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
36struct 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 */
43enum {
44 KERNEL_PARAM_OPS_FL_NOARG = (1 << 0)
45};
46
47struct 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 */
64enum {
65 KERNEL_PARAM_FL_UNSAFE = (1 << 0),
66 KERNEL_PARAM_FL_HWPARAM = (1 << 1),
67};
68
69struct 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
83extern const struct kernel_param __start___param[], __stop___param[];
84
85/* Special one for strings we want to copy into */
86struct kparam_string {
87 unsigned int maxlen;
88 char *string;
89};
90
91/* Special one for arrays */
92struct 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_IA64) || 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/* Obsolete - use module_param_cb() */
297#define module_param_call(name, _set, _get, arg, perm) \
298 static const struct kernel_param_ops __param_ops_##name = \
299 { .flags = 0, .set = _set, .get = _get }; \
300 __module_param_call(MODULE_PARAM_PREFIX, \
301 name, &__param_ops_##name, arg, perm, -1, 0)
302
303#ifdef CONFIG_SYSFS
304extern void kernel_param_lock(struct module *mod);
305extern void kernel_param_unlock(struct module *mod);
306#else
307static inline void kernel_param_lock(struct module *mod)
308{
309}
310static inline void kernel_param_unlock(struct module *mod)
311{
312}
313#endif
314
315#ifndef MODULE
316/**
317 * core_param - define a historical core kernel parameter.
318 * @name: the name of the cmdline and sysfs parameter (often the same as var)
319 * @var: the variable
320 * @type: the type of the parameter
321 * @perm: visibility in sysfs
322 *
323 * core_param is just like module_param(), but cannot be modular and
324 * doesn't add a prefix (such as "printk."). This is for compatibility
325 * with __setup(), and it makes sense as truly core parameters aren't
326 * tied to the particular file they're in.
327 */
328#define core_param(name, var, type, perm) \
329 param_check_##type(name, &(var)); \
330 __module_param_call("", name, &param_ops_##type, &var, perm, -1, 0)
331
332/**
333 * core_param_unsafe - same as core_param but taints kernel
334 * @name: the name of the cmdline and sysfs parameter (often the same as var)
335 * @var: the variable
336 * @type: the type of the parameter
337 * @perm: visibility in sysfs
338 */
339#define core_param_unsafe(name, var, type, perm) \
340 param_check_##type(name, &(var)); \
341 __module_param_call("", name, &param_ops_##type, &var, perm, \
342 -1, KERNEL_PARAM_FL_UNSAFE)
343
344#endif /* !MODULE */
345
346/**
347 * module_param_string - a char array parameter
348 * @name: the name of the parameter
349 * @string: the string variable
350 * @len: the maximum length of the string, incl. terminator
351 * @perm: visibility in sysfs.
352 *
353 * This actually copies the string when it's set (unlike type charp).
354 * @len is usually just sizeof(string).
355 */
356#define module_param_string(name, string, len, perm) \
357 static const struct kparam_string __param_string_##name \
358 = { len, string }; \
359 __module_param_call(MODULE_PARAM_PREFIX, name, \
360 &param_ops_string, \
361 .str = &__param_string_##name, perm, -1, 0);\
362 __MODULE_PARM_TYPE(name, "string")
363
364/**
365 * parameq - checks if two parameter names match
366 * @name1: parameter name 1
367 * @name2: parameter name 2
368 *
369 * Returns true if the two parameter names are equal.
370 * Dashes (-) are considered equal to underscores (_).
371 */
372extern bool parameq(const char *name1, const char *name2);
373
374/**
375 * parameqn - checks if two parameter names match
376 * @name1: parameter name 1
377 * @name2: parameter name 2
378 * @n: the length to compare
379 *
380 * Similar to parameq(), except it compares @n characters.
