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Julius Werner e9879c0fbd CBFS: Automate ROM image layout and remove hardcoded offsets
Non-x86 boards currently need to hardcode the position of their CBFS
master header in a Kconfig. This is very brittle because it is usually
put in between the bootblock and the first CBFS entry, without any
checks to guarantee that it won't overlap either of those. It is not fun
to debug random failures that move and disappear with tiny alignment
changes because someone decided to write "ORBC1112" over some part of
your data section (in a way that is not visible in the symbolized .elf
binaries, only in the final image). This patch seeks to prevent those
issues and reduce the need for manual configuration by making the image
layout a completely automated part of cbfstool.

Since automated placement of the CBFS header means we can no longer
hardcode its position into coreboot, this patch takes the existing x86
solution of placing a pointer to the header at the very end of the
CBFS-managed section of the ROM and generalizes it to all architectures.
This is now even possible with the read-only/read-write split in
ChromeOS, since coreboot knows how large that section is from the
CBFS_SIZE Kconfig (which is by default equal to ROM_SIZE, but can be
changed on systems that place other data next to coreboot/CBFS in ROM).

Also adds a feature to cbfstool that makes the -B (bootblock file name)
argument on image creation optional, since we have recently found valid
use cases for CBFS images that are not the first boot medium of the
device (instead opened by an earlier bootloader that can already
interpret CBFS) and therefore don't really need a bootblock.

BRANCH=None
BUG=None
TEST=Built and booted on Veyron_Pinky, Nyan_Blaze and Falco.

Change-Id: Ifcc755326832755cfbccd6f0a12104cba28a20af
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/229975
2014-12-03 06:09:54 +00:00
configs configs: Align ChromeOS board configs to CBFS_SIZE change 2014-12-03 06:09:49 +00:00
documentation documentation: Add documentation for timestamp library 2014-11-14 23:57:04 +00:00
payloads CBFS: Automate ROM image layout and remove hardcoded offsets 2014-12-03 06:09:54 +00:00
src CBFS: Automate ROM image layout and remove hardcoded offsets 2014-12-03 06:09:54 +00:00
util CBFS: Automate ROM image layout and remove hardcoded offsets 2014-12-03 06:09:54 +00:00
.gitignore rmodules: add support for rmodtool 2014-03-31 22:25:57 +00:00
COMMIT-QUEUE.ini COMMIT-QUEUE.ini: Add documentation. 2013-11-01 14:08:42 +00:00
COPYING update license template. 2006-08-12 22:03:36 +00:00
Makefile Makefile: Change $(generic-deps) to order-only prerequisite 2014-10-04 03:10:51 +00:00
Makefile.inc CBFS: Correct ROM_SIZE for ARM boards, use CBFS_SIZE for cbfstool 2014-12-03 06:09:40 +00:00
PRESUBMIT.cfg chromeos: Add PRESUBMIT.cfg 2013-05-01 14:31:10 -07:00
README Update README with newer version of the text from the web page 2011-06-15 10:16:33 +02:00
toolchain.inc arch/mips: Add base MIPS architecture support 2014-09-01 11:05:57 +00:00

-------------------------------------------------------------------------------
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.