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 */
128