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

diff --git a/BaseTools/Source/C/GenFv/GenFvInternalLib.c b/BaseTools/Source/C/GenFv/GenFvInternalLib.c
index 005098508b26023c14e0fa5b9dba306d3a9321c6..6d2d5d1f8c6710fd92d60619788afd4b9364b029 100644 (file)
--- 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\r
 #include <assert.h>\r
 \r
+#include <Guid/FfsSectionAlignmentPadding.h>\r
+\r
 #include "GenFvInternalLib.h"\r
 #include "FvLib.h"\r
 #include "PeCoffLib.h"\r
@@ -39,10 +41,11 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 BOOLEAN mArm = FALSE;\r
 STATIC UINT32   MaxFfsAlignment = 0;\r
 \r
-EFI_GUID  mEfiFirmwareVolumeTopFileGuid = EFI_FFS_VOLUME_TOP_FILE_GUID;\r
+EFI_GUID  mEfiFirmwareVolumeTopFileGuid       = EFI_FFS_VOLUME_TOP_FILE_GUID;\r
 EFI_GUID  mFileGuidArray [MAX_NUMBER_OF_FILES_IN_FV];\r
-EFI_GUID  mZeroGuid                 = {0x0, 0x0, 0x0, {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}};\r
-EFI_GUID  mDefaultCapsuleGuid       = {0x3B6686BD, 0x0D76, 0x4030, { 0xB7, 0x0E, 0xB5, 0x51, 0x9E, 0x2F, 0xC5, 0xA0 }};\r
+EFI_GUID  mZeroGuid                           = {0x0, 0x0, 0x0, {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}};\r
+EFI_GUID  mDefaultCapsuleGuid                 = {0x3B6686BD, 0x0D76, 0x4030, { 0xB7, 0x0E, 0xB5, 0x51, 0x9E, 0x2F, 0xC5, 0xA0 }};\r
+EFI_GUID  mEfiFfsSectionAlignmentPaddingGuid  = EFI_FFS_SECTION_ALIGNMENT_PADDING_GUID;\r
 \r
 CHAR8      *mFvbAttributeName[] = {\r
   EFI_FVB2_READ_DISABLED_CAP_STRING, \r
@@ -934,6 +937,153 @@ Returns:
   return EFI_SUCCESS;\r
 }\r
 \r
+STATIC\r
+BOOLEAN\r
+AdjustInternalFfsPadding (\r
+  IN OUT  EFI_FFS_FILE_HEADER   *FfsFile,\r
+  IN OUT  MEMORY_FILE           *FvImage,\r
+  IN      UINTN                 Alignment,\r
+  IN OUT  UINTN                 *FileSize\r
+  )\r
+/*++\r
+\r
+Routine Description:\r
+\r
+  This function looks for a dedicated alignment padding section in the FFS, and\r
+  shrinks it to the size required to line up subsequent sections correctly.\r
+\r
+Arguments:\r
+\r
+  FfsFile               A pointer to Ffs file image.\r
+  FvImage               The memory image of the FV to adjust it to.\r
+  Alignment             Current file alignment\r
+  FileSize              Reference to a variable holding the size of the FFS file\r
+\r
+Returns:\r
+\r
+  TRUE                  Padding section was found and updated successfully\r
+  FALSE                 Otherwise\r
+\r
+--*/\r
+{\r
+  EFI_FILE_SECTION_POINTER  PadSection;\r
+  UINT8                     *Remainder;\r
+  EFI_STATUS                Status;\r
+  UINT32                    FfsHeaderLength;\r
+  UINT32                    FfsFileLength;\r
+  UINT32                    PadSize;\r
+  UINTN                     Misalignment;\r
+  EFI_FFS_INTEGRITY_CHECK   *IntegrityCheck;\r
+\r
+  //\r
+  // Figure out the misalignment: all FFS sections are aligned relative to the\r
+  // start of the FFS payload, so use that as the base of the misalignment\r
+  // computation.\r
+  //\r
+  FfsHeaderLength = GetFfsHeaderLength(FfsFile);\r
+  Misalignment = (UINTN) FvImage->CurrentFilePointer -\r
+                 (UINTN) FvImage->FileImage + FfsHeaderLength;\r
+  Misalignment &= Alignment - 1;\r
+  if (Misalignment == 0) {\r
+    // Nothing to do, return success\r
+    return TRUE;\r
+  }\r
+\r
+  //\r
+  // We only apply this optimization to FFS files with the FIXED attribute set,\r
+  // since the FFS will not be loadable at arbitrary offsets anymore after\r
+  // we adjust the size of the padding section.\r
+  //\r
+  if ((FfsFile->Attributes & FFS_ATTRIB_FIXED) == 0) {\r
+    return FALSE;\r
+  }\r
+\r
+  //\r
+  // Look for a dedicated padding section that we can adjust to compensate\r
+  // for the misalignment. If such a padding section exists, it precedes all\r
+  // sections with alignment requirements, and so the adjustment will correct\r
+  // all of them.\r
+  //\r
+  Status = GetSectionByType (FfsFile, EFI_SECTION_FREEFORM_SUBTYPE_GUID, 1,\r
