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 __latent_entropy
43 #define __initdata __section(.init.data)
44 #define __initconst __section(.init.rodata)
45 #define __exitdata __section(.exit.data)
46 #define __exit_call __used __section(.exitcall.exit)
47
48 /*
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 *
56 * The following markers are used for the cases where the reference to
57 * the *init / *exit section (code or data) is valid and will teach
58 * modpost not to issue a warning. Intended semantics is that a code or
59 * data tagged __ref* can reference code or data from init section without
60 * producing a warning (of course, no warning does not mean code is
61 * correct, so optimally document why the __ref is needed and why it's OK).
62 *
63 * The markers follow same syntax rules as __init / __initdata.
64 */
65 #define __ref __section(.ref.text) noinline
66 #define __refdata __section(.ref.data)
67 #define __refconst __section(.ref.rodata)
68
69 #ifdef MODULE
70 #define __exitused
71 #else
72 #define __exitused __used
73 #endif
74
75 #define __exit __section(.exit.text) __exitused __cold notrace
76
77 /* Used for MEMORY_HOTPLUG */
78 #define __meminit __section(.meminit.text) __cold notrace \
79 __latent_entropy
80 #define __meminitdata __section(.meminit.data)
81 #define __meminitconst __section(.meminit.rodata)
82 #define __memexit __section(.memexit.text) __exitused __cold notrace
83 #define __memexitdata __section(.memexit.data)
84 #define __memexitconst __section(.memexit.rodata)
85
86 /* For assembly routines */
87 #define __HEAD .section ".head.text","ax"
88 #define __INIT .section ".init.text","ax"
89 #define __FINIT .previous
90
91 #define __INITDATA .section ".init.data","aw",%progbits
92 #define __INITRODATA .section ".init.rodata","a",%progbits
93 #define __FINITDATA .previous
94
95 #define __MEMINIT .section ".meminit.text", "ax"
96 #define __MEMINITDATA .section ".meminit.data", "aw"
97 #define __MEMINITRODATA .section ".meminit.rodata", "a"
98
99 /* silence warnings when references are OK */
100 #define __REF .section ".ref.text", "ax"
101 #define __REFDATA .section ".ref.data", "aw"
102 #define __REFCONST .section ".ref.rodata", "a"
103
104 #ifndef __ASSEMBLY__
105 /*
106 * Used for initialization calls..
107 */
108 typedef int (*initcall_t)(void);
109 typedef void (*exitcall_t)(void);
110
111 extern initcall_t __con_initcall_start[], __con_initcall_end[];
112 extern initcall_t __security_initcall_start[], __security_initcall_end[];
113
114 /* Used for contructor calls. */
115 typedef void (*ctor_fn_t)(void);
116
117 /* Defined in init/main.c */
118 extern int do_one_initcall(initcall_t fn);
119 extern char __initdata boot_command_line[];
120 extern char *saved_command_line;
121 extern unsigned int reset_devices;
122
123 /* used by init/main.c */
124 void setup_arch(char **);
125 void prepare_namespace(void);
126 void __init load_default_modules(void);
127 int __init init_rootfs(void);
128
129 #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
130 extern bool rodata_enabled;
131 #endif
132 #ifdef CONFIG_STRICT_KERNEL_RWX
133 void mark_rodata_ro(void);
134 #endif
135
136 extern void (*late_time_init)(void);
137
138 extern bool initcall_debug;
139
140 #endif
141
142 #ifndef MODULE
143
144 #ifndef __ASSEMBLY__
145
146 /*
147 * initcalls are now grouped by functionality into separate
148 * subsections. Ordering inside the subsections is determined
149 * by link order.
150 * For backwards compatibility, initcall() puts the call in
151 * the device init subsection.
152 *
153 * The `id' arg to __define_initcall() is needed so that multiple initcalls
154 * can point at the same handler without causing duplicate-symbol build errors.
155 *
156 * Initcalls are run by placing pointers in initcall sections that the
157 * kernel iterates at runtime. The linker can do dead code / data elimination
158 * and remove that completely, so the initcall sections have to be marked
159 * as KEEP() in the linker script.
160 */
161
162 #define __define_initcall(fn, id) \
163 static initcall_t __initcall_##fn##id __used \
164 __attribute__((__section__(".initcall" #id ".init"))) = fn;
165
166 /*
167 * Early initcalls run before initializing SMP.
