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 #ifdef CONFIG_HOTPLUG_CPU
  56 #define __INIT          .section        ".text","ax"
  57 #define __INITDATA      .section        ".data","aw"
  58 #else
  59 #define __INIT          .section        ".init.text","ax"
  60 #define __INITDATA      .section        ".init.data","aw"
  61 #endif
  62 #define __FINIT         .previous
  63
  64 #ifndef __ASSEMBLY__
  65 /*
  66  * Used for initialization calls..
  67  */
  68 typedef int (*initcall_t)(void);
  69 typedef void (*exitcall_t)(void);
  70
  71 extern initcall_t __con_initcall_start[], __con_initcall_end[];
  72 extern initcall_t __security_initcall_start[], __security_initcall_end[];
  73
  74 /* Defined in init/main.c */
  75 extern char __initdata boot_command_line[];
  76 extern char *saved_command_line;
  77 extern unsigned int reset_devices;
  78
  79 /* used by init/main.c */
  80 extern void setup_arch(char **);
  81
  82 #endif
  83
  84 #ifndef MODULE
  85
  86 #ifndef __ASSEMBLY__
  87
  88 /* initcalls are now grouped by functionality into separate
  89  * subsections. Ordering inside the subsections is determined
  90  * by link order.
  91  * For backwards compatibility, initcall() puts the call in
  92  * the device init subsection.
  93  *
  94  * The `id' arg to __define_initcall() is needed so that multiple initcalls
  95  * can point at the same handler without causing duplicate-symbol build errors.
  96  */
  97
  98 #define __define_initcall(level,fn,id) \
  99         static initcall_t __initcall_##fn##id __attribute_used__ \
 100         __attribute__((__section__(".initcall" level ".init"))) = fn
 101
 102 /*
 103  * A "pure" initcall has no dependencies on anything else, and purely
 104  * initializes variables that couldn't be statically initialized.
 105  *
 106  * This only exists for built-in code, not for modules.
 107  */
 108 #define pure_initcall(fn)               __define_initcall("0",fn,1)
 109
 110 #define core_initcall(fn)               __define_initcall("1",fn,1)
 111 #define core_initcall_sync(fn)          __define_initcall("1s",fn,1s)
 112 #define postcore_initcall(fn)           __define_initcall("2",fn,2)
 113 #define postcore_initcall_sync(fn)      __define_initcall("2s",fn,2s)
 114 #define arch_initcall(fn)               __define_initcall("3",fn,3)
 115 #define arch_initcall_sync(fn)          __define_initcall("3s",fn,3s)
 116 #define subsys_initcall(fn)             __define_initcall("4",fn,4)
 117 #define subsys_initcall_sync(fn)        __define_initcall("4s",fn,4s)
 118 #define fs_initcall(fn)                 __define_initcall("5",fn,5)
 119 #define fs_initcall_sync(fn)            __define_initcall("5s",fn,5s)
 120 #define rootfs_initcall(fn)             __define_initcall("rootfs",fn,rootfs)
 121 #define device_initcall(fn)             __define_initcall("6",fn,6)
 122 #define device_initcall_sync(fn)        __define_initcall("6s",fn,6s)
 123 #define late_initcall(fn)               __define_initcall("7",fn,7)
 124 #define late_initcall_sync(fn)          __define_initcall("7s",fn,7s)
 125
 126 #define __initcall(fn) device_initcall(fn)
 127
 128 #define __exitcall(fn) \
 129         static exitcall_t __exitcall_##fn __exit_call = fn
 130
 131 #define console_initcall(fn) \
 132         static initcall_t __initcall_##fn \
 133         __attribute_used__ __attribute__((__section__(".con_initcall.init")))=fn
 134
 135 #define security_initcall(fn) \
 136         static initcall_t __initcall_##fn \
 137         __attribute_used__ __attribute__((__section__(".security_initcall.init"))) = fn
 138
 139 struct obs_kernel_param {
 140         const char *str;
 141         int (*setup_func)(char *);
 142         int early;
 143 };
 144
 145 /*
 146  * Only for really core code.  See moduleparam.h for the normal way.
 147  *
 148  * Force the alignment so the compiler doesn't space elements of the
 149  * obs_kernel_param "array" too far apart in .init.setup.
 150  */
 151 #define __setup_param(str, unique_id, fn, early)                        \
 152         static char __setup_str_##unique_id[] __initdata = str; \
 153         static struct obs_kernel_param __setup_##unique_id      \
 154                 __attribute_used__                              \
 155                 __attribute__((__section__(".init.setup")))     \
 156                 __attribute__((aligned((sizeof(long)))))        \
 157                 = { __setup_str_##unique_id, fn, early }
 158
 159 #define __setup_null_param(str, unique_id)                      \
 160         __setup_param(str, unique_id, NULL, 0)
 161
 162 #define __setup(str, fn)                                        \
 163         __setup_param(str, fn, fn, 0)
 164
 165 #define __obsolete_setup(str)                                   \
 166         __setup_null_param(str, __LINE__)
 167
 168 /* NOTE: fn is as per module_param, not __setup!  Emits warning if fn
 169  * returns non-zero. */
 170 #define early_param(str, fn)                                    \
 171         __setup_param(str, fn, fn, 1)
 172
 173 /* Relies on boot_command_line being set */
 174 void __init parse_early_param(void);
 175 #endif /* __ASSEMBLY__ */
 176
 177 /**
 178  * module_init() - driver initialization entry point
 179  * @x: function to be run at kernel boot time or module insertion
 180  *
 181  * module_init() will either be called during do_initcalls() (if
 182  * builtin) or at module insertion time (if a module).  There can only
 183  * be one per module.
