Added proper UEFI support. The ISO image can be 'burned' on USB flash drive (dd if=mll.iso of=/dev/xyz) and it works on UEFI systems (tested with QEMU and virtual hdd image). The 'hybrid' support also works and one ISO/hdd can be used on both firmware types.

src/.config

@@ -33,19 +33,23 @@ BUSYBOX_SOURCE_URL=http://busybox.net/downloads/busybox-1.27.2.tar.bz2
 #
 SYSLINUX_SOURCE_URL=http://kernel.org/pub/linux/utils/boot/syslinux/syslinux-6.03.tar.xz
 
+# You can find the latest 'systemd-boot' source bundles here:
+#
+#   http://github.com/ivandavidov/systemd-boot
+#
+SYSTEMD-BOOT_SOURCE_URL=https://github.com/ivandavidov/systemd-boot/releases/download/systemd-boot_10-Dec-2017/systemd-boot_10-Dec-2017.tar.xz
+
 ####################################################
 #                                                  #
 #  This section contains configuration properties  #
 #                                                  #
 ####################################################
 
-# This property is not used at the moment.
+# This property defines the firmware compatibility, i.e. on which systems MLL
-#
+# will be bootable.
-# This property defines the firmware compatibility. You can specify on what
-# systems MLL will be bootable.
 #
 #  bios - the generated ISO image will be compatible with legacy BIOS systems.
-#         This is the defaut option and it does not require root privileges
+#         This is the default option and it does not require root privileges.
 #
 #  uefi - the generated ISO image will be compatible with UEFI systems. This
 #         option requires root privileges.

src/02_build_kernel.sh

@@ -7,11 +7,6 @@ set -e
 
 echo "*** BUILD KERNEL BEGIN ***"
 
-# Prepare the kernel install area.
-echo "Removing old kernel artifacts. This may take a while."
-rm -rf $KERNEL_INSTALLED
-mkdir $KERNEL_INSTALLED
-
 # Change to the kernel source directory which ls finds, e.g. 'linux-4.4.6'.
 cd `ls -d $WORK_DIR/kernel/linux-*`
 
@@ -95,6 +90,11 @@ make \
   CFLAGS="$CFLAGS" \
   bzImage -j $NUM_JOBS
 
+# Prepare the kernel install area.
+echo "Removing old kernel artifacts. This may take a while."
+rm -rf $KERNEL_INSTALLED
+mkdir $KERNEL_INSTALLED
+
 # Install the kernel file.
 cp arch/x86/boot/bzImage \
   $KERNEL_INSTALLED/kernel

src/12_get_syslinux.sh

@@ -5,19 +5,44 @@ set -e
 # Load common properties and functions in the current script.
 . ./common.sh
 
+download() {
+  # Read the 'SYSLINUX_SOURCE_URL' property from '.config'.
+  DOWNLOAD_URL=`read_property SYSLINUX_SOURCE_URL`
+
+  # Grab everything after the last '/' character.
+  ARCHIVE_FILE=${DOWNLOAD_URL##*/}
+
+  # Download Syslinux source archive in the 'source' directory.
+  download_source $DOWNLOAD_URL $SOURCE_DIR/$ARCHIVE_FILE
+
+  # Extract the Syslinux sources in the 'work/syslinux' directory.
+  extract_source $SOURCE_DIR/$ARCHIVE_FILE syslinux
+}
+
 echo "*** GET SYSLINUX BEGIN ***"
 
-# Read the 'SYSLINUX_SOURCE_URL' property from '.config'.
+# Read the 'FIRMWARE_TYPE' property from '.config'.
-DOWNLOAD_URL=`read_property SYSLINUX_SOURCE_URL`
+FIRMWARE_TYPE=`read_property FIRMWARE_TYPE`
+echo "Firmware type is '$FIRMWARE_TYPE'."
 
