kern/include/linker_func.h

/* Copyright (c) 2014 The Regents of the University of California
 * Barret Rhoden <brho@cs.berkeley.edu>
 * See LICENSE for details.
 *
 * Linker functions.  These are functions of type void func(void) that are
 * automatically run during the kernel initialization.
 *
 * There are different levels; the functions of lower levels are run before
 * higher levels.  There is no guarantee of ordering of functions within a
 * level.
 *
 * To use, simply add the __init tag and the appropriate init_func_X(func);
 *
 * 		static void foo(void)
 * 		{
 * 			bar();
 * 		}
 *
 * becomes
 *
 * 		static void __init foo(void)
 * 		{
 * 			bar();
 * 		}
 * 		init_func_3(foo);
 *
 * And foo() will run during the third level of functions.
 *
 * For now, all levels are run sequentially, and with interrupts enabled. */

#pragma once

#define __init

#define __linkerfunc1  __attribute__((__section__(".linkerfunc1")))
#define __linkerfunc2  __attribute__((__section__(".linkerfunc2")))
#define __linkerfunc3  __attribute__((__section__(".linkerfunc3")))
#define __linkerfunc4  __attribute__((__section__(".linkerfunc4")))

typedef void (*linker_func_t)(void);

/* Casting for the sake of Linux functions, which return an int. */
#define init_func_1(x) linker_func_t __linkerfunc1 __##x = (linker_func_t)(x);
#define init_func_2(x) linker_func_t __linkerfunc2 __##x = (linker_func_t)(x);
#define init_func_3(x) linker_func_t __linkerfunc3 __##x = (linker_func_t)(x);
#define init_func_4(x) linker_func_t __linkerfunc4 __##x = (linker_func_t)(x);

extern linker_func_t __linkerfunc1start[];
extern linker_func_t __linkerfunc1end[];
extern linker_func_t __linkerfunc2start[];
extern linker_func_t __linkerfunc2end[];
extern linker_func_t __linkerfunc3start[];
extern linker_func_t __linkerfunc3end[];
extern linker_func_t __linkerfunc4start[];
extern linker_func_t __linkerfunc4end[];