ArmPkg/UncachedMemoryAllocationLib: restore mapping attributes after free

In order to play nice with platforms that use strict memory permission
policies, restore the original mapping attributes when freeing uncached
allocations.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>

1 files changed, 7 insertions, 9 deletions

diff --git a/ArmPkg/Library/UncachedMemoryAllocationLib/UncachedMemoryAllocationLib.c b/ArmPkg/Library/UncachedMemoryAllocationLib/UncachedMemoryAllocationLib.c
index f6c692f9a4..cd13a7da92 100644
--- a/ArmPkg/Library/UncachedMemoryAllocationLib/UncachedMemoryAllocationLib.c
+++ b/ArmPkg/Library/UncachedMemoryAllocationLib/UncachedMemoryAllocationLib.c
@@ -42,11 +42,6 @@ UncachedInternalAllocateAlignedPages (
 

 

 

-//

-// Assume all of memory has the same cache attributes, unless we do our magic

-//

-UINT64  gAttributes;

-

 typedef struct {

   EFI_PHYSICAL_ADDRESS  Base;

   VOID                  *Allocation;

@@ -54,6 +49,7 @@ typedef struct {
   EFI_MEMORY_TYPE       MemoryType;

   BOOLEAN               Allocated;

   LIST_ENTRY            Link;

+  UINT64                Attributes;

 } FREE_PAGE_NODE;

 

 STATIC LIST_ENTRY  mPageList = INITIALIZE_LIST_HEAD_VARIABLE (mPageList);

@@ -153,10 +149,7 @@ AllocatePagesFromList (
   }

 

   Status = gDS->GetMemorySpaceDescriptor (Memory, &Descriptor);

-  if (!EFI_ERROR (Status)) {

-    // We are making an assumption that all of memory has the same default attributes

-    gAttributes = Descriptor.Attributes;

-  } else {

+  if (EFI_ERROR (Status)) {

     gBS->FreePages (Memory, Pages);

     return Status;

   }

@@ -181,6 +174,7 @@ AllocatePagesFromList (
   NewNode->Pages      = Pages;

   NewNode->Allocated  = TRUE;

   NewNode->MemoryType = MemoryType;

+  NewNode->Attributes = Descriptor.Attributes;

 

   InsertTailList (&mPageList, &NewNode->Link);

 

@@ -266,6 +260,10 @@ UncachedMemoryAllocationLibDestructor (
     // We only free the non-allocated buffer

     if (OldNode->Allocated == FALSE) {

       gBS->FreePages ((EFI_PHYSICAL_ADDRESS)(UINTN)OldNode->Base, OldNode->Pages);

+

+      gDS->SetMemorySpaceAttributes ((EFI_PHYSICAL_ADDRESS)(UINTN)OldNode->Base,

+             EFI_PAGES_TO_SIZE (OldNode->Pages), OldNode->Attributes);

+

       RemoveEntryList (&OldNode->Link);

       FreePool (OldNode);

     }