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/sched.h>
  10 #include <linux/spinlock.h>
  11 #include <linux/list.h>
  12 #include <linux/stat.h>
  13 #include <linux/compiler.h>
  14 #include <linux/cache.h>
  15 #include <linux/kmod.h>
  16 #include <linux/elf.h>
  17 #include <linux/stringify.h>
  18 #include <linux/kobject.h>
  19 #include <linux/moduleparam.h>
  20 #include <asm/local.h>
  21
  22 #include <asm/module.h>
  23
  24 /* Not Yet Implemented */
  25 #define MODULE_SUPPORTED_DEVICE(name)
  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 struct module;
  47
  48 struct module_attribute {
  49         struct attribute attr;
  50         ssize_t (*show)(struct module_attribute *, struct module *, char *);
  51         ssize_t (*store)(struct module_attribute *, struct module *,
  52                          const char *, size_t count);
  53         void (*setup)(struct module *, const char *);
  54         int (*test)(struct module *);
  55         void (*free)(struct module *);
  56 };
  57
  58 struct module_kobject
  59 {
  60         struct kobject kobj;
  61         struct module *mod;
  62 };
  63
  64 /* These are either module local, or the kernel's dummy ones. */
  65 extern int init_module(void);
  66 extern void cleanup_module(void);
  67
  68 /* Archs provide a method of finding the correct exception table. */
  69 struct exception_table_entry;
  70
  71 const struct exception_table_entry *
  72 search_extable(const struct exception_table_entry *first,
  73                const struct exception_table_entry *last,
  74                unsigned long value);
  75 void sort_extable(struct exception_table_entry *start,
  76                   struct exception_table_entry *finish);
  77 void sort_main_extable(void);
  78
  79 extern struct subsystem module_subsys;
  80
  81 #ifdef MODULE
  82 #define MODULE_GENERIC_TABLE(gtype,name)                        \
  83 extern const struct gtype##_id __mod_##gtype##_table            \
  84   __attribute__ ((unused, alias(__stringify(name))))
  85
  86 extern struct module __this_module;
  87 #define THIS_MODULE (&__this_module)
  88 #else  /* !MODULE */
  89 #define MODULE_GENERIC_TABLE(gtype,name)
  90 #define THIS_MODULE ((struct module *)0)
  91 #endif
  92
  93 /* Generic info of form tag = "info" */
  94 #define MODULE_INFO(tag, info) __MODULE_INFO(tag, tag, info)
  95
  96 /* For userspace: you can also call me... */
  97 #define MODULE_ALIAS(_alias) MODULE_INFO(alias, _alias)
  98
  99 /*
 100  * The following license idents are currently accepted as indicating free
 101  * software modules
 102  *
 103  *      "GPL"                           [GNU Public License v2 or later]
 104  *      "GPL v2"                        [GNU Public License v2]
 105  *      "GPL and additional rights"     [GNU Public License v2 rights and more]
 106  *      "Dual BSD/GPL"                  [GNU Public License v2
 107  *                                       or BSD license choice]
 108  *      "Dual MIT/GPL"                  [GNU Public License v2
 109  *                                       or MIT license choice]
 110  *      "Dual MPL/GPL"                  [GNU Public License v2
 111  *                                       or Mozilla license choice]
 112  *
 113  * The following other idents are available
 114  *
 115  *      "Proprietary"                   [Non free products]
 116  *
 117  * There are dual licensed components, but when running with Linux it is the
 118  * GPL that is relevant so this is a non issue. Similarly LGPL linked with GPL
 119  * is a GPL combined work.
 120  *
 121  * This exists for several reasons
 122  * 1.   So modinfo can show license info for users wanting to vet their setup
 123  *      is free
 124  * 2.   So the community can ignore bug reports including proprietary modules
 125  * 3.   So vendors can do likewise based on their own policies
 126  */
 127 #define MODULE_LICENSE(_license) MODULE_INFO(license, _license)
 128
 129 /* Author, ideally of form NAME <EMAIL>[, NAME <EMAIL>]*[ and NAME <EMAIL>] */
 130 #define MODULE_AUTHOR(_author) MODULE_INFO(author, _author)
 131
 132 /* What your module does. */
 133 #define MODULE_DESCRIPTION(_description) MODULE_INFO(description, _description)
 134
 135 /* One for each parameter, describing how to use it.  Some files do
 136    multiple of these per line, so can't just use MODULE_INFO. */
 137 #define MODULE_PARM_DESC(_parm, desc) \
 138         __MODULE_INFO(parm, _parm, #_parm ":" desc)
 139
 140 #define MODULE_DEVICE_TABLE(type,name)          \
 141   MODULE_GENERIC_TABLE(type##_device,name)
 142
 143 /* Version of form [<epoch>:]<version>[-<extra-version>].
