On Thu, 30 Jun 2022 at 21:06, Jeff Brasen <jbra...@nvidia.com> wrote:
>
> Update check for enough space to occur prior to alignment offset.
> This prevents cases where EfiFreeMemoryTop < EfiFreeMemoryBottom.
>
So prior to this patch, we would
- check for enough space
- apply the alignment
- potentially exceed the available space due to alignment padding?
> Signed-off-by: Jeff Brasen <jbra...@nvidia.com>
This patch got mangled so I cannot apply it from the list.
> ---
> .../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 78f8da5e95..1956d644c3 100644
> --- a/EmbeddedPkg/Library/PrePiMemoryAllocationLib/MemoryAllocationLib.c
> +++ b/EmbeddedPkg/Library/PrePiMemoryAllocationLib/MemoryAllocationLib.c
> @@ -38,37 +38,44 @@ AllocatePages (
>
> 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,
> - EfiBootServicesData
> - );
> - 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,
> + EfiBootServicesData
> + );
> + return (VOID *)(UINTN)Hob.HandoffInformationTable->EfiFreeMemoryTop;
> }
>
> /**
> --
> 2.25.1
>
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