+    // We have an 'Invalid' entry

+    return EFI_UNSUPPORTED;

+  }

+

+  while (BlockEntry <= LastBlockEntry) {

+    if ((*BlockEntry & TT_ATTRIBUTES_MASK) == *RegionAttributes) {

+      *RegionLength = *RegionLength + TT_BLOCK_ENTRY_SIZE_AT_LEVEL(TableLevel);

+    } else {

+      // In case we have found the end of the region we return success

+      return EFI_SUCCESS;

+    }

+    BlockEntry++;

+  }

+

+  // If we have reached the end of the TranslationTable and we have not found the end of the region then

+  // we return EFI_NOT_FOUND.

+  // The caller will continue to look for the memory region at its level

+  return EFI_NOT_FOUND;

+}

+

+EFI_STATUS

+GetMemoryRegion (

+  IN OUT UINTN                   *BaseAddress,

+  OUT    UINTN                   *RegionLength,

+  OUT    UINTN                   *RegionAttributes

+  )

+{

+  EFI_STATUS  Status;

+  UINT64     *TranslationTable;

+  UINTN       TableLevel;

+  UINTN       EntryCount;

+  UINTN       T0SZ;

+

+  ASSERT ((BaseAddress != NULL) && (RegionLength != NULL) && (RegionAttributes != NULL));

+

+  TranslationTable = ArmGetTTBR0BaseAddress ();

+

+  T0SZ = ArmGetTCR () & TCR_T0SZ_MASK;

+  // Get the Table info from T0SZ

+  GetRootTranslationTableInfo (T0SZ, &TableLevel, &EntryCount);

+

+  Status = GetMemoryRegionRec (TranslationTable, TableLevel,

+      (UINTN*)TT_LAST_BLOCK_ADDRESS(TranslationTable, EntryCount),

+      BaseAddress, RegionLength, RegionAttributes);

+

+  // If the region continues up to the end of the root table then GetMemoryRegionRec()

+  // will return EFI_NOT_FOUND

+  if (Status == EFI_NOT_FOUND) {

+    return EFI_SUCCESS;

+  } else {

+    return Status;

+  }

+}