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 #else
14 #define MODULE_PARAM_PREFIX KBUILD_MODNAME "."
15 #endif
16
17 /* Chosen so that structs with an unsigned long line up. */
18 #define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long))
19
20 #ifdef MODULE
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
25 #else /* !MODULE */
26 /* This struct is here for syntactic coherency, it is not used */
27 #define __MODULE_INFO(tag, name, info) \
28 struct __UNIQUE_ID(name) {}
29 #endif
30 #define __MODULE_PARM_TYPE(name, _type) \
31 __MODULE_INFO(parmtype, name##type, #name ":" _type)
32
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)
37
38 struct kernel_param;
39
40 /*
41 * Flags available for kernel_param_ops
42 *
43 * NOARG - the parameter allows for no argument (foo instead of foo=1)
44 */
45 enum {
46 KERNEL_PARAM_OPS_FL_NOARG = (1 << 0)
47 };
48
49 struct kernel_param_ops {
50 /* How the ops should behave */
51 unsigned int flags;
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);
58 };
59
60 /*
61 * Flags available for kernel_param
62 *
63 * UNSAFE - the parameter is dangerous and setting it will taint the kernel
64 * HWPARAM - Hardware param not permitted in lockdown mode
65 */
66 enum {
67 KERNEL_PARAM_FL_UNSAFE = (1 << 0),
68 KERNEL_PARAM_FL_HWPARAM = (1 << 1),
69 };
70
71 struct kernel_param {
72 const char *name;
73 struct module *mod;
74 const struct kernel_param_ops *ops;
75 const u16 perm;
76 s8 level;
77 u8 flags;
78 union {
79 void *arg;
80 const struct kparam_string *str;
81 const struct kparam_array *arr;
82 };
83 };
84
85 extern const struct kernel_param __start___param[], __stop___param[];
86
87 /* Special one for strings we want to copy into */
88 struct kparam_string {
89 unsigned int maxlen;
90 char *string;
91 };
92
93 /* Special one for arrays */
94 struct kparam_array
95 {
96 unsigned int max;
97 unsigned int elemsize;
98 unsigned int *num;
99 const struct kernel_param_ops *ops;
100 void *elem;
101 };
102
103 /**
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.
108 *
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".
112 *
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).
117 *
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.
121 *
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).
127 */
128 #define module_param(name, type, perm) \
129 module_param_named(name, name, type, perm)
130
131 /**
132 * module_param_unsafe - same as module_param but taints kernel
133 */
134 #define module_param_unsafe(name, type, perm) \
135 module_param_named_unsafe(name, name, type, perm)
136
137 /**
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.
143 *
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.
147 */
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)
152
153 /**
154 * module_param_named_unsafe - same as module_param_named but taints kernel
155 */
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)
160
161 /**
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.
166 *
167 * The ops can have NULL set or get functions.
168 */
169 #define module_param_cb(name, ops, arg, perm) \
170 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, 0)
171
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)
175
176 /**
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.
182 *
183 * The ops can have NULL set or get functions.
184 */
185 #define __level_param_cb(name, ops, arg, perm, level) \
186 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level, 0)
187
188 #define core_param_cb(name, ops, arg, perm) \
189 __level_param_cb(name, ops, arg, perm, 1)
190
191 #define postcore_param_cb(name, ops, arg, perm) \
192 __level_param_cb(name, ops, arg, perm, 2)
193
194 #define arch_param_cb(name, ops, arg, perm) \
195 __level_param_cb(name, ops, arg, perm, 3)
196
197 #define subsys_param_cb(name, ops, arg, perm) \
198 __level_param_cb(name, ops, arg, perm, 4)
199
200 #define fs_param_cb(name, ops, arg, perm) \
201 __level_param_cb(name, ops, arg, perm, 5)
202
203 #define device_param_cb(name, ops, arg, perm) \
204 __level_param_cb(name, ops, arg, perm, 6)
205
206 #define late_param_cb(name, ops, arg, perm) \
207 __level_param_cb(name, ops, arg, perm, 7)
208
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
215 #else
216 #define __moduleparam_const const
217 #endif
218
219 /* This is the fundamental function for registering boot/module
220 parameters. */
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 \
225 __used \
226 __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
227 = { __param_str_##name, THIS_MODULE, ops, \
228 VERIFY_OCTAL_PERMISSIONS(perm), level, flags, { arg } }
229
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, .set = _set, .get = _get }; \
234 __module_param_call(MODULE_PARAM_PREFIX, \
235 name, &__param_ops_##name, arg, perm, -1, 0)
236
237 #ifdef CONFIG_SYSFS
238 extern void kernel_param_lock(struct module *mod);
239 extern void kernel_param_unlock(struct module *mod);
240 #else
kernel_param_lock(struct module * mod)241 static inline void kernel_param_lock(struct module *mod)
242 {
243 }
kernel_param_unlock(struct module * mod)244 static inline void kernel_param_unlock(struct module *mod)
245 {
246 }
247 #endif
248
249 #ifndef MODULE
250 /**
251 * core_param - define a historical core kernel parameter.
