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 44 #define __initdata __section(.init.data) 45 #define __exitdata __section(.exit.data) 46 #define __exit_call __used __section(.exitcall.exit) 47 48 /* modpost check for section mismatches during the kernel build. 49 * A section mismatch happens when there are references from a 50 * code or data section to an init section (both code or data). 51 * The init sections are (for most archs) discarded by the kernel 52 * when early init has completed so all such references are potential bugs. 53 * For exit sections the same issue exists. 54 * The following markers are used for the cases where the reference to 55 * the *init / *exit section (code or data) is valid and will teach 56 * modpost not to issue a warning. 57 * The markers follow same syntax rules as __init / __initdata. */ 58 #define __ref __section(.ref.text) noinline 59 #define __refdata __section(.ref.data) 60 #define __refconst __section(.ref.rodata) 61 62 /* backward compatibility note 63 * A few places hardcode the old section names: 64 * .text.init.refok 65 * .data.init.refok 66 * .exit.text.refok 67 * They should be converted to use the defines from this file 68 */ 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 __INIT .section ".init.text","ax" 110 #define __FINIT .previous 111 112 #define __INITDATA .section ".init.data","aw" 113 #define __FINITDATA .previous 114 115 #define __DEVINIT .section ".devinit.text", "ax" 116 #define __DEVINITDATA .section ".devinit.data", "aw" 117 118 #define __CPUINIT .section ".cpuinit.text", "ax" 119 #define __CPUINITDATA .section ".cpuinit.data", "aw" 120 121 #define __MEMINIT .section ".meminit.text", "ax" 122 #define __MEMINITDATA .section ".meminit.data", "aw" 123 124 /* silence warnings when references are OK */ 125 #define __REF .section ".ref.text", "ax" 126 #define __REFDATA .section ".ref.data", "aw" 127 #define __REFCONST .section ".ref.rodata", "aw" 128 129 #ifndef __ASSEMBLY__ 130 /* 131 * Used for initialization calls.. 132 */ 133 typedef int (*initcall_t)(void); 134 typedef void (*exitcall_t)(void); 135 136 extern initcall_t __con_initcall_start[], __con_initcall_end[]; 137 extern initcall_t __security_initcall_start[], __security_initcall_end[]; 138 139 /* Defined in init/main.c */ 140 extern char __initdata boot_command_line[]; 141 extern char *saved_command_line; 142 extern unsigned int reset_devices; 143 144 /* used by init/main.c */ 145 void setup_arch(char **); 146 void prepare_namespace(void); 147 148 #endif 149 150 #ifndef MODULE 151 152 #ifndef __ASSEMBLY__ 153 154 /* initcalls are now grouped by functionality into separate 155 * subsections. Ordering inside the subsections is determined 156 * by link order. 157 * For backwards compatibility, initcall() puts the call in 158 * the device init subsection. 159 * 160 * The `id' arg to __define_initcall() is needed so that multiple initcalls 161 * can point at the same handler without causing duplicate-symbol build errors. 162 */ 163 164 #define __define_initcall(level,fn,id) \ 165 static initcall_t __initcall_##fn##id __used \ 166 __attribute__((__section__(".initcall" level ".init"))) = fn 167 168 /* 169 * A "pure" initcall has no dependencies on anything else, and purely 170 * initializes variables that couldn't be statically initialized. 171 * 172 * This only exists for built-in code, not for modules. 173 */ 174 #define pure_initcall(fn) __define_initcall("0",fn,0) 175 176 #define core_initcall(fn) __define_initcall("1",fn,1) 177 #define core_initcall_sync(fn) __define_initcall("1s",fn,1s) 178 #define postcore_initcall(fn) __define_initcall("2",fn,2) 179 #define postcore_initcall_sync(fn) __define_initcall("2s",fn,2s) 180 #define arch_initcall(fn) __define_initcall("3",fn,3) 181 #define arch_initcall_sync(fn) __define_initcall("3s",fn,3s) 182 #define subsys_initcall(fn) __define_initcall("4",fn,4) 183 #define subsys_initcall_sync(fn) __define_initcall("4s",fn,4s) 184 #define fs_initcall(fn) __define_initcall("5",fn,5) 185 #define fs_initcall_sync(fn) __define_initcall("5s",fn,5s) 