-# Grab everything after the last '/' character.
+case $FIRMWARE_TYPE in
-ARCHIVE_FILE=${DOWNLOAD_URL##*/}
+  bios)
+    download
+    ;;
 
-# Download Syslinux source archive in the 'source' directory.
+  both)
-download_source $DOWNLOAD_URL $SOURCE_DIR/$ARCHIVE_FILE
+    download
+    ;;
 
-# Extract the Syslinux sources in the 'work/syslinux' directory.
+  uefi)
-extract_source $SOURCE_DIR/$ARCHIVE_FILE syslinux
+    echo "Syslinux download has been skipped."
+    ;;
+
+  *)
+    echo "Firmware type '$FIRMWARE_TYPE' is not recognized. Cannot continue."
+    ;;
+
+esac
 
 # We go back to the main MLL source folder.
 cd $SRC_DIR

src/12_get_systemd-boot.sh

@@ -0,0 +1,50 @@
+#!/bin/sh
+
+set -e
+
+# Load common properties and functions in the current script.
+. ./common.sh
+
+download() {
+  # Read the 'SYSTEMD-BOOT_SOURCE_URL' property from '.config'.
+  DOWNLOAD_URL=`read_property SYSTEMD-BOOT_SOURCE_URL`
+
+  # Grab everything after the last '/' character.
+  ARCHIVE_FILE=${DOWNLOAD_URL##*/}
+
+  # Download systemd-boot source archive in the 'source' directory.
+  download_source $DOWNLOAD_URL $SOURCE_DIR/$ARCHIVE_FILE
+
+  # Extract the 'systemd-boot' sources in the 'work/systemd-boot' directory.
+  extract_source $SOURCE_DIR/$ARCHIVE_FILE systemd-boot  
+}
+
+echo "*** GET SYSTEMD-BOOT BEGIN ***"
+
+# Read the 'FIRMWARE_TYPE' property from '.config'.
+FIRMWARE_TYPE=`read_property FIRMWARE_TYPE`
+echo "Firmware type is '$FIRMWARE_TYPE'."
+
+case $FIRMWARE_TYPE in
+  uefi)
+    download
+    ;;
+
+  both)
+    download
+    ;;
+
+  bios)
+    echo "'systemd-boot' download has been skipped."
+    ;;
+
+  *)
+    echo "Firmware type '$FIRMWARE_TYPE' is not recognized. Cannot continue."
+    ;;
+
+esac
+
+# We go back to the main MLL source folder.
+cd $SRC_DIR
+
+echo "*** GET SYSTEMD-BOOT END ***"

src/13_prepare_iso.sh

@@ -5,59 +5,201 @@ set -e
 # Load common properties and functions in the current script.
 . ./common.sh
 
-echo "*** PREPARE ISO BEGIN ***"
-
 # Find the Syslinux build directory.
 WORK_SYSLINUX_DIR=`ls -d $WORK_DIR/syslinux/syslinux-*`
 
-# Remove the old ISO generation area if it exists.
+init() {
-echo "Removing old ISO image work area. This may take a while."
+  # Remove the old ISO generation area if it exists.
-rm -rf $ISOIMAGE
+  echo "Removing old ISO image work area. This may take a while."
+  rm -rf $ISOIMAGE
 
-echo "Preparing new ISO image work area."
+  echo "Preparing new ISO image work area."
-mkdir -p $ISOIMAGE
+  mkdir -p $ISOIMAGE
+}
 
-# This is the folder where we keep legacy BIOS boot artifacts.
+prepare_mll_bios() {
-mkdir -p $ISOIMAGE/boot
+  # This is the folder where we keep legacy BIOS boot artifacts.
+  mkdir -p $ISOIMAGE/boot
 
-# Now we copy the kernel.
+  # Now we copy the kernel.
-cp $KERNEL_INSTALLED/kernel \
+  cp $KERNEL_INSTALLED/kernel \
     $ISOIMAGE/boot/kernel.xz
 
-# Now we copy the root file system.
+  # Now we copy the root file system.
-cp $WORK_DIR/rootfs.cpio.xz \
+  cp $WORK_DIR/rootfs.cpio.xz \
     $ISOIMAGE/boot/rootfs.xz
+}
 
-# Now we copy the overlay content if it exists
+prepare_overlay() {
-if [ -d $ISOIMAGE_OVERLAY \
+  # Now we copy the overlay content if it exists.
+  if [ -d $ISOIMAGE_OVERLAY \
     -a ! "`ls $ISOIMAGE_OVERLAY`" = "" ] ; then
 
     echo "The ISO image will have overlay structure."
     cp -r $ISOIMAGE_OVERLAY/* $ISOIMAGE
-else
+  else
     echo "The ISO image will have no overlay structure."
-fi
+  fi
+}
 
