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