Jeremy Compostella 54db255529 libpayload: Support unaligned pointers for memset
The optimization of the memset() function introduced by commit
dbadb1dd634c8c9419215ade0666a7fb69a4447b (libpayload: Reorder default
memcpy, speed up memset and memcmp) is provoking an issue on x86
platform when compiling without the CONFIG_GPL option.

GCC is making use of the movdqa instruction to copy words.  This
instruction can raise a "General Protection Fault Exception" when it
is called on a non-aligned address argument.

Change-Id: I73382a76a4399d8e78244867f2ebb1dca176a6bf
Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
Reviewed-on: https://review.coreboot.org/20524
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
2017-07-12 10:58:55 +00:00
..
2015-06-08 00:55:07 +02:00
2015-06-08 00:55:07 +02:00
2015-06-08 00:55:07 +02:00
2017-06-28 00:56:53 +00:00
2017-01-25 17:58:48 +01:00
2017-06-07 12:05:44 +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 https://www.coreboot.org for details on coreboot.


Installation
------------

 $ git clone https://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 https://www.coreboot.org/Libpayload.

For additional information, patches, and discussions, please join the
coreboot mailing list at https://www.coreboot.org/Mailinglist, where most
libpayload developers are subscribed.


Copyright and License
---------------------

See LICENSES.