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 or __initconst between the variable name 30 * and equal 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 40/* These are for everybody (although not all archs will actually 41 discard it in modules) */ 42#define __init __section(.init.text) __cold notrace 43#define __initdata __section(.init.data) 44#define __initconst __constsection(.init.rodata) 45#define __exitdata __section(.exit.data) 46#define __exit_call __used __section(.exitcall.exit) 47 48/* 49 * Some architecture have tool chains which do not handle rodata attributes 50 * correctly. For those disable special sections for const, so that other 51 * architectures can annotate correctly. 52 */ 53#ifdef CONFIG_BROKEN_RODATA 54#define __constsection(x) 55#else 56#define __constsection(x) __section(x) 57#endif 58 59/* 60 * modpost check for section mismatches during the kernel build. 61 * A section mismatch happens when there are references from a 62 * code or data section to an init section (both code or data). 63 * The init sections are (for most archs) discarded by the kernel 64 * when early init has completed so all such references are potential bugs. 65 * For exit sections the same issue exists. 66 * 67 * The following markers are used for the cases where the reference to 68 * the *init / *exit section (code or data) is valid and will teach 69 * modpost not to issue a warning. Intended semantics is that a code or 70 * data tagged __ref* can reference code or data from init section without 71 * producing a warning (of course, no warning does not mean code is 72 * correct, so optimally document why the __ref is needed and why it's OK). 73 * 74 * The markers follow same syntax rules as __init / __initdata. 75 */ 76#define __ref __section(.ref.text) noinline 77#define __refdata __section(.ref.data) 78#define __refconst __constsection(.ref.rodata) 79 80/* compatibility defines */ 81#define __init_refok __ref 82#define __initdata_refok __refdata 83#define __exit_refok __ref 84 85 86#ifdef MODULE 87#define __exitused 88#else 89#define __exitused __used 90#endif 91 92#define __exit __section(.exit.text) __exitused __cold notrace 93 94/* temporary, until all users are removed */ 95#define __cpuinit 96#define __cpuinitdata 97#define __cpuinitconst 98#define __cpuexit 99#define __cpuexitdata 100#define __cpuexitconst 101 102/* Used for MEMORY_HOTPLUG */ 103#define __meminit __section(.meminit.text) __cold notrace 104#define __meminitdata __section(.meminit.data) 105#define __meminitconst __constsection(.meminit.rodata) 106#define __memexit __section(.memexit.text) __exitused __cold notrace 107#define __memexitdata __section(.memexit.data) 108#define __memexitconst __constsection(.memexit.rodata) 109 110/* For assembly routines */ 111#define __HEAD .section ".head.text","ax" 112#define __INIT .section ".init.text","ax" 113#define __FINIT .previous 114 115#define __INITDATA .section ".init.data","aw",%progbits 116#define __INITRODATA .section ".init.rodata","a",%progbits 117#define __FINITDATA .previous 118 119/* temporary, until all users are removed */ 120#define __CPUINIT 121 122#define __MEMINIT .section ".meminit.text", "ax" 123#define __MEMINITDATA .section ".meminit.data", "aw" 124#define __MEMINITRODATA .section ".meminit.rodata", "a" 125 126/* silence warnings when references are OK */ 127#define __REF .section ".ref.text", "ax" 128#define __REFDATA .section ".ref.data", "aw" 129#define __REFCONST .section ".ref.rodata", "a" 130 131#ifndef __ASSEMBLY__ 132/* 133 * Used for initialization calls.. 