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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 | extern initcall_t __con_initcall_start[], __con_initcall_end[]; | |
120 | extern initcall_t __security_initcall_start[], __security_initcall_end[]; | |
121 | ||
122 | /* Used for contructor calls. */ | |
123 | typedef void (*ctor_fn_t)(void); | |
124 | ||
125 | /* Defined in init/main.c */ | |
126 | extern int do_one_initcall(initcall_t fn); | |
127 | extern char __initdata boot_command_line[]; | |
128 | extern char *saved_command_line; | |
129 | extern unsigned int reset_devices; | |
130 | ||
131 | /* used by init/main.c */ | |
132 | void setup_arch(char **); | |
133 | void prepare_namespace(void); | |
134 | void __init load_default_modules(void); | |
135 | int __init init_rootfs(void); | |
136 | ||
137 | #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX) | |
138 | extern bool rodata_enabled; | |
139 | #endif | |
140 | #ifdef CONFIG_STRICT_KERNEL_RWX | |
141 | void mark_rodata_ro(void); | |
142 | #endif | |
143 | ||
144 | extern void (*late_time_init)(void); | |
145 | ||
146 | extern bool initcall_debug; | |
147 | ||
148 | #endif | |
149 | ||
150 | #ifndef MODULE | |
151 | ||
152 | #ifndef __ASSEMBLY__ | |
153 | ||
154 | /* | |
155 | * initcalls are now grouped by functionality into separate | |
156 | * subsections. Ordering inside the subsections is determined | |
157 | * by link order. | |
158 | * For backwards compatibility, initcall() puts the call in | |
159 | * the device init subsection. | |
160 | * | |
161 | * The `id' arg to __define_initcall() is needed so that multiple initcalls | |
162 | * can point at the same handler without causing duplicate-symbol build errors. | |
163 | * | |
164 | * Initcalls are run by placing pointers in initcall sections that the | |
165 | * kernel iterates at runtime. The linker can do dead code / data elimination | |
166 | * and remove that completely, so the initcall sections have to be marked | |
167 | * as KEEP() in the linker script. | |
168 | */ | |
169 | ||
170 | #define __define_initcall(fn, id) \ | |
171 | static initcall_t __initcall_##fn##id __used \ | |
172 | __attribute__((__section__(".initcall" #id ".init"))) = fn; | |
173 | ||
174 | /* | |
175 | * Early initcalls run before initializing SMP. | |
176 | * | |
177 | * Only for built-in code, not modules. | |
178 | */ | |
179 | #define early_initcall(fn) __define_initcall(fn, early) | |
180 | ||
181 | /* | |
182 | * A "pure" initcall has no dependencies on anything else, and purely | |
183 | * initializes variables that couldn't be statically initialized. | |
184 | * | |
185 | * This only exists for built-in code, not for modules. | |
186 | * Keep main.c:initcall_level_names[] in sync. | |
187 | */ | |
188 | #define pure_initcall(fn) __define_initcall(fn, 0) | |
189 | ||
190 | #define core_initcall(fn) __define_initcall(fn, 1) | |
191 | #define core_initcall_sync(fn) __define_initcall(fn, 1s) | |
192 | #define postcore_initcall(fn) __define_initcall(fn, 2) | |
193 | #define postcore_initcall_sync(fn) __define_initcall(fn, 2s) | |
194 | #define arch_initcall(fn) __define_initcall(fn, 3) | |
195 | #define arch_initcall_sync(fn) __define_initcall(fn, 3s) | |
196 | #define subsys_initcall(fn) __define_initcall(fn, 4) | |
197 | #define subsys_initcall_sync(fn) __define_initcall(fn, 4s) | |
198 | #define fs_initcall(fn) __define_initcall(fn, 5) | |
199 | #define fs_initcall_sync(fn) __define_initcall(fn, 5s) | |
200 | #define rootfs_initcall(fn) __define_initcall(fn, rootfs) | |
201 | #define device_initcall(fn) __define_initcall(fn, 6) | |
202 | #define device_initcall_sync(fn) __define_initcall(fn, 6s) | |
203 | #define late_initcall(fn) __define_initcall(fn, 7) | |
204 | #define late_initcall_sync(fn) __define_initcall(fn, 7s) | |
205 | ||
206 | #define __initcall(fn) device_initcall(fn) | |
207 | ||
208 | #define __exitcall(fn) \ | |
209 | static exitcall_t __exitcall_##fn __exit_call = fn | |
210 | ||
211 | #define console_initcall(fn) \ | |
212 | static initcall_t __initcall_##fn \ | |
213 | __used __section(.con_initcall.init) = fn | |
214 | ||
215 | #define security_initcall(fn) \ | |
216 | static initcall_t __initcall_##fn \ | |
217 | __used __section(.security_initcall.init) = fn | |
218 | ||
219 | struct obs_kernel_param { | |
220 | const char *str; | |
221 | int (*setup_func)(char *); | |
222 | int early; | |
223 | }; | |
224 | ||
225 | /* | |
226 | * Only for really core code. See moduleparam.h for the normal way. | |
227 | * | |
228 | * Force the alignment so the compiler doesn't space elements of the | |
229 | * obs_kernel_param "array" too far apart in .init.setup. | |
230 | */ | |
231 | #define __setup_param(str, unique_id, fn, early) \ | |
232 | static const char __setup_str_##unique_id[] __initconst \ | |
233 | __aligned(1) = str; \ | |
234 | static struct obs_kernel_param __setup_##unique_id \ | |
235 | __used __section(.init.setup) \ | |
236 | __attribute__((aligned((sizeof(long))))) \ | |
237 | = { __setup_str_##unique_id, fn, early } | |
238 | ||
239 | #define __setup(str, fn) \ | |
240 | __setup_param(str, fn, fn, 0) | |
241 | ||
242 | /* | |
243 | * NOTE: fn is as per module_param, not __setup! | |
244 | * Emits warning if fn returns non-zero. | |
245 | */ | |
246 | #define early_param(str, fn) \ | |
247 | __setup_param(str, fn, fn, 1) | |
248 | ||
249 | #define early_param_on_off(str_on, str_off, var, config) \ | |
250 | \ | |
251 | int var = IS_ENABLED(config); \ | |
252 | \ | |
253 | static int __init parse_##var##_on(char *arg) \ | |
254 | { \ | |
255 | var = 1; \ | |
256 | return 0; \ | |
257 | } \ | |
258 | __setup_param(str_on, parse_##var##_on, parse_##var##_on, 1); \ | |
259 | \ | |
260 | static int __init parse_##var##_off(char *arg) \ | |
261 | { \ | |
262 | var = 0; \ | |
263 | return 0; \ | |
264 | } \ | |
265 | __setup_param(str_off, parse_##var##_off, parse_##var##_off, 1) | |
266 | ||
267 | /* Relies on boot_command_line being set */ | |
268 | void __init parse_early_param(void); | |
269 | void __init parse_early_options(char *cmdline); | |
270 | #endif /* __ASSEMBLY__ */ | |
271 | ||
272 | #else /* MODULE */ | |
273 | ||
274 | #define __setup_param(str, unique_id, fn) /* nothing */ | |
275 | #define __setup(str, func) /* nothing */ | |
276 | #endif | |
277 | ||
278 | /* Data marked not to be saved by software suspend */ | |
279 | #define __nosavedata __section(.data..nosave) | |
280 | ||
281 | #ifdef MODULE | |
282 | #define __exit_p(x) x | |
283 | #else | |
284 | #define __exit_p(x) NULL | |
285 | #endif | |
286 | ||
287 | #endif /* _LINUX_INIT_H */ |