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