 144    Or for CVS/RCS ID version, everything but the number is stripped.
 145   <epoch>: A (small) unsigned integer which allows you to start versions
 146            anew. If not mentioned, it's zero.  eg. "2:1.0" is after
 147            "1:2.0".
 148   <version>: The <version> may contain only alphanumerics and the
 149            character `.'.  Ordered by numeric sort for numeric parts,
 150            ascii sort for ascii parts (as per RPM or DEB algorithm).
 151   <extraversion>: Like <version>, but inserted for local
 152            customizations, eg "rh3" or "rusty1".
 153
 154   Using this automatically adds a checksum of the .c files and the
 155   local headers in "srcversion".
 156 */
 157 #define MODULE_VERSION(_version) MODULE_INFO(version, _version)
 158
 159 /* Optional firmware file (or files) needed by the module
 160  * format is simply firmware file name.  Multiple firmware
 161  * files require multiple MODULE_FIRMWARE() specifiers */
 162 #define MODULE_FIRMWARE(_firmware) MODULE_INFO(firmware, _firmware)
 163
 164 /* Given an address, look for it in the exception tables */
 165 const struct exception_table_entry *search_exception_tables(unsigned long add);
 166
 167 struct notifier_block;
 168
 169 #ifdef CONFIG_MODULES
 170
 171 /* Get/put a kernel symbol (calls must be symmetric) */
 172 void *__symbol_get(const char *symbol);
 173 void *__symbol_get_gpl(const char *symbol);
 174 #define symbol_get(x) ((typeof(&x))(__symbol_get(MODULE_SYMBOL_PREFIX #x)))
 175
 176 #ifndef __GENKSYMS__
 177 #ifdef CONFIG_MODVERSIONS
 178 /* Mark the CRC weak since genksyms apparently decides not to
 179  * generate a checksums for some symbols */
 180 #define __CRC_SYMBOL(sym, sec)                                  \
 181         extern void *__crc_##sym __attribute__((weak));         \
 182         static const unsigned long __kcrctab_##sym              \
 183         __attribute_used__                                      \
 184         __attribute__((section("__kcrctab" sec), unused))       \
 185         = (unsigned long) &__crc_##sym;
 186 #else
 187 #define __CRC_SYMBOL(sym, sec)
 188 #endif
 189
 190 /* For every exported symbol, place a struct in the __ksymtab section */
 191 #define __EXPORT_SYMBOL(sym, sec)                               \
 192         extern typeof(sym) sym;                                 \
 193         __CRC_SYMBOL(sym, sec)                                  \
 194         static const char __kstrtab_##sym[]                     \
 195         __attribute__((section("__ksymtab_strings")))           \
 196         = MODULE_SYMBOL_PREFIX #sym;                            \
 197         static const struct kernel_symbol __ksymtab_##sym       \
 198         __attribute_used__                                      \
 199         __attribute__((section("__ksymtab" sec), unused))       \
 200         = { (unsigned long)&sym, __kstrtab_##sym }
 201
 202 #define EXPORT_SYMBOL(sym)                                      \
 203         __EXPORT_SYMBOL(sym, "")
 204
 205 #define EXPORT_SYMBOL_GPL(sym)                                  \
 206         __EXPORT_SYMBOL(sym, "_gpl")
 207
 208 #define EXPORT_SYMBOL_GPL_FUTURE(sym)                           \
 209         __EXPORT_SYMBOL(sym, "_gpl_future")
 210
 211
 212 #ifdef CONFIG_UNUSED_SYMBOLS
 213 #define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused")
 214 #define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl")
 215 #else
 216 #define EXPORT_UNUSED_SYMBOL(sym)
 217 #define EXPORT_UNUSED_SYMBOL_GPL(sym)
 218 #endif
 219
 220 #endif
 221
 222 struct module_ref
 223 {
 224         local_t count;
 225 } ____cacheline_aligned;
 226
 227 enum module_state
 228 {
 229         MODULE_STATE_LIVE,
 230         MODULE_STATE_COMING,
 231         MODULE_STATE_GOING,
 232 };
 233
 234 /* Similar stuff for section attributes. */
 235 struct module_sect_attr
 236 {
 237         struct module_attribute mattr;
 238         char *name;
 239         unsigned long address;
 240 };
 241
 242 struct module_sect_attrs
