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