include/linux/moduleparam.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_MODULE_PARAMS_H
   3 #define _LINUX_MODULE_PARAMS_H
   4 /* (C) Copyright 2001, 2002 Rusty Russell IBM Corporation */
   5 #include <linux/init.h>
   6 #include <linux/stringify.h>
   7 #include <linux/kernel.h>
   8
   9 /* You can override this manually, but generally this should match the
  10    module name. */
  11 #ifdef MODULE
  12 #define MODULE_PARAM_PREFIX /* empty */
  13 #define __MODULE_INFO_PREFIX /* empty */
  14 #else
  15 #define MODULE_PARAM_PREFIX KBUILD_MODNAME "."
  16 /* We cannot use MODULE_PARAM_PREFIX because some modules override it. */
  17 #define __MODULE_INFO_PREFIX KBUILD_MODNAME "."
  18 #endif
  19
  20 /* Chosen so that structs with an unsigned long line up. */
  21 #define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long))
  22
  23 #define __MODULE_INFO(tag, name, info)                                    \
  24         static const char __UNIQUE_ID(name)[]                             \
  25                 __used __section(".modinfo") __aligned(1)                 \
  26                 = __MODULE_INFO_PREFIX __stringify(tag) "=" info
  27
  28 #define __MODULE_PARM_TYPE(name, _type)                                   \
  29         __MODULE_INFO(parmtype, name##type, #name ":" _type)
  30
  31 /* One for each parameter, describing how to use it.  Some files do
  32    multiple of these per line, so can't just use MODULE_INFO. */
  33 #define MODULE_PARM_DESC(_parm, desc) \
  34         __MODULE_INFO(parm, _parm, #_parm ":" desc)
  35
  36 struct kernel_param;
  37
  38 /*
  39  * Flags available for kernel_param_ops
  40  *
  41  * NOARG - the parameter allows for no argument (foo instead of foo=1)
  42  */
  43 enum {
  44         KERNEL_PARAM_OPS_FL_NOARG = (1 << 0)
  45 };
  46
  47 struct kernel_param_ops {
  48         /* How the ops should behave */
  49         unsigned int flags;
  50         /* Returns 0, or -errno.  arg is in kp->arg. */
  51         int (*set)(const char *val, const struct kernel_param *kp);
  52         /* Returns length written or -errno.  Buffer is 4k (ie. be short!) */
  53         int (*get)(char *buffer, const struct kernel_param *kp);
  54         /* Optional function to free kp->arg when module unloaded. */
  55         void (*free)(void *arg);
  56 };
  57
  58 /*
  59  * Flags available for kernel_param
  60  *
  61  * UNSAFE - the parameter is dangerous and setting it will taint the kernel
  62  * HWPARAM - Hardware param not permitted in lockdown mode
  63  */
  64 enum {
  65         KERNEL_PARAM_FL_UNSAFE  = (1 << 0),
  66         KERNEL_PARAM_FL_HWPARAM = (1 << 1),
  67 };
  68
  69 struct kernel_param {
  70         const char *name;
  71         struct module *mod;
  72         const struct kernel_param_ops *ops;
  73         const u16 perm;
  74         s8 level;
  75         u8 flags;
  76         union {
  77                 void *arg;
  78                 const struct kparam_string *str;
  79                 const struct kparam_array *arr;
  80         };
  81 };
  82
  83 extern const struct kernel_param __start___param[], __stop___param[];
  84
  85 /* Special one for strings we want to copy into */
  86 struct kparam_string {
  87         unsigned int maxlen;
  88         char *string;
  89 };
  90
  91 /* Special one for arrays */
  92 struct kparam_array
  93 {
  94         unsigned int max;
  95         unsigned int elemsize;
  96         unsigned int *num;
  97         const struct kernel_param_ops *ops;
  98         void *elem;
  99 };
 100
 101 /**
 102  * module_param - typesafe helper for a module/cmdline parameter
 103  * @name: the variable to alter, and exposed parameter name.
