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  * The `id' arg to __define_initcall() is needed so that multiple initcalls
  89  * can point at the same handler without causing duplicate-symbol build errors.
  90  */
  91
  92 #define __define_initcall(level,fn,id) \
  93         static initcall_t __initcall_##fn##id __attribute_used__ \
  94         __attribute__((__section__(".initcall" level ".init"))) = fn
  95
  96 /*
  97  * A "pure" initcall has no dependencies on anything else, and purely
  98  * initializes variables that couldn't be statically initialized.
  99  *
 100  * This only exists for built-in code, not for modules.
 101  */
 102 #define pure_initcall(fn)               __define_initcall("0",fn,1)
 103
 104 #define core_initcall(fn)               __define_initcall("1",fn,1)
 105 #define core_initcall_sync(fn)          __define_initcall("1s",fn,1s)
 106 #define postcore_initcall(fn)           __define_initcall("2",fn,2)
 107 #define postcore_initcall_sync(fn)      __define_initcall("2s",fn,2s)
 108 #define arch_initcall(fn)               __define_initcall("3",fn,3)
 109 #define arch_initcall_sync(fn)          __define_initcall("3s",fn,3s)
 110 #define subsys_initcall(fn)             __define_initcall("4",fn,4)
 111 #define subsys_initcall_sync(fn)        __define_initcall("4s",fn,4s)
 112 #define fs_initcall(fn)                 __define_initcall("5",fn,5)
 113 #define fs_initcall_sync(fn)            __define_initcall("5s",fn,5s)
 114 #define device_initcall(fn)             __define_initcall("6",fn,6)
 115 #define device_initcall_sync(fn)        __define_initcall("6s",fn,6s)
 116 #define late_initcall(fn)               __define_initcall("7",fn,7)
 117 #define late_initcall_sync(fn)          __define_initcall("7s",fn,7s)
 118
 119 #define __initcall(fn) device_initcall(fn)
 120
 121 #define __exitcall(fn) \
 122         static exitcall_t __exitcall_##fn __exit_call = fn
 123
 124 #define console_initcall(fn) \
 125         static initcall_t __initcall_##fn \
 126         __attribute_used__ __attribute__((__section__(".con_initcall.init")))=fn
 127
 128 #define security_initcall(fn) \
 129         static initcall_t __initcall_##fn \
 130         __attribute_used__ __attribute__((__section__(".security_initcall.init"))) = fn
 131
 132 struct obs_kernel_param {
 133         const char *str;
 134         int (*setup_func)(char *);
 135         int early;
 136 };
 137
 138 /*
 139  * Only for really core code.  See moduleparam.h for the normal way.
 140  *
 141  * Force the alignment so the compiler doesn't space elements of the
 142  * obs_kernel_param "array" too far apart in .init.setup.
 143  */
 144 #define __setup_param(str, unique_id, fn, early)                        \
 145         static char __setup_str_##unique_id[] __initdata = str; \
 146         static struct obs_kernel_param __setup_##unique_id      \
 147                 __attribute_used__                              \
 148                 __attribute__((__section__(".init.setup")))     \
 149                 __attribute__((aligned((sizeof(long)))))        \
 150                 = { __setup_str_##unique_id, fn, early }
 151
 152 #define __setup_null_param(str, unique_id)                      \
 153         __setup_param(str, unique_id, NULL, 0)
 154
 155 #define __setup(str, fn)                                        \
 156         __setup_param(str, fn, fn, 0)
 157
 158 #define __obsolete_setup(str)                                   \
 159         __setup_null_param(str, __LINE__)
 160
 161 /* NOTE: fn is as per module_param, not __setup!  Emits warning if fn
 162  * returns non-zero. */
 163 #define early_param(str, fn)                                    \
 164         __setup_param(str, fn, fn, 1)
 165
 166 /* Relies on saved_command_line being set */
 167 void __init parse_early_param(void);
 168 #endif /* __ASSEMBLY__ */
 169
 170 /**
 171  * module_init() - driver initialization entry point
 172  * @x: function to be run at kernel boot time or module insertion
 173  *
 174  * module_init() will either be called during do_initcalls (if
 175  * builtin) or at module insertion time (if a module).  There can only
 176  * be one per module.
 177  */
 178 #define module_init(x)  __initcall(x);
 179
 180 /**
 181  * module_exit() - driver exit entry point
 182  * @x: function to be run when driver is removed
 183  *
 184  * module_exit() will wrap the driver clean-up code
 185  * with cleanup_module() when used with rmmod when
 186  * the driver is a module.  If the driver is statically
 187  * compiled into the kernel, module_exit() has no effect.