 243 {
 244         struct attribute_group grp;
 245         int nsections;
 246         struct module_sect_attr attrs[0];
 247 };
 248
 249 struct module_param_attrs;
 250
 251 struct module
 252 {
 253         enum module_state state;
 254
 255         /* Member of list of modules */
 256         struct list_head list;
 257
 258         /* Unique handle for this module */
 259         char name[MODULE_NAME_LEN];
 260
 261         /* Sysfs stuff. */
 262         struct module_kobject mkobj;
 263         struct module_param_attrs *param_attrs;
 264         struct module_attribute *modinfo_attrs;
 265         const char *version;
 266         const char *srcversion;
 267
 268         /* Exported symbols */
 269         const struct kernel_symbol *syms;
 270         unsigned int num_syms;
 271         const unsigned long *crcs;
 272
 273         /* GPL-only exported symbols. */
 274         const struct kernel_symbol *gpl_syms;
 275         unsigned int num_gpl_syms;
 276         const unsigned long *gpl_crcs;
 277
 278         /* unused exported symbols. */
 279         const struct kernel_symbol *unused_syms;
 280         unsigned int num_unused_syms;
 281         const unsigned long *unused_crcs;
 282         /* GPL-only, unused exported symbols. */
 283         const struct kernel_symbol *unused_gpl_syms;
 284         unsigned int num_unused_gpl_syms;
 285         const unsigned long *unused_gpl_crcs;
 286
 287         /* symbols that will be GPL-only in the near future. */
 288         const struct kernel_symbol *gpl_future_syms;
 289         unsigned int num_gpl_future_syms;
 290         const unsigned long *gpl_future_crcs;
 291
 292         /* Exception table */
 293         unsigned int num_exentries;
 294         const struct exception_table_entry *extable;
 295
 296         /* Startup function. */
 297         int (*init)(void);
 298
 299         /* If this is non-NULL, vfree after init() returns */
 300         void *module_init;
 301
 302         /* Here is the actual code + data, vfree'd on unload. */
 303         void *module_core;
 304
 305         /* Here are the sizes of the init and core sections */
 306         unsigned long init_size, core_size;
 307
 308         /* The size of the executable code in each section.  */
 309         unsigned long init_text_size, core_text_size;
 310
 311         /* The handle returned from unwind_add_table. */
 312         void *unwind_info;
 313
 314         /* Arch-specific module values */
 315         struct mod_arch_specific arch;
 316
 317         /* Am I unsafe to unload? */
 318         int unsafe;
 319
 320         /* Am I GPL-compatible */
 321         int license_gplok;
 322
 323 #ifdef CONFIG_MODULE_UNLOAD
 324         /* Reference counts */
 325         struct module_ref ref[NR_CPUS];
 326
 327         /* What modules depend on me? */
 328         struct list_head modules_which_use_me;
 329
 330         /* Who is waiting for us to be unloaded */
 331         struct task_struct *waiter;
 332
 333         /* Destruction function. */
 334         void (*exit)(void);
 335 #endif
 336
 337 #ifdef CONFIG_KALLSYMS
 338         /* We keep the symbol and string tables for kallsyms. */
 339         Elf_Sym *symtab;
 340         unsigned long num_symtab;
 341         char *strtab;
 342
 343         /* Section attributes */
 344         struct module_sect_attrs *sect_attrs;
 345 #endif
 346
 347         /* Per-cpu data. */
 348         void *percpu;
 349
 350         /* The command line arguments (may be mangled).  People like
 351            keeping pointers to this stuff */
 352         char *args;
 353 };
 354
 355 /* FIXME: It'd be nice to isolate modules during init, too, so they
 356    aren't used before they (may) fail.  But presently too much code
 357    (IDE & SCSI) require entry into the module during init.*/
 358 static inline int module_is_live(struct module *mod)
 359 {
 360         return mod->state != MODULE_STATE_GOING;
 361 }
 362
 363 /* Is this address in a module? (second is with no locks, for oops) */
