# Maintainer: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
# s390x Port Maintainer: Josephine Pfeiffer <josie@redhat.com>

pkgbase=linux-s390x
pkgver=6.18.6
pkgrel=1
pkgdesc='Linux (s390x mainframe port)'
url='https://github.com/archlinux/linux'
arch=(x86_64)  # Build host architecture
_target_arch=s390x
license=(GPL-2.0-only)
makedepends=(
  bc
  cpio
  gettext
  libelf
  pahole
  perl
  python
  tar
  xz
  # Cross-compilation tools
  s390x-linux-gnu-gcc
  s390x-linux-gnu-binutils
)
options=(
  !debug
  !strip
)
_srcname=linux-${pkgver%.*}
_srctag=v${pkgver}-arch1
source=(
  https://cdn.kernel.org/pub/linux/kernel/v${pkgver%%.*}.x/${_srcname}.tar.{xz,sign}
  $url/releases/download/$_srctag/linux-$_srctag.patch.zst{,.sig}
  config-s390x  # s390x specific kernel config
)
validpgpkeys=(
  ABAF11C65A2970B130ABE3C479BE3E4300411886  # Linus Torvalds
  647F28654894E3BD457199BE38DBBDC86092693E  # Greg Kroah-Hartman
  83BC8889351B5DEBBB68416EB8AC08600F108CDF  # Jan Alexander Steffens (heftig)
)
# Updated checksums will be needed after creating config-s390x
sha256sums=('SKIP'
            'SKIP'
            'SKIP'
            'SKIP'
            'SKIP')

export KBUILD_BUILD_HOST=archlinux
export KBUILD_BUILD_USER=$pkgbase
export KBUILD_BUILD_TIMESTAMP="$(date -Ru${SOURCE_DATE_EPOCH:+d @$SOURCE_DATE_EPOCH})"

# Cross-compilation environment
export ARCH=s390
export CROSS_COMPILE=s390x-linux-gnu-

prepare() {
  cd $_srcname

  echo "Setting version..."
  echo "-$pkgrel" > localversion.10-pkgrel
  echo "${pkgbase#linux}" > localversion.20-pkgname

  local src
  for src in "${source[@]}"; do
    src="${src%%::*}"
    src="${src##*/}"
    src="${src%.zst}"
    [[ $src = *.patch ]] || continue
    echo "Applying patch $src..."
    patch -Np1 < "../$src"
  done

  echo "Setting config for s390x..."
  cp ../config-s390x .config
  make olddefconfig
  diff -u ../config-s390x .config || :

  make -s kernelrelease > version
  echo "Prepared $pkgbase version $(<version)"
}

build() {
  cd $_srcname
  
  # Build kernel for s390x
  make -j$(nproc) bzImage modules
  
  # Note: htmldocs and bpftool builds are skipped for cross-compilation
}

_package() {
  pkgdesc="The $pkgdesc kernel and modules"
  depends=(
    coreutils
    initramfs
    kmod
  )
  optdepends=(
    'linux-firmware: firmware images needed for some devices'
  )
  provides=(
    WIREGUARD-MODULE
  )

  cd $_srcname
  local modulesdir="$pkgdir/usr/lib/modules/$(<version)"

  echo "Installing boot image..."
  # For s390x, the kernel image is arch/s390/boot/bzImage
  install -Dm644 "arch/s390/boot/bzImage" "$modulesdir/vmlinuz"

  # Used by mkinitcpio to name the kernel
  echo "$pkgbase" | install -Dm644 /dev/stdin "$modulesdir/pkgbase"

  echo "Installing modules..."
  ZSTD_CLEVEL=19 make INSTALL_MOD_PATH="$pkgdir/usr" INSTALL_MOD_STRIP=1 \
    DEPMOD=/doesnt/exist modules_install  # Suppress depmod

  # remove build link
  rm "$modulesdir"/build
}

_package-headers() {
  pkgdesc="Headers and scripts for building modules for the $pkgdesc kernel"
  depends=(pahole)

  cd $_srcname
  local builddir="$pkgdir/usr/lib/modules/$(<version)/build"

  echo "Installing build files..."
  install -Dt "$builddir" -m644 .config Makefile Module.symvers System.map \
    localversion.* version vmlinux
  install -Dt "$builddir/kernel" -m644 kernel/Makefile
  install -Dt "$builddir/arch/s390" -m644 arch/s390/Makefile
  cp -t "$builddir" -a scripts

  # s390x doesn't use objtool
  # install -Dt "$builddir/tools/objtool" tools/objtool/objtool

  echo "Installing headers..."
  cp -t "$builddir" -a include
  cp -t "$builddir/arch/s390" -a arch/s390/include
  install -Dt "$builddir/arch/s390/kernel" -m644 arch/s390/kernel/asm-offsets.s

  install -Dt "$builddir/drivers/md" -m644 drivers/md/*.h
  install -Dt "$builddir/net/mac80211" -m644 net/mac80211/*.h

  echo "Installing KConfig files..."
  find . -name 'Kconfig*' -exec install -Dm644 {} "$builddir/{}" \;

  echo "Removing unneeded architectures..."
  local arch
  for arch in "$builddir"/arch/*/; do
    [[ $arch = */s390/ ]] && continue
    echo "Removing $(basename "$arch")"
    rm -r "$arch"
  done

  echo "Removing documentation..."
  rm -r "$builddir/Documentation"

  echo "Removing broken symlinks..."
  find -L "$builddir" -type l -printf 'Removing %P\n' -delete

  echo "Removing loose objects..."
  find "$builddir" -type f -name '*.o' -printf 'Removing %P\n' -delete

  echo "Stripping build tools..."
  local file
  while read -rd '' file; do
    case "$(file -Sib "$file")" in
      application/x-sharedlib\;*)      # Libraries (.so)
        strip -v $STRIP_SHARED "$file" ;;
      application/x-archive\;*)        # Libraries (.a)
        strip -v $STRIP_STATIC "$file" ;;
      application/x-executable\;*)     # Binaries
        strip -v $STRIP_BINARIES "$file" ;;
      application/x-pie-executable\;*) # Relocatable binaries
        strip -v $STRIP_SHARED "$file" ;;
    esac
  done < <(find "$builddir" -type f -perm -u+x ! -name vmlinux -print0)

  echo "Stripping vmlinux..."
  strip -v $STRIP_STATIC "$builddir/vmlinux"

  echo "Adding symlink..."
  mkdir -p "$pkgdir/usr/src"
  ln -sr "$builddir" "$pkgdir/usr/src/$pkgbase"
}

pkgname=(
  "$pkgbase"
  "$pkgbase-headers"
)
for _p in "${pkgname[@]}"; do
  eval "package_$_p() {
    $(declare -f "_package${_p#$pkgbase}")
    _package${_p#$pkgbase}
  }"
done

# vim:set ts=8 sts=2 sw=2 et: