File: /Users/paulross/dev/linux/linux-3.13/include/linux/init.h

Green shading in the line number column means the source is part of the translation unit, red means it is conditionally excluded. Highlighted line numbers link to the translation unit page. Highlighted macros link to the macro page.

       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 or __initconst between the variable name
      30:  * and equal 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: 
      40: /* These are for everybody (although not all archs will actually
      41:    discard it in modules) */
      42: #define __init        __section(.init.text) __cold notrace
      43: #define __initdata    __section(.init.data)
      44: #define __initconst    __constsection(.init.rodata)
      45: #define __exitdata    __section(.exit.data)
      46: #define __exit_call    __used __section(.exitcall.exit)
      47: 
      48: /*
      49:  * Some architecture have tool chains which do not handle rodata attributes
      50:  * correctly. For those disable special sections for const, so that other
      51:  * architectures can annotate correctly.
      52:  */
      53: #ifdef CONFIG_BROKEN_RODATA
      54: #define __constsection(x)
      55: #else
      56: #define __constsection(x) __section(x)
      57: #endif
      58: 
      59: /*
      60:  * modpost check for section mismatches during the kernel build.
      61:  * A section mismatch happens when there are references from a
      62:  * code or data section to an init section (both code or data).
      63:  * The init sections are (for most archs) discarded by the kernel
      64:  * when early init has completed so all such references are potential bugs.
      65:  * For exit sections the same issue exists.
      66:  *
      67:  * The following markers are used for the cases where the reference to
      68:  * the *init / *exit section (code or data) is valid and will teach
      69:  * modpost not to issue a warning.  Intended semantics is that a code or
      70:  * data tagged __ref* can reference code or data from init section without
      71:  * producing a warning (of course, no warning does not mean code is
      72:  * correct, so optimally document why the __ref is needed and why it's OK).
      73:  *
      74:  * The markers follow same syntax rules as __init / __initdata.
      75:  */
      76: #define __ref            __section(.ref.text) noinline
      77: #define __refdata        __section(.ref.data)
      78: #define __refconst       __constsection(.ref.rodata)
      79: 
      80: /* compatibility defines */
      81: #define __init_refok     __ref
      82: #define __initdata_refok __refdata
      83: #define __exit_refok     __ref
      84: 
      85: 
      86: #ifdef MODULE
      87: #define __exitused
      88: #else
      89: #define __exitused  __used
      90: #endif
      91: 
      92: #define __exit          __section(.exit.text) __exitused __cold notrace
      93: 
      94: /* temporary, until all users are removed */
      95: #define __cpuinit
      96: #define __cpuinitdata
      97: #define __cpuinitconst
      98: #define __cpuexit
      99: #define __cpuexitdata
     100: #define __cpuexitconst
     101: 
     102: /* Used for MEMORY_HOTPLUG */
     103: #define __meminit        __section(.meminit.text) __cold notrace
     104: #define __meminitdata    __section(.meminit.data)
     105: #define __meminitconst   __constsection(.meminit.rodata)
     106: #define __memexit        __section(.memexit.text) __exitused __cold notrace
     107: #define __memexitdata    __section(.memexit.data)
     108: #define __memexitconst   __constsection(.memexit.rodata)
     109: 
     110: /* For assembly routines */
     111: #define __HEAD        .section    ".head.text","ax"
     112: #define __INIT        .section    ".init.text","ax"
     113: #define __FINIT        .previous
     114: 
     115: #define __INITDATA    .section    ".init.data","aw",%progbits
     116: #define __INITRODATA    .section    ".init.rodata","a",%progbits
     117: #define __FINITDATA    .previous
     118: 
     119: /* temporary, until all users are removed */
     120: #define __CPUINIT
     121: 
     122: #define __MEMINIT        .section    ".meminit.text", "ax"
     123: #define __MEMINITDATA    .section    ".meminit.data", "aw"
     124: #define __MEMINITRODATA  .section    ".meminit.rodata", "a"
     125: 
     126: /* silence warnings when references are OK */
     127: #define __REF            .section       ".ref.text", "ax"
     128: #define __REFDATA        .section       ".ref.data", "aw"
     129: #define __REFCONST       .section       ".ref.rodata", "a"
     130: 
     131: #ifndef __ASSEMBLY__
     132: /*
     133:  * Used for initialization calls..
