1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef _LINUX_INIT_H |
3 | #define _LINUX_INIT_H |
4 | |
5 | #include <linux/build_bug.h> |
6 | #include <linux/compiler.h> |
7 | #include <linux/stringify.h> |
8 | #include <linux/types.h> |
9 | |
10 | /* Built-in __init functions needn't be compiled with retpoline */ |
11 | #if defined(__noretpoline) && !defined(MODULE) |
12 | #define __noinitretpoline __noretpoline |
13 | #else |
14 | #define __noinitretpoline |
15 | #endif |
16 | |
17 | /* These macros are used to mark some functions or |
18 | * initialized data (doesn't apply to uninitialized data) |
19 | * as `initialization' functions. The kernel can take this |
20 | * as hint that the function is used only during the initialization |
21 | * phase and free up used memory resources after |
22 | * |
23 | * Usage: |
24 | * For functions: |
25 | * |
26 | * You should add __init immediately before the function name, like: |
27 | * |
28 | * static void __init initme(int x, int y) |
29 | * { |
30 | * extern int z; z = x * y; |
31 | * } |
32 | * |
33 | * If the function has a prototype somewhere, you can also add |
34 | * __init between closing brace of the prototype and semicolon: |
35 | * |
36 | * extern int initialize_foobar_device(int, int, int) __init; |
37 | * |
38 | * For initialized data: |
39 | * You should insert __initdata or __initconst between the variable name |
40 | * and equal sign followed by value, e.g.: |
41 | * |
42 | * static int init_variable __initdata = 0; |
43 | * static const char linux_logo[] __initconst = { 0x32, 0x36, ... }; |
44 | * |
45 | * Don't forget to initialize data not at file scope, i.e. within a function, |
46 | * as gcc otherwise puts the data into the bss section and not into the init |
47 | * section. |
48 | */ |
49 | |
50 | /* These are for everybody (although not all archs will actually |
51 | discard it in modules) */ |
52 | #define __init __section(".init.text") __cold __latent_entropy __noinitretpoline |
53 | #define __initdata __section(".init.data") |
54 | #define __initconst __section(".init.rodata") |
55 | #define __exitdata __section(".exit.data") |
56 | #define __exit_call __used __section(".exitcall.exit") |
57 | |
58 | /* |
59 | * modpost check for section mismatches during the kernel build. |
60 | * A section mismatch happens when there are references from a |
61 | * code or data section to an init section (both code or data). |
62 | * The init sections are (for most archs) discarded by the kernel |
63 | * when early init has completed so all such references are potential bugs. |
64 | * For exit sections the same issue exists. |
65 | * |
66 | * The following markers are used for the cases where the reference to |
67 | * the *init / *exit section (code or data) is valid and will teach |
68 | * modpost not to issue a warning. Intended semantics is that a code or |
69 | * data tagged __ref* can reference code or data from init section without |
70 | * producing a warning (of course, no warning does not mean code is |
71 | * correct, so optimally document why the __ref is needed and why it's OK). |
72 | * |
73 | * The markers follow same syntax rules as __init / __initdata. |
74 | */ |
75 | #define __ref __section(".ref.text") noinline |
76 | #define __refdata __section(".ref.data") |
77 | #define __refconst __section(".ref.rodata") |
78 | |
79 | #ifdef MODULE |
80 | #define __exitused |
81 | #else |
82 | #define __exitused __used |
83 | #endif |
84 | |
85 | #define __exit __section(".exit.text") __exitused __cold notrace |
86 | |
87 | /* Used for MEMORY_HOTPLUG */ |
88 | #define __meminit __section(".meminit.text") __cold notrace \ |
89 | __latent_entropy |
