4.5 Post-Build Stage

4.5.1 Assemble FLASH Images - ImageGen stage

Once all the modules' EFI image files have been created, the final stage of a build process is called. For FLASH images, this stage uses the FDF file, and some parts of the DSC file to create the final binary image files. This stage processes the individual EFI files, formatting them into leaf EFI_SECTION types and combining them using implied rules (or custom rules) into different firmware files (FFS), firmware volumes (FVs) and the final FLASH images (FDs). The construction of these images is based on the content of the FDF file (with a very limited amount of data being obtained from the DSC file).

A binary file with a file type of DISPOSABLE will not be placed into a EFI_SECTION_DISPOSABLE encapsulation section. This keyword is used by UEFI Packaging Tool to ensure that files, such as debug symbol files, get packaged correctly.

The default build rules specify removal of .reloc sections of the PE32/PE32+ file for all SEC, PEI_CORE and PEIM modules and components. To prevent removal of the .reloc section, a module developer will need to specify a keyword, SHADOW in the INF file.

Assuming that all FD and FV images are going to be generated (based on the default value of the top-level build command), for each FV image specified the following must occur.

1. The FDF file is parsed to create a directed graph structure for each FV image, so that all leaf EFI sections are created first. During this stage, INF files that contain a [Binaries] section and that do not contain a [Sources] section will be processed. An INF file that contains a [Binaries] section that contains an entry that starts with DISPOSABLE, that entry must be ignored - these files are not to be placed into an EFI_SECTION_DISPOSABLE encapsulation section.

2. If an INF not listed in the DSC file, but is listed in the FDF file and the INF contains a [PatchPcd] section, the tools must test to determine if the PCD is listed in the DSC (or FDF) file, and whether the value listed in the DSC (or FDF) file is different from the value in the INF file. If the value is different, the tools must patch the binary .efi file with the value from the FDF or DSC file prior to creating the EFI leaf section.

3. The tools are also responsible for creating binary files containing all DynamicEx PCDs that are listed in the DSC, FDF and Binary INF files (listed in the FDF file). These binaries are automatically placed into the (PEIM and DXE) PCD driver FFS files.

4. These leaf sections are either put into encapsulated sections or put directly into an FFS file following the implied rules (or user defined rules) defined later in this document.

5. As each FFS File is created, the file is either encapsulated into another FFS file or appended to an FV image.

6. Once all of the FFS files have been placed into an FV image file, the FV file is put into an FD file at the location specified by the FD section of the FDF file.

4.5.2 EFI PCI Expansion Option ROM Images

There are two methods for creating an option ROM image, when the FDF file is specified and when an FDF file is not present. To build from source and no FDF file is present, if the module's INF file contains the keywords, PCI_DEVICE_ID, PCI_VENDOR_ID and PCI_CLASS_CODE, the build will terminate after creating EFI files - there will be no call to the GenFds tool. These key words also force the creation of an option ROM image, after the EFI files have been created, using the EfiRom program to create the EFI PCI Expansion ROM image. If an FDF is present, then the build tools will parse the FDF file looking for an [OptionRom] section, and create the option ROM based on the contents of this section. Note that the FDF specification permits adding binary images, such as the legacy option rom binary, as well as support for multiple architecture driver images to the option ROM image.

A binary flag, PCI_COMPRESS, when set to true, tells the tools to use EFI standard compression to compress the entire option ROM image.

Option ROM images are always created in the output FV directory.

4.5.3 UEFI Applications

When building only UEFI applications, no FDF file is specified in the DSC file; the build would normal terminate after creating EFI files - there would be no call to the GenFds tool. Using an option on the build tool command line to specify building a UEFI Application forces the parsing stage to generate the module's Makefile with an alternate path. This path will force the creation of a UEFI application, after the EFI files have been created, using UEFI application specific arguments for the GenFds tool.