d67c6876b5
This patch allows the CBMEM console to persist across reboots, which should greatly help post factum debugging of issues involving multiple reboots. In order to prevent the console from filling up, it will instead operate as a ring buffer that continues to evict the oldest lines once full. (This means that if even a single boot doesn't fit into the buffer, we will now drop the oldest lines whereas previous code would've dropped the newest lines instead.) The console control structure is modified in a sorta backwards-compatible way, so that new readers can continue to work with old console buffers and vice versa. When an old reader reads a new buffer that has already once overflowed (i.e. is operating in true ring buffer mode) it will print lines out of order, but it will at least still print out the whole console content and not do any illegal memory accesses (assuming it correctly implemented cursor overflow as it was already possible before this patch). BUG=chromium:651966 TEST=Rebooted and confirmed output repeatedly on a Kevin and a Falco. Also confirmed correct behavior across suspend/resume for the latter. Change-Id: Ifcbf59d58e1ad20995b98d111c4647281fbb45ff Signed-off-by: Julius Werner <jwerner@chromium.org> Reviewed-on: https://review.coreboot.org/18301 Tested-by: build bot (Jenkins) Reviewed-by: Aaron Durbin <adurbin@chromium.org> |
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|---|---|---|
| .. | ||
| arch | ||
| bin | ||
| configs | ||
| crypto | ||
| curses | ||
| drivers | ||
| gdb | ||
| include | ||
| libc | ||
| libcbfs | ||
| liblz4 | ||
| liblzma | ||
| libpci | ||
| sample | ||
| tests | ||
| Doxyfile | ||
| Kconfig | ||
| LICENSES | ||
| LICENSE_GPL | ||
| Makefile | ||
| Makefile.inc | ||
| README | ||
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.