resync with 4.19

Signed-off-by: Tom Rini <trini@konsulko.com>

36 files changed, 418 insertions, 56 deletions

diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile
index abc34f60d15..4be95c7ac57 100644
--- a/scripts/kconfig/Makefile
+++ b/scripts/kconfig/Makefile
@@ -50,7 +50,7 @@ build_xconfig: $(obj)/qconf
 
 localyesconfig localmodconfig: $(obj)/conf
 	$(Q)perl $(srctree)/$(src)/streamline_config.pl --$@ $(srctree) $(Kconfig) > .tmp.config
-	$(Q)if [ -f .config ]; then					\
+	$(Q)if [ -f .config ]; then 					\
 			cmp -s .tmp.config .config ||			\
 			(mv -f .config .config.old.1;			\
 			 mv -f .tmp.config .config;			\
@@ -74,7 +74,21 @@ PHONY += $(simple-targets)
 $(simple-targets): $(obj)/conf
 	$< $(silent) --$@ $(Kconfig)
 
-PHONY += savedefconfig defconfig
+PHONY += oldnoconfig silentoldconfig savedefconfig defconfig
+
+# oldnoconfig is an alias of olddefconfig, because people already are dependent
+# on its behavior (sets new symbols to their default value but not 'n') with the
+# counter-intuitive name.
+oldnoconfig: olddefconfig
+	@echo "  WARNING: \"oldnoconfig\" target will be removed after Linux 4.19"
+	@echo "            Please use \"olddefconfig\" instead, which is an alias."
+
+# We do not expect manual invokcation of "silentoldcofig" (or "syncconfig").
+silentoldconfig: syncconfig
+	@echo "  WARNING: \"silentoldconfig\" has been renamed to \"syncconfig\""
+	@echo "            and is now an internal implementation detail."
+	@echo "            What you want is probably \"oldconfig\"."
+	@echo "            \"silentoldconfig\" will be removed after Linux 4.19"
 
 savedefconfig: $(obj)/conf
 	$< $(silent) --$@=defconfig $(Kconfig)
diff --git a/scripts/kconfig/conf.c b/scripts/kconfig/conf.c
index 376f796f674..7b2b3726066 100644
--- a/scripts/kconfig/conf.c
+++ b/scripts/kconfig/conf.c
@@ -460,6 +460,12 @@ static struct option long_opts[] = {
 	{"randconfig",      no_argument,       NULL, randconfig},
 	{"listnewconfig",   no_argument,       NULL, listnewconfig},
 	{"olddefconfig",    no_argument,       NULL, olddefconfig},
+	/*
+	 * oldnoconfig is an alias of olddefconfig, because people already
+	 * are dependent on its behavior(sets new symbols to their default
+	 * value but not 'n') with the counter-intuitive name.
+	 */
+	{"oldnoconfig",     no_argument,       NULL, olddefconfig},
 	{NULL, 0, NULL, 0}
 };
 
@@ -474,6 +480,7 @@ static void conf_usage(const char *progname)
 	printf("  --syncconfig            Similar to oldconfig but generates configuration in\n"
 	       "                          include/{generated/,config/}\n");
 	printf("  --olddefconfig          Same as oldconfig but sets new symbols to their default value\n");
+	printf("  --oldnoconfig           An alias of olddefconfig\n");
 	printf("  --defconfig <file>      New config with default defined in <file>\n");
 	printf("  --savedefconfig <file>  Save the minimal current configuration to <file>\n");
 	printf("  --allnoconfig           New config where all options are answered with no\n");
@@ -684,29 +691,32 @@ int main(int ac, char **av)
 		break;
 	}
 
-	if (sync_kconfig) {
-		/* syncconfig is used during the build so we shall update autoconf.
-		 * All other commands are only used to generate a config.
-		 */
-		if (!no_conf_write && conf_write(NULL)) {
-			fprintf(stderr, "\n*** Error during writing of the configuration.\n\n");
-			exit(1);
-		}
-		if (conf_write_autoconf()) {
-			fprintf(stderr, "\n*** Error during update of the configuration.\n\n");
-			return 1;
-		}
-	} else if (input_mode == savedefconfig) {
+	if (input_mode == savedefconfig) {
 		if (conf_write_defconfig(defconfig_file)) {
 			fprintf(stderr, "n*** Error while saving defconfig to: %s\n\n",
 				defconfig_file);
 			return 1;
 		}
 	} else if (input_mode != listnewconfig) {
-		if (conf_write(NULL)) {
+		if (!no_conf_write && conf_write(NULL)) {
 			fprintf(stderr, "\n*** Error during writing of the configuration.\n\n");
 			exit(1);
 		}
+
+		/*
+		 * Create auto.conf if it does not exist.
+		 * This prevents GNU Make 4.1 or older from emitting
+		 * "include/config/auto.conf: No such file or directory"
+		 * in the top-level Makefile
+		 *
+		 * syncconfig always creates or updates auto.conf because it is
+		 * used during the build.
+		 */
+		if (conf_write_autoconf(sync_kconfig) && sync_kconfig) {
+			fprintf(stderr,
+				"\n*** Error during sync of the configuration.\n\n");
+			return 1;
+		}
 	}
 	return 0;
 }
diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index d587b10d7f8..91d0a5c014a 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -197,14 +197,18 @@ static int conf_set_sym_val(struct symbol *sym, int def, int def_flags, char *p)
 	case S_STRING:
 		if (*p++ != '"')
 			break;
-		/* Last char has to be a '"' */
-		if (p[strlen(p) - 1] != '"') {
+		for (p2 = p; (p2 = strpbrk(p2, "\"\\")); p2++) {
+			if (*p2 == '"') {
+				*p2 = 0;
+				break;
+			}
+			memmove(p2, p2 + 1, strlen(p2));
+		}
+		if (!p2) {
 			if (def != S_DEF_AUTO)
 				conf_warning("invalid string found");
 			return 1;
 		}
-		/* Overwrite '"' with \0 for string termination */
-		p[strlen(p) - 1] = 0;
 		/* fall through */
 	case S_INT:
 	case S_HEX:
@@ -663,7 +667,6 @@ static void conf_write_symbol(FILE *fp, struct symbol *sym,
 			      struct conf_printer *printer, void *printer_arg)
 {
 	const char *str;
-	char *str2;
 
