Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  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 <linux/kobject.h>
 20 #include <linux/moduleparam.h>
 21 #include <asm/local.h>
 22 
 23 #include <asm/module.h>
 24 
 25 /* Not Yet Implemented */
 26 #define MODULE_SUPPORTED_DEVICE(name)
 27 
 28 /* v850 toolchain uses a `_' prefix for all user symbols */
 29 #ifndef MODULE_SYMBOL_PREFIX
 30 #define MODULE_SYMBOL_PREFIX ""
 31 #endif
 32 
 33 #define MODULE_NAME_LEN (64 - sizeof(unsigned long))
 34 
 35 struct kernel_symbol
 36 {
 37         unsigned long value;
 38         const char *name;
 39 };
 40 
 41 struct modversion_info
 42 {
 43         unsigned long crc;
 44         char name[MODULE_NAME_LEN];
 45 };
 46 
 47 struct module;
 48 
 49 struct module_attribute {
 50         struct attribute attr;
 51         ssize_t (*show)(struct module_attribute *, struct module *, char *);
 52         ssize_t (*store)(struct module_attribute *, struct module *,
 53                          const char *, size_t count);
 54 };
 55 
 56 struct module_kobject
 57 {
 58         struct kobject kobj;
 59         struct module *mod;
 60 };
 61 
 62 /* These are either module local, or the kernel's dummy ones. */
 63 extern int init_module(void);
 64 extern void cleanup_module(void);
 65 
 66 /* Archs provide a method of finding the correct exception table. */
 67 struct exception_table_entry;
 68 
 69 const struct exception_table_entry *
 70 search_extable(const struct exception_table_entry *first,
 71                const struct exception_table_entry *last,
 72                unsigned long value);
 73 void sort_extable(struct exception_table_entry *start,
 74                   struct exception_table_entry *finish);
 75 void sort_main_extable(void);
 76 
 77 extern struct subsystem module_subsys;
 78 
 79 #ifdef MODULE
 80 #define ___module_cat(a,b) __mod_ ## a ## b
 81 #define __module_cat(a,b) ___module_cat(a,b)
 82 #define __MODULE_INFO(tag, name, info)                                    \
 83 static const char __module_cat(name,__LINE__)[]                           \
 84   __attribute_used__                                                      \
 85   __attribute__((section(".modinfo"),unused)) = __stringify(tag) "=" info
 86 
 87 #define MODULE_GENERIC_TABLE(gtype,name)                        \
 88 extern const struct gtype##_id __mod_##gtype##_table            \
 89   __attribute__ ((unused, alias(__stringify(name))))
 90 
 91 extern struct module __this_module;
 92 #define THIS_MODULE (&__this_module)
 93 
 94 #else  /* !MODULE */
 95 
 96 #define MODULE_GENERIC_TABLE(gtype,name)
 97 #define __MODULE_INFO(tag, name, info)
 98 #define THIS_MODULE ((struct module *)0)
 99 #endif
100 
101 /* Generic info of form tag = "info" */
102 #define MODULE_INFO(tag, info) __MODULE_INFO(tag, tag, info)
103 
104 /* For userspace: you can also call me... */
105 #define MODULE_ALIAS(_alias) MODULE_INFO(alias, _alias)
106 
107 /*
108  * The following license idents are currently accepted as indicating free
109  * software modules
110  *
111  *      "GPL"                           [GNU Public License v2 or later]
112  *      "GPL v2"                        [GNU Public License v2]
113  *      "GPL and additional rights"     [GNU Public License v2 rights and more]
114  *      "Dual BSD/GPL"                  [GNU Public License v2
115  *                                       or BSD license choice]
116  *      "Dual MPL/GPL"                  [GNU Public License v2
117  *                                       or Mozilla license choice]
118  *
119  * The following other idents are available
120  *
121  *      "Proprietary"                   [Non free products]
122  *
123  * There are dual licensed components, but when running with Linux it is the
124  * GPL that is relevant so this is a non issue. Similarly LGPL linked with GPL
125  * is a GPL combined work.
126  *
127  * This exists for several reasons
128  * 1.   So modinfo can show license info for users wanting to vet their setup 
129  *      is free
130  * 2.   So the community can ignore bug reports including proprietary modules
131  * 3.   So vendors can do likewise based on their own policies
132  */
133 #define MODULE_LICENSE(_license) MODULE_INFO(license, _license)
134 
135 /* Author, ideally of form NAME <EMAIL>[, NAME <EMAIL>]*[ and NAME <EMAIL>] */
136 #define MODULE_AUTHOR(_author) MODULE_INFO(author, _author)
137   
138 /* What your module does. */
139 #define MODULE_DESCRIPTION(_description) MODULE_INFO(description, _description)
140 
141 /* One for each parameter, describing how to use it.  Some files do
142    multiple of these per line, so can't just use MODULE_INFO. */
143 #define MODULE_PARM_DESC(_parm, desc) \
144         __MODULE_INFO(parm, _parm, #_parm ":" desc)
145 
146 #define MODULE_DEVICE_TABLE(type,name)          \
147   MODULE_GENERIC_TABLE(type##_device,name)
148 
149 /* Version of form [<epoch>:]<version>[-<extra-version>].
