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1 : /* SPDX-License-Identifier: GPL-2.0 */
2 : #ifndef _LINUX_INIT_H
3 : #define _LINUX_INIT_H
4 :
5 : #include <linux/compiler.h>
6 : #include <linux/types.h>
7 :
8 : /* Built-in __init functions needn't be compiled with retpoline */
9 : #if defined(__noretpoline) && !defined(MODULE)
10 : #define __noinitretpoline __noretpoline
11 : #else
12 : #define __noinitretpoline
13 : #endif
14 :
15 : /* These macros are used to mark some functions or
16 : * initialized data (doesn't apply to uninitialized data)
17 : * as `initialization' functions. The kernel can take this
18 : * as hint that the function is used only during the initialization
19 : * phase and free up used memory resources after
20 : *
21 : * Usage:
22 : * For functions:
23 : *
24 : * You should add __init immediately before the function name, like:
25 : *
26 : * static void __init initme(int x, int y)
27 : * {
28 : * extern int z; z = x * y;
29 : * }
30 : *
31 : * If the function has a prototype somewhere, you can also add
32 : * __init between closing brace of the prototype and semicolon:
33 : *
34 : * extern int initialize_foobar_device(int, int, int) __init;
35 : *
36 : * For initialized data:
37 : * You should insert __initdata or __initconst between the variable name
38 : * and equal sign followed by value, e.g.:
39 : *
40 : * static int init_variable __initdata = 0;
41 : * static const char linux_logo[] __initconst = { 0x32, 0x36, ... };
42 : *
43 : * Don't forget to initialize data not at file scope, i.e. within a function,
44 : * as gcc otherwise puts the data into the bss section and not into the init
45 : * section.
46 : */
47 :
48 : /* These are for everybody (although not all archs will actually
49 : discard it in modules) */
50 : #define __init __section(".init.text") __cold __latent_entropy __noinitretpoline
51 : #define __initdata __section(".init.data")
52 : #define __initconst __section(".init.rodata")
53 : #define __exitdata __section(".exit.data")
54 : #define __exit_call __used __section(".exitcall.exit")
55 :
56 : /*
57 : * modpost check for section mismatches during the kernel build.
58 : * A section mismatch happens when there are references from a
59 : * code or data section to an init section (both code or data).
60 : * The init sections are (for most archs) discarded by the kernel
61 : * when early init has completed so all such references are potential bugs.
62 : * For exit sections the same issue exists.
63 : *
64 : * The following markers are used for the cases where the reference to
65 : * the *init / *exit section (code or data) is valid and will teach
66 : * modpost not to issue a warning. Intended semantics is that a code or
67 : * data tagged __ref* can reference code or data from init section without
68 : * producing a warning (of course, no warning does not mean code is
69 : * correct, so optimally document why the __ref is needed and why it's OK).
70 : *
71 : * The markers follow same syntax rules as __init / __initdata.
72 : */
73 : #define __ref __section(".ref.text") noinline
74 : #define __refdata __section(".ref.data")
75 : #define __refconst __section(".ref.rodata")
76 :
77 : #ifdef MODULE
78 : #define __exitused
79 : #else
80 : #define __exitused __used
81 : #endif
82 :
83 : #define __exit __section(".exit.text") __exitused __cold notrace
84 :
85 : /* Used for MEMORY_HOTPLUG */
86 : #define __meminit __section(".meminit.text") __cold notrace \
87 : __latent_entropy
88 : #define __meminitdata __section(".meminit.data")
89 : #define __meminitconst __section(".meminit.rodata")
90 : #define __memexit __section(".memexit.text") __exitused __cold notrace
91 : #define __memexitdata __section(".memexit.data")
92 : #define __memexitconst __section(".memexit.rodata")
93 :
94 : /* For assembly routines */
95 : #define __HEAD .section ".head.text","ax"
96 : #define __INIT .section ".init.text","ax"
97 : #define __FINIT .previous
98 :
99 : #define __INITDATA .section ".init.data","aw",%progbits
100 : #define __INITRODATA .section ".init.rodata","a",%progbits
101 : #define __FINITDATA .previous
102 :
103 : #define __MEMINIT .section ".meminit.text", "ax"
104 : #define __MEMINITDATA .section ".meminit.data", "aw"
105 : #define __MEMINITRODATA .section ".meminit.rodata", "a"
106 :
107 : /* silence warnings when references are OK */
108 : #define __REF .section ".ref.text", "ax"
109 : #define __REFDATA .section ".ref.data", "aw"
110 : #define __REFCONST .section ".ref.rodata", "a"
111 :
112 : #ifndef __ASSEMBLY__
113 : /*
114 : * Used for initialization calls..