 104  * @type: the type of the parameter
 105  * @perm: visibility in sysfs.
 106  *
 107  * @name becomes the module parameter, or (prefixed by KBUILD_MODNAME and a
 108  * ".") the kernel commandline parameter.  Note that - is changed to _, so
 109  * the user can use "foo-bar=1" even for variable "foo_bar".
 110  *
 111  * @perm is 0 if the variable is not to appear in sysfs, or 0444
 112  * for world-readable, 0644 for root-writable, etc.  Note that if it
 113  * is writable, you may need to use kernel_param_lock() around
 114  * accesses (esp. charp, which can be kfreed when it changes).
 115  *
 116  * The @type is simply pasted to refer to a param_ops_##type and a
 117  * param_check_##type: for convenience many standard types are provided but
 118  * you can create your own by defining those variables.
 119  *
 120  * Standard types are:
 121  *      byte, hexint, short, ushort, int, uint, long, ulong
 122  *      charp: a character pointer
 123  *      bool: a bool, values 0/1, y/n, Y/N.
 124  *      invbool: the above, only sense-reversed (N = true).
 125  */
 126 #define module_param(name, type, perm)                          \
 127         module_param_named(name, name, type, perm)
 128
 129 /**
 130  * module_param_unsafe - same as module_param but taints kernel
 131  * @name: the variable to alter, and exposed parameter name.
 132  * @type: the type of the parameter
 133  * @perm: visibility in sysfs.
 134  */
 135 #define module_param_unsafe(name, type, perm)                   \
 136         module_param_named_unsafe(name, name, type, perm)
 137
 138 /**
 139  * module_param_named - typesafe helper for a renamed module/cmdline parameter
 140  * @name: a valid C identifier which is the parameter name.
 141  * @value: the actual lvalue to alter.
 142  * @type: the type of the parameter
 143  * @perm: visibility in sysfs.
 144  *
 145  * Usually it's a good idea to have variable names and user-exposed names the
 146  * same, but that's harder if the variable must be non-static or is inside a
 147  * structure.  This allows exposure under a different name.
 148  */
 149 #define module_param_named(name, value, type, perm)                        \
 150         param_check_##type(name, &(value));                                \
 151         module_param_cb(name, &param_ops_##type, &value, perm);            \
 152         __MODULE_PARM_TYPE(name, #type)
 153
 154 /**
 155  * module_param_named_unsafe - same as module_param_named but taints kernel
 156  * @name: a valid C identifier which is the parameter name.
 157  * @value: the actual lvalue to alter.
 158  * @type: the type of the parameter
 159  * @perm: visibility in sysfs.
 160  */
 161 #define module_param_named_unsafe(name, value, type, perm)              \
 162         param_check_##type(name, &(value));                             \
 163         module_param_cb_unsafe(name, &param_ops_##type, &value, perm);  \
 164         __MODULE_PARM_TYPE(name, #type)
 165
 166 /**
 167  * module_param_cb - general callback for a module/cmdline parameter
 168  * @name: a valid C identifier which is the parameter name.
 169  * @ops: the set & get operations for this parameter.
 170  * @arg: args for @ops
 171  * @perm: visibility in sysfs.
 172  *
 173  * The ops can have NULL set or get functions.
 174  */
 175 #define module_param_cb(name, ops, arg, perm)                                 \
 176         __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, 0)
 177
 178 #define module_param_cb_unsafe(name, ops, arg, perm)                          \
 179         __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1,    \
 180                             KERNEL_PARAM_FL_UNSAFE)
 181
 182 #define __level_param_cb(name, ops, arg, perm, level)                   \
 183         __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level, 0)
 184 /**
 185  * core_param_cb - general callback for a module/cmdline parameter
 186  *                 to be evaluated before core initcall level
 187  * @name: a valid C identifier which is the parameter name.
 188  * @ops: the set & get operations for this parameter.
 189  * @arg: args for @ops
 190  * @perm: visibility in sysfs.
