linux/include/linux/moduleparam.h
<<
>>
Prefs
   1#ifndef _LINUX_MODULE_PARAMS_H
   2#define _LINUX_MODULE_PARAMS_H
   3/* (C) Copyright 2001, 2002 Rusty Russell IBM Corporation */
   4#include <linux/init.h>
   5#include <linux/stringify.h>
   6#include <linux/kernel.h>
   7
   8/* You can override this manually, but generally this should match the
   9   module name. */
  10#ifdef MODULE
  11#define MODULE_PARAM_PREFIX /* empty */
  12#else
  13#define MODULE_PARAM_PREFIX KBUILD_MODNAME "."
  14#endif
  15
  16/* Chosen so that structs with an unsigned long line up. */
  17#define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long))
  18
  19#ifdef MODULE
  20#define __MODULE_INFO(tag, name, info)                                    \
  21static const char __UNIQUE_ID(name)[]                                     \
  22  __used __attribute__((section(".modinfo"), unused, aligned(1)))         \
  23  = __stringify(tag) "=" info
  24#else  /* !MODULE */
  25/* This struct is here for syntactic coherency, it is not used */
  26#define __MODULE_INFO(tag, name, info)                                    \
  27  struct __UNIQUE_ID(name) {}
  28#endif
  29#define __MODULE_PARM_TYPE(name, _type)                                   \
  30  __MODULE_INFO(parmtype, name##type, #name ":" _type)
  31
  32/* One for each parameter, describing how to use it.  Some files do
  33   multiple of these per line, so can't just use MODULE_INFO. */
  34#define MODULE_PARM_DESC(_parm, desc) \
  35        __MODULE_INFO(parm, _parm, #_parm ":" desc)
  36
  37struct kernel_param;
  38
  39/*
  40 * Flags available for kernel_param_ops
  41 *
  42 * NOARG - the parameter allows for no argument (foo instead of foo=1)
  43 */
  44enum {
  45        KERNEL_PARAM_OPS_FL_NOARG = (1 << 0)
  46};
  47
  48struct kernel_param_ops {
  49        /* How the ops should behave */
  50        unsigned int flags;
  51        /* Returns 0, or -errno.  arg is in kp->arg. */
  52        int (*set)(const char *val, const struct kernel_param *kp);
  53        /* Returns length written or -errno.  Buffer is 4k (ie. be short!) */
  54        int (*get)(char *buffer, const struct kernel_param *kp);
  55        /* Optional function to free kp->arg when module unloaded. */
  56        void (*free)(void *arg);
  57};
  58
  59/*
  60 * Flags available for kernel_param
  61 *
  62 * UNSAFE - the parameter is dangerous and setting it will taint the kernel
  63 * HWPARAM - Hardware param not permitted in lockdown mode
  64 */
  65enum {
  66        KERNEL_PARAM_FL_UNSAFE  = (1 << 0),
  67        KERNEL_PARAM_FL_HWPARAM = (1 << 1),
  68};
  69
  70struct kernel_param {
  71        const char *name;
  72        struct module *mod;
  73        const struct kernel_param_ops *ops;
  74        const u16 perm;
  75        s8 level;
  76        u8 flags;
  77        union {
  78                void *arg;
  79                const struct kparam_string *str;
  80                const struct kparam_array *arr;
  81        };
  82};
  83
  84extern const struct kernel_param __start___param[], __stop___param[];
  85
  86/* Special one for strings we want to copy into */
  87struct kparam_string {
  88        unsigned int maxlen;
  89        char *string;
  90};
  91
  92/* Special one for arrays */
  93struct kparam_array
  94{
  95        unsigned int max;
  96        unsigned int elemsize;
  97        unsigned int *num;
  98        const struct kernel_param_ops *ops;
  99        void *elem;
 100};
 101
 102/**
 103 * module_param - typesafe helper for a module/cmdline parameter
 104 * @value: the variable to alter, and exposed parameter name.
 105 * @type: the type of the parameter
 106 * @perm: visibility in sysfs.
