include/linux/module.h

   1 #ifndef _LINUX_MODULE_H
   2 #define _LINUX_MODULE_H
   3 /*
   4  * Dynamic loading of modules into the kernel.
   5  *
   6  * Rewritten by Richard Henderson <rth@tamu.edu> Dec 1996
   7  * Rewritten again by Rusty Russell, 2002
   8  */
   9 #include <linux/config.h>
  10 #include <linux/sched.h>
  11 #include <linux/spinlock.h>
  12 #include <linux/list.h>
  13 #include <linux/stat.h>
  14 #include <linux/compiler.h>
  15 #include <linux/cache.h>
  16 #include <linux/kmod.h>
  17 #include <linux/elf.h>
  18 #include <linux/stringify.h>
  19 #include <asm/local.h>
  20
  21 #include <asm/module.h>
  22
  23 /* Not Yet Implemented */
  24 #define MODULE_SUPPORTED_DEVICE(name)
  25 #define print_modules()
  26
  27 /* v850 toolchain uses a `_' prefix for all user symbols */
  28 #ifndef MODULE_SYMBOL_PREFIX
  29 #define MODULE_SYMBOL_PREFIX ""
  30 #endif
  31
  32 #define MODULE_NAME_LEN (64 - sizeof(unsigned long))
  33
  34 struct kernel_symbol
  35 {
  36         unsigned long value;
  37         const char *name;
  38 };
  39
  40 struct modversion_info
  41 {
  42         unsigned long crc;
  43         char name[MODULE_NAME_LEN];
  44 };
  45
  46 /* These are either module local, or the kernel's dummy ones. */
  47 extern int init_module(void);
  48 extern void cleanup_module(void);
  49
  50 /* Archs provide a method of finding the correct exception table. */
  51 struct exception_table_entry;
  52
  53 const struct exception_table_entry *
  54 search_extable(const struct exception_table_entry *first,
  55                const struct exception_table_entry *last,
  56                unsigned long value);
  57 void sort_extable(struct exception_table_entry *start,
  58                   struct exception_table_entry *finish);
  59 void sort_main_extable(void);
  60
  61 #ifdef MODULE
  62 #define ___module_cat(a,b) __mod_ ## a ## b
  63 #define __module_cat(a,b) ___module_cat(a,b)
  64 #define __MODULE_INFO(tag, name, info)                                    \
  65 static const char __module_cat(name,__LINE__)[]                           \
  66   __attribute_used__                                                      \
  67   __attribute__((section(".modinfo"),unused)) = __stringify(tag) "=" info
  68
  69 #define MODULE_GENERIC_TABLE(gtype,name)                        \
  70 extern const struct gtype##_id __mod_##gtype##_table            \
  71   __attribute__ ((unused, alias(__stringify(name))))
  72
  73 extern struct module __this_module;
  74 #define THIS_MODULE (&__this_module)
  75
  76 #else  /* !MODULE */
  77
  78 #define MODULE_GENERIC_TABLE(gtype,name)
  79 #define __MODULE_INFO(tag, name, info)
  80 #define THIS_MODULE ((struct module *)0)
  81 #endif
  82
  83 /* Generic info of form tag = "info" */
  84 #define MODULE_INFO(tag, info) __MODULE_INFO(tag, tag, info)
  85
  86 /* For userspace: you can also call me... */
  87 #define MODULE_ALIAS(_alias) MODULE_INFO(alias, _alias)
  88
  89 /*
  90  * The following license idents are currently accepted as indicating free
  91  * software modules
  92  *
  93  *      "GPL"                           [GNU Public License v2 or later]
  94  *      "GPL v2"                        [GNU Public License v2]
  95  *      "GPL and additional rights"     [GNU Public License v2 rights and more]
  96  *      "Dual BSD/GPL"                  [GNU Public License v2
  97  *                                       or BSD license choice]
  98  *      "Dual MPL/GPL"                  [GNU Public License v2
  99  *                                       or Mozilla license choice]
 100  *
 101  * The following other idents are available
 102  *
 103  *      "Proprietary"                   [Non free products]
 104  *
 105  * There are dual licensed components, but when running with Linux it is the
 106  * GPL that is relevant so this is a non issue. Similarly LGPL linked with GPL
 107  * is a GPL combined work.
