coreboot/payloads/libpayload
Gabe Black e838749425 ARM: Tell the linker memset and memcpy are functions.
The memset and memcpy functions are assembled as ARM code, likely because
that's the default of the assembler. Without special annotation, the assembler
and linker don't know that those symbols are functions which need special
handling so that ARM/thumb issues are handled properly. This change adds that
annotation which gets those functions working in Coreboot which is compiled as
thumb. Libpayload and depthcharge are compiled as ARM so they don't *need* the
annotation since it just works out in ARM mode, but it's the safe thing to do
in case we change that in the future.

We should explicitly select ARM vs. thumb when assembling assembly files to be
consistent across builds and toolchains.

BUG=None
TEST=Built with the assembly versions of memcpy and memset turned on and saw
that we could boot after this change where we couldn't before. Disassembled a
function which calls memset and saw that it was using the blx instruction
which can change mode instead of the bl instruction which can't.
BRANCH=None

Change-Id: Ic3ef4faf17d3467b5042c944106b8743d517cce3
Signed-off-by: Gabe Black <gabeblack@google.com>
Reviewed-on: https://gerrit.chromium.org/gerrit/58728
Commit-Queue: Gabe Black <gabeblack@chromium.org>
Reviewed-by: Gabe Black <gabeblack@chromium.org>
Tested-by: Gabe Black <gabeblack@chromium.org>
Reviewed-by: David Hendricks <dhendrix@chromium.org>
Reviewed-by: Stefan Reinauer <reinauer@google.com>
2013-06-14 18:16:58 -07:00
..
arch ARM: Tell the linker memset and memcpy are functions. 2013-06-14 18:16:58 -07:00
bin libpayload: Drop PowerPC architecture 2013-06-13 15:50:38 -07:00
configs peppy: Initial mainboard commit 2013-05-28 12:53:54 -07:00
crypto libpayload: fix wrong endian assumption in sha1.c 2013-06-13 17:21:22 -07:00
curses PDCurses: pdcscrn.c: Use #ifdef instead of #if CONFIG_SPEAKER 2013-04-01 23:24:38 +02:00
drivers libpayload: usb mass storage card hot plug 2013-06-09 15:03:16 -07:00
include libpayload: Drop PowerPC architecture 2013-06-13 15:50:38 -07:00
libc libpayload: fix size_t handling 2013-03-26 19:35:28 +01:00
libcbfs libpayload: expose cbfs ram functions 2013-05-24 16:27:51 -07:00
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: Fix xcompile 2013-05-21 20:14:26 -07:00
Config.in libpayload: Drop PowerPC architecture 2013-06-13 15:50:38 -07:00
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: Drop PowerPC architecture 2013-06-13 15:50:38 -07:00
Makefile.inc libpayload: Drop PowerPC architecture 2013-06-13 15:50:38 -07:00
README libpayload, superiotool: README: Prepend coreboot/ to path of change directory line 2013-04-04 17:22:15 +02:00

-------------------------------------------------------------------------------
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.