kconfig: add defconfig_list/module option

This makes it possible to change two options which were hardcoded sofar.
1. Any symbol can now take the role of CONFIG_MODULES
2. The more useful option is to change the list of default file names,
   which kconfig uses to load the base configuration if .config isn't
   available.

Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

8 files changed, 61 insertions, 24 deletions

diff --git a/init/Kconfig b/init/Kconfig
index 3b36a1d53656..9fb403af1085 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1,3 +1,11 @@
+config DEFCONFIG_LIST
+        string
+        option defconfig_list
+        default "/lib/modules/$UNAME_RELEASE/.config"
+        default "/etc/kernel-config"
+        default "/boot/config-$UNAME_RELEASE"
+        default "arch/$ARCH/defconfig"
+
 menu "Code maturity level options"
 
 config EXPERIMENTAL
diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index e28cd0c2ca08..5bd66f451189 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -25,15 +25,6 @@ const char conf_def_filename[] = ".config";
 
 const char conf_defname[] = "arch/$ARCH/defconfig";
 
-const char *conf_confnames[] = {
-        ".config",
-        "/lib/modules/$UNAME_RELEASE/.config",
-        "/etc/kernel-config",
-        "/boot/config-$UNAME_RELEASE",
-        conf_defname,
-        NULL,
-};
-
 static void conf_warning(const char *fmt, ...)
 {
         va_list ap;
@@ -98,16 +89,21 @@ int conf_read_simple(const char *name, int def)
         if (name) {
                 in = zconf_fopen(name);
         } else {
-                const char **names = conf_confnames;
-                name = *names++;
-                if (!name)
-                        return 1;
+                struct property *prop;
+
+                name = conf_def_filename;
                 in = zconf_fopen(name);
                 if (in)
                         goto load;
                 sym_change_count++;
-                while ((name = *names++)) {
-                        name = conf_expand_value(name);
+                if (!sym_defconfig_list)
+                        return 1;
+
+                for_all_defaults(sym_defconfig_list, prop) {
+                        if (expr_calc_value(prop->visible.expr) == no ||
+                            prop->expr->type != E_SYMBOL)
+                                continue;
+                        name = conf_expand_value(prop->expr->left.sym->name);
                         in = zconf_fopen(name);
                         if (in) {
                                 printf(_("#\n"
diff --git a/scripts/kconfig/expr.h b/scripts/kconfig/expr.h
index ffd42c7007ee..6084525f604b 100644
--- a/scripts/kconfig/expr.h
+++ b/scripts/kconfig/expr.h
@@ -156,6 +156,7 @@ struct file *lookup_file(const char *name);
 
 extern struct symbol symbol_yes, symbol_no, symbol_mod;
 extern struct symbol *modules_sym;
+extern struct symbol *sym_defconfig_list;
 extern int cdebug;
 struct expr *expr_alloc_symbol(struct symbol *sym);
 struct expr *expr_alloc_one(enum expr_type type, struct expr *ce);
diff --git a/scripts/kconfig/lkc.h b/scripts/kconfig/lkc.h
index 8e89d342889e..2d3d4ed3c9f2 100644
--- a/scripts/kconfig/lkc.h
+++ b/scripts/kconfig/lkc.h
@@ -104,6 +104,7 @@ const char *str_get(struct gstr *gs);
 /* symbol.c */
 void sym_init(void);
 void sym_clear_all_valid(void);
+void sym_set_all_changed(void);
 void sym_set_changed(struct symbol *sym);
 struct symbol *sym_check_deps(struct symbol *sym);
 struct property *prop_alloc(enum prop_type type, struct symbol *sym);
diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c
index 151ef2168a2c..a8afce24fb1b 100644
--- a/scripts/kconfig/menu.c
+++ b/scripts/kconfig/menu.c
@@ -154,6 +154,20 @@ void menu_add_symbol(enum prop_type type, struct symbol *sym, struct expr *dep)
 
 void menu_add_option(int token, char *arg)
 {
+        struct property *prop;
+
+        switch (token) {
+        case T_OPT_MODULES:
+                prop = prop_alloc(P_DEFAULT, modules_sym);
+                prop->expr = expr_alloc_symbol(current_entry->sym);
+                break;
+        case T_OPT_DEFCONFIG_LIST:
+                if (!sym_defconfig_list)
+                        sym_defconfig_list = current_entry->sym;
+                else if (sym_defconfig_list != current_entry->sym)
+                        zconf_error("trying to redefine defconfig symbol");
+                break;
+        }
 }
 
