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1da177e4
LT
1#ifndef _LINUX_INIT_H
2#define _LINUX_INIT_H
3
1da177e4 4#include <linux/compiler.h>
2329abfa 5#include <linux/types.h>
1da177e4
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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:
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GU
29 * You should insert __initdata or __initconst between the variable name
30 * and equal sign followed by value, e.g.:
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31 *
32 * static int init_variable __initdata = 0;
ae52bb23 33 * static const char linux_logo[] __initconst = { 0x32, 0x36, ... };
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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.
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38 */
39
40/* These are for everybody (although not all archs will actually
41 discard it in modules) */
fed1939c 42#define __init __section(.init.text) __cold notrace
f3fe866d 43#define __initdata __section(.init.data)
754b7b63 44#define __initconst __constsection(.init.rodata)
f3fe866d 45#define __exitdata __section(.exit.data)
3ff6eecc 46#define __exit_call __used __section(.exitcall.exit)
1da177e4 47
754b7b63
AK
48/*
49 * Some architecture have tool chains which do not handle rodata attributes
50 * correctly. For those disable special sections for const, so that other
51 * architectures can annotate correctly.
52 */
53#ifdef CONFIG_BROKEN_RODATA
54#define __constsection(x)
55#else
56#define __constsection(x) __section(x)
57#endif
58
5ea08178
MN
59/*
60 * modpost check for section mismatches during the kernel build.
0e0d314e
SR
61 * A section mismatch happens when there are references from a
62 * code or data section to an init section (both code or data).
63 * The init sections are (for most archs) discarded by the kernel
64 * when early init has completed so all such references are potential bugs.
65 * For exit sections the same issue exists.
5ea08178 66 *
0e0d314e 67 * The following markers are used for the cases where the reference to
312b1485 68 * the *init / *exit section (code or data) is valid and will teach
5ea08178
MN
69 * modpost not to issue a warning. Intended semantics is that a code or
70 * data tagged __ref* can reference code or data from init section without
71 * producing a warning (of course, no warning does not mean code is
72 * correct, so optimally document why the __ref is needed and why it's OK).
73 *
74 * The markers follow same syntax rules as __init / __initdata.
75 */
312b1485
SR
76#define __ref __section(.ref.text) noinline
77#define __refdata __section(.ref.data)
754b7b63 78#define __refconst __constsection(.ref.rodata)
312b1485 79
312b1485
SR
80/* compatibility defines */
81#define __init_refok __ref
82#define __initdata_refok __refdata
83#define __exit_refok __ref
84
0e0d314e 85
1da177e4 86#ifdef MODULE
eb8f6890 87#define __exitused
1da177e4 88#else
eb8f6890 89#define __exitused __used
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90#endif
91
f0201738 92#define __exit __section(.exit.text) __exitused __cold notrace
eb8f6890 93
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PG
94/* temporary, until all users are removed */
95#define __cpuinit
96#define __cpuinitdata
97#define __cpuinitconst
98#define __cpuexit
99#define __cpuexitdata
100#define __cpuexitconst
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101
102/* Used for MEMORY_HOTPLUG */
f0201738 103#define __meminit __section(.meminit.text) __cold notrace
eb8f6890 104#define __meminitdata __section(.meminit.data)
754b7b63 105#define __meminitconst __constsection(.meminit.rodata)
f0201738 106#define __memexit __section(.memexit.text) __exitused __cold notrace
eb8f6890 107#define __memexitdata __section(.memexit.data)
754b7b63 108#define __memexitconst __constsection(.memexit.rodata)
eb8f6890 109
1da177e4 110/* For assembly routines */
7923f90f 111#define __HEAD .section ".head.text","ax"
1da177e4 112#define __INIT .section ".init.text","ax"
86c0baf1 113#define __FINIT .previous
eb8f6890 114
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115#define __INITDATA .section ".init.data","aw",%progbits
116#define __INITRODATA .section ".init.rodata","a",%progbits
9f9975a5 117#define __FINITDATA .previous
1da177e4 118
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119/* temporary, until all users are removed */
120#define __CPUINIT
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121
122#define __MEMINIT .section ".meminit.text", "ax"
123#define __MEMINITDATA .section ".meminit.data", "aw"
3f5e26ce 124#define __MEMINITRODATA .section ".meminit.rodata", "a"
eb8f6890 125
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SR
126/* silence warnings when references are OK */
127#define __REF .section ".ref.text", "ax"
128#define __REFDATA .section ".ref.data", "aw"
3f5e26ce 129#define __REFCONST .section ".ref.rodata", "a"
312b1485 130
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131#ifndef __ASSEMBLY__
132/*
133 * Used for initialization calls..