 191  *
 192  * The ops can have NULL set or get functions.
 193  */
 194 #define core_param_cb(name, ops, arg, perm)             \
 195         __level_param_cb(name, ops, arg, perm, 1)
 196
 197 /**
 198  * postcore_param_cb - general callback for a module/cmdline parameter
 199  *                     to be evaluated before postcore initcall level
 200  * @name: a valid C identifier which is the parameter name.
 201  * @ops: the set & get operations for this parameter.
 202  * @arg: args for @ops
 203  * @perm: visibility in sysfs.
 204  *
 205  * The ops can have NULL set or get functions.
 206  */
 207 #define postcore_param_cb(name, ops, arg, perm)         \
 208         __level_param_cb(name, ops, arg, perm, 2)
 209
 210 /**
 211  * arch_param_cb - general callback for a module/cmdline parameter
 212  *                 to be evaluated before arch initcall level
 213  * @name: a valid C identifier which is the parameter name.
 214  * @ops: the set & get operations for this parameter.
 215  * @arg: args for @ops
 216  * @perm: visibility in sysfs.
 217  *
 218  * The ops can have NULL set or get functions.
 219  */
 220 #define arch_param_cb(name, ops, arg, perm)             \
 221         __level_param_cb(name, ops, arg, perm, 3)
 222
 223 /**
 224  * subsys_param_cb - general callback for a module/cmdline parameter
 225  *                   to be evaluated before subsys initcall level
 226  * @name: a valid C identifier which is the parameter name.
 227  * @ops: the set & get operations for this parameter.
 228  * @arg: args for @ops
 229  * @perm: visibility in sysfs.
 230  *
 231  * The ops can have NULL set or get functions.
 232  */
 233 #define subsys_param_cb(name, ops, arg, perm)           \
 234         __level_param_cb(name, ops, arg, perm, 4)
 235
 236 /**
 237  * fs_param_cb - general callback for a module/cmdline parameter
 238  *               to be evaluated before fs initcall level
 239  * @name: a valid C identifier which is the parameter name.
 240  * @ops: the set & get operations for this parameter.
 241  * @arg: args for @ops
 242  * @perm: visibility in sysfs.
 243  *
 244  * The ops can have NULL set or get functions.
 245  */
 246 #define fs_param_cb(name, ops, arg, perm)               \
 247         __level_param_cb(name, ops, arg, perm, 5)
 248
 249 /**
 250  * device_param_cb - general callback for a module/cmdline parameter
 251  *                   to be evaluated before device initcall level
 252  * @name: a valid C identifier which is the parameter name.
 253  * @ops: the set & get operations for this parameter.
 254  * @arg: args for @ops
 255  * @perm: visibility in sysfs.
 256  *
 257  * The ops can have NULL set or get functions.
 258  */
 259 #define device_param_cb(name, ops, arg, perm)           \
 260         __level_param_cb(name, ops, arg, perm, 6)
 261
 262 /**
 263  * late_param_cb - general callback for a module/cmdline parameter
 264  *                 to be evaluated before late initcall level
 265  * @name: a valid C identifier which is the parameter name.
 266  * @ops: the set & get operations for this parameter.
 267  * @arg: args for @ops
 268  * @perm: visibility in sysfs.
 269  *
 270  * The ops can have NULL set or get functions.
 271  */
 272 #define late_param_cb(name, ops, arg, perm)             \
 273         __level_param_cb(name, ops, arg, perm, 7)
 274
 275 /* On alpha, ia64 and ppc64 relocations to global data cannot go into
 276    read-only sections (which is part of respective UNIX ABI on these
 277    platforms). So 'const' makes no sense and even causes compile failures
 278    with some compilers. */
 279 #if defined(CONFIG_ALPHA) || defined(CONFIG_PPC64)
 280 #define __moduleparam_const
 281 #else
 282 #define __moduleparam_const const
 283 #endif
 284
 285 /* This is the fundamental function for registering boot/module
 286    parameters. */
 287 #define __module_param_call(prefix, name, ops, arg, perm, level, flags) \
 288         /* Default value instead of permissions? */                     \
 289         static const char __param_str_##name[] = prefix #name;          \
 290         static struct kernel_param __moduleparam_const __param_##name   \
 291         __used __section("__param")                                     \
 292         __aligned(__alignof__(struct kernel_param))                     \
 293         = { __param_str_##name, THIS_MODULE, ops,                       \
 294             VERIFY_OCTAL_PERMISSIONS(perm), level, flags, { arg } }
 295
 296 /*
 297  * Useful for describing a set/get pair used only once (i.e. for this
 298  * parameter). For repeated set/get pairs (i.e. the same struct
 299  * kernel_param_ops), use module_param_cb() instead.
 300  */
 301 #define module_param_call(name, _set, _get, arg, perm)                  \
 302         static const struct kernel_param_ops __param_ops_##name =       \
 303                 { .flags = 0, .set = _set, .get = _get };               \
 304         __module_param_call(MODULE_PARAM_PREFIX,                        \
 305                             name, &__param_ops_##name, arg, perm, -1, 0)
 306
 307 #ifdef CONFIG_SYSFS
 308 extern void kernel_param_lock(struct module *mod);
 309 extern void kernel_param_unlock(struct module *mod);
 310 #else
 311 static inline void kernel_param_lock(struct module *mod)
 312 {
 313 }
 314 static inline void kernel_param_unlock(struct module *mod)
 315 {
 316 }
 317 #endif
 318
 319 #ifndef MODULE
 320 /**
 321  * core_param - define a historical core kernel parameter.
 322  * @name: the name of the cmdline and sysfs parameter (often the same as var)
 323  * @var: the variable
 324  * @type: the type of the parameter
 325  * @perm: visibility in sysfs
 326  *
 327  * core_param is just like module_param(), but cannot be modular and
 328  * doesn't add a prefix (such as "printk.").  This is for compatibility
 329  * with __setup(), and it makes sense as truly core parameters aren't
 330  * tied to the particular file they're in.
 331  */
 332 #define core_param(name, var, type, perm)                               \
 333         param_check_##type(name, &(var));                               \
 334         __module_param_call("", name, &param_ops_##type, &var, perm, -1, 0)
 335
 336 /**
 337  * core_param_unsafe - same as core_param but taints kernel
 338  * @name: the name of the cmdline and sysfs parameter (often the same as var)
 339  * @var: the variable
 340  * @type: the type of the parameter
 341  * @perm: visibility in sysfs
 342  */
 343 #define core_param_unsafe(name, var, type, perm)                \
 344         param_check_##type(name, &(var));                               \
 345         __module_param_call("", name, &param_ops_##type, &var, perm,    \
 346                             -1, KERNEL_PARAM_FL_UNSAFE)
 347
 348 #endif /* !MODULE */
 349
 350 /**
 351  * module_param_string - a char array parameter
 352  * @name: the name of the parameter
 353  * @string: the string variable
 354  * @len: the maximum length of the string, incl. terminator
 355  * @perm: visibility in sysfs.
 356  *
 357  * This actually copies the string when it's set (unlike type charp).
 358  * @len is usually just sizeof(string).
 359  */
 360 #define module_param_string(name, string, len, perm)                    \
 361         static const struct kparam_string __param_string_##name         \
 362                 = { len, string };                                      \
 363         __module_param_call(MODULE_PARAM_PREFIX, name,                  \
 364                             &param_ops_string,                          \
 365                             .str = &__param_string_##name, perm, -1, 0);\
 366         __MODULE_PARM_TYPE(name, "string")
 367
 368 /**
 369  * parameq - checks if two parameter names match
 370  * @name1: parameter name 1
 371  * @name2: parameter name 2
 372  *
 373  * Returns true if the two parameter names are equal.
 374  * Dashes (-) are considered equal to underscores (_).