 	switch (sym->type) {
 	case S_OTHER:
@@ -671,10 +674,9 @@ static void conf_write_symbol(FILE *fp, struct symbol *sym,
 		break;
 	case S_STRING:
 		str = sym_get_string_value(sym);
-		str2 = xmalloc(strlen(str) + 3);
-		sprintf(str2, "\"%s\"", str);
-		printer->print_symbol(fp, sym, str2, printer_arg);
-		free((void *)str2);
+		str = sym_escape_string_value(str);
+		printer->print_symbol(fp, sym, str, printer_arg);
+		free((void *)str);
 		break;
 	default:
 		str = sym_get_string_value(sym);
@@ -1011,13 +1013,17 @@ out:
 	return res;
 }
 
-int conf_write_autoconf(void)
+int conf_write_autoconf(int overwrite)
 {
 	struct symbol *sym;
 	const char *name;
+	const char *autoconf_name = conf_get_autoconfig_name();
 	FILE *out, *tristate, *out_h;
 	int i;
 
+	if (!overwrite && is_present(autoconf_name))
+		return 0;
+
 	sym_clear_all_valid();
 
 	conf_write_dep("include/config/auto.conf.cmd");
@@ -1080,14 +1086,13 @@ int conf_write_autoconf(void)
 	if (rename(".tmpconfig_tristate", name))
 		return 1;
 
-	name = conf_get_autoconfig_name();
-	if (make_parent_dir(name))
+	if (make_parent_dir(autoconf_name))
 		return 1;
 	/*
 	 * This must be the last step, kbuild has a dependency on auto.conf
 	 * and this marks the successful completion of the previous steps.
 	 */
-	if (rename(".tmpconfig", name))
+	if (rename(".tmpconfig", autoconf_name))
 		return 1;
 
 	return 0;
diff --git a/scripts/kconfig/expr.c b/scripts/kconfig/expr.c
index 9f79bdfaaa5..e1a39e90841 100644
--- a/scripts/kconfig/expr.c
+++ b/scripts/kconfig/expr.c
@@ -894,7 +894,7 @@ bool expr_depends_symbol(struct expr *dep, struct symbol *sym)
 	default:
 		;
 	}
-	return false;
+ 	return false;
 }
 
 /*
diff --git a/scripts/kconfig/gconf.c b/scripts/kconfig/gconf.c
index aee993a778f..36f578415c4 100644
--- a/scripts/kconfig/gconf.c
+++ b/scripts/kconfig/gconf.c
@@ -360,8 +360,10 @@ void init_right_tree(void)
 	gtk_tree_selection_set_mode(sel, GTK_SELECTION_SINGLE);
 }
 
+
 /* Utility Functions */
 
+
 static void text_insert_help(struct menu *menu)
 {
 	GtkTextBuffer *buffer;
@@ -386,6 +388,7 @@ static void text_insert_help(struct menu *menu)
 	str_free(&help);
 }
 
+
 static void text_insert_msg(const char *title, const char *message)
 {
 	GtkTextBuffer *buffer;
@@ -406,6 +409,7 @@ static void text_insert_msg(const char *title, const char *message)
 					 NULL);
 }
 
+
 /* Main Windows Callbacks */
 
 void on_save_activate(GtkMenuItem * menuitem, gpointer user_data);
@@ -453,11 +457,13 @@ gboolean on_window1_delete_event(GtkWidget * widget, GdkEvent * event,
 	return FALSE;
 }
 
+
 void on_window1_destroy(GtkObject * object, gpointer user_data)
 {
 	gtk_main_quit();
 }
 
+
 void
 on_window1_size_request(GtkWidget * widget,
 			GtkRequisition * requisition, gpointer user_data)
@@ -477,8 +483,10 @@ on_window1_size_request(GtkWidget * widget,
 	gtk_paned_set_position(GTK_PANED(vpaned), 2 * h / 3);
 }
 
+
 /* Menu & Toolbar Callbacks */
 
+
 static void
 load_filename(GtkFileSelection * file_selector, gpointer user_data)
 {
@@ -512,12 +520,15 @@ void on_load1_activate(GtkMenuItem * menuitem, gpointer user_data)
 	gtk_widget_show(fs);
 }
 
+
 void on_save_activate(GtkMenuItem * menuitem, gpointer user_data)
 {
 	if (conf_write(NULL))
 		text_insert_msg("Error", "Unable to save configuration !");
+	conf_write_autoconf(0);
 }
 
+
 static void
 store_filename(GtkFileSelection * file_selector, gpointer user_data)
 {
@@ -551,12 +562,14 @@ void on_save_as1_activate(GtkMenuItem * menuitem, gpointer user_data)
 	gtk_widget_show(fs);
 }
 
+
 void on_quit1_activate(GtkMenuItem * menuitem, gpointer user_data)
 {
 	if (!on_window1_delete_event(NULL, NULL, NULL))
 		gtk_widget_destroy(GTK_WIDGET(main_wnd));
 }
 
+
 void on_show_name1_activate(GtkMenuItem * menuitem, gpointer user_data)
 {
 	GtkTreeViewColumn *col;
@@ -567,6 +580,7 @@ void on_show_name1_activate(GtkMenuItem * menuitem, gpointer user_data)
 		gtk_tree_view_column_set_visible(col, show_name);
 }
 
+
 void on_show_range1_activate(GtkMenuItem * menuitem, gpointer user_data)
 {
 	GtkTreeViewColumn *col;
@@ -584,6 +598,7 @@ void on_show_range1_activate(GtkMenuItem * menuitem, gpointer user_data)
 
