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Julius Werner 8d8799a33a arm, arm64, mips: Add rough static stack size checks with -Wstack-usage
We've seen an increasing need to reduce stack sizes more and more for
space reasons, and it's always guesswork because no one has a good idea
how little is too litte. We now have boards with 3K and 2K stacks, and
old pieces of common code often allocate large temporary buffers that
would lead to very dangerous and hard to detect bugs when someone
eventually tries to use them on one of those.

This patch tries improve this situation at least a bit by declaring 2K
as the minimum stack size all of coreboot code should work with. It
checks all function frames with -Wstack-usage=1536 to make sure we don't
allocate more than 1.5K in a single buffer. This is of course not a
perfect test, but it should catch the most common situation of declaring
a single, large buffer in some close-to-leaf function (with the
assumption that 0.5K is hopefully enough for all the "normal" functions
above that).

Change one example where we were a bit overzealous and put a 1K buffer
into BSS back to stack allocation, since it actually conforms to this
new assumption and frees up another kilobyte of that highly sought-after
verstage space. Not touching x86 with any of this since it's lack of
__PRE_RAM__ BSS often requires it to allocate way more on the stack than
would usually be considered sane.

BRANCH=veyron
BUG=None
TEST=Compiled Cosmos, Daisy, Falco, Blaze, Pit, Storm, Urara and Pinky,
made sure they still build as well as before and don't show any stack
usage warnings.

Change-Id: Idc53d33bd8487bbef49d3ecd751914b0308006ec
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 8e5931066575e256dfc2295c3dab7f0e1b65417f
Original-Change-Id: I30bd9c2c77e0e0623df89b9e5bb43ed29506be98
Original-Signed-off-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/236978
Original-Reviewed-by: David Hendricks <dhendrix@chromium.org>
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/9729
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
2015-07-29 20:25:59 +02:00
3rdparty vboot: Don't count boot attempts if lid is closed 2015-07-08 19:40:24 +02:00
Documentation Remove empty lines at end of file 2015-06-08 00:55:07 +02:00
payloads libpayload: lz4: Add output overrun check to incompressible case 2015-07-21 21:27:42 +02:00
src arm, arm64, mips: Add rough static stack size checks with -Wstack-usage 2015-07-29 20:25:59 +02:00
util crossgcc: Support /bin/sh pointing to dash 2015-07-22 01:44:54 +02:00
.gitignore version: allow stating the coreboot revision in .coreboot-version 2015-07-13 21:00:59 +02:00
.gitmodules submodules: add arm-trusted-firmware third-party repository 2015-06-23 08:20:24 +02:00
.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: grab build system responsibility 2015-05-22 22:47:03 +02:00
Makefile Makefile: Fix KCONFIG_AUTOHEADER dependencies 2015-07-18 09:41:31 +02:00
Makefile.inc cbfstool: fix alignment to 64 byte 2015-07-15 16:34:30 +02:00
README Update README with newer version of the text from the web page 2011-06-15 10:16:33 +02:00
toolchain.inc arm, arm64, mips: Add rough static stack size checks with -Wstack-usage 2015-07-29 20:25:59 +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.