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