186 #define rootfs_initcall(fn) __define_initcall("rootfs",fn,rootfs) 187 #define device_initcall(fn) __define_initcall("6",fn,6) 188 #define device_initcall_sync(fn) __define_initcall("6s",fn,6s) 189 #define late_initcall(fn) __define_initcall("7",fn,7) 190 #define late_initcall_sync(fn) __define_initcall("7s",fn,7s) 191 192 #define __initcall(fn) device_initcall(fn) 193 194 #define __exitcall(fn) \ 195 static exitcall_t __exitcall_##fn __exit_call = fn 196 197 #define console_initcall(fn) \ 198 static initcall_t __initcall_##fn \ 199 __used __section(.con_initcall.init) = fn 200 201 #define security_initcall(fn) \ 202 static initcall_t __initcall_##fn \ 203 __used __section(.security_initcall.init) = fn 204 205 struct obs_kernel_param { 206 const char *str; 207 int (*setup_func)(char *); 208 int early; 209 }; 210 211 /* 212 * Only for really core code. See moduleparam.h for the normal way. 213 * 214 * Force the alignment so the compiler doesn't space elements of the 215 * obs_kernel_param "array" too far apart in .init.setup. 216 */ 217 #define __setup_param(str, unique_id, fn, early) \ 218 static char __setup_str_##unique_id[] __initdata __aligned(1) = str; \ 219 static struct obs_kernel_param __setup_##unique_id \ 220 __used __section(.init.setup) \ 221 __attribute__((aligned((sizeof(long))))) \ 222 = { __setup_str_##unique_id, fn, early } 223 224 #define __setup_null_param(str, unique_id) \ 225 __setup_param(str, unique_id, NULL, 0) 226 227 #define __setup(str, fn) \ 228 __setup_param(str, fn, fn, 0) 229 230 /* NOTE: fn is as per module_param, not __setup! Emits warning if fn 231 * returns non-zero. */ 232 #define early_param(str, fn) \ 233 __setup_param(str, fn, fn, 1) 234 235 /* Relies on boot_command_line being set */ 236 void __init parse_early_param(void); 237 #endif /* __ASSEMBLY__ */ 238 239 /** 240 * module_init() - driver initialization entry point 241 * @x: function to be run at kernel boot time or module insertion 242 * 243 * module_init() will either be called during do_initcalls() (if 244 * builtin) or at module insertion time (if a module). There can only 245 * be one per module. 246 */ 247 #define module_init(x) __initcall(x); 248 249 /** 250 * module_exit() - driver exit entry point 251 * @x: function to be run when driver is removed 252 * 253 * module_exit() will wrap the driver clean-up code 254 * with cleanup_module() when used with rmmod when 255 * the driver is a module. If the driver is statically 256 * compiled into the kernel, module_exit() has no effect. 257 * There can only be one per module. 258 */ 259 #define module_exit(x) __exitcall(x); 260 261 #else /* MODULE */ 262 263 /* Don't use these in modules, but some people do... */ 264 #define core_initcall(fn) module_init(fn) 265 #define postcore_initcall(fn) module_init(fn) 266 #define arch_initcall(fn) module_init(fn) 267 #define subsys_initcall(fn) module_init(fn) 268 #define fs_initcall(fn) module_init(fn) 269 #define device_initcall(fn) module_init(fn) 270 #define late_initcall(fn) module_init(fn) 271 272 #define security_initcall(fn) module_init(fn) 273 274 /* These macros create a dummy inline: gcc 2.9x does not count alias 275 as usage, hence the `unused function' warning when __init functions 276 are declared static. We use the dummy __*_module_inline functions 277 both to kill the warning and check the type of the init/cleanup 278 function. */ 279 280 /* Each module must use one module_init(), or one no_module_init */ 281 #define module_init(initfn) \ 282 static inline initcall_t __inittest(void) \ 283 { return initfn; } \ 284 int init_module(void) __attribute__((alias(#initfn))); 285 286 /* This is only required if you want to be unloadable. */ 287 #define module_exit(exitfn) \ 288 static inline exitcall_t __exittest(void) \ 289 { return exitfn; } \ 290 void cleanup_module(void) __attribute__((alias(#exitfn))); 291 292 #define __setup_param(str, unique_id, fn) /* nothing */ 293 #define __setup_null_param(str, unique_id) /* 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