252 * @name: the name of the cmdline and sysfs parameter (often the same as var)
253 * @var: the variable
254 * @type: the type of the parameter
255 * @perm: visibility in sysfs
256 *
257 * core_param is just like module_param(), but cannot be modular and
258 * doesn't add a prefix (such as "printk."). This is for compatibility
259 * with __setup(), and it makes sense as truly core parameters aren't
260 * tied to the particular file they're in.
261 */
262 #define core_param(name, var, type, perm) \
263 param_check_##type(name, &(var)); \
264 __module_param_call("", name, ¶m_ops_##type, &var, perm, -1, 0)
265
266 /**
267 * core_param_unsafe - same as core_param but taints kernel
268 */
269 #define core_param_unsafe(name, var, type, perm) \
270 param_check_##type(name, &(var)); \
271 __module_param_call("", name, ¶m_ops_##type, &var, perm, \
272 -1, KERNEL_PARAM_FL_UNSAFE)
273
274 #endif /* !MODULE */
275
276 /**
277 * module_param_string - a char array parameter
278 * @name: the name of the parameter
279 * @string: the string variable
280 * @len: the maximum length of the string, incl. terminator
281 * @perm: visibility in sysfs.
282 *
283 * This actually copies the string when it's set (unlike type charp).
284 * @len is usually just sizeof(string).
285 */
286 #define module_param_string(name, string, len, perm) \
287 static const struct kparam_string __param_string_##name \
288 = { len, string }; \
289 __module_param_call(MODULE_PARAM_PREFIX, name, \
290 ¶m_ops_string, \
291 .str = &__param_string_##name, perm, -1, 0);\
292 __MODULE_PARM_TYPE(name, "string")
293
294 /**
295 * parameq - checks if two parameter names match
296 * @name1: parameter name 1
297 * @name2: parameter name 2
298 *
299 * Returns true if the two parameter names are equal.
300 * Dashes (-) are considered equal to underscores (_).
301 */
302 extern bool parameq(const char *name1, const char *name2);
303
304 /**
305 * parameqn - checks if two parameter names match
306 * @name1: parameter name 1
307 * @name2: parameter name 2
308 * @n: the length to compare
309 *
310 * Similar to parameq(), except it compares @n characters.
311 */
312 extern bool parameqn(const char *name1, const char *name2, size_t n);
313
314 /* Called on module insert or kernel boot */
315 extern char *parse_args(const char *name,
316 char *args,
317 const struct kernel_param *params,
318 unsigned num,
319 s16 level_min,
320 s16 level_max,
321 void *arg,
322 int (*unknown)(char *param, char *val,
323 const char *doing, void *arg));
324
325 /* Called by module remove. */
326 #ifdef CONFIG_SYSFS
327 extern void destroy_params(const struct kernel_param *params, unsigned num);
328 #else
destroy_params(const struct kernel_param * params,unsigned num)329 static inline void destroy_params(const struct kernel_param *params,
330 unsigned num)
331 {
332 }
333 #endif /* !CONFIG_SYSFS */
334
335 /* All the helper functions */
336 /* The macros to do compile-time type checking stolen from Jakub
337 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */
338 #define __param_check(name, p, type) \
339 static inline type __always_unused *__check_##name(void) { return(p); }
340
341 extern const struct kernel_param_ops param_ops_byte;
342 extern int param_set_byte(const char *val, const struct kernel_param *kp);
343 extern int param_get_byte(char *buffer, const struct kernel_param *kp);
344 #define param_check_byte(name, p) __param_check(name, p, unsigned char)
345
346 extern const struct kernel_param_ops param_ops_short;
347 extern int param_set_short(const char *val, const struct kernel_param *kp);
348 extern int param_get_short(char *buffer, const struct kernel_param *kp);
349 #define param_check_short(name, p) __param_check(name, p, short)
350
351 extern const struct kernel_param_ops param_ops_ushort;
352 extern int param_set_ushort(const char *val, const struct kernel_param *kp);
353 extern int param_get_ushort(char *buffer, const struct kernel_param *kp);
354 #define param_check_ushort(name, p) __param_check(name, p, unsigned short)
355
356 extern const struct kernel_param_ops param_ops_int;
