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review.coreboot.org / coreboot / 41ba01bb95e146fda62e2b778e50965024acf457
commit41ba01bb95e146fda62e2b778e50965024acf457[log] [tgz]
authorRaul E Rangel <rrangel@chromium.org>Fri Jul 23 14:53:05 2021 -0600
committerFelix Held <felix-coreboot@felixheld.de>Wed Oct 20 15:56:28 2021 +0000
tree59107a2b9a167aef160943e597047a45b8c807eb
parent3f41d3269e462c2c0a7d7c4cbdc20f0b07b166ee [diff]
util/cbfstool/rmodule: Omit undefined extern symbols from reloc table

When using `DECLARE_OPTIONAL_REGION`, it is assumed that
REGION_SIZE(name) == 0 if the region was not defined in the memlayout.
When using non-rmodule stages (i.e., bootblock, romstage, etc), this
assumption holds true, but breaks down in rmodule (i.e., ramstage)
stages.

The rmodule tool is not currently omitting undefined externals from the
relocation table. e.g.,

    extern u8 _##name##_size[];

This means that when the rmodule loader runs, it will rewrite the symbol
from 0 (which is the default the linker assumed) to 0 + offset. This is
wrong since the symbol doesn't actually exist. Instead we need to omit
the relocation so it continues to keep the default value of 0.

BUG=b:179699789
TEST=Print out REGION_SIZE(cbfs_cache) in ramstage and verify it is set
to 0.
I also see the following printed by the rmodtool now:

DEBUG: Omitting relocation for undefined extern: _watchdog_tombstone_size
DEBUG: Omitting relocation for undefined extern: _watchdog_tombstone
DEBUG: Omitting relocation for undefined extern: _watchdog_tombstone
DEBUG: Omitting relocation for absolute symbol: _stack_size
DEBUG: Omitting relocation for absolute symbol: _program_size
DEBUG: Omitting relocation for absolute symbol: _cbmem_init_hooks_size
DEBUG: Omitting relocation for absolute symbol: _payload_preload_cache_size
DEBUG: Omitting relocation for absolute symbol: _payload_preload_cache
DEBUG: Omitting relocation for absolute symbol: _payload_preload_cache_size
DEBUG: Omitting relocation for absolute symbol: _payload_preload_cache
DEBUG: Omitting relocation for undefined extern: _cbfs_cache
DEBUG: Omitting relocation for undefined extern: _cbfs_cache_size

As you can see the _watchdog_tombstone will also be fixed by this CL.

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Change-Id: Ib57e263fa9014da4f6854637000c1c8ad8eb351a
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58376
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>
1 file changed
tree: 59107a2b9a167aef160943e597047a45b8c807eb
  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. AUTHORS
  17. COPYING
  18. gnat.adc
  19. MAINTAINERS
  20. Makefile
  21. Makefile.inc
  22. README.md
  23. 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.