 108  *
 109  * This exists for several reasons
 110  * 1.   So modinfo can show license info for users wanting to vet their setup
 111  *      is free
 112  * 2.   So the community can ignore bug reports including proprietary modules
 113  * 3.   So vendors can do likewise based on their own policies
 114  */
 115 #define MODULE_LICENSE(_license) MODULE_INFO(license, _license)
 116
 117 /* Author, ideally of form NAME <EMAIL>[, NAME <EMAIL>]*[ and NAME <EMAIL>] */
 118 #define MODULE_AUTHOR(_author) MODULE_INFO(author, _author)
 119
 120 /* What your module does. */
 121 #define MODULE_DESCRIPTION(_description) MODULE_INFO(description, _description)
 122
 123 /* One for each parameter, describing how to use it.  Some files do
 124    multiple of these per line, so can't just use MODULE_INFO. */
 125 #define MODULE_PARM_DESC(_parm, desc) \
 126         __MODULE_INFO(parm, _parm, #_parm ":" desc)
 127
 128 #define MODULE_DEVICE_TABLE(type,name)          \
 129   MODULE_GENERIC_TABLE(type##_device,name)
 130
 131 /* Version of form [<epoch>:]<version>[-<extra-version>].
 132    Or for CVS/RCS ID version, everything but the number is stripped.
 133   <epoch>: A (small) unsigned integer which allows you to start versions
 134            anew. If not mentioned, it's zero.  eg. "2:1.0" is after
 135            "1:2.0".
 136   <version>: The <version> may contain only alphanumerics and the
 137            character `.'.  Ordered by numeric sort for numeric parts,
 138            ascii sort for ascii parts (as per RPM or DEB algorithm).
 139   <extraversion>: Like <version>, but inserted for local
 140            customizations, eg "rh3" or "rusty1".
 141
 142   Using this automatically adds a checksum of the .c files and the
 143   local headers to the end.  Use MODULE_VERSION("") if you want just
 144   this.  Macro includes room for this.
 145 */
 146 #define MODULE_VERSION(_version) \
 147   MODULE_INFO(version, _version "\0xxxxxxxxxxxxxxxxxxxxxxxx")
 148
 149 /* Given an address, look for it in the exception tables */
 150 const struct exception_table_entry *search_exception_tables(unsigned long add);
 151
 152 struct notifier_block;
 153
 154 #ifdef CONFIG_MODULES
 155
 156 /* Get/put a kernel symbol (calls must be symmetric) */
 157 void *__symbol_get(const char *symbol);
 158 void *__symbol_get_gpl(const char *symbol);
 159 #define symbol_get(x) ((typeof(&x))(__symbol_get(MODULE_SYMBOL_PREFIX #x)))
 160
 161 #ifndef __GENKSYMS__
 162 #ifdef CONFIG_MODVERSIONS
 163 /* Mark the CRC weak since genksyms apparently decides not to
 164  * generate a checksums for some symbols */
 165 #define __CRC_SYMBOL(sym, sec)                                  \
 166         extern void *__crc_##sym __attribute__((weak));         \
 167         static const unsigned long __kcrctab_##sym              \
 168         __attribute_used__                                      \
 169         __attribute__((section("__kcrctab" sec), unused))       \
 170         = (unsigned long) &__crc_##sym;
 171 #else
 172 #define __CRC_SYMBOL(sym, sec)
 173 #endif
 174
 175 /* For every exported symbol, place a struct in the __ksymtab section */
 176 #define __EXPORT_SYMBOL(sym, sec)                               \
 177         __CRC_SYMBOL(sym, sec)                                  \
 178         static const char __kstrtab_##sym[]                     \
 179         __attribute__((section("__ksymtab_strings")))           \
 180         = MODULE_SYMBOL_PREFIX #sym;                            \
 181         static const struct kernel_symbol __ksymtab_##sym       \
 182         __attribute_used__                                      \
 183         __attribute__((section("__ksymtab" sec), unused))       \
 184         = { (unsigned long)&sym, __kstrtab_##sym }
 185
 186 #define EXPORT_SYMBOL(sym)                                      \
 187         __EXPORT_SYMBOL(sym, "")
 188
 189 #define EXPORT_SYMBOL_GPL(sym)                                  \
 190         __EXPORT_SYMBOL(sym, "_gpl")