168 *
169 * Only for built-in code, not modules.
170 */
171 #define early_initcall(fn) __define_initcall(fn, early)
172
173 /*
174 * A "pure" initcall has no dependencies on anything else, and purely
175 * initializes variables that couldn't be statically initialized.
176 *
177 * This only exists for built-in code, not for modules.
178 * Keep main.c:initcall_level_names[] in sync.
179 */
180 #define pure_initcall(fn) __define_initcall(fn, 0)
181
182 #define core_initcall(fn) __define_initcall(fn, 1)
183 #define core_initcall_sync(fn) __define_initcall(fn, 1s)
184 #define postcore_initcall(fn) __define_initcall(fn, 2)
185 #define postcore_initcall_sync(fn) __define_initcall(fn, 2s)
186 #define arch_initcall(fn) __define_initcall(fn, 3)
187 #define arch_initcall_sync(fn) __define_initcall(fn, 3s)
188 #define subsys_initcall(fn) __define_initcall(fn, 4)
189 #define subsys_initcall_sync(fn) __define_initcall(fn, 4s)
190 #define fs_initcall(fn) __define_initcall(fn, 5)
191 #define fs_initcall_sync(fn) __define_initcall(fn, 5s)
192 #define rootfs_initcall(fn) __define_initcall(fn, rootfs)
193 #define device_initcall(fn) __define_initcall(fn, 6)
194 #define device_initcall_sync(fn) __define_initcall(fn, 6s)
195 #define late_initcall(fn) __define_initcall(fn, 7)
196 #define late_initcall_sync(fn) __define_initcall(fn, 7s)
197
198 #define __initcall(fn) device_initcall(fn)
199
200 #define __exitcall(fn) \
201 static exitcall_t __exitcall_##fn __exit_call = fn
202
203 #define console_initcall(fn) \
204 static initcall_t __initcall_##fn \
205 __used __section(.con_initcall.init) = fn
206
207 #define security_initcall(fn) \
208 static initcall_t __initcall_##fn \
209 __used __section(.security_initcall.init) = fn
210
211 struct obs_kernel_param {
212 const char *str;
213 int (*setup_func)(char *);
214 int early;
215 };
216
217 /*
218 * Only for really core code. See moduleparam.h for the normal way.
219 *
220 * Force the alignment so the compiler doesn't space elements of the
221 * obs_kernel_param "array" too far apart in .init.setup.
222 */
223 #define __setup_param(str, unique_id, fn, early) \
224 static const char __setup_str_##unique_id[] __initconst \
225 __aligned(1) = str; \
226 static struct obs_kernel_param __setup_##unique_id \
227 __used __section(.init.setup) \
228 __attribute__((aligned((sizeof(long))))) \
229 = { __setup_str_##unique_id, fn, early }
230
231 #define __setup(str, fn) \
232 __setup_param(str, fn, fn, 0)
233
234 /*
235 * NOTE: fn is as per module_param, not __setup!
236 * Emits warning if fn returns non-zero.
237 */
238 #define early_param(str, fn) \
239 __setup_param(str, fn, fn, 1)
240
241 #define early_param_on_off(str_on, str_off, var, config) \
242 \
243 int var = IS_ENABLED(config); \
244 \
245 static int __init parse_##var##_on(char *arg) \
246 { \
247 var = 1; \
248 return 0; \
249 } \
250 __setup_param(str_on, parse_##var##_on, parse_##var##_on, 1); \
251 \
252 static int __init parse_##var##_off(char *arg) \
253 { \
254 var = 0; \
255 return 0; \
256 } \
257 __setup_param(str_off, parse_##var##_off, parse_##var##_off, 1)
258
259 /* Relies on boot_command_line being set */
260 void __init parse_early_param(void);
261 void __init parse_early_options(char *cmdline);
262 #endif /* __ASSEMBLY__ */
263
264 #else /* MODULE */
265
266 #define __setup_param(str, unique_id, fn) /* nothing */
267 #define __setup(str, func) /* nothing */
268 #endif
269
270 /* Data marked not to be saved by software suspend */
271 #define __nosavedata __section(.data..nosave)
272
273 #ifdef MODULE
274 #define __exit_p(x) x
275 #else
276 #define __exit_p(x) NULL
277 #endif
278
279 #endif /* _LINUX_INIT_H */
280
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