coreboot-kgpe-d16/payloads/libpayload
Julius Werner d67c6876b5 Turn CBMEM console into a ring buffer that can persist across reboots
This patch allows the CBMEM console to persist across reboots, which
should greatly help post factum debugging of issues involving multiple
reboots. In order to prevent the console from filling up, it will
instead operate as a ring buffer that continues to evict the oldest
lines once full. (This means that if even a single boot doesn't fit into
the buffer, we will now drop the oldest lines whereas previous code
would've dropped the newest lines instead.)

The console control structure is modified in a sorta
backwards-compatible way, so that new readers can continue to work with
old console buffers and vice versa. When an old reader reads a new
buffer that has already once overflowed (i.e. is operating in true ring
buffer mode) it will print lines out of order, but it will at least
still print out the whole console content and not do any illegal memory
accesses (assuming it correctly implemented cursor overflow as it was
already possible before this patch).

BUG=chromium:651966
TEST=Rebooted and confirmed output repeatedly on a Kevin and a Falco.
Also confirmed correct behavior across suspend/resume for the latter.

Change-Id: Ifcbf59d58e1ad20995b98d111c4647281fbb45ff
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/18301
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
2017-04-20 00:29:07 +02:00
..
arch libpayload-x86: Enable SSE and FPU when present 2017-03-08 04:44:12 +01:00
bin libpayload: Move base address, stack and heap size to Kconfig 2016-03-15 20:53:38 +01:00
configs libpayload: Add gru config 2017-04-07 21:33:19 +02:00
crypto libpayload: Make Kconfig bools use IS_ENABLED() 2015-06-30 18:55:15 +02:00
curses libpayload/.../PDCurses: Improve compatibility with ncurses 2016-12-14 18:02:51 +01:00
drivers Turn CBMEM console into a ring buffer that can persist across reboots 2017-04-20 00:29:07 +02:00
gdb tree: drop last paragraph of GPL copyright header 2015-10-31 21:37:39 +01:00
include libpayload: multiboot - support meminfo flag 2017-02-17 18:20:38 +01:00
libc libpayload/libc/console: Flush input driver buffer on init 2017-04-19 19:19:56 +02:00
libcbfs libpayload: cbfs: Fix minor memory leak in some edge cases 2016-08-12 22:52:22 +02:00
liblz4 cbfs: Add LZ4 in-place decompression support for pre-RAM stages 2016-02-22 21:38:37 +01:00
liblzma libpayload: lzma: Allocate scratchpad on the heap 2016-08-08 19:02:07 +02:00
libpci
sample
tests
Doxyfile
Kconfig libpayload: Reintroduce CONFIG_LP_CHROMEOS to set suitable defaults 2016-10-17 22:46:11 +02:00
LICENSES libpayload: Add LZ4 decompression algorithm 2015-07-09 00:10:16 +02:00
LICENSE_GPL
Makefile libpayload: fix build 2017-01-25 17:58:48 +01:00
Makefile.inc libpayload: update junit.xml target, clean up output 2016-03-25 18:18:27 +01:00
README

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.