include/linux/moduleparam.h

   1 #ifndef _LINUX_MODULE_PARAMS_H
   2 #define _LINUX_MODULE_PARAMS_H
   3 /* (C) Copyright 2001, 2002 Rusty Russell IBM Corporation */
   4 #include <linux/init.h>
   5 #include <linux/stringify.h>
   6 #include <linux/kernel.h>
   7
   8 /* You can override this manually, but generally this should match the
   9    module name. */
  10 #ifdef MODULE
  11 #define MODULE_PARAM_PREFIX /* empty */
  12 #else
  13 #define MODULE_PARAM_PREFIX KBUILD_MODNAME "."
  14 #endif
  15
  16 /* Chosen so that structs with an unsigned long line up. */
  17 #define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long))
  18
  19 #ifdef MODULE
  20 #define ___module_cat(a,b) __mod_ ## a ## b
  21 #define __module_cat(a,b) ___module_cat(a,b)
  22 #define __MODULE_INFO(tag, name, info)                                    \
  23 static const char __module_cat(name,__LINE__)[]                           \
  24   __used                                                                  \
  25   __attribute__((section(".modinfo"),unused)) = __stringify(tag) "=" info
  26 #else  /* !MODULE */
  27 #define __MODULE_INFO(tag, name, info)
  28 #endif
  29 #define __MODULE_PARM_TYPE(name, _type)                                   \
  30   __MODULE_INFO(parmtype, name##type, #name ":" _type)
  31
  32 struct kernel_param;
  33
  34 /* Returns 0, or -errno.  arg is in kp->arg. */
  35 typedef int (*param_set_fn)(const char *val, struct kernel_param *kp);
  36 /* Returns length written or -errno.  Buffer is 4k (ie. be short!) */
  37 typedef int (*param_get_fn)(char *buffer, struct kernel_param *kp);
  38
  39 struct kernel_param {
  40         const char *name;
  41         unsigned int perm;
  42         param_set_fn set;
  43         param_get_fn get;
  44         union {
  45                 void *arg;
  46                 const struct kparam_string *str;
  47                 const struct kparam_array *arr;
  48         };
  49 };
  50
  51 /* Special one for strings we want to copy into */
  52 struct kparam_string {
  53         unsigned int maxlen;
  54         char *string;
  55 };
  56
  57 /* Special one for arrays */
  58 struct kparam_array
  59 {
  60         unsigned int max;
  61         unsigned int *num;
  62         param_set_fn set;
  63         param_get_fn get;
  64         unsigned int elemsize;
  65         void *elem;
  66 };
  67
  68 /* On alpha, ia64 and ppc64 relocations to global data cannot go into
  69    read-only sections (which is part of respective UNIX ABI on these
  70    platforms). So 'const' makes no sense and even causes compile failures
  71    with some compilers. */
  72 #if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64)
  73 #define __moduleparam_const
  74 #else
  75 #define __moduleparam_const const
  76 #endif
  77
  78 /* This is the fundamental function for registering boot/module
  79    parameters.  perm sets the visibility in sysfs: 000 means it's
  80    not there, read bits mean it's readable, write bits mean it's
  81    writable. */
  82 #define __module_param_call(prefix, name, set, get, arg, perm)          \
  83         /* Default value instead of permissions? */                     \
  84         static int __param_perm_check_##name __attribute__((unused)) =  \
  85         BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2))  \
  86         + BUILD_BUG_ON_ZERO(sizeof(""prefix) > MAX_PARAM_PREFIX_LEN);   \
  87         static const char __param_str_##name[] = prefix #name;          \
  88         static struct kernel_param __moduleparam_const __param_##name   \
  89         __used                                                          \
  90     __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
  91         = { __param_str_##name, perm, set, get, { arg } }
  92
  93 #define module_param_call(name, set, get, arg, perm)                          \
  94         __module_param_call(MODULE_PARAM_PREFIX, name, set, get, arg, perm)
  95
  96 /* Helper functions: type is byte, short, ushort, int, uint, long,
  97    ulong, charp, bool or invbool, or XXX if you define param_get_XXX,
  98    param_set_XXX and param_check_XXX. */
  99 #define module_param_named(name, value, type, perm)                        \
 100         param_check_##type(name, &(value));                                \
 101         module_param_call(name, param_set_##type, param_get_##type, &value, perm); \
 102         __MODULE_PARM_TYPE(name, #type)
 103
 104 #define module_param(name, type, perm)                          \
 105         module_param_named(name, name, type, perm)
 106
 107 #ifndef MODULE
 108 /**
 109  * core_param - define a historical core kernel parameter.
 110  * @name: the name of the cmdline and sysfs parameter (often the same as var)
 111  * @var: the variable
 112  * @type: the type (for param_set_##type and param_get_##type)
 113  * @perm: visibility in sysfs
 114  *
 115  * core_param is just like module_param(), but cannot be modular and
 116  * doesn't add a prefix (such as "printk.").  This is for compatibility
 117  * with __setup(), and it makes sense as truly core parameters aren't
 118  * tied to the particular file they're in.