 }
 
+
 void on_show_data1_activate(GtkMenuItem * menuitem, gpointer user_data)
 {
 	GtkTreeViewColumn *col;
@@ -594,6 +609,7 @@ void on_show_data1_activate(GtkMenuItem * menuitem, gpointer user_data)
 		gtk_tree_view_column_set_visible(col, show_value);
 }
 
+
 void
 on_set_option_mode1_activate(GtkMenuItem *menuitem, gpointer user_data)
 {
@@ -602,6 +618,7 @@ on_set_option_mode1_activate(GtkMenuItem *menuitem, gpointer user_data)
 	display_tree(&rootmenu);	/* instead of update_tree to speed-up */
 }
 
+
 void
 on_set_option_mode2_activate(GtkMenuItem *menuitem, gpointer user_data)
 {
@@ -610,6 +627,7 @@ on_set_option_mode2_activate(GtkMenuItem *menuitem, gpointer user_data)
 	display_tree(&rootmenu);	/* instead of update_tree to speed-up */
 }
 
+
 void
 on_set_option_mode3_activate(GtkMenuItem *menuitem, gpointer user_data)
 {
@@ -618,10 +636,11 @@ on_set_option_mode3_activate(GtkMenuItem *menuitem, gpointer user_data)
 	display_tree(&rootmenu);	/* instead of update_tree to speed-up */
 }
 
+
 void on_introduction1_activate(GtkMenuItem * menuitem, gpointer user_data)
 {
 	GtkWidget *dialog;
-	const gchar *intro_text =
+	const gchar *intro_text = 
 	    "Welcome to gkc, the GTK+ graphical configuration tool\n"
 	    "For each option, a blank box indicates the feature is disabled, a\n"
 	    "check indicates it is enabled, and a dot indicates that it is to\n"
@@ -648,6 +667,7 @@ void on_introduction1_activate(GtkMenuItem * menuitem, gpointer user_data)
 	gtk_widget_show_all(dialog);
 }
 
+
 void on_about1_activate(GtkMenuItem * menuitem, gpointer user_data)
 {
 	GtkWidget *dialog;
@@ -665,6 +685,7 @@ void on_about1_activate(GtkMenuItem * menuitem, gpointer user_data)
 	gtk_widget_show_all(dialog);
 }
 
+
 void on_license1_activate(GtkMenuItem * menuitem, gpointer user_data)
 {
 	GtkWidget *dialog;
@@ -683,6 +704,7 @@ void on_license1_activate(GtkMenuItem * menuitem, gpointer user_data)
 	gtk_widget_show_all(dialog);
 }
 
+
 void on_back_clicked(GtkButton * button, gpointer user_data)
 {
 	enum prop_type ptype;
@@ -697,11 +719,13 @@ void on_back_clicked(GtkButton * button, gpointer user_data)
 		gtk_widget_set_sensitive(back_btn, FALSE);
 }
 
+
 void on_load_clicked(GtkButton * button, gpointer user_data)
 {
 	on_load1_activate(NULL, user_data);
 }
 
+
 void on_single_clicked(GtkButton * button, gpointer user_data)
 {
 	view_mode = SINGLE_VIEW;
@@ -710,6 +734,7 @@ void on_single_clicked(GtkButton * button, gpointer user_data)
 	display_tree_part();
 }
 
+
 void on_split_clicked(GtkButton * button, gpointer user_data)
 {
 	gint w, h;
@@ -725,6 +750,7 @@ void on_split_clicked(GtkButton * button, gpointer user_data)
 	gtk_widget_set_sensitive(back_btn, FALSE);
 }
 
+
 void on_full_clicked(GtkButton * button, gpointer user_data)
 {
 	view_mode = FULL_VIEW;
@@ -735,16 +761,19 @@ void on_full_clicked(GtkButton * button, gpointer user_data)
 	gtk_widget_set_sensitive(back_btn, FALSE);
 }
 
+
 void on_collapse_clicked(GtkButton * button, gpointer user_data)
 {
 	gtk_tree_view_collapse_all(GTK_TREE_VIEW(tree2_w));
 }
 
+
 void on_expand_clicked(GtkButton * button, gpointer user_data)
 {
 	gtk_tree_view_expand_all(GTK_TREE_VIEW(tree2_w));
 }
 
+
 /* CTree Callbacks */
 
 /* Change hex/int/string value in the cell */
@@ -846,6 +875,7 @@ static gint column2index(GtkTreeViewColumn * column)
 	return -1;
 }
 
+
 /* User click: update choice (full) or goes down (single) */
 gboolean
 on_treeview2_button_press_event(GtkWidget * widget,
@@ -947,6 +977,7 @@ on_treeview2_key_press_event(GtkWidget * widget,
 	return FALSE;
 }
 
+
 /* Row selection changed: update help */
 void
 on_treeview2_cursor_changed(GtkTreeView * treeview, gpointer user_data)
@@ -962,6 +993,7 @@ on_treeview2_cursor_changed(GtkTreeView * treeview, gpointer user_data)
 	}
 }
 
+
 /* User click: display sub-tree in the right frame. */
 gboolean
 on_treeview1_button_press_event(GtkWidget * widget,
@@ -1001,6 +1033,7 @@ on_treeview1_button_press_event(GtkWidget * widget,
 	return FALSE;
 }
 
+
 /* Fill a row of strings */
 static gchar **fill_row(struct menu *menu)
 {
@@ -1125,6 +1158,7 @@ static gchar **fill_row(struct menu *menu)
 	return row;
 }
 
+
 /* Set the node content with a row of strings */
 static void set_node(GtkTreeIter * node, struct menu *menu, gchar ** row)
 {
@@ -1160,6 +1194,7 @@ static void set_node(GtkTreeIter * node, struct menu *menu, gchar ** row)
 	g_object_unref(pix);
 }
 
