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 /* backward compatibility note 64 * A few places hardcode the old section names: 65 * .text.init.refok 66 * .data.init.refok 67 * .exit.text.refok 68 * They should be converted to use the defines from this file 69 */ 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 84 85 /* Used for HOTPLUG */ 86 #define __devinit __section(.devinit.text) __cold 87 #define __devinitdata __section(.devinit.data) 88 #define __devinitconst __section(.devinit.rodata) 89 #define __devexit __section(.devexit.text) __exitused __cold 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 95 #define __cpuinitdata __section(.cpuinit.data) 96 #define __cpuinitconst __section(.cpuinit.rodata) 97 #define __cpuexit __section(.cpuexit.text) __exitused __cold 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 103 #define __meminitdata __section(.meminit.data) 104 #define __meminitconst __section(.meminit.rodata) 105 #define __memexit __section(.memexit.text) __exitused __cold 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" 115 #define __FINITDATA .previous 116 117 #define __DEVINIT .section ".devinit.text", "ax" 118 #define __DEVINITDATA .section ".devinit.data", "aw" 119 120 #define __CPUINIT .section ".cpuinit.text", "ax" 121 #define __CPUINITDATA .section ".cpuinit.data", "aw" 122 123 #define __MEMINIT .section ".meminit.text", "ax" 124 #define __MEMINITDATA .section ".meminit.data", "aw" 125 126 /* silence warnings when references are OK */ 127 #define __REF .section ".ref.text", "ax" 128 #define __REFDATA .section ".ref.data", "aw" 129 #define __REFCONST .section ".ref.rodata", "aw" 130 131 #ifndef __ASSEMBLY__ 132 /* 133 * Used for initialization calls.. 134 */ 135 typedef int (*initcall_t)(void); 136 typedef void (*exitcall_t)(void); 137 138 extern initcall_t __con_initcall_start[], __con_initcall_end[]; 139 extern initcall_t __security_initcall_start[], __security_initcall_end[]; 140 141 /* Defined in init/main.c */ 142 extern int do_one_initcall(initcall_t fn); 143 extern char __initdata boot_command_line[]; 144 extern char *saved_command_line; 145 extern unsigned int reset_devices; 146 147 /* used by init/main.c */ 148 void setup_arch(char **); 149 void prepare_namespace(void); 150 151 extern void (*late_time_init)(void); 152 153 #endif 154 155 #ifndef MODULE 156 157 #ifndef __ASSEMBLY__ 158 159 /* initcalls are now grouped by functionality into separate 160 * subsections. Ordering inside the subsections is determined 161 * by link order. 162 * For backwards compatibility, initcall() puts the call in 163 * the device init subsection. 164 * 165 * The `id' arg to __define_initcall() is needed so that multiple initcalls 166 * can point at the same handler without causing duplicate-symbol build errors. 167 */ 168 169 #define __define_initcall(level,fn,id) \ 170 static initcall_t __initcall_##fn##id __used \ 171 __attribute__((__section__(".initcall" level ".init"))) = fn 172 173 /* 174 * Early initcalls run before initializing SMP. 175 * 176 * Only for built-in code, not modules. 177 */ 178 #define early_initcall(fn) __define_initcall("early",fn,early) 179 180 /* 181 * A "pure" initcall has no dependencies on anything else, and purely 182 * initializes variables that couldn't be statically initialized. 183 * 184 * This only exists for built-in code, not for modules. 185 */ 186 #define pure_initcall(fn) __define_initcall("0",fn,0) 187 188 #define core_initcall(fn) __define_initcall("1",fn,1) 189 #define core_initcall_sync(fn) __define_initcall("1s",fn,1s) 190 #define postcore_initcall(fn) __define_initcall("2",fn,2) 191 #define postcore_initcall_sync(fn) __define_initcall("2s",fn,2s) 192 #define arch_initcall(fn) __define_initcall("3",fn,3) 193 #define arch_initcall_sync(fn) __define_initcall("3s",fn,3s) 194 #define subsys_initcall(fn) __define_initcall("4",fn,4) 195 #define subsys_initcall_sync(fn) __define_initcall("4s",fn,4s) 196 #define fs_initcall(fn) __define_initcall("5",fn,5) 197 #define fs_initcall_sync(fn) __define_initcall("5s",fn,5s) 198 #define rootfs_initcall(fn) __define_initcall("rootfs",fn,rootfs) 