381 */
382extern bool parameqn(const char *name1, const char *name2, size_t n);
383
384/* Called on module insert or kernel boot */
385extern char *parse_args(const char *name,
386 char *args,
387 const struct kernel_param *params,
388 unsigned num,
389 s16 level_min,
390 s16 level_max,
391 void *arg,
392 int (*unknown)(char *param, char *val,
393 const char *doing, void *arg));
394
395/* Called by module remove. */
396#ifdef CONFIG_SYSFS
397extern void destroy_params(const struct kernel_param *params, unsigned num);
398#else
399static inline void destroy_params(const struct kernel_param *params,
400 unsigned num)
401{
402}
403#endif /* !CONFIG_SYSFS */
404
405/* All the helper functions */
406/* The macros to do compile-time type checking stolen from Jakub
407 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */
408#define __param_check(name, p, type) \
409 static inline type __always_unused *__check_##name(void) { return(p); }
410
411extern const struct kernel_param_ops param_ops_byte;
412extern int param_set_byte(const char *val, const struct kernel_param *kp);
413extern int param_get_byte(char *buffer, const struct kernel_param *kp);
414#define param_check_byte(name, p) __param_check(name, p, unsigned char)
415
416extern const struct kernel_param_ops param_ops_short;
417extern int param_set_short(const char *val, const struct kernel_param *kp);
418extern int param_get_short(char *buffer, const struct kernel_param *kp);
419#define param_check_short(name, p) __param_check(name, p, short)
420
421extern const struct kernel_param_ops param_ops_ushort;
422extern int param_set_ushort(const char *val, const struct kernel_param *kp);
423extern int param_get_ushort(char *buffer, const struct kernel_param *kp);
424#define param_check_ushort(name, p) __param_check(name, p, unsigned short)
425
426extern const struct kernel_param_ops param_ops_int;
427extern int param_set_int(const char *val, const struct kernel_param *kp);
428extern int param_get_int(char *buffer, const struct kernel_param *kp);
429#define param_check_int(name, p) __param_check(name, p, int)
430
431extern const struct kernel_param_ops param_ops_uint;
432extern int param_set_uint(const char *val, const struct kernel_param *kp);
433extern int param_get_uint(char *buffer, const struct kernel_param *kp);
434int param_set_uint_minmax(const char *val, const struct kernel_param *kp,
435 unsigned int min, unsigned int max);
436#define param_check_uint(name, p) __param_check(name, p, unsigned int)
437
438extern const struct kernel_param_ops param_ops_long;
439extern int param_set_long(const char *val, const struct kernel_param *kp);
440extern int param_get_long(char *buffer, const struct kernel_param *kp);
441#define param_check_long(name, p) __param_check(name, p, long)
442
443extern const struct kernel_param_ops param_ops_ulong;
444extern int param_set_ulong(const char *val, const struct kernel_param *kp);
445extern int param_get_ulong(char *buffer, const struct kernel_param *kp);
446#define param_check_ulong(name, p) __param_check(name, p, unsigned long)
447
448extern const struct kernel_param_ops param_ops_ullong;
449extern int param_set_ullong(const char *val, const struct kernel_param *kp);
450extern int param_get_ullong(char *buffer, const struct kernel_param *kp);
451#define param_check_ullong(name, p) __param_check(name, p, unsigned long long)
452
453extern const struct kernel_param_ops param_ops_hexint;
454extern int param_set_hexint(const char *val, const struct kernel_param *kp);
455extern int param_get_hexint(char *buffer, const struct kernel_param *kp);
456#define param_check_hexint(name, p) param_check_uint(name, p)
457
458extern const struct kernel_param_ops param_ops_charp;
459extern int param_set_charp(const char *val, const struct kernel_param *kp);
460extern int param_get_charp(char *buffer, const struct kernel_param *kp);
461extern void param_free_charp(void *arg);
462#define param_check_charp(name, p) __param_check(name, p, char *)
463
464/* We used to allow int as well as bool. We're taking that away! */
465extern const struct kernel_param_ops param_ops_bool;
466extern int param_set_bool(const char *val, const struct kernel_param *kp);
467extern int param_get_bool(char *buffer, const struct kernel_param *kp);
468#define param_check_bool(name, p) __param_check(name, p, bool)
469
470extern const struct kernel_param_ops param_ops_bool_enable_only;
471extern int param_set_bool_enable_only(const char *val,
472 const struct kernel_param *kp);
473/* getter is the same as for the regular bool */
474#define param_check_bool_enable_only param_check_bool
475
476extern const struct kernel_param_ops param_ops_invbool;
477extern int param_set_invbool(const char *val, const struct kernel_param *kp);
478extern int param_get_invbool(char *buffer, const struct kernel_param *kp);
479#define param_check_invbool(name, p) __param_check(name, p, bool)
480
481/* An int, which can only be set like a bool (though it shows as an int). */
482extern const struct kernel_param_ops param_ops_bint;
483extern int param_set_bint(const char *val, const struct kernel_param *kp);
484#define param_get_bint param_get_int
485#define param_check_bint param_check_int
486
487/**
488 * module_param_array - a parameter which is an array of some type
489 * @name: the name of the array variable
490 * @type: the type, as per module_param()
491 * @nump: optional pointer filled in with the number written
492 * @perm: visibility in sysfs
493 *
494 * Input and output are as comma-separated values. Commas inside values
495 * don't work properly (eg. an array of charp).
496 *
497 * ARRAY_SIZE(@name) is used to determine the number of elements in the
498 * array, so the definition must be visible.