+
 /* Add a node to the tree */
 static void place_node(struct menu *menu, char **row)
 {
@@ -1170,6 +1205,7 @@ static void place_node(struct menu *menu, char **row)
 	set_node(node, menu, row);
 }
 
+
 /* Find a node in the GTK+ tree */
 static GtkTreeIter found;
 
@@ -1205,6 +1241,7 @@ GtkTreeIter *gtktree_iter_find_node(GtkTreeIter * parent,
 	return NULL;
 }
 
+
 /*
  * Update the tree by adding/removing entries
  * Does not change other nodes
@@ -1293,6 +1330,7 @@ static void update_tree(struct menu *src, GtkTreeIter * dst)
 	}
 }
 
+
 /* Display the whole tree (single/split/full view) */
 static void display_tree(struct menu *menu)
 {
@@ -1402,6 +1440,7 @@ void fixup_rootmenu(struct menu *menu)
 	}
 }
 
+
 /* Main */
 int main(int ac, char *av[])
 {
diff --git a/scripts/kconfig/list.h b/scripts/kconfig/list.h
index 9f1d16a43c2..45cb237ab7e 100644
--- a/scripts/kconfig/list.h
+++ b/scripts/kconfig/list.h
@@ -20,10 +20,12 @@
 	const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
 	(type *)( (char *)__mptr - offsetof(type,member) );})
 
+
 struct list_head {
 	struct list_head *next, *prev;
 };
 
+
 #define LIST_HEAD_INIT(name) { &(name), &(name) }
 
 #define LIST_HEAD(name) \
@@ -46,7 +48,7 @@ struct list_head {
  */
 #define list_for_each_entry(pos, head, member)				\
 	for (pos = list_entry((head)->next, typeof(*pos), member);	\
-	     &pos->member != (head);	\
+	     &pos->member != (head); 	\
 	     pos = list_entry(pos->member.next, typeof(*pos), member))
 
 /**
diff --git a/scripts/kconfig/lkc.h b/scripts/kconfig/lkc.h
index 2daf47f57cc..9eb7c837cd8 100644
--- a/scripts/kconfig/lkc.h
+++ b/scripts/kconfig/lkc.h
@@ -131,6 +131,7 @@ static inline tristate sym_get_tristate_value(struct symbol *sym)
 	return sym->curr.tri;
 }
 
+
 static inline struct symbol *sym_get_choice_value(struct symbol *sym)
 {
 	return (struct symbol *)sym->curr.val;
diff --git a/scripts/kconfig/lkc_proto.h b/scripts/kconfig/lkc_proto.h
index cf4510a2bdc..86c267540cc 100644
--- a/scripts/kconfig/lkc_proto.h
+++ b/scripts/kconfig/lkc_proto.h
@@ -7,7 +7,7 @@ int conf_read(const char *name);
 int conf_read_simple(const char *name, int);
 int conf_write_defconfig(const char *name);
 int conf_write(const char *name);
-int conf_write_autoconf(void);
+int conf_write_autoconf(int overwrite);
 bool conf_get_changed(void);
 void conf_set_changed_callback(void (*fn)(void));
 void conf_set_message_callback(void (*fn)(const char *s));
diff --git a/scripts/kconfig/lxdialog/checklist.c b/scripts/kconfig/lxdialog/checklist.c
index fd161cfff12..2e96323ad11 100644
--- a/scripts/kconfig/lxdialog/checklist.c
+++ b/scripts/kconfig/lxdialog/checklist.c
@@ -1,4 +1,3 @@
-// SPDX-License-Identifier: GPL-2.0+
 /*
  *  checklist.c -- implements the checklist box
  *
@@ -6,6 +5,20 @@
  *     Stuart Herbert - S.Herbert@sheffield.ac.uk: radiolist extension
  *     Alessandro Rubini - rubini@ipvvis.unipv.it: merged the two
  *  MODIFIED FOR LINUX KERNEL CONFIG BY: William Roadcap (roadcap@cfw.com)
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version 2
+ *  of the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
 #include "dialog.h"
diff --git a/scripts/kconfig/lxdialog/dialog.h b/scripts/kconfig/lxdialog/dialog.h
index 7675c4702ac..0b00be5abaa 100644
--- a/scripts/kconfig/lxdialog/dialog.h
+++ b/scripts/kconfig/lxdialog/dialog.h
@@ -1,8 +1,21 @@
-/* SPDX-License-Identifier: GPL-2.0+ */
 /*
  *  dialog.h -- common declarations for all dialog modules
  *
  *  AUTHOR: Savio Lam (lam836@cs.cuhk.hk)
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version 2
+ *  of the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
 #include <sys/types.h>
@@ -213,6 +226,7 @@ int dialog_yesno(const char *title, const char *prompt, int height, int width);
 int dialog_msgbox(const char *title, const char *prompt, int height,
 		  int width, int pause);
 
