Libpayload
The wiki is being retired!
Documentation is now handled by the same processes we use for code: Add something to the Documentation/ directory in the coreboot repo, and it will be rendered to https://doc.coreboot.org/. Contributions welcome!
Overview
Currently a concept rather than shipping code, libpayload is a coreboot subproject that intends to provide a lightweight implementation of common and useful functions for coreboot payloads. The benefits of linking a coreboot payload against libpayload are:
- payloads do not have to implement and maintain low-level code for I/O, common functions, etc,
- payloads can be recompiled and deployed for CPU architectures supported by coreboot in the future,
- libpayload functions tested and scrutinized outside payload development,
- payloads themselves may be partly host-tested, e.g. against an emulation libpayload,
- leads to the possibility of payloads using dynamic linking, reducing total payload footprint.
just give us a main() and a pocket full of dreams and we'll do the rest
Feature Wish List
- Basics
- coreboot services and structures (e.g. read CMOS, device tree)
- subset of C-library functions (e.g. printf, puts, getch)
- light ncurses from the Google Summer Of Code project
- Fancies
- directFB
- TWIN
Libc Coverage
| Function/Macro/Variable | Status |
|---|---|
| assert.h | |
assert( ) (macro)
|
no |
| ctype.h | |
int isalnum(int character)
|
no |
int isalpha(int character)
|
no |
int iscntrl(int character)
|
no |
int isdigit(int character)
|
no |
int isgraph(int character)
|
no |
int islower(int character)
|
no |
int isprint(int character)
|
no |
int ispunct(int character)
|
no |
int isspace(int character)
|
no |
int isupper(int character)
|
no |
int isxdigit(int character)
|
no |
| errno.h | |
errno (global)
|
no |
| float.h | |
| limits.h | |
| locale.h | |
char *setlocale(int category, const char *locale)
|
no |
struct lconv *localeconv(void)
|
no |
| math.h | |
| TODO | |
| setjmp.h | |
| TODO | |
| signal.h | |
| TODO | |
| stdarg.h | |
| TODO | |
| stddef.h | |
| TODO | |
| stdio.h | |
| TODO | |
| stdlib.h | |
| TODO | |
| string.h | |
| TODO | |
| time.h | |
| TODO | |
| No Support |
| Partial Support |
| Full Support |
Usage Example
hello_payload.c:
#include <stdio.h>
int main( void )
{
printf( "Hello, world!\n" );
return 0;
}
build:
libpayload-gcc -o hello_payload hello_payload.c