BaseTools/GenFv: optimize away redundant padding

To prevent double padding of XIP modules leading to excessive
waste of FV space, try to adjust existing padding rather than
adding more.

Instead of adding a pad file to the FV to line up an FFS file that
itself may contain padding to line up the payload, try to find a
dedicated padding section inside the FFS, and reduce its size to
place all subsequent aligned FFS section at their respective minimum
alignments.

When using 4 KB section alignment (which is required on AARCH64 in
some cases), this will save 4 KB for each XIP module.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Reviewed-by: Yingke Liu <yingke.d.liu@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18080 6f19259b-4bc3-4df7-8a09-765794883524

1 files changed, 161 insertions, 8 deletions

diff --git a/BaseTools/Source/C/GenFv/GenFvInternalLib.c b/BaseTools/Source/C/GenFv/GenFvInternalLib.c
index 005098508b..6d2d5d1f8c 100644
--- a/BaseTools/Source/C/GenFv/GenFvInternalLib.c
+++ b/BaseTools/Source/C/GenFv/GenFvInternalLib.c
@@ -31,6 +31,8 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 #endif

 #include <assert.h>

 

+#include <Guid/FfsSectionAlignmentPadding.h>

+

 #include "GenFvInternalLib.h"

 #include "FvLib.h"

 #include "PeCoffLib.h"

@@ -39,10 +41,11 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 BOOLEAN mArm = FALSE;

 STATIC UINT32   MaxFfsAlignment = 0;

 

-EFI_GUID  mEfiFirmwareVolumeTopFileGuid = EFI_FFS_VOLUME_TOP_FILE_GUID;

+EFI_GUID  mEfiFirmwareVolumeTopFileGuid       = EFI_FFS_VOLUME_TOP_FILE_GUID;

 EFI_GUID  mFileGuidArray [MAX_NUMBER_OF_FILES_IN_FV];

-EFI_GUID  mZeroGuid                 = {0x0, 0x0, 0x0, {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}};

-EFI_GUID  mDefaultCapsuleGuid       = {0x3B6686BD, 0x0D76, 0x4030, { 0xB7, 0x0E, 0xB5, 0x51, 0x9E, 0x2F, 0xC5, 0xA0 }};

+EFI_GUID  mZeroGuid                           = {0x0, 0x0, 0x0, {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}};

+EFI_GUID  mDefaultCapsuleGuid                 = {0x3B6686BD, 0x0D76, 0x4030, { 0xB7, 0x0E, 0xB5, 0x51, 0x9E, 0x2F, 0xC5, 0xA0 }};

+EFI_GUID  mEfiFfsSectionAlignmentPaddingGuid  = EFI_FFS_SECTION_ALIGNMENT_PADDING_GUID;

 

 CHAR8      *mFvbAttributeName[] = {

   EFI_FVB2_READ_DISABLED_CAP_STRING, 

@@ -934,6 +937,153 @@ Returns:
   return EFI_SUCCESS;

 }

 

+STATIC

+BOOLEAN

+AdjustInternalFfsPadding (

+  IN OUT  EFI_FFS_FILE_HEADER   *FfsFile,

+  IN OUT  MEMORY_FILE           *FvImage,

+  IN      UINTN                 Alignment,

+  IN OUT  UINTN                 *FileSize

+  )

+/*++

+

+Routine Description:

+

+  This function looks for a dedicated alignment padding section in the FFS, and

+  shrinks it to the size required to line up subsequent sections correctly.

+

+Arguments:

+

+  FfsFile               A pointer to Ffs file image.

+  FvImage               The memory image of the FV to adjust it to.

+  Alignment             Current file alignment

+  FileSize              Reference to a variable holding the size of the FFS file

+

+Returns:

+

+  TRUE                  Padding section was found and updated successfully

+  FALSE                 Otherwise

+

+--*/

+{

+  EFI_FILE_SECTION_POINTER  PadSection;

+  UINT8                     *Remainder;

+  EFI_STATUS                Status;

+  UINT32                    FfsHeaderLength;

+  UINT32                    FfsFileLength;

+  UINT32                    PadSize;

+  UINTN                     Misalignment;

+  EFI_FFS_INTEGRITY_CHECK   *IntegrityCheck;

+

+  //

+  // Figure out the misalignment: all FFS sections are aligned relative to the

+  // start of the FFS payload, so use that as the base of the misalignment

+  // computation.

+  //

+  FfsHeaderLength = GetFfsHeaderLength(FfsFile);

+  Misalignment = (UINTN) FvImage->CurrentFilePointer -

+                 (UINTN) FvImage->FileImage + FfsHeaderLength;

+  Misalignment &= Alignment - 1;

+  if (Misalignment == 0) {

+    // Nothing to do, return success

+    return TRUE;

+  }

+

+  //

+  // We only apply this optimization to FFS files with the FIXED attribute set,

+  // since the FFS will not be loadable at arbitrary offsets anymore after

+  // we adjust the size of the padding section.

