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Alexandru Gagniuc 299c265102 Refactor usage of walkcbfs to permit access to CBFS headers
walkcbfs() is used only with ROMCC. Besides finding stages during the
bootblock, it's also used when applying microcode updates during the
bootblock phase. The function used to return only a pointer to the data of
the CBFS file, while making the header completely inaccessible. Since the
header contains the length of the CBFS file, the caller did not have a way
to know how long the data was. Then, other conventions had to be used to
determine the EOF, which might present problems if the user replaces the
CBFS file. This is not an issue when jumping to a stage (romstage), but can
present problems when accessing a microcode file which has not been
NULL-terminated.

Refactor walkcbfs_asm to return a pointer to the CBFS file header rather
than the data. Rename walkcbfs() to walkcbfs_head(), and reimplement a new
walkcbfs() based on walkcbfs_head(). Thus current usage of walkcbfs()
remains unaffected.
The code has been verified to run successfully under qemu.

Subsequent patches will change usage of walkcbfs() to walkcbfs_head where
knowing the length of the data is needed.

Change-Id: I21cbf19e130e1480e2749754e5d5130d36036f8e
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Reviewed-on: http://review.coreboot.org/4504
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
2013-12-09 19:56:57 +01:00
3rdparty@aebd21811d AMD Yangtze: Update 3rdparty hash for new blobs 2013-07-18 20:06:55 +02:00
documentation documentation: Change the file name of document for building Coreboot 2013-12-09 11:13:35 +01:00
payloads Do not export variables to GRUB build 2013-12-06 16:38:51 +01:00
src Refactor usage of walkcbfs to permit access to CBFS headers 2013-12-09 19:56:57 +01:00
util cbfstool: Properly handle EOF in update_fit step 2013-12-09 17:34:25 +01:00
.gitignore gitignore: ignore the crossgcc/build-{arch}-{archive} 2013-12-09 11:13:53 +01:00
.gitmodules gitmodules: Fix 3rdparty updates 2013-06-28 00:56:43 +02:00
.gitreview add .gitreview 2012-11-01 23:13:39 +01:00
COPYING
Makefile arch/x86/Makefile.inc: Pass $(AS) and $(CPP) to SeaBIOS 2013-10-17 01:59:50 +02:00
Makefile.inc Fix build with USE_OPTION_TABLE 2013-12-01 23:15:08 +01:00
README

README

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