134 */
135typedef int (*initcall_t)(void);
136typedef void (*exitcall_t)(void);
137
138extern initcall_t __con_initcall_start[], __con_initcall_end[];
139extern initcall_t __security_initcall_start[], __security_initcall_end[];
140
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PO
141/* Used for contructor calls. */
142typedef void (*ctor_fn_t)(void);
143
1da177e4 144/* Defined in init/main.c */
59f9415f 145extern int do_one_initcall(initcall_t fn);
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ABL
146extern char __initdata boot_command_line[];
147extern char *saved_command_line;
7e96287d 148extern unsigned int reset_devices;
77d47582
AB
149
150/* used by init/main.c */
46595390
AB
151void setup_arch(char **);
152void prepare_namespace(void);
bb813f4c 153void __init load_default_modules(void);
57f150a5 154int __init init_rootfs(void);
77d47582 155
7d195a54
AB
156extern void (*late_time_init)(void);
157
2329abfa 158extern bool initcall_debug;
f2511774 159
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160#endif
161
162#ifndef MODULE
163
164#ifndef __ASSEMBLY__
165
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166#ifdef CONFIG_LTO
167/* Work around a LTO gcc problem: when there is no reference to a variable
168 * in a module it will be moved to the end of the program. This causes
169 * reordering of initcalls which the kernel does not like.
170 * Add a dummy reference function to avoid this. The function is
171 * deleted by the linker.
172 */
173#define LTO_REFERENCE_INITCALL(x) \
174 ; /* yes this is needed */ \
175 static __used __exit void *reference_##x(void) \
176 { \
177 return &x; \
178 }
179#else
180#define LTO_REFERENCE_INITCALL(x)
181#endif
182
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183/* initcalls are now grouped by functionality into separate
184 * subsections. Ordering inside the subsections is determined
185 * by link order.
186 * For backwards compatibility, initcall() puts the call in
187 * the device init subsection.
735a7ffb
AM
188 *
189 * The `id' arg to __define_initcall() is needed so that multiple initcalls
190 * can point at the same handler without causing duplicate-symbol build errors.
1da177e4
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191 */
192
7929d407 193#define __define_initcall(fn, id) \
3ff6eecc 194 static initcall_t __initcall_##fn##id __used \
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AK
195 __attribute__((__section__(".initcall" #id ".init"))) = fn; \
196 LTO_REFERENCE_INITCALL(__initcall_##fn##id)
1da177e4 197
c2147a50
EGM
198/*
199 * Early initcalls run before initializing SMP.
200 *
201 * Only for built-in code, not modules.
202 */
7929d407 203#define early_initcall(fn) __define_initcall(fn, early)
c2147a50 204
b3438f82
LT
205/*
206 * A "pure" initcall has no dependencies on anything else, and purely
207 * initializes variables that couldn't be statically initialized.
208 *
209 * This only exists for built-in code, not for modules.
96263d28 210 * Keep main.c:initcall_level_names[] in sync.
b3438f82 211 */
7929d407
ML
212#define pure_initcall(fn) __define_initcall(fn, 0)
213
214#define core_initcall(fn) __define_initcall(fn, 1)
215#define core_initcall_sync(fn) __define_initcall(fn, 1s)
216#define postcore_initcall(fn) __define_initcall(fn, 2)
217#define postcore_initcall_sync(fn) __define_initcall(fn, 2s)
218#define arch_initcall(fn) __define_initcall(fn, 3)
219#define arch_initcall_sync(fn) __define_initcall(fn, 3s)
220#define subsys_initcall(fn) __define_initcall(fn, 4)
221#define subsys_initcall_sync(fn) __define_initcall(fn, 4s)
222#define fs_initcall(fn) __define_initcall(fn, 5)
223#define fs_initcall_sync(fn) __define_initcall(fn, 5s)
224#define rootfs_initcall(fn) __define_initcall(fn, rootfs)
225#define device_initcall(fn) __define_initcall(fn, 6)
226#define device_initcall_sync(fn) __define_initcall(fn, 6s)
227#define late_initcall(fn) __define_initcall(fn, 7)
228#define late_initcall_sync(fn) __define_initcall(fn, 7s)
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229
230#define __initcall(fn) device_initcall(fn)
231
232#define __exitcall(fn) \
233 static exitcall_t __exitcall_##fn __exit_call = fn
234
235#define console_initcall(fn) \
236 static initcall_t __initcall_##fn \
3ff6eecc 237 __used __section(.con_initcall.init) = fn
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238
239#define security_initcall(fn) \
240 static initcall_t __initcall_##fn \
3ff6eecc 241 __used __section(.security_initcall.init) = fn
1da177e4
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242
243struct obs_kernel_param {
244 const char *str;
245 int (*setup_func)(char *);
246 int early;
247};
248
249/*
250 * Only for really core code. See moduleparam.h for the normal way.
251 *
252 * Force the alignment so the compiler doesn't space elements of the
253 * obs_kernel_param "array" too far apart in .init.setup.
