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