+
 typedef void (*update_text_fn)(char *buf, size_t start, size_t end, void
 			       *_data);
 int dialog_textbox(const char *title, char *tbuf, int initial_height,
diff --git a/scripts/kconfig/lxdialog/inputbox.c b/scripts/kconfig/lxdialog/inputbox.c
index 611945611bf..fe82ff6d744 100644
--- a/scripts/kconfig/lxdialog/inputbox.c
+++ b/scripts/kconfig/lxdialog/inputbox.c
@@ -1,9 +1,22 @@
-// SPDX-License-Identifier: GPL-2.0+
 /*
  *  inputbox.c -- implements the input box
  *
  *  ORIGINAL AUTHOR: Savio Lam (lam836@cs.cuhk.hk)
  *  MODIFIED FOR LINUX KERNEL CONFIG BY: William Roadcap (roadcap@cfw.com)
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version 2
+ *  of the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
 #include "dialog.h"
diff --git a/scripts/kconfig/lxdialog/menubox.c b/scripts/kconfig/lxdialog/menubox.c
index 58c2f8afe59..d70cab36137 100644
--- a/scripts/kconfig/lxdialog/menubox.c
+++ b/scripts/kconfig/lxdialog/menubox.c
@@ -1,9 +1,22 @@
-// SPDX-License-Identifier: GPL-2.0+
 /*
  *  menubox.c -- implements the menu box
  *
  *  ORIGINAL AUTHOR: Savio Lam (lam836@cs.cuhk.hk)
  *  MODIFIED FOR LINUX KERNEL CONFIG BY: William Roadcap (roadcapw@cfw.com)
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version 2
+ *  of the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
 /*
diff --git a/scripts/kconfig/lxdialog/textbox.c b/scripts/kconfig/lxdialog/textbox.c
index 12e68c0fb64..88d2818ed95 100644
--- a/scripts/kconfig/lxdialog/textbox.c
+++ b/scripts/kconfig/lxdialog/textbox.c
@@ -1,9 +1,22 @@
-// SPDX-License-Identifier: GPL-2.0+
 /*
  *  textbox.c -- implements the text box
  *
  *  ORIGINAL AUTHOR: Savio Lam (lam836@cs.cuhk.hk)
  *  MODIFIED FOR LINUX KERNEL CONFIG BY: William Roadcap (roadcap@cfw.com)
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version 2
+ *  of the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
 #include "dialog.h"
@@ -33,6 +46,7 @@ static void refresh_text_box(WINDOW *dialog, WINDOW *box, int boxh, int boxw,
 	wrefresh(dialog);
 }
 
+
 /*
  * Display text from a file in a dialog box.
  *
diff --git a/scripts/kconfig/lxdialog/util.c b/scripts/kconfig/lxdialog/util.c
index 1b490d4af0d..f7abdeb92af 100644
--- a/scripts/kconfig/lxdialog/util.c
+++ b/scripts/kconfig/lxdialog/util.c
@@ -1,9 +1,22 @@
-// SPDX-License-Identifier: GPL-2.0+
 /*
  *  util.c
  *
  *  ORIGINAL AUTHOR: Savio Lam (lam836@cs.cuhk.hk)
  *  MODIFIED FOR LINUX KERNEL CONFIG BY: William Roadcap (roadcap@cfw.com)
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version 2
+ *  of the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
 #include <stdarg.h>
diff --git a/scripts/kconfig/lxdialog/yesno.c b/scripts/kconfig/lxdialog/yesno.c
index bcaac9b7bab..cd1223c903d 100644
--- a/scripts/kconfig/lxdialog/yesno.c
+++ b/scripts/kconfig/lxdialog/yesno.c
@@ -1,9 +1,22 @@
-// SPDX-License-Identifier: GPL-2.0+
 /*
  *  yesno.c -- implements the yes/no box
  *
  *  ORIGINAL AUTHOR: Savio Lam (lam836@cs.cuhk.hk)
  *  MODIFIED FOR LINUX KERNEL CONFIG BY: William Roadcap (roadcap@cfw.com)
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version 2
+ *  of the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
 #include "dialog.h"
diff --git a/scripts/kconfig/mconf.c b/scripts/kconfig/mconf.c
index c1b38747c14..143c05fec16 100644
--- a/scripts/kconfig/mconf.c
+++ b/scripts/kconfig/mconf.c
@@ -973,6 +973,7 @@ static int handle_exit(void)
 					  "\n\n");
 			return 1;
 		}
+		conf_write_autoconf(0);
 		/* fall through */
 	case -1:
 		if (!silent)
diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c
index 0fe7f3255af..4cf15d449c0 100644
--- a/scripts/kconfig/menu.c
+++ b/scripts/kconfig/menu.c
@@ -853,6 +853,7 @@ struct gstr get_relations_str(struct symbol **sym_arr, struct list_head *head)
 	return res;
 }
 
+
 void menu_get_ext_help(struct menu *menu, struct gstr *help)
 {
 	struct symbol *sym = menu->sym;
diff --git a/scripts/kconfig/merge_config.sh b/scripts/kconfig/merge_config.sh
index 0ef90649964..67d13144763 100755
--- a/scripts/kconfig/merge_config.sh
+++ b/scripts/kconfig/merge_config.sh
@@ -33,15 +33,12 @@ usage() {
 	echo "  -n    use allnoconfig instead of alldefconfig"
 	echo "  -r    list redundant entries when merging fragments"
 	echo "  -O    dir to put generated output files.  Consider setting \$KCONFIG_CONFIG instead."
-	echo
-	echo "Used prefix: '$CONFIG_PREFIX'. You can redefine it with \$CONFIG_ environment variable."
 }
 
 RUNMAKE=true
 ALLTARGET=alldefconfig
 WARNREDUN=false
 OUTPUT=.
-CONFIG_PREFIX=${CONFIG_-CONFIG_}
 
 while true; do
 	case $1 in
@@ -102,9 +99,7 @@ if [ ! -r "$INITFILE" ]; then
 fi
 
 MERGE_LIST=$*
-SED_CONFIG_EXP1="s/^\(${CONFIG_PREFIX}[a-zA-Z0-9_]*\)=.*/\1/p"
-SED_CONFIG_EXP2="s/^# \(${CONFIG_PREFIX}[a-zA-Z0-9_]*\) is not set$/\1/p"
-
+SED_CONFIG_EXP="s/^\(# \)\{0,1\}\(CONFIG_[a-zA-Z0-9_]*\)[= ].*/\2/p"
 TMP_FILE=$(mktemp ./.tmp.config.XXXXXXXXXX)
 
 echo "Using $INITFILE as base"
@@ -117,7 +112,7 @@ for MERGE_FILE in $MERGE_LIST ; do
 		echo "The merge file '$MERGE_FILE' does not exist.  Exit." >&2
 		exit 1
 	fi
-	CFG_LIST=$(sed -n -e "$SED_CONFIG_EXP1" -e "$SED_CONFIG_EXP2" $MERGE_FILE)
+	CFG_LIST=$(sed -n "$SED_CONFIG_EXP" $MERGE_FILE)
 
 	for CFG in $CFG_LIST ; do
 		grep -q -w $CFG $TMP_FILE || continue
@@ -160,7 +155,7 @@ make KCONFIG_ALLCONFIG=$TMP_FILE $OUTPUT_ARG $ALLTARGET
 