 107 *
 108 * @value becomes the module parameter, or (prefixed by KBUILD_MODNAME and a
 109 * ".") the kernel commandline parameter.  Note that - is changed to _, so
 110 * the user can use "foo-bar=1" even for variable "foo_bar".
 111 *
 112 * @perm is 0 if the the variable is not to appear in sysfs, or 0444
 113 * for world-readable, 0644 for root-writable, etc.  Note that if it
 114 * is writable, you may need to use kernel_param_lock() around
 115 * accesses (esp. charp, which can be kfreed when it changes).
 116 *
 117 * The @type is simply pasted to refer to a param_ops_##type and a
 118 * param_check_##type: for convenience many standard types are provided but
 119 * you can create your own by defining those variables.
 120 *
 121 * Standard types are:
 122 *      byte, short, ushort, int, uint, long, ulong
 123 *      charp: a character pointer
 124 *      bool: a bool, values 0/1, y/n, Y/N.
 125 *      invbool: the above, only sense-reversed (N = true).
 126 */
 127#define module_param(name, type, perm)                          \
 128        module_param_named(name, name, type, perm)
 129
 130/**
 131 * module_param_unsafe - same as module_param but taints kernel
 132 */
 133#define module_param_unsafe(name, type, perm)                   \
 134        module_param_named_unsafe(name, name, type, perm)
 135
 136/**
 137 * module_param_named - typesafe helper for a renamed module/cmdline parameter
 138 * @name: a valid C identifier which is the parameter name.
 139 * @value: the actual lvalue to alter.
 140 * @type: the type of the parameter
 141 * @perm: visibility in sysfs.
 142 *
 143 * Usually it's a good idea to have variable names and user-exposed names the
 144 * same, but that's harder if the variable must be non-static or is inside a
 145 * structure.  This allows exposure under a different name.
 146 */
 147#define module_param_named(name, value, type, perm)                        \
 148        param_check_##type(name, &(value));                                \
 149        module_param_cb(name, &param_ops_##type, &value, perm);            \
 150        __MODULE_PARM_TYPE(name, #type)
 151
 152/**
 153 * module_param_named_unsafe - same as module_param_named but taints kernel
 154 */
 155#define module_param_named_unsafe(name, value, type, perm)              \
 156        param_check_##type(name, &(value));                             \
 157        module_param_cb_unsafe(name, &param_ops_##type, &value, perm);  \
 158        __MODULE_PARM_TYPE(name, #type)
 159
 160/**
 161 * module_param_cb - general callback for a module/cmdline parameter
 162 * @name: a valid C identifier which is the parameter name.
 163 * @ops: the set & get operations for this parameter.
 164 * @perm: visibility in sysfs.
 165 *
 166 * The ops can have NULL set or get functions.
 167 */
 168#define module_param_cb(name, ops, arg, perm)                                 \
 169        __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, 0)
 170
 171#define module_param_cb_unsafe(name, ops, arg, perm)                          \
 172        __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1,    \
 173                            KERNEL_PARAM_FL_UNSAFE)
 174
 175/**
 176 * <level>_param_cb - general callback for a module/cmdline parameter
 177 *                    to be evaluated before certain initcall level
 178 * @name: a valid C identifier which is the parameter name.
 179 * @ops: the set & get operations for this parameter.
 180 * @perm: visibility in sysfs.
 181 *
 182 * The ops can have NULL set or get functions.