 375  */
 376 extern bool parameq(const char *name1, const char *name2);
 377
 378 /**
 379  * parameqn - checks if two parameter names match
 380  * @name1: parameter name 1
 381  * @name2: parameter name 2
 382  * @n: the length to compare
 383  *
 384  * Similar to parameq(), except it compares @n characters.
 385  */
 386 extern bool parameqn(const char *name1, const char *name2, size_t n);
 387
 388 typedef int (*parse_unknown_fn)(char *param, char *val, const char *doing, void *arg);
 389
 390 /* Called on module insert or kernel boot */
 391 extern char *parse_args(const char *name,
 392                       char *args,
 393                       const struct kernel_param *params,
 394                       unsigned num,
 395                       s16 level_min,
 396                       s16 level_max,
 397                       void *arg, parse_unknown_fn unknown);
 398
 399 /* Called by module remove. */
 400 #ifdef CONFIG_SYSFS
 401 extern void destroy_params(const struct kernel_param *params, unsigned num);
 402 #else
 403 static inline void destroy_params(const struct kernel_param *params,
 404                                   unsigned num)
 405 {
 406 }
 407 #endif /* !CONFIG_SYSFS */
 408
 409 /* All the helper functions */
 410 /* The macros to do compile-time type checking stolen from Jakub
 411    Jelinek, who IIRC came up with this idea for the 2.4 module init code. */
 412 #define __param_check(name, p, type) \
 413         static inline type __always_unused *__check_##name(void) { return(p); }
 414
 415 extern const struct kernel_param_ops param_ops_byte;
 416 extern int param_set_byte(const char *val, const struct kernel_param *kp);
 417 extern int param_get_byte(char *buffer, const struct kernel_param *kp);
 418 #define param_check_byte(name, p) __param_check(name, p, unsigned char)
 419
 420 extern const struct kernel_param_ops param_ops_short;
 421 extern int param_set_short(const char *val, const struct kernel_param *kp);
 422 extern int param_get_short(char *buffer, const struct kernel_param *kp);
 423 #define param_check_short(name, p) __param_check(name, p, short)
 424
 425 extern const struct kernel_param_ops param_ops_ushort;
 426 extern int param_set_ushort(const char *val, const struct kernel_param *kp);
 427 extern int param_get_ushort(char *buffer, const struct kernel_param *kp);
 428 #define param_check_ushort(name, p) __param_check(name, p, unsigned short)
 429
 430 extern const struct kernel_param_ops param_ops_int;
 431 extern int param_set_int(const char *val, const struct kernel_param *kp);
 432 extern int param_get_int(char *buffer, const struct kernel_param *kp);
 433 #define param_check_int(name, p) __param_check(name, p, int)
 434
 435 extern const struct kernel_param_ops param_ops_uint;
 436 extern int param_set_uint(const char *val, const struct kernel_param *kp);
 437 extern int param_get_uint(char *buffer, const struct kernel_param *kp);
 438 int param_set_uint_minmax(const char *val, const struct kernel_param *kp,
 439                 unsigned int min, unsigned int max);
 440 #define param_check_uint(name, p) __param_check(name, p, unsigned int)
 441
 442 extern const struct kernel_param_ops param_ops_long;
 443 extern int param_set_long(const char *val, const struct kernel_param *kp);
 444 extern int param_get_long(char *buffer, const struct kernel_param *kp);
 445 #define param_check_long(name, p) __param_check(name, p, long)
 446
 447 extern const struct kernel_param_ops param_ops_ulong;
 448 extern int param_set_ulong(const char *val, const struct kernel_param *kp);
 449 extern int param_get_ulong(char *buffer, const struct kernel_param *kp);
 450 #define param_check_ulong(name, p) __param_check(name, p, unsigned long)
 451
 452 extern const struct kernel_param_ops param_ops_ullong;
 453 extern int param_set_ullong(const char *val, const struct kernel_param *kp);
 454 extern int param_get_ullong(char *buffer, const struct kernel_param *kp);
 455 #define param_check_ullong(name, p) __param_check(name, p, unsigned long long)
 456
 457 extern const struct kernel_param_ops param_ops_hexint;
 458 extern int param_set_hexint(const char *val, const struct kernel_param *kp);
 459 extern int param_get_hexint(char *buffer, const struct kernel_param *kp);
 460 #define param_check_hexint(name, p) param_check_uint(name, p)
 461
 462 extern const struct kernel_param_ops param_ops_charp;
