Brian Richardson edited this page Feb 26, 2017 · 4 revisions

Table of Contents

Frequently asked EDK II build questions

Regarding the Build for EDK II, how do you specify a different compiler tool chain on the command line?

Use –t parameter for the build command. Example: Using the Microsoft Visual Studio 2005 tool chain ...

    build –t VS2005

For using other tools see Getting_Started_with_EDK_II. This provides some detailed instructions for setting up some different tool chains? The file Conf/tools_def.txt contains a list of targets.

Is it possible to use PCDs @ build time?

It depends on what you are trying to do. For use in code, yes. For example Featureflag PCD type can be used. For determining if something should be built then it might be better to use the “Build –D MACRO-NAME” options.

Is there information on Building on Linux?

For EDK II, yes, the build tools will need to be recompiled for GCC. Link for how to Build for GCC:

What is the state of Python?

For Building EDK II Python of at least version 2.5 is needed. On Linux we've used 2.6 & 2.7. Python 3+ is not supported and will not work currently. On Windows, python is not required to be installed to build with EDK II. There is a Python interpreter that is part of the EFI toolkit on and is at the Python version level 2.4, There are long term plans to move to EDK II and support a later version of Python as part of the AppPkg. It is currently (01/2012) in Aplha stage.

What does the parsing tool do?

The parsing is part of the first stage of the build process. There are tools for parsing the set build description files and the target.txt for a package or platform and creates the intermediate make and autogen files

Regarding writing UEFI Applications in EDK II, where is the output and/or the binary UEFI application after doing a build?

The Build output directory is defined in the defines section of a .DSC file. For example, Nt32Pkg\Nt32Pkg.dsc - the UEFI application would be in Build\NT32\DEBUG_MYTOOLS\IA32

    OUTPUT_DIRECTORY   	        = Build/NT32

How do I get my UEFI application to the target UEFI System?

Copy the UEFI Binary image from the output directory after the build to a USB thumb drive. Insert the USB drive in the UEFI target system. Boot to the EFI Shell. The USB thumb drive should be one of the file systems, e.g. FS0:. Cd to that USB drive and run your UEFI application from the shell prompt

Is the Build tool source code part of the Build?

No, the repository for the Tool Source is a separate project. The binaries by default are for a Windows build machine. For building on a non Windows machine there are instructions for recompiling the build tools.

The sources are also in the BaseTools directory with the pre-build Windows executables. These sources are provided because they are the sources that were used to build the binaries. On Windows systems, the tools do not need to be built. The pre-build binaries can be used. One Linux, Unix, and OS/X systems, these sources are used to build the binaries for that OS, or in the case of Python, the Python sources are executed directly.

The BaseTools Source Project is where advanced development is done on the EDK II tools. Tool developers work in this separate project until a new feature is stable, and only once it is stable is a feature added to the BaseTools directory and new binaries are generated.

Can we use Ifdefs?

This is not recommended but can be used within the DSC or FDF as part of the build. But here is an example:

     MSFT:*_*_X64_GENFW_FLAGS  = --keepexceptiontable
     GCC:*_*_X64_GENFW_FLAGS   = --keepexceptiontable
     INTEL:*_*_X64_GENFW_FLAGS = --keepexceptiontable

When can the report generator show the protocols produced by modules?

The report generator can show protocols produced by modules. The Runtime DXE core will also report what is missing before handing off.

Why is the Buffer Security check flag (Build options) disabled for building EDK II UEFI applications and drivers but it is enabled for building tools.

UEFI applications and drivers are not executed in an Operating System environment. This is important, as the switches have very specific (and, in the pre-boot space, negative) impacts on generated code. The switch does two things in the code that are not acceptable for the pre-boot environment:

  • The switch enables additional code in the compiled code base, which requires a larger stack space than may be available in the pre-boot environment
  • The switch injects a call to a compiler specific function that is not present in our Firmware builds, and which we do not have information on how to emulate.
We disable these settings, as enabling them would create non-functioning code.

However, please be aware that Detecting Stack Overflows in Firmware is critical in validation and development, and we use other techniques in our code to do so. We just cannot generically support the /Gs flags (as noted above).

The tools do have this flag set, as they are used within the Operating System environment, where the intrinsic added by the compiler can be processed correctly.

Are there Dual-mode drivers in EDK II?

No. The EDK II build system does not support the dual mode drivers described in the PI Specification. These types of modules are very difficult to implement correctly, so we recommend that developer implement two different modules instead. The EDK II does allow them to share sources, but 2 different PE/COFF images would be generated when built.

Is there a tool to parse the BIOS Build tree?

a) Use the report generator build into the build tool “BUILD –Y” on the command line

                   	Flags that control the type of build report to
                        	generate.  Must be one of: [PCD, LIBRARY, FLASH, DEPEX, 
                        	To specify more than one flag, repeat this option on
                        	the command line and the default flag set is [PCD,
            Use “–Y DEPEX” and this will generate a text file with dependencies

b) Predicted dispatch order is limited because it makes assumptions about the behavior of the modules. It cannot handle that some PPI and DXE protocols that might be conditionally produced. Documented in the EDK2010 March 2010 release notes.

c) Behavior of dispatch – filter for DEBUG_DISPATCH in DSC in the PCD for the error level PcdDebugPrintErrorLevel

How does the build tool load the reset vector at 0xFFFFFFF0?

This is defined in the PI Specification, Volume 3.

In the FV (Firmware Volume) there is something called a Volume Top File inf the FV . A Volume Top File (VTF) is a file that must be located such that the last byte of the file is also the last byte of the firmware volume. Regardless of the file type, a VTF must have the file name GUID of EFI_FFS_VOLUME_TOP_FILE_GUID as defined below.

From a PI point of view the first module that runs is the SEC core. If you look at the VTF file it is basically the code that contains the reset vector, and it jumps to the SEC code.


So the hard code bit is the FV (Firmware Volume) that that contains the Volume Top File needs to start at an address where the end of the FV will end up at the magic reset vector address.

In general the EFI build system constructs relocatable PE/COFF images, and every image is linked at zero. If the code executes from FLASH, then when the FV is constructed the PE/COFF images that are XIP (eXecute In Place) have their PE/COFF image relocated based on where they end up in the FV (based on info in FDF file). This is done by the build system. If the EFI code runs from RAM then it is loaded by a PE/COFF loader and relocated to its load address.

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