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OSF Builder

This osf-builder repo is an open source repo to faciliate the development community to collaborate on Open System Firmware (OSF).

Build pre-requisites

  • GNU make
  • Go version needs to be >=1.19. for u-root compatibility after v0.10.0

Build process

OSF boot starts with coreboot first, then Linux kernel which then executes init, which in this case is provided by u-root.

OSF build also consists of these three stages, executed in the reverse order.

Entire build requires PLATFORM to be defined, this specifies the platform for which build is being run.

  • getdeps is a tool used to fetch dependencies. It can clone Git repos, fetch files, etc.
    • It is configured by a JSON file that must be specified in CONFIG.
    • CONFIG consists of three top-level sections: initramfs, kernel and coreboot that specify what to fetch for each of the stages.
  • Initramfs image is built first, by building u-root with certain set of commands.
    • initramfs section of the CONFIG is executed by getdeps to fetch the u-root sources and the Go toolchain.
    • PATCHES_DIR/initramfs-PLATFORM-* patches are applied.
    • Default set of commands can be found in Makefile.inc UROOT_BASE_CMDS, it can be augmented with UROOT_ADDITIONAL_CMDS or replaced entirely.
    • Additional commands can come from u-root itself or from external packages, in which case UROOT_ADDITIONAL_GOPATH may be required.
    • Initramfs can embed binary utilities, files can be added through UROOT_ADDITIONAL_FILES as local_path:initramfs_path pairs.
  • Kernel is built next
    • kernel section of the CONFIG is executed by getdeps to fetch the kernel source.
    • PATCHES_DIR/kernel-PLATFORM-* patches are applied.
    • KERNEL_CONFIG is used as .config.
  • Coreboot is built last
    • coreboot section of the CONFIG is executed by getdeps to fetch the source and toolchain dependencies.
    • PATCHES_DIR/coreboot-PLATFORM-* patches are applied.
    • COREBOOT_CONFIG is used as .config.
    • Resulting flahs image is written to osf-PLATFORM.rom in the current directory.

How to build the sample project

  • Clone the repo.
  • cd examples/qemu-x86_64
  • Run make
  • Once the build is completed, run make run, it will start a VM with the OSF BIOS image.

Development tricks

  • To speed up builds, when not actively working on initramfs or the kernel, pass ALWAYS_BUILD_INITRAMFS=0 and ALWAYS_BUILD_KERNEL=0 respectively.
    • make ALWAYS_BUILD_INITRAMFS=0 ALWAYS_BUILD_KERNEL=0 - for hacking on coreboot only.
  • make clean will clean all the components without wiping the work done by getdeps.
    • make clean-coreboot and make clean-kernel will clean just the coreboot and kernel components.
  • make wipe will wipe everything, including downloaded deps.
    • make wipe-coreboot and make wipe-kernel will clean just the coreboot and kernel components.
    • Note that toolchain cache survives wipe and will be used in the next build.
  • make kernel will only build LinuxBoot payload.
  • You can place a shell script vpd.sh under your project folder which would be executed for your customized actions such as setting your VPD key-value pairs to your coreboot image.
  • When the json configuration files' mtime is changed, osf-builder would trigger a full wipe of your downloaded coreboot, u-root and kernel code. To avoid this you can update the mtime of all the $(PLATFORM_BUILD_DIR)/.*-deps, for exmaple
    • cd build/qemu-x86_64 and touch .*-deps will update the mtime of .*-deps files.

License

OSF Builder is MIT licensed, as found in the LICENSE file.