LXR linux-old/include/linux/init.h

   1#ifndef _LINUX_INIT_H
   2#define _LINUX_INIT_H
   3
   4#include <linux/config.h>
   5
   6/* These macros are used to mark some functions or 
   7 * initialized data (doesn't apply to uninitialized data)
   8 * as `initialization' functions. The kernel can take this
   9 * as hint that the function is used only during the initialization
  10 * phase and free up used memory resources after
  11 *
  12 * Usage:
  13 * For functions:
  14 * 
  15 * You should add __init immediately before the function name, like:
  16 *
  17 * static void __init initme(int x, int y)
  18 * {
  19 *    extern int z; z = x * y;
  20 * }
  21 *
  22 * If the function has a prototype somewhere, you can also add
  23 * __init between closing brace of the prototype and semicolon:
  24 *
  25 * extern int initialize_foobar_device(int, int, int) __init;
  26 *
  27 * For initialized data:
  28 * You should insert __initdata between the variable name and equal
  29 * sign followed by value, e.g.:
  30 *
  31 * static int init_variable __initdata = 0;
  32 * static char linux_logo[] __initdata = { 0x32, 0x36, ... };
  33 *
  34 * Don't forget to initialize data not at file scope, i.e. within a function,
  35 * as gcc otherwise puts the data into the bss section and not into the init
  36 * section.
  37 */
  38
  39#ifndef MODULE
  40
  41#ifndef __ASSEMBLY__
  42
  43/*
  44 * Used for initialization calls..
  45 */
  46typedef int (*initcall_t)(void);
  47typedef void (*exitcall_t)(void);
  48
  49extern initcall_t __initcall_start, __initcall_end;
  50
  51#define __initcall(fn)                                                          \
  52        static initcall_t __initcall_##fn __init_call = fn
  53#define __exitcall(fn)                                                          \
  54        static exitcall_t __exitcall_##fn __exit_call = fn
  55
  56/*
  57 * Used for kernel command line parameter setup
  58 */
  59struct kernel_param {
  60        const char *str;
  61        int (*setup_func)(char *);
  62};
  63
  64extern struct kernel_param __setup_start, __setup_end;
  65
  66#define __setup(str, fn)                                                                \
  67        static char __setup_str_##fn[] __initdata = str;                                \
  68        static struct kernel_param __setup_##fn __attribute__((unused)) __initsetup = { __setup_str_##fn, fn }
  69
  70#endif /* __ASSEMBLY__ */
  71
  72/*
  73 * Mark functions and data as being only used at initialization
  74 * or exit time.
  75 */
  76#define __init          __attribute__ ((__section__ (".text.init")))
  77#define __exit          __attribute__ ((unused, __section__(".text.exit")))
  78#define __initdata      __attribute__ ((__section__ (".data.init")))
  79#define __exitdata      __attribute__ ((unused, __section__ (".data.exit")))
  80#define __initsetup     __attribute__ ((unused,__section__ (".setup.init")))
  81#define __init_call     __attribute__ ((unused,__section__ (".initcall.init")))
  82#define __exit_call     __attribute__ ((unused,__section__ (".exitcall.exit")))
  83
  84/* For assembly routines */
  85#define __INIT          .section        ".text.init","ax"
  86#define __FINIT         .previous
  87#define __INITDATA      .section        ".data.init","aw"
  88
  89#define module_init(x)  __initcall(x);
  90#define module_exit(x)  __exitcall(x);
  91
  92#else
  93
  94#define __init
  95#define __exit
  96#define __initdata
  97#define __exitdata
  98#define __initcall(fn)
  99/* For assembly routines */
 100#define __INIT
 101#define __FINIT
 102#define __INITDATA
 103
 104/* These macros create a dummy inline: gcc 2.9x does not count alias
 105 as usage, hence the `unused function' warning when __init functions
 106 are declared static. We use the dummy __*_module_inline functions
 107 both to kill the warning and check the type of the init/cleanup
 108 function. */
 109typedef int (*__init_module_func_t)(void);
 110typedef void (*__cleanup_module_func_t)(void);
 111#define module_init(x) \
 112        int init_module(void) __attribute__((alias(#x))); \
 113        extern inline __init_module_func_t __init_module_inline(void) \
 114        { return x; }
 115#define module_exit(x) \
 116        void cleanup_module(void) __attribute__((alias(#x))); \
 117        extern inline __cleanup_module_func_t __cleanup_module_inline(void) \
 118        { return x; }
 119
 120#define __setup(str,func) /* nothing */
 121
 122#endif
 123
 124#ifdef CONFIG_HOTPLUG
 125#define __devinit
 126#define __devinitdata
 127#define __devexit
 128#define __devexitdata
 129#else
 130#define __devinit __init
 131#define __devinitdata __initdata
 132#define __devexit __exit
 133#define __devexitdata __exitdata
 134#endif
 135
 136#endif /* _LINUX_INIT_H */
 137