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