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 /* Flag bits for kernel_param.flags */
  40 #define KPARAM_KMALLOCED        1
  41 #define KPARAM_ISBOOL           2
  42
  43 struct kernel_param {
  44         const char *name;
  45         u16 perm;
  46         u16 flags;
  47         param_set_fn set;
  48         param_get_fn get;
  49         union {
  50                 void *arg;
  51                 const struct kparam_string *str;
  52                 const struct kparam_array *arr;
  53         };
  54 };
  55
  56 /* Special one for strings we want to copy into */
  57 struct kparam_string {
  58         unsigned int maxlen;
  59         char *string;
  60 };
  61
  62 /* Special one for arrays */
  63 struct kparam_array
  64 {
  65         unsigned int max;
  66         unsigned int *num;
  67         param_set_fn set;
  68         param_get_fn get;
  69         unsigned int elemsize;
  70         void *elem;
  71 };
  72
  73 /* On alpha, ia64 and ppc64 relocations to global data cannot go into
  74    read-only sections (which is part of respective UNIX ABI on these
  75    platforms). So 'const' makes no sense and even causes compile failures
  76    with some compilers. */
  77 #if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64)
  78 #define __moduleparam_const
  79 #else
  80 #define __moduleparam_const const
  81 #endif
  82
  83 /* This is the fundamental function for registering boot/module
  84    parameters.  perm sets the visibility in sysfs: 000 means it's
  85    not there, read bits mean it's readable, write bits mean it's
  86    writable. */
  87 #define __module_param_call(prefix, name, set, get, arg, isbool, perm)  \
  88         /* Default value instead of permissions? */                     \
  89         static int __param_perm_check_##name __attribute__((unused)) =  \
  90         BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2))  \
  91         + BUILD_BUG_ON_ZERO(sizeof(""prefix) > MAX_PARAM_PREFIX_LEN);   \
  92         static const char __param_str_##name[] = prefix #name;          \
  93         static struct kernel_param __moduleparam_const __param_##name   \
  94         __used                                                          \
  95     __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
  96         = { __param_str_##name, perm, isbool ? KPARAM_ISBOOL : 0,       \
  97             set, get, { arg } }
  98
  99 #define module_param_call(name, set, get, arg, perm)                          \
 100         __module_param_call(MODULE_PARAM_PREFIX,                              \
 101                             name, set, get, arg,                              \
 102                             __same_type(*(arg), bool), perm)
 103
 104 /* Helper functions: type is byte, short, ushort, int, uint, long,
 105    ulong, charp, bool or invbool, or XXX if you define param_get_XXX,
 106    param_set_XXX and param_check_XXX. */
 107 #define module_param_named(name, value, type, perm)                        \
 108         param_check_##type(name, &(value));                                \
 109         module_param_call(name, param_set_##type, param_get_##type, &value, perm); \
 110         __MODULE_PARM_TYPE(name, #type)
 111
 112 #define module_param(name, type, perm)                          \
 113         module_param_named(name, name, type, perm)
 114
 115 #ifndef MODULE
 116 /**
 117  * core_param - define a historical core kernel parameter.
 118  * @name: the name of the cmdline and sysfs parameter (often the same as var)
 119  * @var: the variable
 120  * @type: the type (for param_set_##type and param_get_##type)
 121  * @perm: visibility in sysfs
 122  *
 123  * core_param is just like module_param(), but cannot be modular and
 124  * doesn't add a prefix (such as "printk.").  This is for compatibility
 125  * with __setup(), and it makes sense as truly core parameters aren't
 126  * tied to the particular file they're in.