 
 # Check all specified config values took (might have missed-dependency issues)
-for CFG in $(sed -n -e "$SED_CONFIG_EXP1" -e "$SED_CONFIG_EXP2" $TMP_FILE); do
+for CFG in $(sed -n "$SED_CONFIG_EXP" $TMP_FILE); do
 
 	REQUESTED_VAL=$(grep -w -e "$CFG" $TMP_FILE)
 	ACTUAL_VAL=$(grep -w -e "$CFG" "$KCONFIG_CONFIG")
diff --git a/scripts/kconfig/nconf.c b/scripts/kconfig/nconf.c
index ca878212f0a..1ef232ae5ab 100644
--- a/scripts/kconfig/nconf.c
+++ b/scripts/kconfig/nconf.c
@@ -674,6 +674,7 @@ static int do_exit(void)
 				  "Your configuration changes were NOT saved.",
 				  1,
 				  "<OK>");
+		conf_write_autoconf(0);
 		break;
 	default:
 		btn_dialog(
@@ -687,6 +688,7 @@ static int do_exit(void)
 	return 0;
 }
 
+
 static void search_conf(void)
 {
 	struct symbol **sym_arr;
@@ -730,6 +732,7 @@ again:
 	str_free(&title);
 }
 
+
 static void build_conf(struct menu *menu)
 {
 	struct symbol *sym;
diff --git a/scripts/kconfig/nconf.gui.c b/scripts/kconfig/nconf.gui.c
index 2a3b853e7ea..88874acfda3 100644
--- a/scripts/kconfig/nconf.gui.c
+++ b/scripts/kconfig/nconf.gui.c
@@ -143,6 +143,7 @@ void set_colors(void)
 	}
 }
 
+
 /* this changes the windows attributes !!! */
 void print_in_middle(WINDOW *win,
 		int starty,
@@ -153,6 +154,7 @@ void print_in_middle(WINDOW *win,
 {      int length, x, y;
 	float temp;
 
+
 	if (win == NULL)
 		win = stdscr;
 	getyx(win, y, x);
@@ -254,6 +256,7 @@ int btn_dialog(WINDOW *main_window, const char *msg, int btn_num, ...)
 	int i, x, y;
 	int res = -1;
 
+
 	va_start(ap, btn_num);
 	for (i = 0; i < btn_num; i++) {
 		btn = va_arg(ap, char *);
@@ -277,6 +280,7 @@ int btn_dialog(WINDOW *main_window, const char *msg, int btn_num, ...)
 	y = (getmaxy(stdscr)-(msg_lines+4))/2;
 	x = (getmaxx(stdscr)-(total_width+4))/2;
 
+
 	/* create the windows */
 	if (btn_num > 0)
 		win_rows = msg_lines+4;
@@ -311,6 +315,7 @@ int btn_dialog(WINDOW *main_window, const char *msg, int btn_num, ...)
 	set_menu_mark(menu, "");
 	post_menu(menu);
 
+
 	touchwin(win);
 	refresh_all_windows(main_window);
 	while ((res = wgetch(win))) {
diff --git a/scripts/kconfig/qconf.cc b/scripts/kconfig/qconf.cc
index 0c3fa940568..ef4310f2558 100644
--- a/scripts/kconfig/qconf.cc
+++ b/scripts/kconfig/qconf.cc
@@ -1534,6 +1534,8 @@ bool ConfigMainWindow::saveConfig(void)
 		QMessageBox::information(this, "qconf", "Unable to save configuration!");
 		return false;
 	}
+	conf_write_autoconf(0);
+
 	return true;
 }
 
diff --git a/scripts/kconfig/symbol.c b/scripts/kconfig/symbol.c
index 5245804bb33..703b9b899ee 100644
--- a/scripts/kconfig/symbol.c
+++ b/scripts/kconfig/symbol.c
@@ -1117,7 +1117,7 @@ static void sym_check_print_recursive(struct symbol *last_sym)
 	}
 
 	fprintf(stderr,
-		"For a resolution refer to Documentation/kbuild/kconfig-language.rst\n"
+		"For a resolution refer to Documentation/kbuild/kconfig-language.txt\n"
 		"subsection \"Kconfig recursive dependency limitations\"\n"
 		"\n");
 
diff --git a/scripts/kconfig/tests/err_recursive_dep/expected_stderr b/scripts/kconfig/tests/err_recursive_dep/expected_stderr
index c9f4abf9a79..84679b10465 100644
--- a/scripts/kconfig/tests/err_recursive_dep/expected_stderr
+++ b/scripts/kconfig/tests/err_recursive_dep/expected_stderr
@@ -1,38 +1,38 @@
 Kconfig:11:error: recursive dependency detected!
 Kconfig:11:	symbol B is selected by B
-For a resolution refer to Documentation/kbuild/kconfig-language.rst
+For a resolution refer to Documentation/kbuild/kconfig-language.txt
 subsection "Kconfig recursive dependency limitations"
 
 Kconfig:5:error: recursive dependency detected!
 Kconfig:5:	symbol A depends on A
-For a resolution refer to Documentation/kbuild/kconfig-language.rst
+For a resolution refer to Documentation/kbuild/kconfig-language.txt
 subsection "Kconfig recursive dependency limitations"
 
 Kconfig:17:error: recursive dependency detected!
 Kconfig:17:	symbol C1 depends on C2
 Kconfig:21:	symbol C2 depends on C1
-For a resolution refer to Documentation/kbuild/kconfig-language.rst
+For a resolution refer to Documentation/kbuild/kconfig-language.txt
 subsection "Kconfig recursive dependency limitations"
 
