152 lines
5.1 KiB
Markdown
152 lines
5.1 KiB
Markdown
# skiboot
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Firmware for OpenPower systems.
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Source: https://github.com/open-power/skiboot
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Mailing list: skiboot@lists.ozlabs.org
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Info/subscribe: https://lists.ozlabs.org/listinfo/skiboot
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Archives: https://lists.ozlabs.org/pipermail/skiboot/
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Patchwork: http://patchwork.ozlabs.org/project/skiboot/list/
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## Overview
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OPAL firmware (OpenPower Abstraction Layer) comes in several parts.
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A simplified flow of what happens when the power button is pressed is:
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1. The baseboard management controller (BMC) powers the system on.
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2. The BMC selects the master chip and releases the self-boot engines (SBEs)
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on the POWER8 chips, master last.
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3. The BMC relinquishes control of the flexible service interface (FSI)
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SCAN/SCOM engines.
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4. The hostboot firmware IPLs the system. It initiates a secondary power-on
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sequence through a digital power systems sweep (DPSS).
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5. The hostboot firmware loads the OPAL image and moves all processors to
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their execution starting points.
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Here, the OPAL image is three parts:
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1. skiboot (includes OPAL runtime services)
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2. skiroot - the bootloader environment
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* kernel
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* initramfs (containing petitboot bootloader)
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They may be all part of one payload or three separate images (depending on
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platform).
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The bootloader will kexec a host kernel (probably linux). The host OS can
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make OPAL calls. The OPAL API is documented in doc/opal-api/ (there are
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missing parts, patches are welcome!)
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See doc/overview.rst for a more in depth overview of skiboot.
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## Building
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Any host OS can build and test skiboot provided it has a C cross compiler
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for *big endian* powerpc64. All good Linux distributions (and several bad
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ones) provide a packaged compiler that can be installed through the usual
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package management tools.
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To build on Ubuntu:
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```
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apt-get install gcc-powerpc64le-linux-gnu gcc valgrind \
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expect libssl-dev device-tree-compiler make \
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xz-utils
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CROSS=powerpc64le-linux-gnu- make -j`nproc`
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```
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To build on Fedora:
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```
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dnf install gcc-powerpc64le-linux-gnu binutils-powerpc64-linux-gnu gcc make \
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diffutils findutils expect valgrind-devel dtc openssl-devel xz
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CROSS=powerpc64le-linux-gnu- make -j`nproc`
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```
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(The little-endian powerpc64le compilers in Ubuntu and Fedora are actually
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bi-endian and can compile skiboot even though it's big-endian. We recommend
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installing a little-endian toolchain if you plan on building other projects.)
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On any POWER system with a bi-endian system compiler:
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```
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CROSS="" make -j`nproc`
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```
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Alternatively, pre-built cross compilers for x86 systems can be downloaded
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from here: https://www.kernel.org/pub/tools/crosstool/ When using
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these compilers add /opt/cross/gcc-4.8.0-nolibc/powerpc64-linux/bin/
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to your PATH. Once this is done skiboot can be compiler by just running `make`
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## Testing
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Skiboot comes with a set of unit tests that can be run on your desktop.
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They can can be run with:
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```
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make check
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```
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To test in a simulator, install the IBM POWER8 Functional Simulator from:
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http://www-304.ibm.com/support/customercare/sas/f/pwrfs/home.html
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Also see external/mambo/README.md
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Qemu as of version 2.8 implements the 'powernv' machine model and is sufficient
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to run skiboot:
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qemu-system-ppc64 -M powernv -m 3G -nographic -L /path/to/skiboot/
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To run a boot-to-bootloader test you need a Linux kernel image 'zImage.epapr'.
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Build one using the `opal_defconfig` config for op-build. See
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https://github.com/open-power/op-build/ on how to build, or download one from
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https://openpower.xyz/job/openpower/job/openpower-op-build/.
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Drop zImage.epapr in the skiboot directory and the skiboot test suite will
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automatically pick it up. You can also run a combined skiboot and Linux test in
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Qemu (version 3.0+):
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qemu-system-ppc64 -M powernv -m 3G -nographic -kernel zImage.epapr -L /path/to/skiboot/
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See opal-ci/README for further testing instructions.
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To test on real hardware, you will need to understand how to flash new
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skiboot onto your system. This will vary from platform to platform.
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You may want to start with external/boot-tests/boot_test.sh as it can
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(provided the correct usernames/passwords) automatically flash a new
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skiboot onto ASTBMC based OpenPower machines.
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## Hacking
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All patches should be sent to the mailing list with linux-kernel style
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'Signed-Off-By'. The following git commands are your friends:
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```
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git commit -s
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git format-patch
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```
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You probably want to read the linux
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https://kernel.org/doc/html/latest/process/submitting-patches.html as
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much of it applies to skiboot.
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## Output files
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The Skiboot build process produces a bunch of different outputs. This is what
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they are, and where you should use them:
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skiboot.elf: The output of the linker. Don't flash to a system, but useful when debugging
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skiboot.lid: The raw binary object, named .lid because IBM. Flash this on
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really old P8 systems, the POWER Functional Simulator (mambo), or
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FSP systems
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skiboot.lid.stb: Lid wrapped with secure boot header. Use on FSP systems
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skiboot.lid.xz: Compressed raw binary. Use this on a OpenPower P8
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skiboot.lid.xz.stb: Compressed raw binary wrapped with a secure boot header.
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Use this on OpenPower P9 systems
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## License
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See LICENSE
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