 191
 192 #endif
 193
 194 /* We don't mangle the actual symbol anymore, so no need for
 195  * special casing EXPORT_SYMBOL_NOVERS.  FIXME: Deprecated */
 196 #define EXPORT_SYMBOL_NOVERS(sym) EXPORT_SYMBOL(sym)
 197
 198 struct module_ref
 199 {
 200         local_t count;
 201 } ____cacheline_aligned;
 202
 203 enum module_state
 204 {
 205         MODULE_STATE_LIVE,
 206         MODULE_STATE_COMING,
 207         MODULE_STATE_GOING,
 208 };
 209
 210 struct module
 211 {
 212         enum module_state state;
 213
 214         /* Member of list of modules */
 215         struct list_head list;
 216
 217         /* Unique handle for this module */
 218         char name[MODULE_NAME_LEN];
 219
 220         /* Exported symbols */
 221         const struct kernel_symbol *syms;
 222         unsigned int num_syms;
 223         const unsigned long *crcs;
 224
 225         /* GPL-only exported symbols. */
 226         const struct kernel_symbol *gpl_syms;
 227         unsigned int num_gpl_syms;
 228         const unsigned long *gpl_crcs;
 229
 230         /* Exception table */
 231         unsigned int num_exentries;
 232         const struct exception_table_entry *extable;
 233
 234         /* Startup function. */
 235         int (*init)(void);
 236
 237         /* If this is non-NULL, vfree after init() returns */
 238         void *module_init;
 239
 240         /* Here is the actual code + data, vfree'd on unload. */
 241         void *module_core;
 242
 243         /* Here are the sizes of the init and core sections */
 244         unsigned long init_size, core_size;
 245
 246         /* The size of the executable code in each section.  */
 247         unsigned long init_text_size, core_text_size;
 248
 249         /* Arch-specific module values */
 250         struct mod_arch_specific arch;
 251
 252         /* Am I unsafe to unload? */
 253         int unsafe;
 254
 255         /* Am I GPL-compatible */
 256         int license_gplok;
 257
 258 #ifdef CONFIG_MODULE_UNLOAD
 259         /* Reference counts */
 260         struct module_ref ref[NR_CPUS];
 261
 262         /* What modules depend on me? */
 263         struct list_head modules_which_use_me;
 264
 265         /* Who is waiting for us to be unloaded */
 266         struct task_struct *waiter;
 267
 268         /* Destruction function. */
 269         void (*exit)(void);
 270 #endif
 271
 272 #ifdef CONFIG_KALLSYMS
 273         /* We keep the symbol and string tables for kallsyms. */
 274         Elf_Sym *symtab;
 275         unsigned long num_symtab;
 276         char *strtab;
 277 #endif
 278
 279         /* Per-cpu data. */
 280         void *percpu;
 281
 282         /* The command line arguments (may be mangled).  People like
 283            keeping pointers to this stuff */
 284         char *args;
 285 };
 286
 287 /* FIXME: It'd be nice to isolate modules during init, too, so they
 288    aren't used before they (may) fail.  But presently too much code
 289    (IDE & SCSI) require entry into the module during init.*/
 290 static inline int module_is_live(struct module *mod)
 291 {
 292         return mod->state != MODULE_STATE_GOING;
 293 }
 294
 295 /* Is this address in a module? */
 296 struct module *module_text_address(unsigned long addr);
 297
 298 /* Returns module and fills in value, defined and namebuf, or NULL if
 299    symnum out of range. */
 300 struct module *module_get_kallsym(unsigned int symnum,
 301                                   unsigned long *value,
 302                                   char *type,
 303                                   char namebuf[128]);
 304
 305 /* Look for this name: can be of form module:name. */
 306 unsigned long module_kallsyms_lookup_name(const char *name);
 307
 308 int is_exported(const char *name, const struct module *mod);
 309
 310 extern void __module_put_and_exit(struct module *mod, long code)
 311         __attribute__((noreturn));
 312 #define module_put_and_exit(code) __module_put_and_exit(THIS_MODULE, code);
