1 #ifndef _LINUX_INIT_H 2 #define _LINUX_INIT_H 3 4 #include <linux/compiler.h> 5 #include <linux/types.h> 6 7 /* These macros are used to mark some functions or 8 * initialized data (doesn't apply to uninitialized data) 9 * as `initialization' functions. The kernel can take this 10 * as hint that the function is used only during the initialization 11 * phase and free up used memory resources after 12 * 13 * Usage: 14 * For functions: 15 * 16 * You should add __init immediately before the function name, like: 17 * 18 * static void __init initme(int x, int y) 19 * { 20 * extern int z; z = x * y; 21 * } 22 * 23 * If the function has a prototype somewhere, you can also add 24 * __init between closing brace of the prototype and semicolon: 25 * 26 * extern int initialize_foobar_device(int, int, int) __init; 27 * 28 * For initialized data: 29 * You should insert __initdata or __initconst between the variable name 30 * and equal sign followed by value, e.g.: 31 * 32 * static int init_variable __initdata = 0; 33 * static const char linux_logo[] __initconst = { 0x32, 0x36, ... }; 34 * 35 * Don't forget to initialize data not at file scope, i.e. within a function, 36 * as gcc otherwise puts the data into the bss section and not into the init 37 * section. 38 */ 39 40 /* These are for everybody (although not all archs will actually 41 discard it in modules) */ 42 #define __init __section(.init.text) __cold notrace 43 #define __initdata __section(.init.data) 44 #define __initconst __constsection(.init.rodata) 45 #define __exitdata __section(.exit.data) 46 #define __exit_call __used __section(.exitcall.exit) 47 48 /* 49 * Some architecture have tool chains which do not handle rodata attributes 50 * correctly. For those disable special sections for const, so that other 51 * architectures can annotate correctly. 52 */ 53 #ifdef CONFIG_BROKEN_RODATA 54 #define __constsection(x) 55 #else 56 #define __constsection(x) __section(x) 57 #endif 58 59 /* 60 * modpost check for section mismatches during the kernel build. 61 * A section mismatch happens when there are references from a 62 * code or data section to an init section (both code or data). 63 * The init sections are (for most archs) discarded by the kernel 64 * when early init has completed so all such references are potential bugs. 65 * For exit sections the same issue exists. 66 * 67 * The following markers are used for the cases where the reference to 68 * the *init / *exit section (code or data) is valid and will teach 69 * modpost not to issue a warning. Intended semantics is that a code or 70 * data tagged __ref* can reference code or data from init section without 71 * producing a warning (of course, no warning does not mean code is 72 * correct, so optimally document why the __ref is needed and why it's OK). 73 * 74 * The markers follow same syntax rules as __init / __initdata. 75 */ 76 #define __ref __section(.ref.text) noinline 77 #define __refdata __section(.ref.data) 78 #define __refconst __constsection(.ref.rodata) 79 80 /* compatibility defines */ 81 #define __init_refok __ref 82 #define __initdata_refok __refdata 83 #define __exit_refok __ref 84 85 86 #ifdef MODULE 87 #define __exitused 88 #else 89 #define __exitused __used 90 #endif 91 92 #define __exit __section(.exit.text) __exitused __cold notrace 93 94 /* temporary, until all users are removed */ 95 #define __cpuinit 96 #define __cpuinitdata 97 #define __cpuinitconst 98 #define __cpuexit 99 #define __cpuexitdata 100 #define __cpuexitconst 101 102 /* Used for MEMORY_HOTPLUG */ 103 #define __meminit __section(.meminit.text) __cold notrace 104 #define __meminitdata __section(.meminit.data) 105 #define __meminitconst __constsection(.meminit.rodata) 106 #define __memexit __section(.memexit.text) __exitused __cold notrace 107 #define __memexitdata __section(.memexit.data) 108 #define __memexitconst __constsection(.memexit.rodata) 109 110 /* For assembly routines */ 111 #define __HEAD .section ".head.text","ax" 112 #define __INIT .section ".init.text","ax" 113 #define __FINIT .previous 114 115 #define __INITDATA .section ".init.data","aw",%progbits 116 #define __INITRODATA .section ".init.rodata","a",%progbits 117 #define __FINITDATA .previous 118 119 /* temporary, until all users are removed */ 120 #define __CPUINIT 121 122 #define __MEMINIT .section ".meminit.text", "ax" 123 #define __MEMINITDATA .section ".meminit.data", "aw" 124 #define __MEMINITRODATA .section ".meminit.rodata", "a" 125 126 /* silence warnings when references are OK */ 127 #define __REF .section ".ref.text", "ax" 128 #define __REFDATA .section ".ref.data", "aw" 129 #define __REFCONST .section ".ref.rodata", "a" 130 131 #ifndef __ASSEMBLY__ 132 /* 133 * Used for initialization calls.. 