kernel-adaptation-simplified

Device-agnostic RPM packaging for Halium kernel adaptations (SailfishOS). Builds the kernel, modules, boot.img and optionally vendor_boot.img/dtbo.img from a device spec that only defines macros.

Add it to a device repo as a submodule at kernel-adaptation-simplified/:

git submodule add https://github.com/HelloVolla/kernel-adaptation-simplified kernel-adaptation-simplified

Device repo layout

rpm/kernel-adaptation-<device>.spec   macros + %include of the .inc
linux/                                kernel source (submodule)
ramdisk-overlay/                      optional, appended to the unified boot ramdisk
halium-boot-ramdisk.img               optional, replaces the unified boot ramdisk
patches/apply-patches.sh + *.patch    optional, enabled with %apply_patches
overlay/vendor-ramdisk-overlay/       optional, for vendor_boot builds
<extra>_defconfig / *.config          config fragments referenced by the spec

Build, locally or from a CI workflow:

source kernel-adaptation-simplified/setup-env.sh
rpmbuild --build-in-place --define 'debug_package %{nil}' --bb rpm/kernel-adaptation-<device>.spec --buildroot=$PWD/buildroot

Spec macros

Required:

device                          device codename, e.g. halium-algiz
kernel_arch                     arm / arm64
makeopts                        e.g. LLVM=1 LLVM_IAS=1
kcflags                         e.g. "KCFLAGS="
clangtriple / crosscompile / crosscompile32 / hostldflags
defconfig                       make config target(s)
deviceinfo_dtb                  dtb path under boot/dts/
deviceinfo_kernel_cmdline
deviceinfo_bootimg_header_version
deviceinfo_bootimg_os_version / deviceinfo_bootimg_os_patch_level
deviceinfo_flash_pagesize + deviceinfo_flash_offset_* (header <= 2)
deviceinfo_flash_offset_dtb     header 2
Version / Release

Optional (with defaults):

rpm_device                      defaults to %{device}
kernel_config                   config make targets, defaults to %{defconfig}
kernel_image                    kernel binary name, defaults to Image.gz
ramdisk                         prebuilt boot ramdisk file, skips the unified one
ramdisk_directory               directory packed as the whole boot ramdisk, skips the unified one
bootimg_name                    name of the boot image installed into /boot, defaults to boot.img
source_directory                defaults to linux
device_target_cpu               forces the rpm target arch, e.g. aarch64
extra_config                    fragment copied into arch/<arch>/configs before make
apply_patches                   run patches/apply-patches.sh
build_Image / build_modules     default 1
build_dtboimage                 needs deviceinfo_dtbo
build_vendor_boot               header >= 3, needs overlay/vendor-ramdisk-overlay
devicetrees                     extra dtbs to install into /boot
deviceinfo_ramdisk_compression  gzip / lz4 (vendor_boot)
deviceinfo_kernel_disable_modules  skip modules in the vendor ramdisk
deviceinfo_flash_offset_second  defaults to 0x00000000
deviceinfo_bootimg_partition_size  adds the avb hash footer when set
deviceinfo_bootimg_append_vbmeta   defaults to false, appends ./vbmeta.img
deviceinfo_append_dtb           true appends the dtb to the kernel image (header 0/1)
deviceinfo_bootimg_prebuilt_dtb dtb file in the device repo used instead of deviceinfo_dtb
deviceinfo_bootimg_has_init_boot_partition  true puts the ramdisk into init_boot.img (header >= 3)
deviceinfo_init_boot_partition_size  defaults to 8388608
deviceinfo_bootimg_qcdt / deviceinfo_halium_version / deviceinfo_rootfs_image_sector_size  passed to mkvendorboot.sh
crossbuild                      OBS cross toolchain instead of makeopts/clang

Put device-specific build dependencies in the device spec. For example, a device that sets DTC_EXT=dtc in makeopts to use the host dtc instead of the one in the kernel tree needs BuildRequires: dtc in its own spec.

Boot images are signed with ./rsa4096_boot.pem from the device repo root when present.

Boot ramdisk

setup-env.sh downloads the unified halium boot ramdisk (the dynparts release of halium/initramfs-tools-halium) and exports it as HALIUM_RAMDISK. Device specific content stays in the device repo: a ramdisk-overlay/ directory is packed as cpio and appended to the unified ramdisk (recompressed to deviceinfo_ramdisk_compression when set), a committed halium-boot-ramdisk.img replaces the unified base entirely, and the ramdisk macro points at a fully prebuilt image. Devices that carry their whole initramfs as a directory set ramdisk_directory, which is packed as gzipped cpio and used as is.

Bundled tools

mkbootimg.py, mkdtboimg.py, avbtool (python2), mkvendorboot.sh and the GKI certification scripts under gki/. setup-env.sh fetches the android prebuilt toolchains and exports MKBOOTIMG_PATH/AVB_PATH; when those are not set the .inc falls back to the bundled copies.