coreboot-kgpe-d16/payloads/libpayload
Julius Werner 623368113c arm64: Decouple MMU functions from memranges
The current arm64 MMU interface is difficult to use in pre-RAM
environments. It is based on the memranges API which makes use of
malloc(), and early stages usually don't have a heap. It is also built
as a one-shot interface that requires all memory ranges to be laid out
beforehand, which is a problem when existing areas need to change (e.g.
after initializing DRAM).

The long-term goal of this patch is to completely switch to a
configure-as-you-go interface based on the mmu_config_range() function,
similar to what ARM32 does. As a first step this feature is added
side-by-side to the existing interface so that existing SoC
implementations continue to work and can be slowly ported over one by
one. Like the ARM32 version it does not garbage collect page tables that
become unused, so repeated mapping at different granularities will
exhaust the available table space (this is presumed to be a reasonable
limitation for a firmware environment and keeps the code much simpler).

Also do some cleanup, align comments between coreboot and libpayload for
easier diffing, and change all error cases to assert()s. Right now the
code just propagates error codes up the stack until it eventually
reaches a function that doesn't check them anymore. MMU configuration
errors (essentially just misaligned requests and running out of table
space) should always be compile-time programming errors, so failing hard
and fast seems like the best way to deal with them.

BRANCH=None
BUG=None
TEST=Compile-tested rush_ryu. Booted on Oak and hacked MMU init to use
mmu_config_range() insted of memranges. Confirmed that CRCs over all page
tables before and after the change are equal.

Change-Id: I93585b44a277c1d96d31ee9c3dd2522b5e10085b
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: f10fcba107aba1f3ea239471cb5a4f9239809539
Original-Change-Id: I6a2a11e3b94e6ae9e1553871f0cccd3b556b3e65
Original-Signed-off-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/271991
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/10304
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
2015-06-02 11:34:23 +02:00
..
arch arm64: Decouple MMU functions from memranges 2015-06-02 11:34:23 +02:00
bin libpayload: arch/mips: Add basic MIPS architecture support 2015-03-21 11:07:50 +01:00
configs cygnus: enable serial driver for depthcharge 2015-04-21 08:25:54 +02:00
crypto libpayload: Change CONFIG_* to CONFIG_LP_* in the kconfig. 2014-08-05 18:44:08 +02:00
curses libpayload/PDcurses: avoid NULL deref 2015-01-03 23:58:22 +01:00
drivers Remove address from GPLv2 headers 2015-05-21 20:50:25 +02:00
gdb Remove address from GPLv2 headers 2015-05-21 20:50:25 +02:00
include arm64: Decouple MMU functions from memranges 2015-06-02 11:34:23 +02:00
libc libpayload: cros: add serial number from coreboot table 2015-04-22 08:46:37 +02:00
libcbfs CBFS: Automate ROM image layout and remove hardcoded offsets 2015-04-14 09:01:27 +02:00
liblzma LZMA: Add a version of ulzma which takes the input and output buffer sizes. 2014-08-10 22:29:51 +02:00
libpci
sample libpayload: Fix missed CONFIG_ -> CONFIG_LP_ substitutions 2014-10-17 11:24:15 +02:00
tests libpayload: Change CONFIG_X86_SERIAL_CONSOLE to CONFIG_8250_SERIAL_CONSOLE 2014-08-28 01:40:48 +02:00
util Remove address from GPLv2 headers 2015-05-21 20:50:25 +02:00
Config.in libpayload: add mediatek timer driver 2015-05-18 13:20:00 +02:00
Doxyfile
LICENSES libpayload: Introduce new Kconfig to explicitly allow GPL code 2015-01-09 07:06:27 +01:00
LICENSE_GPL libpayload: Introduce new Kconfig to explicitly allow GPL code 2015-01-09 07:06:27 +01:00
Makefile libpayload: arch/mips: Add basic MIPS architecture support 2015-03-21 11:07:50 +01:00
Makefile.inc libpayload: avoid hanging on make junit.xml 2015-04-14 16:39:42 +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.