 188  * There can only be one per module.
 189  */
 190 #define module_exit(x)  __exitcall(x);
 191
 192 #else /* MODULE */
 193
 194 /* Don't use these in modules, but some people do... */
 195 #define core_initcall(fn)               module_init(fn)
 196 #define postcore_initcall(fn)           module_init(fn)
 197 #define arch_initcall(fn)               module_init(fn)
 198 #define subsys_initcall(fn)             module_init(fn)
 199 #define fs_initcall(fn)                 module_init(fn)
 200 #define device_initcall(fn)             module_init(fn)
 201 #define late_initcall(fn)               module_init(fn)
 202
 203 #define security_initcall(fn)           module_init(fn)
 204
 205 /* These macros create a dummy inline: gcc 2.9x does not count alias
 206  as usage, hence the `unused function' warning when __init functions
 207  are declared static. We use the dummy __*_module_inline functions
 208  both to kill the warning and check the type of the init/cleanup
 209  function. */
 210
 211 /* Each module must use one module_init(), or one no_module_init */
 212 #define module_init(initfn)                                     \
 213         static inline initcall_t __inittest(void)               \
 214         { return initfn; }                                      \
 215         int init_module(void) __attribute__((alias(#initfn)));
 216
 217 /* This is only required if you want to be unloadable. */
 218 #define module_exit(exitfn)                                     \
 219         static inline exitcall_t __exittest(void)               \
 220         { return exitfn; }                                      \
 221         void cleanup_module(void) __attribute__((alias(#exitfn)));
 222
 223 #define __setup_param(str, unique_id, fn)       /* nothing */
 224 #define __setup_null_param(str, unique_id)      /* nothing */
 225 #define __setup(str, func)                      /* nothing */
 226 #define __obsolete_setup(str)                   /* nothing */
 227 #endif
 228
 229 /* Data marked not to be saved by software_suspend() */
 230 #define __nosavedata __attribute__ ((__section__ (".data.nosave")))
 231
 232 /* This means "can be init if no module support, otherwise module load
 233    may call it." */
 234 #ifdef CONFIG_MODULES
 235 #define __init_or_module
 236 #define __initdata_or_module
 237 #else
 238 #define __init_or_module __init
 239 #define __initdata_or_module __initdata
 240 #endif /*CONFIG_MODULES*/
 241
 242 #ifdef CONFIG_HOTPLUG
 243 #define __devinit
 244 #define __devinitdata
 245 #define __devexit
 246 #define __devexitdata
 247 #else
 248 #define __devinit __init
 249 #define __devinitdata __initdata
 250 #define __devexit __exit
 251 #define __devexitdata __exitdata
 252 #endif
 253
 254 #ifdef CONFIG_HOTPLUG_CPU
 255 #define __cpuinit
 256 #define __cpuinitdata
 257 #define __cpuexit
 258 #define __cpuexitdata
 259 #else
 260 #define __cpuinit       __init
 261 #define __cpuinitdata __initdata
 262 #define __cpuexit __exit
 263 #define __cpuexitdata   __exitdata
 264 #endif
 265
 266 #if defined(CONFIG_MEMORY_HOTPLUG) || defined(CONFIG_ACPI_HOTPLUG_MEMORY) \
 267         || defined(CONFIG_ACPI_HOTPLUG_MEMORY_MODULE)
 268 #define __meminit
 269 #define __meminitdata
 270 #define __memexit
 271 #define __memexitdata
 272 #else
 273 #define __meminit       __init
 274 #define __meminitdata __initdata
 275 #define __memexit __exit
 276 #define __memexitdata   __exitdata
 277 #endif
 278
 279 /* Functions marked as __devexit may be discarded at kernel link time, depending
 280    on config options.  Newer versions of binutils detect references from
 281    retained sections to discarded sections and flag an error.  Pointers to
 282    __devexit functions must use __devexit_p(function_name), the wrapper will
 283    insert either the function_name or NULL, depending on the config options.
 284  */
 285 #if defined(MODULE) || defined(CONFIG_HOTPLUG)
 286 #define __devexit_p(x) x
 287 #else
 288 #define __devexit_p(x) NULL
 289 #endif
 290
 291 #ifdef MODULE
 292 #define __exit_p(x) x
 293 #else
 294 #define __exit_p(x) NULL
 295 #endif
 296
 297 #endif /* _LINUX_INIT_H */