 static int menu_range_valid_sym(struct symbol *sym, struct symbol *sym2)
diff --git a/scripts/kconfig/symbol.c b/scripts/kconfig/symbol.c
index 78a60ba39e54..ee225ced2ce4 100644
--- a/scripts/kconfig/symbol.c
+++ b/scripts/kconfig/symbol.c
@@ -31,6 +31,7 @@ struct symbol symbol_yes = {
 };
 
 int sym_change_count;
+struct symbol *sym_defconfig_list;
 struct symbol *modules_sym;
 tristate modules_val;
 
@@ -352,10 +353,13 @@ void sym_calc_value(struct symbol *sym)
                 sym->curr.val = sym_calc_choice(sym);
         sym_validate_range(sym);
 
-        if (memcmp(&oldval, &sym->curr, sizeof(oldval)))
+        if (memcmp(&oldval, &sym->curr, sizeof(oldval))) {
                 sym_set_changed(sym);
-        if (modules_sym == sym)
-                modules_val = modules_sym->curr.tri;
+                if (modules_sym == sym) {
+                        sym_set_all_changed();
+                        modules_val = modules_sym->curr.tri;
+                }
+        }
 
         if (sym_is_choice(sym)) {
                 int flags = sym->flags & (SYMBOL_CHANGED | SYMBOL_WRITE);
@@ -449,11 +453,8 @@ bool sym_set_tristate_value(struct symbol *sym, tristate val)
         }
 
         sym->def[S_DEF_USER].tri = val;
-        if (oldval != val) {
+        if (oldval != val)
                 sym_clear_all_valid();
-                if (sym == modules_sym)
-                        sym_set_all_changed();
-        }
 
         return true;
 }
diff --git a/scripts/kconfig/zconf.tab.c_shipped b/scripts/kconfig/zconf.tab.c_shipped
index 137426e507ec..2fb0a4fc61d0 100644
--- a/scripts/kconfig/zconf.tab.c_shipped
+++ b/scripts/kconfig/zconf.tab.c_shipped
@@ -2112,7 +2112,9 @@ void conf_parse(const char *name)
 
         sym_init();
         menu_init();
-        modules_sym = sym_lookup("MODULES", 0);
+        modules_sym = sym_lookup(NULL, 0);
+        modules_sym->type = S_BOOLEAN;
+        modules_sym->flags |= SYMBOL_AUTO;
         rootmenu.prompt = menu_add_prompt(P_MENU, "Linux Kernel Configuration", NULL);
 
 #if YYDEBUG
@@ -2122,6 +2124,12 @@ void conf_parse(const char *name)
         zconfparse();
         if (zconfnerrs)
                 exit(1);
+        if (!modules_sym->prop) {
+                struct property *prop;
+
+                prop = prop_alloc(P_DEFAULT, modules_sym);
+                prop->expr = expr_alloc_symbol(sym_lookup("MODULES", 0));
+        }
         menu_finalize(&rootmenu);
         for_all_symbols(i, sym) {
                 sym_check_deps(sym);
diff --git a/scripts/kconfig/zconf.y b/scripts/kconfig/zconf.y
index 9d08582f2aa6..ab44feb3c600 100644
--- a/scripts/kconfig/zconf.y
+++ b/scripts/kconfig/zconf.y
@@ -481,7 +481,9 @@ void conf_parse(const char *name)
 
         sym_init();
         menu_init();
-        modules_sym = sym_lookup("MODULES", 0);
+        modules_sym = sym_lookup(NULL, 0);
+        modules_sym->type = S_BOOLEAN;
+        modules_sym->flags |= SYMBOL_AUTO;
         rootmenu.prompt = menu_add_prompt(P_MENU, "Linux Kernel Configuration", NULL);
 
 #if YYDEBUG
@@ -491,6 +493,12 @@ void conf_parse(const char *name)
         zconfparse();
         if (zconfnerrs)
                 exit(1);
+        if (!modules_sym->prop) {
+                struct property *prop;
+
+                prop = prop_alloc(P_DEFAULT, modules_sym);
+                prop->expr = expr_alloc_symbol(sym_lookup("MODULES", 0));
+        }
         menu_finalize(&rootmenu);
         for_all_symbols(i, sym) {
                 sym_check_deps(sym);