 183 */
 184#define __level_param_cb(name, ops, arg, perm, level)                   \
 185        __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level, 0)
 186
 187#define core_param_cb(name, ops, arg, perm)             \
 188        __level_param_cb(name, ops, arg, perm, 1)
 189
 190#define postcore_param_cb(name, ops, arg, perm)         \
 191        __level_param_cb(name, ops, arg, perm, 2)
 192
 193#define arch_param_cb(name, ops, arg, perm)             \
 194        __level_param_cb(name, ops, arg, perm, 3)
 195
 196#define subsys_param_cb(name, ops, arg, perm)           \
 197        __level_param_cb(name, ops, arg, perm, 4)
 198
 199#define fs_param_cb(name, ops, arg, perm)               \
 200        __level_param_cb(name, ops, arg, perm, 5)
 201
 202#define device_param_cb(name, ops, arg, perm)           \
 203        __level_param_cb(name, ops, arg, perm, 6)
 204
 205#define late_param_cb(name, ops, arg, perm)             \
 206        __level_param_cb(name, ops, arg, perm, 7)
 207
 208/* On alpha, ia64 and ppc64 relocations to global data cannot go into
 209   read-only sections (which is part of respective UNIX ABI on these
 210   platforms). So 'const' makes no sense and even causes compile failures
 211   with some compilers. */
 212#if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64)
 213#define __moduleparam_const
 214#else
 215#define __moduleparam_const const
 216#endif
 217
 218/* This is the fundamental function for registering boot/module
 219   parameters. */
 220#define __module_param_call(prefix, name, ops, arg, perm, level, flags) \
 221        /* Default value instead of permissions? */                     \
 222        static const char __param_str_##name[] = prefix #name;          \
 223        static struct kernel_param __moduleparam_const __param_##name   \
 224        __used                                                          \
 225    __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
 226        = { __param_str_##name, THIS_MODULE, ops,                       \
 227            VERIFY_OCTAL_PERMISSIONS(perm), level, flags, { arg } }
 228
 229/* Obsolete - use module_param_cb() */
 230#define module_param_call(name, set, get, arg, perm)                    \
 231        static const struct kernel_param_ops __param_ops_##name =               \
 232                { .flags = 0, (void *)set, (void *)get };               \
 233        __module_param_call(MODULE_PARAM_PREFIX,                        \
 234                            name, &__param_ops_##name, arg,             \
 235                            (perm) + sizeof(__check_old_set_param(set))*0, -1, 0)
 236
 237/* We don't get oldget: it's often a new-style param_get_uint, etc. */
 238static inline int
 239__check_old_set_param(int (*oldset)(const char *, struct kernel_param *))
 240{
 241        return 0;
 242}
 243
 244#ifdef CONFIG_SYSFS
 245extern void kernel_param_lock(struct module *mod);
 246extern void kernel_param_unlock(struct module *mod);
 247#else
 248static inline void kernel_param_lock(struct module *mod)
 249{
 250}
 251static inline void kernel_param_unlock(struct module *mod)
 252{
 253}
 254#endif
 255
 256#ifndef MODULE
 257/**
 258 * core_param - define a historical core kernel parameter.
 259 * @name: the name of the cmdline and sysfs parameter (often the same as var)
 260 * @var: the variable
 261 * @type: the type of the parameter
 262 * @perm: visibility in sysfs
 263 *
 264 * core_param is just like module_param(), but cannot be modular and
 265 * doesn't add a prefix (such as "printk.").  This is for compatibility
 266 * with __setup(), and it makes sense as truly core parameters aren't
 267 * tied to the particular file they're in.
 268 */
 269#define core_param(name, var, type, perm)                               \
 270        param_check_##type(name, &(var));                               \
 271        __module_param_call("", name, &param_ops_##type, &var, perm, -1, 0)
 272
 273/**
 274 * core_param_unsafe - same as core_param but taints kernel
 275 */
 276#define core_param_unsafe(name, var, type, perm)                \
 277        param_check_##type(name, &(var));                               \
 278        __module_param_call("", name, &param_ops_##type, &var, perm,    \
 279                            -1, KERNEL_PARAM_FL_UNSAFE)
 280
 281#endif /* !MODULE */
 282
 283/**
 284 * module_param_string - a char array parameter
 285 * @name: the name of the parameter
 286 * @string: the string variable
 287 * @len: the maximum length of the string, incl. terminator
 288 * @perm: visibility in sysfs.
 289 *
 290 * This actually copies the string when it's set (unlike type charp).
 291 * @len is usually just sizeof(string).
