Merge branch 'timers-for-linus-migration' of git://git.kernel.org/pub/scm/linux/kerne...
[deliverable/linux.git] / include / linux / init.h
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1da177e4
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1#ifndef _LINUX_INIT_H
2#define _LINUX_INIT_H
3
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4#include <linux/compiler.h>
5
6/* These macros are used to mark some functions or
7 * initialized data (doesn't apply to uninitialized data)
8 * as `initialization' functions. The kernel can take this
9 * as hint that the function is used only during the initialization
10 * phase and free up used memory resources after
11 *
12 * Usage:
13 * For functions:
14 *
15 * You should add __init immediately before the function name, like:
16 *
17 * static void __init initme(int x, int y)
18 * {
19 * extern int z; z = x * y;
20 * }
21 *
22 * If the function has a prototype somewhere, you can also add
23 * __init between closing brace of the prototype and semicolon:
24 *
25 * extern int initialize_foobar_device(int, int, int) __init;
26 *
27 * For initialized data:
28 * You should insert __initdata between the variable name and equal
29 * sign followed by value, e.g.:
30 *
31 * static int init_variable __initdata = 0;
32 * static char linux_logo[] __initdata = { 0x32, 0x36, ... };
33 *
34 * Don't forget to initialize data not at file scope, i.e. within a function,
35 * as gcc otherwise puts the data into the bss section and not into the init
36 * section.
37 *
38 * Also note, that this data cannot be "const".
39 */
40
41/* These are for everybody (although not all archs will actually
42 discard it in modules) */
fed1939c 43#define __init __section(.init.text) __cold notrace
f3fe866d 44#define __initdata __section(.init.data)
37c514e3 45#define __initconst __section(.init.rodata)
f3fe866d 46#define __exitdata __section(.exit.data)
3ff6eecc 47#define __exit_call __used __section(.exitcall.exit)
1da177e4 48
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49/* modpost check for section mismatches during the kernel build.
50 * A section mismatch happens when there are references from a
51 * code or data section to an init section (both code or data).
52 * The init sections are (for most archs) discarded by the kernel
53 * when early init has completed so all such references are potential bugs.
54 * For exit sections the same issue exists.
55 * The following markers are used for the cases where the reference to
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56 * the *init / *exit section (code or data) is valid and will teach
57 * modpost not to issue a warning.
0e0d314e 58 * The markers follow same syntax rules as __init / __initdata. */
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59#define __ref __section(.ref.text) noinline
60#define __refdata __section(.ref.data)
61#define __refconst __section(.ref.rodata)
62
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63/* compatibility defines */
64#define __init_refok __ref
65#define __initdata_refok __refdata
66#define __exit_refok __ref
67
0e0d314e 68
1da177e4 69#ifdef MODULE
eb8f6890 70#define __exitused
1da177e4 71#else
eb8f6890 72#define __exitused __used
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73#endif
74
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75#define __exit __section(.exit.text) __exitused __cold
76
77/* Used for HOTPLUG */
78#define __devinit __section(.devinit.text) __cold
79#define __devinitdata __section(.devinit.data)
80#define __devinitconst __section(.devinit.rodata)
81#define __devexit __section(.devexit.text) __exitused __cold
82#define __devexitdata __section(.devexit.data)
83#define __devexitconst __section(.devexit.rodata)
84
85/* Used for HOTPLUG_CPU */
86#define __cpuinit __section(.cpuinit.text) __cold
87#define __cpuinitdata __section(.cpuinit.data)
88#define __cpuinitconst __section(.cpuinit.rodata)
89#define __cpuexit __section(.cpuexit.text) __exitused __cold
90#define __cpuexitdata __section(.cpuexit.data)
91#define __cpuexitconst __section(.cpuexit.rodata)
92
93/* Used for MEMORY_HOTPLUG */
94#define __meminit __section(.meminit.text) __cold
95#define __meminitdata __section(.meminit.data)
96#define __meminitconst __section(.meminit.rodata)
97#define __memexit __section(.memexit.text) __exitused __cold
98#define __memexitdata __section(.memexit.data)
99#define __memexitconst __section(.memexit.rodata)
100
1da177e4 101/* For assembly routines */
7923f90f 102#define __HEAD .section ".head.text","ax"
1da177e4 103#define __INIT .section ".init.text","ax"
86c0baf1 104#define __FINIT .previous
eb8f6890 105
838c4118 106#define __INITDATA .section ".init.data","aw"
3f5e26ce 107#define __INITRODATA .section ".init.rodata","a"
9f9975a5 108#define __FINITDATA .previous
1da177e4 109
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110#define __DEVINIT .section ".devinit.text", "ax"
111#define __DEVINITDATA .section ".devinit.data", "aw"
3f5e26ce 112#define __DEVINITRODATA .section ".devinit.rodata", "a"
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113
114#define __CPUINIT .section ".cpuinit.text", "ax"
115#define __CPUINITDATA .section ".cpuinit.data", "aw"
3f5e26ce 116#define __CPUINITRODATA .section ".cpuinit.rodata", "a"
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117
118#define __MEMINIT .section ".meminit.text", "ax"
119#define __MEMINITDATA .section ".meminit.data", "aw"
3f5e26ce 120#define __MEMINITRODATA .section ".meminit.rodata", "a"
eb8f6890 121
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122/* silence warnings when references are OK */
123#define __REF .section ".ref.text", "ax"
124#define __REFDATA .section ".ref.data", "aw"
3f5e26ce 125#define __REFCONST .section ".ref.rodata", "a"
312b1485 126
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127#ifndef __ASSEMBLY__
128/*
129 * Used for initialization calls..