499 */
500#define module_param_array(name, type, nump, perm) \
501 module_param_array_named(name, name, type, nump, perm)
502
503/**
504 * module_param_array_named - renamed parameter which is an array of some type
505 * @name: a valid C identifier which is the parameter name
506 * @array: the name of the array variable
507 * @type: the type, as per module_param()
508 * @nump: optional pointer filled in with the number written
509 * @perm: visibility in sysfs
510 *
511 * This exposes a different name than the actual variable name. See
512 * module_param_named() for why this might be necessary.
513 */
514#define module_param_array_named(name, array, type, nump, perm) \
515 param_check_##type(name, &(array)[0]); \
516 static const struct kparam_array __param_arr_##name \
517 = { .max = ARRAY_SIZE(array), .num = nump, \
518 .ops = &param_ops_##type, \
519 .elemsize = sizeof(array[0]), .elem = array }; \
520 __module_param_call(MODULE_PARAM_PREFIX, name, \
521 &param_array_ops, \
522 .arr = &__param_arr_##name, \
523 perm, -1, 0); \
524 __MODULE_PARM_TYPE(name, "array of " #type)
525
526enum hwparam_type {
527 hwparam_ioport, /* Module parameter configures an I/O port */
528 hwparam_iomem, /* Module parameter configures an I/O mem address */
529 hwparam_ioport_or_iomem, /* Module parameter could be either, depending on other option */
530 hwparam_irq, /* Module parameter configures an IRQ */
531 hwparam_dma, /* Module parameter configures a DMA channel */
532 hwparam_dma_addr, /* Module parameter configures a DMA buffer address */
533 hwparam_other, /* Module parameter configures some other value */
534};
535
536/**
537 * module_param_hw_named - A parameter representing a hw parameters
538 * @name: a valid C identifier which is the parameter name.
539 * @value: the actual lvalue to alter.
540 * @type: the type of the parameter
541 * @hwtype: what the value represents (enum hwparam_type)
542 * @perm: visibility in sysfs.
543 *
544 * Usually it's a good idea to have variable names and user-exposed names the
545 * same, but that's harder if the variable must be non-static or is inside a
546 * structure. This allows exposure under a different name.
547 */
548#define module_param_hw_named(name, value, type, hwtype, perm) \
549 param_check_##type(name, &(value)); \
550 __module_param_call(MODULE_PARAM_PREFIX, name, \
551 &param_ops_##type, &value, \
552 perm, -1, \
553 KERNEL_PARAM_FL_HWPARAM | (hwparam_##hwtype & 0)); \
554 __MODULE_PARM_TYPE(name, #type)
555
556#define module_param_hw(name, type, hwtype, perm) \
557 module_param_hw_named(name, name, type, hwtype, perm)
558
559/**
560 * module_param_hw_array - A parameter representing an array of hw parameters
561 * @name: the name of the array variable
562 * @type: the type, as per module_param()
563 * @hwtype: what the value represents (enum hwparam_type)
564 * @nump: optional pointer filled in with the number written
565 * @perm: visibility in sysfs
566 *
567 * Input and output are as comma-separated values. Commas inside values
568 * don't work properly (eg. an array of charp).
569 *
570 * ARRAY_SIZE(@name) is used to determine the number of elements in the
571 * array, so the definition must be visible.
572 */
573#define module_param_hw_array(name, type, hwtype, nump, perm) \
574 param_check_##type(name, &(name)[0]); \
575 static const struct kparam_array __param_arr_##name \
576 = { .max = ARRAY_SIZE(name), .num = nump, \
577 .ops = &param_ops_##type, \
578 .elemsize = sizeof(name[0]), .elem = name }; \
579 __module_param_call(MODULE_PARAM_PREFIX, name, \
580 &param_array_ops, \
581 .arr = &__param_arr_##name, \
582 perm, -1, \
583 KERNEL_PARAM_FL_HWPARAM | (hwparam_##hwtype & 0)); \
584 __MODULE_PARM_TYPE(name, "array of " #type)
585
586
587extern const struct kernel_param_ops param_array_ops;
588
589extern const struct kernel_param_ops param_ops_string;
590extern int param_set_copystring(const char *val, const struct kernel_param *);
591extern int param_get_string(char *buffer, const struct kernel_param *kp);
592
593/* for exporting parameters in /sys/module/.../parameters */
594
595struct module;
596
597#if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES)
598extern int module_param_sysfs_setup(struct module *mod,
599 const struct kernel_param *kparam,
600 unsigned int num_params);
601
602extern void module_param_sysfs_remove(struct module *mod);
603#else
604static inline int module_param_sysfs_setup(struct module *mod,
605 const struct kernel_param *kparam,
606 unsigned int num_params)
607{
608 return 0;
609}
610
611static inline void module_param_sysfs_remove(struct module *mod)
612{ }
613#endif
614
615#endif /* _LINUX_MODULE_PARAMS_H */
616

source code of linux/include/linux/moduleparam.h