+  //

+  if ((FfsFile->Attributes & FFS_ATTRIB_FIXED) == 0) {

+    return FALSE;

+  }

+

+  //

+  // Look for a dedicated padding section that we can adjust to compensate

+  // for the misalignment. If such a padding section exists, it precedes all

+  // sections with alignment requirements, and so the adjustment will correct

+  // all of them.

+  //

+  Status = GetSectionByType (FfsFile, EFI_SECTION_FREEFORM_SUBTYPE_GUID, 1,

+             &PadSection);

+  if (EFI_ERROR (Status) ||

+      CompareGuid (&PadSection.FreeformSubtypeSection->SubTypeGuid,

+        &mEfiFfsSectionAlignmentPaddingGuid) != 0) {

+    return FALSE;

+  }

+

+  //

+  // Find out if the size of the padding section is sufficient to compensate

+  // for the misalignment.

+  //

+  PadSize = GetSectionFileLength (PadSection.CommonHeader);

+  if (Misalignment > PadSize - sizeof (EFI_FREEFORM_SUBTYPE_GUID_SECTION)) {

+    return FALSE;

+  }

+

+  //

+  // Move the remainder of the FFS file towards the front, and adjust the

+  // file size output parameter.

+  //

+  Remainder = (UINT8 *) PadSection.CommonHeader + PadSize;

+  memmove (Remainder - Misalignment, Remainder,

+           *FileSize - (UINTN) (Remainder - (UINTN) FfsFile));

+  *FileSize -= Misalignment;

+

+  //

+  // Update the padding section's length with the new values. Note that the

+  // padding is always < 64 KB, so we can ignore EFI_COMMON_SECTION_HEADER2

+  // ExtendedSize.

+  //

+  PadSize -= Misalignment;

+  PadSection.CommonHeader->Size[0] = (UINT8) (PadSize & 0xff);

+  PadSection.CommonHeader->Size[1] = (UINT8) ((PadSize & 0xff00) >> 8);

+  PadSection.CommonHeader->Size[2] = (UINT8) ((PadSize & 0xff0000) >> 16);

+

+  //

+  // Update the FFS header with the new overall length

+  //

+  FfsFileLength = GetFfsFileLength (FfsFile) - Misalignment;

+  if (FfsHeaderLength > sizeof(EFI_FFS_FILE_HEADER)) {

+    ((EFI_FFS_FILE_HEADER2 *)FfsFile)->ExtendedSize = FfsFileLength;

+  } else {

+    FfsFile->Size[0] = (UINT8) (FfsFileLength & 0x000000FF);

+    FfsFile->Size[1] = (UINT8) ((FfsFileLength & 0x0000FF00) >> 8);

+    FfsFile->Size[2] = (UINT8) ((FfsFileLength & 0x00FF0000) >> 16);

+  }

+

+  //

+  // Clear the alignment bits: these have become meaningless now that we have

+  // adjusted the padding section.

+  //

+  FfsFile->Attributes &= ~FFS_ATTRIB_DATA_ALIGNMENT;

+

+  //

+  // Recalculate the FFS header checksum. Instead of setting Header and State

+  // both to zero, set Header to (UINT8)(-State) so State preserves its original

+  // value

+  //

+  IntegrityCheck = &FfsFile->IntegrityCheck;

+  IntegrityCheck->Checksum.Header = (UINT8) (0x100 - FfsFile->State);

+  IntegrityCheck->Checksum.File = 0;

+

+  IntegrityCheck->Checksum.Header = CalculateChecksum8 (

+                                      (UINT8 *) FfsFile, FfsHeaderLength);

+

+  if (FfsFile->Attributes & FFS_ATTRIB_CHECKSUM) {

+    //

+    // Ffs header checksum = zero, so only need to calculate ffs body.

+    //

+    IntegrityCheck->Checksum.File = CalculateChecksum8 (

+                                      (UINT8 *) FfsFile + FfsHeaderLength,

+                                      FfsFileLength - FfsHeaderLength);

+  } else {

+    IntegrityCheck->Checksum.File = FFS_FIXED_CHECKSUM;

+  }

+

+  return TRUE;

+}

+

 EFI_STATUS

 AddFile (

   IN OUT MEMORY_FILE          *FvImage,

@@ -1140,11 +1290,14 @@ Returns:
   //

   // Add pad file if necessary

   //

-  Status = AddPadFile (FvImage, 1 << CurrentFileAlignment, *VtfFileImage, NULL, FileSize);

-  if (EFI_ERROR (Status)) {

-    Error (NULL, 0, 4002, "Resource", "FV space is full, could not add pad file for data alignment property.");

-    free (FileBuffer);

-    return EFI_ABORTED;

+  if (!AdjustInternalFfsPadding ((EFI_FFS_FILE_HEADER *) FileBuffer, FvImage,

+         1 << CurrentFileAlignment, &FileSize)) {

+    Status = AddPadFile (FvImage, 1 << CurrentFileAlignment, *VtfFileImage, NULL, FileSize);

+    if (EFI_ERROR (Status)) {

+      Error (NULL, 0, 4002, "Resource", "FV space is full, could not add pad file for data alignment property.");

+      free (FileBuffer);

+      return EFI_ABORTED;

+    }

   }

   //

   // Add file