include/linux/init.h

   1 #ifndef _LINUX_INIT_H
   2 #define _LINUX_INIT_H
   3
   4 #include <linux/compiler.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  * Also note, that this data cannot be "const".
  39  */
  40
  41 /* These are for everybody (although not all archs will actually
  42    discard it in modules) */
  43 #define __init          __attribute__ ((__section__ (".init.text")))
  44 #define __initdata      __attribute__ ((__section__ (".init.data")))
  45 #define __exitdata      __attribute__ ((__section__(".exit.data")))
  46 #define __exit_call     __attribute_used__ __attribute__ ((__section__ (".exitcall.exit")))
  47
  48 #ifdef MODULE
  49 #define __exit          __attribute__ ((__section__(".exit.text")))
  50 #else
  51 #define __exit          __attribute_used__ __attribute__ ((__section__(".exit.text")))
  52 #endif
  53
  54 /* For assembly routines */
  55 #define __INIT          .section        ".init.text","ax"
  56 #define __FINIT         .previous
  57 #define __INITDATA      .section        ".init.data","aw"
  58
  59 #ifndef __ASSEMBLY__
  60 /*
  61  * Used for initialization calls..
  62  */
  63 typedef int (*initcall_t)(void);
  64 typedef void (*exitcall_t)(void);
  65
  66 extern initcall_t __con_initcall_start[], __con_initcall_end[];
  67 extern initcall_t __security_initcall_start[], __security_initcall_end[];
  68
  69 /* Defined in init/main.c */
  70 extern char saved_command_line[];
  71 extern unsigned int reset_devices;
  72
  73 /* used by init/main.c */
  74 extern void setup_arch(char **);
  75
  76 #endif
  77
  78 #ifndef MODULE
  79
  80 #ifndef __ASSEMBLY__
  81
  82 /* initcalls are now grouped by functionality into separate
  83  * subsections. Ordering inside the subsections is determined
  84  * by link order.
  85  * For backwards compatibility, initcall() puts the call in
  86  * the device init subsection.
  87  */
  88
  89 #define __define_initcall(level,fn) \
  90         static initcall_t __initcall_##fn __attribute_used__ \
  91         __attribute__((__section__(".initcall" level ".init"))) = fn
  92
  93 #define core_initcall(fn)               __define_initcall("1",fn)
  94 #define postcore_initcall(fn)           __define_initcall("2",fn)
  95 #define arch_initcall(fn)               __define_initcall("3",fn)
  96 #define subsys_initcall(fn)             __define_initcall("4",fn)
  97 #define fs_initcall(fn)                 __define_initcall("5",fn)
  98 #define device_initcall(fn)             __define_initcall("6",fn)
  99 #define late_initcall(fn)               __define_initcall("7",fn)
 100
 101 #define __initcall(fn) device_initcall(fn)
 102
 103 #define __exitcall(fn) \
 104         static exitcall_t __exitcall_##fn __exit_call = fn
 105
 106 #define console_initcall(fn) \
 107         static initcall_t __initcall_##fn \
 108         __attribute_used__ __attribute__((__section__(".con_initcall.init")))=fn
 109
 110 #define security_initcall(fn) \
 111         static initcall_t __initcall_##fn \
 112         __attribute_used__ __attribute__((__section__(".security_initcall.init"))) = fn
 113
 114 struct obs_kernel_param {
 115         const char *str;
 116         int (*setup_func)(char *);
 117         int early;
 118 };
 119
 120 /*
 121  * Only for really core code.  See moduleparam.h for the normal way.
 122  *
 123  * Force the alignment so the compiler doesn't space elements of the
 124  * obs_kernel_param "array" too far apart in .init.setup.
 125  */
 126 #define __setup_param(str, unique_id, fn, early)                        \
 127         static char __setup_str_##unique_id[] __initdata = str; \
 128         static struct obs_kernel_param __setup_##unique_id      \
 129                 __attribute_used__                              \
 130                 __attribute__((__section__(".init.setup")))     \
 131                 __attribute__((aligned((sizeof(long)))))        \
 132                 = { __setup_str_##unique_id, fn, early }
 133
 134 #define __setup_null_param(str, unique_id)                      \
 135         __setup_param(str, unique_id, NULL, 0)
 136
 137 #define __setup(str, fn)                                        \
 138         __setup_param(str, fn, fn, 0)
 139
 140 #define __obsolete_setup(str)                                   \
 141         __setup_null_param(str, __LINE__)
 142
 143 /* NOTE: fn is as per module_param, not __setup!  Emits warning if fn
 144  * returns non-zero. */
 145 #define early_param(str, fn)                                    \
 146         __setup_param(str, fn, fn, 1)
 147
 148 /* Relies on saved_command_line being set */
 149 void __init parse_early_param(void);
 150 #endif /* __ASSEMBLY__ */
 151
 152 /**
 153  * module_init() - driver initialization entry point
 154  * @x: function to be run at kernel boot time or module insertion
 155  *
 156  * module_init() will either be called during do_initcalls (if
 157  * builtin) or at module insertion time (if a module).  There can only
 158  * be one per module.
