init.h 9.4 KB

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  1. #ifndef _LINUX_INIT_H
  2. #define _LINUX_INIT_H
  3. #include <linux/compiler.h>
  4. /* These macros are used to mark some functions or
  5. * initialized data (doesn't apply to uninitialized data)
  6. * as `initialization' functions. The kernel can take this
  7. * as hint that the function is used only during the initialization
  8. * phase and free up used memory resources after
  9. *
  10. * Usage:
  11. * For functions:
  12. *
  13. * You should add __init immediately before the function name, like:
  14. *
  15. * static void __init initme(int x, int y)
  16. * {
  17. * extern int z; z = x * y;
  18. * }
  19. *
  20. * If the function has a prototype somewhere, you can also add
  21. * __init between closing brace of the prototype and semicolon:
  22. *
  23. * extern int initialize_foobar_device(int, int, int) __init;
  24. *
  25. * For initialized data:
  26. * You should insert __initdata between the variable name and equal
  27. * sign followed by value, e.g.:
  28. *
  29. * static int init_variable __initdata = 0;
  30. * static char linux_logo[] __initdata = { 0x32, 0x36, ... };
  31. *
  32. * Don't forget to initialize data not at file scope, i.e. within a function,
  33. * as gcc otherwise puts the data into the bss section and not into the init
  34. * section.
  35. *
  36. * Also note, that this data cannot be "const".
  37. */
  38. /* These are for everybody (although not all archs will actually
  39. discard it in modules) */
  40. #define __init __attribute__ ((__section__ (".init.text")))
  41. #define __initdata __attribute__ ((__section__ (".init.data")))
  42. #define __exitdata __attribute__ ((__section__(".exit.data")))
  43. #define __exit_call __attribute_used__ __attribute__ ((__section__ (".exitcall.exit")))
  44. #ifdef MODULE
  45. #define __exit __attribute__ ((__section__(".exit.text")))
  46. #else
  47. #define __exit __attribute_used__ __attribute__ ((__section__(".exit.text")))
  48. #endif
  49. /* For assembly routines */
  50. #define __INIT .section ".init.text","ax"
  51. #define __FINIT .previous
  52. #define __INITDATA .section ".init.data","aw"
  53. #ifndef __ASSEMBLY__
  54. /*
  55. * Used for initialization calls..
  56. */
  57. typedef int (*initcall_t)(void);
  58. typedef void (*exitcall_t)(void);
  59. extern initcall_t __con_initcall_start[], __con_initcall_end[];
  60. extern initcall_t __security_initcall_start[], __security_initcall_end[];
  61. /* Defined in init/main.c */
  62. extern char __initdata boot_command_line[];
  63. extern char *saved_command_line;
  64. extern unsigned int reset_devices;
  65. /* used by init/main.c */
  66. extern void setup_arch(char **);
  67. #endif
  68. #ifndef MODULE
  69. #ifndef __ASSEMBLY__
  70. /* initcalls are now grouped by functionality into separate
  71. * subsections. Ordering inside the subsections is determined
  72. * by link order.
  73. * For backwards compatibility, initcall() puts the call in
  74. * the device init subsection.
  75. *
  76. * The `id' arg to __define_initcall() is needed so that multiple initcalls
  77. * can point at the same handler without causing duplicate-symbol build errors.
  78. */
  79. #define __define_initcall(level,fn,id) \
  80. static initcall_t __initcall_##fn##id __attribute_used__ \
  81. __attribute__((__section__(".initcall" level ".init"))) = fn
  82. /*
  83. * A "pure" initcall has no dependencies on anything else, and purely
  84. * initializes variables that couldn't be statically initialized.
  85. *
  86. * This only exists for built-in code, not for modules.
