include/linux/module.h

   1 /*
   2  * Dynamic loading of modules into the kernel.
   3  *
   4  * Rewritten by Richard Henderson <rth@tamu.edu> Dec 1996
   5  */
   6
   7 #ifndef _LINUX_MODULE_H
   8 #define _LINUX_MODULE_H
   9
  10 #include <linux/config.h>
  11
  12 #ifdef __GENKSYMS__
  13 #  define _set_ver(sym) sym
  14 #  undef  MODVERSIONS
  15 #  define MODVERSIONS
  16 #else /* ! __GENKSYMS__ */
  17 # if !defined(MODVERSIONS) && defined(EXPORT_SYMTAB)
  18 #   define _set_ver(sym) sym
  19 #   include <linux/modversions.h>
  20 # endif
  21 #endif /* __GENKSYMS__ */
  22
  23 #include <asm/atomic.h>
  24
  25 /* Don't need to bring in all of uaccess.h just for this decl.  */
  26 struct exception_table_entry;
  27
  28 /* Used by get_kernel_syms, which is obsolete.  */
  29 struct kernel_sym
  30 {
  31         unsigned long value;
  32         char name[60];          /* should have been 64-sizeof(long); oh well */
  33 };
  34
  35 struct module_symbol
  36 {
  37         unsigned long value;
  38         const char *name;
  39 };
  40
  41 struct module_ref
  42 {
  43         struct module *dep;     /* "parent" pointer */
  44         struct module *ref;     /* "child" pointer */
  45         struct module_ref *next_ref;
  46 };
  47
  48 /* TBD */
  49 struct module_persist;
  50
  51 struct module
  52 {
  53         unsigned long size_of_struct;   /* == sizeof(module) */
  54         struct module *next;
  55         const char *name;
  56         unsigned long size;
  57
  58         union
  59         {
  60                 atomic_t usecount;
  61                 long pad;
  62         } uc;                           /* Needs to keep its size - so says rth */
  63
  64         unsigned long flags;            /* AUTOCLEAN et al */
  65
  66         unsigned nsyms;
  67         unsigned ndeps;
  68
  69         struct module_symbol *syms;
  70         struct module_ref *deps;
  71         struct module_ref *refs;
  72         int (*init)(void);
  73         void (*cleanup)(void);
  74         const struct exception_table_entry *ex_table_start;
  75         const struct exception_table_entry *ex_table_end;
  76 #ifdef __alpha__
  77         unsigned long gp;
  78 #endif
  79         /* Members past this point are extensions to the basic
  80            module support and are optional.  Use mod_opt_member()
  81            to examine them.  */
  82         const struct module_persist *persist_start;
  83         const struct module_persist *persist_end;
  84         int (*can_unload)(void);
  85 };
  86
  87 struct module_info
  88 {
  89         unsigned long addr;
  90         unsigned long size;
  91         unsigned long flags;
  92         long usecount;
  93 };
  94
  95 /* Bits of module.flags.  */
  96
  97 #define MOD_UNINITIALIZED       0
  98 #define MOD_RUNNING             1
  99 #define MOD_DELETED             2
 100 #define MOD_AUTOCLEAN           4
 101 #define MOD_VISITED             8
 102 #define MOD_USED_ONCE           16
 103 #define MOD_JUST_FREED          32
 104
 105 /* Values for query_module's which.  */
 106
 107 #define QM_MODULES      1
 108 #define QM_DEPS         2
 109 #define QM_REFS         3
 110 #define QM_SYMBOLS      4
 111 #define QM_INFO         5
 112
 113 /* When struct module is extended, we must test whether the new member
 114    is present in the header received from insmod before we can use it.