     134:  */
     135: typedef int (*initcall_t)(void);
     136: typedef void (*exitcall_t)(void);
     137: 
     138: extern initcall_t __con_initcall_start[], __con_initcall_end[];
     139: extern initcall_t __security_initcall_start[], __security_initcall_end[];
     140: 
     141: /* Used for contructor calls. */
     142: typedef void (*ctor_fn_t)(void);
     143: 
     144: /* Defined in init/main.c */
     145: extern int do_one_initcall(initcall_t fn);
     146: extern char __initdata boot_command_line[];
     147: extern char *saved_command_line;
     148: extern unsigned int reset_devices;
     149: 
     150: /* used by init/main.c */
     151: void setup_arch(char **);
     152: void prepare_namespace(void);
     153: void __init load_default_modules(void);
     154: int __init init_rootfs(void);
     155: 
     156: extern void (*late_time_init)(void);
     157: 
     158: extern bool initcall_debug;
     159: 
     160: #endif
     161:   
     162: #ifndef MODULE
     163: 
     164: #ifndef __ASSEMBLY__
     165: 
     166: /* initcalls are now grouped by functionality into separate 
     167:  * subsections. Ordering inside the subsections is determined
     168:  * by link order. 
     169:  * For backwards compatibility, initcall() puts the call in 
     170:  * the device init subsection.
     171:  *
     172:  * The `id' arg to __define_initcall() is needed so that multiple initcalls
     173:  * can point at the same handler without causing duplicate-symbol build errors.
     174:  */
     175: 
     176: #define __define_initcall(fn, id) \
     177:     static initcall_t __initcall_##fn##id __used \
     178:     __attribute__((__section__(".initcall" #id ".init"))) = fn
     179: 
     180: /*
     181:  * Early initcalls run before initializing SMP.
     182:  *
     183:  * Only for built-in code, not modules.
     184:  */
     185: #define early_initcall(fn)        __define_initcall(fn, early)
     186: 
     187: /*
     188:  * A "pure" initcall has no dependencies on anything else, and purely
     189:  * initializes variables that couldn't be statically initialized.
     190:  *
     191:  * This only exists for built-in code, not for modules.
     192:  * Keep main.c:initcall_level_names[] in sync.
     193:  */
     194: #define pure_initcall(fn)        __define_initcall(fn, 0)
     195: 
     196: #define core_initcall(fn)        __define_initcall(fn, 1)
     197: #define core_initcall_sync(fn)        __define_initcall(fn, 1s)
     198: #define postcore_initcall(fn)        __define_initcall(fn, 2)
     199: #define postcore_initcall_sync(fn)    __define_initcall(fn, 2s)
     200: #define arch_initcall(fn)        __define_initcall(fn, 3)
     201: #define arch_initcall_sync(fn)        __define_initcall(fn, 3s)
     202: #define subsys_initcall(fn)        __define_initcall(fn, 4)
     203: #define subsys_initcall_sync(fn)    __define_initcall(fn, 4s)
     204: #define fs_initcall(fn)            __define_initcall(fn, 5)
     205: #define fs_initcall_sync(fn)        __define_initcall(fn, 5s)
     206: #define rootfs_initcall(fn)        __define_initcall(fn, rootfs)
     207: #define device_initcall(fn)        __define_initcall(fn, 6)
     208: #define device_initcall_sync(fn)    __define_initcall(fn, 6s)
     209: #define late_initcall(fn)        __define_initcall(fn, 7)
     210: #define late_initcall_sync(fn)        __define_initcall(fn, 7s)
     211: 
     212: #define __initcall(fn) device_initcall(fn)
     213: 
     214: #define __exitcall(fn) \
     215:     static exitcall_t __exitcall_##fn __exit_call = fn
     216: 
     217: #define console_initcall(fn) \
     218:     static initcall_t __initcall_##fn \
     219:     __used __section(.con_initcall.init) = fn
     220: 
     221: #define security_initcall(fn) \
     222:     static initcall_t __initcall_##fn \
     223:     __used __section(.security_initcall.init) = fn
     224: 
     225: struct obs_kernel_param {
     226:     const char *str;
     227:     int (*setup_func)(char *);
     228:     int early;
     229: };
     230: 
     231: /*
     232:  * Only for really core code.  See moduleparam.h for the normal way.
     233:  *
     234:  * Force the alignment so the compiler doesn't space elements of the
     235:  * obs_kernel_param "array" too far apart in .init.setup.
