find $cpio_dir -type f -print0 |
xargs -0 -P8 -n1 perl -pi -e 'BEGIN {undef $/;}; s/\/\*((?!SPDX).)*?\*\///smg;'
-tar -Jcf $tarfile -C $cpio_dir/ . > /dev/null
+# Create archive and try to normalize metadata for reproducibility
+tar "${KBUILD_BUILD_TIMESTAMP:+--mtime=$KBUILD_BUILD_TIMESTAMP}" \
+ --owner=0 --group=0 --sort=name --numeric-owner \
+ -Jcf $tarfile -C $cpio_dir/ . > /dev/null
echo "$src_files_md5" > kernel/kheaders.md5
echo "$obj_files_md5" >> kernel/kheaders.md5