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asm asm: Fix up assembly for clang May 4, 2018
ccan build: use thin archives rather than incremental linking Mar 1, 2018
core cpu: Better output when waiting for a very long job Aug 16, 2018
doc skiboot 6.0.8 release notes Aug 16, 2018
external don't fail fatally if qtrace can't be loaded Aug 15, 2018
hdata Fixup unit tests for cpu_queue_job() in mem_region.c Jul 18, 2018
hw phb4: Disable 32-bit MSI in capi mode Aug 16, 2018
include lock: Fix interactions between lock dependency checker and stack checker Aug 16, 2018
libc Fix strtok for previous tokens being NULL May 24, 2018
libfdt build: use thin archives rather than incremental linking Mar 1, 2018
libflash libflash: quieten our logging Jun 19, 2018
libpore STOP API: API conditionally supports 255 SCOM restore entries for eac… Jul 19, 2018
libstb Recognise signed VERSION partition Jul 17, 2018
libxz build: use thin archives rather than incremental linking Mar 1, 2018
opal-ci test/qemu: start building qemu again, and use our built qemu for tests Jun 27, 2018
platforms lpc: Silence LPC SYNC no-response error when necessary Jul 17, 2018
test test/qemu: start building qemu again, and use our built qemu for tests Jun 27, 2018
.gitignore gitignore: Add stb test kernel files Apr 9, 2018
.travis.yml travis: remove Ubuntu 12.04 May 29, 2018
CONTRIBUTING.md doc: Further document development and release process May 22, 2018
LICENCE Initial commit of Open Source release Jul 2, 2014
Makefile Makefile: Fix building natively on ppc64le May 9, 2018
Makefile.main Makefile: remove try-cflags on no-altivec and no-vsx Jul 26, 2018
Makefile.rules build: use thin archives rather than incremental linking Mar 1, 2018
README.md README: document output files Mar 1, 2018
coverity-model.c lock: Add additional lock auditing code Dec 21, 2017
extract-gcov.c gcov: Another GCC, another gcov tweak Mar 8, 2018
make_offsets.sh Fix asm-offsets generation May 4, 2018
make_version.sh make_version: Fix check for '.version' file Nov 22, 2017
skiboot.lds.S Keep constructors with priorities Mar 8, 2018
skiboot.spec skiboot.spec: Update to v5.10 release Mar 2, 2018



Firmware for OpenPower systems.

Source: https://github.com/open-power/skiboot

Mailing list: skiboot@lists.ozlabs.org

Info/subscribe: https://lists.ozlabs.org/listinfo/skiboot

Archives: https://lists.ozlabs.org/pipermail/skiboot/

Patchwork: http://patchwork.ozlabs.org/project/skiboot/list/


OPAL firmware (OpenPower Abstraction Layer) comes in several parts.

A simplified flow of what happens when the power button is pressed is:

  1. The baseboard management controller (BMC) powers the system on.
  2. The BMC selects the master chip and releases the self-boot engines (SBEs) on the POWER8 chips, master last.
  3. The BMC relinquishes control of the flexible service interface (FSI) SCAN/SCOM engines.
  4. The hostboot firmware IPLs the system. It initiates a secondary power-on sequence through a digital power systems sweep (DPSS).
  5. The hostboot firmware loads the OPAL image and moves all processors to their execution starting points.

Here, the OPAL image is three parts:

  1. skiboot (includes OPAL runtime services)
  2. skiroot - the bootloader environment
    • kernel
    • initramfs (containing petitboot bootloader)

They may be all part of one payload or three separate images (depending on platform).

The bootloader will kexec a host kernel (probably linux). The host OS can make OPAL calls. The OPAL API is documented in doc/opal-api/ (there are missing parts, patches are welcome!)

See doc/overview.rst for a more in depth overview of skiboot.


Any host OS can build and test skiboot provided it has a C cross compiler for big endian powerpc64. All good Linux distributions (and several bad ones) provide a packaged compiler that can be installed through the usual package management tools.

To build on Ubuntu:

apt-get install gcc-powerpc64le-linux-gnu gcc valgrind \
	expect libssl-dev device-tree-compiler make \
CROSS=powerpc64le-linux-gnu- make -j`nproc`

To build on Fedora:

dnf install gcc-powerpc64le-linux-gnu binutils-powerpc64-linux-gnu gcc make \
    diffutils findutils expect valgrind-devel dtc openssl-devel xz
CROSS=powerpc64le-linux-gnu- make -j`nproc`

(The little-endian powerpc64le compilers in Ubuntu and Fedora are actually bi-endian and can compile skiboot even though it's big-endian. We recommend installing a little-endian toolchain if you plan on building other projects.)

On any POWER system with a bi-endian system compiler:

CROSS="" make -j`nproc`

Alternatively, pre-built cross compilers for x86 systems can be downloaded from here: https://www.kernel.org/pub/tools/crosstool/ When using these compilers add /opt/cross/gcc-4.8.0-nolibc/powerpc64-linux/bin/ to your PATH. Once this is done skiboot can be compiler by just running make


Skiboot comes with a set of unit tests that can be run on your desktop. They can can be run with:

make check

To test in a simulator, install the IBM POWER8 Functional Simulator from: http://www-304.ibm.com/support/customercare/sas/f/pwrfs/home.html Also see external/mambo/README.md

Qemu (as of 2.2.0) is not suitable as it does not (yet) implement the HyperVisor mode of the POWER8 processor. See https://www.flamingspork.com/blog/2015/08/28/running-opal-in-qemu-the-powernv-platform/ for instructions on how to use a work-in-progress patchset to qemu that may be suitable for some work.

To run a boot-to-bootloader test, you'll need a zImage.papr built using the mambo_defconfig config for op-build. See https://github.com/open-power/op-build/ on howto build. Drop zImage.epapr in the skiboot directory and the skiboot test suite will automatically pick it up.

See opal-ci/README for further testing instructions.

To test on real hardware, you will need to understand how to flash new skiboot onto your system. This will vary from platform to platform.

You may want to start with external/boot-tests/boot_test.sh as it can (provided the correct usernames/passwords) automatically flash a new skiboot onto ASTBMC based OpenPower machines.


All patches should be sent to the mailing list with linux-kernel style 'Signed-Off-By'. The following git commands are your friends:

git commit -s
git format-patch

You probably want to read the linux https://kernel.org/doc/html/latest/process/submitting-patches.html as much of it applies to skiboot.

Output files

The Skiboot build process produces a bunch of different outputs. This is what they are, and where you should use them:

skiboot.elf: The output of the linker. Don't flash to a system, but useful when debugging

skiboot.lid: The raw binary object, named .lid because IBM. Flash this on really old P8 systems, the POWER Functional Simulator (mambo), or FSP systems

skiboot.lid.stb: Lid wrapped with secure boot header. Use on FSP systems

skiboot.lid.xz: Compressed raw binary. Use this on a OpenPower P8

skiboot.lid.xz.stb: Compressed raw binary wrapped with a secure boot header. Use this on OpenPower P9 systems