 463 extern int param_set_charp(const char *val, const struct kernel_param *kp);
 464 extern int param_get_charp(char *buffer, const struct kernel_param *kp);
 465 extern void param_free_charp(void *arg);
 466 #define param_check_charp(name, p) __param_check(name, p, char *)
 467
 468 /* We used to allow int as well as bool.  We're taking that away! */
 469 extern const struct kernel_param_ops param_ops_bool;
 470 extern int param_set_bool(const char *val, const struct kernel_param *kp);
 471 extern int param_get_bool(char *buffer, const struct kernel_param *kp);
 472 #define param_check_bool(name, p) __param_check(name, p, bool)
 473
 474 extern const struct kernel_param_ops param_ops_bool_enable_only;
 475 extern int param_set_bool_enable_only(const char *val,
 476                                       const struct kernel_param *kp);
 477 /* getter is the same as for the regular bool */
 478 #define param_check_bool_enable_only param_check_bool
 479
 480 extern const struct kernel_param_ops param_ops_invbool;
 481 extern int param_set_invbool(const char *val, const struct kernel_param *kp);
 482 extern int param_get_invbool(char *buffer, const struct kernel_param *kp);
 483 #define param_check_invbool(name, p) __param_check(name, p, bool)
 484
 485 /* An int, which can only be set like a bool (though it shows as an int). */
 486 extern const struct kernel_param_ops param_ops_bint;
 487 extern int param_set_bint(const char *val, const struct kernel_param *kp);
 488 #define param_get_bint param_get_int
 489 #define param_check_bint param_check_int
 490
 491 /**
 492  * module_param_array - a parameter which is an array of some type
 493  * @name: the name of the array variable
 494  * @type: the type, as per module_param()
 495  * @nump: optional pointer filled in with the number written
 496  * @perm: visibility in sysfs
 497  *
 498  * Input and output are as comma-separated values.  Commas inside values
 499  * don't work properly (eg. an array of charp).
 500  *
 501  * ARRAY_SIZE(@name) is used to determine the number of elements in the
 502  * array, so the definition must be visible.
 503  */
 504 #define module_param_array(name, type, nump, perm)              \
 505         module_param_array_named(name, name, type, nump, perm)
 506
 507 /**
 508  * module_param_array_named - renamed parameter which is an array of some type
 509  * @name: a valid C identifier which is the parameter name
 510  * @array: the name of the array variable
 511  * @type: the type, as per module_param()
 512  * @nump: optional pointer filled in with the number written
 513  * @perm: visibility in sysfs
 514  *
 515  * This exposes a different name than the actual variable name.  See
 516  * module_param_named() for why this might be necessary.
 517  */
 518 #define module_param_array_named(name, array, type, nump, perm)         \
 519         param_check_##type(name, &(array)[0]);                          \
 520         static const struct kparam_array __param_arr_##name             \
 521         = { .max = ARRAY_SIZE(array), .num = nump,                      \
 522             .ops = &param_ops_##type,                                   \
 523             .elemsize = sizeof(array[0]), .elem = array };              \
 524         __module_param_call(MODULE_PARAM_PREFIX, name,                  \
 525                             &param_array_ops,                           \
 526                             .arr = &__param_arr_##name,                 \
 527                             perm, -1, 0);                               \
 528         __MODULE_PARM_TYPE(name, "array of " #type)
 529
 530 enum hwparam_type {
 531         hwparam_ioport,         /* Module parameter configures an I/O port */
 532         hwparam_iomem,          /* Module parameter configures an I/O mem address */
 533         hwparam_ioport_or_iomem, /* Module parameter could be either, depending on other option */
 534         hwparam_irq,            /* Module parameter configures an IRQ */
 535         hwparam_dma,            /* Module parameter configures a DMA channel */
 536         hwparam_dma_addr,       /* Module parameter configures a DMA buffer address */
 537         hwparam_other,          /* Module parameter configures some other value */
 538 };
 539
 540 /**
 541  * module_param_hw_named - A parameter representing a hw parameters
 542  * @name: a valid C identifier which is the parameter name.
