Merge tag 'kbuild-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:
 "Build system:

   - add CONFIG_UNUSED_KSYMS_WHITELIST, which will be useful to define a
     fixed set of export symbols for Generic Kernel Image (GKI)

   - allow to run 'make dt_binding_check' without .config

   - use full schema for checking DT examples in *.yaml files

   - make modpost fail for missing MODULE_IMPORT_NS(), which makes more
     sense because we know the produced modules are never loadable

   - Remove unused 'AS' variable

  Kconfig:

   - sanitize DEFCONFIG_LIST, and remove ARCH_DEFCONFIG from Kconfig
     files

   - relax the 'imply' behavior so that symbols implied by 'y' can
     become 'm'

   - make 'imply' obey 'depends on' in order to make 'imply' really weak

  Misc:

   - add documentation on building the kernel with Clang/LLVM

   - revive __HAVE_ARCH_STRLEN for 32bit sparc to use optimized strlen()

   - fix warning from deb-pkg builds when CONFIG_DEBUG_INFO=n

   - various script and Makefile cleanups"

* tag 'kbuild-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (34 commits)
  Makefile: Update kselftest help information
  kbuild: deb-pkg: fix warning when CONFIG_DEBUG_INFO is unset
  kbuild: add outputmakefile to no-dot-config-targets
  kbuild: remove AS variable
  net: wan: wanxl: refactor the firmware rebuild rule
  net: wan: wanxl: use $(M68KCC) instead of $(M68KAS) for rebuilding firmware
  net: wan: wanxl: use allow to pass CROSS_COMPILE_M68k for rebuilding firmware
  kbuild: add comment about grouped target
  kbuild: add -Wall to KBUILD_HOSTCXXFLAGS
  kconfig: remove unused variable in qconf.cc
  sparc: revive __HAVE_ARCH_STRLEN for 32bit sparc
  kbuild: refactor Makefile.dtbinst more
  kbuild: compute the dtbs_install destination more simply
  Makefile: disallow data races on gcc-10 as well
  kconfig: make 'imply' obey the direct dependency
  kconfig: allow symbols implied by y to become m
  net: drop_monitor: use IS_REACHABLE() to guard net_dm_hw_report()
  modpost: return error if module is missing ns imports and MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS=n
  modpost: rework and consolidate logging interface
  kbuild: allow to run dt_binding_check without kernel configuration
  ...

2 files changed, 51 insertions, 46 deletions

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index acf0a69d68ce..5c3c50c5ec52 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -39,6 +39,8 @@ static int sec_mismatch_count = 0;
 static int sec_mismatch_fatal = 0;
 /* ignore missing files */
 static int ignore_missing_files;
+/* If set to 1, only warn (instead of error) about missing ns imports */
+static int allow_missing_ns_imports;
 
 enum export {
 	export_plain,      export_unused,     export_gpl,
@@ -51,41 +53,33 @@ enum export {
 
 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
 
-#define PRINTF __attribute__ ((format (printf, 1, 2)))
-
-PRINTF void fatal(const char *fmt, ...)
+void __attribute__((format(printf, 2, 3)))
+modpost_log(enum loglevel loglevel, const char *fmt, ...)
 {
 	va_list arglist;
 
-	fprintf(stderr, "FATAL: ");
-
-	va_start(arglist, fmt);
-	vfprintf(stderr, fmt, arglist);
-	va_end(arglist);
-
-	exit(1);
-}
-
-PRINTF void warn(const char *fmt, ...)
-{
-	va_list arglist;
+	switch (loglevel) {
+	case LOG_WARN:
+		fprintf(stderr, "WARNING: ");
+		break;
+	case LOG_ERROR:
+		fprintf(stderr, "ERROR: ");
+		break;
+	case LOG_FATAL:
+		fprintf(stderr, "FATAL: ");
+		break;
+	default: /* invalid loglevel, ignore */
+		break;
+	}
 
-	fprintf(stderr, "WARNING: ");
+	fprintf(stderr, "modpost: ");
 
 	va_start(arglist, fmt);
 	vfprintf(stderr, fmt, arglist);
 	va_end(arglist);
-}
-
-PRINTF void merror(const char *fmt, ...)
-{
-	va_list arglist;
 