 159  */
 160 #define module_init(x)  __initcall(x);
 161
 162 /**
 163  * module_exit() - driver exit entry point
 164  * @x: function to be run when driver is removed
 165  *
 166  * module_exit() will wrap the driver clean-up code
 167  * with cleanup_module() when used with rmmod when
 168  * the driver is a module.  If the driver is statically
 169  * compiled into the kernel, module_exit() has no effect.
 170  * There can only be one per module.
 171  */
 172 #define module_exit(x)  __exitcall(x);
 173
 174 #else /* MODULE */
 175
 176 /* Don't use these in modules, but some people do... */
 177 #define core_initcall(fn)               module_init(fn)
 178 #define postcore_initcall(fn)           module_init(fn)
 179 #define arch_initcall(fn)               module_init(fn)
 180 #define subsys_initcall(fn)             module_init(fn)
 181 #define fs_initcall(fn)                 module_init(fn)
 182 #define device_initcall(fn)             module_init(fn)
 183 #define late_initcall(fn)               module_init(fn)
 184
 185 #define security_initcall(fn)           module_init(fn)
 186
 187 /* These macros create a dummy inline: gcc 2.9x does not count alias
 188  as usage, hence the `unused function' warning when __init functions
 189  are declared static. We use the dummy __*_module_inline functions
 190  both to kill the warning and check the type of the init/cleanup
 191  function. */
 192
 193 /* Each module must use one module_init(), or one no_module_init */
 194 #define module_init(initfn)                                     \
 195         static inline initcall_t __inittest(void)               \
 196         { return initfn; }                                      \
 197         int init_module(void) __attribute__((alias(#initfn)));
 198
 199 /* This is only required if you want to be unloadable. */
 200 #define module_exit(exitfn)                                     \
 201         static inline exitcall_t __exittest(void)               \
 202         { return exitfn; }                                      \
 203         void cleanup_module(void) __attribute__((alias(#exitfn)));
 204
 205 #define __setup_param(str, unique_id, fn)       /* nothing */
 206 #define __setup_null_param(str, unique_id)      /* nothing */
 207 #define __setup(str, func)                      /* nothing */
 208 #define __obsolete_setup(str)                   /* nothing */
 209 #endif
 210
 211 /* Data marked not to be saved by software_suspend() */
 212 #define __nosavedata __attribute__ ((__section__ (".data.nosave")))
 213
 214 /* This means "can be init if no module support, otherwise module load
 215    may call it." */
 216 #ifdef CONFIG_MODULES
 217 #define __init_or_module
 218 #define __initdata_or_module
 219 #else
 220 #define __init_or_module __init
 221 #define __initdata_or_module __initdata
 222 #endif /*CONFIG_MODULES*/
 223
 224 #ifdef CONFIG_HOTPLUG
 225 #define __devinit
 226 #define __devinitdata
 227 #define __devexit
 228 #define __devexitdata
 229 #else
 230 #define __devinit __init
 231 #define __devinitdata __initdata
 232 #define __devexit __exit
 233 #define __devexitdata __exitdata
 234 #endif
 235
 236 #ifdef CONFIG_HOTPLUG_CPU
 237 #define __cpuinit
 238 #define __cpuinitdata
 239 #define __cpuexit
 240 #define __cpuexitdata
 241 #else
 242 #define __cpuinit       __init
 243 #define __cpuinitdata __initdata
 244 #define __cpuexit __exit
 245 #define __cpuexitdata   __exitdata
 246 #endif
 247
 248 #if defined(CONFIG_MEMORY_HOTPLUG) || defined(CONFIG_ACPI_HOTPLUG_MEMORY) \
 249         || defined(CONFIG_ACPI_HOTPLUG_MEMORY_MODULE)
 250 #define __meminit
 251 #define __meminitdata
 252 #define __memexit
 253 #define __memexitdata
 254 #else
 255 #define __meminit       __init
 256 #define __meminitdata __initdata
 257 #define __memexit __exit
 258 #define __memexitdata   __exitdata
 259 #endif
 260
 261 /* Functions marked as __devexit may be discarded at kernel link time, depending
 262    on config options.  Newer versions of binutils detect references from
 263    retained sections to discarded sections and flag an error.  Pointers to
 264    __devexit functions must use __devexit_p(function_name), the wrapper will
 265    insert either the function_name or NULL, depending on the config options.
 266  */
 267 #if defined(MODULE) || defined(CONFIG_HOTPLUG)
 268 #define __devexit_p(x) x
 269 #else
 270 #define __devexit_p(x) NULL
 271 #endif
 272
 273 #ifdef MODULE
 274 #define __exit_p(x) x
 275 #else
 276 #define __exit_p(x) NULL
 277 #endif
 278
 279 #endif /* _LINUX_INIT_H */