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 __attribute__((section(".modinfo"), unused, 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 * @value: the variable to alter, and exposed parameter name.
104 * @type: the type of the parameter
105 * @perm: visibility in sysfs.
106 *
107 * @value 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 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, 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 */
132 #define module_param_unsafe(name, type, perm) \
133 module_param_named_unsafe(name, name, type, perm)
134
135 /**
136 * module_param_named - typesafe helper for a renamed module/cmdline parameter
137 * @name: a valid C identifier which is the parameter name.
138 * @value: the actual lvalue to alter.
139 * @type: the type of the parameter
140 * @perm: visibility in sysfs.
141 *
142 * Usually it's a good idea to have variable names and user-exposed names the
143 * same, but that's harder if the variable must be non-static or is inside a
144 * structure. This allows exposure under a different name.
145 */
146 #define module_param_named(name, value, type, perm) \
147 param_check_##type(name, &(value)); \
148 module_param_cb(name, ¶m_ops_##type, &value, perm); \
149 __MODULE_PARM_TYPE(name, #type)
150
151 /**
152 * module_param_named_unsafe - same as module_param_named but taints kernel
153 */
154 #define module_param_named_unsafe(name, value, type, perm) \
155 param_check_##type(name, &(value)); \
156 module_param_cb_unsafe(name, ¶m_ops_##type, &value, perm); \
157 __MODULE_PARM_TYPE(name, #type)
158
159 /**
160 * module_param_cb - general callback for a module/cmdline parameter
161 * @name: a valid C identifier which is the parameter name.
162 * @ops: the set & get operations for this parameter.
163 * @perm: visibility in sysfs.
164 *
165 * The ops can have NULL set or get functions.
166 */
167 #define module_param_cb(name, ops, arg, perm) \
168 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, 0)
169
170 #define module_param_cb_unsafe(name, ops, arg, perm) \
171 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, \
172 KERNEL_PARAM_FL_UNSAFE)
173
174 /**
175 * <level>_param_cb - general callback for a module/cmdline parameter
176 * to be evaluated before certain initcall level
177 * @name: a valid C identifier which is the parameter name.
178 * @ops: the set & get operations for this parameter.
179 * @perm: visibility in sysfs.
180 *
181 * The ops can have NULL set or get functions.
182 */
183 #define __level_param_cb(name, ops, arg, perm, level) \
184 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level, 0)
185
186 #define core_param_cb(name, ops, arg, perm) \
187 __level_param_cb(name, ops, arg, perm, 1)
188
189 #define postcore_param_cb(name, ops, arg, perm) \
190 __level_param_cb(name, ops, arg, perm, 2)
191
192 #define arch_param_cb(name, ops, arg, perm) \
193 __level_param_cb(name, ops, arg, perm, 3)
194
195 #define subsys_param_cb(name, ops, arg, perm) \
196 __level_param_cb(name, ops, arg, perm, 4)
197
198 #define fs_param_cb(name, ops, arg, perm) \
199 __level_param_cb(name, ops, arg, perm, 5)
200
201 #define device_param_cb(name, ops, arg, perm) \
202 __level_param_cb(name, ops, arg, perm, 6)
203
204 #define late_param_cb(name, ops, arg, perm) \
205 __level_param_cb(name, ops, arg, perm, 7)
206
207 /* On alpha, ia64 and ppc64 relocations to global data cannot go into
208 read-only sections (which is part of respective UNIX ABI on these
209 platforms). So 'const' makes no sense and even causes compile failures
210 with some compilers. */
211 #if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64)
212 #define __moduleparam_const
213 #else
214 #define __moduleparam_const const
215 #endif
216
217 /* This is the fundamental function for registering boot/module
218 parameters. */
219 #define __module_param_call(prefix, name, ops, arg, perm, level, flags) \
220 /* Default value instead of permissions? */ \
221 static const char __param_str_##name[] = prefix #name; \
222 static struct kernel_param __moduleparam_const __param_##name \
223 __used \
224 __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
225 = { __param_str_##name, THIS_MODULE, ops, \
226 VERIFY_OCTAL_PERMISSIONS(perm), level, flags, { arg } }
227
228 /* Obsolete - use module_param_cb() */
229 #define module_param_call(name, _set, _get, arg, perm) \
230 static const struct kernel_param_ops __param_ops_##name = \
231 { .flags = 0, .set = _set, .get = _get }; \
232 __module_param_call(MODULE_PARAM_PREFIX, \
233 name, &__param_ops_##name, arg, perm, -1, 0)
234
235 #ifdef CONFIG_SYSFS
236 extern void kernel_param_lock(struct module *mod);
237 extern void kernel_param_unlock(struct module *mod);
238 #else
kernel_param_lock(struct module * mod)239 static inline void kernel_param_lock(struct module *mod)
240 {
241 }
kernel_param_unlock(struct module * mod)242 static inline void kernel_param_unlock(struct module *mod)
243 {
244 }
245 #endif
246
247 #ifndef MODULE
248 /**
249 * core_param - define a historical core kernel parameter.
