linux-bk/include/linux/init.h History
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   1#ifndef _LINUX_INIT_H
   2#define _LINUX_INIT_H
   3
   4#include <linux/config.h>
   5#include <linux/compiler.h>
   6
   7/* These macros are used to mark some functions or 
   8 * initialized data (doesn't apply to uninitialized data)
   9 * as `initialization' functions. The kernel can take this
  10 * as hint that the function is used only during the initialization
  11 * phase and free up used memory resources after
  12 *
  13 * Usage:
  14 * For functions:
  15 * 
  16 * You should add __init immediately before the function name, like:
  17 *
  18 * static void __init initme(int x, int y)
  19 * {
  20 *    extern int z; z = x * y;
  21 * }
  22 *
  23 * If the function has a prototype somewhere, you can also add
  24 * __init between closing brace of the prototype and semicolon:
  25 *
  26 * extern int initialize_foobar_device(int, int, int) __init;
  27 *
  28 * For initialized data:
  29 * You should insert __initdata between the variable name and equal
  30 * sign followed by value, e.g.:
  31 *
  32 * static int init_variable __initdata = 0;
  33 * static char linux_logo[] __initdata = { 0x32, 0x36, ... };
  34 *
  35 * Don't forget to initialize data not at file scope, i.e. within a function,
  36 * as gcc otherwise puts the data into the bss section and not into the init
  37 * section.
  38 * 
  39 * Also note, that this data cannot be "const".
  40 */
  41
  42/* These are for everybody (although not all archs will actually
  43   discard it in modules) */
  44#define __init          __attribute__ ((__section__ (".init.text")))
  45#define __initdata      __attribute__ ((__section__ (".init.data")))
  46#define __exitdata      __attribute__ ((__section__(".exit.data")))
  47#define __exit_call     __attribute_used__ __attribute__ ((__section__ (".exitcall.exit")))
  48
  49#ifdef MODULE
  50#define __exit          __attribute__ ((__section__(".exit.text")))
  51#else
  52#define __exit          __attribute_used__ __attribute__ ((__section__(".exit.text")))
  53#endif
  54
  55/* For assembly routines */
  56#define __INIT          .section        ".init.text","ax"
  57#define __FINIT         .previous
  58#define __INITDATA      .section        ".init.data","aw"
  59
  60#ifndef __ASSEMBLY__
  61/*
  62 * Used for initialization calls..
  63 */
  64typedef int (*initcall_t)(void);
  65typedef void (*exitcall_t)(void);
  66
  67extern initcall_t __con_initcall_start, __con_initcall_end;
  68extern initcall_t __security_initcall_start, __security_initcall_end;
  69#endif
  70  
  71#ifndef MODULE
  72
  73#ifndef __ASSEMBLY__
  74
  75/* initcalls are now grouped by functionality into separate 
  76 * subsections. Ordering inside the subsections is determined
  77 * by link order. 
  78 * For backwards compatibility, initcall() puts the call in 
  79 * the device init subsection.
  80 */
  81
  82#define __define_initcall(level,fn) \
  83        static initcall_t __initcall_##fn __attribute_used__ \
  84        __attribute__((__section__(".initcall" level ".init"))) = fn
  85
  86#define core_initcall(fn)               __define_initcall("1",fn)
  87#define postcore_initcall(fn)           __define_initcall("2",fn)
  88#define arch_initcall(fn)               __define_initcall("3",fn)
  89#define subsys_initcall(fn)             __define_initcall("4",fn)
  90#define fs_initcall(fn)                 __define_initcall("5",fn)
  91#define device_initcall(fn)             __define_initcall("6",fn)
  92#define late_initcall(fn)               __define_initcall("7",fn)
  93
  94#define __initcall(fn) device_initcall(fn)
  95
  96#define __exitcall(fn) \
  97        static exitcall_t __exitcall_##fn __exit_call = fn
  98
  99#define console_initcall(fn) \
 100        static initcall_t __initcall_##fn \
 101        __attribute_used__ __attribute__((__section__(".con_initcall.init")))=fn
 102
 103#define security_initcall(fn) \
 104        static initcall_t __initcall_##fn \
 105        __attribute_used__ __attribute__((__section__(".security_initcall.init"))) = fn
 106
 107struct obs_kernel_param {
 108        const char *str;
 109        int (*setup_func)(char *);
 110};
 111
 112/* OBSOLETE: see moduleparam.h for the right way. */
 113#define __setup(str, fn)                                        \
 114        static char __setup_str_##fn[] __initdata = str;        \
 115        static struct obs_kernel_param __setup_##fn             \
 116                 __attribute_used__                             \
 117                 __attribute__((__section__(".init.setup")))    \
 118                = { __setup_str_##fn, fn }
 119
 120#endif /* __ASSEMBLY__ */
 121
 122/**
 123 * module_init() - driver initialization entry point
 124 * @x: function to be run at kernel boot time or module insertion
 125 * 
 126 * module_init() will either be called during do_initcalls (if
 127 * builtin) or at module insertion time (if a module).  There can only
 128 * be one per module.