 127  */
 128 #define core_param(name, var, type, perm)                               \
 129         param_check_##type(name, &(var));                               \
 130         __module_param_call("", name, param_set_##type, param_get_##type, \
 131                             &var, __same_type(var, bool), perm)
 132 #endif /* !MODULE */
 133
 134 /* Actually copy string: maxlen param is usually sizeof(string). */
 135 #define module_param_string(name, string, len, perm)                    \
 136         static const struct kparam_string __param_string_##name         \
 137                 = { len, string };                                      \
 138         __module_param_call(MODULE_PARAM_PREFIX, name,                  \
 139                             param_set_copystring, param_get_string,     \
 140                             .str = &__param_string_##name, 0, perm);    \
 141         __MODULE_PARM_TYPE(name, "string")
 142
 143 /* Called on module insert or kernel boot */
 144 extern int parse_args(const char *name,
 145                       char *args,
 146                       struct kernel_param *params,
 147                       unsigned num,
 148                       int (*unknown)(char *param, char *val));
 149
 150 /* Called by module remove. */
 151 #ifdef CONFIG_SYSFS
 152 extern void destroy_params(const struct kernel_param *params, unsigned num);
 153 #else
 154 static inline void destroy_params(const struct kernel_param *params,
 155                                   unsigned num)
 156 {
 157 }
 158 #endif /* !CONFIG_SYSFS */
 159
 160 /* All the helper functions */
 161 /* The macros to do compile-time type checking stolen from Jakub
 162    Jelinek, who IIRC came up with this idea for the 2.4 module init code. */
 163 #define __param_check(name, p, type) \
 164         static inline type *__check_##name(void) { return(p); }
 165
 166 extern int param_set_byte(const char *val, struct kernel_param *kp);
 167 extern int param_get_byte(char *buffer, struct kernel_param *kp);
 168 #define param_check_byte(name, p) __param_check(name, p, unsigned char)
 169
 170 extern int param_set_short(const char *val, struct kernel_param *kp);
 171 extern int param_get_short(char *buffer, struct kernel_param *kp);
 172 #define param_check_short(name, p) __param_check(name, p, short)
 173
 174 extern int param_set_ushort(const char *val, struct kernel_param *kp);
 175 extern int param_get_ushort(char *buffer, struct kernel_param *kp);
 176 #define param_check_ushort(name, p) __param_check(name, p, unsigned short)
 177
 178 extern int param_set_int(const char *val, struct kernel_param *kp);
 179 extern int param_get_int(char *buffer, struct kernel_param *kp);
 180 #define param_check_int(name, p) __param_check(name, p, int)
 181
 182 extern int param_set_uint(const char *val, struct kernel_param *kp);
 183 extern int param_get_uint(char *buffer, struct kernel_param *kp);
 184 #define param_check_uint(name, p) __param_check(name, p, unsigned int)
 185
 186 extern int param_set_long(const char *val, struct kernel_param *kp);
 187 extern int param_get_long(char *buffer, struct kernel_param *kp);
 188 #define param_check_long(name, p) __param_check(name, p, long)
 189
 190 extern int param_set_ulong(const char *val, struct kernel_param *kp);
 191 extern int param_get_ulong(char *buffer, struct kernel_param *kp);
 192 #define param_check_ulong(name, p) __param_check(name, p, unsigned long)
 193
 194 extern int param_set_charp(const char *val, struct kernel_param *kp);
 195 extern int param_get_charp(char *buffer, struct kernel_param *kp);
 196 #define param_check_charp(name, p) __param_check(name, p, char *)
 197
 198 /* For historical reasons "bool" parameters can be (unsigned) "int". */
 199 extern int param_set_bool(const char *val, struct kernel_param *kp);
 200 extern int param_get_bool(char *buffer, struct kernel_param *kp);
 201 #define param_check_bool(name, p)                                       \
 202         static inline void __check_##name(void)                         \
 203         {                                                               \
 204                 BUILD_BUG_ON(!__same_type(*(p), bool) &&                \
 205                              !__same_type(*(p), unsigned int) &&        \
 206                              !__same_type(*(p), int));                  \
 207         }
 208
 209 extern int param_set_invbool(const char *val, struct kernel_param *kp);
 210 extern int param_get_invbool(char *buffer, struct kernel_param *kp);
 211 #define param_check_invbool(name, p) __param_check(name, p, bool)
 212
 213 /* Comma-separated array: *nump is set to number they actually specified. */
 214 #define module_param_array_named(name, array, type, nump, perm)         \
 215         static const struct kparam_array __param_arr_##name             \
 216         = { ARRAY_SIZE(array), nump, param_set_##type, param_get_##type,\
 217             sizeof(array[0]), array };                                  \
 218         __module_param_call(MODULE_PARAM_PREFIX, name,                  \
 219                             param_array_set, param_array_get,           \
 220                             .arr = &__param_arr_##name,                 \
 221                             __same_type(array[0], bool), perm);         \
 222         __MODULE_PARM_TYPE(name, "array of " #type)
 223
 224 #define module_param_array(name, type, nump, perm)              \
 225         module_param_array_named(name, name, type, nump, perm)
 226
 227 extern int param_array_set(const char *val, struct kernel_param *kp);
 228 extern int param_array_get(char *buffer, struct kernel_param *kp);
 229
 230 extern int param_set_copystring(const char *val, struct kernel_param *kp);
 231 extern int param_get_string(char *buffer, struct kernel_param *kp);
 232
 233 /* for exporting parameters in /sys/parameters */
 234
 235 struct module;
 236
 237 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES)
 238 extern int module_param_sysfs_setup(struct module *mod,
 239                                     struct kernel_param *kparam,
 240                                     unsigned int num_params);
 241
 242 extern void module_param_sysfs_remove(struct module *mod);
 243 #else
 244 static inline int module_param_sysfs_setup(struct module *mod,
 245                              struct kernel_param *kparam,
 246                              unsigned int num_params)
 247 {
 248         return 0;
 249 }
 250
 251 static inline void module_param_sysfs_remove(struct module *mod)
 252 { }
 253 #endif
 254
 255 #endif /* _LINUX_MODULE_PARAMS_H */