include/linux/init.h

   1 #ifndef _LINUX_INIT_H
   2 #define _LINUX_INIT_H
   3
   4 #include <linux/compiler.h>
   5 #include <linux/types.h>
   6
   7 /* These macros are used to mark some functions or
   8  * initialized data (doesn't apply to uninitialized data)
   9  * as `initialization' functions. The kernel can take this
  10  * as hint that the function is used only during the initialization
  11  * phase and free up used memory resources after
  12  *
  13  * Usage:
  14  * For functions:
  15  *
  16  * You should add __init immediately before the function name, like:
  17  *
  18  * static void __init initme(int x, int y)
  19  * {
  20  *    extern int z; z = x * y;
  21  * }
  22  *
  23  * If the function has a prototype somewhere, you can also add
  24  * __init between closing brace of the prototype and semicolon:
  25  *
  26  * extern int initialize_foobar_device(int, int, int) __init;
  27  *
  28  * For initialized data:
  29  * You should insert __initdata between the variable name and equal
  30  * sign followed by value, e.g.:
  31  *
  32  * static int init_variable __initdata = 0;
  33  * static const char linux_logo[] __initconst = { 0x32, 0x36, ... };
  34  *
  35  * Don't forget to initialize data not at file scope, i.e. within a function,
  36  * as gcc otherwise puts the data into the bss section and not into the init
  37  * section.
  38  *
  39  * Also note, that this data cannot be "const".
  40  */
  41
  42 /* These are for everybody (although not all archs will actually
  43    discard it in modules) */
  44 #define __init          __section(.init.text) __cold notrace
  45 #define __initdata      __section(.init.data)
  46 #define __initconst     __constsection(.init.rodata)
  47 #define __exitdata      __section(.exit.data)
  48 #define __exit_call     __used __section(.exitcall.exit)
  49
  50 /*
  51  * Some architecture have tool chains which do not handle rodata attributes
  52  * correctly. For those disable special sections for const, so that other
  53  * architectures can annotate correctly.
  54  */
  55 #ifdef CONFIG_BROKEN_RODATA
  56 #define __constsection(x)
  57 #else
  58 #define __constsection(x) __section(x)
  59 #endif
  60
  61 /*
  62  * modpost check for section mismatches during the kernel build.
  63  * A section mismatch happens when there are references from a
  64  * code or data section to an init section (both code or data).
  65  * The init sections are (for most archs) discarded by the kernel
  66  * when early init has completed so all such references are potential bugs.
  67  * For exit sections the same issue exists.
  68  *
  69  * The following markers are used for the cases where the reference to
  70  * the *init / *exit section (code or data) is valid and will teach
  71  * modpost not to issue a warning.  Intended semantics is that a code or
  72  * data tagged __ref* can reference code or data from init section without
  73  * producing a warning (of course, no warning does not mean code is
  74  * correct, so optimally document why the __ref is needed and why it's OK).
  75  *
  76  * The markers follow same syntax rules as __init / __initdata.
  77  */
  78 #define __ref            __section(.ref.text) noinline
  79 #define __refdata        __section(.ref.data)
  80 #define __refconst       __constsection(.ref.rodata)
  81
  82 /* compatibility defines */
  83 #define __init_refok     __ref
  84 #define __initdata_refok __refdata
  85 #define __exit_refok     __ref
  86
  87
  88 #ifdef MODULE
  89 #define __exitused
  90 #else
  91 #define __exitused  __used
  92 #endif
  93
  94 #define __exit          __section(.exit.text) __exitused __cold notrace
  95
  96 /* temporary, until all users are removed */
  97 #define __cpuinit
  98 #define __cpuinitdata
  99 #define __cpuinitconst
 100 #define __cpuexit
 101 #define __cpuexitdata
 102 #define __cpuexitconst
 103
 104 /* Used for MEMORY_HOTPLUG */
 105 #define __meminit        __section(.meminit.text) __cold notrace
 106 #define __meminitdata    __section(.meminit.data)
 107 #define __meminitconst   __constsection(.meminit.rodata)
 108 #define __memexit        __section(.memexit.text) __exitused __cold notrace
 109 #define __memexitdata    __section(.memexit.data)
 110 #define __memexitconst   __constsection(.memexit.rodata)
 111
 112 /* For assembly routines */
 113 #define __HEAD          .section        ".head.text","ax"
 114 #define __INIT          .section        ".init.text","ax"
 115 #define __FINIT         .previous
 116
 117 #define __INITDATA      .section        ".init.data","aw",%progbits
 118 #define __INITRODATA    .section        ".init.rodata","a",%progbits
 119 #define __FINITDATA     .previous
 120
 121 /* temporary, until all users are removed */
 122 #define __CPUINIT
 123
 124 #define __MEMINIT        .section       ".meminit.text", "ax"
 125 #define __MEMINITDATA    .section       ".meminit.data", "aw"
 126 #define __MEMINITRODATA  .section       ".meminit.rodata", "a"
 127
 128 /* silence warnings when references are OK */
 129 #define __REF            .section       ".ref.text", "ax"
 130 #define __REFDATA        .section       ".ref.data", "aw"
 131 #define __REFCONST       .section       ".ref.rodata", "a"
 132
 133 #ifndef __ASSEMBLY__
 134 /*
 135  * Used for initialization calls..
