Re: [edk2-devel] [PATCH 03/10] EmbeddedPkg/MemoryAllocationLib: Add null stub for AllocateCopyPool

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

On Tue, 14 Dec 2021 at 14:42, Min Xu <min.m.xu@intel.com> wrote:
>
> RFC: https://bugzilla.tianocore.org/show_bug.cgi?id=3429
>
> This function is a null stub to make the build success.
>
> Cc: Michael D Kinney <michael.d.kinney@intel.com>
> Cc: Brijesh Singh <brijesh.singh@amd.com>
> Cc: Erdem Aktas <erdemaktas@google.com>
> Cc: James Bottomley <jejb@linux.ibm.com>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Tom Lendacky <thomas.lendacky@amd.com>
> Cc: Gerd Hoffmann <kraxel@redhat.com>
> Cc: Leif Lindholm <leif@nuviainc.com>
> Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
> Cc: Abner Chang <abner.chang@hpe.com>
> Cc: Daniel Schaefer <daniel.schaefer@hpe.com>
> Signed-off-by: Min Xu <min.m.xu@intel.com>
> ---
>  .../MemoryAllocationLib.c                     | 28 +++++++++++++++++++
>  1 file changed, 28 insertions(+)
>

Why is it justified to implement a broken version of this routine?
This is not a NULL library class that only exists for build test
purposes, it is actually used in production builds.

If the TDVF code needs the symbol but does not actually call it,
perhaps there is another place where this should get fixed?


> diff --git a/EmbeddedPkg/Library/PrePiMemoryAllocationLib/MemoryAllocationLib.c b/EmbeddedPkg/Library/PrePiMemoryAllocationLib/MemoryAllocationLib.c
> index 78f8da5e9527..ddc27150c680 100644
> --- a/EmbeddedPkg/Library/PrePiMemoryAllocationLib/MemoryAllocationLib.c
> +++ b/EmbeddedPkg/Library/PrePiMemoryAllocationLib/MemoryAllocationLib.c
> @@ -220,6 +220,34 @@ AllocateZeroPool (
>    return Buffer;
>  }
>
> +/**
> +  Copies a buffer to an allocated buffer of type EfiBootServicesData.
> +
> +  Allocates the number bytes specified by AllocationSize of type EfiBootServicesData, copies
> +  AllocationSize bytes from Buffer to the newly allocated buffer, and returns a pointer to the
> +  allocated buffer.  If AllocationSize 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 Buffer is NULL, then ASSERT().
> +  If AllocationSize is greater than (MAX_ADDRESS - Buffer + 1), then ASSERT().
> +
> +  @param  AllocationSize        The number of bytes to allocate and zero.
> +  @param  Buffer                The buffer to copy to the allocated buffer.
> +
> +  @return A pointer to the allocated buffer or NULL if allocation fails.
> +
> +**/
> +VOID *
> +EFIAPI
> +AllocateCopyPool (
> +  IN UINTN       AllocationSize,
> +  IN CONST VOID  *Buffer
> +  )
> +{
> +  ASSERT (FALSE);
> +  return NULL;
> +}
> +
>  /**
>    Frees a buffer that was previously allocated with one of the pool allocation functions in the
>    Memory Allocation Library.
> --
> 2.29.2.windows.2
>
>
>
> 
>
>