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 char linux_logo[] __initdata = { 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 /* Defined in init/main.c */ 138 extern int do_one_initcall(initcall_t fn); 139 extern char __initdata boot_command_line[]; 140 extern char *saved_command_line; 141 extern unsigned int reset_devices; 142 143 /* used by init/main.c */ 144 void setup_arch(char **); 145 void prepare_namespace(void); 146 147 extern void (*late_time_init)(void); 148 149 #endif 150 151 #ifndef MODULE 152 153 #ifndef __ASSEMBLY__ 154 155 /* initcalls are now grouped by functionality into separate 156 * subsections. Ordering inside the subsections is determined 157 * by link order. 158 * For backwards compatibility, initcall() puts the call in 159 * the device init subsection. 160 * 161 * The `id' arg to __define_initcall() is needed so that multiple initcalls 162 * can point at the same handler without causing duplicate-symbol build errors. 163 */ 164 165 #define __define_initcall(level,fn,id) \ 166 static initcall_t __initcall_##fn##id __used \ 167 __attribute__((__section__(".initcall" level ".init"))) = fn 168 169 /* 170 * Early initcalls run before initializing SMP. 171 * 172 * Only for built-in code, not modules. 173 */ 174 #define early_initcall(fn) __define_initcall("early",fn,early) 175 176 /* 177 * A "pure" initcall has no dependencies on anything else, and purely 178 * initializes variables that couldn't be statically initialized. 179 * 180 * This only exists for built-in code, not for modules. 181 */ 182 #define pure_initcall(fn) __define_initcall("0",fn,0) 183 184 #define core_initcall(fn) __define_initcall("1",fn,1) 185 #define core_initcall_sync(fn) __define_initcall("1s",fn,1s) 186 #define postcore_initcall(fn) __define_initcall("2",fn,2) 187 #define postcore_initcall_sync(fn) __define_initcall("2s",fn,2s) 188 #define arch_initcall(fn) __define_initcall("3",fn,3) 189 #define arch_initcall_sync(fn) __define_initcall("3s",fn,3s) 190 #define subsys_initcall(fn) __define_initcall("4",fn,4) 191 #define subsys_initcall_sync(fn) __define_initcall("4s",fn,4s) 192 #define fs_initcall(fn) __define_initcall("5",fn,5) 193 #define fs_initcall_sync(fn) __define_initcall("5s",fn,5s) 194 #define rootfs_initcall(fn) __define_initcall("rootfs",fn,rootfs) 195 #define device_initcall(fn) __define_initcall("6",fn,6) 196 #define device_initcall_sync(fn) __define_initcall("6s",fn,6s) 197 #define late_initcall(fn) __define_initcall("7",fn,7) 198 #define late_initcall_sync(fn) __define_initcall("7s",fn,7s) 199 200 #define __initcall(fn) device_initcall(fn) 201 202 #define __exitcall(fn) \ 203 static exitcall_t __exitcall_##fn __exit_call = fn 204 205 #define console_initcall(fn) \ 206 static initcall_t __initcall_##fn \ 207 __used __section(.con_initcall.init) = fn 208 209 #define security_initcall(fn) \ 210 static initcall_t __initcall_##fn \ 211 __used __section(.security_initcall.init) = fn 212 213 struct obs_kernel_param { 214 const char *str; 215 int (*setup_func)(char *); 216 int early; 217 }; 218 219 /* 220 * Only for really core code. See moduleparam.h for the normal way. 221 * 222 * Force the alignment so the compiler doesn't space elements of the 223 * obs_kernel_param "array" too far apart in .init.setup. 224 */ 225 #define __setup_param(str, unique_id, fn, early) \ 226 static const char __setup_str_##unique_id[] __initconst \ 227 __aligned(1) = str; \ 228 static struct obs_kernel_param __setup_##unique_id \ 229 __used __section(.init.setup) \ 230 __attribute__((aligned((sizeof(long))))) \ 231 = { __setup_str_##unique_id, fn, early } 232 233 #define __setup(str, fn) \ 234 __setup_param(str, fn, fn, 0) 235 236 /* NOTE: fn is as per module_param, not __setup! Emits warning if fn 237 * returns non-zero. */ 238 #define early_param(str, fn) \ 239 __setup_param(str, fn, fn, 1) 240 241 /* Relies on boot_command_line being set */ 242 void __init parse_early_param(void); 243 void __init parse_early_options(char *cmdline); 244 #endif /* __ASSEMBLY__ */ 245 246 /** 247 * module_init() - driver initialization entry point 248 * @x: function to be run at kernel boot time or module insertion 249 * 250 * module_init() will either be called during do_initcalls() (if 251 * builtin) or at module insertion time (if a module). There can only 252 * be one per module. 253 */ 254 #define module_init(x) __initcall(x); 255 256 /** 257 * module_exit() - driver exit entry point 258 * @x: function to be run when driver is removed 259 * 260 * module_exit() will wrap the driver clean-up code 261 * with cleanup_module() when used with rmmod when 262 * the driver is a module. If the driver is statically 263 * compiled into the kernel, module_exit() has no effect. 264 * There can only be one per module. 265 */ 266 #define module_exit(x) __exitcall(x); 267 268 #else /* MODULE */ 269 270 /* Don't use these in modules, but some people do... */ 271 #define core_initcall(fn) module_init(fn) 272 #define postcore_initcall(fn) module_init(fn) 273 #define arch_initcall(fn) module_init(fn) 274 #define subsys_initcall(fn) module_init(fn) 275 #define fs_initcall(fn) module_init(fn) 276 #define device_initcall(fn) module_init(fn) 277 #define late_initcall(fn) module_init(fn) 278 279 #define security_initcall(fn) module_init(fn) 280 281 /* Each module must use one module_init(). */ 282 #define module_init(initfn) \ 283 static inline initcall_t __inittest(void) \ 284 { return initfn; } \ 285 int init_module(void) __attribute__((alias(#initfn))); 286 287 /* This is only required if you want to be unloadable. */ 288 #define module_exit(exitfn) \ 289 static inline exitcall_t __exittest(void) \ 290 { return exitfn; } \ 291 void cleanup_module(void) __attribute__((alias(#exitfn))); 292 293 #define __setup_param(str, unique_id, fn) /* nothing */ 294 #define __setup(str, func) /* nothing */ 295 #endif 296 297 /* Data marked not to be saved by software suspend */ 298 #define __nosavedata __section(.data.nosave) 299 300 /* This means "can be init if no module support, otherwise module load 301 may call it." */ 302 #ifdef CONFIG_MODULES 303 #define __init_or_module 304 #define __initdata_or_module 305 #else 306 #define __init_or_module __init 307 #define __initdata_or_module __initdata 308 #endif /*CONFIG_MODULES*/ 309 310 /* Functions marked as __devexit may be discarded at kernel link time, depending 311 on config options. Newer versions of binutils detect references from 312 retained sections to discarded sections and flag an error. Pointers to 313 __devexit functions must use __devexit_p(function_name), the wrapper will 314 insert either the function_name or NULL, depending on the config options. 315 */ 316 #if defined(MODULE) || defined(CONFIG_HOTPLUG) 317 #define __devexit_p(x) x 318 #else 319 #define __devexit_p(x) NULL 320 #endif 321 322 #ifdef MODULE 323 #define __exit_p(x) x 324 #else 325 #define __exit_p(x) NULL 326 #endif 327 328 #endif /* _LINUX_INIT_H */ 329