ab91407735
clang seems to like to do some aggressive optimizations that break our approach of mocking functions for test by using objcopy to turn them weak after the fact on individual compiled object files. For example, in CB:56601 the function cbfs_get_boot_device() is mocked this way. When compiling the cbfs_boot_lookup() function in src/lib/cbfs.c with clang, it will generate a normal callq instruction to a relocation for cbfs_boot_lookup(), which can then later be pointed to the mocked version of that function. However, it will also somehow infer that the version of cbfs_boot_lookup() in that file can only ever return a pointer to the static local `ro` variable (because CONFIG_VBOOT is disabled in the environment for that particular test), and instead generate instructions that directly load the address of a relocation for that variable into %rdi for the following call to cbfs_lookup(), rather than using the real function return value. (Why it would do that is anyone's guess because this seems unlikely to be faster than just moving the function return value from %rax into %rdi like a normal compiler.) Long story short, this optimization breaks our tests because cbfs_lookup() will be called with the wrong pointer. clang doesn't provide many options to disable individual optimizations, so the only solution seems to be to make clang aware that the function is weak during the compilation stage already, so it can be aware that it may get replaced. This patch implements that by marking the mocked functions weak via #pragma weak lines in the per-test autogenerated config header. Signed-off-by: Julius Werner <jwerner@chromium.org> Change-Id: I1f9011f444248544de7a71bbefc54edc006ae0cd Reviewed-on: https://review.coreboot.org/c/coreboot/+/57009 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Paul Menzel <paulepanter@mailbox.org> Reviewed-by: Jakub Czapiga <jacz@semihalf.com> |
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| Documentation | ||
| LICENSES | ||
| configs | ||
| payloads | ||
| src | ||
| tests | ||
| util | ||
| .checkpatch.conf | ||
| .clang-format | ||
| .editorconfig | ||
| .gitignore | ||
| .gitmodules | ||
| .gitreview | ||
| AUTHORS | ||
| COPYING | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc | ||
| README.md | ||
| gnat.adc | ||
| 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_TOOLCHAINKconfig 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 menuconfigandmake 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:
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.