 119  */
 120 #define core_param(name, var, type, perm)                               \
 121         param_check_##type(name, &(var));                               \
 122         __module_param_call("", name, param_set_##type, param_get_##type, \
 123                             &var, perm)
 124 #endif /* !MODULE */
 125
 126 /* Actually copy string: maxlen param is usually sizeof(string). */
 127 #define module_param_string(name, string, len, perm)                    \
 128         static const struct kparam_string __param_string_##name         \
 129                 = { len, string };                                      \
 130         module_param_call(name, param_set_copystring, param_get_string, \
 131                           .str = &__param_string_##name, perm);         \
 132         __MODULE_PARM_TYPE(name, "string")
 133
 134 /* Called on module insert or kernel boot */
 135 extern int parse_args(const char *name,
 136                       char *args,
 137                       struct kernel_param *params,
 138                       unsigned num,
 139                       int (*unknown)(char *param, char *val));
 140
 141 /* All the helper functions */
 142 /* The macros to do compile-time type checking stolen from Jakub
 143    Jelinek, who IIRC came up with this idea for the 2.4 module init code. */
 144 #define __param_check(name, p, type) \
 145         static inline type *__check_##name(void) { return(p); }
 146
 147 extern int param_set_byte(const char *val, struct kernel_param *kp);
 148 extern int param_get_byte(char *buffer, struct kernel_param *kp);
 149 #define param_check_byte(name, p) __param_check(name, p, unsigned char)
 150
 151 extern int param_set_short(const char *val, struct kernel_param *kp);
 152 extern int param_get_short(char *buffer, struct kernel_param *kp);
 153 #define param_check_short(name, p) __param_check(name, p, short)
 154
 155 extern int param_set_ushort(const char *val, struct kernel_param *kp);
 156 extern int param_get_ushort(char *buffer, struct kernel_param *kp);
 157 #define param_check_ushort(name, p) __param_check(name, p, unsigned short)
 158
 159 extern int param_set_int(const char *val, struct kernel_param *kp);
 160 extern int param_get_int(char *buffer, struct kernel_param *kp);
 161 #define param_check_int(name, p) __param_check(name, p, int)
 162
 163 extern int param_set_uint(const char *val, struct kernel_param *kp);
 164 extern int param_get_uint(char *buffer, struct kernel_param *kp);
 165 #define param_check_uint(name, p) __param_check(name, p, unsigned int)
 166
 167 extern int param_set_long(const char *val, struct kernel_param *kp);
 168 extern int param_get_long(char *buffer, struct kernel_param *kp);
 169 #define param_check_long(name, p) __param_check(name, p, long)
 170
 171 extern int param_set_ulong(const char *val, struct kernel_param *kp);
 172 extern int param_get_ulong(char *buffer, struct kernel_param *kp);
 173 #define param_check_ulong(name, p) __param_check(name, p, unsigned long)
 174
 175 extern int param_set_charp(const char *val, struct kernel_param *kp);
 176 extern int param_get_charp(char *buffer, struct kernel_param *kp);
 177 #define param_check_charp(name, p) __param_check(name, p, char *)
 178
 179 extern int param_set_bool(const char *val, struct kernel_param *kp);
 180 extern int param_get_bool(char *buffer, struct kernel_param *kp);
 181 #define param_check_bool(name, p) __param_check(name, p, int)
 182
 183 extern int param_set_invbool(const char *val, struct kernel_param *kp);
 184 extern int param_get_invbool(char *buffer, struct kernel_param *kp);
 185 #define param_check_invbool(name, p) __param_check(name, p, int)
 186
 187 /* Comma-separated array: *nump is set to number they actually specified. */
 188 #define module_param_array_named(name, array, type, nump, perm)         \
 189         static const struct kparam_array __param_arr_##name             \
 190         = { ARRAY_SIZE(array), nump, param_set_##type, param_get_##type,\
 191             sizeof(array[0]), array };                                  \
 192         module_param_call(name, param_array_set, param_array_get,       \
 193                           .arr = &__param_arr_##name, perm);            \
 194         __MODULE_PARM_TYPE(name, "array of " #type)
 195
 196 #define module_param_array(name, type, nump, perm)              \
 197         module_param_array_named(name, name, type, nump, perm)
 198
 199 extern int param_array_set(const char *val, struct kernel_param *kp);
 200 extern int param_array_get(char *buffer, struct kernel_param *kp);
 201
 202 extern int param_set_copystring(const char *val, struct kernel_param *kp);
 203 extern int param_get_string(char *buffer, struct kernel_param *kp);
 204
 205 /* for exporting parameters in /sys/parameters */
 206
 207 struct module;
 208
 209 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES)
 210 extern int module_param_sysfs_setup(struct module *mod,
 211                                     struct kernel_param *kparam,
 212                                     unsigned int num_params);
 213
 214 extern void module_param_sysfs_remove(struct module *mod);
 215 #else
 216 static inline int module_param_sysfs_setup(struct module *mod,
 217                              struct kernel_param *kparam,
 218                              unsigned int num_params)
 219 {
 220         return 0;
 221 }
 222
 223 static inline void module_param_sysfs_remove(struct module *mod)
 224 { }
 225 #endif
 226
 227 #endif /* _LINUX_MODULE_PARAMS_H */