134 */ 135typedef int (*initcall_t)(void); 136typedef void (*exitcall_t)(void); 137 138extern initcall_t __con_initcall_start[], __con_initcall_end[]; 139extern initcall_t __security_initcall_start[], __security_initcall_end[]; 140 141/* Used for contructor calls. */ 142typedef void (*ctor_fn_t)(void); 143 144/* Defined in init/main.c */ 145extern int do_one_initcall(initcall_t fn); 146extern char __initdata boot_command_line[]; 147extern char *saved_command_line; 148extern unsigned int reset_devices; 149 150/* used by init/main.c */ 151void setup_arch(char **); 152void prepare_namespace(void); 153void __init load_default_modules(void); 154int __init init_rootfs(void); 155 156extern void (*late_time_init)(void); 157 158extern bool initcall_debug; 159 160#endif 161 162#ifndef MODULE 163 164#ifndef __ASSEMBLY__ 165 166#ifdef CONFIG_LTO 167/* Work around a LTO gcc problem: when there is no reference to a variable 168 * in a module it will be moved to the end of the program. This causes 169 * reordering of initcalls which the kernel does not like. 170 * Add a dummy reference function to avoid this. The function is 171 * deleted by the linker. 172 */ 173#define LTO_REFERENCE_INITCALL(x) \ 174 ; /* yes this is needed */ \ 175 static __used __exit void *reference_##x(void) \ 176 { \ 177 return &x; \ 178 } 179#else 180#define LTO_REFERENCE_INITCALL(x) 181#endif 182 183/* initcalls are now grouped by functionality into separate 184 * subsections. Ordering inside the subsections is determined 185 * by link order. 186 * For backwards compatibility, initcall() puts the call in 187 * the device init subsection. 188 * 189 * The `id' arg to __define_initcall() is needed so that multiple initcalls 190 * can point at the same handler without causing duplicate-symbol build errors. 191 */ 192 193#define __define_initcall(fn, id) \ 194 static initcall_t __initcall_##fn##id __used \ 195 __attribute__((__section__(".initcall" #id ".init"))) = fn; \ 196 LTO_REFERENCE_INITCALL(__initcall_##fn##id) 197 198/* 199 * Early initcalls run before initializing SMP. 200 * 201 * Only for built-in code, not modules. 202 */ 203#define early_initcall(fn) __define_initcall(fn, early) 204 205/* 206 * A "pure" initcall has no dependencies on anything else, and purely 207 * initializes variables that couldn't be statically initialized. 208 * 209 * This only exists for built-in code, not for modules. 210 * Keep main.c:initcall_level_names[] in sync. 211 */ 212#define pure_initcall(fn) __define_initcall(fn, 0) 213 214#define core_initcall(fn) __define_initcall(fn, 1) 215#define core_initcall_sync(fn) __define_initcall(fn, 1s) 216#define postcore_initcall(fn) __define_initcall(fn, 2) 217#define postcore_initcall_sync(fn) __define_initcall(fn, 2s) 218#define arch_initcall(fn) __define_initcall(fn, 3) 219#define arch_initcall_sync(fn) __define_initcall(fn, 3s) 220#define subsys_initcall(fn) __define_initcall(fn, 4) 221#define subsys_initcall_sync(fn) __define_initcall(fn, 4s) 222#define fs_initcall(fn) __define_initcall(fn, 5) 223#define fs_initcall_sync(fn) __define_initcall(fn, 5s) 224#define rootfs_initcall(fn) __define_initcall(fn, rootfs) 225#define device_initcall(fn) __define_initcall(fn, 6) 226#define device_initcall_sync(fn) __define_initcall(fn, 6s) 227#define late_initcall(fn) __define_initcall(fn, 7) 228#define late_initcall_sync(fn) __define_initcall(fn, 7s) 229 230#define __initcall(fn) device_initcall(fn) 231 232#define __exitcall(fn) \ 233 static exitcall_t __exitcall_##fn __exit_call = fn 234 235#define console_initcall(fn) \ 236 static initcall_t __initcall_##fn \ 237 __used __section(.con_initcall.init) = fn 238 239#define security_initcall(fn) \ 240 static initcall_t __initcall_##fn \ 241 __used __section(.security_initcall.init) = fn 242 243struct obs_kernel_param { 244 const char *str; 245 int (*setup_func)(char *); 246 int early; 247}; 248 249/* 250 * Only for really core code. See moduleparam.h for the normal way. 251 * 252 * Force the alignment so the compiler doesn't space elements of the 253 * obs_kernel_param "array" too far apart in .init.setup. 