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Diffstat (limited to 'include/linux/moduleparam.h')
| -rw-r--r-- | include/linux/moduleparam.h | 411 |
1 files changed, 411 insertions, 0 deletions
diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h new file mode 100644 index 00000000..ddaae98c --- /dev/null +++ b/include/linux/moduleparam.h @@ -0,0 +1,411 @@ +#ifndef _LINUX_MODULE_PARAMS_H +#define _LINUX_MODULE_PARAMS_H +/* (C) Copyright 2001, 2002 Rusty Russell IBM Corporation */ +#include <linux/init.h> +#include <linux/stringify.h> +#include <linux/kernel.h> + +/* You can override this manually, but generally this should match the + module name. */ +#ifdef MODULE +#define MODULE_PARAM_PREFIX /* empty */ +#else +#define MODULE_PARAM_PREFIX KBUILD_MODNAME "." +#endif + +/* Chosen so that structs with an unsigned long line up. */ +#define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long)) + +#define ___module_cat(a,b) __mod_ ## a ## b +#define __module_cat(a,b) ___module_cat(a,b) +#ifdef MODULE +#define __MODULE_INFO(tag, name, info) \ +static const char __module_cat(name,__LINE__)[] \ + __used __attribute__((section(".modinfo"), unused, aligned(1))) \ + = __stringify(tag) "=" info +#else /* !MODULE */ +/* This struct is here for syntactic coherency, it is not used */ +#define __MODULE_INFO(tag, name, info) \ + struct __module_cat(name,__LINE__) {} +#endif +#define __MODULE_PARM_TYPE(name, _type) \ + __MODULE_INFO(parmtype, name##type, #name ":" _type) + +struct kernel_param; + +struct kernel_param_ops { + /* Returns 0, or -errno. arg is in kp->arg. */ + int (*set)(const char *val, const struct kernel_param *kp); + /* Returns length written or -errno. Buffer is 4k (ie. be short!) */ + int (*get)(char *buffer, const struct kernel_param *kp); + /* Optional function to free kp->arg when module unloaded. */ + void (*free)(void *arg); +}; + +/* Flag bits for kernel_param.flags */ +#define KPARAM_ISBOOL 2 + +struct kernel_param { + const char *name; + const struct kernel_param_ops *ops; + u16 perm; + u16 flags; + union { + void *arg; + const struct kparam_string *str; + const struct kparam_array *arr; + }; +}; + +/* Special one for strings we want to copy into */ +struct kparam_string { + unsigned int maxlen; + char *string; +}; + +/* Special one for arrays */ +struct kparam_array +{ + unsigned int max; + unsigned int elemsize; + unsigned int *num; + const struct kernel_param_ops *ops; + void *elem; +}; + +/** + * module_param - typesafe helper for a module/cmdline parameter + * @value: the variable to alter, and exposed parameter name. + * @type: the type of the parameter + * @perm: visibility in sysfs. + * + * @value becomes the module parameter, or (prefixed by KBUILD_MODNAME and a + * ".") the kernel commandline parameter. Note that - is changed to _, so + * the user can use "foo-bar=1" even for variable "foo_bar". + * + * @perm is 0 if the the variable is not to appear in sysfs, or 0444 + * for world-readable, 0644 for root-writable, etc. Note that if it + * is writable, you may need to use kparam_block_sysfs_write() around + * accesses (esp. charp, which can be kfreed when it changes). + * + * The @type is simply pasted to refer to a param_ops_##type and a + * param_check_##type: for convenience many standard types are provided but + * you can create your own by defining those variables. + * + * Standard types are: + * byte, short, ushort, int, uint, long, ulong + * charp: a character pointer + * bool: a bool, values 0/1, y/n, Y/N. + * invbool: the above, only sense-reversed (N = true). + */ +#define module_param(name, type, perm) \ + module_param_named(name, name, type, perm) + +/** + * module_param_named - typesafe helper for a renamed module/cmdline parameter + * @name: a valid C identifier which is the parameter name. + * @value: the actual lvalue to alter. + * @type: the type of the parameter + * @perm: visibility in sysfs. + * + * Usually it's a good idea to have variable names and user-exposed names the + * same, but that's harder if the variable must be non-static or is inside a + * structure. This allows exposure under a different name. + */ +#define module_param_named(name, value, type, perm) \ + param_check_##type(name, &(value)); \ + module_param_cb(name, ¶m_ops_##type, &value, perm); \ + __MODULE_PARM_TYPE(name, #type) + +/** + * module_param_cb - general callback for a module/cmdline parameter + * @name: a valid C identifier which is the parameter name. + * @ops: the set & get operations for this parameter. + * @perm: visibility in sysfs. + * + * The ops can have NULL set or get functions. + */ +#define module_param_cb(name, ops, arg, perm) \ + __module_param_call(MODULE_PARAM_PREFIX, \ + name, ops, arg, __same_type((arg), bool *), perm) + +/* On alpha, ia64 and ppc64 relocations to global data cannot go into + read-only sections (which is part of respective UNIX ABI on these + platforms). So 'const' makes no sense and even causes compile failures + with some compilers. */ +#if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64) +#define __moduleparam_const +#else +#define __moduleparam_const const +#endif + +/* This is the fundamental function for registering boot/module + parameters. */ +#define __module_param_call(prefix, name, ops, arg, isbool, perm) \ + /* Default value instead of permissions? */ \ + static int __param_perm_check_##name __attribute__((unused)) = \ + BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2)) \ + + BUILD_BUG_ON_ZERO(sizeof(""prefix) > MAX_PARAM_PREFIX_LEN); \ + static const char __param_str_##name[] = prefix #name; \ + static struct kernel_param __moduleparam_const __param_##name \ + __used \ + __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \ + = { __param_str_##name, ops, perm, isbool ? KPARAM_ISBOOL : 0, \ + { arg } } + +/* Obsolete - use module_param_cb() */ +#define module_param_call(name, set, get, arg, perm) \ + static struct kernel_param_ops __param_ops_##name = \ + { (void *)set, (void *)get }; \ + __module_param_call(MODULE_PARAM_PREFIX, \ + name, &__param_ops_##name, arg, \ + __same_type(arg, bool *), \ + (perm) + sizeof(__check_old_set_param(set))*0) + +/* We don't get oldget: it's often a new-style param_get_uint, etc. */ +static inline int +__check_old_set_param(int (*oldset)(const char *, struct kernel_param *)) +{ + return 0; +} + +/** + * kparam_block_sysfs_write - make sure a parameter isn't written via sysfs. + * @name: the name of the parameter + * + * There's no point blocking write on a paramter that isn't writable via sysfs! + */ +#define kparam_block_sysfs_write(name) \ + do { \ + BUG_ON(!(__param_##name.perm & 0222)); \ + __kernel_param_lock(); \ + } while (0) + +/** + * kparam_unblock_sysfs_write - allows sysfs to write to a parameter again. + * @name: the name of the parameter + */ +#define kparam_unblock_sysfs_write(name) \ + do { \ + BUG_ON(!(__param_##name.perm & 0222)); \ + __kernel_param_unlock(); \ + } while (0) + +/** + * kparam_block_sysfs_read - make sure a parameter isn't read via sysfs. + * @name: the name of the parameter + * + * This also blocks sysfs writes. + */ +#define kparam_block_sysfs_read(name) \ + do { \ + BUG_ON(!(__param_##name.perm & 0444)); \ + __kernel_param_lock(); \ + } while (0) + +/** + * kparam_unblock_sysfs_read - allows sysfs to read a parameter again. + * @name: the name of the parameter + */ +#define kparam_unblock_sysfs_read(name) \ + do { \ + BUG_ON(!(__param_##name.perm & 0444)); \ + __kernel_param_unlock(); \ + } while (0) + +#ifdef CONFIG_SYSFS +extern void __kernel_param_lock(void); +extern void __kernel_param_unlock(void); +#else +static inline void __kernel_param_lock(void) +{ +} +static inline void __kernel_param_unlock(void) +{ +} +#endif + +#ifndef MODULE +/** + * core_param - define a historical core kernel parameter. + * @name: the name of the cmdline and sysfs parameter (often the same as var) + * @var: the variable + * @type: the type of the parameter + * @perm: visibility in sysfs + * + * core_param is just like module_param(), but cannot be modular and + * doesn't add a prefix (such as "printk."). This is for compatibility + * with __setup(), and it makes sense as truly core parameters aren't + * tied to the particular file they're in. + */ +#define core_param(name, var, type, perm) \ + param_check_##type(name, &(var)); \ + __module_param_call("", name, ¶m_ops_##type, \ + &var, __same_type(var, bool), perm) +#endif /* !MODULE */ + +/** + * module_param_string - a char array parameter + * @name: the name of the parameter + * @string: the string variable + * @len: the maximum length of the string, incl. terminator + * @perm: visibility in sysfs. + * + * This actually copies the string when it's set (unlike type charp). + * @len is usually just sizeof(string). + */ +#define module_param_string(name, string, len, perm) \ + static const struct kparam_string __param_string_##name \ + = { len, string }; \ + __module_param_call(MODULE_PARAM_PREFIX, name, \ + ¶m_ops_string, \ + .str = &__param_string_##name, 0, perm); \ + __MODULE_PARM_TYPE(name, "string") + +/* Called on module insert or kernel boot */ +extern int parse_args(const char *name, + char *args, + const struct kernel_param *params, + unsigned num, + int (*unknown)(char *param, char *val)); + +/* Called by module remove. */ +#ifdef CONFIG_SYSFS +extern void destroy_params(const struct kernel_param *params, unsigned num); +#else +static inline void destroy_params(const struct kernel_param *params, + unsigned num) +{ +} +#endif /* !CONFIG_SYSFS */ + +/* All the helper functions */ +/* The macros to do compile-time type checking stolen from Jakub + Jelinek, who IIRC came up with this idea for the 2.4 module init code. */ +#define __param_check(name, p, type) \ + static inline type *__check_##name(void) { return(p); } + +extern struct kernel_param_ops param_ops_byte; +extern int param_set_byte(const char *val, const struct kernel_param *kp); +extern int param_get_byte(char *buffer, const struct kernel_param *kp); +#define param_check_byte(name, p) __param_check(name, p, unsigned