1 files changed, 94 insertions, 0 deletions
diff --git a/kernel/gen_kheaders.sh b/kernel/gen_kheaders.sh
new file mode 100755
index 0000000000..6d443ea22b
--- /dev/null
+++ b/kernel/gen_kheaders.sh
@@ -0,0 +1,94 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+# This script generates an archive consisting of kernel headers
+# for CONFIG_IKHEADERS.
+set -e
+sfile="$(readlink -f "$0")"
+outdir="$(pwd)"
+tarfile=$1
+cpio_dir=$outdir/${tarfile%/*}/.tmp_cpio_dir
+
+dir_list="
+include/
+arch/$SRCARCH/include/
+"
+
+type cpio > /dev/null
+
+# Support incremental builds by skipping archive generation
+# if timestamps of files being archived are not changed.
+
+# This block is useful for debugging the incremental builds.
+# Uncomment it for debugging.
+# if [ ! -f /tmp/iter ]; then iter=1; echo 1 > /tmp/iter;
+# else iter=$(($(cat /tmp/iter) + 1)); echo $iter > /tmp/iter; fi
+# find $all_dirs -name "*.h" | xargs ls -l > /tmp/ls-$iter
+
+all_dirs=
+if [ "$building_out_of_srctree" ]; then
+	for d in $dir_list; do
+		all_dirs="$all_dirs $srctree/$d"
+	done
+fi
+all_dirs="$all_dirs $dir_list"
+
+# include/generated/utsversion.h is ignored because it is generated after this
+# script is executed. (utsversion.h is unneeded for kheaders)
+#
+# When Kconfig regenerates include/generated/autoconf.h, its timestamp is
+# updated, but the contents might be still the same. When any CONFIG option is
+# changed, Kconfig touches the corresponding timestamp file include/config/*.
+# Hence, the md5sum detects the configuration change anyway. We do not need to
+# check include/generated/autoconf.h explicitly.
+#
+# Ignore them for md5 calculation to avoid pointless regeneration.
+headers_md5="$(find $all_dirs -name "*.h"			|
+		grep -v "include/generated/utsversion.h"	|
+		grep -v "include/generated/autoconf.h"	|
+		xargs ls -l | md5sum | cut -d ' ' -f1)"
+
+# Any changes to this script will also cause a rebuild of the archive.
+this_file_md5="$(ls -l $sfile | md5sum | cut -d ' ' -f1)"
+if [ -f $tarfile ]; then tarfile_md5="$(md5sum $tarfile | cut -d ' ' -f1)"; fi
+if [ -f kernel/kheaders.md5 ] &&
+	[ "$(head -n 1 kernel/kheaders.md5)" = "$headers_md5" ] &&
+	[ "$(head -n 2 kernel/kheaders.md5 | tail -n 1)" = "$this_file_md5" ] &&
+	[ "$(tail -n 1 kernel/kheaders.md5)" = "$tarfile_md5" ]; then
+		exit
+fi
+
+echo "  GEN     $tarfile"
+
+rm -rf $cpio_dir
+mkdir $cpio_dir
+
+if [ "$building_out_of_srctree" ]; then
+	(
+		cd $srctree
+		for f in $dir_list
+			do find "$f" -name "*.h";
+		done | cpio --quiet -pd $cpio_dir
+	)
+fi
+
+# The second CPIO can complain if files already exist which can happen with out
+# of tree builds having stale headers in srctree. Just silence CPIO for now.
+for f in $dir_list;
+	do find "$f" -name "*.h";
+done | cpio --quiet -pdu $cpio_dir >/dev/null 2>&1
+
+# Remove comments except SDPX lines
+find $cpio_dir -type f -print0 |
+	xargs -0 -P8 -n1 perl -pi -e 'BEGIN {undef $/;}; s/\/\*((?!SPDX).)*?\*\///smg;'
+
+# Create archive and try to normalize metadata for reproducibility.
+tar "${KBUILD_BUILD_TIMESTAMP:+--mtime=$KBUILD_BUILD_TIMESTAMP}" \
+    --owner=0 --group=0 --sort=name --numeric-owner \
+    -I $XZ -cf $tarfile -C $cpio_dir/ . > /dev/null
+
+echo $headers_md5 > kernel/kheaders.md5
+echo "$this_file_md5" >> kernel/kheaders.md5
+echo "$(md5sum $tarfile | cut -d ' ' -f1)" >> kernel/kheaders.md5
+
+rm -rf $cpio_dir