254 */ 255#define __setup_param(str, unique_id, fn, early) \ 256 static const char __setup_str_##unique_id[] __initconst \ 257 __aligned(1) = str; \ 258 static struct obs_kernel_param __setup_##unique_id \ 259 __used __section(.init.setup) \ 260 __attribute__((aligned((sizeof(long))))) \ 261 = { __setup_str_##unique_id, fn, early } 262 263#define __setup(str, fn) \ 264 __setup_param(str, fn, fn, 0) 265 266/* NOTE: fn is as per module_param, not __setup! Emits warning if fn 267 * returns non-zero. */ 268#define early_param(str, fn) \ 269 __setup_param(str, fn, fn, 1) 270 271/* Relies on boot_command_line being set */ 272void __init parse_early_param(void); 273void __init parse_early_options(char *cmdline); 274#endif /* __ASSEMBLY__ */ 275 276/** 277 * module_init() - driver initialization entry point 278 * @x: function to be run at kernel boot time or module insertion 279 * 280 * module_init() will either be called during do_initcalls() (if 281 * builtin) or at module insertion time (if a module). There can only 282 * be one per module. 283 */ 284#define module_init(x) __initcall(x); 285 286/** 287 * module_exit() - driver exit entry point 288 * @x: function to be run when driver is removed 289 * 290 * module_exit() will wrap the driver clean-up code 291 * with cleanup_module() when used with rmmod when 292 * the driver is a module. If the driver is statically 293 * compiled into the kernel, module_exit() has no effect. 294 * There can only be one per module. 295 */ 296#define module_exit(x) __exitcall(x); 297 298#else /* MODULE */ 299 300/* 301 * In most cases loadable modules do not need custom 302 * initcall levels. There are still some valid cases where 303 * a driver may be needed early if built in, and does not 304 * matter when built as a loadable module. Like bus 305 * snooping debug drivers. 306 */ 307#define early_initcall(fn) module_init(fn) 308#define core_initcall(fn) module_init(fn) 309#define core_initcall_sync(fn) module_init(fn) 310#define postcore_initcall(fn) module_init(fn) 311#define postcore_initcall_sync(fn) module_init(fn) 312#define arch_initcall(fn) module_init(fn) 313#define subsys_initcall(fn) module_init(fn) 314#define subsys_initcall_sync(fn) module_init(fn) 315#define fs_initcall(fn) module_init(fn) 316#define fs_initcall_sync(fn) module_init(fn) 317#define rootfs_initcall(fn) module_init(fn) 318#define device_initcall(fn) module_init(fn) 319#define device_initcall_sync(fn) module_init(fn) 320#define late_initcall(fn) module_init(fn) 321#define late_initcall_sync(fn) module_init(fn) 322 323#define console_initcall(fn) module_init(fn) 324#define security_initcall(fn) module_init(fn) 325 326/* Each module must use one module_init(). */ 327#define module_init(initfn) \ 328 static inline initcall_t __inittest(void) \ 329 { return initfn; } \ 330 int init_module(void) __attribute__((alias(#initfn))); 331 332/* This is only required if you want to be unloadable. */ 333#define module_exit(exitfn) \ 334 static inline exitcall_t __exittest(void) \ 335 { return exitfn; } \ 336 void cleanup_module(void) __attribute__((alias(#exitfn))); 337 338#define __setup_param(str, unique_id, fn) /* nothing */ 339#define __setup(str, func) /* nothing */ 340#endif 341 342/* Data marked not to be saved by software suspend */ 343#define __nosavedata __section(.data..nosave) 344 345/* This means "can be init if no module support, otherwise module load 346 may call it." */ 347#ifdef CONFIG_MODULES 348#define __init_or_module 349#define __initdata_or_module 350#define __initconst_or_module 351#define __INIT_OR_MODULE .text 352#define __INITDATA_OR_MODULE .data 353#define __INITRODATA_OR_MODULE .section ".rodata","a",%progbits 354#else 355#define __init_or_module __init 356#define __initdata_or_module __initdata 357#define __initconst_or_module __initconst 358#define __INIT_OR_MODULE __INIT 359#define __INITDATA_OR_MODULE __INITDATA 360#define __INITRODATA_OR_MODULE __INITRODATA 361#endif /*CONFIG_MODULES*/ 362 363#ifdef MODULE 364#define __exit_p(x) x 365#else 366#define __exit_p(x) NULL 367#endif 368 369#endif /* _LINUX_INIT_H */ 370