d371cf3336
I just got hit by a double-evaluation bug again, it's time to attempt
to fix this once more. Unfortunately there are several issues that don't
make this easy:
- bitfield variables don't support typeof()
- local macro variables that shadow others trigger -Werror=shadow
- sign warnings with integer literal and unsigned var in typeof-MIN()
- ({ statement expressions }) can not be used outside functions
- romcc doesn't support any of the fancy GCC/clang extensions
This patch tries to address all of them as far as possible with macro
magic. We don't have the technology to solve the bitfield and
non-function context issues yet (__builtin_choose_expr() still throws a
"no statement expression outside a function" error if it's only in the
branch that's not chosen, unfortunately), so we'll have to provide
alternative macros for use in those cases (and we'll avoid making
__ALIGN_MASK() double-evaluation safe for now, since it would be
annoying to do that there and having an alignment mask with side
effects seems very unlikely). romcc can continue using unsafe versions
since we're hopefully not writing a lot of new code for it. Sign
warnings can be avoided in literal/variable comparisons by always using
the type of the variable there. Shadowing is avoided by picking very
explicit local variable names and using a special __COUNTER__ solution
for MIN() and MAX() (the only ones of these you're likely to nest).
Also add DIV_ROUND_UP() to libpayload since it's a generally quite
useful thing to have.
Change-Id: Iea35156c9aa9f6f2c7b8f00991418b746f44315d
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32027
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
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:
- https://www.coreboot.org/Supported_Motherboards
- https://www.coreboot.org/Supported_Chipsets_and_Devices
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.