150    Or for CVS/RCS ID version, everything but the number is stripped.
151   <epoch>: A (small) unsigned integer which allows you to start versions
152            anew. If not mentioned, it's zero.  eg. "2:1.0" is after
153            "1:2.0".
154   <version>: The <version> may contain only alphanumerics and the
155            character `.'.  Ordered by numeric sort for numeric parts,
156            ascii sort for ascii parts (as per RPM or DEB algorithm).
157   <extraversion>: Like <version>, but inserted for local
158            customizations, eg "rh3" or "rusty1".
159 
160   Using this automatically adds a checksum of the .c files and the
161   local headers in "srcversion".
162 */
163 #define MODULE_VERSION(_version) MODULE_INFO(version, _version)
164 
165 /* Given an address, look for it in the exception tables */
166 const struct exception_table_entry *search_exception_tables(unsigned long add);
167 
168 struct notifier_block;
169 
170 #ifdef CONFIG_MODULES
171 
172 /* Get/put a kernel symbol (calls must be symmetric) */
173 void *__symbol_get(const char *symbol);
174 void *__symbol_get_gpl(const char *symbol);
175 #define symbol_get(x) ((typeof(&x))(__symbol_get(MODULE_SYMBOL_PREFIX #x)))
176 
177 #ifndef __GENKSYMS__
178 #ifdef CONFIG_MODVERSIONS
179 /* Mark the CRC weak since genksyms apparently decides not to
180  * generate a checksums for some symbols */
181 #define __CRC_SYMBOL(sym, sec)                                  \
182         extern void *__crc_##sym __attribute__((weak));         \
183         static const unsigned long __kcrctab_##sym              \
184         __attribute_used__                                      \
185         __attribute__((section("__kcrctab" sec), unused))       \
186         = (unsigned long) &__crc_##sym;
187 #else
188 #define __CRC_SYMBOL(sym, sec)
189 #endif
190 
191 /* For every exported symbol, place a struct in the __ksymtab section */
192 #define __EXPORT_SYMBOL(sym, sec)                               \
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 #endif
209 
210 struct module_ref
211 {
212         local_t count;
213 } ____cacheline_aligned;
214 
215 enum module_state
216 {
217         MODULE_STATE_LIVE,
218         MODULE_STATE_COMING,
219         MODULE_STATE_GOING,
220 };
221 
222 /* Similar stuff for section attributes. */
223 #define MODULE_SECT_NAME_LEN 32
224 struct module_sect_attr
225 {
226         struct module_attribute mattr;
227         char name[MODULE_SECT_NAME_LEN];
228         unsigned long address;
229 };
230 
231 struct module_sect_attrs
232 {
233         struct attribute_group grp;
234         struct module_sect_attr attrs[0];
235 };
236 
237 struct module_param_attrs;
238 
239 struct module
240 {
241         enum module_state state;
242 
243         /* Member of list of modules */
244         struct list_head list;
245 
246         /* Unique handle for this module */
247         char name[MODULE_NAME_LEN];
248 
249         /* Sysfs stuff. */
250         struct module_kobject mkobj;
251         struct module_param_attrs *param_attrs;
252 
253         /* Exported symbols */
254         const struct kernel_symbol *syms;
255         unsigned int num_syms;
256         const unsigned long *crcs;
257 
258         /* GPL-only exported symbols. */
259         const struct kernel_symbol *gpl_syms;
260         unsigned int num_gpl_syms;
261         const unsigned long *gpl_crcs;
262 
263         /* Exception table */
264         unsigned int num_exentries;
265         const struct exception_table_entry *extable;
266 
267         /* Startup function. */
268         int (*init)(void);
269 
270         /* If this is non-NULL, vfree after init() returns */
271         void *module_init;
272 
273         /* Here is the actual code + data, vfree'd on unload. */
274         void *module_core;
275 
276         /* Here are the sizes of the init and core sections */
277         unsigned long init_size, core_size;
278 
279         /* The size of the executable code in each section.  */
280         unsigned long init_text_size, core_text_size;
281 
282         /* Arch-specific module values */
283         struct mod_arch_specific arch;
284 
285         /* Am I unsafe to unload? */
286         int unsafe;
287 
288         /* Am I GPL-compatible */
289         int license_gplok;
290 
291 #ifdef CONFIG_MODULE_UNLOAD
292         /* Reference counts */
293         struct module_ref ref[NR_CPUS];
294 
295         /* What modules depend on me? */
296         struct list_head modules_which_use_me;
297 
298         /* Who is waiting for us to be unloaded */
299         struct task_struct *waiter;
300 
301         /* Destruction function. */
302         void (*exit)(void);
303 #endif
304 
305 #ifdef CONFIG_KALLSYMS
306         /* We keep the symbol and string tables for kallsyms. */
307         Elf_Sym *symtab;
