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          __section(.init.text) __cold
  44 #define __initdata      __section(.init.data)
  45 <<<<<<< HEAD:include/linux/init.h
  46 =======
  47 #define __initconst     __section(.init.rodata)
  48 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:include/linux/init.h
  49 #define __exitdata      __section(.exit.data)
  50 #define __exit_call     __used __section(.exitcall.exit)
  51
  52 /* modpost check for section mismatches during the kernel build.
  53  * A section mismatch happens when there are references from a
  54  * code or data section to an init section (both code or data).
  55  * The init sections are (for most archs) discarded by the kernel
  56  * when early init has completed so all such references are potential bugs.
  57  * For exit sections the same issue exists.
  58  * The following markers are used for the cases where the reference to
  59  * the *init / *exit section (code or data) is valid and will teach
  60  * modpost not to issue a warning.
  61  * The markers follow same syntax rules as __init / __initdata. */
  62 #define __ref            __section(.ref.text) noinline
  63 #define __refdata        __section(.ref.data)
  64 #define __refconst       __section(.ref.rodata)
  65
  66 /* backward compatibility note
  67  *  A few places hardcode the old section names:
  68  *  .text.init.refok
  69  *  .data.init.refok
  70  *  .exit.text.refok
  71  *  They should be converted to use the defines from this file
  72  */
  73
  74 /* compatibility defines */
  75 #define __init_refok     __ref
  76 #define __initdata_refok __refdata
  77 #define __exit_refok     __ref
  78
  79
  80 #ifdef MODULE
  81 #define __exitused
  82 #else
  83 #define __exitused  __used
  84 #endif
  85
  86 #define __exit          __section(.exit.text) __exitused __cold
  87
  88 /* Used for HOTPLUG */
  89 #define __devinit        __section(.devinit.text) __cold
  90 #define __devinitdata    __section(.devinit.data)
  91 #define __devinitconst   __section(.devinit.rodata)
  92 #define __devexit        __section(.devexit.text) __exitused __cold
  93 #define __devexitdata    __section(.devexit.data)
  94 #define __devexitconst   __section(.devexit.rodata)
  95
  96 /* Used for HOTPLUG_CPU */
  97 #define __cpuinit        __section(.cpuinit.text) __cold
  98 #define __cpuinitdata    __section(.cpuinit.data)
  99 #define __cpuinitconst   __section(.cpuinit.rodata)
 100 #define __cpuexit        __section(.cpuexit.text) __exitused __cold
 101 #define __cpuexitdata    __section(.cpuexit.data)
 102 #define __cpuexitconst   __section(.cpuexit.rodata)
 103
 104 /* Used for MEMORY_HOTPLUG */
 105 #define __meminit        __section(.meminit.text) __cold
 106 #define __meminitdata    __section(.meminit.data)
 107 #define __meminitconst   __section(.meminit.rodata)
 108 #define __memexit        __section(.memexit.text) __exitused __cold
 109 #define __memexitdata    __section(.memexit.data)
 110 #define __memexitconst   __section(.memexit.rodata)
 111
 112 /* For assembly routines */
 113 <<<<<<< HEAD:include/linux/init.h
 114 =======
 115 #define __HEAD          .section        ".head.text","ax"
 116 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:include/linux/init.h
 117 #define __INIT          .section        ".init.text","ax"
 118 #define __FINIT         .previous
 119
 120 #define __INITDATA      .section        ".init.data","aw"
 121 #define __FINITDATA     .previous
 122
 123 #define __DEVINIT        .section       ".devinit.text", "ax"
 124 #define __DEVINITDATA    .section       ".devinit.data", "aw"
 125
 126 #define __CPUINIT        .section       ".cpuinit.text", "ax"
 127 #define __CPUINITDATA    .section       ".cpuinit.data", "aw"
 128
 129 #define __MEMINIT        .section       ".meminit.text", "ax"
 130 #define __MEMINITDATA    .section       ".meminit.data", "aw"
 131
 132 /* silence warnings when references are OK */
 133 #define __REF            .section       ".ref.text", "ax"
 134 #define __REFDATA        .section       ".ref.data", "aw"
 135 #define __REFCONST       .section       ".ref.rodata", "aw"
 136
 137 #ifndef __ASSEMBLY__
 138 /*
 139  * Used for initialization calls..