 184  */
 185 #define module_init(x)  __initcall(x);
 186
 187 /**
 188  * module_exit() - driver exit entry point
 189  * @x: function to be run when driver is removed
 190  *
 191  * module_exit() will wrap the driver clean-up code
 192  * with cleanup_module() when used with rmmod when
 193  * the driver is a module.  If the driver is statically
 194  * compiled into the kernel, module_exit() has no effect.
 195  * There can only be one per module.
 196  */
 197 #define module_exit(x)  __exitcall(x);
 198
 199 #else /* MODULE */
 200
 201 /* Don't use these in modules, but some people do... */
 202 #define core_initcall(fn)               module_init(fn)
 203 #define postcore_initcall(fn)           module_init(fn)
 204 #define arch_initcall(fn)               module_init(fn)
 205 #define subsys_initcall(fn)             module_init(fn)
 206 #define fs_initcall(fn)                 module_init(fn)
 207 #define device_initcall(fn)             module_init(fn)
 208 #define late_initcall(fn)               module_init(fn)
 209
 210 #define security_initcall(fn)           module_init(fn)
 211
 212 /* These macros create a dummy inline: gcc 2.9x does not count alias
 213  as usage, hence the `unused function' warning when __init functions
 214  are declared static. We use the dummy __*_module_inline functions
 215  both to kill the warning and check the type of the init/cleanup
 216  function. */
 217
 218 /* Each module must use one module_init(), or one no_module_init */
 219 #define module_init(initfn)                                     \
 220         static inline initcall_t __inittest(void)               \
 221         { return initfn; }                                      \
 222         int init_module(void) __attribute__((alias(#initfn)));
 223
 224 /* This is only required if you want to be unloadable. */
 225 #define module_exit(exitfn)                                     \
 226         static inline exitcall_t __exittest(void)               \
 227         { return exitfn; }                                      \
 228         void cleanup_module(void) __attribute__((alias(#exitfn)));
 229
 230 #define __setup_param(str, unique_id, fn)       /* nothing */
 231 #define __setup_null_param(str, unique_id)      /* nothing */
 232 #define __setup(str, func)                      /* nothing */
 233 #define __obsolete_setup(str)                   /* nothing */
 234 #endif
 235
 236 /* Data marked not to be saved by software_suspend() */
 237 #define __nosavedata __attribute__ ((__section__ (".data.nosave")))
 238
 239 /* This means "can be init if no module support, otherwise module load
 240    may call it." */
 241 #ifdef CONFIG_MODULES
 242 #define __init_or_module
 243 #define __initdata_or_module
 244 #else
 245 #define __init_or_module __init
 246 #define __initdata_or_module __initdata
 247 #endif /*CONFIG_MODULES*/
 248
 249 #ifdef CONFIG_HOTPLUG
 250 #define __devinit
 251 #define __devinitdata
 252 #define __devexit
 253 #define __devexitdata
 254 #else
 255 #define __devinit __init
 256 #define __devinitdata __initdata
 257 #define __devexit __exit
 258 #define __devexitdata __exitdata
 259 #endif
 260
 261 #ifdef CONFIG_HOTPLUG_CPU
 262 #define __cpuinit
 263 #define __cpuinitdata
 264 #define __cpuexit
 265 #define __cpuexitdata
 266 #else
 267 #define __cpuinit       __init
 268 #define __cpuinitdata __initdata
 269 #define __cpuexit __exit
 270 #define __cpuexitdata   __exitdata
 271 #endif
 272
 273 #if defined(CONFIG_MEMORY_HOTPLUG) || defined(CONFIG_ACPI_HOTPLUG_MEMORY) \
 274         || defined(CONFIG_ACPI_HOTPLUG_MEMORY_MODULE)
 275 #define __meminit
 276 #define __meminitdata
 277 #define __memexit
 278 #define __memexitdata
 279 #else
 280 #define __meminit       __init
 281 #define __meminitdata __initdata
 282 #define __memexit __exit
 283 #define __memexitdata   __exitdata
 284 #endif
 285
 286 /* Functions marked as __devexit may be discarded at kernel link time, depending
 287    on config options.  Newer versions of binutils detect references from
 288    retained sections to discarded sections and flag an error.  Pointers to
 289    __devexit functions must use __devexit_p(function_name), the wrapper will
 290    insert either the function_name or NULL, depending on the config options.
 291  */
 292 #if defined(MODULE) || defined(CONFIG_HOTPLUG)
 293 #define __devexit_p(x) x
 294 #else
 295 #define __devexit_p(x) NULL
 296 #endif
 297
 298 #ifdef MODULE
 299 #define __exit_p(x) x
 300 #else
 301 #define __exit_p(x) NULL
 302 #endif
 303
 304 #endif /* _LINUX_INIT_H */