[edk2-devel] [PATCH v2] EmbeddedPkg/PrePiMemoryAllocationLib: Check for space on offset allocation

[Jeff Brasen via groups.io]

Update check for enough space to occur prior to alignment offset

modification. This prevents a case where EfiFreeMemoryTop could be

less than EfiFreeMemoryBottom



Signed-off-by: Jeff Brasen <jbrasen at nvidia.com>

---

 .../MemoryAllocationLib.c                     | 53 +++++++++++--------

 1 file changed, 30 insertions(+), 23 deletions(-)



diff --git a/EmbeddedPkg/Library/PrePiMemoryAllocationLib/MemoryAllocationLib.c b/EmbeddedPkg/Library/PrePiMemoryAllocationLib/MemoryAllocationLib.c

index 2cc2a71121..9208826565 100644

--- a/EmbeddedPkg/Library/PrePiMemoryAllocationLib/MemoryAllocationLib.c

+++ b/EmbeddedPkg/Library/PrePiMemoryAllocationLib/MemoryAllocationLib.c

@@ -27,37 +27,44 @@ InternalAllocatePages (

 

   Hob.Raw = GetHobList ();

 

-  // Check to see if on 4k boundary

   Offset = Hob.HandoffInformationTable->EfiFreeMemoryTop & 0xFFF;

+  //

+  // Verify that there is sufficient memory to satisfy the allocation and padding prior to updating anything

+  //

+  if ((Hob.HandoffInformationTable->EfiFreeMemoryTop - ((Pages * EFI_PAGE_SIZE) + sizeof (EFI_HOB_MEMORY_ALLOCATION)) - Offset) < Hob.HandoffInformationTable->EfiFreeMemoryBottom) {

+    if (Offset != 0) {

+      DEBUG ((DEBUG_ERROR, "Offset applied without enough space\r\n"));

+    } else {

+      DEBUG ((DEBUG_ERROR, "Out of memory\r\n"));

+    }

+

+    ASSERT (FALSE);

+    return 0;

+  }

+

+  // Check to see if on 4k boundary

   if (Offset != 0) {

     // If not aligned, make the allocation aligned.

     Hob.HandoffInformationTable->EfiFreeMemoryTop -= Offset;

   }

 

   //

-  // Verify that there is sufficient memory to satisfy the allocation

+  // Update the PHIT to reflect the memory usage

   //

-  if (Hob.HandoffInformationTable->EfiFreeMemoryTop - ((Pages * EFI_PAGE_SIZE) + sizeof (EFI_HOB_MEMORY_ALLOCATION)) < Hob.HandoffInformationTable->EfiFreeMemoryBottom) {

-    return 0;

-  } else {

-    //

-    // Update the PHIT to reflect the memory usage

-    //

-    Hob.HandoffInformationTable->EfiFreeMemoryTop -= Pages * EFI_PAGE_SIZE;

-

-    // This routine used to create a memory allocation HOB a la PEI, but that's not

-    // necessary for us.

-

-    //

-    // Create a memory allocation HOB.

-    //

-    BuildMemoryAllocationHob (

-      Hob.HandoffInformationTable->EfiFreeMemoryTop,

-      Pages * EFI_PAGE_SIZE,

-      MemoryType

-      );

-    return (VOID *)(UINTN)Hob.HandoffInformationTable->EfiFreeMemoryTop;

-  }

+  Hob.HandoffInformationTable->EfiFreeMemoryTop -= Pages * EFI_PAGE_SIZE;

+

+  // This routine used to create a memory allocation HOB a la PEI, but that's not

+  // necessary for us.

+

+  //

+  // Create a memory allocation HOB.

+  //

+  BuildMemoryAllocationHob (

+    Hob.HandoffInformationTable->EfiFreeMemoryTop,

+    Pages * EFI_PAGE_SIZE,

+    MemoryType

+    );

+  return (VOID *)(UINTN)Hob.HandoffInformationTable->EfiFreeMemoryTop;

 }

 

 /**

-- 

2.25.1





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