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 __nocfi |
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 | static inline initcall_t initcall_from_entry(initcall_entry_t *entry) |
123 | { |
124 | 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 __cficanonical __stub(void); \ |
224 | int __init __cficanonical __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 | static_assert(__same_type(initcall_t, &fn)); |
247 | #else |
248 | #define ____define_initcall(fn, __unused, __name, __sec) \ |
249 | static initcall_t __name __used \ |
250 | __attribute__((__section__(__sec))) = fn; |
251 | #endif |
252 | |
253 | #define __unique_initcall(fn, id, __sec, __iid) \ |
254 | ____define_initcall(fn, \ |
255 | __initcall_stub(fn, __iid, id), \ |
256 | __initcall_name(initcall, __iid, id), \ |
257 | __initcall_section(__sec, __iid)) |
258 | |
259 | #define ___define_initcall(fn, id, __sec) \ |
260 | __unique_initcall(fn, id, __sec, __initcall_id(fn)) |
261 | |
262 | #define __define_initcall(fn, id) ___define_initcall(fn, id, .initcall##id) |
263 | |
264 | /* |
265 | * Early initcalls run before initializing SMP. |
266 | * |
267 | * Only for built-in code, not modules. |
268 | */ |
269 | #define early_initcall(fn) __define_initcall(fn, early) |
270 | |
271 | /* |
272 | * A "pure" initcall has no dependencies on anything else, and purely |
273 | * initializes variables that couldn't be statically initialized. |
274 | * |
275 | * This only exists for built-in code, not for modules. |
276 | * Keep main.c:initcall_level_names[] in sync. |
277 | */ |
278 | #define pure_initcall(fn) __define_initcall(fn, 0) |
279 | |
280 | #define core_initcall(fn) __define_initcall(fn, 1) |
281 | #define core_initcall_sync(fn) __define_initcall(fn, 1s) |
282 | #define postcore_initcall(fn) __define_initcall(fn, 2) |
283 | #define postcore_initcall_sync(fn) __define_initcall(fn, 2s) |
284 | #define arch_initcall(fn) __define_initcall(fn, 3) |
285 | #define arch_initcall_sync(fn) __define_initcall(fn, 3s) |
286 | #define subsys_initcall(fn) __define_initcall(fn, 4) |
287 | #define subsys_initcall_sync(fn) __define_initcall(fn, 4s) |
288 | #define fs_initcall(fn) __define_initcall(fn, 5) |
289 | #define fs_initcall_sync(fn) __define_initcall(fn, 5s) |
290 | #define rootfs_initcall(fn) __define_initcall(fn, rootfs) |
291 | #define device_initcall(fn) __define_initcall(fn, 6) |
292 | #define device_initcall_sync(fn) __define_initcall(fn, 6s) |
293 | #define late_initcall(fn) __define_initcall(fn, 7) |
294 | #define late_initcall_sync(fn) __define_initcall(fn, 7s) |
295 | |
296 | #define __initcall(fn) device_initcall(fn) |
297 | |
298 | #define __exitcall(fn) \ |
299 | static exitcall_t __exitcall_##fn __exit_call = fn |
300 | |
301 | #define console_initcall(fn) ___define_initcall(fn, con, .con_initcall) |
302 | |
303 | struct obs_kernel_param { |
304 | const char *str; |
305 | int (*setup_func)(char *); |
306 | int early; |
307 | }; |
308 | |
309 | /* |
310 | * Only for really core code. See moduleparam.h for the normal way. |
311 | * |
312 | * Force the alignment so the compiler doesn't space elements of the |
313 | * obs_kernel_param "array" too far apart in .init.setup. |
314 | */ |
315 | #define __setup_param(str, unique_id, fn, early) \ |
316 | static const char __setup_str_##unique_id[] __initconst \ |
317 | __aligned(1) = str; \ |
318 | static struct obs_kernel_param __setup_##unique_id \ |
319 | __used __section(".init.setup") \ |
320 | __aligned(__alignof__(struct obs_kernel_param)) \ |
321 | = { __setup_str_##unique_id, fn, early } |
322 | |
323 | /* |
324 | * NOTE: __setup functions return values: |
325 | * @fn returns 1 (or non-zero) if the option argument is "handled" |
326 | * and returns 0 if the option argument is "not handled". |
327 | */ |
328 | #define __setup(str, fn) \ |
329 | __setup_param(str, fn, fn, 0) |
330 | |
331 | /* |
332 | * NOTE: @fn is as per module_param, not __setup! |
333 | * I.e., @fn returns 0 for no error or non-zero for error |
334 | * (possibly @fn returns a -errno value, but it does not matter). |
335 | * Emits warning if @fn returns non-zero. |
336 | */ |
337 | #define early_param(str, fn) \ |
338 | __setup_param(str, fn, fn, 1) |
339 | |
340 | #define early_param_on_off(str_on, str_off, var, config) \ |
341 | \ |
342 | int var = IS_ENABLED(config); \ |
343 | \ |
344 | static int __init parse_##var##_on(char *arg) \ |
345 | { \ |
346 | var = 1; \ |
347 | return 0; \ |
348 | } \ |
349 | early_param(str_on, parse_##var##_on); \ |
350 | \ |
351 | static int __init parse_##var##_off(char *arg) \ |
352 | { \ |
353 | var = 0; \ |
354 | return 0; \ |
355 | } \ |
356 | early_param(str_off, parse_##var##_off) |
357 | |
358 | /* Relies on boot_command_line being set */ |
359 | void __init parse_early_param(void); |
360 | void __init parse_early_options(char *cmdline); |
361 | #endif /* __ASSEMBLY__ */ |
362 | |
363 | #else /* MODULE */ |
364 | |
365 | #define __setup_param(str, unique_id, fn) /* nothing */ |
366 | #define __setup(str, func) /* nothing */ |
367 | #endif |
368 | |
369 | /* Data marked not to be saved by software suspend */ |
370 | #define __nosavedata __section(".data..nosave") |
371 | |
372 | #ifdef MODULE |
373 | #define __exit_p(x) x |
374 | #else |
375 | #define __exit_p(x) NULL |
376 | #endif |
377 | |
378 | #endif /* _LINUX_INIT_H */ |
379 | |