199 #define device_initcall(fn) __define_initcall("6",fn,6) 200 #define device_initcall_sync(fn) __define_initcall("6s",fn,6s) 201 #define late_initcall(fn) __define_initcall("7",fn,7) 202 #define late_initcall_sync(fn) __define_initcall("7s",fn,7s) 203 204 #define __initcall(fn) device_initcall(fn) 205 206 #define __exitcall(fn) \ 207 static exitcall_t __exitcall_##fn __exit_call = fn 208 209 #define console_initcall(fn) \ 210 static initcall_t __initcall_##fn \ 211 __used __section(.con_initcall.init) = fn 212 213 #define security_initcall(fn) \ 214 static initcall_t __initcall_##fn \ 215 __used __section(.security_initcall.init) = fn 216 217 struct obs_kernel_param { 218 const char *str; 219 int (*setup_func)(char *); 220 int early; 221 }; 222 223 /* 224 * Only for really core code. See moduleparam.h for the normal way. 225 * 226 * Force the alignment so the compiler doesn't space elements of the 227 * obs_kernel_param "array" too far apart in .init.setup. 228 */ 229 #define __setup_param(str, unique_id, fn, early) \ 230 static char __setup_str_##unique_id[] __initdata __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 #endif /* __ASSEMBLY__ */ 247 248 /** 249 * module_init() - driver initialization entry point 250 * @x: function to be run at kernel boot time or module insertion 251 * 252 * module_init() will either be called during do_initcalls() (if 253 * builtin) or at module insertion time (if a module). There can only 254 * be one per module. 255 */ 256 #define module_init(x) __initcall(x); 257 258 /** 259 * module_exit() - driver exit entry point 260 * @x: function to be run when driver is removed 261 * 262 * module_exit() will wrap the driver clean-up code 263 * with cleanup_module() when used with rmmod when 264 * the driver is a module. If the driver is statically 265 * compiled into the kernel, module_exit() has no effect. 266 * There can only be one per module. 267 */ 268 #define module_exit(x) __exitcall(x); 269 270 #else /* MODULE */ 271 272 /* Don't use these in modules, but some people do... */ 273 #define core_initcall(fn) module_init(fn) 274 #define postcore_initcall(fn) module_init(fn) 275 #define arch_initcall(fn) module_init(fn) 276 #define subsys_initcall(fn) module_init(fn) 277 #define fs_initcall(fn) module_init(fn) 278 #define device_initcall(fn) module_init(fn) 279 #define late_initcall(fn) module_init(fn) 280 281 #define security_initcall(fn) module_init(fn) 282 283 /* Each module must use one module_init(). */ 284 #define module_init(initfn) \ 285 static inline initcall_t __inittest(void) \ 286 { return initfn; } \ 287 int init_module(void) __attribute__((alias(#initfn))); 288 289 /* This is only required if you want to be unloadable. */ 290 #define module_exit(exitfn) \ 291 static inline exitcall_t __exittest(void) \ 292 { return exitfn; } \ 293 void cleanup_module(void) __attribute__((alias(#exitfn))); 294 295 #define __setup_param(str, unique_id, fn) /* nothing */ 296 #define __setup(str, func) /* nothing */ 297 #endif 298 299 /* Data marked not to be saved by software suspend */ 300 #define __nosavedata __section(.data.nosave) 301 302 /* This means "can be init if no module support, otherwise module load 303 may call it." */ 304 #ifdef CONFIG_MODULES 305 #define __init_or_module 306 #define __initdata_or_module 307 #else 308 #define __init_or_module __init 309 #define __initdata_or_module __initdata 310 #endif /*CONFIG_MODULES*/ 311 312 /* Functions marked as __devexit may be discarded at kernel link time, depending 313 on config options. Newer versions of binutils detect references from 314 retained sections to discarded sections and flag an error. Pointers to 315 __devexit functions must use __devexit_p(function_name), the wrapper will 316 insert either the function_name or NULL, depending on the config options. 317 */ 318 #if defined(MODULE) || defined(CONFIG_HOTPLUG) 319 #define __devexit_p(x) x 320 #else 321 #define __devexit_p(x) NULL 322 #endif 323 324 #ifdef MODULE 325 #define __exit_p(x) x 326 #else 327 #define __exit_p(x) NULL 328 #endif 329 330 #endif /* _LINUX_INIT_H */ 331