Files
system76-coreboot/payloads/libpayload
Aaron Durbin 8bbd04ea8d libpayload: special case large memalign() requests
For memalign() requests the current allocator keeps metadata
about each chunk of aligned memory that copmrises the size
requested. For large allocations relative to the alignment
this can cause significant metadata overhead. Instead, consider
all memalign() requests whose size meets or exceeds 1KiB or
alignment that meets or exceeds 1KiB large requests.
These requests are handled specially to only allocate
the amount of memory required for the size and alignment
constraints by not allocating any metadata as the whole region
would be consumed by the request.

BUG=None
BRANCH=None
TEST=Built and tested various scenarios. Noted the ability to
     free() and properly coalesce the heap as expected.

Change-Id: Ia9cf5529ca859e490617af296cffd2705c2c6fd8
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 4e32fc57626dac6194c9fd0141df680b4a5417e8
Original-Change-Id: Icdf022831b733e3bb84a2d2f3b499f4e25d89128
Original-Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/242456
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: http://review.coreboot.org/8729
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
2015-03-20 09:59:19 +01:00
..
2015-01-12 05:55:30 +01:00
2012-04-04 00:40:31 +02:00
2015-01-12 05:55:30 +01:00

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