kbuild: do not do section mismatch checks on vmlinux in 2nd pass

We already check and warn about section mismatches from vmlinux
(build as vmlinux.o) during first pass so skip the checks
during the 2nd pass where we process modules.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

scripts/Makefile.modpost

@@ -56,23 +56,24 @@ _modpost: $(if $(KBUILD_MODPOST_NOFINAL), $(modules:.ko:.o),$(modules))
 
 # Step 2), invoke modpost
 #  Includes step 3,4
+modpost = scripts/mod/modpost                    \
+ $(if $(CONFIG_MODVERSIONS),-m)                  \
+ $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a,)       \
+ $(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile)   \
+ $(if $(KBUILD_EXTMOD),-I $(modulesymfile))      \
+ $(if $(KBUILD_EXTMOD),-o $(modulesymfile))      \
+ $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w)
+
 quiet_cmd_modpost = MODPOST $(words $(filter-out vmlinux FORCE, $^)) modules
-      cmd_modpost = scripts/mod/modpost            \
-        $(if $(CONFIG_MODVERSIONS),-m)             \
-	$(if $(CONFIG_MODULE_SRCVERSION_ALL),-a,)  \
-	$(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile) \
-	$(if $(KBUILD_EXTMOD),-I $(modulesymfile)) \
-	$(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \
-	$(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w)
+      cmd_modpost = $(modpost) -s
 
 PHONY += __modpost
 __modpost: $(modules:.ko=.o) FORCE
 	$(call cmd,modpost) $(wildcard vmlinux) $(filter-out FORCE,$^)
 
 quiet_cmd_kernel-mod = MODPOST $@
-      cmd_kernel-mod = $(cmd_modpost) $@
+      cmd_kernel-mod = $(modpost) $@
 
-PHONY += vmlinux
 vmlinux.o: FORCE
 	$(call cmd,kernel-mod)
 

scripts/mod/modpost.c

@@ -23,6 +23,8 @@ int have_vmlinux = 0;
 static int all_versions = 0;
 /* If we are modposting external module set to 1 */
 static int external_module = 0;
+/* Warn about section mismatch in vmlinux if set to 1 */
+static int vmlinux_section_warnings = 1;
 /* Only warn about unresolved symbols */
 static int warn_unresolved = 0;
 /* How a symbol is exported */
@@ -1257,8 +1259,10 @@ static void read_symbols(char *modname)
 		handle_modversions(mod, &info, sym, symname);
 		handle_moddevtable(mod, &info, sym, symname);
 	}
-	check_sec_ref(mod, modname, &info, init_section, init_section_ref_ok);
-	check_sec_ref(mod, modname, &info, exit_section, exit_section_ref_ok);
+	if (is_vmlinux(modname) && vmlinux_section_warnings) {
+		check_sec_ref(mod, modname, &info, init_section, init_section_ref_ok);
+		check_sec_ref(mod, modname, &info, exit_section, exit_section_ref_ok);
+	}
 
 	version = get_modinfo(info.modinfo, info.modinfo_len, "version");
 	if (version)
@@ -1626,7 +1630,7 @@ int main(int argc, char **argv)
 	int opt;
 	int err;
 
-	while ((opt = getopt(argc, argv, "i:I:mo:aw")) != -1) {
+	while ((opt = getopt(argc, argv, "i:I:mso:aw")) != -1) {
 		switch(opt) {
 			case 'i':
 				kernel_read = optarg;
@@ -1644,6 +1648,9 @@ int main(int argc, char **argv)
 			case 'a':
 				all_versions = 1;
 				break;
+			case 's':
+				vmlinux_section_warnings = 0;
+				break;
 			case 'w':
 				warn_unresolved = 1;
 				break;