+             &PadSection);\r
+  if (EFI_ERROR (Status) ||\r
+      CompareGuid (&PadSection.FreeformSubtypeSection->SubTypeGuid,\r
+        &mEfiFfsSectionAlignmentPaddingGuid) != 0) {\r
+    return FALSE;\r
+  }\r
+\r
+  //\r
+  // Find out if the size of the padding section is sufficient to compensate\r
+  // for the misalignment.\r
+  //\r
+  PadSize = GetSectionFileLength (PadSection.CommonHeader);\r
+  if (Misalignment > PadSize - sizeof (EFI_FREEFORM_SUBTYPE_GUID_SECTION)) {\r
+    return FALSE;\r
+  }\r
+\r
+  //\r
+  // Move the remainder of the FFS file towards the front, and adjust the\r
+  // file size output parameter.\r
+  //\r
+  Remainder = (UINT8 *) PadSection.CommonHeader + PadSize;\r
+  memmove (Remainder - Misalignment, Remainder,\r
+           *FileSize - (UINTN) (Remainder - (UINTN) FfsFile));\r
+  *FileSize -= Misalignment;\r
+\r
+  //\r
+  // Update the padding section's length with the new values. Note that the\r
+  // padding is always < 64 KB, so we can ignore EFI_COMMON_SECTION_HEADER2\r
+  // ExtendedSize.\r
+  //\r
+  PadSize -= Misalignment;\r
+  PadSection.CommonHeader->Size[0] = (UINT8) (PadSize & 0xff);\r
+  PadSection.CommonHeader->Size[1] = (UINT8) ((PadSize & 0xff00) >> 8);\r
+  PadSection.CommonHeader->Size[2] = (UINT8) ((PadSize & 0xff0000) >> 16);\r
+\r
+  //\r
+  // Update the FFS header with the new overall length\r
+  //\r
+  FfsFileLength = GetFfsFileLength (FfsFile) - Misalignment;\r
+  if (FfsHeaderLength > sizeof(EFI_FFS_FILE_HEADER)) {\r
+    ((EFI_FFS_FILE_HEADER2 *)FfsFile)->ExtendedSize = FfsFileLength;\r
+  } else {\r
+    FfsFile->Size[0] = (UINT8) (FfsFileLength & 0x000000FF);\r
+    FfsFile->Size[1] = (UINT8) ((FfsFileLength & 0x0000FF00) >> 8);\r
+    FfsFile->Size[2] = (UINT8) ((FfsFileLength & 0x00FF0000) >> 16);\r
+  }\r
+\r
+  //\r
+  // Clear the alignment bits: these have become meaningless now that we have\r
+  // adjusted the padding section.\r
+  //\r
+  FfsFile->Attributes &= ~FFS_ATTRIB_DATA_ALIGNMENT;\r
+\r
+  //\r
+  // Recalculate the FFS header checksum. Instead of setting Header and State\r
+  // both to zero, set Header to (UINT8)(-State) so State preserves its original\r
+  // value\r
+  //\r
+  IntegrityCheck = &FfsFile->IntegrityCheck;\r
+  IntegrityCheck->Checksum.Header = (UINT8) (0x100 - FfsFile->State);\r
+  IntegrityCheck->Checksum.File = 0;\r
+\r
+  IntegrityCheck->Checksum.Header = CalculateChecksum8 (\r
+                                      (UINT8 *) FfsFile, FfsHeaderLength);\r
+\r
+  if (FfsFile->Attributes & FFS_ATTRIB_CHECKSUM) {\r
+    //\r
+    // Ffs header checksum = zero, so only need to calculate ffs body.\r
+    //\r
+    IntegrityCheck->Checksum.File = CalculateChecksum8 (\r
+                                      (UINT8 *) FfsFile + FfsHeaderLength,\r
+                                      FfsFileLength - FfsHeaderLength);\r
+  } else {\r
+    IntegrityCheck->Checksum.File = FFS_FIXED_CHECKSUM;\r
+  }\r
+\r
+  return TRUE;\r
+}\r
+\r
 EFI_STATUS\r
 AddFile (\r
   IN OUT MEMORY_FILE          *FvImage,\r
@@ -1140,11 +1290,14 @@ Returns:
   //\r
   // Add pad file if necessary\r
   //\r
-  Status = AddPadFile (FvImage, 1 << CurrentFileAlignment, *VtfFileImage, NULL, FileSize);\r
-  if (EFI_ERROR (Status)) {\r
-    Error (NULL, 0, 4002, "Resource", "FV space is full, could not add pad file for data alignment property.");\r
-    free (FileBuffer);\r
-    return EFI_ABORTED;\r
+  if (!AdjustInternalFfsPadding ((EFI_FFS_FILE_HEADER *) FileBuffer, FvImage,\r
+         1 << CurrentFileAlignment, &FileSize)) {\r
+    Status = AddPadFile (FvImage, 1 << CurrentFileAlignment, *VtfFileImage, NULL, FileSize);\r
+    if (EFI_ERROR (Status)) {\r
+      Error (NULL, 0, 4002, "Resource", "FV space is full, could not add pad file for data alignment property.");\r
+      free (FileBuffer);\r
+      return EFI_ABORTED;\r
+    }\r
   }\r
   //\r
   // Add file\r