 Kconfig:32:error: recursive dependency detected!
 Kconfig:32:	symbol D2 is selected by D1
 Kconfig:27:	symbol D1 depends on D2
-For a resolution refer to Documentation/kbuild/kconfig-language.rst
+For a resolution refer to Documentation/kbuild/kconfig-language.txt
 subsection "Kconfig recursive dependency limitations"
 
 Kconfig:37:error: recursive dependency detected!
 Kconfig:37:	symbol E1 depends on E2
 Kconfig:42:	symbol E2 is implied by E1
-For a resolution refer to Documentation/kbuild/kconfig-language.rst
+For a resolution refer to Documentation/kbuild/kconfig-language.txt
 subsection "Kconfig recursive dependency limitations"
 
 Kconfig:60:error: recursive dependency detected!
 Kconfig:60:	symbol G depends on G
-For a resolution refer to Documentation/kbuild/kconfig-language.rst
+For a resolution refer to Documentation/kbuild/kconfig-language.txt
 subsection "Kconfig recursive dependency limitations"
 
 Kconfig:51:error: recursive dependency detected!
 Kconfig:51:	symbol F2 depends on F1
 Kconfig:49:	symbol F1 default value contains F2
-For a resolution refer to Documentation/kbuild/kconfig-language.rst
+For a resolution refer to Documentation/kbuild/kconfig-language.txt
 subsection "Kconfig recursive dependency limitations"
diff --git a/scripts/kconfig/tests/preprocess/builtin_func/Kconfig b/scripts/kconfig/tests/preprocess/builtin_func/Kconfig
new file mode 100644
index 00000000000..baa32882791
--- /dev/null
+++ b/scripts/kconfig/tests/preprocess/builtin_func/Kconfig
@@ -0,0 +1,27 @@
+# SPDX-License-Identifier: GPL-2.0
+
+# 'info' prints the argument to stdout.
+$(info,hello world 0)
+
+# 'warning-if', if the first argument is y, sends the second argument to stderr,
+# and the message is prefixed with the current file name and line number.
+$(warning-if,y,hello world 1)
+
+# 'error-if' is similar, but it terminates the parsing immediately.
+# The following is just no-op since the first argument is not y.
+$(error-if,n,this should not be printed)
+
+# Shorthand
+warning = $(warning-if,y,$(1))
+
+# 'shell' executes a command, and returns its stdout.
+$(warning,$(shell,echo hello world 3))
+
+# Every newline in the output is replaced with a space,
+# but any trailing newlines are deleted.
+$(warning,$(shell,printf 'hello\nworld\n\n4\n\n\n'))
+
+# 'filename' is expanded to the currently parsed file name,
+# 'lineno' to the line number.
+$(warning,filename=$(filename))
+$(warning,lineno=$(lineno))
diff --git a/scripts/kconfig/tests/preprocess/builtin_func/__init__.py b/scripts/kconfig/tests/preprocess/builtin_func/__init__.py
new file mode 100644
index 00000000000..2e53ba08fca
--- /dev/null
+++ b/scripts/kconfig/tests/preprocess/builtin_func/__init__.py
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0
+"""
+Built-in function tests.
+"""
+
+def test(conf):
+    assert conf.oldaskconfig() == 0
+    assert conf.stdout_contains('expected_stdout')
+    assert conf.stderr_matches('expected_stderr')
diff --git a/scripts/kconfig/tests/preprocess/builtin_func/expected_stderr b/scripts/kconfig/tests/preprocess/builtin_func/expected_stderr
new file mode 100644
index 00000000000..33ea9ca3840
--- /dev/null
+++ b/scripts/kconfig/tests/preprocess/builtin_func/expected_stderr
@@ -0,0 +1,5 @@
+Kconfig:8: hello world 1
+Kconfig:18: hello world 3
+Kconfig:22: hello world  4
+Kconfig:26: filename=Kconfig
+Kconfig:27: lineno=27
diff --git a/scripts/kconfig/tests/preprocess/builtin_func/expected_stdout b/scripts/kconfig/tests/preprocess/builtin_func/expected_stdout
new file mode 100644
index 00000000000..82de3a7e97d
--- /dev/null
+++ b/scripts/kconfig/tests/preprocess/builtin_func/expected_stdout
@@ -0,0 +1 @@
+hello world 0
diff --git a/scripts/kconfig/tests/preprocess/circular_expansion/Kconfig b/scripts/kconfig/tests/preprocess/circular_expansion/Kconfig
new file mode 100644
index 00000000000..6838997c23b
--- /dev/null
+++ b/scripts/kconfig/tests/preprocess/circular_expansion/Kconfig
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
+X = $(Y)
+Y = $(X)
+$(info $(X))
diff --git a/scripts/kconfig/tests/preprocess/circular_expansion/__init__.py b/scripts/kconfig/tests/preprocess/circular_expansion/__init__.py
new file mode 100644
index 00000000000..419bda3e075
--- /dev/null
+++ b/scripts/kconfig/tests/preprocess/circular_expansion/__init__.py
@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: GPL-2.0
+"""
+Detect circular variable expansion.
+
+If a recursively expanded variable references itself (eventually),
+it should fail with an error message.
+"""
+
+def test(conf):
+    assert conf.oldaskconfig() != 0
+    assert conf.stderr_matches('expected_stderr')
diff --git a/scripts/kconfig/tests/preprocess/circular_expansion/expected_stderr b/scripts/kconfig/tests/preprocess/circular_expansion/expected_stderr
new file mode 100644
index 00000000000..cde68fa989d
--- /dev/null
+++ b/scripts/kconfig/tests/preprocess/circular_expansion/expected_stderr
@@ -0,0 +1 @@
+Kconfig:5: Recursive variable 'X' references itself (eventually)