 292 */
 293#define module_param_string(name, string, len, perm)                    \
 294        static const struct kparam_string __param_string_##name         \
 295                = { len, string };                                      \
 296        __module_param_call(MODULE_PARAM_PREFIX, name,                  \
 297                            &param_ops_string,                          \
 298                            .str = &__param_string_##name, perm, -1, 0);\
 299        __MODULE_PARM_TYPE(name, "string")
 300
 301/**
 302 * parameq - checks if two parameter names match
 303 * @name1: parameter name 1
 304 * @name2: parameter name 2
 305 *
 306 * Returns true if the two parameter names are equal.
 307 * Dashes (-) are considered equal to underscores (_).
 308 */
 309extern bool parameq(const char *name1, const char *name2);
 310
 311/**
 312 * parameqn - checks if two parameter names match
 313 * @name1: parameter name 1
 314 * @name2: parameter name 2
 315 * @n: the length to compare
 316 *
 317 * Similar to parameq(), except it compares @n characters.
 318 */
 319extern bool parameqn(const char *name1, const char *name2, size_t n);
 320
 321/* Called on module insert or kernel boot */
 322extern char *parse_args(const char *name,
 323                      char *args,
 324                      const struct kernel_param *params,
 325                      unsigned num,
 326                      s16 level_min,
 327                      s16 level_max,
 328                      void *arg,
 329                      int (*unknown)(char *param, char *val,
 330                                     const char *doing, void *arg));
 331
 332/* Called by module remove. */
 333#ifdef CONFIG_SYSFS
 334extern void destroy_params(const struct kernel_param *params, unsigned num);
 335#else
 336static inline void destroy_params(const struct kernel_param *params,
 337                                  unsigned num)
 338{
 339}
 340#endif /* !CONFIG_SYSFS */
 341
 342/* All the helper functions */
 343/* The macros to do compile-time type checking stolen from Jakub
 344   Jelinek, who IIRC came up with this idea for the 2.4 module init code. */
 345#define __param_check(name, p, type) \
 346        static inline type __always_unused *__check_##name(void) { return(p); }
 347
 348extern const struct kernel_param_ops param_ops_byte;
 349extern int param_set_byte(const char *val, const struct kernel_param *kp);
 350extern int param_get_byte(char *buffer, const struct kernel_param *kp);
 351#define param_check_byte(name, p) __param_check(name, p, unsigned char)
 352
 353extern const struct kernel_param_ops param_ops_short;
 354extern int param_set_short(const char *val, const struct kernel_param *kp);
 355extern int param_get_short(char *buffer, const struct kernel_param *kp);
 356#define param_check_short(name, p) __param_check(name, p, short)
 357
 358extern const struct kernel_param_ops param_ops_ushort;
 359extern int param_set_ushort(const char *val, const struct kernel_param *kp);
 360extern int param_get_ushort(char *buffer, const struct kernel_param *kp);
 361#define param_check_ushort(name, p) __param_check(name, p, unsigned short)
 362
 363extern const struct kernel_param_ops param_ops_int;
 364extern int param_set_int(const char *val, const struct kernel_param *kp);
 365extern int param_get_int(char *buffer, const struct kernel_param *kp);
 366#define param_check_int(name, p) __param_check(name, p, int)
 367
 368extern const struct kernel_param_ops param_ops_uint;
 369extern int param_set_uint(const char *val, const struct kernel_param *kp);
 370extern int param_get_uint(char *buffer, const struct kernel_param *kp);
 371#define param_check_uint(name, p) __param_check(name, p, unsigned int)
 372
 373extern const struct kernel_param_ops param_ops_long;
 374extern int param_set_long(const char *val, const struct kernel_param *kp);
 375extern int param_get_long(char *buffer, const struct kernel_param *kp);
 376#define param_check_long(name, p) __param_check(name, p, long)
 377
 378extern const struct kernel_param_ops param_ops_ulong;
 379extern int param_set_ulong(const char *val, const struct kernel_param *kp);
 380extern int param_get_ulong(char *buffer, const struct kernel_param *kp);
 381#define param_check_ulong(name, p) __param_check(name, p, unsigned long)
 382
 383extern const struct kernel_param_ops param_ops_ullong;
 384extern int param_set_ullong(const char *val, const struct kernel_param *kp);
 385extern int param_get_ullong(char *buffer, const struct kernel_param *kp);