  87. */
  88. #define pure_initcall(fn) __define_initcall("0",fn,1)
  89. #define core_initcall(fn) __define_initcall("1",fn,1)
  90. #define core_initcall_sync(fn) __define_initcall("1s",fn,1s)
  91. #define postcore_initcall(fn) __define_initcall("2",fn,2)
  92. #define postcore_initcall_sync(fn) __define_initcall("2s",fn,2s)
  93. #define arch_initcall(fn) __define_initcall("3",fn,3)
  94. #define arch_initcall_sync(fn) __define_initcall("3s",fn,3s)
  95. #define subsys_initcall(fn) __define_initcall("4",fn,4)
  96. #define subsys_initcall_sync(fn) __define_initcall("4s",fn,4s)
  97. #define fs_initcall(fn) __define_initcall("5",fn,5)
  98. #define fs_initcall_sync(fn) __define_initcall("5s",fn,5s)
  99. #define rootfs_initcall(fn) __define_initcall("rootfs",fn,rootfs)
  100. #define device_initcall(fn) __define_initcall("6",fn,6)
  101. #define device_initcall_sync(fn) __define_initcall("6s",fn,6s)
  102. #define late_initcall(fn) __define_initcall("7",fn,7)
  103. #define late_initcall_sync(fn) __define_initcall("7s",fn,7s)
  104. #define __initcall(fn) device_initcall(fn)
  105. #define __exitcall(fn) \
  106. static exitcall_t __exitcall_##fn __exit_call = fn
  107. #define console_initcall(fn) \
  108. static initcall_t __initcall_##fn \
  109. __attribute_used__ __attribute__((__section__(".con_initcall.init")))=fn
  110. #define security_initcall(fn) \
  111. static initcall_t __initcall_##fn \
  112. __attribute_used__ __attribute__((__section__(".security_initcall.init"))) = fn
  113. struct obs_kernel_param {
  114. const char *str;
  115. int (*setup_func)(char *);
  116. int early;
  117. };
  118. /*
  119. * Only for really core code. See moduleparam.h for the normal way.
  120. *
  121. * Force the alignment so the compiler doesn't space elements of the
  122. * obs_kernel_param "array" too far apart in .init.setup.
  123. */
  124. #define __setup_param(str, unique_id, fn, early) \
  125. static char __setup_str_##unique_id[] __initdata = str; \
  126. static struct obs_kernel_param __setup_##unique_id \
  127. __attribute_used__ \
  128. __attribute__((__section__(".init.setup"))) \
  129. __attribute__((aligned((sizeof(long))))) \
  130. = { __setup_str_##unique_id, fn, early }
  131. #define __setup_null_param(str, unique_id) \
  132. __setup_param(str, unique_id, NULL, 0)
  133. #define __setup(str, fn) \
  134. __setup_param(str, fn, fn, 0)
  135. #define __obsolete_setup(str) \
  136. __setup_null_param(str, __LINE__)
  137. /* NOTE: fn is as per module_param, not __setup! Emits warning if fn
  138. * returns non-zero. */
  139. #define early_param(str, fn) \
  140. __setup_param(str, fn, fn, 1)
  141. /* Relies on boot_command_line being set */
  142. void __init parse_early_param(void);
  143. #endif /* __ASSEMBLY__ */
  144. /**
  145. * module_init() - driver initialization entry point
  146. * @x: function to be run at kernel boot time or module insertion
  147. *
  148. * module_init() will either be called during do_initcalls() (if
  149. * builtin) or at module insertion time (if a module). There can only
  150. * be one per module.
  151. */
  152. #define module_init(x) __initcall(x);
  153. /**
  154. * module_exit() - driver exit entry point
  155. * @x: function to be run when driver is removed
  156. *
  157. * module_exit() will wrap the driver clean-up code
  158. * with cleanup_module() when used with rmmod when
  159. * the driver is a module. If the driver is statically
  160. * compiled into the kernel, module_exit() has no effect.
  161. * There can only be one per module.
