aboutsummaryrefslogtreecommitdiffstats
path: root/include/linux/init.h
blob: c65f5107d512c4a2df0e3373616772849c9e383b (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
#ifndef _LINUX_INIT_H
#define _LINUX_INIT_H

#include <linux/compiler.h>

/* These macros are used to mark some functions or 
 * initialized data (doesn't apply to uninitialized data)
 * as `initialization' functions. The kernel can take this
 * as hint that the function is used only during the initialization
 * phase and free up used memory resources after
 *
 * Usage:
 * For functions:
 * 
 * You should add __init immediately before the function name, like:
 *
 * static void __init initme(int x, int y)
 * {
 *    extern int z; z = x * y;
 * }
 *
 * If the function has a prototype somewhere, you can also add
 * __init between closing brace of the prototype and semicolon:
 *
 * extern int initialize_foobar_device(int, int, int) __init;
 *
 * For initialized data:
 * You should insert __initdata between the variable name and equal
 * sign followed by value, e.g.:
 *
 * static int init_variable __initdata = 0;
 * static char linux_logo[] __initdata = { 0x32, 0x36, ... };
 *
 * Don't forget to initialize data not at file scope, i.e. within a function,
 * as gcc otherwise puts the data into the bss section and not into the init
 * section.
 * 
 * Also note, that this data cannot be "const".
 */

/* These are for everybody (although not all archs will actually
   discard it in modules) */
#define __init		__attribute__ ((__section__ (".init.text")))
#define __initdata	__attribute__ ((__section__ (".init.data")))
#define __exitdata	__attribute__ ((__section__(".exit.data")))
#define __exit_call	__attribute_used__ __attribute__ ((__section__ (".exitcall.exit")))

#ifdef MODULE
#define __exit		__attribute__ ((__section__(".exit.text")))
#else
#define __exit		__attribute_used__ __attribute__ ((__section__(".exit.text")))
#endif

/* For assembly routines */
#define __INIT		.section	".init.text","ax"
#define __FINIT		.previous
#define __INITDATA	.section	".init.data","aw"

#ifndef __ASSEMBLY__
/*
 * Used for initialization calls..
 */
typedef int (*initcall_t)(void);
typedef void (*exitcall_t)(void);

extern initcall_t __con_initcall_start[], __con_initcall_end[];
extern initcall_t __security_initcall_start[], __security_initcall_end[];

/* Defined in init/main.c */
extern char saved_command_line[];
extern unsigned int reset_devices;

/* used by init/main.c */
extern void setup_arch(char **);

#endif
  
#ifndef MODULE

#ifndef __ASSEMBLY__

/* initcalls are now grouped by functionality into separate 
 * subsections. Ordering inside the subsections is determined
 * by link order. 
 * For backwards compatibility, initcall() puts the call in 
 * the device init subsection.
 *
 * The `id' arg to __define_initcall() is needed so that multiple initcalls
 * can point at the same handler without causing duplicate-symbol build errors.
 */

#define __define_initcall(level,fn,id) \
	static initcall_t __initcall_##fn##id __attribute_used__ \
	__attribute__((__section__(".initcall" level ".init"))) = fn

/*
 * A "pure" initcall has no dependencies on anything else, and purely
 * initializes variables that couldn't be statically initialized.
 *
 * This only exists for built-in code, not for modules.
 */
#define pure_initcall(fn)		__define_initcall("0",fn,1)

#define core_initcall(fn)		__define_initcall("1",fn,1)
#define core_initcall_sync(fn)		__define_initcall("1s",fn,1s)
#define postcore_initcall(fn)		__define_initcall("2",fn,2)
#define postcore_initcall_sync(fn)	__define_initcall("2s",fn,2s)
#define arch_initcall(fn)		__define_initcall("3",fn,3)
#define arch_initcall_sync(fn)		__define_initcall("3s",fn,3s)
#define subsys_initcall(fn)		__define_initcall("4",fn,4)
#define subsys_initcall_sync(fn)	__define_initcall("4s",fn,4s)
#define fs_initcall(fn)			__define_initcall("5",fn,5)
#define fs_initcall_sync(fn)		__define_initcall("5s",fn,5s)
#define rootfs_initcall(fn)		__define_initcall("rootfs",fn,rootfs)
#define device_initcall(fn)		__define_initcall("6",fn,6)
#define device_initcall_sync(fn)	__define_initcall("6s",fn,6s)
#define late_initcall(fn)		__define_initcall("7",fn,7)
#define late_initcall_sync(fn)		__define_initcall("7s",fn,7s)

#define __initcall(fn) device_initcall(fn)

#define __exitcall(fn) \
	static exitcall_t __exitcall_##fn __exit_call = fn

#define console_initcall(fn) \
	static initcall_t __initcall_##fn \
	__attribute_used__ __attribute__((__section__(".con_initcall.init")))=fn

#define security_initcall(fn) \
	static initcall_t __initcall_##fn \
	__attribute_used__ __attribute__((__section__(".security_initcall.init"))) = fn

struct obs_kernel_param {
	const char *str;
	int (*setup_func)(char *);
	int early;
};