 386#define param_check_ullong(name, p) __param_check(name, p, unsigned long long)
 387
 388extern const struct kernel_param_ops param_ops_charp;
 389extern int param_set_charp(const char *val, const struct kernel_param *kp);
 390extern int param_get_charp(char *buffer, const struct kernel_param *kp);
 391extern void param_free_charp(void *arg);
 392#define param_check_charp(name, p) __param_check(name, p, char *)
 393
 394/* We used to allow int as well as bool.  We're taking that away! */
 395extern const struct kernel_param_ops param_ops_bool;
 396extern int param_set_bool(const char *val, const struct kernel_param *kp);
 397extern int param_get_bool(char *buffer, const struct kernel_param *kp);
 398#define param_check_bool(name, p) __param_check(name, p, bool)
 399
 400extern const struct kernel_param_ops param_ops_bool_enable_only;
 401extern int param_set_bool_enable_only(const char *val,
 402                                      const struct kernel_param *kp);
 403/* getter is the same as for the regular bool */
 404#define param_check_bool_enable_only param_check_bool
 405
 406extern const struct kernel_param_ops param_ops_invbool;
 407extern int param_set_invbool(const char *val, const struct kernel_param *kp);
 408extern int param_get_invbool(char *buffer, const struct kernel_param *kp);
 409#define param_check_invbool(name, p) __param_check(name, p, bool)
 410
 411/* An int, which can only be set like a bool (though it shows as an int). */
 412extern const struct kernel_param_ops param_ops_bint;
 413extern int param_set_bint(const char *val, const struct kernel_param *kp);
 414#define param_get_bint param_get_int
 415#define param_check_bint param_check_int
 416
 417/**
 418 * module_param_array - a parameter which is an array of some type
 419 * @name: the name of the array variable
 420 * @type: the type, as per module_param()
 421 * @nump: optional pointer filled in with the number written
 422 * @perm: visibility in sysfs
 423 *
 424 * Input and output are as comma-separated values.  Commas inside values
 425 * don't work properly (eg. an array of charp).
 426 *
 427 * ARRAY_SIZE(@name) is used to determine the number of elements in the
 428 * array, so the definition must be visible.
 429 */
 430#define module_param_array(name, type, nump, perm)              \
 431        module_param_array_named(name, name, type, nump, perm)
 432
 433/**
 434 * module_param_array_named - renamed parameter which is an array of some type
 435 * @name: a valid C identifier which is the parameter name
 436 * @array: the name of the array variable
 437 * @type: the type, as per module_param()
 438 * @nump: optional pointer filled in with the number written
 439 * @perm: visibility in sysfs
 440 *
 441 * This exposes a different name than the actual variable name.  See
 442 * module_param_named() for why this might be necessary.
 443 */
 444#define module_param_array_named(name, array, type, nump, perm)         \
 445        param_check_##type(name, &(array)[0]);                          \
 446        static const struct kparam_array __param_arr_##name             \
 447        = { .max = ARRAY_SIZE(array), .num = nump,                      \
 448            .ops = &param_ops_##type,                                   \
 449            .elemsize = sizeof(array[0]), .elem = array };              \
 450        __module_param_call(MODULE_PARAM_PREFIX, name,                  \
 451                            &param_array_ops,                           \
 452                            .arr = &__param_arr_##name,                 \
 453                            perm, -1, 0);                               \
 454        __MODULE_PARM_TYPE(name, "array of " #type)
 455
 456enum hwparam_type {
 457        hwparam_ioport,         /* Module parameter configures an I/O port */
 458        hwparam_iomem,          /* Module parameter configures an I/O mem address */
 459        hwparam_ioport_or_iomem, /* Module parameter could be either, depending on other option */
 460        hwparam_irq,            /* Module parameter configures an IRQ */
 461        hwparam_dma,            /* Module parameter configures a DMA channel */
 462        hwparam_dma_addr,       /* Module parameter configures a DMA buffer address */
 463        hwparam_other,          /* Module parameter configures some other value */
 464};
 465
 466/**
 467 * module_param_hw_named - A parameter representing a hw parameters
 468 * @name: a valid C identifier which is the parameter name.
