coreboot-kgpe-d16

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Gabe Black 7756fe70eb x86: Minimize work done with the caches disabled in mtrr functions. The code in src/cpu/x86/mtrr/mtrr.c disables caching in a few places when changing mtrr settings. While I can't find anything that says that's actually required, I can believe it's necessary. With that said, other code around the wrmsr instructions which actually modify the settings should be able to run with caching enabled with no ill effects. This is particularly true for two calls to printk, one in the fixed mtrr code and one in the variable, which could result in an arbitrary amount of work being done without caching. When changing the implementation of the cbmem console, these two printks caused a significant regression in boot performance on link of about 70ms which is about 10% of total firmware boot time. When the window where the cache is disabled is minimized, both this and the new implementation were about 30ms faster than the original boot time. For the variable MTRRs, we now store what we want to set the MSRs to and then write them all at once at the end of commit_var_mtrrs(). This way we don't have some set and some not, but we still minimize the time we spend with the caches disabled. Change-Id: I5139b262bd2d13f79afd88e2e2c0f514fb3e27c9 Signed-off-by: Gabe Black <gabeblack@google.com> Reviewed-on: https://chromium-review.googlesource.com/187811 Reviewed-by: Ronald Minnich <rminnich@chromium.org> Reviewed-by: Aaron Durbin <adurbin@chromium.org> Commit-Queue: Gabe Black <gabeblack@chromium.org> Tested-by: Gabe Black <gabeblack@chromium.org> (cherry picked from commit 31529d6d965676c6cedeb62137eabc26819956fc) Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com> Reviewed-on: http://review.coreboot.org/6952 Tested-by: build bot (Jenkins) Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>		2014-09-24 22:49:45 +02:00
3rdparty@f37e0e64ac	AMD Steppe Eagle: Update reference to BLOBs repo (3rdparty)	2014-09-01 00:37:16 +02:00
documentation	Documentation: Use correct file name for the build guide in the Makefile	2014-07-04 19:03:10 +02:00
payloads	arm: Update mem* functions to newer versions	2014-09-22 18:47:42 +02:00
src	x86: Minimize work done with the caches disabled in mtrr functions.	2014-09-24 22:49:45 +02:00
util	cbfstool: Add AARCH64 reloc types to elf.h	2014-09-23 22:28:20 +02:00
.gitignore	.gitignore: add 3 executables that can be built in util/	2014-08-11 06:26:01 +02:00
.gitmodules	nvidia-cbootimage: add submodule	2014-09-08 18:58:40 +02:00
.gitreview	…
COPYING	…
Makefile	ARM: Generalize armv7 as arm.	2014-09-08 18:59:23 +02:00
Makefile.inc	coreboot arm64: Add support for arm64 into coreboot framework	2014-09-23 18:10:32 +02:00
README	…
toolchain.inc	coreboot arm64: Add support for arm64 into coreboot framework	2014-09-23 18:10:32 +02:00

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

 * 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.