 140  */
 141 typedef int (*initcall_t)(void);
 142 typedef void (*exitcall_t)(void);
 143
 144 extern initcall_t __con_initcall_start[], __con_initcall_end[];
 145 extern initcall_t __security_initcall_start[], __security_initcall_end[];
 146
 147 /* Defined in init/main.c */
 148 extern char __initdata boot_command_line[];
 149 extern char *saved_command_line;
 150 extern unsigned int reset_devices;
 151
 152 /* used by init/main.c */
 153 void setup_arch(char **);
 154 void prepare_namespace(void);
 155
 156 #endif
 157
 158 #ifndef MODULE
 159
 160 #ifndef __ASSEMBLY__
 161
 162 /* initcalls are now grouped by functionality into separate
 163  * subsections. Ordering inside the subsections is determined
 164  * by link order.
 165  * For backwards compatibility, initcall() puts the call in
 166  * the device init subsection.
 167  *
 168  * The `id' arg to __define_initcall() is needed so that multiple initcalls
 169  * can point at the same handler without causing duplicate-symbol build errors.
 170  */
 171
 172 #define __define_initcall(level,fn,id) \
 173         static initcall_t __initcall_##fn##id __used \
 174         __attribute__((__section__(".initcall" level ".init"))) = fn
 175
 176 /*
 177  * A "pure" initcall has no dependencies on anything else, and purely
 178  * initializes variables that couldn't be statically initialized.
 179  *
 180  * This only exists for built-in code, not for modules.
 181  */
 182 #define pure_initcall(fn)               __define_initcall("0",fn,0)
 183
 184 #define core_initcall(fn)               __define_initcall("1",fn,1)
 185 #define core_initcall_sync(fn)          __define_initcall("1s",fn,1s)
 186 #define postcore_initcall(fn)           __define_initcall("2",fn,2)
 187 #define postcore_initcall_sync(fn)      __define_initcall("2s",fn,2s)
 188 #define arch_initcall(fn)               __define_initcall("3",fn,3)
 189 #define arch_initcall_sync(fn)          __define_initcall("3s",fn,3s)
 190 #define subsys_initcall(fn)             __define_initcall("4",fn,4)
 191 #define subsys_initcall_sync(fn)        __define_initcall("4s",fn,4s)
 192 #define fs_initcall(fn)                 __define_initcall("5",fn,5)
 193 #define fs_initcall_sync(fn)            __define_initcall("5s",fn,5s)
 194 #define rootfs_initcall(fn)             __define_initcall("rootfs",fn,rootfs)
 195 #define device_initcall(fn)             __define_initcall("6",fn,6)
 196 #define device_initcall_sync(fn)        __define_initcall("6s",fn,6s)
 197 #define late_initcall(fn)               __define_initcall("7",fn,7)
 198 #define late_initcall_sync(fn)          __define_initcall("7s",fn,7s)
 199
 200 #define __initcall(fn) device_initcall(fn)
 201
 202 #define __exitcall(fn) \
 203         static exitcall_t __exitcall_##fn __exit_call = fn
 204
 205 #define console_initcall(fn) \
 206         static initcall_t __initcall_##fn \
 207         __used __section(.con_initcall.init) = fn
 208
 209 #define security_initcall(fn) \
 210         static initcall_t __initcall_##fn \
 211         __used __section(.security_initcall.init) = fn
 212
 213 struct obs_kernel_param {
 214         const char *str;
 215         int (*setup_func)(char *);
 216         int early;
 217 };
 218
 219 /*
 220  * Only for really core code.  See moduleparam.h for the normal way.
 221  *
 222  * Force the alignment so the compiler doesn't space elements of the
 223  * obs_kernel_param "array" too far apart in .init.setup.