 313
 314 #ifdef CONFIG_MODULE_UNLOAD
 315 unsigned int module_refcount(struct module *mod);
 316 void __symbol_put(const char *symbol);
 317 #define symbol_put(x) __symbol_put(MODULE_SYMBOL_PREFIX #x)
 318 void symbol_put_addr(void *addr);
 319
 320 /* Sometimes we know we already have a refcount, and it's easier not
 321    to handle the error case (which only happens with rmmod --wait). */
 322 static inline void __module_get(struct module *module)
 323 {
 324         if (module) {
 325                 BUG_ON(module_refcount(module) == 0);
 326                 local_inc(&module->ref[get_cpu()].count);
 327                 put_cpu();
 328         }
 329 }
 330
 331 static inline int try_module_get(struct module *module)
 332 {
 333         int ret = 1;
 334
 335         if (module) {
 336                 unsigned int cpu = get_cpu();
 337                 if (likely(module_is_live(module)))
 338                         local_inc(&module->ref[cpu].count);
 339                 else
 340                         ret = 0;
 341                 put_cpu();
 342         }
 343         return ret;
 344 }
 345
 346 static inline void module_put(struct module *module)
 347 {
 348         if (module) {
 349                 unsigned int cpu = get_cpu();
 350                 local_dec(&module->ref[cpu].count);
 351                 /* Maybe they're waiting for us to drop reference? */
 352                 if (unlikely(!module_is_live(module)))
 353                         wake_up_process(module->waiter);
 354                 put_cpu();
 355         }
 356 }
 357
 358 #else /*!CONFIG_MODULE_UNLOAD*/
 359 static inline int try_module_get(struct module *module)
 360 {
 361         return !module || module_is_live(module);
 362 }
 363 static inline void module_put(struct module *module)
 364 {
 365 }
 366 static inline void __module_get(struct module *module)
 367 {
 368 }
 369 #define symbol_put(x) do { } while(0)
 370 #define symbol_put_addr(p) do { } while(0)
 371
 372 #endif /* CONFIG_MODULE_UNLOAD */
 373
 374 /* This is a #define so the string doesn't get put in every .o file */
 375 #define module_name(mod)                        \
 376 ({                                              \
 377         struct module *__mod = (mod);           \
 378         __mod ? __mod->name : "kernel";         \
 379 })
 380
 381 #define __unsafe(mod)                                                        \
 382 do {                                                                         \
 383         if (mod && !(mod)->unsafe) {                                         \
 384                 printk(KERN_WARNING                                          \
 385                        "Module %s cannot be unloaded due to unsafe usage in" \
 386                        " %s:%u\n", (mod)->name, __FILE__, __LINE__);         \
 387                 (mod)->unsafe = 1;                                           \
 388         }                                                                    \
 389 } while(0)
 390
 391 /* For kallsyms to ask for address resolution.  NULL means not found. */
 392 const char *module_address_lookup(unsigned long addr,
 393                                   unsigned long *symbolsize,
 394                                   unsigned long *offset,
 395                                   char **modname);
 396
 397 /* For extable.c to search modules' exception tables. */
 398 const struct exception_table_entry *search_module_extables(unsigned long addr);
 399
 400 int register_module_notifier(struct notifier_block * nb);
 401 int unregister_module_notifier(struct notifier_block * nb);
 402
 403 #else /* !CONFIG_MODULES... */
 404 #define EXPORT_SYMBOL(sym)
 405 #define EXPORT_SYMBOL_GPL(sym)
 406 #define EXPORT_SYMBOL_NOVERS(sym)
 407
 408 /* Given an address, look for it in the exception tables. */
 409 static inline const struct exception_table_entry *
 410 search_module_extables(unsigned long addr)
 411 {