 115    This function returns true if the member is present.  */
 116
 117 #define mod_member_present(mod,member)                                  \
 118         ((unsigned long)(&((struct module *)0L)->member + 1)            \
 119          <= (mod)->size_of_struct)
 120
 121 /* Backwards compatibility definition.  */
 122
 123 #define GET_USE_COUNT(module)   (atomic_read(&(module)->uc.usecount))
 124
 125 /* Poke the use count of a module.  */
 126
 127 #define __MOD_INC_USE_COUNT(mod)                                        \
 128         (atomic_inc(&(mod)->uc.usecount), (mod)->flags |= MOD_VISITED|MOD_USED_ONCE)
 129 #define __MOD_DEC_USE_COUNT(mod)                                        \
 130         (atomic_dec(&(mod)->uc.usecount), (mod)->flags |= MOD_VISITED)
 131 #define __MOD_IN_USE(mod)                                               \
 132         (mod_member_present((mod), can_unload) && (mod)->can_unload     \
 133          ? (mod)->can_unload() : atomic_read(&(mod)->uc.usecount))
 134
 135 /* Indirect stringification.  */
 136
 137 #define __MODULE_STRING_1(x)    #x
 138 #define __MODULE_STRING(x)      __MODULE_STRING_1(x)
 139
 140 /* Find a symbol exported by the kernel or another module */
 141 extern unsigned long get_module_symbol(char *, char *);
 142
 143 #if defined(MODULE) && !defined(__GENKSYMS__)
 144
 145 /* Embedded module documentation macros.  */
 146
 147 /* For documentation purposes only.  */
 148
 149 #define MODULE_AUTHOR(name)                                                \
 150 const char __module_author[] __attribute__((section(".modinfo"))) =        \
 151 "author=" name
 152
 153 #define MODULE_DESCRIPTION(desc)                                           \
 154 const char __module_description[] __attribute__((section(".modinfo"))) =   \
 155 "description=" desc
 156
 157 /* Could potentially be used by kmod...  */
 158
 159 #define MODULE_SUPPORTED_DEVICE(dev)                                       \
 160 const char __module_device[] __attribute__((section(".modinfo"))) =        \
 161 "device=" dev
 162
 163 /* Used to verify parameters given to the module.  The TYPE arg should
 164    be a string in the following format:
 165         [min[-max]]{b,h,i,l,s}
 166    The MIN and MAX specifiers delimit the length of the array.  If MAX
 167    is omitted, it defaults to MIN; if both are omitted, the default is 1.
 168    The final character is a type specifier:
 169         b       byte
 170         h       short
 171         i       int
 172         l       long
 173         s       string
 174 */
 175
 176 #define MODULE_PARM(var,type)                   \
 177 const char __module_parm_##var[]                \
 178 __attribute__((section(".modinfo"))) =          \
 179 "parm_" __MODULE_STRING(var) "=" type
 180
 181 #define MODULE_PARM_DESC(var,desc)              \
 182 const char __module_parm_desc_##var[]           \
 183 __attribute__((section(".modinfo"))) =          \
 184 "parm_desc_" __MODULE_STRING(var) "=" desc
 185
 186 /* The attributes of a section are set the first time the section is
 187    seen; we want .modinfo to not be allocated.  */
 188
 189 __asm__(".section .modinfo\n\t.previous");
 190
 191 /* Define the module variable, and usage macros.  */
 192 extern struct module __this_module;
 193
 194 #define THIS_MODULE             (&__this_module)
 195 #define MOD_INC_USE_COUNT       __MOD_INC_USE_COUNT(THIS_MODULE)
 196 #define MOD_DEC_USE_COUNT       __MOD_DEC_USE_COUNT(THIS_MODULE)
 197 #define MOD_IN_USE              __MOD_IN_USE(THIS_MODULE)
 198
 199 #ifndef __NO_VERSION__
 200 #include <linux/version.h>
 201 const char __module_kernel_version[] __attribute__((section(".modinfo"))) =
 202 "kernel_version=" UTS_RELEASE;
 203 #ifdef MODVERSIONS
 204 const char __module_using_checksums[] __attribute__((section(".modinfo"))) =
 205 "using_checksums=1";
 206 #endif
 207 #endif
 208
 209 #else /* MODULE */
 210
 211 #define MODULE_AUTHOR(name)
 212 #define MODULE_DESCRIPTION(desc)
 213 #define MODULE_SUPPORTED_DEVICE(name)
 214 #define MODULE_PARM(var,type)
 215 #define MODULE_PARM_DESC(var,desc)
 216
 217 #ifndef __GENKSYMS__
 218
 219 #define THIS_MODULE             NULL
 220 #define MOD_INC_USE_COUNT       do { } while (0)
 221 #define MOD_DEC_USE_COUNT       do { } while (0)
 222 #define MOD_IN_USE              1
 223
 224 extern struct module *module_list;
 225
 226 #endif /* !__GENKSYMS__ */
 227
 228 #endif /* MODULE */
 229
 230 /* Export a symbol either from the kernel or a module.
