arch/um/include/shared/init.h

   1 #ifndef _LINUX_UML_INIT_H
   2 #define _LINUX_UML_INIT_H
   3
   4 /* These macros are used to mark some functions or
   5  * initialized data (doesn't apply to uninitialized data)
   6  * as `initialization' functions. The kernel can take this
   7  * as hint that the function is used only during the initialization
   8  * phase and free up used memory resources after
   9  *
  10  * Usage:
  11  * For functions:
  12  *
  13  * You should add __init immediately before the function name, like:
  14  *
  15  * static void __init initme(int x, int y)
  16  * {
  17  *    extern int z; z = x * y;
  18  * }
  19  *
  20  * If the function has a prototype somewhere, you can also add
  21  * __init between closing brace of the prototype and semicolon:
  22  *
  23  * extern int initialize_foobar_device(int, int, int) __init;
  24  *
  25  * For initialized data:
  26  * You should insert __initdata between the variable name and equal
  27  * sign followed by value, e.g.:
  28  *
  29  * static int init_variable __initdata = 0;
  30  * static const char linux_logo[] __initconst = { 0x32, 0x36, ... };
  31  *
  32  * Don't forget to initialize data not at file scope, i.e. within a function,
  33  * as gcc otherwise puts the data into the bss section and not into the init
  34  * section.
  35  *
  36  * Also note, that this data cannot be "const".
  37  */
  38
  39 #ifndef _LINUX_INIT_H
  40 typedef int (*initcall_t)(void);
  41 typedef void (*exitcall_t)(void);
  42
  43 #ifndef __KERNEL__
  44 #ifndef __section
  45 # define __section(S) __attribute__ ((__section__(#S)))
  46 #endif
  47
  48 #if __GNUC__ == 3
  49
  50 #if __GNUC_MINOR__ >= 3
  51 # define __used                 __attribute__((__used__))
  52 #else
  53 # define __used                 __attribute__((__unused__))
  54 #endif
  55
  56 #else
  57 #if __GNUC__ == 4
  58 # define __used                 __attribute__((__used__))
  59 #endif
  60 #endif
  61
  62 #else
  63 #include <linux/compiler.h>
  64 #endif
  65 /* These are for everybody (although not all archs will actually
  66    discard it in modules) */
  67 #define __init          __section(.init.text)
  68 #define __initdata      __section(.init.data)
  69 #define __exitdata      __section(.exit.data)
  70 #define __exit_call     __used __section(.exitcall.exit)
  71
  72 #ifdef MODULE
  73 #define __exit          __section(.exit.text)
  74 #else
  75 #define __exit          __used __section(.exit.text)
  76 #endif
  77
  78 #endif
  79
  80 #ifndef MODULE
  81 struct uml_param {
  82         const char *str;
  83         int (*setup_func)(char *, int *);
  84 };
  85
  86 extern initcall_t __uml_initcall_start, __uml_initcall_end;
  87 extern initcall_t __uml_postsetup_start, __uml_postsetup_end;
  88 extern const char *__uml_help_start, *__uml_help_end;
  89 #endif
  90
  91 #define __uml_initcall(fn)                                              \
  92         static initcall_t __uml_initcall_##fn __uml_init_call = fn
  93
  94 #define __uml_exitcall(fn)                                              \
  95         static exitcall_t __uml_exitcall_##fn __uml_exit_call = fn
  96
  97 extern struct uml_param __uml_setup_start, __uml_setup_end;
  98
  99 #define __uml_postsetup(fn)                                             \
 100         static initcall_t __uml_postsetup_##fn __uml_postsetup_call = fn
 101
 102 #define __non_empty_string(dummyname,string)                            \
 103         struct __uml_non_empty_string_struct_##dummyname                \
 104         {                                                               \
 105                 char _string[sizeof(string)-2];                         \
 106         }
 107
 108 #ifndef MODULE
 109 #define __uml_setup(str, fn, help...)                                   \
 110         __non_empty_string(fn ##_setup, str);                           \
 111         __uml_help(fn, help);                                           \
 112         static char __uml_setup_str_##fn[] __initdata = str;            \
 113         static struct uml_param __uml_setup_##fn __uml_init_setup = { __uml_setup_str_##fn, fn }
 114 #else
 115 #define __uml_setup(str, fn, help...)                                   \
 116
 117 #endif
 118
 119 #define __uml_help(fn, help...)                                         \
 120         __non_empty_string(fn ##__help, help);                          \
 121         static char __uml_help_str_##fn[] __initdata = help;            \
 122         static const char *__uml_help_##fn __uml_setup_help = __uml_help_str_##fn
 123
 124 /*
 125  * Mark functions and data as being only used at initialization
 126  * or exit time.
 127  */
 128 #define __uml_init_setup        __used __section(.uml.setup.init)
 129 #define __uml_setup_help        __used __section(.uml.help.init)
 130 #define __uml_init_call         __used __section(.uml.initcall.init)
 131 #define __uml_postsetup_call    __used __section(.uml.postsetup.init)
 132 #define __uml_exit_call         __used __section(.uml.exitcall.exit)
 133
 134 #ifndef __KERNEL__
 135
 136 #define __define_initcall(level,fn) \
 137         static initcall_t __initcall_##fn __used \
 138         __attribute__((__section__(".initcall" level ".init"))) = fn
 139
 140 /* Userspace initcalls shouldn't depend on anything in the kernel, so we'll
 141  * make them run first.
 142  */
 143 #define __initcall(fn) __define_initcall("1", fn)
 144
 145 #define __exitcall(fn) static exitcall_t __exitcall_##fn __exit_call = fn
 146
 147 #define __init_call     __used __section(.initcall.init)
 148
 149 #endif
 150
 151 #endif /* _LINUX_UML_INIT_H */