90 | #define __meminitdata __section(".meminit.data") |
91 | #define __meminitconst __section(".meminit.rodata") |
92 | |
93 | /* For assembly routines */ |
94 | #define __HEAD .section ".head.text","ax" |
95 | #define __INIT .section ".init.text","ax" |
96 | #define __FINIT .previous |
97 | |
98 | #define __INITDATA .section ".init.data","aw",%progbits |
99 | #define __INITRODATA .section ".init.rodata","a",%progbits |
100 | #define __FINITDATA .previous |
101 | |
102 | #define __MEMINIT .section ".meminit.text", "ax" |
103 | #define __MEMINITDATA .section ".meminit.data", "aw" |
104 | #define __MEMINITRODATA .section ".meminit.rodata", "a" |
105 | |
106 | /* silence warnings when references are OK */ |
107 | #define __REF .section ".ref.text", "ax" |
108 | #define __REFDATA .section ".ref.data", "aw" |
109 | #define __REFCONST .section ".ref.rodata", "a" |
110 | |
111 | #ifndef __ASSEMBLY__ |
112 | /* |
113 | * Used for initialization calls.. |
114 | */ |
115 | typedef int (*initcall_t)(void); |
116 | typedef void (*exitcall_t)(void); |
117 | |
118 | #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS |
119 | typedef int initcall_entry_t; |
120 | |
121 | static inline initcall_t initcall_from_entry(initcall_entry_t *entry) |
122 | { |
123 | return offset_to_ptr(off: entry); |
124 | } |
125 | #else |
126 | typedef initcall_t initcall_entry_t; |
127 | |
128 | static inline initcall_t initcall_from_entry(initcall_entry_t *entry) |
129 | { |
130 | return *entry; |
131 | } |
132 | #endif |
133 | |
134 | extern initcall_entry_t __con_initcall_start[], __con_initcall_end[]; |
135 | |
136 | /* Used for constructor calls. */ |
137 | typedef void (*ctor_fn_t)(void); |
138 | |
139 | struct file_system_type; |
140 | |
141 | /* Defined in init/main.c */ |
142 | extern int do_one_initcall(initcall_t fn); |
143 | extern char __initdata boot_command_line[]; |
144 | extern char *saved_command_line; |
145 | extern unsigned int saved_command_line_len; |
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 | |
153 | void init_IRQ(void); |
154 | void time_init(void); |
155 | void poking_init(void); |
156 | void pgtable_cache_init(void); |
157 | |
158 | extern initcall_entry_t __initcall_start[]; |
159 | extern initcall_entry_t __initcall0_start[]; |
160 | extern initcall_entry_t __initcall1_start[]; |
161 | extern initcall_entry_t __initcall2_start[]; |
162 | extern initcall_entry_t __initcall3_start[]; |
163 | extern initcall_entry_t __initcall4_start[]; |
164 | extern initcall_entry_t __initcall5_start[]; |
165 | extern initcall_entry_t __initcall6_start[]; |
166 | extern initcall_entry_t __initcall7_start[]; |
167 | extern initcall_entry_t __initcall_end[]; |
168 | |
169 | extern struct file_system_type rootfs_fs_type; |
170 | |
171 | #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX) |
172 | extern bool rodata_enabled; |
173 | #endif |
174 | #ifdef CONFIG_STRICT_KERNEL_RWX |
175 | void mark_rodata_ro(void); |
176 | #endif |
177 | |
178 | extern void (*late_time_init)(void); |
179 | |
180 | extern bool initcall_debug; |
181 | |
182 | #endif |
183 | |
184 | #ifndef MODULE |
185 | |
186 | #ifndef __ASSEMBLY__ |
187 | |
188 | /* |
189 | * initcalls are now grouped by functionality into separate |
190 | * subsections. Ordering inside the subsections is determined |
191 | * by link order. |
192 | * For backwards compatibility, initcall() puts the call in |
193 | * the device init subsection. |
194 | * |
195 | * The `id' arg to __define_initcall() is needed so that multiple initcalls |
196 | * can point at the same handler without causing duplicate-symbol build errors. |
197 | * |
198 | * Initcalls are run by placing pointers in initcall sections that the |
