Linux 4.6-rc6
[cris-mirror.git] / include / linux / init.h
blobaedb254abc37204a091b790eedfde857dc22155f
1 #ifndef _LINUX_INIT_H
2 #define _LINUX_INIT_H
4 #include <linux/compiler.h>
5 #include <linux/types.h>
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
13 * Usage:
14 * For functions:
16 * You should add __init immediately before the function name, like:
18 * static void __init initme(int x, int y)
19 * {
20 * extern int z; z = x * y;
21 * }
23 * If the function has a prototype somewhere, you can also add
24 * __init between closing brace of the prototype and semicolon:
26 * extern int initialize_foobar_device(int, int, int) __init;
28 * For initialized data:
29 * You should insert __initdata or __initconst between the variable name
30 * and equal sign followed by value, e.g.:
32 * static int init_variable __initdata = 0;
33 * static const char linux_logo[] __initconst = { 0x32, 0x36, ... };
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.
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)
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.
53 #ifdef CONFIG_BROKEN_RODATA
54 #define __constsection(x)
55 #else
56 #define __constsection(x) __section(x)
57 #endif
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.
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).
74 * The markers follow same syntax rules as __init / __initdata.
76 #define __ref __section(.ref.text) noinline
77 #define __refdata __section(.ref.data)
78 #define __refconst __constsection(.ref.rodata)
80 /* compatibility defines */
81 #define __init_refok __ref
82 #define __initdata_refok __refdata
83 #define __exit_refok __ref
86 #ifdef MODULE
87 #define __exitused
88 #else
89 #define __exitused __used
90 #endif
92 #define __exit __section(.exit.text) __exitused __cold notrace
94 /* Used for MEMORY_HOTPLUG */
95 #define __meminit __section(.meminit.text) __cold notrace
96 #define __meminitdata __section(.meminit.data)
97 #define __meminitconst __constsection(.meminit.rodata)
98 #define __memexit __section(.memexit.text) __exitused __cold notrace
99 #define __memexitdata __section(.memexit.data)
100 #define __memexitconst __constsection(.memexit.rodata)
102 /* For assembly routines */
103 #define __HEAD .section ".head.text","ax"
104 #define __INIT .section ".init.text","ax"
105 #define __FINIT .previous
107 #define __INITDATA .section ".init.data","aw",%progbits
108 #define __INITRODATA .section ".init.rodata","a",%progbits
109 #define __FINITDATA .previous
111 #define __MEMINIT .section ".meminit.text", "ax"
112 #define __MEMINITDATA .section ".meminit.data", "aw"
113 #define __MEMINITRODATA .section ".meminit.rodata", "a"
115 /* silence warnings when references are OK */
116 #define __REF .section ".ref.text", "ax"
117 #define __REFDATA .section ".ref.data", "aw"
118 #define __REFCONST .section ".ref.rodata", "a"
120 #ifndef __ASSEMBLY__
122 * Used for initialization calls..
124 typedef int (*initcall_t)(void);
125 typedef void (*exitcall_t)(void);
127 extern initcall_t __con_initcall_start[], __con_initcall_end[];
128 extern initcall_t __security_initcall_start[], __security_initcall_end[];
130 /* Used for contructor calls. */
131 typedef void (*ctor_fn_t)(void);
133 /* Defined in init/main.c */
134 extern int do_one_initcall(initcall_t fn);
135 extern char __initdata boot_command_line[];
136 extern char *saved_command_line;
137 extern unsigned int reset_devices;
139 /* used by init/main.c */
140 void setup_arch(char **);
141 void prepare_namespace(void);
142 void __init load_default_modules(void);
143 int __init init_rootfs(void);
145 #ifdef CONFIG_DEBUG_RODATA
146 void mark_rodata_ro(void);
147 #endif
149 extern void (*late_time_init)(void);
151 extern bool initcall_debug;
153 #endif
155 #ifndef MODULE
157 #ifndef __ASSEMBLY__
159 #ifdef CONFIG_LTO
160 /* Work around a LTO gcc problem: when there is no reference to a variable
161 * in a module it will be moved to the end of the program. This causes
162 * reordering of initcalls which the kernel does not like.
163 * Add a dummy reference function to avoid this. The function is
164 * deleted by the linker.
166 #define LTO_REFERENCE_INITCALL(x) \
167 ; /* yes this is needed */ \
168 static __used __exit void *reference_##x(void) \
170 return &x; \
172 #else
173 #define LTO_REFERENCE_INITCALL(x)
174 #endif
176 /* initcalls are now grouped by functionality into separate
177 * subsections. Ordering inside the subsections is determined
178 * by link order.
