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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _LINUX_INIT_H
2#define _LINUX_INIT_H
3
4#include <linux/config.h>
5#include <linux/compiler.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 char linux_logo[] __initdata = { 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 __attribute__ ((__section__ (".init.text")))
45#define __initdata __attribute__ ((__section__ (".init.data")))
46#define __exitdata __attribute__ ((__section__(".exit.data")))
47#define __exit_call __attribute_used__ __attribute__ ((__section__ (".exitcall.exit")))
48
49#ifdef MODULE
50#define __exit __attribute__ ((__section__(".exit.text")))
51#else
52#define __exit __attribute_used__ __attribute__ ((__section__(".exit.text")))
53#endif
54
55/* For assembly routines */
56#define __INIT .section ".init.text","ax"
57#define __FINIT .previous
58#define __INITDATA .section ".init.data","aw"
59
60#ifndef __ASSEMBLY__
61/*
62 * Used for initialization calls..
63 */
64typedef int (*initcall_t)(void);
65typedef void (*exitcall_t)(void);
66
67extern initcall_t __con_initcall_start[], __con_initcall_end[];
68extern initcall_t __security_initcall_start[], __security_initcall_end[];
69
70/* Defined in init/main.c */
71extern char saved_command_line[];
72#endif
73
74#ifndef MODULE
75
76#ifndef __ASSEMBLY__
77
78/* initcalls are now grouped by functionality into separate
79 * subsections. Ordering inside the subsections is determined
80 * by link order.
81 * For backwards compatibility, initcall() puts the call in
82 * the device init subsection.
83 */
84
85#define __define_initcall(level,fn) \
86 static initcall_t __initcall_##fn __attribute_used__ \
87 __attribute__((__section__(".initcall" level ".init"))) = fn
88
89#define core_initcall(fn) __define_initcall("1",fn)
90#define postcore_initcall(fn) __define_initcall("2",fn)
91#define arch_initcall(fn) __define_initcall("3",fn)
92#define subsys_initcall(fn) __define_initcall("4",fn)
93#define fs_initcall(fn) __define_initcall("5",fn)
94#define device_initcall(fn) __define_initcall("6",fn)
95#define late_initcall(fn) __define_initcall("7",fn)
96
97#define __initcall(fn) device_initcall(fn)
98
99#define __exitcall(fn) \
100 static exitcall_t __exitcall_##fn __exit_call = fn
101
102#define console_initcall(fn) \
103 static initcall_t __initcall_##fn \
104 __attribute_used__ __attribute__((__section__(".con_initcall.init")))=fn
105
106#define security_initcall(fn) \
107 static initcall_t __initcall_##fn \
108 __attribute_used__ __attribute__((__section__(".security_initcall.init"))) = fn
109
110struct obs_kernel_param {
111 const char *str;
112 int (*setup_func)(char *);
113 int early;
114};
115
116/*
117 * Only for really core code. See moduleparam.h for the normal way.
118 *
119 * Force the alignment so the compiler doesn't space elements of the
120 * obs_kernel_param "array" too far apart in .init.setup.
121 */
122#define __setup_param(str, unique_id, fn, early) \
123 static char __setup_str_##unique_id[] __initdata = str; \
124 static struct obs_kernel_param __setup_##unique_id \
125 __attribute_used__ \
126 __attribute__((__section__(".init.setup"))) \
127 __attribute__((aligned((sizeof(long))))) \
128 = { __setup_str_##unique_id, fn, early }
129
130#define __setup_null_param(str, unique_id) \
131 __setup_param(str, unique_id, NULL, 0)
132
133#define __setup(str, fn) \
134 __setup_param(str, fn, fn, 0)
135
136#define __obsolete_setup(str) \
137 __setup_null_param(str, __LINE__)
138
139/* NOTE: fn is as per module_param, not __setup! Emits warning if fn
140 * returns non-zero. */
141#define early_param(str, fn) \
142 __setup_param(str, fn, fn, 1)
143
144/* Relies on saved_command_line being set */
145void __init parse_early_param(void);
146#endif /* __ASSEMBLY__ */
147
148/**
149 * module_init() - driver initialization entry point
150 * @x: function to be run at kernel boot time or module insertion
151 *
152 * module_init() will either be called during do_initcalls (if
153 * builtin) or at module insertion time (if a module). There can only
154 * be one per module.
155 */
156#define module_init(x) __initcall(x);
157
158/**
159 * module_exit() - driver exit entry point
160 * @x: function to be run when driver is removed
161 *
162 * module_exit() will wrap the driver clean-up code
163 * with cleanup_module() when used with rmmod when
164 * the driver is a module. If the driver is statically
165 * compiled into the kernel, module_exit() has no effect.
166 * There can only be one per module.
167 */
168#define module_exit(x) __exitcall(x);
169
170#else /* MODULE */
171
172/* Don't use these in modules, but some people do... */
173#define core_initcall(fn) module_init(fn)
174#define postcore_initcall(fn) module_init(fn)
175#define arch_initcall(fn) module_init(fn)
176#define subsys_initcall(fn) module_init(fn)
177#define fs_initcall(fn) module_init(fn)
178#define device_initcall(fn) module_init(fn)
179#define late_initcall(fn) module_init(fn)
180
181#define security_initcall(fn) module_init(fn)
182
183/* These macros create a dummy inline: gcc 2.9x does not count alias
184 as usage, hence the `unused function' warning when __init functions
185 are declared static. We use the dummy __*_module_inline functions
186 both to kill the warning and check the type of the init/cleanup
187 function. */
188
189/* Each module must use one module_init(), or one no_module_init */
190#define module_init(initfn) \
191 static inline initcall_t __inittest(void) \
192 { return initfn; } \
193 int init_module(void) __attribute__((alias(#initfn)));
194
195/* This is only required if you want to be unloadable. */
196#define module_exit(exitfn) \
197 static inline exitcall_t __exittest(void) \
198 { return exitfn; } \
199 void cleanup_module(void) __attribute__((alias(#exitfn)));
200
201#define __setup_param(str, unique_id, fn) /* nothing */
202#define __setup_null_param(str, unique_id) /* nothing */
203#define __setup(str, func) /* nothing */
204#define __obsolete_setup(str) /* nothing */
205#endif
206
207/* Data marked not to be saved by software_suspend() */
208#define __nosavedata __attribute__ ((__section__ (".data.nosave")))
209
210/* This means "can be init if no module support, otherwise module load
211 may call it." */
212#ifdef CONFIG_MODULES
213#define __init_or_module
214#define __initdata_or_module
215#else
216#define __init_or_module __init
217#define __initdata_or_module __initdata
218#endif /*CONFIG_MODULES*/
219
220#ifdef CONFIG_HOTPLUG
221#define __devinit
222#define __devinitdata
223#define __devexit
224#define __devexitdata
225#else
226#define __devinit __init
227#define __devinitdata __initdata
228#define __devexit __exit
229#define __devexitdata __exitdata
230#endif
231
232/* Functions marked as __devexit may be discarded at kernel link time, depending
233 on config options. Newer versions of binutils detect references from
234 retained sections to discarded sections and flag an error. Pointers to
235 __devexit functions must use __devexit_p(function_name), the wrapper will
236 insert either the function_name or NULL, depending on the config options.
237 */
238#if defined(MODULE) || defined(CONFIG_HOTPLUG)
239#define __devexit_p(x) x
240#else
241#define __devexit_p(x) NULL
242#endif
243
244#ifdef MODULE
245#define __exit_p(x) x
246#else
247#define __exit_p(x) NULL
248#endif
249
250#endif /* _LINUX_INIT_H */