 129 */
 130#define module_init(x)  __initcall(x);
 131
 132/**
 133 * module_exit() - driver exit entry point
 134 * @x: function to be run when driver is removed
 135 * 
 136 * module_exit() will wrap the driver clean-up code
 137 * with cleanup_module() when used with rmmod when
 138 * the driver is a module.  If the driver is statically
 139 * compiled into the kernel, module_exit() has no effect.
 140 * There can only be one per module.
 141 */
 142#define module_exit(x)  __exitcall(x);
 143
 144#else /* MODULE */
 145
 146/* Don't use these in modules, but some people do... */
 147#define core_initcall(fn)               module_init(fn)
 148#define postcore_initcall(fn)           module_init(fn)
 149#define arch_initcall(fn)               module_init(fn)
 150#define subsys_initcall(fn)             module_init(fn)
 151#define fs_initcall(fn)                 module_init(fn)
 152#define device_initcall(fn)             module_init(fn)
 153#define late_initcall(fn)               module_init(fn)
 154
 155#define security_initcall(fn)           module_init(fn)
 156
 157/* These macros create a dummy inline: gcc 2.9x does not count alias
 158 as usage, hence the `unused function' warning when __init functions
 159 are declared static. We use the dummy __*_module_inline functions
 160 both to kill the warning and check the type of the init/cleanup
 161 function. */
 162
 163/* Each module must use one module_init(), or one no_module_init */
 164#define module_init(initfn)                                     \
 165        static inline initcall_t __inittest(void)               \
 166        { return initfn; }                                      \
 167        int init_module(void) __attribute__((alias(#initfn)));
 168
 169/* This is only required if you want to be unloadable. */
 170#define module_exit(exitfn)                                     \
 171        static inline exitcall_t __exittest(void)               \
 172        { return exitfn; }                                      \
 173        void cleanup_module(void) __attribute__((alias(#exitfn)));
 174
 175#define __setup(str,func) /* nothing */
 176#endif
 177
 178/* Data marked not to be saved by software_suspend() */
 179#define __nosavedata __attribute__ ((__section__ (".data.nosave")))
 180
 181/* This means "can be init if no module support, otherwise module load
 182   may call it." */
 183#ifdef CONFIG_MODULES
 184#define __init_or_module
 185#define __initdata_or_module
 186#else
 187#define __init_or_module __init
 188#define __initdata_or_module __initdata
 189#endif /*CONFIG_MODULES*/
 190
 191#ifdef CONFIG_HOTPLUG
 192#define __devinit
 193#define __devinitdata
 194#define __devexit
 195#define __devexitdata
 196#else
 197#define __devinit __init
 198#define __devinitdata __initdata
 199#define __devexit __exit
 200#define __devexitdata __exitdata
 201#endif
 202
 203/* Functions marked as __devexit may be discarded at kernel link time, depending
 204   on config options.  Newer versions of binutils detect references from
 205   retained sections to discarded sections and flag an error.  Pointers to
 206   __devexit functions must use __devexit_p(function_name), the wrapper will
 207   insert either the function_name or NULL, depending on the config options.
 208 */
 209#if defined(MODULE) || defined(CONFIG_HOTPLUG)
 210#define __devexit_p(x) x
 211#else
 212#define __devexit_p(x) NULL
 213#endif
 214
 215#ifdef MODULE
 216#define __exit_p(x) x
 217#else
 218#define __exit_p(x) NULL
 219#endif
 220
 221#endif /* _LINUX_INIT_H */
 222
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