-# Add the Syslinux configuration files for legacy BIOS and additional
+prepare_boot_bios() {
-# UEFI startup script.
+  # Add the Syslinux configuration files for legacy BIOS and additional
-#
+  # UEFI startup script.
-# The existing UEFI startup script does not guarantee that you can run
+  #
-# MLL on UEFI systems. This script is invoked only in case your system
+  # The existing UEFI startup script does not guarantee that you can run
-# drops you in UEFI shell with support level 1 or above. See UEFI shell
+  # MLL on UEFI systems. This script is invoked only in case your system
-# specification 2.2, section 3.1. Depending on your system configuration
+  # drops you in UEFI shell with support level 1 or above. See UEFI shell
-# you may not end up with UEFI shell even if your system supports it.
+  # specification 2.2, section 3.1. Depending on your system configuration
-# In this case MLL will not boot and you will end up with some kind of
+  # you may not end up with UEFI shell even if your system supports it.
-# UEFI error message.
+  # In this case MLL will not boot and you will end up with some kind of
-cp -r $SRC_DIR/minimal_boot/bios/* \
+  # UEFI error message.
+  cp -r $SRC_DIR/minimal_boot/bios/* \
     $ISOIMAGE
 
-# Copy the precompiled files 'isolinux.bin' and 'ldlinux.c32'. These files
+  # Copy the precompiled files 'isolinux.bin' and 'ldlinux.c32'. These files
-# are used by Syslinux during the legacy BIOS boot process.
+  # are used by Syslinux during the legacy BIOS boot process.
-mkdir -p $ISOIMAGE/boot/syslinux
+  mkdir -p $ISOIMAGE/boot/syslinux
-cp $WORK_SYSLINUX_DIR/bios/core/isolinux.bin \
+  cp $WORK_SYSLINUX_DIR/bios/core/isolinux.bin \
     $ISOIMAGE/boot/syslinux
-cp $WORK_SYSLINUX_DIR/bios/com32/elflink/ldlinux/ldlinux.c32 \
+  cp $WORK_SYSLINUX_DIR/bios/com32/elflink/ldlinux/ldlinux.c32 \
     $ISOIMAGE/boot/syslinux
+}
+
+prepare_boot_uefi() {
+  # Find the build architecture based on the BusyBox executable.
+  BUSYBOX_ARCH=$(file $ROOTFS/bin/busybox | cut -d' ' -f3)
+
+  # Determine the proper UEFI configuration. The default image file
+  # names are described in UEFI specification 2.7, section 3.5.1.1.
+  # Note that the x86_64 UEFI image file name indeed contains small
+  # letter 'x'.
+  if [ "$BUSYBOX_ARCH" = "64-bit" ] ; then
+    MLL_CONF=x86_64
+    LOADER=$WORK_DIR/systemd-boot/systemd-boot*/uefi_root/EFI/BOOT/BOOTx64.EFI
+  else
+    MLL_CONF=x86
+    LOADER=$WORK_DIR/systemd-boot/systemd-boot*/uefi_root/EFI/BOOT/BOOTIA32.EFI
+  fi
+
+  # Find the kernel size in bytes.
+  kernel_size=`du -b $KERNEL_INSTALLED/kernel | awk '{print \$1}'`
+
+  # Find the initramfs size in bytes.
+  rootfs_size=`du -b $WORK_DIR/rootfs.cpio.xz | awk '{print \$1}'`
+
+  loader_size=`du -b $LOADER | awk '{print \$1}'`
+
+  # The EFI boot image is 64KB bigger than the kernel size.
+  image_size=$((kernel_size + rootfs_size + loader_size + 65536))
+
+  echo "Creating UEFI boot image file '$WORK_DIR/uefi.img'."
+  rm -f $WORK_DIR/uefi.img
+  truncate -s $image_size $WORK_DIR/uefi.img
+
+  echo "Attaching hard disk image file to loop device."
+  LOOP_DEVICE_HDD=$(losetup -f)
+  losetup $LOOP_DEVICE_HDD $WORK_DIR/uefi.img
