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