 136  */
 137 typedef int (*initcall_t)(void);
 138 typedef void (*exitcall_t)(void);
 139
 140 extern initcall_t __con_initcall_start[], __con_initcall_end[];
 141 extern initcall_t __security_initcall_start[], __security_initcall_end[];
 142
 143 /* Used for contructor calls. */
 144 typedef void (*ctor_fn_t)(void);
 145
 146 /* Defined in init/main.c */
 147 extern int do_one_initcall(initcall_t fn);
 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 void __init load_default_modules(void);
 156
 157 extern void (*late_time_init)(void);
 158
 159 extern bool initcall_debug;
 160
 161 #endif
 162
 163 #ifndef MODULE
 164
 165 #ifndef __ASSEMBLY__
 166
 167 /* initcalls are now grouped by functionality into separate
 168  * subsections. Ordering inside the subsections is determined
 169  * by link order.
 170  * For backwards compatibility, initcall() puts the call in
 171  * the device init subsection.
 172  *
 173  * The `id' arg to __define_initcall() is needed so that multiple initcalls
 174  * can point at the same handler without causing duplicate-symbol build errors.
 175  */
 176
 177 #define __define_initcall(fn, id) \
 178         static initcall_t __initcall_##fn##id __used \
 179         __attribute__((__section__(".initcall" #id ".init"))) = fn
 180
 181 /*
 182  * Early initcalls run before initializing SMP.
 183  *
 184  * Only for built-in code, not modules.
 185  */
 186 #define early_initcall(fn)              __define_initcall(fn, early)
 187
 188 /*
 189  * A "pure" initcall has no dependencies on anything else, and purely
 190  * initializes variables that couldn't be statically initialized.
 191  *
 192  * This only exists for built-in code, not for modules.
 193  * Keep main.c:initcall_level_names[] in sync.
 194  */
 195 #define pure_initcall(fn)               __define_initcall(fn, 0)
 196
 197 #define core_initcall(fn)               __define_initcall(fn, 1)
 198 #define core_initcall_sync(fn)          __define_initcall(fn, 1s)
 199 #define postcore_initcall(fn)           __define_initcall(fn, 2)
 200 #define postcore_initcall_sync(fn)      __define_initcall(fn, 2s)
 201 #define arch_initcall(fn)               __define_initcall(fn, 3)
 202 #define arch_initcall_sync(fn)          __define_initcall(fn, 3s)
 203 #define subsys_initcall(fn)             __define_initcall(fn, 4)
 204 #define subsys_initcall_sync(fn)        __define_initcall(fn, 4s)
 205 #define fs_initcall(fn)                 __define_initcall(fn, 5)
 206 #define fs_initcall_sync(fn)            __define_initcall(fn, 5s)
 207 #define rootfs_initcall(fn)             __define_initcall(fn, rootfs)
 208 #define device_initcall(fn)             __define_initcall(fn, 6)
 209 #define device_initcall_sync(fn)        __define_initcall(fn, 6s)
 210 #define late_initcall(fn)               __define_initcall(fn, 7)
 211 #define late_initcall_sync(fn)          __define_initcall(fn, 7s)
 212
 213 #define __initcall(fn) device_initcall(fn)
 214
 215 #define __exitcall(fn) \
 216         static exitcall_t __exitcall_##fn __exit_call = fn
 217
 218 #define console_initcall(fn) \
 219         static initcall_t __initcall_##fn \
 220         __used __section(.con_initcall.init) = fn
 221
 222 #define security_initcall(fn) \
 223         static initcall_t __initcall_##fn \
 224         __used __section(.security_initcall.init) = fn
 225
 226 struct obs_kernel_param {
 227         const char *str;
 228         int (*setup_func)(char *);
 229         int early;
 230 };
 231
 232 /*
 233  * Only for really core code.  See moduleparam.h for the normal way.
