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 __attribute__ ((__section__ (".init.text"))) __cold 44 #define __initdata __attribute__ ((__section__ (".init.data"))) 45 #define __exitdata __attribute__ ((__section__(".exit.data"))) 46 #define __exit_call __attribute_used__ __attribute__ ((__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 modpost 56 * not to issue a warning. 57 * The markers follow same syntax rules as __init / __initdata. */ 58 #define __init_refok noinline __attribute__ ((__section__ (".text.init.refok"))) 59 #define __initdata_refok __attribute__ ((__section__ (".data.init.refok"))) 60 #define __exit_refok noinline __attribute__ ((__section__ (".exit.text.refok"))) 61 62 #ifdef MODULE 63 #define __exit __attribute__ ((__section__(".exit.text"))) __cold 64 #else 65 #define __exit __attribute_used__ __attribute__ ((__section__(".exit.text"))) __cold 66 #endif 67 68 /* For assembly routines */ 69 #define __INIT .section ".init.text","ax" 70 #define __INIT_REFOK .section ".text.init.refok","ax" 71 #define __FINIT .previous 72 #define __INITDATA .section ".init.data","aw" 73 #define __INITDATA_REFOK .section ".data.init.refok","aw" 74 75 #ifndef __ASSEMBLY__ 76 /* 77 * Used for initialization calls.. 78 */ 79 typedef int (*initcall_t)(void); 80 typedef void (*exitcall_t)(void); 81 82 extern initcall_t __con_initcall_start[], __con_initcall_end[]; 83 extern initcall_t __security_initcall_start[], __security_initcall_end[]; 84 85 /* Defined in init/main.c */ 86 extern char __initdata boot_command_line[]; 87 extern char *saved_command_line; 88 extern unsigned int reset_devices; 89 90 /* used by init/main.c */ 91 void setup_arch(char **); 92 void prepare_namespace(void); 93 94 #endif 95 96 #ifndef MODULE 97 98 #ifndef __ASSEMBLY__ 99 100 /* initcalls are now grouped by functionality into separate 101 * subsections. Ordering inside the subsections is determined 102 * by link order. 103 * For backwards compatibility, initcall() puts the call in 104 * the device init subsection. 105 * 106 * The `id' arg to __define_initcall() is needed so that multiple initcalls 107 * can point at the same handler without causing duplicate-symbol build errors. 108 */ 109 110 #define __define_initcall(level,fn,id) \ 111 static initcall_t __initcall_##fn##id __attribute_used__ \ 112 __attribute__((__section__(".initcall" level ".init"))) = fn 113 114 /* 115 * A "pure" initcall has no dependencies on anything else, and purely 116 * initializes variables that couldn't be statically initialized. 117 * 118 * This only exists for built-in code, not for modules. 119 */ 120 #define pure_initcall(fn) __define_initcall("0",fn,0) 121 122 #define core_initcall(fn) __define_initcall("1",fn,1) 123 #define core_initcall_sync(fn) __define_initcall("1s",fn,1s) 124 #define postcore_initcall(fn) __define_initcall("2",fn,2) 125 #define postcore_initcall_sync(fn) __define_initcall("2s",fn,2s) 126 #define arch_initcall(fn) __define_initcall("3",fn,3) 127 #define arch_initcall_sync(fn) __define_initcall("3s",fn,3s) 128 #define subsys_initcall(fn) __define_initcall("4",fn,4) 129 #define subsys_initcall_sync(fn) __define_initcall("4s",fn,4s) 130 #define fs_initcall(fn) __define_initcall("5",fn,5) 131 #define fs_initcall_sync(fn) __define_initcall("5s",fn,5s) 132 #define rootfs_initcall(fn) __define_initcall("rootfs",fn,rootfs) 133 #define device_initcall(fn) __define_initcall("6",fn,6) 134 #define device_initcall_sync(fn) __define_initcall("6s",fn,6s) 135 #define late_initcall(fn) __define_initcall("7",fn,7) 136 #define late_initcall_sync(fn) __define_initcall("7s",fn,7s) 137 138 #define __initcall(fn) device_initcall(fn) 139 140 #define __exitcall(fn) \ 141 static exitcall_t __exitcall_##fn __exit_call = fn 142 143 #define console_initcall(fn) \ 144 static initcall_t __initcall_##fn \ 145 __attribute_used__ __attribute__((__section__(".con_initcall.init")))=fn 146 147 #define security_initcall(fn) \ 148 static initcall_t __initcall_##fn \ 149 __attribute_used__ __attribute__((__section__(".security_initcall.init"))) = fn 150 151 struct obs_kernel_param { 152 const char *str; 153 int (*setup_func)(char *); 154 int early; 155 }; 156 157 /* 158 * Only for really core code. See moduleparam.h for the normal way. 159 * 160 * Force the alignment so the compiler doesn't space elements of the 161 * obs_kernel_param "array" too far apart in .init.setup. 