134 */ 135 typedef int (*initcall_t)(void); 136 typedef void (*exitcall_t)(void); 137 138 extern initcall_t __con_initcall_start[], __con_initcall_end[]; 139 extern initcall_t __security_initcall_start[], __security_initcall_end[]; 140 141 /* Used for contructor calls. */ 142 typedef void (*ctor_fn_t)(void); 143 144 /* Defined in init/main.c */ 145 extern int do_one_initcall(initcall_t fn); 146 extern char __initdata boot_command_line[]; 147 extern char *saved_command_line; 148 extern unsigned int reset_devices; 149 150 /* used by init/main.c */ 151 void setup_arch(char **); 152 void prepare_namespace(void); 153 void __init load_default_modules(void); 154 int __init init_rootfs(void); 155 156 extern void (*late_time_init)(void); 157 158 extern bool initcall_debug; 159 160 #endif 161 162 #ifndef MODULE 163 164 #ifndef __ASSEMBLY__ 165 166 #ifdef CONFIG_LTO 167 /* Work around a LTO gcc problem: when there is no reference to a variable 168 * in a module it will be moved to the end of the program. This causes 169 * reordering of initcalls which the kernel does not like. 170 * Add a dummy reference function to avoid this. The function is 171 * deleted by the linker. 172 */ 173 #define LTO_REFERENCE_INITCALL(x) \ 174 ; /* yes this is needed */ \ 175 static __used __exit void *reference_##x(void) \ 176 { \ 177 return &x; \ 178 } 179 #else 180 #define LTO_REFERENCE_INITCALL(x) 181 #endif 182 183 /* initcalls are now grouped by functionality into separate 184 * subsections. Ordering inside the subsections is determined 185 * by link order. 186 * For backwards compatibility, initcall() puts the call in 187 * the device init subsection. 188 * 189 * The `id' arg to __define_initcall() is needed so that multiple initcalls 190 * can point at the same handler without causing duplicate-symbol build errors. 191 */ 192 193 #define __define_initcall(fn, id) \ 194 static initcall_t __initcall_##fn##id __used \ 195 __attribute__((__section__(".initcall" #id ".init"))) = fn; \ 196 LTO_REFERENCE_INITCALL(__initcall_##fn##id) 197 198 /* 199 * Early initcalls run before initializing SMP. 200 * 201 * Only for built-in code, not modules. 202 */ 203 #define early_initcall(fn) __define_initcall(fn, early) 204 205 /* 206 * A "pure" initcall has no dependencies on anything else, and purely 207 * initializes variables that couldn't be statically initialized. 208 * 209 * This only exists for built-in code, not for modules. 210 * Keep main.c:initcall_level_names[] in sync. 211 */ 212 #define pure_initcall(fn) __define_initcall(fn, 0) 213 214 #define core_initcall(fn) __define_initcall(fn, 1) 215 #define core_initcall_sync(fn) __define_initcall(fn, 1s) 216 #define postcore_initcall(fn) __define_initcall(fn, 2) 217 #define postcore_initcall_sync(fn) __define_initcall(fn, 2s) 218 #define arch_initcall(fn) __define_initcall(fn, 3) 219 #define arch_initcall_sync(fn) __define_initcall(fn, 3s) 220 #define subsys_initcall(fn) __define_initcall(fn, 4) 221 #define subsys_initcall_sync(fn) __define_initcall(fn, 4s) 222 #define fs_initcall(fn) __define_initcall(fn, 5) 223 #define fs_initcall_sync(fn) __define_initcall(fn, 5s) 224 #define rootfs_initcall(fn) __define_initcall(fn, rootfs) 225 #define device_initcall(fn) __define_initcall(fn, 6) 226 #define device_initcall_sync(fn) __define_initcall(fn, 6s) 227 #define late_initcall(fn) __define_initcall(fn, 7) 228 #define late_initcall_sync(fn) __define_initcall(fn, 7s) 229 230 #define __initcall(fn) device_initcall(fn) 231 232 #define __exitcall(fn) \ 233 static exitcall_t __exitcall_##fn __exit_call = fn 234 235 #define console_initcall(fn) \ 236 static initcall_t __initcall_##fn \ 237 __used __section(.con_initcall.init) = fn 238 239 #define security_initcall(fn) \ 240 static initcall_t __initcall_##fn \ 241 __used __section(.security_initcall.init) = fn 242 243 struct obs_kernel_param { 244 const char *str; 245 int (*setup_func)(char *); 246 int early; 247 }; 248 249 /* 250 * Only for really core code. See moduleparam.h for the normal way. 251 * 252 * Force the alignment so the compiler doesn't space elements of the 253 * obs_kernel_param "array" too far apart in .init.setup. 