199 | * kernel iterates at runtime. The linker can do dead code / data elimination |
200 | * and remove that completely, so the initcall sections have to be marked |
201 | * as KEEP() in the linker script. |
202 | */ |
203 | |
204 | /* Format: <modname>__<counter>_<line>_<fn> */ |
205 | #define __initcall_id(fn) \ |
206 | __PASTE(__KBUILD_MODNAME, \ |
207 | __PASTE(__, \ |
208 | __PASTE(__COUNTER__, \ |
209 | __PASTE(_, \ |
210 | __PASTE(__LINE__, \ |
211 | __PASTE(_, fn)))))) |
212 | |
213 | /* Format: __<prefix>__<iid><id> */ |
214 | #define __initcall_name(prefix, __iid, id) \ |
215 | __PASTE(__, \ |
216 | __PASTE(prefix, \ |
217 | __PASTE(__, \ |
218 | __PASTE(__iid, id)))) |
219 | |
220 | #ifdef CONFIG_LTO_CLANG |
221 | /* |
222 | * With LTO, the compiler doesn't necessarily obey link order for |
223 | * initcalls. In order to preserve the correct order, we add each |
224 | * variable into its own section and generate a linker script (in |
225 | * scripts/link-vmlinux.sh) to specify the order of the sections. |
226 | */ |
227 | #define __initcall_section(__sec, __iid) \ |
228 | #__sec ".init.." #__iid |
229 | |
230 | /* |
231 | * With LTO, the compiler can rename static functions to avoid |
232 | * global naming collisions. We use a global stub function for |
233 | * initcalls to create a stable symbol name whose address can be |
234 | * taken in inline assembly when PREL32 relocations are used. |
235 | */ |
236 | #define __initcall_stub(fn, __iid, id) \ |
237 | __initcall_name(initstub, __iid, id) |
238 | |
239 | #define __define_initcall_stub(__stub, fn) \ |
240 | int __init __stub(void); \ |
241 | int __init __stub(void) \ |
242 | { \ |
243 | return fn(); \ |
244 | } \ |
245 | __ADDRESSABLE(__stub) |
246 | #else |
247 | #define __initcall_section(__sec, __iid) \ |
248 | #__sec ".init" |
249 | |
250 | #define __initcall_stub(fn, __iid, id) fn |
251 | |
252 | #define __define_initcall_stub(__stub, fn) \ |
253 | __ADDRESSABLE(fn) |
254 | #endif |
255 | |
256 | #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS |
257 | #define ____define_initcall(fn, __stub, __name, __sec) \ |
258 | __define_initcall_stub(__stub, fn) \ |
259 | asm(".section \"" __sec "\", \"a\" \n" \ |
260 | __stringify(__name) ": \n" \ |
261 | ".long " __stringify(__stub) " - . \n" \ |
262 | ".previous \n"); \ |
263 | static_assert(__same_type(initcall_t, &fn)); |
264 | #else |
265 | #define ____define_initcall(fn, __unused, __name, __sec) \ |
266 | static initcall_t __name __used \ |
267 | __attribute__((__section__(__sec))) = fn; |
268 | #endif |
269 | |
270 | #define __unique_initcall(fn, id, __sec, __iid) \ |
271 | ____define_initcall(fn, \ |
272 | __initcall_stub(fn, __iid, id), \ |
273 | __initcall_name(initcall, __iid, id), \ |
274 | __initcall_section(__sec, __iid)) |
275 | |
276 | #define ___define_initcall(fn, id, __sec) \ |
277 | __unique_initcall(fn, id, __sec, __initcall_id(fn)) |
278 | |
279 | #define __define_initcall(fn, id) ___define_initcall(fn, id, .initcall##id) |
280 | |
281 | /* |
282 | * Early initcalls run before initializing SMP. |
283 | * |
284 | * Only for built-in code, not modules. |
285 | */ |
286 | #define early_initcall(fn) __define_initcall(fn, early) |
287 | |
288 | /* |
289 | * A "pure" initcall has no dependencies on anything else, and purely |
290 | * initializes variables that couldn't be statically initialized. |
291 | * |
292 | * This only exists for built-in code, not for modules. |
293 | * Keep main.c:initcall_level_names[] in sync. |
294 | */ |
295 | #define pure_initcall(fn) __define_initcall(fn, 0) |
296 | |
297 | #define core_initcall(fn) __define_initcall(fn, 1) |
298 | #define core_initcall_sync(fn) __define_initcall(fn, 1s) |