308         unsigned long num_symtab;
309         char *strtab;
310 
311         /* Section attributes */
312         struct module_sect_attrs *sect_attrs;
313 #endif
314 
315         /* Per-cpu data. */
316         void *percpu;
317 
318         /* The command line arguments (may be mangled).  People like
319            keeping pointers to this stuff */
320         char *args;
321 };
322 
323 /* FIXME: It'd be nice to isolate modules during init, too, so they
324    aren't used before they (may) fail.  But presently too much code
325    (IDE & SCSI) require entry into the module during init.*/
326 static inline int module_is_live(struct module *mod)
327 {
328         return mod->state != MODULE_STATE_GOING;
329 }
330 
331 /* Is this address in a module? (second is with no locks, for oops) */
332 struct module *module_text_address(unsigned long addr);
333 struct module *__module_text_address(unsigned long addr);
334 
335 /* Returns module and fills in value, defined and namebuf, or NULL if
336    symnum out of range. */
337 struct module *module_get_kallsym(unsigned int symnum,
338                                   unsigned long *value,
339                                   char *type,
340                                   char namebuf[128]);
341 
342 /* Look for this name: can be of form module:name. */
343 unsigned long module_kallsyms_lookup_name(const char *name);
344 
345 int is_exported(const char *name, const struct module *mod);
346 
347 extern void __module_put_and_exit(struct module *mod, long code)
348         __attribute__((noreturn));
349 #define module_put_and_exit(code) __module_put_and_exit(THIS_MODULE, code);
350 
351 #ifdef CONFIG_MODULE_UNLOAD
352 unsigned int module_refcount(struct module *mod);
353 void __symbol_put(const char *symbol);
354 #define symbol_put(x) __symbol_put(MODULE_SYMBOL_PREFIX #x)
355 void symbol_put_addr(void *addr);
356 
357 /* Sometimes we know we already have a refcount, and it's easier not
358    to handle the error case (which only happens with rmmod --wait). */
359 static inline void __module_get(struct module *module)
360 {
361         if (module) {
362                 BUG_ON(module_refcount(module) == 0);
363                 local_inc(&module->ref[get_cpu()].count);
364                 put_cpu();
365         }
366 }
367 
368 static inline int try_module_get(struct module *module)
369 {
370         int ret = 1;
371 
372         if (module) {
373                 unsigned int cpu = get_cpu();
374                 if (likely(module_is_live(module)))
375                         local_inc(&module->ref[cpu].count);
376                 else
377                         ret = 0;
378                 put_cpu();
379         }
380         return ret;
381 }
382 
383 static inline void module_put(struct module *module)
384 {
385         if (module) {
386                 unsigned int cpu = get_cpu();
387                 local_dec(&module->ref[cpu].count);
388                 /* Maybe they're waiting for us to drop reference? */
389                 if (unlikely(!module_is_live(module)))
390                         wake_up_process(module->waiter);
391                 put_cpu();
392         }
393 }
394 
395 #else /*!CONFIG_MODULE_UNLOAD*/
396 static inline int try_module_get(struct module *module)
397 {
398         return !module || module_is_live(module);
399 }
400 static inline void module_put(struct module *module)
401 {
402 }
403 static inline void __module_get(struct module *module)
404 {
405 }
406 #define symbol_put(x) do { } while(0)
407 #define symbol_put_addr(p) do { } while(0)
408 
409 #endif /* CONFIG_MODULE_UNLOAD */
410 
411 /* This is a #define so the string doesn't get put in every .o file */
412 #define module_name(mod)                        \
413 ({                                              \
414         struct module *__mod = (mod);           \
415         __mod ? __mod->name : "kernel";         \
416 })
417 
418 #define __unsafe(mod)                                                        \
419 do {                                                                         \
420         if (mod && !(mod)->unsafe) {                                         \
421                 printk(KERN_WARNING                                          \
422                        "Module %s cannot be unloaded due to unsafe usage in" \
423                        " %s:%u\n", (mod)->name, __FILE__, __LINE__);         \
424                 (mod)->unsafe = 1;                                           \
425         }                                                                    \
426 } while(0)
427 
428 /* For kallsyms to ask for address resolution.  NULL means not found. */
429 const char *module_address_lookup(unsigned long addr,
430                                   unsigned long *symbolsize,
431                                   unsigned long *offset,