115 : */
116 : typedef int (*initcall_t)(void);
117 : typedef void (*exitcall_t)(void);
118 :
119 : #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
120 : typedef int initcall_entry_t;
121 :
122 259 : static inline initcall_t initcall_from_entry(initcall_entry_t *entry)
123 : {
124 259 : return offset_to_ptr(entry);
125 : }
126 : #else
127 : typedef initcall_t initcall_entry_t;
128 :
129 : static inline initcall_t initcall_from_entry(initcall_entry_t *entry)
130 : {
131 : return *entry;
132 : }
133 : #endif
134 :
135 : extern initcall_entry_t __con_initcall_start[], __con_initcall_end[];
136 :
137 : /* Used for contructor calls. */
138 : typedef void (*ctor_fn_t)(void);
139 :
140 : struct file_system_type;
141 :
142 : /* Defined in init/main.c */
143 : extern int do_one_initcall(initcall_t fn);
144 : extern char __initdata boot_command_line[];
145 : extern char *saved_command_line;
146 : extern unsigned int reset_devices;
147 :
148 : /* used by init/main.c */
149 : void setup_arch(char **);
150 : void prepare_namespace(void);
151 : void __init init_rootfs(void);
152 : extern struct file_system_type rootfs_fs_type;
153 :
154 : #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
155 : extern bool rodata_enabled;
156 : #endif
157 : #ifdef CONFIG_STRICT_KERNEL_RWX
158 : void mark_rodata_ro(void);
159 : #endif
160 :
161 : extern void (*late_time_init)(void);
162 :
163 : extern bool initcall_debug;
164 :
165 : #endif
166 :
167 : #ifndef MODULE
168 :
169 : #ifndef __ASSEMBLY__
170 :
171 : /*
172 : * initcalls are now grouped by functionality into separate
173 : * subsections. Ordering inside the subsections is determined
174 : * by link order.
175 : * For backwards compatibility, initcall() puts the call in
176 : * the device init subsection.
177 : *
178 : * The `id' arg to __define_initcall() is needed so that multiple initcalls
179 : * can point at the same handler without causing duplicate-symbol build errors.
180 : *
181 : * Initcalls are run by placing pointers in initcall sections that the
182 : * kernel iterates at runtime. The linker can do dead code / data elimination
183 : * and remove that completely, so the initcall sections have to be marked
184 : * as KEEP() in the linker script.
185 : */
186 :
187 : /* Format: <modname>__<counter>_<line>_<fn> */
188 : #define __initcall_id(fn) \
189 : __PASTE(__KBUILD_MODNAME, \
190 : __PASTE(__, \
191 : __PASTE(__COUNTER__, \
192 : __PASTE(_, \
193 : __PASTE(__LINE__, \
194 : __PASTE(_, fn))))))
195 :
196 : /* Format: __<prefix>__<iid><id> */
197 : #define __initcall_name(prefix, __iid, id) \
198 : __PASTE(__, \
199 : __PASTE(prefix, \
200 : __PASTE(__, \
201 : __PASTE(__iid, id))))
202 :
203 : #ifdef CONFIG_LTO_CLANG
204 : /*
205 : * With LTO, the compiler doesn't necessarily obey link order for
206 : * initcalls. In order to preserve the correct order, we add each
207 : * variable into its own section and generate a linker script (in
208 : * scripts/link-vmlinux.sh) to specify the order of the sections.
209 : */
210 : #define __initcall_section(__sec, __iid) \
211 : #__sec ".init.." #__iid
212 :
213 : /*
214 : * With LTO, the compiler can rename static functions to avoid
215 : * global naming collisions. We use a global stub function for
216 : * initcalls to create a stable symbol name whose address can be
217 : * taken in inline assembly when PREL32 relocations are used.
218 : */
219 : #define __initcall_stub(fn, __iid, id) \
220 : __initcall_name(initstub, __iid, id)
221 :
222 : #define __define_initcall_stub(__stub, fn) \
223 : int __init __stub(void); \
224 : int __init __stub(void) \
225 : { \
226 : return fn(); \
227 : } \
228 : __ADDRESSABLE(__stub)
229 : #else
230 : #define __initcall_section(__sec, __iid) \
231 : #__sec ".init"
232 :
233 : #define __initcall_stub(fn, __iid, id) fn
234 :
235 : #define __define_initcall_stub(__stub, fn) \
236 : __ADDRESSABLE(fn)
237 : #endif
238 :
239 : #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
240 : #define ____define_initcall(fn, __stub, __name, __sec) \
241 : __define_initcall_stub(__stub, fn) \
242 : asm(".section \"" __sec "\", \"a\" \n" \
243 : __stringify(__name) ": \n" \
244 : ".long " __stringify(__stub) " - . \n" \
245 : ".previous \n");
246 : #else
247 : #define ____define_initcall(fn, __unused, __name, __sec) \
248 : static initcall_t __name __used \
249 : __attribute__((__section__(__sec))) = fn;
250 : #endif
251 :
252 : #define __unique_initcall(fn, id, __sec, __iid) \
253 : ____define_initcall(fn, \
254 : __initcall_stub(fn, __iid, id), \
255 : __initcall_name(initcall, __iid, id), \
256 : __initcall_section(__sec, __iid))
257 :
258 : #define ___define_initcall(fn, id, __sec) \
259 : __unique_initcall(fn, id, __sec, __initcall_id(fn))
260 :
261 : #define __define_initcall(fn, id) ___define_initcall(fn, id, .initcall##id)
262 :
263 : /*
264 : * Early initcalls run before initializing SMP.