250 * @name: the name of the cmdline and sysfs parameter (often the same as var)
251 * @var: the variable
252 * @type: the type of the parameter
253 * @perm: visibility in sysfs
254 *
255 * core_param is just like module_param(), but cannot be modular and
256 * doesn't add a prefix (such as "printk."). This is for compatibility
257 * with __setup(), and it makes sense as truly core parameters aren't
258 * tied to the particular file they're in.
259 */
260 #define core_param(name, var, type, perm) \
261 param_check_##type(name, &(var)); \
262 __module_param_call("", name, ¶m_ops_##type, &var, perm, -1, 0)
263
264 /**
265 * core_param_unsafe - same as core_param but taints kernel
266 */
267 #define core_param_unsafe(name, var, type, perm) \
268 param_check_##type(name, &(var)); \
269 __module_param_call("", name, ¶m_ops_##type, &var, perm, \
270 -1, KERNEL_PARAM_FL_UNSAFE)
271
272 #endif /* !MODULE */
273
274 /**
275 * module_param_string - a char array parameter
276 * @name: the name of the parameter
277 * @string: the string variable
278 * @len: the maximum length of the string, incl. terminator
279 * @perm: visibility in sysfs.
280 *
281 * This actually copies the string when it's set (unlike type charp).
282 * @len is usually just sizeof(string).
283 */
284 #define module_param_string(name, string, len, perm) \
285 static const struct kparam_string __param_string_##name \
286 = { len, string }; \
287 __module_param_call(MODULE_PARAM_PREFIX, name, \
288 ¶m_ops_string, \
289 .str = &__param_string_##name, perm, -1, 0);\
290 __MODULE_PARM_TYPE(name, "string")
291
292 /**
293 * parameq - checks if two parameter names match
294 * @name1: parameter name 1
295 * @name2: parameter name 2
296 *
297 * Returns true if the two parameter names are equal.
298 * Dashes (-) are considered equal to underscores (_).
299 */
300 extern bool parameq(const char *name1, const char *name2);
301
302 /**
303 * parameqn - checks if two parameter names match
304 * @name1: parameter name 1
305 * @name2: parameter name 2
306 * @n: the length to compare
307 *
308 * Similar to parameq(), except it compares @n characters.
309 */
310 extern bool parameqn(const char *name1, const char *name2, size_t n);
311
312 /* Called on module insert or kernel boot */
313 extern char *parse_args(const char *name,
314 char *args,
315 const struct kernel_param *params,
316 unsigned num,
317 s16 level_min,
318 s16 level_max,
319 void *arg,
320 int (*unknown)(char *param, char *val,
321 const char *doing, void *arg));
322
323 /* Called by module remove. */
324 #ifdef CONFIG_SYSFS
325 extern void destroy_params(const struct kernel_param *params, unsigned num);
326 #else
destroy_params(const struct kernel_param * params,unsigned num)327 static inline void destroy_params(const struct kernel_param *params,
328 unsigned num)
329 {
330 }
331 #endif /* !CONFIG_SYSFS */
332
333 /* All the helper functions */
334 /* The macros to do compile-time type checking stolen from Jakub
335 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */
336 #define __param_check(name, p, type) \
337 static inline type __always_unused *__check_##name(void) { return(p); }
338
339 extern const struct kernel_param_ops param_ops_byte;
340 extern int param_set_byte(const char *val, const struct kernel_param *kp);
341 extern int param_get_byte(char *buffer, const struct kernel_param *kp);
342 #define param_check_byte(name, p) __param_check(name, p, unsigned char)
343
344 extern const struct kernel_param_ops param_ops_short;
345 extern int param_set_short(const char *val, const struct kernel_param *kp);
346 extern int param_get_short(char *buffer, const struct kernel_param *kp);
347 #define param_check_short(name, p) __param_check(name, p, short)
348
349 extern const struct kernel_param_ops param_ops_ushort;
350 extern int param_set_ushort(const char *val, const struct kernel_param *kp);
351 extern int param_get_ushort(char *buffer, const struct kernel_param *kp);
352 #define param_check_ushort(name, p) __param_check(name, p, unsigned short)
353
354 extern const struct kernel_param_ops param_ops_int;
