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 1.x

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
• 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.

License

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