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>
diff --git a/kernel/params.c b/kernel/params.c
index 508828a..f37d826 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -87,6 +87,8 @@
 		     char *val,
 		     const struct kernel_param *params,
 		     unsigned num_params,
+		     s16 min_level,
+		     s16 max_level,
 		     int (*handle_unknown)(char *param, char *val))
 {
 	unsigned int i;
@@ -95,6 +97,9 @@
 	/* Find parameter */
 	for (i = 0; i < num_params; i++) {
 		if (parameq(param, params[i].name)) {
+			if (params[i].level < min_level
+			    || params[i].level > max_level)
+				return 0;
 			/* No one handled NULL, so do it here. */
 			if (!val && params[i].ops->set != param_set_bool
 			    && params[i].ops->set != param_set_bint)
@@ -174,6 +179,8 @@
 	       char *args,
 	       const struct kernel_param *params,
 	       unsigned num,
+	       s16 min_level,
+	       s16 max_level,
 	       int (*unknown)(char *param, char *val))
 {
 	char *param, *val;
@@ -189,7 +196,8 @@
 
 		args = next_arg(args, &param, &val);
 		irq_was_disabled = irqs_disabled();
-		ret = parse_one(param, val, params, num, unknown);
+		ret = parse_one(param, val, params, num,
+				min_level, max_level, unknown);
 		if (irq_was_disabled && !irqs_disabled()) {
 			printk(KERN_WARNING "parse_args(): option '%s' enabled "
 					"irq's!\n", param);
@@ -374,7 +382,7 @@
 		       unsigned int min, unsigned int max,
 		       void *elem, int elemsize,
 		       int (*set)(const char *, const struct kernel_param *kp),
-		       u16 flags,
+		       s16 level,
 		       unsigned int *num)
 {
 	int ret;
@@ -384,7 +392,7 @@
 	/* Get the name right for errors. */
 	kp.name = name;
 	kp.arg = elem;
-	kp.flags = flags;
+	kp.level = level;
 
 	*num = 0;
 	/* We expect a comma-separated list of values. */
@@ -425,7 +433,7 @@
 	unsigned int temp_num;
 
 	return param_array(kp->name, val, 1, arr->max, arr->elem,
-			   arr->elemsize, arr->ops->set, kp->flags,
+			   arr->elemsize, arr->ops->set, kp->level,
 			   arr->num ?: &temp_num);
 }