-	fprintf(stderr, "ERROR: ");
-
-	va_start(arglist, fmt);
-	vfprintf(stderr, fmt, arglist);
-	va_end(arglist);
+	if (loglevel == LOG_FATAL)
+		exit(1);
 }
 
 static inline bool strends(const char *str, const char *postfix)
@@ -113,7 +107,7 @@ static int is_vmlinux(const char *modname)
 void *do_nofail(void *ptr, const char *expr)
 {
 	if (!ptr)
-		fatal("modpost: Memory allocation failure: %s.\n", expr);
+		fatal("Memory allocation failure: %s.\n", expr);
 
 	return ptr;
 }
@@ -2022,7 +2016,7 @@ static void read_symbols(const char *modname)
 
 	license = get_modinfo(&info, "license");
 	if (!license && !is_vmlinux(modname))
-		warn("modpost: missing MODULE_LICENSE() in %s\n"
+		warn("missing MODULE_LICENSE() in %s\n"
 		     "see include/linux/module.h for "
 		     "more information\n", modname);
 	while (license) {
@@ -2153,15 +2147,15 @@ static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
 
 	switch (exp) {
 	case export_gpl:
-		fatal("modpost: GPL-incompatible module %s%s "
+		fatal("GPL-incompatible module %s%s "
 		      "uses GPL-only symbol '%s'\n", m, e, s);
 		break;
 	case export_unused_gpl:
-		fatal("modpost: GPL-incompatible module %s%s "
+		fatal("GPL-incompatible module %s%s "
 		      "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
 		break;
 	case export_gpl_future:
-		warn("modpost: GPL-incompatible module %s%s "
+		warn("GPL-incompatible module %s%s "
 		      "uses future GPL-only symbol '%s'\n", m, e, s);
 		break;
 	case export_plain:
@@ -2179,7 +2173,7 @@ static void check_for_unused(enum export exp, const char *m, const char *s)
 	switch (exp) {
 	case export_unused:
 	case export_unused_gpl:
-		warn("modpost: module %s%s "
+		warn("module %s%s "
 		      "uses symbol '%s' marked UNUSED\n", m, e, s);
 		break;
 	default:
@@ -2198,14 +2192,11 @@ static int check_exports(struct module *mod)
 		exp = find_symbol(s->name);
 		if (!exp || exp->module == mod) {
 			if (have_vmlinux && !s->weak) {
-				if (warn_unresolved) {
-					warn("\"%s\" [%s.ko] undefined!\n",
-					     s->name, mod->name);
-				} else {
-					merror("\"%s\" [%s.ko] undefined!\n",
-					       s->name, mod->name);
+				modpost_log(warn_unresolved ? LOG_WARN : LOG_ERROR,
+					    "\"%s\" [%s.ko] undefined!\n",
+					    s->name, mod->name);
+				if (!warn_unresolved)
 					err = 1;
-				}
 			}
 			continue;
 		}
@@ -2217,8 +2208,11 @@ static int check_exports(struct module *mod)
 
 		if (exp->namespace &&
 		    !module_imports_namespace(mod, exp->namespace)) {
-			warn("module %s uses symbol %s from namespace %s, but does not import it.\n",
-			     basename, exp->name, exp->namespace);
+			modpost_log(allow_missing_ns_imports ? LOG_WARN : LOG_ERROR,
+				    "module %s uses symbol %s from namespace %s, but does not import it.\n",
+				    basename, exp->name, exp->namespace);
+			if (!allow_missing_ns_imports)
+				err = 1;
 			add_namespace(&mod->missing_namespaces, exp->namespace);
 		}
 
@@ -2565,7 +2559,7 @@ int main(int argc, char **argv)
 	struct ext_sym_list *extsym_iter;
 	struct ext_sym_list *extsym_start = NULL;
 
-	while ((opt = getopt(argc, argv, "i:e:mnsT:o:awEd:")) != -1) {
+	while ((opt = getopt(argc, argv, "i:e:mnsT:o:awENd:")) != -1) {
 		switch (opt) {
 		case 'i':
 			kernel_read = optarg;
@@ -2603,6 +2597,9 @@ int main(int argc, char **argv)
 		case 'E':
 			sec_mismatch_fatal = 1;
 			break;
+		case 'N':
+			allow_missing_ns_imports = 1;
+			break;
 		case 'd':
 			missing_namespace_deps = optarg;
 			break;
@@ -2658,7 +2655,7 @@ int main(int argc, char **argv)
 	if (dump_write)
 		write_dump(dump_write);
 	if (sec_mismatch_count && sec_mismatch_fatal)
-		fatal("modpost: Section mismatches detected.\n"
+		fatal("Section mismatches detected.\n"
 		      "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
 	for (n = 0; n < SYMBOL_HASH_SIZE; n++) {
 		struct symbol *s;
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index 64a82d2d85f6..60dca9b7106b 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -198,6 +198,14 @@ void *grab_file(const char *filename, unsigned long *size);
 char* get_next_line(unsigned long *pos, void *file, unsigned long size);
 void release_file(void *file, unsigned long size);
 
-void fatal(const char *fmt, ...);
-void warn(const char *fmt, ...);
-void merror(const char *fmt, ...);
+enum loglevel {
+	LOG_WARN,
+	LOG_ERROR,
+	LOG_FATAL
+};
+
+void modpost_log(enum loglevel loglevel, const char *fmt, ...);
+
+#define warn(fmt, args...)	modpost_log(LOG_WARN, fmt, ##args)
+#define merror(fmt, args...)	modpost_log(LOG_ERROR, fmt, ##args)
+#define fatal(fmt, args...)	modpost_log(LOG_FATAL, fmt, ##args)