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1 #ifndef _LINUX_INIT_H
2 #define _LINUX_INIT_H
3
4 #include <linux/compiler.h>
5 #include <linux/types.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 or __initconst between the variable name
30 * and equal sign followed by value, e.g.:
31 *
32 * static int init_variable __initdata = 0;
33 * static const char linux_logo[] __initconst = { 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
40 /* These are for everybody (although not all archs will actually
41 discard it in modules) */
42 #define __init __section(.init.text) __cold notrace
43 #define __initdata __section(.init.data)
44 #define __initconst __constsection(.init.rodata)
45 #define __exitdata __section(.exit.data)
46 #define __exit_call __used __section(.exitcall.exit)
47
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
59 /*
60 * modpost check for section mismatches during the kernel build.
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.
66 *
67 * The following markers are used for the cases where the reference to
68 * the *init / *exit section (code or data) is valid and will teach
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 */
76 #define __ref __section(.ref.text) noinline
77 #define __refdata __section(.ref.data)
78 #define __refconst __constsection(.ref.rodata)
79
80 /* compatibility defines */
81 #define __init_refok __ref
82 #define __initdata_refok __refdata
83 #define __exit_refok __ref
84
85
86 #ifdef MODULE
87 #define __exitused
88 #else
89 #define __exitused __used
90 #endif
91
92 #define __exit __section(.exit.text) __exitused __cold notrace
93
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
101
102 /* Used for MEMORY_HOTPLUG */
103 #define __meminit __section(.meminit.text) __cold notrace
104 #define __meminitdata __section(.meminit.data)
105 #define __meminitconst __constsection(.meminit.rodata)
106 #define __memexit __section(.memexit.text) __exitused __cold notrace
107 #define __memexitdata __section(.memexit.data)
108 #define __memexitconst __constsection(.memexit.rodata)
109
110 /* For assembly routines */
111 #define __HEAD .section ".head.text","ax"
112 #define __INIT .section ".init.text","ax"
113 #define __FINIT .previous
114
115 #define __INITDATA .section ".init.data","aw",%progbits
116 #define __INITRODATA .section ".init.rodata","a",%progbits
117 #define __FINITDATA .previous
118
119 /* temporary, until all users are removed */
120 #define __CPUINIT
121
122 #define __MEMINIT .section ".meminit.text", "ax"
123 #define __MEMINITDATA .section ".meminit.data", "aw"
124 #define __MEMINITRODATA .section ".meminit.rodata", "a"
125
126 /* silence warnings when references are OK */
127 #define __REF .section ".ref.text", "ax"
128 #define __REFDATA .section ".ref.data", "aw"
129 #define __REFCONST .section ".ref.rodata", "a"
130
131 #ifndef __ASSEMBLY__
132 /*
133 * Used for initialization calls..
134 */
135 typedef int (*initcall_t)(void);
136 typedef void (*exitcall_t)(void);
137
138 extern initcall_t __con_initcall_start[], __con_initcall_end[];
139 extern initcall_t __security_initcall_start[], __security_initcall_end[];
140
141 /* Used for contructor calls. */
142 typedef void (*ctor_fn_t)(void);
143
144 /* Defined in init/main.c */
145 extern int do_one_initcall(initcall_t fn);
146 extern char __initdata boot_command_line[];
147 extern char *saved_command_line;
148 extern unsigned int reset_devices;
149
150 /* used by init/main.c */
151 void setup_arch(char **);
152 void prepare_namespace(void);
153 void __init load_default_modules(void);
154 int __init init_rootfs(void);
155
156 extern void (*late_time_init)(void);
157
158 extern bool initcall_debug;
159
160 #endif
161
162 #ifndef MODULE
163
164 #ifndef __ASSEMBLY__
165
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
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.
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.
191 */
192
193 #define __define_initcall(fn, id) \
194 static initcall_t __initcall_##fn##id __used \
195 __attribute__((__section__(".initcall" #id ".init"))) = fn; \
196 LTO_REFERENCE_INITCALL(__initcall_##fn##id)
197
198 /*
199 * Early initcalls run before initializing SMP.
200 *
201 * Only for built-in code, not modules.
202 */
203 #define early_initcall(fn) __define_initcall(fn, early)
204
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.
210 * Keep main.c:initcall_level_names[] in sync.
211 */
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)
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 \
237 __used __section(.con_initcall.init) = fn
238
239 #define security_initcall(fn) \
240 static initcall_t __initcall_##fn \
241 __used __section(.security_initcall.init) = fn
242
243 struct 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) \
256 static const char __setup_str_##unique_id[] __initconst \
257 __aligned(1) = str; \
258 static struct obs_kernel_param __setup_##unique_id \
259 __used __section(.init.setup) \
260 __attribute__((aligned((sizeof(long))))) \
261 = { __setup_str_##unique_id, fn, early }
262
263 #define __setup(str, fn) \
264 __setup_param(str, fn, fn, 0)
265
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
271 /* Relies on boot_command_line being set */
272 void __init parse_early_param(void);
273 void __init parse_early_options(char *cmdline);
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 *
280 * module_init() will either be called during do_initcalls() (if
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
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 */
307 #define early_initcall(fn) module_init(fn)
308 #define core_initcall(fn) module_init(fn)
309 #define core_initcall_sync(fn) module_init(fn)
310 #define postcore_initcall(fn) module_init(fn)
311 #define postcore_initcall_sync(fn) module_init(fn)
312 #define arch_initcall(fn) module_init(fn)
313 #define subsys_initcall(fn) module_init(fn)
314 #define subsys_initcall_sync(fn) module_init(fn)
315 #define fs_initcall(fn) module_init(fn)
316 #define fs_initcall_sync(fn) module_init(fn)
317 #define rootfs_initcall(fn) module_init(fn)
318 #define device_initcall(fn) module_init(fn)
319 #define device_initcall_sync(fn) module_init(fn)
320 #define late_initcall(fn) module_init(fn)
321 #define late_initcall_sync(fn) module_init(fn)
322
323 #define console_initcall(fn) module_init(fn)
324 #define security_initcall(fn) module_init(fn)
325
326 /* Each module must use one module_init(). */
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 */
339 #define __setup(str, func) /* nothing */
340 #endif
341
342 /* Data marked not to be saved by software suspend */
343 #define __nosavedata __section(.data..nosave)
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
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
354 #else
355 #define __init_or_module __init
356 #define __initdata_or_module __initdata
357 #define __initconst_or_module __initconst
358 #define __INIT_OR_MODULE __INIT
359 #define __INITDATA_OR_MODULE __INITDATA
360 #define __INITRODATA_OR_MODULE __INITRODATA
361 #endif /*CONFIG_MODULES*/
362
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 */