kbuild: split the second line of *.mod into *.usyms

The *.mod files have two lines; the first line lists the member objects
of the module, and the second line, if CONFIG_TRIM_UNUSED_KSYMS=y, lists
the undefined symbols.

Currently, we generate *.mod after constructing composite modules,
otherwise, we cannot compute the second line. No prerequisite is
required to print the first line.

They are orthogonal. Splitting them into separate commands will ease
further cleanups.

This commit splits the list of undefined symbols out to *.usyms files.

Previously, the list of undefined symbols ended up with a very long
line, but now it has one symbol per line.

Use sed like we did before commit 7d32358be8ac ("kbuild: avoid split
lines in .mod files").

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

6 files changed, 25 insertions, 26 deletions

diff --git a/.gitignore b/.gitignore
index 7afd412dadd2..265959544978 100644
--- a/.gitignore
+++ b/.gitignore
@@ -45,6 +45,7 @@
 *.symversions
 *.tab.[ch]
 *.tar
+*.usyms
 *.xz
 *.zst
 Module.symvers
diff --git a/Makefile b/Makefile
index d9336e783be3..82ee893909e9 100644
--- a/Makefile
+++ b/Makefile
@@ -1848,7 +1848,7 @@ clean: $(clean-dirs)
 		-o -name '*.ko.*' \
 		-o -name '*.dtb' -o -name '*.dtbo' -o -name '*.dtb.S' -o -name '*.dt.yaml' \
 		-o -name '*.dwo' -o -name '*.lst' \
-		-o -name '*.su' -o -name '*.mod' \
+		-o -name '*.su' -o -name '*.mod' -o -name '*.usyms' \
 		-o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
 		-o -name '*.lex.c' -o -name '*.tab.[ch]' \
 		-o -name '*.asn1.[ch]' \
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 857329844789..6ae92d119dfa 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -85,7 +85,8 @@ ifdef need-builtin
 targets-for-builtin += $(obj)/built-in.a
 endif
 
-targets-for-modules := $(patsubst %.o, %.mod, $(filter %.o, $(obj-m)))
+targets-for-modules := $(foreach x, mod $(if $(CONFIG_TRIM_UNUSED_KSYMS), usyms), \
+				$(patsubst %.o, %.$x, $(filter %.o, $(obj-m))))
 
 ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),)
 targets-for-modules += $(patsubst %.o, %.prelink.o, $(filter %.o, $(obj-m)))
@@ -256,9 +257,6 @@ endif
 ifdef CONFIG_TRIM_UNUSED_KSYMS
 cmd_gen_ksymdeps = \
 	$(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd
-
-# List module undefined symbols
-undefined_syms = $(NM) $< | $(AWK) '$$1 == "U" { printf("%s%s", x++ ? " " : "", $$2) }';
 endif
 
 define rule_cc_o_c
@@ -305,14 +303,17 @@ $(obj)/%.prelink.o: $(obj)/%.o FORCE
 	$(call if_changed,cc_prelink_modules)
 endif
 
-cmd_mod = { \
-	echo $(addprefix $(obj)/, $(call real-search, $*.o, .o, -objs -y -m)); \
-	$(undefined_syms) echo; \
-	} > $@
+cmd_mod = echo $(addprefix $(obj)/, $(call real-search, $*.o, .o, -objs -y -m)) > $@
 
 $(obj)/%.mod: $(obj)/%$(mod-prelink-ext).o FORCE
 	$(call if_changed,mod)
 
+# List module undefined symbols
+cmd_undefined_syms = $(NM) $< | sed -n 's/^  *U //p' > $@
+
+$(obj)/%.usyms: $(obj)/%$(mod-prelink-ext).o FORCE
+	$(call if_changed,undefined_syms)
+
 quiet_cmd_cc_lst_c = MKLST   $@
       cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
 		     $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
diff --git a/scripts/adjust_autoksyms.sh b/scripts/adjust_autoksyms.sh
index 59fdb875e818..f1b5ac818411 100755
--- a/scripts/adjust_autoksyms.sh
+++ b/scripts/adjust_autoksyms.sh
@@ -35,7 +35,7 @@ case "$KBUILD_VERBOSE" in
 esac
 
 # Generate a new symbol list file
-$CONFIG_SHELL $srctree/scripts/gen_autoksyms.sh "$new_ksyms_file"
+$CONFIG_SHELL $srctree/scripts/gen_autoksyms.sh --modorder "$new_ksyms_file"
 
 # Extract changes between old and new list and touch corresponding
 # dependency files.
diff --git a/scripts/gen_autoksyms.sh b/scripts/gen_autoksyms.sh
index 120225c541c5..faacf7062122 100755
--- a/scripts/gen_autoksyms.sh
+++ b/scripts/gen_autoksyms.sh
@@ -2,13 +2,10 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
 # Create an autoksyms.h header file from the list of all module's needed symbols
-# as recorded on the second line of *.mod files and the user-provided symbol
-# whitelist.
+# as recorded in *.usyms files and the user-provided symbol whitelist.
 
 set -e
 
-output_file="$1"
-
 # Use "make V=1" to debug this script.
 case "$KBUILD_VERBOSE" in
 *1*)
@@ -16,6 +13,15 @@ case "$KBUILD_VERBOSE" in
 	;;
 esac
 
+read_modorder=
+
+if [ "$1" = --modorder ]; then
+	shift
+	read_modorder=1
+fi
+
+output_file="$1"
+
 needed_symbols=
 
 # Special case for modversions (see modpost.c)
@@ -41,10 +47,8 @@ cat > "$output_file" << EOT
 
 EOT
 
-[ -f modules.order ] && modlist=modules.order || modlist=/dev/null
-
 {
-	sed 's/ko$/mod/' $modlist | xargs -n1 sed -n -e '2p'
+	[ -n "${read_modorder}" ] && sed 's/ko$/usyms/' modules.order | xargs cat
 	echo "$needed_symbols"
 	[ -n "$ksym_wl" ] && cat "$ksym_wl"
 } | sed -e 's/ /\n/g' | sed -n -e '/^$/!p' |
diff --git a/scripts/mod/sumversion.c b/scripts/mod/sumversion.c
index 905c0ec291e1..0125698f2037 100644
--- a/scripts/mod/sumversion.c
+++ b/scripts/mod/sumversion.c
@@ -387,7 +387,7 @@ out_file:
 /* Calc and record src checksum. */
 void get_src_version(const char *modname, char sum[], unsigned sumlen)
 {
-	char *buf, *pos, *firstline;
+	char *buf;
 	struct md4_ctx md;
 	char *fname;
 	char filelist[PATH_MAX + 1];
@@ -397,15 +397,8 @@ void get_src_version(const char *modname, char sum[], unsigned sumlen)
 
 	buf = read_text_file(filelist);
 
-	pos = buf;
-	firstline = get_line(&pos);
-	if (!firstline) {
-		warn("bad ending versions file for %s\n", modname);
-		goto free;
-	}
-
 	md4_init(&md);
-	while ((fname = strsep(&firstline, " "))) {
+	while ((fname = strsep(&buf, " \n"))) {
 		if (!*fname)
 			continue;
 		if (!(is_static_library(fname)) &&