 231
 232    In the kernel, the symbol is added to the kernel's global symbol table.
 233
 234    In a module, it controls which variables are exported.  If no
 235    variables are explicitly exported, the action is controled by the
 236    insmod -[xX] flags.  Otherwise, only the variables listed are exported.
 237    This obviates the need for the old register_symtab() function.  */
 238
 239 #if defined(__GENKSYMS__)
 240
 241 /* We want the EXPORT_SYMBOL tag left intact for recognition.  */
 242
 243 #elif !defined(AUTOCONF_INCLUDED)
 244
 245 #define __EXPORT_SYMBOL(sym,str)   error config_must_be_included_before_module
 246 #define EXPORT_SYMBOL(var)         error config_must_be_included_before_module
 247 #define EXPORT_SYMBOL_NOVERS(var)  error config_must_be_included_before_module
 248
 249 #elif !defined(CONFIG_MODULES)
 250
 251 #define __EXPORT_SYMBOL(sym,str)
 252 #define EXPORT_SYMBOL(var)
 253 #define EXPORT_SYMBOL_NOVERS(var)
 254
 255 #elif !defined(EXPORT_SYMTAB)
 256
 257 /* If things weren't set up in the Makefiles to get EXPORT_SYMTAB defined,
 258    then they weren't set up to run genksyms properly so MODVERSIONS breaks.  */
 259 #define __EXPORT_SYMBOL(sym,str)   error EXPORT_SYMTAB_not_defined
 260 #define EXPORT_SYMBOL(var)         error EXPORT_SYMTAB_not_defined
 261 #define EXPORT_SYMBOL_NOVERS(var)  error EXPORT_SYMTAB_not_defined
 262
 263 #else
 264
 265 #define __EXPORT_SYMBOL(sym, str)                       \
 266 const char __kstrtab_##sym[]                            \
 267 __attribute__((section(".kstrtab"))) = str;             \
 268 const struct module_symbol __ksymtab_##sym              \
 269 __attribute__((section("__ksymtab"))) =                 \
 270 { (unsigned long)&sym, __kstrtab_##sym }
 271
 272 #if defined(MODVERSIONS) || !defined(CONFIG_MODVERSIONS)
 273 #define EXPORT_SYMBOL(var)  __EXPORT_SYMBOL(var, __MODULE_STRING(var))
 274 #else
 275 #define EXPORT_SYMBOL(var)  __EXPORT_SYMBOL(var, __MODULE_STRING(__VERSIONED_SYMBOL(var)))
 276 #endif
 277
 278 #define EXPORT_SYMBOL_NOVERS(var)  __EXPORT_SYMBOL(var, __MODULE_STRING(var))
 279
 280 #endif /* __GENKSYMS__ */
 281
 282 #ifdef MODULE
 283 /* Force a module to export no symbols.  */
 284 #define EXPORT_NO_SYMBOLS  __asm__(".section __ksymtab\n.previous")
 285 #else
 286 #define EXPORT_NO_SYMBOLS
 287 #endif /* MODULE */
 288
 289 #endif /* _LINUX_MODULE_H */