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[edk2-devel] [PATCH v3] EmbeddedPkg/PrePiMemoryAllocationLib: Add check for space on offset allocation

Jeff Brasen via groups.io posted 1 patch 3 years, 4 months ago
Failed in applying to current master (apply log)
1 file changed, 21 insertions(+), 27 deletions(-)
[edk2-devel] [PATCH v3] EmbeddedPkg/PrePiMemoryAllocationLib: Add check for space on offset allocation
Posted by Jeff Brasen via groups.io 3 years, 4 months ago 
Update check for enough space to occur prior to alignment offset.

This prevents cases where EfiFreeMemoryTop < EfiFreeMemoryBottom.



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

---

 .../MemoryAllocationLib.c                     | 48 ++++++++-----------

 1 file changed, 21 insertions(+), 27 deletions(-)



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

index 2cc2a71121..08a0add340 100644

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

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

@@ -23,41 +23,35 @@ InternalAllocatePages (

   )

 {

   EFI_PEI_HOB_POINTERS  Hob;

-  EFI_PHYSICAL_ADDRESS  Offset;

+  EFI_PHYSICAL_ADDRESS  NewTop;

 

   Hob.Raw = GetHobList ();

 

-  // Check to see if on 4k boundary

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

-  if (Offset != 0) {

-    // If not aligned, make the allocation aligned.

-    Hob.HandoffInformationTable->EfiFreeMemoryTop -= Offset;

-  }

+  NewTop  = Hob.HandoffInformationTable->EfiFreeMemoryTop & ~(EFI_PHYSICAL_ADDRESS)EFI_PAGE_MASK;

+  NewTop -= Pages * EFI_PAGE_SIZE;

 

   //

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

   //

-  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;

+  if (NewTop < (Hob.HandoffInformationTable->EfiFreeMemoryBottom + sizeof (EFI_HOB_MEMORY_ALLOCATION))) {

+    return NULL;

   }

+

+  //

+  // Update the PHIT to reflect the memory usage

+  //

+  Hob.HandoffInformationTable->EfiFreeMemoryTop = NewTop;

+

+  //

+  // 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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Re: [edk2-devel] [PATCH v3] EmbeddedPkg/PrePiMemoryAllocationLib: Add check for space on offset allocation
Posted by Ard Biesheuvel 3 years, 4 months ago 
On Fri, 23 Sept 2022 at 17:56, Jeff Brasen <jbrasen@nvidia.com> wrote:
>
> Update check for enough space to occur prior to alignment offset.
> This prevents cases where EfiFreeMemoryTop < EfiFreeMemoryBottom.
>
> Signed-off-by: Jeff Brasen <jbrasen@nvidia.com>

Merged as #3396

Thanks,

> ---
>  .../MemoryAllocationLib.c                     | 48 ++++++++-----------
>  1 file changed, 21 insertions(+), 27 deletions(-)
>
> diff --git a/EmbeddedPkg/Library/PrePiMemoryAllocationLib/MemoryAllocationLib.c b/EmbeddedPkg/Library/PrePiMemoryAllocationLib/MemoryAllocationLib.c
> index 2cc2a71121..08a0add340 100644
> --- a/EmbeddedPkg/Library/PrePiMemoryAllocationLib/MemoryAllocationLib.c
> +++ b/EmbeddedPkg/Library/PrePiMemoryAllocationLib/MemoryAllocationLib.c
> @@ -23,41 +23,35 @@ InternalAllocatePages (
>    )
>  {
>    EFI_PEI_HOB_POINTERS  Hob;
> -  EFI_PHYSICAL_ADDRESS  Offset;
> +  EFI_PHYSICAL_ADDRESS  NewTop;
>
>    Hob.Raw = GetHobList ();
>
> -  // Check to see if on 4k boundary
> -  Offset = Hob.HandoffInformationTable->EfiFreeMemoryTop & 0xFFF;
> -  if (Offset != 0) {
> -    // If not aligned, make the allocation aligned.
> -    Hob.HandoffInformationTable->EfiFreeMemoryTop -= Offset;
> -  }
> +  NewTop  = Hob.HandoffInformationTable->EfiFreeMemoryTop & ~(EFI_PHYSICAL_ADDRESS)EFI_PAGE_MASK;
> +  NewTop -= Pages * EFI_PAGE_SIZE;
>
>    //
>    // Verify that there is sufficient memory to satisfy the allocation
>    //
> -  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;
> +  if (NewTop < (Hob.HandoffInformationTable->EfiFreeMemoryBottom + sizeof (EFI_HOB_MEMORY_ALLOCATION))) {
> +    return NULL;
>    }
> +
> +  //
> +  // Update the PHIT to reflect the memory usage
> +  //
> +  Hob.HandoffInformationTable->EfiFreeMemoryTop = NewTop;
> +
> +  //
> +  // 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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