179 * For backwards compatibility, initcall() puts the call in
180 * the device init subsection.
182 * The `id' arg to __define_initcall() is needed so that multiple initcalls
183 * can point at the same handler without causing duplicate-symbol build errors.
186 #define __define_initcall(fn, id) \
187 static initcall_t __initcall_##fn##id __used \
188 __attribute__((__section__(".initcall" #id ".init"))) = fn; \
189 LTO_REFERENCE_INITCALL(__initcall_##fn##id)
192 * Early initcalls run before initializing SMP.
194 * Only for built-in code, not modules.
196 #define early_initcall(fn) __define_initcall(fn, early)
199 * A "pure" initcall has no dependencies on anything else, and purely
200 * initializes variables that couldn't be statically initialized.
202 * This only exists for built-in code, not for modules.
203 * Keep main.c:initcall_level_names[] in sync.
205 #define pure_initcall(fn) __define_initcall(fn, 0)
207 #define core_initcall(fn) __define_initcall(fn, 1)
208 #define core_initcall_sync(fn) __define_initcall(fn, 1s)
209 #define postcore_initcall(fn) __define_initcall(fn, 2)
210 #define postcore_initcall_sync(fn) __define_initcall(fn, 2s)
211 #define arch_initcall(fn) __define_initcall(fn, 3)
212 #define arch_initcall_sync(fn) __define_initcall(fn, 3s)
213 #define subsys_initcall(fn) __define_initcall(fn, 4)
214 #define subsys_initcall_sync(fn) __define_initcall(fn, 4s)
215 #define fs_initcall(fn) __define_initcall(fn, 5)
216 #define fs_initcall_sync(fn) __define_initcall(fn, 5s)
217 #define rootfs_initcall(fn) __define_initcall(fn, rootfs)
218 #define device_initcall(fn) __define_initcall(fn, 6)
219 #define device_initcall_sync(fn) __define_initcall(fn, 6s)
220 #define late_initcall(fn) __define_initcall(fn, 7)
221 #define late_initcall_sync(fn) __define_initcall(fn, 7s)
223 #define __initcall(fn) device_initcall(fn)
225 #define __exitcall(fn) \
226 static exitcall_t __exitcall_##fn __exit_call = fn
228 #define console_initcall(fn) \
229 static initcall_t __initcall_##fn \
230 __used __section(.con_initcall.init) = fn
232 #define security_initcall(fn) \
233 static initcall_t __initcall_##fn \
234 __used __section(.security_initcall.init) = fn
236 struct obs_kernel_param {
237 const char *str;
238 int (*setup_func)(char *);
239 int early;
243 * Only for really core code. See moduleparam.h for the normal way.
245 * Force the alignment so the compiler doesn't space elements of the
246 * obs_kernel_param "array" too far apart in .init.setup.
248 #define __setup_param(str, unique_id, fn, early) \
249 static const char __setup_str_##unique_id[] __initconst \
250 __aligned(1) = str; \
251 static struct obs_kernel_param __setup_##unique_id \
252 __used __section(.init.setup) \
253 __attribute__((aligned((sizeof(long))))) \
254 = { __setup_str_##unique_id, fn, early }
256 #define __setup(str, fn) \
257 __setup_param(str, fn, fn, 0)
260 * NOTE: fn is as per module_param, not __setup!
261 * Emits warning if fn returns non-zero.
263 #define early_param(str, fn) \
264 __setup_param(str, fn, fn, 1)
266 #define early_param_on_off(str_on, str_off, var, config) \
268 int var = IS_ENABLED(config); \
270 static int __init parse_##var##_on(char *arg) \
272 var = 1; \
273 return 0; \
275 __setup_param(str_on, parse_##var##_on, parse_##var##_on, 1); \
277 static int __init parse_##var##_off(char *arg) \
279 var = 0; \
280 return 0; \
282 __setup_param(str_off, parse_##var##_off, parse_##var##_off, 1)
284 /* Relies on boot_command_line being set */
285 void __init parse_early_param(void);
286 void __init parse_early_options(char *cmdline);
287 #endif /* __ASSEMBLY__ */
289 #else /* MODULE */
291 #define __setup_param(str, unique_id, fn) /* nothing */
292 #define __setup(str, func) /* nothing */
293 #endif
295 /* Data marked not to be saved by software suspend */
296 #define __nosavedata __section(.data..nosave)
298 #ifdef MODULE
299 #define __exit_p(x) x
300 #else
301 #define __exit_p(x) NULL
302 #endif
304 #endif /* _LINUX_INIT_H */