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 __initdata boot_command_line[];
  71 extern char *saved_command_line;
  72 extern unsigned int reset_devices;
  73
  74 /* used by init/main.c */
  75 extern void setup_arch(char **);
  76
  77 #endif
  78
  79 #ifndef MODULE
  80
  81 #ifndef __ASSEMBLY__
  82
  83 /* initcalls are now grouped by functionality into separate
  84  * subsections. Ordering inside the subsections is determined
  85  * by link order.
  86  * For backwards compatibility, initcall() puts the call in
  87  * the device init subsection.
  88  *
  89  * The `id' arg to __define_initcall() is needed so that multiple initcalls
  90  * can point at the same handler without causing duplicate-symbol build errors.
  91  */
  92
  93 #define __define_initcall(level,fn,id) \
  94         static initcall_t __initcall_##fn##id __attribute_used__ \
  95         __attribute__((__section__(".initcall" level ".init"))) = fn
  96
  97 /*
  98  * A "pure" initcall has no dependencies on anything else, and purely
  99  * initializes variables that couldn't be statically initialized.
 100  *
 101  * This only exists for built-in code, not for modules.
 102  */
 103 #define pure_initcall(fn)               __define_initcall("0",fn,1)
 104
 105 #define core_initcall(fn)               __define_initcall("1",fn,1)
 106 #define core_initcall_sync(fn)          __define_initcall("1s",fn,1s)
 107 #define postcore_initcall(fn)           __define_initcall("2",fn,2)
 108 #define postcore_initcall_sync(fn)      __define_initcall("2s",fn,2s)
 109 #define arch_initcall(fn)               __define_initcall("3",fn,3)
 110 #define arch_initcall_sync(fn)          __define_initcall("3s",fn,3s)
 111 #define subsys_initcall(fn)             __define_initcall("4",fn,4)
 112 #define subsys_initcall_sync(fn)        __define_initcall("4s",fn,4s)
 113 #define fs_initcall(fn)                 __define_initcall("5",fn,5)
 114 #define fs_initcall_sync(fn)            __define_initcall("5s",fn,5s)
 115 #define rootfs_initcall(fn)             __define_initcall("rootfs",fn,rootfs)
 116 #define device_initcall(fn)             __define_initcall("6",fn,6)
 117 #define device_initcall_sync(fn)        __define_initcall("6s",fn,6s)
 118 #define late_initcall(fn)               __define_initcall("7",fn,7)
 119 #define late_initcall_sync(fn)          __define_initcall("7s",fn,7s)
 120
 121 #define __initcall(fn) device_initcall(fn)
 122
 123 #define __exitcall(fn) \
 124         static exitcall_t __exitcall_##fn __exit_call = fn
 125
 126 #define console_initcall(fn) \
 127         static initcall_t __initcall_##fn \
 128         __attribute_used__ __attribute__((__section__(".con_initcall.init")))=fn
 129
 130 #define security_initcall(fn) \
 131         static initcall_t __initcall_##fn \
 132         __attribute_used__ __attribute__((__section__(".security_initcall.init"))) = fn
 133
 134 struct obs_kernel_param {
 135         const char *str;
 136         int (*setup_func)(char *);
 137         int early;
 138 };
 139
 140 /*
 141  * Only for really core code.  See moduleparam.h for the normal way.
 142  *
 143  * Force the alignment so the compiler doesn't space elements of the
 144  * obs_kernel_param "array" too far apart in .init.setup.
 145  */
 146 #define __setup_param(str, unique_id, fn, early)                        \
 147         static char __setup_str_##unique_id[] __initdata = str; \
 148         static struct obs_kernel_param __setup_##unique_id      \
 149                 __attribute_used__                              \
 150                 __attribute__((__section__(".init.setup")))     \
 151                 __attribute__((aligned((sizeof(long)))))        \
 152                 = { __setup_str_##unique_id, fn, early }
 153
 154 #define __setup_null_param(str, unique_id)                      \
 155         __setup_param(str, unique_id, NULL, 0)
 156
 157 #define __setup(str, fn)                                        \
 158         __setup_param(str, fn, fn, 0)
 159
 160 #define __obsolete_setup(str)                                   \
 161         __setup_null_param(str, __LINE__)
 162
 163 /* NOTE: fn is as per module_param, not __setup!  Emits warning if fn
 164  * returns non-zero. */
 165 #define early_param(str, fn)                                    \
 166         __setup_param(str, fn, fn, 1)
 167
 168 /* Relies on boot_command_line being set */
 169 void __init parse_early_param(void);
 170 #endif /* __ASSEMBLY__ */
 171
 172 /**
 173  * module_init() - driver initialization entry point
 174  * @x: function to be run at kernel boot time or module insertion
 175  *
 176  * module_init() will either be called during do_initcalls() (if
 177  * builtin) or at module insertion time (if a module).  There can only
 178  * be one per module.
