Merge tag 'kbuild-v6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Add support for the EXPORT_SYMBOL_GPL_FOR_MODULES() macro, which
   exports a symbol only to specified modules

 - Improve ABI handling in gendwarfksyms

 - Forcibly link lib-y objects to vmlinux even if CONFIG_MODULES=n

 - Add checkers for redundant or missing <linux/export.h> inclusion

 - Deprecate the extra-y syntax

 - Fix a genksyms bug when including enum constants from *.symref files

* tag 'kbuild-v6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (28 commits)
  genksyms: Fix enum consts from a reference affecting new values
  arch: use always-$(KBUILD_BUILTIN) for vmlinux.lds
  kbuild: set y instead of 1 to KBUILD_{BUILTIN,MODULES}
  efi/libstub: use 'targets' instead of extra-y in Makefile
  module: make __mod_device_table__* symbols static
  scripts/misc-check: check unnecessary #include <linux/export.h> when W=1
  scripts/misc-check: check missing #include <linux/export.h> when W=1
  scripts/misc-check: add double-quotes to satisfy shellcheck
  kbuild: move W=1 check for scripts/misc-check to top-level Makefile
  scripts/tags.sh: allow to use alternative ctags implementation
  kconfig: introduce menu type enum
  docs: symbol-namespaces: fix reST warning with literal block
  kbuild: link lib-y objects to vmlinux forcibly even when CONFIG_MODULES=n
  tinyconfig: enable CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
  docs/core-api/symbol-namespaces: drop table of contents and section numbering
  modpost: check forbidden MODULE_IMPORT_NS("module:") at compile time
  kbuild: move kbuild syntax processing to scripts/Makefile.build
  Makefile: remove dependency on archscripts for header installation
  Documentation/kbuild: Add new gendwarfksyms kABI rules
  Documentation/kbuild: Drop section numbers
  ...

1 files changed, 51 insertions, 5 deletions

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index be89921d60b6..5ca7c268294e 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -28,6 +28,8 @@
 #include "modpost.h"
 #include "../../include/linux/license.h"
 
+#define MODULE_NS_PREFIX "module:"
+
 static bool module_enabled;
 /* Are we using CONFIG_MODVERSIONS? */
 static bool modversions;
@@ -1595,11 +1597,14 @@ static void read_symbols(const char *modname)
 			license = get_next_modinfo(&info, "license", license);
 		}
 
-		namespace = get_modinfo(&info, "import_ns");
-		while (namespace) {
+		for (namespace = get_modinfo(&info, "import_ns");
+		     namespace;
+		     namespace = get_next_modinfo(&info, "import_ns", namespace)) {
+			if (strstarts(namespace, MODULE_NS_PREFIX))
+				error("%s: explicitly importing namespace \"%s\" is not allowed.\n",
+				      mod->name, namespace);
+
 			add_namespace(&mod->imported_namespaces, namespace);
-			namespace = get_next_modinfo(&info, "import_ns",
-						     namespace);
 		}
 
 		if (!get_modinfo(&info, "description"))
@@ -1684,6 +1689,46 @@ void buf_write(struct buffer *buf, const char *s, int len)
 	buf->pos += len;
 }
 
+/**
+ * verify_module_namespace() - does @modname have access to this symbol's @namespace
+ * @namespace: export symbol namespace
+ * @modname: module name
+ *
+ * If @namespace is prefixed with "module:" to indicate it is a module namespace
+ * then test if @modname matches any of the comma separated patterns.
+ *
+ * The patterns only support tail-glob.
+ */
+static bool verify_module_namespace(const char *namespace, const char *modname)
+{
+	size_t len, modlen = strlen(modname);
+	const char *prefix = "module:";
+	const char *sep;
+	bool glob;
+
+	if (!strstarts(namespace, prefix))
+		return false;
+
+	for (namespace += strlen(prefix); *namespace; namespace = sep) {
+		sep = strchrnul(namespace, ',');
+		len = sep - namespace;
+
+		glob = false;
+		if (sep[-1] == '*') {
+			len--;
+			glob = true;
+		}
+
+		if (*sep)
+			sep++;
+
+		if (strncmp(namespace, modname, len) == 0 && (glob || len == modlen))
+			return true;
+	}
+
+	return false;
+}
+
 static void check_exports(struct module *mod)
 {
 	struct symbol *s, *exp;
@@ -1711,7 +1756,8 @@ static void check_exports(struct module *mod)
 
 		basename = get_basename(mod->name);
 
-		if (!contains_namespace(&mod->imported_namespaces, exp->namespace)) {
+		if (!verify_module_namespace(exp->namespace, basename) &&
+		    !contains_namespace(&mod->imported_namespaces, exp->namespace)) {
 			modpost_log(!allow_missing_ns_imports,
 				    "module %s uses symbol %s from namespace %s, but does not import it.\n",
 				    basename, exp->name, exp->namespace);