432                                   char **modname);
433 
434 /* For extable.c to search modules' exception tables. */
435 const struct exception_table_entry *search_module_extables(unsigned long addr);
436 
437 int register_module_notifier(struct notifier_block * nb);
438 int unregister_module_notifier(struct notifier_block * nb);
439 
440 extern void print_modules(void);
441 
442 struct device_driver;
443 void module_add_driver(struct module *, struct device_driver *);
444 void module_remove_driver(struct device_driver *);
445 
446 #else /* !CONFIG_MODULES... */
447 #define EXPORT_SYMBOL(sym)
448 #define EXPORT_SYMBOL_GPL(sym)
449 
450 /* Given an address, look for it in the exception tables. */
451 static inline const struct exception_table_entry *
452 search_module_extables(unsigned long addr)
453 {
454         return NULL;
455 }
456 
457 /* Is this address in a module? */
458 static inline struct module *module_text_address(unsigned long addr)
459 {
460         return NULL;
461 }
462 
463 /* Is this address in a module? (don't take a lock, we're oopsing) */
464 static inline struct module *__module_text_address(unsigned long addr)
465 {
466         return NULL;
467 }
468 
469 /* Get/put a kernel symbol (calls should be symmetric) */
470 #define symbol_get(x) ({ extern typeof(x) x __attribute__((weak)); &(x); })
471 #define symbol_put(x) do { } while(0)
472 #define symbol_put_addr(x) do { } while(0)
473 
474 static inline void __module_get(struct module *module)
475 {
476 }
477 
478 static inline int try_module_get(struct module *module)
479 {
480         return 1;
481 }
482 
483 static inline void module_put(struct module *module)
484 {
485 }
486 
487 #define module_name(mod) "kernel"
488 
489 #define __unsafe(mod)
490 
491 /* For kallsyms to ask for address resolution.  NULL means not found. */
492 static inline const char *module_address_lookup(unsigned long addr,
493                                                 unsigned long *symbolsize,
494                                                 unsigned long *offset,
495                                                 char **modname)
496 {
497         return NULL;
498 }
499 
500 static inline struct module *module_get_kallsym(unsigned int symnum,
501                                                 unsigned long *value,
502                                                 char *type,
503                                                 char namebuf[128])
504 {
505         return NULL;
506 }
507 
508 static inline unsigned long module_kallsyms_lookup_name(const char *name)
509 {
510         return 0;
511 }
512 
513 static inline int is_exported(const char *name, const struct module *mod)
514 {
515         return 0;
516 }
517 
518 static inline int register_module_notifier(struct notifier_block * nb)
519 {
520         /* no events will happen anyway, so this can always succeed */
521         return 0;
522 }
523 
524 static inline int unregister_module_notifier(struct notifier_block * nb)
525 {
526         return 0;
527 }
528 
529 #define module_put_and_exit(code) do_exit(code)
530 
531 static inline void print_modules(void)
532 {
533 }
534 
535 struct device_driver;
536 struct module;
537 
538 static inline void module_add_driver(struct module *module, struct device_driver *driver)
539 {
540 }
541 
542 static inline void module_remove_driver(struct device_driver *driver)
543 {
544 }
545 
546 #endif /* CONFIG_MODULES */
547 
548 #define symbol_request(x) try_then_request_module(symbol_get(x), "symbol:" #x)
549 
550 /* BELOW HERE ALL THESE ARE OBSOLETE AND WILL VANISH */
551 
552 struct obsolete_modparm {
553         char name[64];
554         char type[64-sizeof(void *)];
555         void *addr;
556 };
557 
558 static inline void MODULE_PARM_(void) { }
559 #ifdef MODULE
560 /* DEPRECATED: Do not use. */
561 #define MODULE_PARM(var,type)                                               \
562 struct obsolete_modparm __parm_##var __attribute__((section("__obsparm"))) = \
563 { __stringify(var), type, &MODULE_PARM_ };
564 #else
565 #define MODULE_PARM(var,type) static void __attribute__((__unused__)) *__parm_##var = &MODULE_PARM_;
566 #endif
567 
568 #define __MODULE_STRING(x) __stringify(x)
569 
570 /* Use symbol_get and symbol_put instead.  You'll thank me. */
571 #define HAVE_INTER_MODULE
572 extern void __deprecated inter_module_register(const char *,
573                 struct module *, const void *);
574 extern void __deprecated inter_module_unregister(const char *);
575 extern const void * __deprecated inter_module_get(const char *);
576 extern const void * __deprecated inter_module_get_request(const char *,
577                 const char *);
578 extern void __deprecated inter_module_put(const char *);
579 
580 #endif /* _LINUX_MODULE_H */
581 
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