254 */
255#define __setup_param(str, unique_id, fn, early) \
fd6c3a8d
JB
256 static const char __setup_str_##unique_id[] __initconst \
257 __aligned(1) = str; \
1da177e4 258 static struct obs_kernel_param __setup_##unique_id \
3ff6eecc 259 __used __section(.init.setup) \
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260 __attribute__((aligned((sizeof(long))))) \
261 = { __setup_str_##unique_id, fn, early }
262
1da177e4
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263#define __setup(str, fn) \
264 __setup_param(str, fn, fn, 0)
265
1da177e4
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266/* NOTE: fn is as per module_param, not __setup! Emits warning if fn
267 * returns non-zero. */
268#define early_param(str, fn) \
269 __setup_param(str, fn, fn, 1)
270
30d7e0d4 271/* Relies on boot_command_line being set */
1da177e4 272void __init parse_early_param(void);
13977091 273void __init parse_early_options(char *cmdline);
1da177e4
LT
274#endif /* __ASSEMBLY__ */
275
276/**
277 * module_init() - driver initialization entry point
278 * @x: function to be run at kernel boot time or module insertion
279 *
72fd4a35 280 * module_init() will either be called during do_initcalls() (if
1da177e4
LT
281 * builtin) or at module insertion time (if a module). There can only
282 * be one per module.
283 */
284#define module_init(x) __initcall(x);
285
286/**
287 * module_exit() - driver exit entry point
288 * @x: function to be run when driver is removed
289 *
290 * module_exit() will wrap the driver clean-up code
291 * with cleanup_module() when used with rmmod when
292 * the driver is a module. If the driver is statically
293 * compiled into the kernel, module_exit() has no effect.
294 * There can only be one per module.
295 */
296#define module_exit(x) __exitcall(x);
297
298#else /* MODULE */
299
451ef1ca
TL
300/*
301 * In most cases loadable modules do not need custom
302 * initcall levels. There are still some valid cases where
303 * a driver may be needed early if built in, and does not
304 * matter when built as a loadable module. Like bus
305 * snooping debug drivers.
306 */
329bd411 307#define early_initcall(fn) module_init(fn)
1da177e4 308#define core_initcall(fn) module_init(fn)
451ef1ca 309#define core_initcall_sync(fn) module_init(fn)
1da177e4 310#define postcore_initcall(fn) module_init(fn)
451ef1ca 311#define postcore_initcall_sync(fn) module_init(fn)
1da177e4
LT
312#define arch_initcall(fn) module_init(fn)
313#define subsys_initcall(fn) module_init(fn)
451ef1ca 314#define subsys_initcall_sync(fn) module_init(fn)
1da177e4 315#define fs_initcall(fn) module_init(fn)
451ef1ca 316#define fs_initcall_sync(fn) module_init(fn)
b46d0c46 317#define rootfs_initcall(fn) module_init(fn)
1da177e4 318#define device_initcall(fn) module_init(fn)
451ef1ca 319#define device_initcall_sync(fn) module_init(fn)
1da177e4 320#define late_initcall(fn) module_init(fn)
451ef1ca 321#define late_initcall_sync(fn) module_init(fn)
1da177e4 322
b46d0c46 323#define console_initcall(fn) module_init(fn)
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324#define security_initcall(fn) module_init(fn)
325
4500d067 326/* Each module must use one module_init(). */
1da177e4
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327#define module_init(initfn) \
328 static inline initcall_t __inittest(void) \
329 { return initfn; } \
330 int init_module(void) __attribute__((alias(#initfn)));
331
332/* This is only required if you want to be unloadable. */
333#define module_exit(exitfn) \
334 static inline exitcall_t __exittest(void) \
335 { return exitfn; } \
336 void cleanup_module(void) __attribute__((alias(#exitfn)));
337
338#define __setup_param(str, unique_id, fn) /* nothing */
1da177e4 339#define __setup(str, func) /* nothing */
1da177e4
LT
340#endif
341
ab3bfca7 342/* Data marked not to be saved by software suspend */
07b3bb1e 343#define __nosavedata __section(.data..nosave)
1da177e4
LT
344
345/* This means "can be init if no module support, otherwise module load
346 may call it." */
347#ifdef CONFIG_MODULES
348#define __init_or_module
349#define __initdata_or_module
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JB
350#define __initconst_or_module
351#define __INIT_OR_MODULE .text
352#define __INITDATA_OR_MODULE .data
353#define __INITRODATA_OR_MODULE .section ".rodata","a",%progbits
1da177e4
LT
354#else
355#define __init_or_module __init
356#define __initdata_or_module __initdata
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JB
357#define __initconst_or_module __initconst
358#define __INIT_OR_MODULE __INIT
359#define __INITDATA_OR_MODULE __INITDATA
360#define __INITRODATA_OR_MODULE __INITRODATA
1da177e4
LT
361#endif /*CONFIG_MODULES*/
362
1da177e4
LT
363#ifdef MODULE
364#define __exit_p(x) x
365#else
366#define __exit_p(x) NULL
367#endif
368
369#endif /* _LINUX_INIT_H */