1 files changed, 24 insertions, 1 deletions

diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
index ec624381c844..e4af3399ef48 100644
--- a/include/linux/moduleparam.h
+++ b/include/linux/moduleparam.h
@@ -13,6 +13,9 @@
 #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))
+
 #ifdef MODULE
 #define ___module_cat(a,b) __mod_ ## a ## b
 #define __module_cat(a,b) ___module_cat(a,b)
@@ -79,7 +82,8 @@ struct kparam_array
 #define __module_param_call(prefix, name, set, get, arg, 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((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                                                          \
@@ -100,6 +104,25 @@ struct kparam_array
 #define module_param(name, type, perm)                          \
         module_param_named(name, name, type, perm)
 
+#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 (for param_set_##type and param_get_##type)
+ * @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, param_set_##type, param_get_##type, \
+                            &var, perm)
+#endif /* !MODULE */
+
 /* Actually copy string: maxlen param is usually sizeof(string). */
 #define module_param_string(name, string, len, perm)                    \
         static const struct kparam_string __param_string_##name         \