modpost: Add flag -E for making section mismatches fatal

The section mismatch warning can be easy to miss during the kernel build
process. Allow it to be marked as fatal to be easily caught and prevent
bugs from slipping in.

Setting CONFIG_SECTION_MISMATCH_WARN_ONLY=y causes these warnings to be
non-fatal, since there are a number of section mismatches when using
allmodconfig on some architectures, and we do not want to break these
builds by default.

Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Change-Id: Ic346706e3297c9f0d790e3552aa94e5cff9897a6
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 17 insertions, 7 deletions

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index d583c98fde31..b2ae8afc1ab1 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -38,6 +38,7 @@ static int warn_unresolved = 0;
 /* How a symbol is exported */
 static int sec_mismatch_count = 0;
 static int sec_mismatch_verbose = 1;
+static int sec_mismatch_fatal = 0;
 /* ignore missing files */
 static int ignore_missing_files;
 
@@ -2385,7 +2386,7 @@ 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:I:e:mnsST:o:awM:K:")) != -1) {
+	while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) {
 		switch (opt) {
 		case 'i':
 			kernel_read = optarg;
@@ -2426,6 +2427,9 @@ int main(int argc, char **argv)
 		case 'w':
 			warn_unresolved = 1;
 			break;
+		case 'E':
+			sec_mismatch_fatal = 1;
+			break;
 		default:
 			exit(1);
 		}
@@ -2475,14 +2479,20 @@ int main(int argc, char **argv)
 		sprintf(fname, "%s.mod.c", mod->name);
 		write_if_changed(&buf, fname);
 	}
-
 	if (dump_write)
 		write_dump(dump_write);
-	if (sec_mismatch_count && !sec_mismatch_verbose)
-		warn("modpost: Found %d section mismatch(es).\n"
-		     "To see full details build your kernel with:\n"
-		     "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
-		     sec_mismatch_count);
+	if (sec_mismatch_count) {
+		if (!sec_mismatch_verbose) {
+			warn("modpost: Found %d section mismatch(es).\n"
+			     "To see full details build your kernel with:\n"
+			     "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
+			     sec_mismatch_count);
+		}
+		if (sec_mismatch_fatal) {
+			fatal("modpost: Section mismatches detected.\n"
+			      "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
+		}
+	}
 
 	return err;
 }