HC Yen 11e743ce26 libpayload arm64: Add helper functions with el argument
Allow read/write to registers at a given el. Also, make read/write
registers at current el call this newly added function.

BRANCH=none
BUG=none
TEST=build and boot on mt8173-evb

Change-Id: Id69f0fdc07193c5c7e997712f0cd99de6f41510b
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: c091917babc39d9ab997f51f81b486c9aa900c24
Original-Change-Id: I0944946642066b88331e497a92388e74e86902d0
Original-Signed-off-by: HC Yen <hc.yen@mediatek.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/240322
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/8798
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
2015-03-21 13:43:03 +01:00
..
2012-04-04 00:40:31 +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.