1 #ifndef _LINUX_INIT_H 2 #define _LINUX_INIT_H 3 4 #include <linux/compiler.h> 5 #include <linux/types.h> 6 7 /* These macros are used to mark some functions or 8 * initialized data (doesn't apply to uninitialized data) 9 * as `initialization' functions. The kernel can take this 10 * as hint that the function is used only during the initialization 11 * phase and free up used memory resources after 12 * 13 * Usage: 14 * For functions: 15 * 16 * You should add __init immediately before the function name, like: 17 * 18 * static void __init initme(int x, int y) 19 * { 20 * extern int z; z = x * y; 21 * } 22 * 23 * If the function has a prototype somewhere, you can also add 24 * __init between closing brace of the prototype and semicolon: 25 * 26 * extern int initialize_foobar_device(int, int, int) __init; 27 * 28 * For initialized data: 29 * You should insert __initdata between the variable name and equal 30 * sign followed by value, e.g.: 31 * 32 * static int init_variable __initdata = 0; 33 * static const char linux_logo[] __initconst = { 0x32, 0x36, ... }; 34 * 35 * Don't forget to initialize data not at file scope, i.e. within a function, 36 * as gcc otherwise puts the data into the bss section and not into the init 37 * section. 38 * 39 * Also note, that this data cannot be "const". 40 */ 41 42 /* These are for everybody (although not all archs will actually 43 discard it in modules) */ 44 #define __init __section(.init.text) __cold notrace 45 #define __initdata __section(.init.data) 46 #define __initconst __constsection(.init.rodata) 47 #define __exitdata __section(.exit.data) 48 #define __exit_call __used __section(.exitcall.exit) 49 50 /* 51 * Some architecture have tool chains which do not handle rodata attributes 52 * correctly. For those disable special sections for const, so that other 53 * architectures can annotate correctly. 54 */ 55 #ifdef CONFIG_BROKEN_RODATA 56 #define __constsection(x) 57 #else 58 #define __constsection(x) __section(x) 59 #endif 60 61 /* 62 * modpost check for section mismatches during the kernel build. 63 * A section mismatch happens when there are references from a 64 * code or data section to an init section (both code or data). 65 * The init sections are (for most archs) discarded by the kernel 66 * when early init has completed so all such references are potential bugs. 67 * For exit sections the same issue exists. 68 * 69 * The following markers are used for the cases where the reference to 70 * the *init / *exit section (code or data) is valid and will teach 71 * modpost not to issue a warning. Intended semantics is that a code or 72 * data tagged __ref* can reference code or data from init section without 73 * producing a warning (of course, no warning does not mean code is 74 * correct, so optimally document why the __ref is needed and why it's OK). 75 * 76 * The markers follow same syntax rules as __init / __initdata. 77 */ 78 #define __ref __section(.ref.text) noinline 79 #define __refdata __section(.ref.data) 80 #define __refconst __constsection(.ref.rodata) 81 82 /* compatibility defines */ 83 #define __init_refok __ref 84 #define __initdata_refok __refdata 85 #define __exit_refok __ref 86 87 88 #ifdef MODULE 89 #define __exitused 90 #else 91 #define __exitused __used 92 #endif 93 94 #define __exit __section(.exit.text) __exitused __cold notrace 95 96 /* temporary, until all users are removed */ 97 #define __cpuinit 98 #define __cpuinitdata 99 #define __cpuinitconst 100 #define __cpuexit 101 #define __cpuexitdata 102 #define __cpuexitconst 103 104 /* Used for MEMORY_HOTPLUG */ 105 #define __meminit __section(.meminit.text) __cold notrace 106 #define __meminitdata __section(.meminit.data) 107 #define __meminitconst __constsection(.meminit.rodata) 108 #define __memexit __section(.memexit.text) __exitused __cold notrace 109 #define __memexitdata __section(.memexit.data) 110 #define __memexitconst __constsection(.memexit.rodata) 111 112 /* For assembly routines */ 113 #define __HEAD .section ".head.text","ax" 114 #define __INIT .section ".init.text","ax" 115 #define __FINIT .previous 116 117 #define __INITDATA .section ".init.data","aw",%progbits 118 #define __INITRODATA .section ".init.rodata","a",%progbits 119 #define __FINITDATA .previous 120 121 /* temporary, until all users are removed */ 122 #define __CPUINIT 123 124 #define __MEMINIT .section ".meminit.text", "ax" 125 #define __MEMINITDATA .section ".meminit.data", "aw" 126 #define __MEMINITRODATA .section ".meminit.rodata", "a" 127 128 /* silence warnings when references are OK */ 129 #define __REF .section ".ref.text", "ax" 130 #define __REFDATA .section ".ref.data", "aw" 131 #define __REFCONST .section ".ref.rodata", "a" 132 133 #ifndef __ASSEMBLY__ 134 /* 135 * Used for initialization calls.. 136 */ 137 typedef int (*initcall_t)(void); 138 typedef void (*exitcall_t)(void); 139 140 extern initcall_t __con_initcall_start[], __con_initcall_end[]; 141 extern initcall_t __security_initcall_start[], __security_initcall_end[]; 142 143 /* Used for contructor calls. */ 144 typedef void (*ctor_fn_t)(void); 145 146 /* Defined in init/main.c */ 147 extern int do_one_initcall(initcall_t fn); 148 extern char __initdata boot_command_line[]; 149 extern char *saved_command_line; 150 extern unsigned int reset_devices; 151 152 /* used by init/main.c */ 153 void setup_arch(char **); 154 void prepare_namespace(void); 155 void __init load_default_modules(void); 156 157 extern void (*late_time_init)(void); 158 159 extern bool initcall_debug; 160 161 #endif 162 163 #ifndef MODULE 164 165 #ifndef __ASSEMBLY__ 166 167 /* initcalls are now grouped by functionality into separate 168 * subsections. Ordering inside the subsections is determined 169 * by link order. 170 * For backwards compatibility, initcall() puts the call in 171 * the device init subsection. 172 * 173 * The `id' arg to __define_initcall() is needed so that multiple initcalls 174 * can point at the same handler without causing duplicate-symbol build errors. 175 */ 176 177 #define __define_initcall(fn, id) \ 178 static initcall_t __initcall_##fn##id __used \ 179 __attribute__((__section__(".initcall" #id ".init"))) = fn 180 181 /* 182 * Early initcalls run before initializing SMP. 183 * 184 * Only for built-in code, not modules. 185 */ 186 #define early_initcall(fn) __define_initcall(fn, early) 187 188 /* 189 * A "pure" initcall has no dependencies on anything else, and purely 190 * initializes variables that couldn't be statically initialized. 191 * 192 * This only exists for built-in code, not for modules. 193 * Keep main.c:initcall_level_names[] in sync. 194 */ 195 #define pure_initcall(fn) __define_initcall(fn, 0) 196 197 #define core_initcall(fn) __define_initcall(fn, 1) 198 #define core_initcall_sync(fn) __define_initcall(fn, 1s) 199 #define postcore_initcall(fn) __define_initcall(fn, 2) 200 #define postcore_initcall_sync(fn) __define_initcall(fn, 2s) 201 #define arch_initcall(fn) __define_initcall(fn, 3) 202 #define arch_initcall_sync(fn) __define_initcall(fn, 3s) 203 #define subsys_initcall(fn) __define_initcall(fn, 4) 204 #define subsys_initcall_sync(fn) __define_initcall(fn, 4s) 205 #define fs_initcall(fn) __define_initcall(fn, 5) 206 #define fs_initcall_sync(fn) __define_initcall(fn, 5s) 207 #define rootfs_initcall(fn) __define_initcall(fn, rootfs) 208 #define device_initcall(fn) __define_initcall(fn, 6) 209 #define device_initcall_sync(fn) __define_initcall(fn, 6s) 210 #define late_initcall(fn) __define_initcall(fn, 7) 211 #define late_initcall_sync(fn) __define_initcall(fn, 7s) 212 213 #define __initcall(fn) device_initcall(fn) 214 215 #define __exitcall(fn) \ 216 static exitcall_t __exitcall_##fn __exit_call = fn 217 218 #define console_initcall(fn) \ 219 static initcall_t __initcall_##fn \ 220 __used __section(.con_initcall.init) = fn 221 222 #define security_initcall(fn) \ 223 static initcall_t __initcall_##fn \ 224 __used __section(.security_initcall.init) = fn 225 226 struct obs_kernel_param { 227 const char *str; 228 int (*setup_func)(char *); 229 int early; 230 }; 231 232 /* 233 * Only for really core code. See moduleparam.h for the normal way. 234 * 235 * Force the alignment so the compiler doesn't space elements of the 236 * obs_kernel_param "array" too far apart in .init.setup. 