+
+  echo "Formatting hard disk image with FAT filesystem."
+  mkfs.vfat $LOOP_DEVICE_HDD
+
+  echo "Preparing 'uefi' work area."
+  rm -rf $WORK_DIR/uefi
+  mkdir -p $WORK_DIR/uefi
+  mount $WORK_DIR/uefi.img $WORK_DIR/uefi
+
+#  # Add the configuration files for UEFI boot.
+#  cp -r $SRC_DIR/minimal_boot/uefi/* \
+#    $ISOIMAGE
+
+  echo "Preparing kernel and rootfs."
+  mkdir -p $WORK_DIR/uefi/minimal/$MLL_CONF
+  cp $KERNEL_INSTALLED/kernel \
+    $WORK_DIR/uefi/minimal/$MLL_CONF/kernel.xz
+  cp $WORK_DIR/rootfs.cpio.xz \
+    $WORK_DIR/uefi/minimal/$MLL_CONF/rootfs.xz
+
+  echo "Preparing 'systemd-boot' UEFI boot loader."
+  mkdir -p $WORK_DIR/uefi/EFI/BOOT
+  cp $LOADER \
+    $WORK_DIR/uefi/EFI/BOOT
+
+  echo "Preparing 'systemd-boot' configuration."
+  mkdir -p $WORK_DIR/uefi/loader/entries
+  cp $SRC_DIR/minimal_boot/uefi/loader/loader.conf \
+    $WORK_DIR/uefi/loader
+  cp $SRC_DIR/minimal_boot/uefi/loader/entries/mll-${MLL_CONF}.conf \
+    $WORK_DIR/uefi/loader/entries
+
+  echo "Setting the default UEFI boot entry."
+  sed -i "s|default.*|default mll-$MLL_CONF|" $WORK_DIR/uefi/loader/loader.conf
+
+  echo "Unmounting UEFI boot image file."
+  sync
+  umount $WORK_DIR/uefi
+  sync
+  sleep 1
+
+  # The directory is now empty (mount point for loop device).
+  rm -rf $WORK_DIR/uefi
+
+  # Make sure the UEFI boot image is readable.
+  chmod ugo+r $WORK_DIR/uefi.img
+
+  mkdir -p $ISOIMAGE/boot
+  cp $WORK_DIR/uefi.img \
+    $ISOIMAGE/boot
+}
+
+check_root() {
+  if [ ! "$(id -u)" = "0" ] ; then
+    cat << CEOF
+
+  ISO image preparation process for UEFI systems requires root permissions
+  but you don't have such permissions. Restart this script with root
+  permissions in order to generate UEFI compatible ISO structure.
+
+CEOF
+    exit 1
+  fi
+}
+
+echo "*** PREPARE ISO BEGIN ***"
+
+# Read the 'FIRMWARE_TYPE' property from '.config'
+FIRMWARE_TYPE=`read_property FIRMWARE_TYPE`
+echo "Firmware type is '$FIRMWARE_TYPE'."
+
+case $FIRMWARE_TYPE in
+  bios)
+    init
+    prepare_boot_bios
+    prepare_mll_bios
+    prepare_overlay
+    ;;
+
+  uefi)
+    check_root
+    init
+    prepare_boot_uefi
+    prepare_overlay
+    ;;
+
+  both)
+    check_root
+    init
+    prepare_boot_uefi
+    prepare_boot_bios
+    prepare_mll_bios
+    prepare_overlay
+    ;;
+
+  *)
+    echo "Firmware type '$FIRMWARE_TYPE' is not recognized. Cannot continue."
+    exit 1
+    ;;
+esac
+
 
 cd $SRC_DIR
 

src/14_generate_iso.sh

@@ -5,18 +5,29 @@ set -e
 # Load common properties and functions in the current script.
 . ./common.sh
 
-echo "*** GENERATE ISO BEGIN ***"
+# Generate ISO image for UEFI based systems.
+uefi() {
+  cd $ISOIMAGE
 
-if [ ! -d $ISOIMAGE ] ; then
+  # Now we generate 'hybrid' ISO image file which can also be used on
-  echo "Cannot locate ISO image work folder. Cannot continue."
+  # USB flash drive, e.g. 'dd if=minimal_linux_live.iso of=/dev/sdb'.
-  exit 1
+  xorriso -as mkisofs \
-fi
+    -isohybrid-mbr $WORK_DIR/syslinux/syslinux-*/bios/mbr/isohdpfx.bin \
+    -c boot.cat \
+    -e boot/uefi.img \
+      -no-emul-boot \
+      -isohybrid-gpt-basdat \
+    -o $SRC_DIR/minimal_linux_live.iso \
+    $ISOIMAGE
+}
 
