arch/um/include/shared/init.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_UML_INIT_H
   3 #define _LINUX_UML_INIT_H
   4
   5 /* These macros are used to mark some functions or
   6  * initialized data (doesn't apply to uninitialized data)
   7  * as `initialization' functions. The kernel can take this
   8  * as hint that the function is used only during the initialization
   9  * phase and free up used memory resources after
  10  *
  11  * Usage:
  12  * For functions:
  13  *
  14  * You should add __init immediately before the function name, like:
  15  *
  16  * static void __init initme(int x, int y)
  17  * {
  18  *    extern int z; z = x * y;
  19  * }
  20  *
  21  * If the function has a prototype somewhere, you can also add
  22  * __init between closing brace of the prototype and semicolon:
  23  *
  24  * extern int initialize_foobar_device(int, int, int) __init;
  25  *
  26  * For initialized data:
  27  * You should insert __initdata between the variable name and equal
  28  * sign followed by value, e.g.:
  29  *
  30  * static int init_variable __initdata = 0;
  31  * static const char linux_logo[] __initconst = { 0x32, 0x36, ... };
  32  *
  33  * Don't forget to initialize data not at file scope, i.e. within a function,
  34  * as gcc otherwise puts the data into the bss section and not into the init
  35  * section.
  36  *
  37  * Also note, that this data cannot be "const".
  38  */
  39
  40 #ifndef _LINUX_INIT_H
  41 typedef int (*initcall_t)(void);
  42 typedef void (*exitcall_t)(void);
  43
  44 #include <linux/compiler_types.h>
  45
  46 /* These are for everybody (although not all archs will actually
  47    discard it in modules) */
  48 #define __init          __section(.init.text)
  49 #define __initdata      __section(.init.data)
  50 #define __exitdata      __section(.exit.data)
  51 #define __exit_call     __used __section(.exitcall.exit)
  52
  53 #ifdef MODULE
  54 #define __exit          __section(.exit.text)
  55 #else
  56 #define __exit          __used __section(.exit.text)
  57 #endif
  58
  59 #endif
  60
  61 #ifndef MODULE
  62 struct uml_param {
  63         const char *str;
  64         int (*setup_func)(char *, int *);
  65 };
  66
  67 extern initcall_t __uml_postsetup_start, __uml_postsetup_end;
  68 extern const char *__uml_help_start, *__uml_help_end;
  69 #endif
  70
  71 #define __uml_exitcall(fn)                                              \
  72         static exitcall_t __uml_exitcall_##fn __uml_exit_call = fn
  73
  74 extern struct uml_param __uml_setup_start, __uml_setup_end;
  75
  76 #define __uml_postsetup(fn)                                             \
  77         static initcall_t __uml_postsetup_##fn __uml_postsetup_call = fn
  78
  79 #define __non_empty_string(dummyname,string)                            \
  80         struct __uml_non_empty_string_struct_##dummyname                \
  81         {                                                               \
  82                 char _string[sizeof(string)-2];                         \
  83         }
  84
  85 #ifndef MODULE
  86 #define __uml_setup(str, fn, help...)                                   \
  87         __non_empty_string(fn ##_setup, str);                           \
  88         __uml_help(fn, help);                                           \
  89         static char __uml_setup_str_##fn[] __initdata = str;            \
  90         static struct uml_param __uml_setup_##fn __uml_init_setup = { __uml_setup_str_##fn, fn }
  91 #else
  92 #define __uml_setup(str, fn, help...)                                   \
  93
  94 #endif
  95
  96 #define __uml_help(fn, help...)                                         \
  97         __non_empty_string(fn ##__help, help);                          \
  98         static char __uml_help_str_##fn[] __initdata = help;            \
  99         static const char *__uml_help_##fn __uml_setup_help = __uml_help_str_##fn
 100
 101 /*
 102  * Mark functions and data as being only used at initialization
 103  * or exit time.
 104  */
 105 #define __uml_init_setup        __used __section(.uml.setup.init)
 106 #define __uml_setup_help        __used __section(.uml.help.init)
 107 #define __uml_postsetup_call    __used __section(.uml.postsetup.init)
 108 #define __uml_exit_call         __used __section(.uml.exitcall.exit)
 109
 110 #ifdef __UM_HOST__
 111
 112 #define __define_initcall(level,fn) \
 113         static initcall_t __initcall_##fn __used \
 114         __attribute__((__section__(".initcall" level ".init"))) = fn
 115
 116 /* Userspace initcalls shouldn't depend on anything in the kernel, so we'll
 117  * make them run first.
 118  */
 119 #define __initcall(fn) __define_initcall("1", fn)
 120
 121 #define __exitcall(fn) static exitcall_t __exitcall_##fn __exit_call = fn
 122
 123 #define __init_call     __used __section(.initcall.init)
 124
 125 #endif
 126
 127 #endif /* _LINUX_UML_INIT_H */