237 */ 238 #define __setup_param(str, unique_id, fn, early) \ 239 static const char __setup_str_##unique_id[] __initconst \ 240 __aligned(1) = str; \ 241 static struct obs_kernel_param __setup_##unique_id \ 242 __used __section(.init.setup) \ 243 __attribute__((aligned((sizeof(long))))) \ 244 = { __setup_str_##unique_id, fn, early } 245 246 #define __setup(str, fn) \ 247 __setup_param(str, fn, fn, 0) 248 249 /* NOTE: fn is as per module_param, not __setup! Emits warning if fn 250 * returns non-zero. */ 251 #define early_param(str, fn) \ 252 __setup_param(str, fn, fn, 1) 253 254 /* Relies on boot_command_line being set */ 255 void __init parse_early_param(void); 256 void __init parse_early_options(char *cmdline); 257 #endif /* __ASSEMBLY__ */ 258 259 /** 260 * module_init() - driver initialization entry point 261 * @x: function to be run at kernel boot time or module insertion 262 * 263 * module_init() will either be called during do_initcalls() (if 264 * builtin) or at module insertion time (if a module). There can only 265 * be one per module. 266 */ 267 #define module_init(x) __initcall(x); 268 269 /** 270 * module_exit() - driver exit entry point 271 * @x: function to be run when driver is removed 272 * 273 * module_exit() will wrap the driver clean-up code 274 * with cleanup_module() when used with rmmod when 275 * the driver is a module. If the driver is statically 276 * compiled into the kernel, module_exit() has no effect. 277 * There can only be one per module. 278 */ 279 #define module_exit(x) __exitcall(x); 280 281 #else /* MODULE */ 282 283 /* Don't use these in loadable modules, but some people do... */ 284 #define early_initcall(fn) module_init(fn) 285 #define core_initcall(fn) module_init(fn) 286 #define postcore_initcall(fn) module_init(fn) 287 #define arch_initcall(fn) module_init(fn) 288 #define subsys_initcall(fn) module_init(fn) 289 #define fs_initcall(fn) module_init(fn) 290 #define device_initcall(fn) module_init(fn) 291 #define late_initcall(fn) module_init(fn) 292 293 #define security_initcall(fn) module_init(fn) 294 295 /* Each module must use one module_init(). */ 296 #define module_init(initfn) \ 297 static inline initcall_t __inittest(void) \ 298 { return initfn; } \ 299 int init_module(void) __attribute__((alias(#initfn))); 300 301 /* This is only required if you want to be unloadable. */ 302 #define module_exit(exitfn) \ 303 static inline exitcall_t __exittest(void) \ 304 { return exitfn; } \ 305 void cleanup_module(void) __attribute__((alias(#exitfn))); 306 307 #define __setup_param(str, unique_id, fn) /* nothing */ 308 #define __setup(str, func) /* nothing */ 309 #endif 310 311 /* Data marked not to be saved by software suspend */ 312 #define __nosavedata __section(.data..nosave) 313 314 /* This means "can be init if no module support, otherwise module load 315 may call it." */ 316 #ifdef CONFIG_MODULES 317 #define __init_or_module 318 #define __initdata_or_module 319 #define __initconst_or_module 320 #define __INIT_OR_MODULE .text 321 #define __INITDATA_OR_MODULE .data 322 #define __INITRODATA_OR_MODULE .section ".rodata","a",%progbits 323 #else 324 #define __init_or_module __init 325 #define __initdata_or_module __initdata 326 #define __initconst_or_module __initconst 327 #define __INIT_OR_MODULE __INIT 328 #define __INITDATA_OR_MODULE __INITDATA 329 #define __INITRODATA_OR_MODULE __INITRODATA 330 #endif /*CONFIG_MODULES*/ 331 332 #ifdef MODULE 333 #define __exit_p(x) x 334 #else 335 #define __exit_p(x) NULL 336 #endif 337 338 #endif /* _LINUX_INIT_H */ 339