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" 113 114 #define __DEVINIT .section ".devinit.text", "ax" 115 #define __DEVINITDATA .section ".devinit.data", "aw" 116 117 #define __CPUINIT .section ".cpuinit.text", "ax" 118 #define __CPUINITDATA .section ".cpuinit.data", "aw" 119 120 #define __MEMINIT .section ".meminit.text", "ax" 121 #define __MEMINITDATA .section ".meminit.data", "aw" 122 123 /* silence warnings when references are OK */ 124 #define __REF .section ".ref.text", "ax" 125 #define __REFDATA .section ".ref.data", "aw" 126 #define __REFCONST .section ".ref.rodata", "aw" 127 128 #ifndef __ASSEMBLY__ 129 /* 130 * Used for initialization calls.. 131 */ 132 typedef int (*initcall_t)(void); 133 typedef void (*exitcall_t)(void); 134 135 extern initcall_t __con_initcall_start[], __con_initcall_end[]; 136 extern initcall_t __security_initcall_start[], __security_initcall_end[]; 137 138 /* Defined in init/main.c */ 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 #endif 148 149 #ifndef MODULE 150 151 #ifndef __ASSEMBLY__ 152 153 /* initcalls are now grouped by functionality into separate 154 * subsections. Ordering inside the subsections is determined 155 * by link order. 156 * For backwards compatibility, initcall() puts the call in 157 * the device init subsection. 158 * 159 * The `id' arg to __define_initcall() is needed so that multiple initcalls 160 * can point at the same handler without causing duplicate-symbol build errors. 161 */ 162 163 #define __define_initcall(level,fn,id) \ 164 static initcall_t __initcall_##fn##id __used \ 165 __attribute__((__section__(".initcall" level ".init"))) = fn 166 167 /* 168 * A "pure" initcall has no dependencies on anything else, and purely 169 * initializes variables that couldn't be statically initialized. 170 * 171 * This only exists for built-in code, not for modules. 172 */ 173 #define pure_initcall(fn) __define_initcall("0",fn,0) 174 175 #define core_initcall(fn) __define_initcall("1",fn,1) 176 #define core_initcall_sync(fn) __define_initcall("1s",fn,1s) 177 #define postcore_initcall(fn) __define_initcall("2",fn,2) 178 #define postcore_initcall_sync(fn) __define_initcall("2s",fn,2s) 179 #define arch_initcall(fn) __define_initcall("3",fn,3) 180 #define arch_initcall_sync(fn) __define_initcall("3s",fn,3s) 181 #define subsys_initcall(fn) __define_initcall("4",fn,4) 182 #define subsys_initcall_sync(fn) __define_initcall("4s",fn,4s) 183 #define fs_initcall(fn) __define_initcall("5",fn,5) 184 #define fs_initcall_sync(fn) __define_initcall("5s",fn,5s) 185 #define rootfs_initcall(fn) __define_initcall("rootfs",fn,rootfs) 186 #define device_initcall(fn) __define_initcall("6",fn,6) 187 #define device_initcall_sync(fn) __define_initcall("6s",fn,6s) 188 #define late_initcall(fn) __define_initcall("7",fn,7) 189 #define late_initcall_sync(fn) __define_initcall("7s",fn,7s) 190 191 #define __initcall(fn) device_initcall(fn) 192 193 #define __exitcall(fn) \ 194 static exitcall_t __exitcall_##fn __exit_call = fn 195 196 #define console_initcall(fn) \ 197 static initcall_t __initcall_##fn \ 198 __used __section(.con_initcall.init) = fn 199 200 #define security_initcall(fn) \ 201 static initcall_t __initcall_##fn \ 202 __used __section(.security_initcall.init) = fn 203 204 struct obs_kernel_param { 205 const char *str; 206 int (*setup_func)(char *); 207 int early; 208 }; 209 210 /* 211 * Only for really core code. See moduleparam.h for the normal way. 212 * 213 * Force the alignment so the compiler doesn't space elements of the 214 * obs_kernel_param "array" too far apart in .init.setup. 