commit 026cee0086fe1df4cf74691cf273062cc769617d
author Pawel Moll <pawel.moll@arm.com> Mon Mar 26 12:50:51 2012 +1030
committer Rusty Russell <rusty@rustcorp.com.au> Mon Mar 26 12:50:51 2012 +1030
tree 22735ecd2132de4570fbad81e5716f7fee3448d5
parent 8b8252813dee8e8cd453bb219731c36b268c69a7

params: <level>_initcall-like kernel parameters

This patch adds a set of macros that can be used to declare
kernel parameters to be parsed _before_ initcalls at a chosen
level are executed.  We rename the now-unused "flags" field of
struct kernel_param as the level.  It's signed, for when we
use this for early params as well, in future.

Linker macro collating init calls had to be modified in order
to add additional symbols between levels that are later used
by the init code to split the calls into blocks.

Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

include/linux/moduleparam.h

diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
index 4daa895..ea36486 100644
--- a/include/linux/moduleparam.h
+++ b/include/linux/moduleparam.h
@@ -51,7 +51,7 @@
 	const char *name;
 	const struct kernel_param_ops *ops;
 	u16 perm;
-	u16 flags;
+	s16 level;
 	union {
 		void *arg;
 		const struct kparam_string *str;
@@ -128,7 +128,40 @@
  * 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, perm)
+	__module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, 0)
+
+/**
+ * <level>_param_cb - general callback for a module/cmdline parameter
+ *                    to be evaluated before certain initcall level
+ * @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 __level_param_cb(name, ops, arg, perm, level)			\
+	__module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level)
+
+#define core_param_cb(name, ops, arg, perm)		\
+	__level_param_cb(name, ops, arg, perm, 1)
+
+#define postcore_param_cb(name, ops, arg, perm)		\
+	__level_param_cb(name, ops, arg, perm, 2)
+
+#define arch_param_cb(name, ops, arg, perm)		\
+	__level_param_cb(name, ops, arg, perm, 3)
+
+#define subsys_param_cb(name, ops, arg, perm)		\
+	__level_param_cb(name, ops, arg, perm, 4)
+
+#define fs_param_cb(name, ops, arg, perm)		\
+	__level_param_cb(name, ops, arg, perm, 5)
+
+#define device_param_cb(name, ops, arg, perm)		\
+	__level_param_cb(name, ops, arg, perm, 6)
+
+#define late_param_cb(name, ops, arg, perm)		\
+	__level_param_cb(name, ops, arg, perm, 7)
 
 /* On alpha, ia64 and ppc64 relocations to global data cannot go into
    read-only sections (which is part of respective UNIX ABI on these
@@ -142,7 +175,7 @@
 
 /* This is the fundamental function for registering boot/module
    parameters. */
-#define __module_param_call(prefix, name, ops, arg, perm)		\
+#define __module_param_call(prefix, name, ops, arg, perm, level)	\
 	/* Default value instead of permissions? */			\
 	static int __param_perm_check_##name __attribute__((unused)) =	\
 	BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2))	\
@@ -151,7 +184,7 @@
 	static struct kernel_param __moduleparam_const __param_##name	\
 	__used								\
     __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
-	= { __param_str_##name, ops, perm, 0, { arg } }
+	= { __param_str_##name, ops, perm, level, { arg } }
 
 /* Obsolete - use module_param_cb() */
 #define module_param_call(name, set, get, arg, perm)			\
@@ -159,7 +192,7 @@
 		 { (void *)set, (void *)get };				\
 	__module_param_call(MODULE_PARAM_PREFIX,			\
 			    name, &__param_ops_##name, arg,		\
-			    (perm) + sizeof(__check_old_set_param(set))*0)
+			    (perm) + sizeof(__check_old_set_param(set))*0, 0)
 
 /* We don't get oldget: it's often a new-style param_get_uint, etc. */
 static inline int
@@ -239,7 +272,7 @@
  */
 #define core_param(name, var, type, perm)				\
 	param_check_##type(name, &(var));				\
-	__module_param_call("", name, &param_ops_##type, &var, perm)
+	__module_param_call("", name, &param_ops_##type, &var, perm, 0)
 #endif /* !MODULE */
 
 /**
@@ -257,7 +290,7 @@
 		= { len, string };					\
 	__module_param_call(MODULE_PARAM_PREFIX, name,			\
 			    &param_ops_string,				\
-			    .str = &__param_string_##name, perm);	\
+			    .str = &__param_string_##name, perm, 0);	\
 	__MODULE_PARM_TYPE(name, "string")
 
 /**
@@ -285,6 +318,8 @@
 		      char *args,
 		      const struct kernel_param *params,
 		      unsigned num,
+		      s16 level_min,
+		      s16 level_max,
 		      int (*unknown)(char *param, char *val));
 
 /* Called by module remove. */
@@ -396,7 +431,7 @@
 	__module_param_call(MODULE_PARAM_PREFIX, name,			\
 			    &param_array_ops,				\
 			    .arr = &__param_arr_##name,			\
-			    perm);					\
+			    perm, 0);					\
 	__MODULE_PARM_TYPE(name, "array of " #type)
 
 extern struct kernel_param_ops param_array_ops;