 412         return NULL;
 413 }
 414
 415 /* Is this address in a module? */
 416 static inline struct module *module_text_address(unsigned long addr)
 417 {
 418         return NULL;
 419 }
 420
 421 /* Get/put a kernel symbol (calls should be symmetric) */
 422 #define symbol_get(x) ({ extern typeof(x) x __attribute__((weak)); &(x); })
 423 #define symbol_put(x) do { } while(0)
 424 #define symbol_put_addr(x) do { } while(0)
 425
 426 static inline void __module_get(struct module *module)
 427 {
 428 }
 429
 430 static inline int try_module_get(struct module *module)
 431 {
 432         return 1;
 433 }
 434
 435 static inline void module_put(struct module *module)
 436 {
 437 }
 438
 439 #define module_name(mod) "kernel"
 440
 441 #define __unsafe(mod)
 442
 443 /* For kallsyms to ask for address resolution.  NULL means not found. */
 444 static inline const char *module_address_lookup(unsigned long addr,
 445                                                 unsigned long *symbolsize,
 446                                                 unsigned long *offset,
 447                                                 char **modname)
 448 {
 449         return NULL;
 450 }
 451
 452 static inline struct module *module_get_kallsym(unsigned int symnum,
 453                                                 unsigned long *value,
 454                                                 char *type,
 455                                                 char namebuf[128])
 456 {
 457         return NULL;
 458 }
 459
 460 static inline unsigned long module_kallsyms_lookup_name(const char *name)
 461 {
 462         return 0;
 463 }
 464
 465 static inline int is_exported(const char *name, const struct module *mod)
 466 {
 467         return 0;
 468 }
 469
 470 static inline int register_module_notifier(struct notifier_block * nb)
 471 {
 472         /* no events will happen anyway, so this can always succeed */
 473         return 0;
 474 }
 475
 476 static inline int unregister_module_notifier(struct notifier_block * nb)
 477 {
 478         return 0;
 479 }
 480
 481 #define module_put_and_exit(code) do_exit(code)
 482
 483 #endif /* CONFIG_MODULES */
 484
 485 #define symbol_request(x) try_then_request_module(symbol_get(x), "symbol:" #x)
 486
 487 /* BELOW HERE ALL THESE ARE OBSOLETE AND WILL VANISH */
 488
 489 struct obsolete_modparm {
 490         char name[64];
 491         char type[64-sizeof(void *)];
 492         void *addr;
 493 };
 494 #ifdef MODULE
 495 /* DEPRECATED: Do not use. */
 496 #define MODULE_PARM(var,type)                                               \
 497 struct obsolete_modparm __parm_##var __attribute__((section("__obsparm"))) = \
 498 { __stringify(var), type };
 499
 500 static inline void __deprecated MOD_INC_USE_COUNT(struct module *module)
 501 {
 502         __unsafe(module);
 503
 504 #if defined(CONFIG_MODULE_UNLOAD) && defined(MODULE)
 505         local_inc(&module->ref[get_cpu()].count);
 506         put_cpu();
 507 #else
 508         (void)try_module_get(module);
 509 #endif
 510 }
 511
 512 static inline void __deprecated MOD_DEC_USE_COUNT(struct module *module)
 513 {
 514         module_put(module);
 515 }
 516
 517 #define MOD_INC_USE_COUNT       MOD_INC_USE_COUNT(THIS_MODULE)
 518 #define MOD_DEC_USE_COUNT       MOD_DEC_USE_COUNT(THIS_MODULE)
 519 #else
 520 #define MODULE_PARM(var,type)
 521 #define MOD_INC_USE_COUNT       do { } while (0)
 522 #define MOD_DEC_USE_COUNT       do { } while (0)
 523 #endif
 524
 525 #define __MODULE_STRING(x) __stringify(x)
 526
 527 /* Use symbol_get and symbol_put instead.  You'll thank me. */
 528 #define HAVE_INTER_MODULE
 529 extern void inter_module_register(const char *, struct module *, const void *);
 530 extern void inter_module_unregister(const char *);
 531 extern const void *inter_module_get(const char *);
 532 extern const void *inter_module_get_request(const char *, const char *);
 533 extern void inter_module_put(const char *);
 534
 535 #endif /* _LINUX_MODULE_H */