 543  * @value: the actual lvalue to alter.
 544  * @type: the type of the parameter
 545  * @hwtype: what the value represents (enum hwparam_type)
 546  * @perm: visibility in sysfs.
 547  *
 548  * Usually it's a good idea to have variable names and user-exposed names the
 549  * same, but that's harder if the variable must be non-static or is inside a
 550  * structure.  This allows exposure under a different name.
 551  */
 552 #define module_param_hw_named(name, value, type, hwtype, perm)          \
 553         param_check_##type(name, &(value));                             \
 554         __module_param_call(MODULE_PARAM_PREFIX, name,                  \
 555                             &param_ops_##type, &value,                  \
 556                             perm, -1,                                   \
 557                             KERNEL_PARAM_FL_HWPARAM | (hwparam_##hwtype & 0));  \
 558         __MODULE_PARM_TYPE(name, #type)
 559
 560 #define module_param_hw(name, type, hwtype, perm)               \
 561         module_param_hw_named(name, name, type, hwtype, perm)
 562
 563 /**
 564  * module_param_hw_array - A parameter representing an array of hw parameters
 565  * @name: the name of the array variable
 566  * @type: the type, as per module_param()
 567  * @hwtype: what the value represents (enum hwparam_type)
 568  * @nump: optional pointer filled in with the number written
 569  * @perm: visibility in sysfs
 570  *
 571  * Input and output are as comma-separated values.  Commas inside values
 572  * don't work properly (eg. an array of charp).
 573  *
 574  * ARRAY_SIZE(@name) is used to determine the number of elements in the
 575  * array, so the definition must be visible.
 576  */
 577 #define module_param_hw_array(name, type, hwtype, nump, perm)           \
 578         param_check_##type(name, &(name)[0]);                           \
 579         static const struct kparam_array __param_arr_##name             \
 580         = { .max = ARRAY_SIZE(name), .num = nump,                       \
 581             .ops = &param_ops_##type,                                   \
 582             .elemsize = sizeof(name[0]), .elem = name };                \
 583         __module_param_call(MODULE_PARAM_PREFIX, name,                  \
 584                             &param_array_ops,                           \
 585                             .arr = &__param_arr_##name,                 \
 586                             perm, -1,                                   \
 587                             KERNEL_PARAM_FL_HWPARAM | (hwparam_##hwtype & 0));  \
 588         __MODULE_PARM_TYPE(name, "array of " #type)
 589
 590
 591 extern const struct kernel_param_ops param_array_ops;
 592
 593 extern const struct kernel_param_ops param_ops_string;
 594 extern int param_set_copystring(const char *val, const struct kernel_param *);
 595 extern int param_get_string(char *buffer, const struct kernel_param *kp);
 596
 597 /* for exporting parameters in /sys/module/.../parameters */
 598
 599 struct module;
 600
 601 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES)
 602 extern int module_param_sysfs_setup(struct module *mod,
 603                                     const struct kernel_param *kparam,
 604                                     unsigned int num_params);
 605
 606 extern void module_param_sysfs_remove(struct module *mod);
 607 #else
 608 static inline int module_param_sysfs_setup(struct module *mod,
 609                              const struct kernel_param *kparam,
 610                              unsigned int num_params)
 611 {
 612         return 0;
 613 }
 614
 615 static inline void module_param_sysfs_remove(struct module *mod)
 616 { }
 617 #endif
 618
 619 #endif /* _LINUX_MODULE_PARAMS_H */