build: List all Kconfigs in CBFS `config` file, compress it

The coreboot build system automatically adds a `config` file to CBFS
that lists the exact Kconfig configuration that this image was built
with. This is useful to reproduce a build after the fact or to check
whether support for a specific feature is enabled in the image.

However, the file is currently generated using the `savedefconfig`
command to Kconfig, which generates the minimal .config file that is
needed to produce the required config in a coreboot build. This is fine
for reproduction, but bad when you want to check if a certain config was
enabled, since many configs get enabled by default or pulled in through
another config's `select` statement and thus don't show up in the
defconfig.

This patch tries to fix that second use case by instead including the
full .config instead. In order to save some space, we can remove all
comments (e.g. `# CONFIG_XXX is not set`) from the file, which still
makes it easy to test for a specific config (if it's in the file you can
extract the right value, if not you can assume it was set to `n`). We
can also LZMA compress it since this file is never read by firmware
itself and only intended for later re-extraction via cbfstool, which
always has LZMA support included.

On a sample Trogdor device the existing (uncompressed) `config` file
takes up 519 bytes in CBFS, whereas the new (compressed) file after this
patch will take up 1832 bytes -- still a small amount that should
hopefully not break the bank for anyone.

Signed-off-by: Julius Werner <jwerner@chromium.org>
Change-Id: I5259ec6f932cdc5780b8843f46dd476da9d19728
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69710
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
Reviewed-by: Jakub Czapiga <jacz@semihalf.com>
Reviewed-by: Martin Roth <martin.roth@amd.corp-partner.google.com>
2 files changed
tree: 40cbd8b878659f77bdc8e94e119dcd25f89e48b3
  1. 3rdparty/
  2. configs/
  3. Documentation/
  4. LICENSES/
  5. payloads/
  6. spd/
  7. src/
  8. tests/
  9. util/
  10. .checkpatch.conf
  11. .clang-format
  12. .editorconfig
  13. .gitignore
  14. .gitmodules
  15. .gitreview
  16. .mailmap
  17. AUTHORS
  18. COPYING
  19. gnat.adc
  20. MAINTAINERS
  21. Makefile
  22. Makefile.inc
  23. README.md
  24. toolchain.inc
README.md

coreboot README

coreboot is a Free Software project aimed at replacing the proprietary BIOS (firmware) found in most computers. coreboot performs a little bit of hardware initialization and then executes additional boot logic, called a payload.

With the separation of hardware initialization and later boot logic, coreboot can scale from specialized applications that run directly firmware, run operating systems in flash, load custom bootloaders, or implement firmware standards, like PC BIOS services or UEFI. This allows for systems to only include the features necessary in the target application, reducing the amount of code and flash space required.

coreboot was formerly known as LinuxBIOS.

Payloads

After the basic initialization of the hardware has been performed, any desired "payload" can be started by coreboot.

See https://www.coreboot.org/Payloads for a list of supported payloads.

Supported Hardware

coreboot supports a wide range of chipsets, devices, and mainboards.

For details please consult:

Build Requirements

  • make
  • gcc / g++ Because Linux distribution compilers tend to use lots of patches. coreboot does lots of "unusual" things in its build system, some of which break due to those patches, sometimes by gcc aborting, sometimes - and that's worse - by generating broken object code. Two options: use our toolchain (eg. make crosstools-i386) or enable the ANY_TOOLCHAIN Kconfig option if you're feeling lucky (no support in this case).
  • iasl (for targets with ACPI support)
  • pkg-config
  • libssl-dev (openssl)

Optional:

  • gdb (for better debugging facilities on some targets)
  • ncurses (for make menuconfig and make nconfig)
  • flex and bison (for regenerating parsers)

Building coreboot

Please consult https://www.coreboot.org/Build_HOWTO for details.

Testing coreboot Without Modifying Your Hardware

If you want to test coreboot without any risks before you really decide to use it on your hardware, you can use the QEMU system emulator to run coreboot virtually in QEMU.

Please see https://www.coreboot.org/QEMU for details.

Website and Mailing List

Further details on the project, a FAQ, many HOWTOs, news, development guidelines and more can be found on the coreboot website:

https://www.coreboot.org

You can contact us directly on the coreboot mailing list:

https://www.coreboot.org/Mailinglist

Copyright and License

The copyright on coreboot is owned by quite a large number of individual developers and companies. Please check the individual source files for details.

coreboot is licensed under the terms of the GNU General Public License (GPL). Some files are licensed under the "GPL (version 2, or any later version)", and some files are licensed under the "GPL, version 2". For some parts, which were derived from other projects, other (GPL-compatible) licenses may apply. Please check the individual source files for details.

This makes the resulting coreboot images licensed under the GPL, version 2.