coreboot-kgpe-d16/payloads/libpayload
Julius Werner 989e12bb63 arm: Fix stored PC value when handling exceptions
ARM processors save the PC value in the Link Register when they handle
and exception, but they store it with an added offset (depending on the
exception type). In order to make crashes easier to read and correctly
support more complicated handlers in libpayload, this patch adjusts the
saved PC value on exception entry to correct for that offset.

(Note: The value that we now store is what ARM calls the "preferred
return address". For most exceptions this is the faulting instruction,
but for software interrupts (SWI) it is the instruction after that. This
is the way most programs like GDB expect the stored PC address to work,
so let's leave it at that.)

Numbers taken from the Architecture Reference Manual at the end of
section B1.8.3.

BRANCH=none
BUG=chrome-os-partner:18390
TEST=Provoked a data abort and an undefined instruction in both coreboot
and depthcharge, confirmed that the PC address was spot on.

Original-Change-Id: Ia958a7edfcd4aa5e04c20148140a6148586935ba
Original-Signed-off-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/199844
Original-Reviewed-by: Stefan Reinauer <reinauer@chromium.org>
Original-Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
(cherry picked from commit 4a914d36bb181d090f75b1414158846d40dc9bac)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: Ib63ca973d5f037a879b4d4d258a4983160b67dd6
Reviewed-on: http://review.coreboot.org/7992
Tested-by: build bot (Jenkins)
Reviewed-by: David Hendricks <dhendrix@chromium.org>
2015-01-03 00:26:18 +01:00
..
arch arm: Fix stored PC value when handling exceptions 2015-01-03 00:26:18 +01:00
bin libpaylod: fix lpgcc logic statement 2014-12-30 19:12:11 +01:00
configs libpayload: Remove PC Keyboard from ARM build 2014-12-30 19:08:37 +01:00
crypto libpayload: Change CONFIG_* to CONFIG_LP_* in the kconfig. 2014-08-05 18:44:08 +02:00
curses libpayload: Change CONFIG_* to CONFIG_LP_* in the kconfig. 2014-08-05 18:44:08 +02:00
drivers libpayload: Fix pointer related casts 2014-12-31 18:57:35 +01:00
include libpayload: Fix pointer related casts 2014-12-31 18:57:35 +01:00
libc libpayload: Fix pointer related casts 2014-12-31 18:57:35 +01:00
libcbfs libpayload: Fix pointer related casts 2014-12-31 18:57:35 +01:00
liblzma LZMA: Add a version of ulzma which takes the input and output buffer sizes. 2014-08-10 22:29:51 +02:00
libpci libpayload: minor cleanups 2012-04-04 00:40:31 +02:00
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 libpayload: also support armv7-a toolchain 2014-10-16 15:54:16 +02:00
Config.in libpayload: Remove PC Keyboard from ARM build 2014-12-30 19:08:37 +01:00
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: Don't use default path for kconfig 2014-10-17 11:25:10 +02:00
Makefile.inc libpayload: Do not tolerate compilation warnings when building 2014-12-31 19:06:16 +01:00
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.