 224  */
 225 #define __setup_param(str, unique_id, fn, early)                        \
 226         static char __setup_str_##unique_id[] __initdata __aligned(1) = str; \
 227         static struct obs_kernel_param __setup_##unique_id      \
 228                 __used __section(.init.setup)                   \
 229                 __attribute__((aligned((sizeof(long)))))        \
 230                 = { __setup_str_##unique_id, fn, early }
 231
 232 #define __setup_null_param(str, unique_id)                      \
 233         __setup_param(str, unique_id, NULL, 0)
 234
 235 #define __setup(str, fn)                                        \
 236         __setup_param(str, fn, fn, 0)
 237
 238 /* NOTE: fn is as per module_param, not __setup!  Emits warning if fn
 239  * returns non-zero. */
 240 #define early_param(str, fn)                                    \
 241         __setup_param(str, fn, fn, 1)
 242
 243 /* Relies on boot_command_line being set */
 244 void __init parse_early_param(void);
 245 #endif /* __ASSEMBLY__ */
 246
 247 /**
 248  * module_init() - driver initialization entry point
 249  * @x: function to be run at kernel boot time or module insertion
 250  *
 251  * module_init() will either be called during do_initcalls() (if
 252  * builtin) or at module insertion time (if a module).  There can only
 253  * be one per module.
 254  */
 255 #define module_init(x)  __initcall(x);
 256
 257 /**
 258  * module_exit() - driver exit entry point
 259  * @x: function to be run when driver is removed
 260  *
 261  * module_exit() will wrap the driver clean-up code
 262  * with cleanup_module() when used with rmmod when
 263  * the driver is a module.  If the driver is statically
 264  * compiled into the kernel, module_exit() has no effect.
 265  * There can only be one per module.
 266  */
 267 #define module_exit(x)  __exitcall(x);
 268
 269 #else /* MODULE */
 270
 271 /* Don't use these in modules, but some people do... */
 272 #define core_initcall(fn)               module_init(fn)
 273 #define postcore_initcall(fn)           module_init(fn)
 274 #define arch_initcall(fn)               module_init(fn)
 275 #define subsys_initcall(fn)             module_init(fn)
 276 #define fs_initcall(fn)                 module_init(fn)
 277 #define device_initcall(fn)             module_init(fn)
 278 #define late_initcall(fn)               module_init(fn)
 279
 280 #define security_initcall(fn)           module_init(fn)
 281
 282 /* These macros create a dummy inline: gcc 2.9x does not count alias
 283  as usage, hence the `unused function' warning when __init functions
 284  are declared static. We use the dummy __*_module_inline functions
 285  both to kill the warning and check the type of the init/cleanup
 286  function. */
 287
 288 /* Each module must use one module_init(), or one no_module_init */
 289 #define module_init(initfn)                                     \
 290         static inline initcall_t __inittest(void)               \
 291         { return initfn; }                                      \
 292         int init_module(void) __attribute__((alias(#initfn)));
 293
 294 /* This is only required if you want to be unloadable. */
 295 #define module_exit(exitfn)                                     \
 296         static inline exitcall_t __exittest(void)               \
 297         { return exitfn; }                                      \
 298         void cleanup_module(void) __attribute__((alias(#exitfn)));
 299
 300 #define __setup_param(str, unique_id, fn)       /* nothing */
 301 #define __setup_null_param(str, unique_id)      /* nothing */
 302 #define __setup(str, func)                      /* nothing */
 303 #endif
 304
 305 /* Data marked not to be saved by software suspend */
 306 #define __nosavedata __section(.data.nosave)
 307
 308 /* This means "can be init if no module support, otherwise module load
 309    may call it." */
 310 #ifdef CONFIG_MODULES
 311 #define __init_or_module
 312 #define __initdata_or_module
 313 #else
 314 #define __init_or_module __init
 315 #define __initdata_or_module __initdata
 316 #endif /*CONFIG_MODULES*/
 317
 318 /* Functions marked as __devexit may be discarded at kernel link time, depending
 319    on config options.  Newer versions of binutils detect references from
 320    retained sections to discarded sections and flag an error.  Pointers to
 321    __devexit functions must use __devexit_p(function_name), the wrapper will
 322    insert either the function_name or NULL, depending on the config options.
 323  */
 324 #if defined(MODULE) || defined(CONFIG_HOTPLUG)
 325 #define __devexit_p(x) x
 326 #else
 327 #define __devexit_p(x) NULL
 328 #endif
 329
 330 #ifdef MODULE
 331 #define __exit_p(x) x
 332 #else
 333 #define __exit_p(x) NULL
 334 #endif
 335
 336 #endif /* _LINUX_INIT_H */