-cd $ISOIMAGE
+# Generate ISO image for BIOS based systems.
+bios() {
+  cd $ISOIMAGE
 
-# Now we generate 'hybrid' ISO image file which can also be used on
+  # Now we generate 'hybrid' ISO image file which can also be used on
-# USB flash drive, e.g. 'dd if=minimal_linux_live.iso of=/dev/sdb'.
+  # USB flash drive, e.g. 'dd if=minimal_linux_live.iso of=/dev/sdb'.
-xorriso -as mkisofs \
+  xorriso -as mkisofs \
     -isohybrid-mbr $WORK_DIR/syslinux/syslinux-*/bios/mbr/isohdpfx.bin \
     -c boot/syslinux/boot.cat \
     -b boot/syslinux/isolinux.bin \
@@ -25,6 +36,56 @@ xorriso -as mkisofs \
       -boot-info-table \
     -o $SRC_DIR/minimal_linux_live.iso \
     $ISOIMAGE
+}
+
+# Generate ISO image for both BIOS and UEFI based systems.
+both() {
+  cd $ISOIMAGE
+
+  xorriso -as mkisofs \
+    -isohybrid-mbr $WORK_DIR/syslinux/syslinux-*/bios/mbr/isohdpfx.bin \
+    -c boot/syslinux/boot.cat \
+    -b boot/syslinux/isolinux.bin \
+      -no-emul-boot \
+      -boot-load-size 4 \
+      -boot-info-table \
+    -eltorito-alt-boot \
+    -e boot/uefi.img \
+      -no-emul-boot \
+      -isohybrid-gpt-basdat \
+    -o $SRC_DIR/minimal_linux_live.iso \
+  $ISOIMAGE
+}
+
+echo "*** GENERATE ISO BEGIN ***"
+
+if [ ! -d $ISOIMAGE ] ; then
+  echo "Cannot locate ISO image work folder. Cannot continue."
+  exit 1
+fi
+
+# Read the 'FIRMWARE_TYPE' property from '.config'
+FIRMWARE_TYPE=`read_property FIRMWARE_TYPE`
+echo "Firmware type is '$FIRMWARE_TYPE'."
+
+case $FIRMWARE_TYPE in
+  bios)
+    bios
+    ;;
+
+  uefi)
+    uefi
+    ;;
+
+  both)
+    both
+    ;;
+
+  *)
+    echo "Firmware type '$FIRMWARE_TYPE' is not recognized. Cannot continue."
+    exit 1
+    ;;
+esac
 
 cd $SRC_DIR
 

src/qemu-uefi.sh

@@ -0,0 +1,28 @@
+#!/bin/sh
+
+# Use this script without arguments to run the generated ISO image with QEMU.
+# If you pass '-hdd' or '-h' the virtual hard disk 'hdd.img' will be attached.
+# Note that this virtual hard disk has to be created in advance. You can use
+# the script 'generate_hdd.sh' to generate the hard disk image file. Once you
+# have hard disk image, you can use it as overlay device and persist all your
+# changes. See the '.config' file for more information on the overlay support.
+#
+# If you get kernel panic with message "No working init found", then try to
+# increase the RAM from 128M to 256M.
+
+# Location of the local file 'OVMF.fd' which is used as main firmware. You can
+# download it here:
+#
+#   https://sourceforge.net/projects/edk2/files/OVMF/
+#
+OVMF_LOCATION=~/Downloads/OVMF.fd
+
+cmd="qemu-system-$(uname -m) -pflash $OVMF_LOCATION -m 128M -cdrom minimal_linux_live.iso -boot d -vga std"
+
+if [ "$1" = "-hdd" -o "$1" = "-h" ] ; then
+  echo "Starting QEMU with attached ISO image and hard disk."
+  $cmd -hda hdd.img > /dev/null 2>&1 &
+else
+  echo "Starting QEMU with attached ISO image."
+  $cmd > /dev/null 2>&1 &
+fi