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