char) + +extern struct kernel_param_ops param_ops_short; +extern int param_set_short(const char *val, const struct kernel_param *kp); +extern int param_get_short(char *buffer, const struct kernel_param *kp); +#define param_check_short(name, p) __param_check(name, p, short) + +extern struct kernel_param_ops param_ops_ushort; +extern int param_set_ushort(const char *val, const struct kernel_param *kp); +extern int param_get_ushort(char *buffer, const struct kernel_param *kp); +#define param_check_ushort(name, p) __param_check(name, p, unsigned short) + +extern struct kernel_param_ops param_ops_int; +extern int param_set_int(const char *val, const struct kernel_param *kp); +extern int param_get_int(char *buffer, const struct kernel_param *kp); +#define param_check_int(name, p) __param_check(name, p, int) + +extern struct kernel_param_ops param_ops_uint; +extern int param_set_uint(const char *val, const struct kernel_param *kp); +extern int param_get_uint(char *buffer, const struct kernel_param *kp); +#define param_check_uint(name, p) __param_check(name, p, unsigned int) + +extern struct kernel_param_ops param_ops_long; +extern int param_set_long(const char *val, const struct kernel_param *kp); +extern int param_get_long(char *buffer, const struct kernel_param *kp); +#define param_check_long(name, p) __param_check(name, p, long) + +extern struct kernel_param_ops param_ops_ulong; +extern int param_set_ulong(const char *val, const struct kernel_param *kp); +extern int param_get_ulong(char *buffer, const struct kernel_param *kp); +#define param_check_ulong(name, p) __param_check(name, p, unsigned long) + +extern struct kernel_param_ops param_ops_charp; +extern int param_set_charp(const char *val, const struct kernel_param *kp); +extern int param_get_charp(char *buffer, const struct kernel_param *kp); +#define param_check_charp(name, p) __param_check(name, p, char *) + +/* For historical reasons "bool" parameters can be (unsigned) "int". */ +extern struct kernel_param_ops param_ops_bool; +extern int param_set_bool(const char *val, const struct kernel_param *kp); +extern int param_get_bool(char *buffer, const struct kernel_param *kp); +#define param_check_bool(name, p) \ + static inline void __check_##name(void) \ + { \ + BUILD_BUG_ON(!__same_type((p), bool *) && \ + !__same_type((p), unsigned int *) && \ + !__same_type((p), int *)); \ + } + +extern struct kernel_param_ops param_ops_invbool; +extern int param_set_invbool(const char *val, const struct kernel_param *kp); +extern int param_get_invbool(char *buffer, const struct kernel_param *kp); +#define param_check_invbool(name, p) __param_check(name, p, bool) + +/** + * module_param_array - a parameter which is an array of some type + * @name: the name of the array variable + * @type: the type, as per module_param() + * @nump: optional pointer filled in with the number written + * @perm: visibility in sysfs + * + * Input and output are as comma-separated values. Commas inside values + * don't work properly (eg. an array of charp). + * + * ARRAY_SIZE(@name) is used to determine the number of elements in the + * array, so the definition must be visible. + */ +#define module_param_array(name, type, nump, perm) \ + module_param_array_named(name, name, type, nump, perm) + +/** + * module_param_array_named - renamed parameter which is an array of some type + * @name: a valid C identifier which is the parameter name + * @array: the name of the array variable + * @type: the type, as per module_param() + * @nump: optional pointer filled in with the number written + * @perm: visibility in sysfs + * + * This exposes a different name than the actual variable name. See + * module_param_named() for why this might be necessary. + */ +#define module_param_array_named(name, array, type, nump, perm) \ + static const struct kparam_array __param_arr_##name \ + = { .max = ARRAY_SIZE(array), .num = nump, \ + .ops = ¶m_ops_##type, \ + .elemsize = sizeof(array[0]), .elem = array }; \ + __module_param_call(MODULE_PARAM_PREFIX, name, \ + ¶m_array_ops, \ + .arr = &__param_arr_##name, \ + __same_type(array[0], bool), perm); \ + __MODULE_PARM_TYPE(name, "array of " #type) + +extern struct kernel_param_ops param_array_ops; + +extern struct kernel_param_ops param_ops_string; +extern int param_set_copystring(const char *val, const struct kernel_param *); +extern int param_get_string(char *buffer, const struct kernel_param *kp); + +/* for exporting parameters in /sys/parameters */ + +struct module; + +#if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES) +extern int module_param_sysfs_setup(struct module *mod, + const struct kernel_param *kparam, + unsigned int num_params); + +extern void module_param_sysfs_remove(struct module *mod); +#else +static inline int module_param_sysfs_setup(struct module *mod, + const struct kernel_param *kparam, + unsigned int num_params) +{ + return 0; +} + +static inline void module_param_sysfs_remove(struct module *mod) +{ } +#endif + +#endif /* _LINUX_MODULE_PARAMS_H */ |