kconfig: add warn-unknown-symbols sanity check

[ Upstream commit 7cd343008b967423b06af8f6d3236749c67d12e8 ]

Introduce KCONFIG_WARN_UNKNOWN_SYMBOLS environment variable,
which makes Kconfig warn about unknown config symbols.

This is especially useful for continuous kernel uprevs when
some symbols can be either removed or renamed between kernel
releases (which can go unnoticed otherwise).

By default KCONFIG_WARN_UNKNOWN_SYMBOLS generates warnings,
which are non-terminal. There is an additional environment
variable KCONFIG_WERROR that overrides this behaviour and
turns warnings into errors.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Stable-dep-of: a409fc1463d6 ("kconfig: fix memory leak in sym_warn_unmet_dep()")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/Documentation/kbuild/kconfig.rst b/Documentation/kbuild/kconfig.rst
index 5967c79c3baa76d0a9bd955ffed4840e3f022fa1..eee0d298774abf820b60a5f0119330d2eb1d1be2 100644 (file)
--- a/Documentation/kbuild/kconfig.rst
+++ b/Documentation/kbuild/kconfig.rst
@@ -54,6 +54,15 @@ KCONFIG_OVERWRITECONFIG
 If you set KCONFIG_OVERWRITECONFIG in the environment, Kconfig will not
 break symlinks when .config is a symlink to somewhere else.
 
+KCONFIG_WARN_UNKNOWN_SYMBOLS
+----------------------------
+This environment variable makes Kconfig warn about all unrecognized
+symbols in the config input.
+
+KCONFIG_WERROR
+--------------
+If set, Kconfig treats warnings as errors.
+
 `CONFIG_`
 ---------
 If you set `CONFIG_` in the environment, Kconfig will prefix all symbols

diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index 469450b0a5176f2d2a6ef4b8627d9fa98c8fc644..033f2882436d3efc9cd8847e88c5039c8bbc95cd 100644 (file)
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -351,7 +351,11 @@ int conf_read_simple(const char *name, int def)
        char *p, *p2;
        struct symbol *sym;
        int i, def_flags;
+       const char *warn_unknown;
+       const char *werror;
 
+       warn_unknown = getenv("KCONFIG_WARN_UNKNOWN_SYMBOLS");
+       werror = getenv("KCONFIG_WERROR");
        if (name) {
                in = zconf_fopen(name);
        } else {
@@ -441,6 +445,10 @@ load:
                        if (def == S_DEF_USER) {
                                sym = sym_find(line + 2 + strlen(CONFIG_));
                                if (!sym) {
+                                       if (warn_unknown)
+                                               conf_warning("unknown symbol: %s",
+                                                            line + 2 + strlen(CONFIG_));
+
                                        conf_set_changed(true);
                                        continue;
                                }
@@ -475,7 +483,7 @@ load:
 
                        sym = sym_find(line + strlen(CONFIG_));
                        if (!sym) {
-                               if (def == S_DEF_AUTO)
+                               if (def == S_DEF_AUTO) {
                                        /*
                                         * Reading from include/config/auto.conf
                                         * If CONFIG_FOO previously existed in
@@ -483,8 +491,13 @@ load:
                                         * include/config/FOO must be touched.
                                         */
                                        conf_touch_dep(line + strlen(CONFIG_));
-                               else
+                               } else {
+                                       if (warn_unknown)
+                                               conf_warning("unknown symbol: %s",
+                                                            line + strlen(CONFIG_));
+
                                        conf_set_changed(true);
+                               }
                                continue;
                        }
 
@@ -523,6 +536,10 @@ load:
        }
        free(line);
        fclose(in);
+
+       if (conf_warnings && werror)
+               exit(1);
+
        return 0;
 }