 179  */
 180 #define module_init(x)  __initcall(x);
 181
 182 /**
 183  * module_exit() - driver exit entry point
 184  * @x: function to be run when driver is removed
 185  *
 186  * module_exit() will wrap the driver clean-up code
 187  * with cleanup_module() when used with rmmod when
 188  * the driver is a module.  If the driver is statically
 189  * compiled into the kernel, module_exit() has no effect.
 190  * There can only be one per module.
 191  */
 192 #define module_exit(x)  __exitcall(x);
 193
 194 #else /* MODULE */
 195
 196 /* Don't use these in modules, but some people do... */
 197 #define core_initcall(fn)               module_init(fn)
 198 #define postcore_initcall(fn)           module_init(fn)
 199 #define arch_initcall(fn)               module_init(fn)
 200 #define subsys_initcall(fn)             module_init(fn)
 201 #define fs_initcall(fn)                 module_init(fn)
 202 #define device_initcall(fn)             module_init(fn)
 203 #define late_initcall(fn)               module_init(fn)
 204
 205 #define security_initcall(fn)           module_init(fn)
 206
 207 /* These macros create a dummy inline: gcc 2.9x does not count alias
 208  as usage, hence the `unused function' warning when __init functions
 209  are declared static. We use the dummy __*_module_inline functions
 210  both to kill the warning and check the type of the init/cleanup
 211  function. */
 212
 213 /* Each module must use one module_init(), or one no_module_init */
 214 #define module_init(initfn)                                     \
 215         static inline initcall_t __inittest(void)               \
 216         { return initfn; }                                      \
 217         int init_module(void) __attribute__((alias(#initfn)));
 218
 219 /* This is only required if you want to be unloadable. */
 220 #define module_exit(exitfn)                                     \
 221         static inline exitcall_t __exittest(void)               \
 222         { return exitfn; }                                      \
 223         void cleanup_module(void) __attribute__((alias(#exitfn)));
 224
 225 #define __setup_param(str, unique_id, fn)       /* nothing */
 226 #define __setup_null_param(str, unique_id)      /* nothing */
 227 #define __setup(str, func)                      /* nothing */
 228 #define __obsolete_setup(str)                   /* nothing */
 229 #endif
 230
 231 /* Data marked not to be saved by software_suspend() */
 232 #define __nosavedata __attribute__ ((__section__ (".data.nosave")))
 233
 234 /* This means "can be init if no module support, otherwise module load
 235    may call it." */
 236 #ifdef CONFIG_MODULES
 237 #define __init_or_module
 238 #define __initdata_or_module
 239 #else
 240 #define __init_or_module __init
 241 #define __initdata_or_module __initdata
 242 #endif /*CONFIG_MODULES*/
 243
 244 #ifdef CONFIG_HOTPLUG
 245 #define __devinit
 246 #define __devinitdata
 247 #define __devexit
 248 #define __devexitdata
 249 #else
 250 #define __devinit __init
 251 #define __devinitdata __initdata
 252 #define __devexit __exit
 253 #define __devexitdata __exitdata
 254 #endif
 255
 256 #ifdef CONFIG_HOTPLUG_CPU
 257 #define __cpuinit
 258 #define __cpuinitdata
 259 #define __cpuexit
 260 #define __cpuexitdata
 261 #else
 262 #define __cpuinit       __init
 263 #define __cpuinitdata __initdata
 264 #define __cpuexit __exit
 265 #define __cpuexitdata   __exitdata
 266 #endif
 267
 268 #if defined(CONFIG_MEMORY_HOTPLUG) || defined(CONFIG_ACPI_HOTPLUG_MEMORY) \
 269         || defined(CONFIG_ACPI_HOTPLUG_MEMORY_MODULE)
 270 #define __meminit
 271 #define __meminitdata
 272 #define __memexit
 273 #define __memexitdata
 274 #else
 275 #define __meminit       __init
 276 #define __meminitdata __initdata
 277 #define __memexit __exit
 278 #define __memexitdata   __exitdata
 279 #endif
 280
 281 /* Functions marked as __devexit may be discarded at kernel link time, depending
 282    on config options.  Newer versions of binutils detect references from
 283    retained sections to discarded sections and flag an error.  Pointers to
 284    __devexit functions must use __devexit_p(function_name), the wrapper will
 285    insert either the function_name or NULL, depending on the config options.
 286  */
 287 #if defined(MODULE) || defined(CONFIG_HOTPLUG)
 288 #define __devexit_p(x) x
 289 #else
 290 #define __devexit_p(x) NULL
 291 #endif
 292
 293 #ifdef MODULE
 294 #define __exit_p(x) x
 295 #else
 296 #define __exit_p(x) NULL
 297 #endif
 298
 299 #endif /* _LINUX_INIT_H */