On Thu, 22 Sept 2022 at 22:40, Jeff Brasen <jbra...@nvidia.com> wrote:
>
> Update check for enough space to occur prior to alignment offset.
> This prevents cases where EfiFreeMemoryTop < EfiFreeMemoryBottom.
>
> Change-Id: I58c5d378523c881a4afc655e7ace4c009130c781
Thanks for respinning this. Care to add a signed-off-by ?
> ---
> .../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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