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Julius Werner fffee873c8 Makefile: Add build-time overlap check for programs loaded after coreboot
On non-x86 platforms, coreboot uses the memlayout.ld mechanism to
statically allocate the different memory regions it needs and guarantees
at build time that there are no dangerous overlaps between them. At the
end of its (ramstage) execution, however, it usually loads a payload
(and possibly other platform-specific components) that is not integrated
into the coreboot build system and therefore cannot provide the same
overlap guarantees through memlayout.ld. This creates a dangerous memory
hazard where a new component could be loaded over memory areas that are
still in use by the code-loading ramstage and lead to arbitrary memory
corruption bugs.

This patch fills this gap in our build-time correctness guarantees by
adding the necessary checks as a new intermediate Makefile target on
route to assembling the final image. It will parse the memory footprint
information of the payload (and other platform-specific post-ramstage
components) from CBFS and compare it to a list of memory areas known to
be still in use during late ramstage, generating a build failure in case
of a possible hazard.

BUG=chrome-os-partner:48008
TEST=Built Oak while moving critical regions in the way of BL31 or the
payload, observing the desired build-time errors. Built Nyan, Jerry and
Falco without issues for good measure.

Change-Id: I3ebd2c1caa4df959421265e26f9cab2c54909b68
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/13949
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
2016-03-09 17:07:14 +01:00
3rdparty vboot: Update to current master to support S3 resume signalling 2016-02-29 20:19:06 +01:00
Documentation Documentation/Intel: Add EDK-II links 2016-03-07 04:17:34 +01:00
payloads payloads: Move secondary payloads inside of a submenu 2016-03-09 17:03:21 +01:00
src Makefile: Add build-time overlap check for programs loaded after coreboot 2016-03-09 17:07:14 +01:00
util Add option for "timeless" builds 2016-03-09 15:25:05 +01:00
.clang-format Provide coreboot coding style formalisation file for clang-format 2015-11-10 00:49:03 +01:00
.gitignore BuildSystem: Add Memtest86+ as a secondary payload 2016-03-05 22:57:53 +01:00
.gitmodules git modules: rename git submodules to avoid hierarchies 2016-02-11 20:55:55 +01:00
.gitreview add .gitreview 2012-11-01 23:13:39 +01:00
COPYING update license template. 2006-08-12 22:03:36 +00:00
MAINTAINERS MAINTAINERS: Add Timothy Pearson to the maintainers list 2016-03-07 20:06:33 +01:00
Makefile Makefile: Update payload clean targets 2016-03-09 17:01:56 +01:00
Makefile.inc Makefile: Add build-time overlap check for programs loaded after coreboot 2016-03-09 17:07:14 +01:00
README README: improve description of compiler requirements 2015-07-30 05:11:33 +02:00
toolchain.inc toolchain.inc: test IASL by version string instead of number 2016-03-04 16:36:25 +01:00

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
------------------

 * 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_TOOLCHAIN Kconfig option if you're feeling lucky (no support in this
   case).
 * iasl (for targets with ACPI support)

Optional:

 * doxygen (for generating/viewing documentation)
 * gdb (for better debugging facilities on some targets)
 * ncurses (for 'make menuconfig' and 'make nconfig')
 * 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.