/*
 * Only for really core code.  See moduleparam.h for the normal way.
 *
 * Force the alignment so the compiler doesn't space elements of the
 * obs_kernel_param "array" too far apart in .init.setup.
 */
#define __setup_param(str, unique_id, fn, early)			\
	static char __setup_str_##unique_id[] __initdata = str;	\
	static struct obs_kernel_param __setup_##unique_id	\
		__attribute_used__				\
		__attribute__((__section__(".init.setup")))	\
		__attribute__((aligned((sizeof(long)))))	\
		= { __setup_str_##unique_id, fn, early }

#define __setup_null_param(str, unique_id)			\
	__setup_param(str, unique_id, NULL, 0)

#define __setup(str, fn)					\
	__setup_param(str, fn, fn, 0)

#define __obsolete_setup(str)					\
	__setup_null_param(str, __LINE__)

/* NOTE: fn is as per module_param, not __setup!  Emits warning if fn
 * returns non-zero. */
#define early_param(str, fn)					\
	__setup_param(str, fn, fn, 1)

/* Relies on saved_command_line being set */
void __init parse_early_param(void);
#endif /* __ASSEMBLY__ */

/**
 * module_init() - driver initialization entry point
 * @x: function to be run at kernel boot time or module insertion
 * 
 * module_init() will either be called during do_initcalls() (if
 * builtin) or at module insertion time (if a module).  There can only
 * be one per module.
 */
#define module_init(x)	__initcall(x);

/**
 * module_exit() - driver exit entry point
 * @x: function to be run when driver is removed
 * 
 * module_exit() will wrap the driver clean-up code
 * with cleanup_module() when used with rmmod when
 * the driver is a module.  If the driver is statically
 * compiled into the kernel, module_exit() has no effect.
 * There can only be one per module.
 */
#define module_exit(x)	__exitcall(x);

#else /* MODULE */

/* Don't use these in modules, but some people do... */
#define core_initcall(fn)		module_init(fn)
#define postcore_initcall(fn)		module_init(fn)
#define arch_initcall(fn)		module_init(fn)
#define subsys_initcall(fn)		module_init(fn)
#define fs_initcall(fn)			module_init(fn)
#define device_initcall(fn)		module_init(fn)
#define late_initcall(fn)		module_init(fn)

#define security_initcall(fn)		module_init(fn)

/* These macros create a dummy inline: gcc 2.9x does not count alias
 as usage, hence the `unused function' warning when __init functions
 are declared static. We use the dummy __*_module_inline functions
 both to kill the warning and check the type of the init/cleanup
 function. */

/* Each module must use one module_init(), or one no_module_init */
#define module_init(initfn)					\
	static inline initcall_t __inittest(void)		\
	{ return initfn; }					\
	int init_module(void) __attribute__((alias(#initfn)));

/* This is only required if you want to be unloadable. */
#define module_exit(exitfn)					\
	static inline exitcall_t __exittest(void)		\
	{ return exitfn; }					\
	void cleanup_module(void) __attribute__((alias(#exitfn)));

#define __setup_param(str, unique_id, fn)	/* nothing */
#define __setup_null_param(str, unique_id) 	/* nothing */
#define __setup(str, func) 			/* nothing */
#define __obsolete_setup(str) 			/* nothing */
#endif

/* Data marked not to be saved by software_suspend() */
#define __nosavedata __attribute__ ((__section__ (".data.nosave")))

/* This means "can be init if no module support, otherwise module load
   may call it." */
#ifdef CONFIG_MODULES
#define __init_or_module
#define __initdata_or_module
#else
#define __init_or_module __init
#define __initdata_or_module __initdata
#endif /*CONFIG_MODULES*/

#ifdef CONFIG_HOTPLUG
#define __devinit
#define __devinitdata
#define __devexit
#define __devexitdata
#else
#define __devinit __init
#define __devinitdata __initdata
#define __devexit __exit
#define __devexitdata __exitdata
#endif

#ifdef CONFIG_HOTPLUG_CPU
#define __cpuinit
#define __cpuinitdata
#define __cpuexit
#define __cpuexitdata
#else
#define __cpuinit	__init
#define __cpuinitdata __initdata
#define __cpuexit __exit
#define __cpuexitdata	__exitdata
#endif

#if defined(CONFIG_MEMORY_HOTPLUG) || defined(CONFIG_ACPI_HOTPLUG_MEMORY) \
	|| defined(CONFIG_ACPI_HOTPLUG_MEMORY_MODULE)
#define __meminit
#define __meminitdata
#define __memexit
#define __memexitdata
#else
#define __meminit	__init
#define __meminitdata __initdata
#define __memexit __exit
#define __memexitdata	__exitdata
#endif

/* Functions marked as __devexit may be discarded at kernel link time, depending
   on config options.  Newer versions of binutils detect references from
   retained sections to discarded sections and flag an error.  Pointers to
   __devexit functions must use __devexit_p(function_name), the wrapper will
   insert either the function_name or NULL, depending on the config options.
 */
#if defined(MODULE) || defined(CONFIG_HOTPLUG)
#define __devexit_p(x) x
#else
#define __devexit_p(x) NULL
#endif

#ifdef MODULE
#define __exit_p(x) x
#else
#define __exit_p(x) NULL
#endif

#endif /* _LINUX_INIT_H */