1 #ifndef _LINUX_INIT_H 2 #define _LINUX_INIT_H 3 4 #include <linux/compiler.h> 5 #include <linux/types.h> 6 7 /* Built-in __init functions needn't be compiled with retpoline */ 8 #if defined(__noretpoline) && !defined(MODULE) 9 #define __noinitretpoline __noretpoline 10 #else 11 #define __noinitretpoline 12 #endif 13 14 /* These macros are used to mark some functions or 15 * initialized data (doesn't apply to uninitialized data) 16 * as `initialization' functions. The kernel can take this 17 * as hint that the function is used only during the initialization 18 * phase and free up used memory resources after 19 * 20 * Usage: 21 * For functions: 22 * 23 * You should add __init immediately before the function name, like: 24 * 25 * static void __init initme(int x, int y) 26 * { 27 * extern int z; z = x * y; 28 * } 29 * 30 * If the function has a prototype somewhere, you can also add 31 * __init between closing brace of the prototype and semicolon: 32 * 33 * extern int initialize_foobar_device(int, int, int) __init; 34 * 35 * For initialized data: 36 * You should insert __initdata or __initconst between the variable name 37 * and equal sign followed by value, e.g.: 38 * 39 * static int init_variable __initdata = 0; 40 * static const char linux_logo[] __initconst = { 0x32, 0x36, ... }; 41 * 42 * Don't forget to initialize data not at file scope, i.e. within a function, 43 * as gcc otherwise puts the data into the bss section and not into the init 44 * section. 45 */ 46 47 /* These are for everybody (although not all archs will actually 48 discard it in modules) */ 49 #define __init __section(.init.text) __cold notrace __latent_entropy __noinitretpoline __nocfi 50 #define __initdata __section(.init.data) 51 #define __initconst __section(.init.rodata) 52 #define __exitdata __section(.exit.data) 53 #define __exit_call __used __section(.exitcall.exit) 54 55 /* 56 * modpost check for section mismatches during the kernel build. 57 * A section mismatch happens when there are references from a 58 * code or data section to an init section (both code or data). 59 * The init sections are (for most archs) discarded by the kernel 60 * when early init has completed so all such references are potential bugs. 61 * For exit sections the same issue exists. 62 * 63 * The following markers are used for the cases where the reference to 64 * the *init / *exit section (code or data) is valid and will teach 65 * modpost not to issue a warning. Intended semantics is that a code or 66 * data tagged __ref* can reference code or data from init section without 67 * producing a warning (of course, no warning does not mean code is 68 * correct, so optimally document why the __ref is needed and why it's OK). 69 * 70 * The markers follow same syntax rules as __init / __initdata. 71 */ 72 #define __ref __section(.ref.text) noinline 73 #define __refdata __section(.ref.data) 74 #define __refconst __section(.ref.rodata) 75 76 #ifdef MODULE 77 #define __exitused 78 #else 79 #define __exitused __used 80 #endif 81 82 #define __exit __section(.exit.text) __exitused __cold notrace 83 84 /* Used for MEMORY_HOTPLUG */ 85 #define __meminit __section(.meminit.text) __cold notrace \ 86 __latent_entropy 87 #define __meminitdata __section(.meminit.data) 88 #define __meminitconst __section(.meminit.rodata) 89 #define __memexit __section(.memexit.text) __exitused __cold notrace 90 #define __memexitdata __section(.memexit.data) 91 #define __memexitconst __section(.memexit.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 extern initcall_t __con_initcall_start[], __con_initcall_end[]; 119 extern initcall_t __security_initcall_start[], __security_initcall_end[]; 120 121 /* Used for contructor calls. */ 122 typedef void (*ctor_fn_t)(void); 123 124 /* Defined in init/main.c */ 125 extern int do_one_initcall(initcall_t fn); 126 extern char __initdata boot_command_line[]; 127 extern char *saved_command_line; 128 extern unsigned int reset_devices; 129 130 /* used by init/main.c */ 131 void setup_arch(char **); 132 void prepare_namespace(void); 133 void __init load_default_modules(void); 134 int __init init_rootfs(void); 135 136 #if defined(CONFIG_DEBUG_RODATA) || defined(CONFIG_DEBUG_SET_MODULE_RONX) 137 extern bool rodata_enabled; 138 #endif 139 #ifdef CONFIG_DEBUG_RODATA 140 void mark_rodata_ro(void); 141 #endif 142 143 extern void (*late_time_init)(void); 144 145 extern bool initcall_debug; 146 147 #endif 148 149 #ifndef MODULE 150 151 #ifndef __ASSEMBLY__ 152 153 #ifdef CONFIG_LTO_CLANG 154 /* prepend the variable name with __COUNTER__ to ensure correct ordering */ 155 #define ___initcall_name2(c, fn, id) __initcall_##c##_##fn##id 156 #define ___initcall_name1(c, fn, id) ___initcall_name2(c, fn, id) 157 #define __initcall_name(fn, id) ___initcall_name1(__COUNTER__, fn, id) 158 #else 159 #define __initcall_name(fn, id) __initcall_##fn##id 160 #endif 161 162 /* 163 * initcalls are now grouped by functionality into separate 164 * subsections. Ordering inside the subsections is determined 165 * by link order. 