357 extern int param_set_int(const char *val, const struct kernel_param *kp);
358 extern int param_get_int(char *buffer, const struct kernel_param *kp);
359 #define param_check_int(name, p) __param_check(name, p, int)
360
361 extern const struct kernel_param_ops param_ops_uint;
362 extern int param_set_uint(const char *val, const struct kernel_param *kp);
363 extern int param_get_uint(char *buffer, const struct kernel_param *kp);
364 #define param_check_uint(name, p) __param_check(name, p, unsigned int)
365
366 extern const struct kernel_param_ops param_ops_long;
367 extern int param_set_long(const char *val, const struct kernel_param *kp);
368 extern int param_get_long(char *buffer, const struct kernel_param *kp);
369 #define param_check_long(name, p) __param_check(name, p, long)
370
371 extern const struct kernel_param_ops param_ops_ulong;
372 extern int param_set_ulong(const char *val, const struct kernel_param *kp);
373 extern int param_get_ulong(char *buffer, const struct kernel_param *kp);
374 #define param_check_ulong(name, p) __param_check(name, p, unsigned long)
375
376 extern const struct kernel_param_ops param_ops_ullong;
377 extern int param_set_ullong(const char *val, const struct kernel_param *kp);
378 extern int param_get_ullong(char *buffer, const struct kernel_param *kp);
379 #define param_check_ullong(name, p) __param_check(name, p, unsigned long long)
380
381 extern const struct kernel_param_ops param_ops_charp;
382 extern int param_set_charp(const char *val, const struct kernel_param *kp);
383 extern int param_get_charp(char *buffer, const struct kernel_param *kp);
384 extern void param_free_charp(void *arg);
385 #define param_check_charp(name, p) __param_check(name, p, char *)
386
387 /* We used to allow int as well as bool. We're taking that away! */
388 extern const struct kernel_param_ops param_ops_bool;
389 extern int param_set_bool(const char *val, const struct kernel_param *kp);
390 extern int param_get_bool(char *buffer, const struct kernel_param *kp);
391 #define param_check_bool(name, p) __param_check(name, p, bool)
392
393 extern const struct kernel_param_ops param_ops_bool_enable_only;
394 extern int param_set_bool_enable_only(const char *val,
395 const struct kernel_param *kp);
396 /* getter is the same as for the regular bool */
397 #define param_check_bool_enable_only param_check_bool
398
399 extern const struct kernel_param_ops param_ops_invbool;
400 extern int param_set_invbool(const char *val, const struct kernel_param *kp);
401 extern int param_get_invbool(char *buffer, const struct kernel_param *kp);
402 #define param_check_invbool(name, p) __param_check(name, p, bool)
403
404 /* An int, which can only be set like a bool (though it shows as an int). */
405 extern const struct kernel_param_ops param_ops_bint;
406 extern int param_set_bint(const char *val, const struct kernel_param *kp);
407 #define param_get_bint param_get_int
408 #define param_check_bint param_check_int
409
410 /**
411 * module_param_array - a parameter which is an array of some type
412 * @name: the name of the array variable
413 * @type: the type, as per module_param()
414 * @nump: optional pointer filled in with the number written
415 * @perm: visibility in sysfs
416 *
417 * Input and output are as comma-separated values. Commas inside values
418 * don't work properly (eg. an array of charp).
419 *
420 * ARRAY_SIZE(@name) is used to determine the number of elements in the
421 * array, so the definition must be visible.
422 */
423 #define module_param_array(name, type, nump, perm) \
424 module_param_array_named(name, name, type, nump, perm)
425
426 /**
427 * module_param_array_named - renamed parameter which is an array of some type
428 * @name: a valid C identifier which is the parameter name
429 * @array: the name of the array variable
430 * @type: the type, as per module_param()
431 * @nump: optional pointer filled in with the number written
432 * @perm: visibility in sysfs
433 *
434 * This exposes a different name than the actual variable name. See
435 * module_param_named() for why this might be necessary.
