coreboot-kgpe-d16/payloads/libpayload
Gabe Black ec3a462d03 CBFS: Change how the bss is zeroed when loading a stage.
For reasons explained in a previous CL, it might be necessary to "load" a file
from CBFS in place. The loading code in CBFS was, however, zeroing the area of
memory the stage was about to be loaded into. When the CBFS data is located
elsewhere this works fine, but when it isn't you end up clobbering the data
you're trying to load. Also, there's no reason to zero memory we're about to
load something into or have just loaded something into. This change makes it
so that we only zero out the portion of the memory between what was
loaded/decompressed and the final size of the stage in memory.

Change-Id: If34df16bd74b2969583e11ef6a26eb4065842f57
Signed-off-by: Gabe Black <gabeblack@chromium.org>
Reviewed-on: http://review.coreboot.org/3579
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
2013-08-15 20:13:39 +02:00
..
arch ARM: Tell the linker memset and memcpy are functions. 2013-07-10 21:49:45 +02:00
bin libpayload: Make lpgcc wrapper usable for in-tree builds 2013-06-25 16:17:41 +02:00
configs libpayload: Update configs/defconfig file 2012-12-18 15:05:36 +01:00
crypto Change TARGET_I386 to ARCH_X86 2012-11-30 23:20:54 +01:00
curses libpayload: Use longer delay in tinycurses' wgetch() 2013-06-26 20:51:07 +02:00
drivers libpayload: ahci: Increase timeout for signature reading 2013-06-18 19:29:36 +02:00
include CBFS: Change the signature of cbfs_decompress. 2013-08-15 20:10:39 +02:00
libc libpayload: Add strerror 2013-06-28 10:39:57 +02:00
libcbfs CBFS: Change how the bss is zeroed when loading a stage. 2013-08-15 20:13:39 +02:00
liblzma libpayload: Don't do unaligned accesses during LZMA decompression 2013-03-13 23:42:09 +01:00
libpci libpayload: minor cleanups 2012-04-04 00:40:31 +02:00
sample fix compilation of hello.elf example payload. 2010-08-28 23:23:47 +00:00
tests libpayload: initial test case + tiny "framework" 2013-03-22 00:35:32 +01:00
util libpayload: Start using only internal and compiler headers. 2013-03-13 22:04:44 +01:00
Config.in libpayload: Fill gaps in the xHCI driver 2013-06-13 22:21:20 +02:00
Doxyfile Run doxygen -u on doxygen configuration files 2010-06-28 10:40:38 +00:00
LICENSES Since some people disapprove of white space cleanups mixed in regular commits 2010-04-27 06:56:47 +00:00
Makefile libpayload: Fix the config file dependency in the Makefile template 2013-03-18 20:46:09 +01:00
Makefile.inc libpayload: Don't sneak in compiler includes 2013-04-18 02:50:28 +02:00
README libpayload, superiotool: README: Prepend `coreboot/` to path of change directory line 2013-04-04 17:22:15 +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.