162 */ 163 #define __setup_param(str, unique_id, fn, early) \ 164 static char __setup_str_##unique_id[] __initdata = str; \ 165 static struct obs_kernel_param __setup_##unique_id \ 166 __attribute_used__ \ 167 __attribute__((__section__(".init.setup"))) \ 168 __attribute__((aligned((sizeof(long))))) \ 169 = { __setup_str_##unique_id, fn, early } 170 171 #define __setup_null_param(str, unique_id) \ 172 __setup_param(str, unique_id, NULL, 0) 173 174 #define __setup(str, fn) \ 175 __setup_param(str, fn, fn, 0) 176 177 /* NOTE: fn is as per module_param, not __setup! Emits warning if fn 178 * returns non-zero. */ 179 #define early_param(str, fn) \ 180 __setup_param(str, fn, fn, 1) 181 182 /* Relies on boot_command_line being set */ 183 void __init parse_early_param(void); 184 #endif /* __ASSEMBLY__ */ 185 186 /** 187 * module_init() - driver initialization entry point 188 * @x: function to be run at kernel boot time or module insertion 189 * 190 * module_init() will either be called during do_initcalls() (if 191 * builtin) or at module insertion time (if a module). There can only 192 * be one per module. 193 */ 194 #define module_init(x) __initcall(x); 195 196 /** 197 * module_exit() - driver exit entry point 198 * @x: function to be run when driver is removed 199 * 200 * module_exit() will wrap the driver clean-up code 201 * with cleanup_module() when used with rmmod when 202 * the driver is a module. If the driver is statically 203 * compiled into the kernel, module_exit() has no effect. 204 * There can only be one per module. 205 */ 206 #define module_exit(x) __exitcall(x); 207 208 #else /* MODULE */ 209 210 /* Don't use these in modules, but some people do... */ 211 #define core_initcall(fn) module_init(fn) 212 #define postcore_initcall(fn) module_init(fn) 213 #define arch_initcall(fn) module_init(fn) 214 #define subsys_initcall(fn) module_init(fn) 215 #define fs_initcall(fn) module_init(fn) 216 #define device_initcall(fn) module_init(fn) 217 #define late_initcall(fn) module_init(fn) 218 219 #define security_initcall(fn) module_init(fn) 220 221 /* These macros create a dummy inline: gcc 2.9x does not count alias 222 as usage, hence the `unused function' warning when __init functions 223 are declared static. We use the dummy __*_module_inline functions 224 both to kill the warning and check the type of the init/cleanup 225 function. */ 226 227 /* Each module must use one module_init(), or one no_module_init */ 228 #define module_init(initfn) \ 229 static inline initcall_t __inittest(void) \ 230 { return initfn; } \ 231 int init_module(void) __attribute__((alias(#initfn))); 232 233 /* This is only required if you want to be unloadable. */ 234 #define module_exit(exitfn) \ 235 static inline exitcall_t __exittest(void) \ 236 { return exitfn; } \ 237 void cleanup_module(void) __attribute__((alias(#exitfn))); 238 239 #define __setup_param(str, unique_id, fn) /* nothing */ 240 #define __setup_null_param(str, unique_id) /* nothing */ 241 #define __setup(str, func) /* nothing */ 242 #endif 243 244 /* Data marked not to be saved by software suspend */ 245 #define __nosavedata __attribute__ ((__section__ (".data.nosave"))) 246 247 /* This means "can be init if no module support, otherwise module load 248 may call it." */ 249 #ifdef CONFIG_MODULES 250 #define __init_or_module 251 #define __initdata_or_module 252 #else 253 #define __init_or_module __init 254 #define __initdata_or_module __initdata 255 #endif /*CONFIG_MODULES*/ 256 257 #ifdef CONFIG_HOTPLUG 258 #define __devinit 259 #define __devinitdata 260 #define __devexit 261 #define __devexitdata 262 #else 263 #define __devinit __init 264 #define __devinitdata __initdata 265 #define __devexit __exit 266 #define __devexitdata __exitdata 267 #endif 268 269 #ifdef CONFIG_HOTPLUG_CPU 270 #define __cpuinit 271 #define __cpuinitdata 272 #define __cpuexit 273 #define __cpuexitdata 274 #else 275 #define __cpuinit __init 276 #define __cpuinitdata __initdata 277 #define __cpuexit __exit 278 #define __cpuexitdata __exitdata 279 #endif 280 281 #if defined(CONFIG_MEMORY_HOTPLUG) || defined(CONFIG_ACPI_HOTPLUG_MEMORY) \ 282 || defined(CONFIG_ACPI_HOTPLUG_MEMORY_MODULE) 283 #define __meminit 284 #define __meminitdata 285 #define __memexit 286 #define __memexitdata 287 #else 288 #define __meminit __init 289 #define __meminitdata __initdata 290 #define __memexit __exit 291 #define __memexitdata __exitdata 292 #endif 293 294 /* Functions marked as __devexit may be discarded at kernel link time, depending 295 on config options. Newer versions of binutils detect references from 296 retained sections to discarded sections and flag an error. Pointers to 297 __devexit functions must use __devexit_p(function_name), the wrapper will 298 insert either the function_name or NULL, depending on the config options. 299 */ 300 #if defined(MODULE) || defined(CONFIG_HOTPLUG) 301 #define __devexit_p(x) x 302 #else 303 #define __devexit_p(x) NULL 304 #endif 305 306 #ifdef MODULE 307 #define __exit_p(x) x 308 #else 309 #define __exit_p(x) NULL 310 #endif 311 312 #endif /* _LINUX_INIT_H */ 313