254 */ 255 #define __setup_param(str, unique_id, fn, early) \ 256 static const char __setup_str_##unique_id[] __initconst \ 257 __aligned(1) = str; \ 258 static struct obs_kernel_param __setup_##unique_id \ 259 __used __section(.init.setup) \ 260 __attribute__((aligned((sizeof(long))))) \ 261 = { __setup_str_##unique_id, fn, early } 262 263 #define __setup(str, fn) \ 264 __setup_param(str, fn, fn, 0) 265 266 /* NOTE: fn is as per module_param, not __setup! Emits warning if fn 267 * returns non-zero. */ 268 #define early_param(str, fn) \ 269 __setup_param(str, fn, fn, 1) 270 271 /* Relies on boot_command_line being set */ 272 void __init parse_early_param(void); 273 void __init parse_early_options(char *cmdline); 274 #endif /* __ASSEMBLY__ */ 275 276 /** 277 * module_init() - driver initialization entry point 278 * @x: function to be run at kernel boot time or module insertion 279 * 280 * module_init() will either be called during do_initcalls() (if 281 * builtin) or at module insertion time (if a module). There can only 282 * be one per module. 283 */ 284 #define module_init(x) __initcall(x); 285 286 /** 287 * module_exit() - driver exit entry point 288 * @x: function to be run when driver is removed 289 * 290 * module_exit() will wrap the driver clean-up code 291 * with cleanup_module() when used with rmmod when 292 * the driver is a module. If the driver is statically 293 * compiled into the kernel, module_exit() has no effect. 294 * There can only be one per module. 295 */ 296 #define module_exit(x) __exitcall(x); 297 298 #else /* MODULE */ 299 300 /* 301 * In most cases loadable modules do not need custom 302 * initcall levels. There are still some valid cases where 303 * a driver may be needed early if built in, and does not 304 * matter when built as a loadable module. Like bus 305 * snooping debug drivers. 306 */ 307 #define early_initcall(fn) module_init(fn) 308 #define core_initcall(fn) module_init(fn) 309 #define core_initcall_sync(fn) module_init(fn) 310 #define postcore_initcall(fn) module_init(fn) 311 #define postcore_initcall_sync(fn) module_init(fn) 312 #define arch_initcall(fn) module_init(fn) 313 #define subsys_initcall(fn) module_init(fn) 314 #define subsys_initcall_sync(fn) module_init(fn) 315 #define fs_initcall(fn) module_init(fn) 316 #define fs_initcall_sync(fn) module_init(fn) 317 #define rootfs_initcall(fn) module_init(fn) 318 #define device_initcall(fn) module_init(fn) 319 #define device_initcall_sync(fn) module_init(fn) 320 #define late_initcall(fn) module_init(fn) 321 #define late_initcall_sync(fn) module_init(fn) 322 323 #define console_initcall(fn) module_init(fn) 324 #define security_initcall(fn) module_init(fn) 325 326 /* Each module must use one module_init(). */ 327 #define module_init(initfn) \ 328 static inline initcall_t __inittest(void) \ 329 { return initfn; } \ 330 int init_module(void) __attribute__((alias(#initfn))); 331 332 /* This is only required if you want to be unloadable. */ 333 #define module_exit(exitfn) \ 334 static inline exitcall_t __exittest(void) \ 335 { return exitfn; } \ 336 void cleanup_module(void) __attribute__((alias(#exitfn))); 337 338 #define __setup_param(str, unique_id, fn) /* nothing */ 339 #define __setup(str, func) /* nothing */ 340 #endif 341 342 /* Data marked not to be saved by software suspend */ 343 #define __nosavedata __section(.data..nosave) 344 345 /* This means "can be init if no module support, otherwise module load 346 may call it." */ 347 #ifdef CONFIG_MODULES 348 #define __init_or_module 349 #define __initdata_or_module 350 #define __initconst_or_module 351 #define __INIT_OR_MODULE .text 352 #define __INITDATA_OR_MODULE .data 353 #define __INITRODATA_OR_MODULE .section ".rodata","a",%progbits 354 #else 355 #define __init_or_module __init 356 #define __initdata_or_module __initdata 357 #define __initconst_or_module __initconst 358 #define __INIT_OR_MODULE __INIT 359 #define __INITDATA_OR_MODULE __INITDATA 360 #define __INITRODATA_OR_MODULE __INITRODATA 361 #endif /*CONFIG_MODULES*/ 362 363 #ifdef MODULE 364 #define __exit_p(x) x 365 #else 366 #define __exit_p(x) NULL 367 #endif 368 369 #endif /* _LINUX_INIT_H */ 370