coreboot-kgpe-d16/payloads/libpayload
Julius Werner 09f2921b5d cbfs: Add LZ4 in-place decompression support for pre-RAM stages
This patch ports the LZ4 decompression code that debuted in libpayload
last year to coreboot for use in CBFS stages (upgrading the base
algorithm to LZ4's dev branch to access the new in-place decompression
checks). This is especially useful for pre-RAM stages in constrained
SRAM-based systems, which previously could not be compressed due to
the size requirements of the LZMA scratchpad and bounce buffer. The
LZ4 algorithm offers a very lean decompressor function and in-place
decompression support to achieve roughly the same boot speed gains
(trading compression ratio for decompression time) with nearly no
memory overhead.

For now we only activate it for the stages that had previously not been
compressed at all on non-XIP (read: non-x86) boards. In the future we
may also consider replacing LZMA completely for certain boards, since
which algorithm wins out on boot speed depends on board-specific
parameters (architecture, processor speed, SPI transfer rate, etc.).

BRANCH=None
BUG=None
TEST=Built and booted Oak, Jerry, Nyan and Falco. Measured boot time on
Oak to be about ~20ms faster (cutting load times for affected stages
almost in half).

Change-Id: Iec256c0e6d585d1b69985461939884a54e3ab900
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/13638
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
2016-02-22 21:38:37 +01:00
..
arch libpayload: honor TSC information under CONFIG_LP_TIMER_RDTSC 2016-02-19 19:50:25 +01:00
bin libpayload: Rename PDCurses-3.4 to PDCurses 2015-11-11 21:38:48 +01:00
configs libpayload/configs/config.veyron: Use CONFIG_LP_8250_SERIAL_CONSOLE 2015-12-06 22:24:30 +01:00
crypto libpayload: Make Kconfig bools use IS_ENABLED() 2015-06-30 18:55:15 +02:00
curses libpayload: PDCurses: Remove trailing whitespace 2015-11-20 16:27:36 +01:00
drivers libpayload: use 32bit access when accessing 4byte wide uart registers 2016-02-09 21:53:42 +01:00
gdb tree: drop last paragraph of GPL copyright header 2015-10-31 21:37:39 +01:00
include cbfs: Add LZ4 in-place decompression support for pre-RAM stages 2016-02-22 21:38:37 +01:00
libc libpayload: honor TSC information under CONFIG_LP_TIMER_RDTSC 2016-02-19 19:50:25 +01:00
libcbfs cbfs: Add LZ4 in-place decompression support for pre-RAM stages 2016-02-22 21:38:37 +01:00
liblz4 cbfs: Add LZ4 in-place decompression support for pre-RAM stages 2016-02-22 21:38:37 +01:00
liblzma lzma: Return correct amount of decompressed bytes 2015-07-06 09:40:37 +02:00
libpci Remove empty lines at end of file 2015-06-08 00:55:07 +02:00
sample Remove empty lines at end of file 2015-06-08 00:55:07 +02:00
tests Remove empty lines at end of file 2015-06-08 00:55:07 +02:00
Doxyfile
Kconfig libpayload: Add timer driver for armada38x 2016-02-04 11:32:22 +01:00
LICENSES libpayload: Add LZ4 decompression algorithm 2015-07-09 00:10:16 +02:00
LICENSE_GPL libpayload: Introduce new Kconfig to explicitly allow GPL code 2015-01-09 07:06:27 +01:00
Makefile libpayload: Add missing autoconf dependency 2015-09-10 09:18:12 +00:00
Makefile.inc libpayload: Use CONFIG_LP_CCACHE instead of CONFIG_CCACHE 2015-08-09 21:02:37 +02:00
README Remove empty lines at end of file 2015-06-08 00:55:07 +02:00

README

-------------------------------------------------------------------------------
libpayload README
-------------------------------------------------------------------------------

libpayload is a minimal library to support standalone payloads
that can be booted with firmware like coreboot. It handles the setup
code, and provides common C library symbols such as malloc() and printf().

Note: This is _not_ a standard library for use with an operating system,
rather it's only useful for coreboot payload development!
See http://coreboot.org for details on coreboot.


Installation
------------

 $ git clone http://review.coreboot.org/p/coreboot.git

 $ cd coreboot/payloads/libpayload

 $ make menuconfig

 $ make

 $ sudo make install (optional, will install into /opt per default)

As libpayload is for 32bit x86 systems only, you might have to install the
32bit libgcc version, otherwise your payloads will fail to compile.
On Debian systems you'd do 'apt-get install gcc-multilib' for example.


Usage
-----

Here's an example of a very simple payload (hello.c) and how to build it:

 #include <libpayload.h>

 int main(void)
 {
     printf("Hello, world!\n");
     return 0;
 }

Building the payload using the 'lpgcc' compiler wrapper:

 $ lpgcc -o hello.elf hello.c

Please see the sample/ directory for details.


Website and Mailing List
------------------------

The main website is http://www.coreboot.org/Libpayload.

For additional information, patches, and discussions, please join the
coreboot mailing list at http://coreboot.org/Mailinglist, where most
libpayload developers are subscribed.


Copyright and License
---------------------

See LICENSES.