436 */
437 #define module_param_array_named(name, array, type, nump, perm) \
438 param_check_##type(name, &(array)[0]); \
439 static const struct kparam_array __param_arr_##name \
440 = { .max = ARRAY_SIZE(array), .num = nump, \
441 .ops = ¶m_ops_##type, \
442 .elemsize = sizeof(array[0]), .elem = array }; \
443 __module_param_call(MODULE_PARAM_PREFIX, name, \
444 ¶m_array_ops, \
445 .arr = &__param_arr_##name, \
446 perm, -1, 0); \
447 __MODULE_PARM_TYPE(name, "array of " #type)
448
449 enum hwparam_type {
450 hwparam_ioport, /* Module parameter configures an I/O port */
451 hwparam_iomem, /* Module parameter configures an I/O mem address */
452 hwparam_ioport_or_iomem, /* Module parameter could be either, depending on other option */
453 hwparam_irq, /* Module parameter configures an IRQ */
454 hwparam_dma, /* Module parameter configures a DMA channel */
455 hwparam_dma_addr, /* Module parameter configures a DMA buffer address */
456 hwparam_other, /* Module parameter configures some other value */
457 };
458
459 /**
460 * module_param_hw_named - A parameter representing a hw parameters
461 * @name: a valid C identifier which is the parameter name.
462 * @value: the actual lvalue to alter.
463 * @type: the type of the parameter
464 * @hwtype: what the value represents (enum hwparam_type)
465 * @perm: visibility in sysfs.
466 *
467 * Usually it's a good idea to have variable names and user-exposed names the
468 * same, but that's harder if the variable must be non-static or is inside a
469 * structure. This allows exposure under a different name.
470 */
471 #define module_param_hw_named(name, value, type, hwtype, perm) \
472 param_check_##type(name, &(value)); \
473 __module_param_call(MODULE_PARAM_PREFIX, name, \
474 ¶m_ops_##type, &value, \
475 perm, -1, \
476 KERNEL_PARAM_FL_HWPARAM | (hwparam_##hwtype & 0)); \
477 __MODULE_PARM_TYPE(name, #type)
478
479 #define module_param_hw(name, type, hwtype, perm) \
480 module_param_hw_named(name, name, type, hwtype, perm)
481
482 /**
483 * module_param_hw_array - A parameter representing an array of hw parameters
484 * @name: the name of the array variable
485 * @type: the type, as per module_param()
486 * @hwtype: what the value represents (enum hwparam_type)
487 * @nump: optional pointer filled in with the number written
488 * @perm: visibility in sysfs
489 *
490 * Input and output are as comma-separated values. Commas inside values
491 * don't work properly (eg. an array of charp).
492 *
493 * ARRAY_SIZE(@name) is used to determine the number of elements in the
494 * array, so the definition must be visible.
495 */
496 #define module_param_hw_array(name, type, hwtype, nump, perm) \
497 param_check_##type(name, &(name)[0]); \
498 static const struct kparam_array __param_arr_##name \
499 = { .max = ARRAY_SIZE(name), .num = nump, \
500 .ops = ¶m_ops_##type, \
501 .elemsize = sizeof(name[0]), .elem = name }; \
502 __module_param_call(MODULE_PARAM_PREFIX, name, \
503 ¶m_array_ops, \
504 .arr = &__param_arr_##name, \
505 perm, -1, \
506 KERNEL_PARAM_FL_HWPARAM | (hwparam_##hwtype & 0)); \
507 __MODULE_PARM_TYPE(name, "array of " #type)
508
509
510 extern const struct kernel_param_ops param_array_ops;
511
512 extern const struct kernel_param_ops param_ops_string;
513 extern int param_set_copystring(const char *val, const struct kernel_param *);
514 extern int param_get_string(char *buffer, const struct kernel_param *kp);
515
516 /* for exporting parameters in /sys/module/.../parameters */
517
518 struct module;
519
520 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES)
521 extern int module_param_sysfs_setup(struct module *mod,
522 const struct kernel_param *kparam,
523 unsigned int num_params);
524
525 extern void module_param_sysfs_remove(struct module *mod);
526 #else
module_param_sysfs_setup(struct module * mod,const struct kernel_param * kparam,unsigned int num_params)527 static inline int module_param_sysfs_setup(struct module *mod,
528 const struct kernel_param *kparam,
529 unsigned int num_params)
530 {
531 return 0;
532 }
533
module_param_sysfs_remove(struct module * mod)534 static inline void module_param_sysfs_remove(struct module *mod)
535 { }
536 #endif
537
538 #endif /* _LINUX_MODULE_PARAMS_H */
539