 364 struct module *module_text_address(unsigned long addr);
 365 struct module *__module_text_address(unsigned long addr);
 366 int is_module_address(unsigned long addr);
 367
 368 /* Returns module and fills in value, defined and namebuf, or NULL if
 369    symnum out of range. */
 370 struct module *module_get_kallsym(unsigned int symnum, unsigned long *value,
 371                                 char *type, char *name, size_t namelen);
 372
 373 /* Look for this name: can be of form module:name. */
 374 unsigned long module_kallsyms_lookup_name(const char *name);
 375
 376 int is_exported(const char *name, const struct module *mod);
 377
 378 extern void __module_put_and_exit(struct module *mod, long code)
 379         __attribute__((noreturn));
 380 #define module_put_and_exit(code) __module_put_and_exit(THIS_MODULE, code);
 381
 382 #ifdef CONFIG_MODULE_UNLOAD
 383 unsigned int module_refcount(struct module *mod);
 384 void __symbol_put(const char *symbol);
 385 #define symbol_put(x) __symbol_put(MODULE_SYMBOL_PREFIX #x)
 386 void symbol_put_addr(void *addr);
 387
 388 /* Sometimes we know we already have a refcount, and it's easier not
 389    to handle the error case (which only happens with rmmod --wait). */
 390 static inline void __module_get(struct module *module)
 391 {
 392         if (module) {
 393                 BUG_ON(module_refcount(module) == 0);
 394                 local_inc(&module->ref[get_cpu()].count);
 395                 put_cpu();
 396         }
 397 }
 398
 399 static inline int try_module_get(struct module *module)
 400 {
 401         int ret = 1;
 402
 403         if (module) {
 404                 unsigned int cpu = get_cpu();
 405                 if (likely(module_is_live(module)))
 406                         local_inc(&module->ref[cpu].count);
 407                 else
 408                         ret = 0;
 409                 put_cpu();
 410         }
 411         return ret;
 412 }
 413
 414 static inline void module_put(struct module *module)
 415 {
 416         if (module) {
 417                 unsigned int cpu = get_cpu();
 418                 local_dec(&module->ref[cpu].count);
 419                 /* Maybe they're waiting for us to drop reference? */
 420                 if (unlikely(!module_is_live(module)))
 421                         wake_up_process(module->waiter);
 422                 put_cpu();
 423         }
 424 }
 425
 426 #else /*!CONFIG_MODULE_UNLOAD*/
 427 static inline int try_module_get(struct module *module)
 428 {
 429         return !module || module_is_live(module);
 430 }
 431 static inline void module_put(struct module *module)
 432 {
 433 }
 434 static inline void __module_get(struct module *module)
 435 {
 436 }
 437 #define symbol_put(x) do { } while(0)
 438 #define symbol_put_addr(p) do { } while(0)
 439
 440 #endif /* CONFIG_MODULE_UNLOAD */
 441
 442 /* This is a #define so the string doesn't get put in every .o file */
 443 #define module_name(mod)                        \
 444 ({                                              \
 445         struct module *__mod = (mod);           \
 446         __mod ? __mod->name : "kernel";         \
 447 })
 448
 449 #define __unsafe(mod)                                                        \
 450 do {                                                                         \
 451         if (mod && !(mod)->unsafe) {                                         \
 452                 printk(KERN_WARNING                                          \
 453                        "Module %s cannot be unloaded due to unsafe usage in" \
 454                        " %s:%u\n", (mod)->name, __FILE__, __LINE__);         \
 455                 (mod)->unsafe = 1;                                           \
 456         }                                                                    \
 457 } while(0)
 458
 459 /* For kallsyms to ask for address resolution.  NULL means not found. */
 460 const char *module_address_lookup(unsigned long addr,
 461                                   unsigned long *symbolsize,
