arch/x86: drop special case cbfs locator

CBFS used to have a special region for the x86 bootblock, which also
contained a pointer to a CBFS master header, which describes the
layout of the CBFS.

Since we adopted other architectures, we got rid of the bootblock region
as a separate entity and add the x86 bootblock as a CBFS file now.

The master header still exists for compatibility with old cbfstool
versions, but it's neatly wrapped in either the bootblock file or in a
file carefully crafted at the right location (on all other architectures).

All the layout information we need is now available from FMAP, a core
part of a contemporary coreboot image, even on x86, so we can just use
the generic master header locator in src/lib/cbfs.c and get rid of the
special version.

Among the advantages: the x86 header locator reduced the size of the
CBFS by 64 bytes assuming that there's the bootblock region of at least
that size - this breaks assumptions elsewhere (eg. when walking CBFS in
cbfs_boot_locate() because the last file, the bootblock, will exceed the
CBFS region as seen by coreboot (since it's CBFS - 64bytes).

TEST=emulation/qemu-q35 still boots

Change-Id: I6fa78073ee4015d7769ed588dc67f9b019d42d07
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reported-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-on: https://review.coreboot.org/c/29801
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>
1 file changed
tree: 0b4343c68b9b5f1d9dcc323dd98c47383c342d8a
  1. .checkpatch.conf
  2. .clang-format
  3. .gitignore
  4. .gitmodules
  5. .gitreview
  6. 3rdparty/
  7. COPYING
  8. Documentation/
  9. MAINTAINERS
  10. Makefile
  11. Makefile.inc
  12. README.md
  13. configs/
  14. gnat.adc
  15. payloads/
  16. src/
  17. toolchain.inc
  18. util/
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:

  • doxygen (for generating/viewing documentation)
  • 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.