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