No description
c09cf0b7e1
To find the coreboot tables, the payload has historically searched for their signature in a predefined region of memory. This is a little clumsy on x86, but it works because you can assume certain regions are RAM. Also, there are areas which are set aside for the firmware by convention. On x86 there's a forwarding entry which goes in one of those fairly small conventional areas and which points to the CBMEM area at the end of memory. On ARM there aren't areas like that, so we've left out the forwarding entry and gone directly to CBMEM. RAM may not start at the beginning of the address space or go to its end, and that means there isn't really anywhere fixed you can put the coreboot tables. That's meant that libpayload has to be configured on a per board basis to know where to look for CBMEM. Now that we have boards that don't have fixed amounts of memory, the location of the end of RAM isn't fixed even on a per board level which means even that workaround will no longer cut it. This change makes coreboot pass the location of the coreboot tables to libpayload using r0, the first argument register. That means we'll be able to find them no matter where CBMEM is, and we can get rid of the per board search ranges. We can extend this mechanism to x86 as well, but there may be more complications and it's less necessary there. It would be a good thing to do eventually though. BUG=None TEST=Built and booted on nyan. Changed the size of memory and saw that the payload could still find the coreboot tables where before it couldn't. Built for pit, snow, and big. BRANCH=None Original-Change-Id: I7218afd999da1662b0db8172fd8125670ceac471 Original-Signed-off-by: Gabe Black <gabeblack@google.com> Original-Reviewed-on: https://chromium-review.googlesource.com/185572 Original-Reviewed-by: Julius Werner <jwerner@chromium.org> Original-Commit-Queue: Gabe Black <gabeblack@chromium.org> Original-Tested-by: Gabe Black <gabeblack@chromium.org> (cherry picked from commit ca88f39c21158b59abe3001f986207a292359cf5) Signed-off-by: Marc Jones <marc.jones@se-eng.com> Change-Id: Iab14e9502b6ce7a55f0a72e190fa582f89f11a1e Reviewed-on: http://review.coreboot.org/7655 Tested-by: build bot (Jenkins) Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net> Reviewed-by: Patrick Georgi <pgeorgi@google.com> |
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| documentation | ||
| payloads | ||
| src | ||
| util | ||
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| COPYING | ||
| Makefile | ||
| Makefile.inc | ||
| README | ||
| toolchain.inc | ||
------------------------------------------------------------------------------- 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 http://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: * http://www.coreboot.org/Supported_Motherboards * http://www.coreboot.org/Supported_Chipsets_and_Devices Build Requirements ------------------ * gcc / g++ * make Optional: * doxygen (for generating/viewing documentation) * iasl (for targets with ACPI support) * gdb (for better debugging facilities on some targets) * ncurses (for 'make menuconfig') * flex and bison (for regenerating parsers) Building coreboot ----------------- Please consult http://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 http://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: http://www.coreboot.org You can contact us directly on the coreboot mailing list: http://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.