util/cbfstool: Treat region offsets differently than absolute addresses

cbfstool overloads baseaddress to represent multiple things:
1. Address in SPI flash space
2. Address in host space (for x86 platforms)
3. Offset from end of region (accepted as negative number)

This was done so that the different functions that use these
addresses/offsets don't need to be aware of what the value represents
and can use the helper functions convert_to_from* to get the required
values.

Thus, even if the user provides a negative value to represent offset
from end of region, it was stored as an unsigned integer. There are
special checks in convert_to_from_top_aligned which guesses if the
value provided is really an offset from the end of region and converts
it to an offset from start of region.

This has worked okay until now for x86 platforms because there is a
single fixed decode window mapping the SPI flash to host address
space. However, going forward new platforms might need to support more
decode windows that are not contiguous in the host space. Thus, it is
important to distinguish between offsets from end of region and
addresses in host/SPI flash space and treat them separately.

As a first step towards supporting this requirement for multiple
decode windows on new platforms, this change handles the negative
offset provided as input in dispatch_command before the requested cbfs
operation is performed.

This change adds baseaddress_input, headeroffset_input and
cbfsoffset_input to struct param and converts them to offsets from
start of region before storing into baseaddress, headeroffset and
cbfsoffset if the inputs are negative.

In follow up changes, cbfstool will be extended to add support
for multiple decode windows.

BUG=b:171534504
TEST=Verified using abuild with timeless option for all coreboot
boards that there is no change in the resultant coreboot.rom file.

Change-Id: Ib74a7e6ed9e88fbc5489640d73bedac14872953f
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47829
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2 files changed
tree: 34526a8d4efc8ef7575d9935ae9d83d9667cee01
  1. 3rdparty/
  2. configs/
  3. Documentation/
  4. LICENSES/
  5. payloads/
  6. src/
  7. tests/
  8. util/
  9. .checkpatch.conf
  10. .clang-format
  11. .editorconfig
  12. .gitignore
  13. .gitmodules
  14. .gitreview
  15. AUTHORS
  16. COPYING
  17. gnat.adc
  18. MAINTAINERS
  19. Makefile
  20. Makefile.inc
  21. README.md
  22. 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:

  • 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.