130 */
131typedef int (*initcall_t)(void);
132typedef void (*exitcall_t)(void);
133
134extern initcall_t __con_initcall_start[], __con_initcall_end[];
135extern initcall_t __security_initcall_start[], __security_initcall_end[];
136
137/* Defined in init/main.c */
59f9415f 138extern int do_one_initcall(initcall_t fn);
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139extern char __initdata boot_command_line[];
140extern char *saved_command_line;
7e96287d 141extern unsigned int reset_devices;
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142
143/* used by init/main.c */
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144void setup_arch(char **);
145void prepare_namespace(void);
77d47582 146
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147extern void (*late_time_init)(void);
148
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149#endif
150
151#ifndef MODULE
152
153#ifndef __ASSEMBLY__
154
155/* initcalls are now grouped by functionality into separate
156 * subsections. Ordering inside the subsections is determined
157 * by link order.
158 * For backwards compatibility, initcall() puts the call in
159 * the device init subsection.
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160 *
161 * The `id' arg to __define_initcall() is needed so that multiple initcalls
162 * can point at the same handler without causing duplicate-symbol build errors.
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163 */
164
735a7ffb 165#define __define_initcall(level,fn,id) \
3ff6eecc 166 static initcall_t __initcall_##fn##id __used \
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167 __attribute__((__section__(".initcall" level ".init"))) = fn
168
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169/*
170 * Early initcalls run before initializing SMP.
171 *
172 * Only for built-in code, not modules.
173 */
174#define early_initcall(fn) __define_initcall("early",fn,early)
175
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176/*
177 * A "pure" initcall has no dependencies on anything else, and purely
178 * initializes variables that couldn't be statically initialized.
179 *
180 * This only exists for built-in code, not for modules.
181 */
73dd1166 182#define pure_initcall(fn) __define_initcall("0",fn,0)
b3438f82 183
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184#define core_initcall(fn) __define_initcall("1",fn,1)
185#define core_initcall_sync(fn) __define_initcall("1s",fn,1s)
186#define postcore_initcall(fn) __define_initcall("2",fn,2)
187#define postcore_initcall_sync(fn) __define_initcall("2s",fn,2s)
188#define arch_initcall(fn) __define_initcall("3",fn,3)
189#define arch_initcall_sync(fn) __define_initcall("3s",fn,3s)
190#define subsys_initcall(fn) __define_initcall("4",fn,4)
191#define subsys_initcall_sync(fn) __define_initcall("4s",fn,4s)
192#define fs_initcall(fn) __define_initcall("5",fn,5)
193#define fs_initcall_sync(fn) __define_initcall("5s",fn,5s)
8d610dd5 194#define rootfs_initcall(fn) __define_initcall("rootfs",fn,rootfs)
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195#define device_initcall(fn) __define_initcall("6",fn,6)
196#define device_initcall_sync(fn) __define_initcall("6s",fn,6s)
197#define late_initcall(fn) __define_initcall("7",fn,7)
198#define late_initcall_sync(fn) __define_initcall("7s",fn,7s)
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199
200#define __initcall(fn) device_initcall(fn)
201
202#define __exitcall(fn) \
203 static exitcall_t __exitcall_##fn __exit_call = fn
204
205#define console_initcall(fn) \
206 static initcall_t __initcall_##fn \
3ff6eecc 207 __used __section(.con_initcall.init) = fn
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208
209#define security_initcall(fn) \
210 static initcall_t __initcall_##fn \
3ff6eecc 211 __used __section(.security_initcall.init) = fn
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212
213struct obs_kernel_param {
214 const char *str;
215 int (*setup_func)(char *);
216 int early;
217};
218
219/*
220 * Only for really core code. See moduleparam.h for the normal way.