299 | #define postcore_initcall(fn) __define_initcall(fn, 2) |
300 | #define postcore_initcall_sync(fn) __define_initcall(fn, 2s) |
301 | #define arch_initcall(fn) __define_initcall(fn, 3) |
302 | #define arch_initcall_sync(fn) __define_initcall(fn, 3s) |
303 | #define subsys_initcall(fn) __define_initcall(fn, 4) |
304 | #define subsys_initcall_sync(fn) __define_initcall(fn, 4s) |
305 | #define fs_initcall(fn) __define_initcall(fn, 5) |
306 | #define fs_initcall_sync(fn) __define_initcall(fn, 5s) |
307 | #define rootfs_initcall(fn) __define_initcall(fn, rootfs) |
308 | #define device_initcall(fn) __define_initcall(fn, 6) |
309 | #define device_initcall_sync(fn) __define_initcall(fn, 6s) |
310 | #define late_initcall(fn) __define_initcall(fn, 7) |
311 | #define late_initcall_sync(fn) __define_initcall(fn, 7s) |
312 | |
313 | #define __initcall(fn) device_initcall(fn) |
314 | |
315 | #define __exitcall(fn) \ |
316 | static exitcall_t __exitcall_##fn __exit_call = fn |
317 | |
318 | #define console_initcall(fn) ___define_initcall(fn, con, .con_initcall) |
319 | |
320 | struct obs_kernel_param { |
321 | const char *str; |
322 | int (*setup_func)(char *); |
323 | int early; |
324 | }; |
325 | |
326 | extern const struct obs_kernel_param __setup_start[], __setup_end[]; |
327 | |
328 | /* |
329 | * Only for really core code. See moduleparam.h for the normal way. |
330 | * |
331 | * Force the alignment so the compiler doesn't space elements of the |
332 | * obs_kernel_param "array" too far apart in .init.setup. |
333 | */ |
334 | #define __setup_param(str, unique_id, fn, early) \ |
335 | static const char __setup_str_##unique_id[] __initconst \ |
336 | __aligned(1) = str; \ |
337 | static struct obs_kernel_param __setup_##unique_id \ |
338 | __used __section(".init.setup") \ |
339 | __aligned(__alignof__(struct obs_kernel_param)) \ |
340 | = { __setup_str_##unique_id, fn, early } |
341 | |
342 | /* |
343 | * NOTE: __setup functions return values: |
344 | * @fn returns 1 (or non-zero) if the option argument is "handled" |
345 | * and returns 0 if the option argument is "not handled". |
346 | */ |
347 | #define __setup(str, fn) \ |
348 | __setup_param(str, fn, fn, 0) |
349 | |
350 | /* |
351 | * NOTE: @fn is as per module_param, not __setup! |
352 | * I.e., @fn returns 0 for no error or non-zero for error |
353 | * (possibly @fn returns a -errno value, but it does not matter). |
354 | * Emits warning if @fn returns non-zero. |
355 | */ |
356 | #define early_param(str, fn) \ |
357 | __setup_param(str, fn, fn, 1) |
358 | |
359 | #define early_param_on_off(str_on, str_off, var, config) \ |
360 | \ |
361 | int var = IS_ENABLED(config); \ |
362 | \ |
363 | static int __init parse_##var##_on(char *arg) \ |
364 | { \ |
365 | var = 1; \ |
366 | return 0; \ |
367 | } \ |
368 | early_param(str_on, parse_##var##_on); \ |
369 | \ |
370 | static int __init parse_##var##_off(char *arg) \ |
371 | { \ |
372 | var = 0; \ |
373 | return 0; \ |
374 | } \ |
375 | early_param(str_off, parse_##var##_off) |
376 | |
377 | /* Relies on boot_command_line being set */ |
378 | void __init parse_early_param(void); |
379 | void __init parse_early_options(char *cmdline); |
380 | #endif /* __ASSEMBLY__ */ |
381 | |
382 | #else /* MODULE */ |
383 | |
384 | #define __setup_param(str, unique_id, fn) /* nothing */ |
385 | #define __setup(str, func) /* nothing */ |
386 | #endif |
387 | |
388 | /* Data marked not to be saved by software suspend */ |
389 | #define __nosavedata __section(".data..nosave") |
390 | |
391 | #ifdef MODULE |
392 | #define __exit_p(x) x |
393 | #else |
394 | #define __exit_p(x) NULL |
395 | #endif |
396 | |
397 | #endif /* _LINUX_INIT_H */ |
398 | |