Re: [edk2-devel] [PATCH] EmbeddedPkg/PrePiMemoryAllocationLib: Add ReallocatePool

["Ard Biesheuvel" <ardb@kernel.org>]

On Mon, 11 Dec 2023 at 16:48, Jeff Brasen <jbrasen@nvidia.com> wrote:
>
> Add implementation of ReallocatePool which is defined in the
> MemoryAllocationLib header file to allow components to not
> need special handling for PrePi module types.
>
> Signed-off-by: Jeff Brasen <jbrasen@nvidia.com>

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>

> ---
>  .../MemoryAllocationLib.c                     | 57 +++++++++++++++++++
>  1 file changed, 57 insertions(+)
>
> diff --git a/EmbeddedPkg/Library/PrePiMemoryAllocationLib/MemoryAllocationLib.c b/EmbeddedPkg/Library/PrePiMemoryAllocationLib/MemoryAllocationLib.c
> index 08a0add340..39fbe243dd 100644
> --- a/EmbeddedPkg/Library/PrePiMemoryAllocationLib/MemoryAllocationLib.c
> +++ b/EmbeddedPkg/Library/PrePiMemoryAllocationLib/MemoryAllocationLib.c
> @@ -269,3 +269,60 @@ FreePool (
>  {
>    // Not implemented yet
>  }
> +
> +/**
> +  Reallocates a buffer of type EfiBootServicesData.
> +
> +  Allocates and zeros the number bytes specified by NewSize from memory of type
> +  EfiBootServicesData.  If OldBuffer is not NULL, then the smaller of OldSize and
> +  NewSize bytes are copied from OldBuffer to the newly allocated buffer, and
> +  OldBuffer is freed.  A pointer to the newly allocated buffer is returned.
> +  If NewSize is 0, then a valid buffer of 0 size is  returned.  If there is not
> +  enough memory remaining to satisfy the request, then NULL is returned.
> +
> +  If the allocation of the new buffer is successful and the smaller of NewSize and OldSize
> +  is greater than (MAX_ADDRESS - OldBuffer + 1), then ASSERT().
> +
> +  @param  OldSize        The size, in bytes, of OldBuffer.
> +  @param  NewSize        The size, in bytes, of the buffer to reallocate.
> +  @param  OldBuffer      The buffer to copy to the allocated buffer.  This is an optional
> +                         parameter that may be NULL.
> +
> +  @return A pointer to the allocated buffer or NULL if allocation fails.
> +
> +**/
> +VOID *
> +EFIAPI
> +ReallocatePool (
> +  IN UINTN  OldSize,
> +  IN UINTN  NewSize,
> +  IN VOID   *OldBuffer  OPTIONAL
> +  )
> +{
> +  VOID  *NewBuffer;
> +
> +  // Validate the OldBuffer is HobAllocated.
> +  DEBUG_CODE_BEGIN ();
> +  EFI_HOB_HANDOFF_INFO_TABLE  *HandOffHob;
> +
> +  if (OldBuffer != NULL) {
> +    HandOffHob = GetHobList ();
> +    ASSERT (((EFI_PHYSICAL_ADDRESS)OldBuffer >= HandOffHob->EfiMemoryBottom));
> +    ASSERT (((EFI_PHYSICAL_ADDRESS)(OldBuffer + OldSize) <= HandOffHob->EfiFreeMemoryBottom));
> +  }
> +
> +  DEBUG_CODE_END ();
> +
> +  // If new buffer would be smaller just return old buffer as FreePool isn't supported.
> +  if ((OldBuffer != NULL) && (OldSize >= NewSize)) {
> +    return OldBuffer;
> +  }
> +
> +  NewBuffer = AllocateZeroPool (NewSize);
> +  if ((NewBuffer != NULL) && (OldBuffer != NULL)) {
> +    CopyMem (NewBuffer, OldBuffer, MIN (OldSize, NewSize));
> +    FreePool (OldBuffer);
> +  }
> +
> +  return NewBuffer;
> +}
> --
> 2.34.1
>


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