diff --git a/scripts/kconfig/tests/preprocess/escape/Kconfig b/scripts/kconfig/tests/preprocess/escape/Kconfig
new file mode 100644
index 00000000000..4e3f4444554
--- /dev/null
+++ b/scripts/kconfig/tests/preprocess/escape/Kconfig
@@ -0,0 +1,44 @@
+# SPDX-License-Identifier: GPL-2.0
+
+# Shorthand
+warning = $(warning-if,y,$(1))
+
+# You can not pass commas directly to a function since they are treated as
+# delimiters. You can use the following trick to do so.
+comma   := ,
+$(warning,hello$(comma) world)
+
+# Like Make, single quotes, double quotes, spaces are treated verbatim.
+# The following prints the text as-is.
+$(warning,  ' " '"   ' ''' "'")
+
+# Unlike Make, '$' has special meaning only when it is followed by '('.
+# No need to escape '$' itself.
+$(warning,$)
+$(warning,$$)
+$ := 1
+$(warning,$($))
+
+# You need a trick to escape '$' followed by '('
+# The following should print "$(X)". It should not be expanded further.
+dollar := $
+$(warning,$(dollar)(X))
+
+# You need a trick to treat unbalanced parentheses.
+# The following should print "(".
+left_paren := (
+$(warning,$(left_paren))
+
+# A simple expanded should not be expanded multiple times.
+# The following should print "$(X)". It should not be expanded further.
+Y := $(dollar)(X)
+$(warning,$(Y))
+
+# The following should print "$(X)" as well.
+Y = $(dollar)(X)
+$(warning,$(Y))
+
+# The following should print "$(".
+# It should not be emit "unterminated reference" error.
+unterminated := $(dollar)(
+$(warning,$(unterminated))
diff --git a/scripts/kconfig/tests/preprocess/escape/__init__.py b/scripts/kconfig/tests/preprocess/escape/__init__.py
new file mode 100644
index 00000000000..7ee8e747f54
--- /dev/null
+++ b/scripts/kconfig/tests/preprocess/escape/__init__.py
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0
+"""
+Escape sequence tests.
+"""
+
+def test(conf):
+    assert conf.oldaskconfig() == 0
+    assert conf.stderr_matches('expected_stderr')
diff --git a/scripts/kconfig/tests/preprocess/escape/expected_stderr b/scripts/kconfig/tests/preprocess/escape/expected_stderr
new file mode 100644
index 00000000000..1c00957ddaa
--- /dev/null
+++ b/scripts/kconfig/tests/preprocess/escape/expected_stderr
@@ -0,0 +1,10 @@
+Kconfig:9: hello, world
+Kconfig:13:   ' " '"   ' ''' "'"
+Kconfig:17: $
+Kconfig:18: $$
+Kconfig:20: 1
+Kconfig:25: $(X)
+Kconfig:30: (
+Kconfig:35: $(X)
+Kconfig:39: $(X)
+Kconfig:44: $(
diff --git a/scripts/kconfig/tests/preprocess/variable/Kconfig b/scripts/kconfig/tests/preprocess/variable/Kconfig
new file mode 100644
index 00000000000..9ce2f95cbd2
--- /dev/null
+++ b/scripts/kconfig/tests/preprocess/variable/Kconfig
@@ -0,0 +1,53 @@
+# SPDX-License-Identifier: GPL-2.0
+
+# Shorthand
+warning = $(warning-if,y,$(1))
+
+# Simply expanded variable.
+X := 1
+SIMPLE := $(X)
+X := 2
+$(warning,SIMPLE = $(SIMPLE))
+
+# Recursively expanded variable.
+X := 1
+RECURSIVE = $(X)
+X := 2
+$(warning,RECURSIVE = $(RECURSIVE))
+
+# Append something to a simply expanded variable.
+Y := 3
+SIMPLE += $(Y)
+Y := 4
+$(warning,SIMPLE = $(SIMPLE))
+
+# Append something to a recursively expanded variable.
+Y := 3
+RECURSIVE += $(Y)
+Y := 4
+$(warning,RECURSIVE = $(RECURSIVE))
+
+# Use += operator to an undefined variable.
+# This works as a recursively expanded variable.
+Y := 3
+UNDEFINED_VARIABLE += $(Y)
+Y := 4
+$(warning,UNDEFINED_VARIABLE = $(UNDEFINED_VARIABLE))
+
+# You can use variable references for the lefthand side of assignment statement.
+X := A
+Y := B
+$(X)$(Y) := 5
+$(warning,AB = $(AB))
+
+# User-defined function.
+greeting = $(1), my name is $(2).
+$(warning,$(greeting,Hello,John))
+
+# The number of arguments is not checked for user-defined functions.
+# If some arguments are optional, it is useful to pass fewer parameters.
+# $(2) will be blank in this case.
+$(warning,$(greeting,Hello))
+
+# Unreferenced parameters are just ignored.
+$(warning,$(greeting,Hello,John,ignored,ignored))
diff --git a/scripts/kconfig/tests/preprocess/variable/__init__.py b/scripts/kconfig/tests/preprocess/variable/__init__.py
new file mode 100644
index 00000000000..e88b1708d6d
--- /dev/null
+++ b/scripts/kconfig/tests/preprocess/variable/__init__.py
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0
+"""
+Variable and user-defined function tests.
+"""
+
+def test(conf):
+    assert conf.oldaskconfig() == 0
+    assert conf.stderr_matches('expected_stderr')
diff --git a/scripts/kconfig/tests/preprocess/variable/expected_stderr b/scripts/kconfig/tests/preprocess/variable/expected_stderr
new file mode 100644
index 00000000000..a4841c3fdff
--- /dev/null
+++ b/scripts/kconfig/tests/preprocess/variable/expected_stderr
@@ -0,0 +1,9 @@
+Kconfig:10: SIMPLE = 1
+Kconfig:16: RECURSIVE = 2
+Kconfig:22: SIMPLE = 1 3
+Kconfig:28: RECURSIVE = 2 4
+Kconfig:35: UNDEFINED_VARIABLE = 4
+Kconfig:41: AB = 5
+Kconfig:45: Hello, my name is John.
+Kconfig:50: Hello, my name is .
+Kconfig:53: Hello, my name is John.