355 extern int param_set_int(const char *val, const struct kernel_param *kp);
356 extern int param_get_int(char *buffer, const struct kernel_param *kp);
357 #define param_check_int(name, p) __param_check(name, p, int)
358
359 extern const struct kernel_param_ops param_ops_uint;
360 extern int param_set_uint(const char *val, const struct kernel_param *kp);
361 extern int param_get_uint(char *buffer, const struct kernel_param *kp);
362 #define param_check_uint(name, p) __param_check(name, p, unsigned int)
363
364 extern const struct kernel_param_ops param_ops_long;
365 extern int param_set_long(const char *val, const struct kernel_param *kp);
366 extern int param_get_long(char *buffer, const struct kernel_param *kp);
367 #define param_check_long(name, p) __param_check(name, p, long)
368
369 extern const struct kernel_param_ops param_ops_ulong;
370 extern int param_set_ulong(const char *val, const struct kernel_param *kp);
371 extern int param_get_ulong(char *buffer, const struct kernel_param *kp);
372 #define param_check_ulong(name, p) __param_check(name, p, unsigned long)
373
374 extern const struct kernel_param_ops param_ops_ullong;
375 extern int param_set_ullong(const char *val, const struct kernel_param *kp);
376 extern int param_get_ullong(char *buffer, const struct kernel_param *kp);
377 #define param_check_ullong(name, p) __param_check(name, p, unsigned long long)
378
379 extern const struct kernel_param_ops param_ops_charp;
380 extern int param_set_charp(const char *val, const struct kernel_param *kp);
381 extern int param_get_charp(char *buffer, const struct kernel_param *kp);
382 extern void param_free_charp(void *arg);
383 #define param_check_charp(name, p) __param_check(name, p, char *)
384
385 /* We used to allow int as well as bool. We're taking that away! */
386 extern const struct kernel_param_ops param_ops_bool;
387 extern int param_set_bool(const char *val, const struct kernel_param *kp);
388 extern int param_get_bool(char *buffer, const struct kernel_param *kp);
389 #define param_check_bool(name, p) __param_check(name, p, bool)
390
391 extern const struct kernel_param_ops param_ops_bool_enable_only;
392 extern int param_set_bool_enable_only(const char *val,
393 const struct kernel_param *kp);
394 /* getter is the same as for the regular bool */
395 #define param_check_bool_enable_only param_check_bool
396
397 extern const struct kernel_param_ops param_ops_invbool;
398 extern int param_set_invbool(const char *val, const struct kernel_param *kp);
399 extern int param_get_invbool(char *buffer, const struct kernel_param *kp);
400 #define param_check_invbool(name, p) __param_check(name, p, bool)
401
402 /* An int, which can only be set like a bool (though it shows as an int). */
403 extern const struct kernel_param_ops param_ops_bint;
404 extern int param_set_bint(const char *val, const struct kernel_param *kp);
405 #define param_get_bint param_get_int
406 #define param_check_bint param_check_int
407
408 /**
409 * module_param_array - a parameter which is an array of some type
410 * @name: the name of the array variable
411 * @type: the type, as per module_param()
412 * @nump: optional pointer filled in with the number written
413 * @perm: visibility in sysfs
414 *
415 * Input and output are as comma-separated values. Commas inside values
416 * don't work properly (eg. an array of charp).
417 *
418 * ARRAY_SIZE(@name) is used to determine the number of elements in the
419 * array, so the definition must be visible.
420 */
421 #define module_param_array(name, type, nump, perm) \
422 module_param_array_named(name, name, type, nump, perm)
423
424 /**
425 * module_param_array_named - renamed parameter which is an array of some type
426 * @name: a valid C identifier which is the parameter name
427 * @array: the name of the array variable
428 * @type: the type, as per module_param()
429 * @nump: optional pointer filled in with the number written
430 * @perm: visibility in sysfs
431 *
432 * This exposes a different name than the actual variable name. See
433 * module_param_named() for why this might be necessary.