215 */ 216 #define __setup_param(str, unique_id, fn, early) \ 217 static char __setup_str_##unique_id[] __initdata __aligned(1) = str; \ 218 static struct obs_kernel_param __setup_##unique_id \ 219 __used __section(.init.setup) \ 220 __attribute__((aligned((sizeof(long))))) \ 221 = { __setup_str_##unique_id, fn, early } 222 223 #define __setup_null_param(str, unique_id) \ 224 __setup_param(str, unique_id, NULL, 0) 225 226 #define __setup(str, fn) \ 227 __setup_param(str, fn, fn, 0) 228 229 /* NOTE: fn is as per module_param, not __setup! Emits warning if fn 230 * returns non-zero. */ 231 #define early_param(str, fn) \ 232 __setup_param(str, fn, fn, 1) 233 234 /* Relies on boot_command_line being set */ 235 void __init parse_early_param(void); 236 #endif /* __ASSEMBLY__ */ 237 238 /** 239 * module_init() - driver initialization entry point 240 * @x: function to be run at kernel boot time or module insertion 241 * 242 * module_init() will either be called during do_initcalls() (if 243 * builtin) or at module insertion time (if a module). There can only 244 * be one per module. 245 */ 246 #define module_init(x) __initcall(x); 247 248 /** 249 * module_exit() - driver exit entry point 250 * @x: function to be run when driver is removed 251 * 252 * module_exit() will wrap the driver clean-up code 253 * with cleanup_module() when used with rmmod when 254 * the driver is a module. If the driver is statically 255 * compiled into the kernel, module_exit() has no effect. 256 * There can only be one per module. 257 */ 258 #define module_exit(x) __exitcall(x); 259 260 #else /* MODULE */ 261 262 /* Don't use these in modules, but some people do... */ 263 #define core_initcall(fn) module_init(fn) 264 #define postcore_initcall(fn) module_init(fn) 265 #define arch_initcall(fn) module_init(fn) 266 #define subsys_initcall(fn) module_init(fn) 267 #define fs_initcall(fn) module_init(fn) 268 #define device_initcall(fn) module_init(fn) 269 #define late_initcall(fn) module_init(fn) 270 271 #define security_initcall(fn) module_init(fn) 272 273 /* These macros create a dummy inline: gcc 2.9x does not count alias 274 as usage, hence the `unused function' warning when __init functions 275 are declared static. We use the dummy __*_module_inline functions 276 both to kill the warning and check the type of the init/cleanup 277 function. */ 278 279 /* Each module must use one module_init(), or one no_module_init */ 280 #define module_init(initfn) \ 281 static inline initcall_t __inittest(void) \ 282 { return initfn; } \ 283 int init_module(void) __attribute__((alias(#initfn))); 284 285 /* This is only required if you want to be unloadable. */ 286 #define module_exit(exitfn) \ 287 static inline exitcall_t __exittest(void) \ 288 { return exitfn; } \ 289 void cleanup_module(void) __attribute__((alias(#exitfn))); 290 291 #define __setup_param(str, unique_id, fn) /* nothing */ 292 #define __setup_null_param(str, unique_id) /* nothing */ 293 #define __setup(str, func) /* nothing */ 294 #endif 295 296 /* Data marked not to be saved by software suspend */ 297 #define __nosavedata __section(.data.nosave) 298 299 /* This means "can be init if no module support, otherwise module load 300 may call it." */ 301 #ifdef CONFIG_MODULES 302 #define __init_or_module 303 #define __initdata_or_module 304 #else 305 #define __init_or_module __init 306 #define __initdata_or_module __initdata 307 #endif /*CONFIG_MODULES*/ 308 309 /* Functions marked as __devexit may be discarded at kernel link time, depending 310 on config options. Newer versions of binutils detect references from 311 retained sections to discarded sections and flag an error. Pointers to 312 __devexit functions must use __devexit_p(function_name), the wrapper will 313 insert either the function_name or NULL, depending on the config options. 314 */ 315 #if defined(MODULE) || defined(CONFIG_HOTPLUG) 316 #define __devexit_p(x) x 317 #else 318 #define __devexit_p(x) NULL 319 #endif 320 321 #ifdef MODULE 322 #define __exit_p(x) x 323 #else 324 #define __exit_p(x) NULL 325 #endif 326 327 #endif /* _LINUX_INIT_H */ 328