 462                                   unsigned long *offset,
 463                                   char **modname);
 464
 465 /* For extable.c to search modules' exception tables. */
 466 const struct exception_table_entry *search_module_extables(unsigned long addr);
 467
 468 int register_module_notifier(struct notifier_block * nb);
 469 int unregister_module_notifier(struct notifier_block * nb);
 470
 471 extern void print_modules(void);
 472
 473 struct device_driver;
 474 void module_add_driver(struct module *, struct device_driver *);
 475 void module_remove_driver(struct device_driver *);
 476
 477 #else /* !CONFIG_MODULES... */
 478 #define EXPORT_SYMBOL(sym)
 479 #define EXPORT_SYMBOL_GPL(sym)
 480 #define EXPORT_SYMBOL_GPL_FUTURE(sym)
 481 #define EXPORT_UNUSED_SYMBOL(sym)
 482 #define EXPORT_UNUSED_SYMBOL_GPL(sym)
 483
 484 /* Given an address, look for it in the exception tables. */
 485 static inline const struct exception_table_entry *
 486 search_module_extables(unsigned long addr)
 487 {
 488         return NULL;
 489 }
 490
 491 /* Is this address in a module? */
 492 static inline struct module *module_text_address(unsigned long addr)
 493 {
 494         return NULL;
 495 }
 496
 497 /* Is this address in a module? (don't take a lock, we're oopsing) */
 498 static inline struct module *__module_text_address(unsigned long addr)
 499 {
 500         return NULL;
 501 }
 502
 503 static inline int is_module_address(unsigned long addr)
 504 {
 505         return 0;
 506 }
 507
 508 /* Get/put a kernel symbol (calls should be symmetric) */
 509 #define symbol_get(x) ({ extern typeof(x) x __attribute__((weak)); &(x); })
 510 #define symbol_put(x) do { } while(0)
 511 #define symbol_put_addr(x) do { } while(0)
 512
 513 static inline void __module_get(struct module *module)
 514 {
 515 }
 516
 517 static inline int try_module_get(struct module *module)
 518 {
 519         return 1;
 520 }
 521
 522 static inline void module_put(struct module *module)
 523 {
 524 }
 525
 526 #define module_name(mod) "kernel"
 527
 528 #define __unsafe(mod)
 529
 530 /* For kallsyms to ask for address resolution.  NULL means not found. */
 531 static inline const char *module_address_lookup(unsigned long addr,
 532                                                 unsigned long *symbolsize,
 533                                                 unsigned long *offset,
 534                                                 char **modname)
 535 {
 536         return NULL;
 537 }
 538
 539 static inline struct module *module_get_kallsym(unsigned int symnum,
 540                                                 unsigned long *value,
 541                                                 char *type, char *name,
 542                                                 size_t namelen)
 543 {
 544         return NULL;
 545 }
 546
 547 static inline unsigned long module_kallsyms_lookup_name(const char *name)
 548 {
 549         return 0;
 550 }
 551
 552 static inline int is_exported(const char *name, const struct module *mod)
 553 {
 554         return 0;
 555 }
 556
 557 static inline int register_module_notifier(struct notifier_block * nb)
 558 {
 559         /* no events will happen anyway, so this can always succeed */
 560         return 0;
 561 }
 562
 563 static inline int unregister_module_notifier(struct notifier_block * nb)
 564 {
 565         return 0;
 566 }
 567
 568 #define module_put_and_exit(code) do_exit(code)
 569
 570 static inline void print_modules(void)
 571 {
 572 }
 573
 574 struct device_driver;
 575 struct module;
 576
 577 static inline void module_add_driver(struct module *module, struct device_driver *driver)
 578 {
 579 }
 580
 581 static inline void module_remove_driver(struct device_driver *driver)
 582 {
 583 }
 584
 585 #endif /* CONFIG_MODULES */
 586
 587 #define symbol_request(x) try_then_request_module(symbol_get(x), "symbol:" #x)
 588
 589 /* BELOW HERE ALL THESE ARE OBSOLETE AND WILL VANISH */
 590
 591 #define __MODULE_STRING(x) __stringify(x)
 592
 593 #endif /* _LINUX_MODULE_H */