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Aaron Durbin 0f35af8f42 arch/x86: add support for cache-as-ram paging
Processors, such as glk, need to have paging enabled while
in cache-as-ram mode because the front end is agressive about
fetching lines into the L1I cache. If the line is dirty and in
the L1D then it writes it back to "memory". However, in this case
there is no backing store so the cache-as-ram data that was written
back transforms to all 0xff's when read back in causing corruption.

In order to mitigate the failure add x86 architecture support for
enabling paging while in cache-as-ram mode. A Kconfig variable,
NUM_CAR_PAGE_TABLE_PAGES, determines the number of pages to carve
out for page tables within the cache-as-ram region. Additionally,
the page directory pointer table is also carved out of cache-as-ram.
Both areas are allocated from the persist-across-stages region
of cache-as-ram so all stages utilizing cache-as-ram don't corrupt
the page tables.

The two paging-related areas are loaded by calling
paging_enable_for_car() with the names of cbfs files to load the
initial paging structures from.

BUG=b:72728953

Change-Id: I7ea6e3e7be94a0ef9fd3205ce848e539bfbdcb6e
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/25717
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Justin TerAvest <teravest@chromium.org>
2018-04-25 15:32:56 +00:00
3rdparty 3rdparty/libgfxinit: Update submodule pointer 2018-04-13 16:42:48 +00:00
Documentation Documentation/timestamp.md: Fix markdown formatting 2018-04-17 17:18:23 +00:00
configs configs: Add intel/harcuvar FSP 2.0 sample configuration 2017-10-04 02:56:33 +00:00
payloads libpayload: Move GDB functions to stdlib.h 2018-04-19 20:39:29 +00:00
src arch/x86: add support for cache-as-ram paging 2018-04-25 15:32:56 +00:00
util util/riscvtools: Rename to util/riscv/ 2018-04-25 11:43:20 +00:00
.checkpatch.conf .checkpatch.conf: Ignore CORRUPTED_PATCH lint 2017-10-29 10:11:58 +00:00
.clang-format clang-format: Update .clang-format to be compliant with linux kernel coding style 2018-04-23 09:26:08 +00:00
.gitignore util/blobtool: rename to bincfg 2018-01-18 13:47:20 +00:00
.gitmodules Set up 3rdparty/libgfxinit 2016-10-29 01:35:03 +02:00
.gitreview
COPYING
MAINTAINERS MAINTAINERS: change second PC Engines maintainer 2018-03-21 18:25:49 +00:00
Makefile Makefile: Add filelist to help 2018-01-29 15:35:11 +00:00
Makefile.inc device: Include devicetree in SMM stage 2018-02-22 09:55:19 +00:00
README README: Update requirements 2017-06-27 17:04:32 +00:00
gnat.adc gnat.adc: Do not generate assertion code for Refined_Post 2016-10-29 01:33:31 +02:00
toolchain.inc toolchain: Always use GCC for Ada sources 2017-09-23 10:57:40 +00:00

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 https://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:

 * https://www.coreboot.org/Supported_Motherboards
 * https://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)
 * pkg-config
 * libssl-dev (openssl)

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 https://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 https://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:

  https://www.coreboot.org

You can contact us directly on the coreboot mailing list:

  https://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.