 469 * @value: the actual lvalue to alter.
 470 * @type: the type of the parameter
 471 * @hwtype: what the value represents (enum hwparam_type)
 472 * @perm: visibility in sysfs.
 473 *
 474 * Usually it's a good idea to have variable names and user-exposed names the
 475 * same, but that's harder if the variable must be non-static or is inside a
 476 * structure.  This allows exposure under a different name.
 477 */
 478#define module_param_hw_named(name, value, type, hwtype, perm)          \
 479        param_check_##type(name, &(value));                             \
 480        __module_param_call(MODULE_PARAM_PREFIX, name,                  \
 481                            &param_ops_##type, &value,                  \
 482                            perm, -1,                                   \
 483                            KERNEL_PARAM_FL_HWPARAM | (hwparam_##hwtype & 0));  \
 484        __MODULE_PARM_TYPE(name, #type)
 485
 486#define module_param_hw(name, type, hwtype, perm)               \
 487        module_param_hw_named(name, name, type, hwtype, perm)
 488
 489/**
 490 * module_param_hw_array - A parameter representing an array of hw parameters
 491 * @name: the name of the array variable
 492 * @type: the type, as per module_param()
 493 * @hwtype: what the value represents (enum hwparam_type)
 494 * @nump: optional pointer filled in with the number written
 495 * @perm: visibility in sysfs
 496 *
 497 * Input and output are as comma-separated values.  Commas inside values
 498 * don't work properly (eg. an array of charp).
 499 *
 500 * ARRAY_SIZE(@name) is used to determine the number of elements in the
 501 * array, so the definition must be visible.
 502 */
 503#define module_param_hw_array(name, type, hwtype, nump, perm)           \
 504        param_check_##type(name, &(name)[0]);                           \
 505        static const struct kparam_array __param_arr_##name             \
 506        = { .max = ARRAY_SIZE(name), .num = nump,                       \
 507            .ops = &param_ops_##type,                                   \
 508            .elemsize = sizeof(name[0]), .elem = name };                \
 509        __module_param_call(MODULE_PARAM_PREFIX, name,                  \
 510                            &param_array_ops,                           \
 511                            .arr = &__param_arr_##name,                 \
 512                            perm, -1,                                   \
 513                            KERNEL_PARAM_FL_HWPARAM | (hwparam_##hwtype & 0));  \
 514        __MODULE_PARM_TYPE(name, "array of " #type)
 515
 516
 517extern const struct kernel_param_ops param_array_ops;
 518
 519extern const struct kernel_param_ops param_ops_string;
 520extern int param_set_copystring(const char *val, const struct kernel_param *);
 521extern int param_get_string(char *buffer, const struct kernel_param *kp);
 522
 523/* for exporting parameters in /sys/module/.../parameters */
 524
 525struct module;
 526
 527#if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES)
 528extern int module_param_sysfs_setup(struct module *mod,
 529                                    const struct kernel_param *kparam,
 530                                    unsigned int num_params);
 531
 532extern void module_param_sysfs_remove(struct module *mod);
 533#else
 534static inline int module_param_sysfs_setup(struct module *mod,
 535                             const struct kernel_param *kparam,
 536                             unsigned int num_params)
 537{
 538        return 0;
 539}
 540
 541static inline void module_param_sysfs_remove(struct module *mod)
 542{ }
 543#endif
 544
 545#endif /* _LINUX_MODULE_PARAMS_H */
 546