 234  *
 235  * Force the alignment so the compiler doesn't space elements of the
 236  * obs_kernel_param "array" too far apart in .init.setup.
 237  */
 238 #define __setup_param(str, unique_id, fn, early)                        \
 239         static const char __setup_str_##unique_id[] __initconst \
 240                 __aligned(1) = str; \
 241         static struct obs_kernel_param __setup_##unique_id      \
 242                 __used __section(.init.setup)                   \
 243                 __attribute__((aligned((sizeof(long)))))        \
 244                 = { __setup_str_##unique_id, fn, early }
 245
 246 #define __setup(str, fn)                                        \
 247         __setup_param(str, fn, fn, 0)
 248
 249 /* NOTE: fn is as per module_param, not __setup!  Emits warning if fn
 250  * returns non-zero. */
 251 #define early_param(str, fn)                                    \
 252         __setup_param(str, fn, fn, 1)
 253
 254 /* Relies on boot_command_line being set */
 255 void __init parse_early_param(void);
 256 void __init parse_early_options(char *cmdline);
 257 #endif /* __ASSEMBLY__ */
 258
 259 /**
 260  * module_init() - driver initialization entry point
 261  * @x: function to be run at kernel boot time or module insertion
 262  *
 263  * module_init() will either be called during do_initcalls() (if
 264  * builtin) or at module insertion time (if a module).  There can only
 265  * be one per module.
 266  */
 267 #define module_init(x)  __initcall(x);
 268
 269 /**
 270  * module_exit() - driver exit entry point
 271  * @x: function to be run when driver is removed
 272  *
 273  * module_exit() will wrap the driver clean-up code
 274  * with cleanup_module() when used with rmmod when
 275  * the driver is a module.  If the driver is statically
 276  * compiled into the kernel, module_exit() has no effect.
 277  * There can only be one per module.
 278  */
 279 #define module_exit(x)  __exitcall(x);
 280
 281 #else /* MODULE */
 282
 283 /* Don't use these in loadable modules, but some people do... */
 284 #define early_initcall(fn)              module_init(fn)
 285 #define core_initcall(fn)               module_init(fn)
 286 #define postcore_initcall(fn)           module_init(fn)
 287 #define arch_initcall(fn)               module_init(fn)
 288 #define subsys_initcall(fn)             module_init(fn)
 289 #define fs_initcall(fn)                 module_init(fn)
 290 #define device_initcall(fn)             module_init(fn)
 291 #define late_initcall(fn)               module_init(fn)
 292
 293 #define security_initcall(fn)           module_init(fn)
 294
 295 /* Each module must use one module_init(). */
 296 #define module_init(initfn)                                     \
 297         static inline initcall_t __inittest(void)               \
 298         { return initfn; }                                      \
 299         int init_module(void) __attribute__((alias(#initfn)));
 300
 301 /* This is only required if you want to be unloadable. */
 302 #define module_exit(exitfn)                                     \
 303         static inline exitcall_t __exittest(void)               \
 304         { return exitfn; }                                      \
 305         void cleanup_module(void) __attribute__((alias(#exitfn)));
 306
 307 #define __setup_param(str, unique_id, fn)       /* nothing */
 308 #define __setup(str, func)                      /* nothing */
 309 #endif
 310
 311 /* Data marked not to be saved by software suspend */
 312 #define __nosavedata __section(.data..nosave)
 313
 314 /* This means "can be init if no module support, otherwise module load
 315    may call it." */
 316 #ifdef CONFIG_MODULES
 317 #define __init_or_module
 318 #define __initdata_or_module
 319 #define __initconst_or_module
 320 #define __INIT_OR_MODULE        .text
 321 #define __INITDATA_OR_MODULE    .data
 322 #define __INITRODATA_OR_MODULE  .section ".rodata","a",%progbits
 323 #else
 324 #define __init_or_module __init
 325 #define __initdata_or_module __initdata
 326 #define __initconst_or_module __initconst
 327 #define __INIT_OR_MODULE __INIT
 328 #define __INITDATA_OR_MODULE __INITDATA
 329 #define __INITRODATA_OR_MODULE __INITRODATA
 330 #endif /*CONFIG_MODULES*/
 331
 332 #ifdef MODULE
 333 #define __exit_p(x) x
 334 #else
 335 #define __exit_p(x) NULL
 336 #endif
 337
 338 #endif /* _LINUX_INIT_H */