434 */
435 #define module_param_array_named(name, array, type, nump, perm) \
436 param_check_##type(name, &(array)[0]); \
437 static const struct kparam_array __param_arr_##name \
438 = { .max = ARRAY_SIZE(array), .num = nump, \
439 .ops = ¶m_ops_##type, \
440 .elemsize = sizeof(array[0]), .elem = array }; \
441 __module_param_call(MODULE_PARAM_PREFIX, name, \
442 ¶m_array_ops, \
443 .arr = &__param_arr_##name, \
444 perm, -1, 0); \
445 __MODULE_PARM_TYPE(name, "array of " #type)
446
447 enum hwparam_type {
448 hwparam_ioport, /* Module parameter configures an I/O port */
449 hwparam_iomem, /* Module parameter configures an I/O mem address */
450 hwparam_ioport_or_iomem, /* Module parameter could be either, depending on other option */
451 hwparam_irq, /* Module parameter configures an IRQ */
452 hwparam_dma, /* Module parameter configures a DMA channel */
453 hwparam_dma_addr, /* Module parameter configures a DMA buffer address */
454 hwparam_other, /* Module parameter configures some other value */
455 };
456
457 /**
458 * module_param_hw_named - A parameter representing a hw parameters
459 * @name: a valid C identifier which is the parameter name.
460 * @value: the actual lvalue to alter.
461 * @type: the type of the parameter
462 * @hwtype: what the value represents (enum hwparam_type)
463 * @perm: visibility in sysfs.
464 *
465 * Usually it's a good idea to have variable names and user-exposed names the
466 * same, but that's harder if the variable must be non-static or is inside a
467 * structure. This allows exposure under a different name.
468 */
469 #define module_param_hw_named(name, value, type, hwtype, perm) \
470 param_check_##type(name, &(value)); \
471 __module_param_call(MODULE_PARAM_PREFIX, name, \
472 ¶m_ops_##type, &value, \
473 perm, -1, \
474 KERNEL_PARAM_FL_HWPARAM | (hwparam_##hwtype & 0)); \
475 __MODULE_PARM_TYPE(name, #type)
476
477 #define module_param_hw(name, type, hwtype, perm) \
478 module_param_hw_named(name, name, type, hwtype, perm)
479
480 /**
481 * module_param_hw_array - A parameter representing an array of hw parameters
482 * @name: the name of the array variable
483 * @type: the type, as per module_param()
484 * @hwtype: what the value represents (enum hwparam_type)
485 * @nump: optional pointer filled in with the number written
486 * @perm: visibility in sysfs
487 *
488 * Input and output are as comma-separated values. Commas inside values
489 * don't work properly (eg. an array of charp).
490 *
491 * ARRAY_SIZE(@name) is used to determine the number of elements in the
492 * array, so the definition must be visible.
493 */
494 #define module_param_hw_array(name, type, hwtype, nump, perm) \
495 param_check_##type(name, &(name)[0]); \
496 static const struct kparam_array __param_arr_##name \
497 = { .max = ARRAY_SIZE(name), .num = nump, \
498 .ops = ¶m_ops_##type, \
499 .elemsize = sizeof(name[0]), .elem = name }; \
500 __module_param_call(MODULE_PARAM_PREFIX, name, \
501 ¶m_array_ops, \
502 .arr = &__param_arr_##name, \
503 perm, -1, \
504 KERNEL_PARAM_FL_HWPARAM | (hwparam_##hwtype & 0)); \
505 __MODULE_PARM_TYPE(name, "array of " #type)
506
507
508 extern const struct kernel_param_ops param_array_ops;
509
510 extern const struct kernel_param_ops param_ops_string;
511 extern int param_set_copystring(const char *val, const struct kernel_param *);
512 extern int param_get_string(char *buffer, const struct kernel_param *kp);
513
514 /* for exporting parameters in /sys/module/.../parameters */
515
516 struct module;
517
518 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES)
519 extern int module_param_sysfs_setup(struct module *mod,
520 const struct kernel_param *kparam,
521 unsigned int num_params);
522
523 extern void module_param_sysfs_remove(struct module *mod);
524 #else
module_param_sysfs_setup(struct module * mod,const struct kernel_param * kparam,unsigned int num_params)525 static inline int module_param_sysfs_setup(struct module *mod,
526 const struct kernel_param *kparam,
527 unsigned int num_params)
528 {
529 return 0;
530 }
531
module_param_sysfs_remove(struct module * mod)532 static inline void module_param_sysfs_remove(struct module *mod)
533 { }
534 #endif
535
536 #endif /* _LINUX_MODULE_PARAMS_H */
537