  162. */
  163. #define module_exit(x) __exitcall(x);
  164. #else /* MODULE */
  165. /* Don't use these in modules, but some people do... */
  166. #define core_initcall(fn) module_init(fn)
  167. #define postcore_initcall(fn) module_init(fn)
  168. #define arch_initcall(fn) module_init(fn)
  169. #define subsys_initcall(fn) module_init(fn)
  170. #define fs_initcall(fn) module_init(fn)
  171. #define device_initcall(fn) module_init(fn)
  172. #define late_initcall(fn) module_init(fn)
  173. #define security_initcall(fn) module_init(fn)
  174. /* These macros create a dummy inline: gcc 2.9x does not count alias
  175. as usage, hence the `unused function' warning when __init functions
  176. are declared static. We use the dummy __*_module_inline functions
  177. both to kill the warning and check the type of the init/cleanup
  178. function. */
  179. /* Each module must use one module_init(), or one no_module_init */
  180. #define module_init(initfn) \
  181. static inline initcall_t __inittest(void) \
  182. { return initfn; } \
  183. int init_module(void) __attribute__((alias(#initfn)));
  184. /* This is only required if you want to be unloadable. */
  185. #define module_exit(exitfn) \
  186. static inline exitcall_t __exittest(void) \
  187. { return exitfn; } \
  188. void cleanup_module(void) __attribute__((alias(#exitfn)));
  189. #define __setup_param(str, unique_id, fn) /* nothing */
  190. #define __setup_null_param(str, unique_id) /* nothing */
  191. #define __setup(str, func) /* nothing */
  192. #define __obsolete_setup(str) /* nothing */
  193. #endif
  194. /* Data marked not to be saved by software_suspend() */
  195. #define __nosavedata __attribute__ ((__section__ (".data.nosave")))
  196. /* This means "can be init if no module support, otherwise module load
  197. may call it." */
  198. #ifdef CONFIG_MODULES
  199. #define __init_or_module
  200. #define __initdata_or_module
  201. #else
  202. #define __init_or_module __init
  203. #define __initdata_or_module __initdata
  204. #endif /*CONFIG_MODULES*/
  205. #ifdef CONFIG_HOTPLUG
  206. #define __devinit
  207. #define __devinitdata
  208. #define __devexit
  209. #define __devexitdata
  210. #else
  211. #define __devinit __init
  212. #define __devinitdata __initdata
  213. #define __devexit __exit
  214. #define __devexitdata __exitdata
  215. #endif
  216. #ifdef CONFIG_HOTPLUG_CPU
  217. #define __cpuinit
  218. #define __cpuinitdata
  219. #define __cpuexit
  220. #define __cpuexitdata
  221. #else
  222. #define __cpuinit __init
  223. #define __cpuinitdata __initdata
  224. #define __cpuexit __exit
  225. #define __cpuexitdata __exitdata
  226. #endif
  227. #if defined(CONFIG_MEMORY_HOTPLUG) || defined(CONFIG_ACPI_HOTPLUG_MEMORY) \
  228. || defined(CONFIG_ACPI_HOTPLUG_MEMORY_MODULE)
  229. #define __meminit
  230. #define __meminitdata
  231. #define __memexit
  232. #define __memexitdata
  233. #else
  234. #define __meminit __init
  235. #define __meminitdata __initdata
  236. #define __memexit __exit
  237. #define __memexitdata __exitdata
  238. #endif
  239. /* Functions marked as __devexit may be discarded at kernel link time, depending
  240. on config options. Newer versions of binutils detect references from
  241. retained sections to discarded sections and flag an error. Pointers to
  242. __devexit functions must use __devexit_p(function_name), the wrapper will
  243. insert either the function_name or NULL, depending on the config options.
  244. */
  245. #if defined(MODULE) || defined(CONFIG_HOTPLUG)
  246. #define __devexit_p(x) x
  247. #else
  248. #define __devexit_p(x) NULL
  249. #endif
  250. #ifdef MODULE
  251. #define __exit_p(x) x
  252. #else
  253. #define __exit_p(x) NULL
  254. #endif
  255. #endif /* _LINUX_INIT_H */