Merge tag 'kbuild-fixes-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - Fix UNUSED_KSYMS_WHITELIST for Clang LTO

 - Make -s builds really silent irrespective of V= option

 - Fix build error when SUBLEVEL or PATCHLEVEL is empty

* tag 'kbuild-fixes-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: Fix <linux/version.h> for empty SUBLEVEL or PATCHLEVEL again
  kbuild: make -s option take precedence over V=1
  ia64: remove redundant READELF from arch/ia64/Makefile
  kbuild: do not include include/config/auto.conf from adjust_autoksyms.sh
  kbuild: fix UNUSED_KSYMS_WHITELIST for Clang LTO
  kbuild: lto: add _mcount to list of used symbols

3 files changed, 26 insertions, 17 deletions

diff --git a/scripts/adjust_autoksyms.sh b/scripts/adjust_autoksyms.sh
index 2b366d945ccb..d8f6f9c63043 100755
--- a/scripts/adjust_autoksyms.sh
+++ b/scripts/adjust_autoksyms.sh
@@ -34,9 +34,6 @@ case "$KBUILD_VERBOSE" in
 	;;
 esac
 
-# We need access to CONFIG_ symbols
-. include/config/auto.conf
-
 # Generate a new symbol list file
 $CONFIG_SHELL $srctree/scripts/gen_autoksyms.sh "$new_ksyms_file"
 
diff --git a/scripts/gen_autoksyms.sh b/scripts/gen_autoksyms.sh
index d54dfba15bf2..da320151e7c3 100755
--- a/scripts/gen_autoksyms.sh
+++ b/scripts/gen_autoksyms.sh
@@ -19,7 +19,26 @@ esac
 # We need access to CONFIG_ symbols
 . include/config/auto.conf
 
-ksym_wl=/dev/null
+needed_symbols=
+
+# Special case for modversions (see modpost.c)
+if [ -n "$CONFIG_MODVERSIONS" ]; then
+	needed_symbols="$needed_symbols module_layout"
+fi
+
+# With CONFIG_LTO_CLANG, LLVM bitcode has not yet been compiled into a binary
+# when the .mod files are generated, which means they don't yet contain
+# references to certain symbols that will be present in the final binaries.
+if [ -n "$CONFIG_LTO_CLANG" ]; then
+	# intrinsic functions
+	needed_symbols="$needed_symbols memcpy memmove memset"
+	# ftrace
+	needed_symbols="$needed_symbols _mcount"
+	# stack protector symbols
+	needed_symbols="$needed_symbols __stack_chk_fail __stack_chk_guard"
+fi
+
+ksym_wl=
 if [ -n "$CONFIG_UNUSED_KSYMS_WHITELIST" ]; then
 	# Use 'eval' to expand the whitelist path and check if it is relative
 	eval ksym_wl="$CONFIG_UNUSED_KSYMS_WHITELIST"
@@ -40,16 +59,14 @@ cat > "$output_file" << EOT
 EOT
 
 [ -f modules.order ] && modlist=modules.order || modlist=/dev/null
-sed 's/ko$/mod/' $modlist |
-xargs -n1 sed -n -e '2{s/ /\n/g;/^$/!p;}' -- |
-cat - "$ksym_wl" |
+
+{
+	sed 's/ko$/mod/' $modlist | xargs -n1 sed -n -e '2p'
+	echo "$needed_symbols"
+	[ -n "$ksym_wl" ] && cat "$ksym_wl"
+} | sed -e 's/ /\n/g' | sed -n -e '/^$/!p' |
 # Remove the dot prefix for ppc64; symbol names with a dot (.) hold entry
 # point addresses.
 sed -e 's/^\.//' |
 sort -u |
 sed -e 's/\(.*\)/#define __KSYM_\1 1/' >> "$output_file"
-
-# Special case for modversions (see modpost.c)
-if [ -n "$CONFIG_MODVERSIONS" ]; then
-	echo "#define __KSYM_module_layout 1" >> "$output_file"
-fi
diff --git a/scripts/lto-used-symbollist.txt b/scripts/lto-used-symbollist.txt
deleted file mode 100644
index 38e7bb9ebaae..000000000000
--- a/scripts/lto-used-symbollist.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-memcpy
-memmove
-memset
-__stack_chk_fail
-__stack_chk_guard