Re: [PATCH v3] MdeModulePkg/PeiCore: honour minimal runtime allocation granularity

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On 3 March 2017 at 09:43, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> Architectures such as AArch64 may run the OS with 16 KB or 64 KB sized
> pages, and for this reason, the UEFI spec mandates a minimal allocation
> granularity of 64 KB for regions that may require different memory
> attributes at OS runtime.
>
> So make PeiCore's implementation of AllocatePages () take this into
> account as well.
>
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
> v3: allocate a memory allocation HOB to cover the memory lost to rounding
>
>  MdeModulePkg/Core/Pei/Memory/MemoryServices.c | 39 +++++++++++++++++++-
>  MdeModulePkg/Core/Pei/PeiMain.h               | 18 +++++++++
>  2 files changed, 55 insertions(+), 2 deletions(-)
>
> diff --git a/MdeModulePkg/Core/Pei/Memory/MemoryServices.c b/MdeModulePkg/Core/Pei/Memory/MemoryServices.c
> index 4efe14313ca5..573fd606b4cc 100644
> --- a/MdeModulePkg/Core/Pei/Memory/MemoryServices.c
> +++ b/MdeModulePkg/Core/Pei/Memory/MemoryServices.c
> @@ -140,6 +140,8 @@ PeiAllocatePages (
>    EFI_PHYSICAL_ADDRESS                    *FreeMemoryTop;
>    EFI_PHYSICAL_ADDRESS                    *FreeMemoryBottom;
>    UINTN                                   RemainingPages;
> +  UINTN                                   Granularity;
> +  UINTN                                   Padding;
>
>    if ((MemoryType != EfiLoaderCode) &&
>        (MemoryType != EfiLoaderData) &&
> @@ -153,6 +155,20 @@ PeiAllocatePages (
>      return EFI_INVALID_PARAMETER;
>    }
>
> +  Granularity = DEFAULT_PAGE_ALLOCATION_GRANULARITY;
> +
> +  if  (RUNTIME_PAGE_ALLOCATION_GRANULARITY > DEFAULT_PAGE_ALLOCATION_GRANULARITY &&
> +       (MemoryType == EfiACPIReclaimMemory   ||
> +        MemoryType == EfiACPIMemoryNVS       ||
> +        MemoryType == EfiRuntimeServicesCode ||
> +        MemoryType == EfiRuntimeServicesData)) {
> +
> +    Granularity = RUNTIME_PAGE_ALLOCATION_GRANULARITY;
> +
> +    DEBUG ((DEBUG_INFO, "AllocatePages: rounding up allocation to %d KB\n",
> +      Granularity));

this needs to be divided by SIZE_1KB

> +  }
> +
>    PrivateData = PEI_CORE_INSTANCE_FROM_PS_THIS (PeiServices);
>    Hob.Raw     = PrivateData->HobList.Raw;
>
> @@ -176,9 +192,27 @@ PeiAllocatePages (
>    }
>
>    //
> -  // Check to see if on 4k boundary, If not aligned, make the allocation aligned.
> +  // Check to see if on correct boundary for the memory type.
> +  // If not aligned, make the allocation aligned.
>    //
> -  *(FreeMemoryTop) -= *(FreeMemoryTop) & 0xFFF;
> +  Padding = *(FreeMemoryTop) & (Granularity - 1);
> +  if ((UINTN) (*FreeMemoryTop - *FreeMemoryBottom) < Padding) {
> +    DEBUG ((DEBUG_ERROR, "AllocatePages failed: Out of space after padding.\n"));
> +    return EFI_OUT_OF_RESOURCES;
> +  }
> +
> +  *(FreeMemoryTop) -= Padding;
> +  if (Padding >= EFI_PAGE_SIZE) {
> +    //
> +    // Create a memory allocation HOB to cover
> +    // the pages that we will lose to rounding
> +    //
> +    BuildMemoryAllocationHob (
> +      *(FreeMemoryTop),
> +      Padding & ~((UINTN)EFI_PAGE_SIZE - 1),
> +      EfiConventionalMemory
> +      );
> +  }
>
>    //
>    // Verify that there is sufficient memory to satisfy the allocation.
> @@ -192,6 +226,7 @@ PeiAllocatePages (
>    //
>    // The number of remaining pages needs to be greater than or equal to that of the request pages.
>    //
> +  Pages = ALIGN_VALUE (Pages, EFI_SIZE_TO_PAGES (Granularity));
>    if (RemainingPages < Pages) {
>      DEBUG ((EFI_D_ERROR, "AllocatePages failed: No 0x%lx Pages is available.\n", (UINT64) Pages));
>      DEBUG ((EFI_D_ERROR, "There is only left 0x%lx pages memory resource to be allocated.\n", (UINT64) RemainingPages));
> diff --git a/MdeModulePkg/Core/Pei/PeiMain.h b/MdeModulePkg/Core/Pei/PeiMain.h
> index 69eea514920b..e8358d3c4e6d 100644
> --- a/MdeModulePkg/Core/Pei/PeiMain.h
> +++ b/MdeModulePkg/Core/Pei/PeiMain.h
> @@ -55,6 +55,24 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
>  ///
>  #define PEI_CORE_INTERNAL_FFS_FILE_DISPATCH_TYPE   0xff
>
> +#if defined (MDE_CPU_AARCH64)
> +///
> +/// 64-bit ARM systems allow the OS to execute with 64 KB page size,
> +/// so for improved interoperability with the firmware, align the
> +/// runtime regions to 64 KB as well
> +///
> +#define RUNTIME_PAGE_ALLOCATION_GRANULARITY       (SIZE_64KB)
> +#define DEFAULT_PAGE_ALLOCATION_GRANULARITY       (EFI_PAGE_SIZE)
> +
> +#else
> +///
> +/// For generic EFI machines make the default allocations 4K aligned
> +///
> +#define RUNTIME_PAGE_ALLOCATION_GRANULARITY       (EFI_PAGE_SIZE)
> +#define DEFAULT_PAGE_ALLOCATION_GRANULARITY       (EFI_PAGE_SIZE)
> +
> +#endif
> +
>  ///
>  /// Pei Core private data structures
>  ///
> --
> 2.7.4
>