166 * For backwards compatibility, initcall() puts the call in 167 * the device init subsection. 168 * 169 * The `id' arg to __define_initcall() is needed so that multiple initcalls 170 * can point at the same handler without causing duplicate-symbol build errors. 171 * 172 * Initcalls are run by placing pointers in initcall sections that the 173 * kernel iterates at runtime. The linker can do dead code / data elimination 174 * and remove that completely, so the initcall sections have to be marked 175 * as KEEP() in the linker script. 176 */ 177 178 #define __define_initcall(fn, id) \ 179 static initcall_t __initcall_name(fn, id) __used \ 180 __attribute__((__section__(".initcall" #id ".init"))) = fn; 181 182 /* 183 * Early initcalls run before initializing SMP. 184 * 185 * Only for built-in code, not modules. 186 */ 187 #define early_initcall(fn) __define_initcall(fn, early) 188 189 /* 190 * A "pure" initcall has no dependencies on anything else, and purely 191 * initializes variables that couldn't be statically initialized. 192 * 193 * This only exists for built-in code, not for modules. 194 * Keep main.c:initcall_level_names[] in sync. 195 */ 196 #define pure_initcall(fn) __define_initcall(fn, 0) 197 198 #define core_initcall(fn) __define_initcall(fn, 1) 199 #define core_initcall_sync(fn) __define_initcall(fn, 1s) 200 #define postcore_initcall(fn) __define_initcall(fn, 2) 201 #define postcore_initcall_sync(fn) __define_initcall(fn, 2s) 202 #define arch_initcall(fn) __define_initcall(fn, 3) 203 #define arch_initcall_sync(fn) __define_initcall(fn, 3s) 204 #define subsys_initcall(fn) __define_initcall(fn, 4) 205 #define subsys_initcall_sync(fn) __define_initcall(fn, 4s) 206 #define fs_initcall(fn) __define_initcall(fn, 5) 207 #define fs_initcall_sync(fn) __define_initcall(fn, 5s) 208 #define rootfs_initcall(fn) __define_initcall(fn, rootfs) 209 #define device_initcall(fn) __define_initcall(fn, 6) 210 #define device_initcall_sync(fn) __define_initcall(fn, 6s) 211 #define late_initcall(fn) __define_initcall(fn, 7) 212 #define late_initcall_sync(fn) __define_initcall(fn, 7s) 213 214 #define __initcall(fn) device_initcall(fn) 215 216 #define __exitcall(fn) \ 217 static exitcall_t __exitcall_##fn __exit_call = fn 218 219 #define console_initcall(fn) \ 220 static initcall_t __initcall_##fn \ 221 __used __section(.con_initcall.init) = fn 222 223 #define security_initcall(fn) \ 224 static initcall_t __initcall_##fn \ 225 __used __section(.security_initcall.init) = fn 226 227 struct obs_kernel_param { 228 const char *str; 229 int (*setup_func)(char *); 230 int early; 231 }; 232 233 /* 234 * Only for really core code. See moduleparam.h for the normal way. 235 * 236 * Force the alignment so the compiler doesn't space elements of the 237 * obs_kernel_param "array" too far apart in .init.setup. 238 */ 239 #define __setup_param(str, unique_id, fn, early) \ 240 static const char __setup_str_##unique_id[] __initconst \ 241 __aligned(1) = str; \ 242 static struct obs_kernel_param __setup_##unique_id \ 243 __used __section(.init.setup) \ 244 __attribute__((aligned((sizeof(long))))) \ 245 = { __setup_str_##unique_id, fn, early } 246 247 #define __setup(str, fn) \ 248 __setup_param(str, fn, fn, 0) 249 250 /* 251 * NOTE: fn is as per module_param, not __setup! 252 * Emits warning if fn returns non-zero. 253 */ 254 #define early_param(str, fn) \ 255 __setup_param(str, fn, fn, 1) 256 257 #define early_param_on_off(str_on, str_off, var, config) \ 258 \ 259 int var = IS_ENABLED(config); \ 260 \ 261 static int __init parse_##var##_on(char *arg) \ 262 { \ 263 var = 1; \ 264 return 0; \ 265 } \ 266 __setup_param(str_on, parse_##var##_on, parse_##var##_on, 1); \ 267 \ 268 static int __init parse_##var##_off(char *arg) \ 269 { \ 270 var = 0; \ 271 return 0; \ 272 } \ 273 __setup_param(str_off, parse_##var##_off, parse_##var##_off, 1) 274 275 /* Relies on boot_command_line being set */ 276 void __init parse_early_param(void); 277 void __init parse_early_options(char *cmdline); 278 #endif /* __ASSEMBLY__ */ 279 280 #else /* MODULE */ 281 282 #define __setup_param(str, unique_id, fn) /* nothing */ 283 #define __setup(str, func) /* nothing */ 284 #endif 285 286 /* Data marked not to be saved by software suspend */ 287 #define __nosavedata __section(.data..nosave) 288 289 #ifdef MODULE 290 #define __exit_p(x) x 291 #else 292 #define __exit_p(x) NULL 293 #endif 294 295 #endif /* _LINUX_INIT_H */ 296