EfiFs - EFI File System Drivers

This is a GPLv3+ implementation of standalone EFI File System drivers, based on the GRUB 2.0 read-only drivers.

For additional info as well as precompiled drivers, see https://efi.akeo.ie

Requirements

• Visual Studio 2019 (Windows) MinGW (Windows), gcc (Linux) or EDK2.
• A git client able to initialize/update submodules
• QEMU v2.7 or later if debugging with Visual Studio (NB: You can find QEMU Windows binaries here)

Compilation

Common

• Fetch the git submodules with

  git submodule init

  and

  git submodule update

  .
  NOTE This only works if you cloned the directory using

  git

  .
• Apply

  0001-GRUB-fixes.patch

  to the

  grub\

  subdirectory. This applies the changes that are required for successful compilation of GRUB.

Visual Studio (non EDK2)

• Open the solution file and hit

  F5

  to compile and debug the default driver.

gcc (non EDK2)

• Run

  make

  in the top directory. If needed you can also issue something like

  make ARCH= CROSS_COMPILE=

  where
  is one of

  ia32

  ,

  x64

  ,

  arm

  or

  aa64

  (the official UEFI abbreviations for an arch, as used in

  /efi/boot/boot[ARCH].efi

  ) and
  is the one for your cross- compiler, such as

  arm-linux-gnueabihf-

  . e.g.

  make ARCH=aa64 CROSS_COMPILE=aarch64-linux-gnu-

EDK2

• Open an elevated command prompt and create a symbolic link called

  EfiFsPkg

  , inside your EDK2 directory, to the EfiFs source. On Windows, from an elevated prompt, you could run something like

  mklink /D EfiFsPkg C:\efifs

  , and on Linux

  ln -s ../efifs EfiFsPkg

  .
• From a command prompt, set Grub to target the platform you are compiling for by invoking:
  • (Windows)

    set_grub_cpu.cmd 

  • (Linux)

    ./set_grub_cpu.sh 

    
    Where
    is one of

    ia32

    ,

    x64

    ,

    arm

    or

    aarch64

    .
    Note that you MUST invoke the

    set_grub_cpu

    script every time you switch target.
• After having invoked

  edksetup.bat

  (Windows) or

  edksetup.sh

  (Linux) run something like:
  

  build -a X64 -b RELEASE -t  -p EfiFsPkg/EfiFsPkg.dsc
  

  
  where
  is something like

  VS2015

  (Windows) or

  GCC5

  (Linux).
  NB: To build an individual driver, such as NTFS, you can also use something like:
  

  build -a X64 -b RELEASE -t  -p EfiFsPkg/EfiFsPkg.dsc -m EfiFsPkg/EfiFsPkg/Ntfs.inf
  

• Note that, provided that you cloned a recent EDK2 from git, you should be able to use

  VS2019

  as your EDK2 toolchain, including for buidling the ARM or ARM64 drivers, with something like:

  build -a AARCH64 -b RELEASE -t VS2019 -p EfiFsPkg/EfiFsPkg.dsc
  

• A Windows script to build the drivers, using EDK2 with VS2019 is also provided as

  edk2_build_drivers.cmd

  .

Testing

If QEMU is installed, the Visual Studio solution will set up and test the drivers using QEMU (by also downloading a sample image for each target file system). Note however that VS debugging expects a 64-bit version of QEMU to be installed in

C:\Program Files\qemu\

.msvc\debug.vbs

For testing outside of Visual Studio, make sure you have at least one disk with a target partition using the target filesystem, that is not being handled by other EFI filesystem drivers. Then boot into the EFI shell and run the following: *

load fs0:\_.efi

map -r

fs#

fs2:

FS_LOGGING

drivers

unload

Visual Studio 2019 and ARM/ARM64 support

Please be mindful that, to enable ARM/ARM64 compilation support in Visual Studio 2019, you MUST go to the Individual components screen in the setup application and select the ARM compilers and libraries there, as they do NOT appear in the default Workloads screen:

Additional Notes

This is a pure GPLv3+ implementation of EFI drivers. Great care was taken not to use any code from non GPLv3 compatible sources, such as rEFInd's

fsw_efi

Bonus: Commands to compile EfiFs using EDK2 on a vanilla Debian GNU/Linux 10.x

As root:

apt-get install nasm uuid-dev gcc-multilib gcc-aarch64-linux-gnu gcc-arm-linux-gnueabihf
cd /usr/src
git clone https://github.com/tianocore/edk2.git
git clone https://github.com/pbatard/efifs.git
cd efifs
git submodule update --init
cd grub
patch -Np1 -i ../0001-GRUB-fixes.patch
cd ../../edk2
git submodule update --init
ln -s ../efifs EfiFsPkg
make -C BaseTools
export GCC5_ARM_PREFIX=arm-linux-gnueabihf-
export GCC5_AARCH64_PREFIX=aarch64-linux-gnu-
source edksetup.sh --reconfig
./EfiFsPkg/set_grub_cpu.sh X64
build -a X64 -b RELEASE -t GCC5 -p EfiFsPkg/EfiFsPkg.dsc
./EfiFsPkg/set_grub_cpu.sh IA32
build -a IA32 -b RELEASE -t GCC5 -p EfiFsPkg/EfiFsPkg.dsc
./EfiFsPkg/set_grub_cpu.sh AARCH64
build -a AARCH64 -b RELEASE -t GCC5 -p EfiFsPkg/EfiFsPkg.dsc
./EfiFsPkg/set_grub_cpu.sh ARM
build -a ARM -b RELEASE -t GCC5 -p EfiFsPkg/EfiFsPkg.dsc