221 *
222 * Force the alignment so the compiler doesn't space elements of the
223 * obs_kernel_param "array" too far apart in .init.setup.
224 */
225#define __setup_param(str, unique_id, fn, early) \
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226 static const char __setup_str_##unique_id[] __initconst \
227 __aligned(1) = str; \
1da177e4 228 static struct obs_kernel_param __setup_##unique_id \
3ff6eecc 229 __used __section(.init.setup) \
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230 __attribute__((aligned((sizeof(long))))) \
231 = { __setup_str_##unique_id, fn, early }
232
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233#define __setup(str, fn) \
234 __setup_param(str, fn, fn, 0)
235
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236/* NOTE: fn is as per module_param, not __setup! Emits warning if fn
237 * returns non-zero. */
238#define early_param(str, fn) \
239 __setup_param(str, fn, fn, 1)
240
30d7e0d4 241/* Relies on boot_command_line being set */
1da177e4 242void __init parse_early_param(void);
13977091 243void __init parse_early_options(char *cmdline);
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244#endif /* __ASSEMBLY__ */
245
246/**
247 * module_init() - driver initialization entry point
248 * @x: function to be run at kernel boot time or module insertion
249 *
72fd4a35 250 * module_init() will either be called during do_initcalls() (if
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251 * builtin) or at module insertion time (if a module). There can only
252 * be one per module.
253 */
254#define module_init(x) __initcall(x);
255
256/**
257 * module_exit() - driver exit entry point
258 * @x: function to be run when driver is removed
259 *
260 * module_exit() will wrap the driver clean-up code
261 * with cleanup_module() when used with rmmod when
262 * the driver is a module. If the driver is statically
263 * compiled into the kernel, module_exit() has no effect.
264 * There can only be one per module.
265 */
266#define module_exit(x) __exitcall(x);
267
268#else /* MODULE */
269
270/* Don't use these in modules, but some people do... */
271#define core_initcall(fn) module_init(fn)
272#define postcore_initcall(fn) module_init(fn)
273#define arch_initcall(fn) module_init(fn)
274#define subsys_initcall(fn) module_init(fn)
275#define fs_initcall(fn) module_init(fn)
276#define device_initcall(fn) module_init(fn)
277#define late_initcall(fn) module_init(fn)
278
279#define security_initcall(fn) module_init(fn)
280
4500d067 281/* Each module must use one module_init(). */
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282#define module_init(initfn) \
283 static inline initcall_t __inittest(void) \
284 { return initfn; } \
285 int init_module(void) __attribute__((alias(#initfn)));
286
287/* This is only required if you want to be unloadable. */
288#define module_exit(exitfn) \
289 static inline exitcall_t __exittest(void) \
290 { return exitfn; } \
291 void cleanup_module(void) __attribute__((alias(#exitfn)));
292
293#define __setup_param(str, unique_id, fn) /* nothing */
1da177e4 294#define __setup(str, func) /* nothing */
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295#endif
296
ab3bfca7 297/* Data marked not to be saved by software suspend */
f3fe866d 298#define __nosavedata __section(.data.nosave)
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299
300/* This means "can be init if no module support, otherwise module load
301 may call it." */
302#ifdef CONFIG_MODULES
303#define __init_or_module
304#define __initdata_or_module
305#else
306#define __init_or_module __init
307#define __initdata_or_module __initdata
308#endif /*CONFIG_MODULES*/
309
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310/* Functions marked as __devexit may be discarded at kernel link time, depending
311 on config options. Newer versions of binutils detect references from
312 retained sections to discarded sections and flag an error. Pointers to
313 __devexit functions must use __devexit_p(function_name), the wrapper will
314 insert either the function_name or NULL, depending on the config options.
315 */
316#if defined(MODULE) || defined(CONFIG_HOTPLUG)
317#define __devexit_p(x) x
318#else
319#define __devexit_p(x) NULL
320#endif
321
322#ifdef MODULE
323#define __exit_p(x) x
324#else
325#define __exit_p(x) NULL
326#endif
327
328#endif /* _LINUX_INIT_H */
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