265 : *
266 : * Only for built-in code, not modules.
267 : */
268 : #define early_initcall(fn) __define_initcall(fn, early)
269 :
270 : /*
271 : * A "pure" initcall has no dependencies on anything else, and purely
272 : * initializes variables that couldn't be statically initialized.
273 : *
274 : * This only exists for built-in code, not for modules.
275 : * Keep main.c:initcall_level_names[] in sync.
276 : */
277 : #define pure_initcall(fn) __define_initcall(fn, 0)
278 :
279 : #define core_initcall(fn) __define_initcall(fn, 1)
280 : #define core_initcall_sync(fn) __define_initcall(fn, 1s)
281 : #define postcore_initcall(fn) __define_initcall(fn, 2)
282 : #define postcore_initcall_sync(fn) __define_initcall(fn, 2s)
283 : #define arch_initcall(fn) __define_initcall(fn, 3)
284 : #define arch_initcall_sync(fn) __define_initcall(fn, 3s)
285 : #define subsys_initcall(fn) __define_initcall(fn, 4)
286 : #define subsys_initcall_sync(fn) __define_initcall(fn, 4s)
287 : #define fs_initcall(fn) __define_initcall(fn, 5)
288 : #define fs_initcall_sync(fn) __define_initcall(fn, 5s)
289 : #define rootfs_initcall(fn) __define_initcall(fn, rootfs)
290 : #define device_initcall(fn) __define_initcall(fn, 6)
291 : #define device_initcall_sync(fn) __define_initcall(fn, 6s)
292 : #define late_initcall(fn) __define_initcall(fn, 7)
293 : #define late_initcall_sync(fn) __define_initcall(fn, 7s)
294 :
295 : #define __initcall(fn) device_initcall(fn)
296 :
297 : #define __exitcall(fn) \
298 : static exitcall_t __exitcall_##fn __exit_call = fn
299 :
300 : #define console_initcall(fn) ___define_initcall(fn, con, .con_initcall)
301 :
302 : struct obs_kernel_param {
303 : const char *str;
304 : int (*setup_func)(char *);
305 : int early;
306 : };
307 :
308 : /*
309 : * Only for really core code. See moduleparam.h for the normal way.
310 : *
311 : * Force the alignment so the compiler doesn't space elements of the
312 : * obs_kernel_param "array" too far apart in .init.setup.
313 : */
314 : #define __setup_param(str, unique_id, fn, early) \
315 : static const char __setup_str_##unique_id[] __initconst \
316 : __aligned(1) = str; \
317 : static struct obs_kernel_param __setup_##unique_id \
318 : __used __section(".init.setup") \
319 : __aligned(__alignof__(struct obs_kernel_param)) \
320 : = { __setup_str_##unique_id, fn, early }
321 :
322 : #define __setup(str, fn) \
323 : __setup_param(str, fn, fn, 0)
324 :
325 : /*
326 : * NOTE: fn is as per module_param, not __setup!
327 : * Emits warning if fn returns non-zero.
328 : */
329 : #define early_param(str, fn) \
330 : __setup_param(str, fn, fn, 1)
331 :
332 : #define early_param_on_off(str_on, str_off, var, config) \
333 : \
334 : int var = IS_ENABLED(config); \
335 : \
336 : static int __init parse_##var##_on(char *arg) \
337 : { \
338 : var = 1; \
339 : return 0; \
340 : } \
341 : early_param(str_on, parse_##var##_on); \
342 : \
343 : static int __init parse_##var##_off(char *arg) \
344 : { \
345 : var = 0; \
346 : return 0; \
347 : } \
348 : early_param(str_off, parse_##var##_off)
349 :
350 : /* Relies on boot_command_line being set */
351 : void __init parse_early_param(void);
352 : void __init parse_early_options(char *cmdline);
353 : #endif /* __ASSEMBLY__ */
354 :
355 : #else /* MODULE */
356 :
357 : #define __setup_param(str, unique_id, fn) /* nothing */
358 : #define __setup(str, func) /* nothing */
359 : #endif
360 :
361 : /* Data marked not to be saved by software suspend */
362 : #define __nosavedata __section(".data..nosave")
363 :
364 : #ifdef MODULE
365 : #define __exit_p(x) x
366 : #else
367 : #define __exit_p(x) NULL
368 : #endif
369 :
370 : #endif /* _LINUX_INIT_H */
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