     236:  */
     237: #define __setup_param(str, unique_id, fn, early)            \
     238:     static const char __setup_str_##unique_id[] __initconst    \
     239:         __aligned(1) = str; \
     240:     static struct obs_kernel_param __setup_##unique_id    \
     241:         __used __section(.init.setup)            \
     242:         __attribute__((aligned((sizeof(long)))))    \
     243:         = { __setup_str_##unique_id, fn, early }
     244: 
     245: #define __setup(str, fn)                    \
     246:     __setup_param(str, fn, fn, 0)
     247: 
     248: /* NOTE: fn is as per module_param, not __setup!  Emits warning if fn
     249:  * returns non-zero. */
     250: #define early_param(str, fn)                    \
     251:     __setup_param(str, fn, fn, 1)
     252: 
     253: /* Relies on boot_command_line being set */
     254: void __init parse_early_param(void);
     255: void __init parse_early_options(char *cmdline);
     256: #endif /* __ASSEMBLY__ */
     257: 
     258: /**
     259:  * module_init() - driver initialization entry point
     260:  * @x: function to be run at kernel boot time or module insertion
     261:  * 
     262:  * module_init() will either be called during do_initcalls() (if
     263:  * builtin) or at module insertion time (if a module).  There can only
     264:  * be one per module.
     265:  */
     266: #define module_init(x)    __initcall(x);
     267: 
     268: /**
     269:  * module_exit() - driver exit entry point
     270:  * @x: function to be run when driver is removed
     271:  * 
     272:  * module_exit() will wrap the driver clean-up code
     273:  * with cleanup_module() when used with rmmod when
     274:  * the driver is a module.  If the driver is statically
     275:  * compiled into the kernel, module_exit() has no effect.
     276:  * There can only be one per module.
     277:  */
     278: #define module_exit(x)    __exitcall(x);
     279: 
     280: #else /* MODULE */
     281: 
     282: /* Don't use these in loadable modules, but some people do... */
     283: #define early_initcall(fn)        module_init(fn)
     284: #define core_initcall(fn)        module_init(fn)
     285: #define postcore_initcall(fn)        module_init(fn)
     286: #define arch_initcall(fn)        module_init(fn)
     287: #define subsys_initcall(fn)        module_init(fn)
     288: #define fs_initcall(fn)            module_init(fn)
     289: #define device_initcall(fn)        module_init(fn)
     290: #define late_initcall(fn)        module_init(fn)
     291: 
     292: #define security_initcall(fn)        module_init(fn)
     293: 
     294: /* Each module must use one module_init(). */
     295: #define module_init(initfn)                    \
     296:     static inline initcall_t __inittest(void)        \
     297:     { return initfn; }                    \
     298:     int init_module(void) __attribute__((alias(#initfn)));
     299: 
     300: /* This is only required if you want to be unloadable. */
     301: #define module_exit(exitfn)                    \
     302:     static inline exitcall_t __exittest(void)        \
     303:     { return exitfn; }                    \
     304:     void cleanup_module(void) __attribute__((alias(#exitfn)));
     305: 
     306: #define __setup_param(str, unique_id, fn)    /* nothing */
     307: #define __setup(str, func)             /* nothing */
     308: #endif
     309: 
     310: /* Data marked not to be saved by software suspend */
     311: #define __nosavedata __section(.data..nosave)
     312: 
     313: /* This means "can be init if no module support, otherwise module load
     314:    may call it." */
     315: #ifdef CONFIG_MODULES
     316: #define __init_or_module
     317: #define __initdata_or_module
     318: #define __initconst_or_module
     319: #define __INIT_OR_MODULE    .text
     320: #define __INITDATA_OR_MODULE    .data
     321: #define __INITRODATA_OR_MODULE    .section ".rodata","a",%progbits
     322: #else
     323: #define __init_or_module __init
     324: #define __initdata_or_module __initdata
     325: #define __initconst_or_module __initconst
     326: #define __INIT_OR_MODULE __INIT
     327: #define __INITDATA_OR_MODULE __INITDATA
     328: #define __INITRODATA_OR_MODULE __INITRODATA
     329: #endif /*CONFIG_MODULES*/
     330: 
     331: #ifdef MODULE
     332: #define __exit_p(x) x
     333: #else
     334: #define __exit_p(x) NULL
     335: #endif
     336: 
     337: #endif /* _LINUX_INIT_H */
     338: