1#!/bin/sh
2
3# XIP kernel .data segment compressor
4#
5# Created by:	Nicolas Pitre, August 2017
6# Copyright:	(C) 2017  Linaro Limited
7#
8# This program is free software; you can redistribute it and/or modify
9# it under the terms of the GNU General Public License version 2 as
10# published by the Free Software Foundation.
11
12# This script locates the start of the .data section in xipImage and
13# substitutes it with a compressed version. The needed offsets are obtained
14# from symbol addresses in vmlinux. It is expected that .data extends to
15# the end of xipImage.
16
17set -e
18
19VMLINUX="$1"
20XIPIMAGE="$2"
21
22DD="dd status=none"
23
24# Use "make V=1" to debug this script.
25case "$KBUILD_VERBOSE" in
26*1*)
27	set -x
28	;;
29esac
30
31sym_val() {
32	# extract hex value for symbol in $1
33	local val=$($NM "$VMLINUX" | sed -n "/ $1$/{s/ .*$//p;q}")
34	[ "$val" ] || { echo "can't find $1 in $VMLINUX" 1>&2; exit 1; }
35	# convert from hex to decimal
36	echo $((0x$val))
37}
38
39__data_loc=$(sym_val __data_loc)
40_edata_loc=$(sym_val _edata_loc)
41base_offset=$(sym_val _xiprom)
42
43# convert to file based offsets
44data_start=$(($__data_loc - $base_offset))
45data_end=$(($_edata_loc - $base_offset))
46
47# Make sure data occupies the last part of the file.
48file_end=$(stat -c "%s" "$XIPIMAGE")
49if [ "$file_end" != "$data_end" ]; then
50	printf "end of xipImage doesn't match with _edata_loc (%#x vs %#x)\n" \
51	       $(($file_end + $base_offset)) $_edata_loc 2>&1
52	exit 1;
53fi
54
55# be ready to clean up
56trap 'rm -f "$XIPIMAGE.tmp"' 0 1 2 3
57
58# substitute the data section by a compressed version
59$DD if="$XIPIMAGE" count=$data_start iflag=count_bytes of="$XIPIMAGE.tmp"
60$DD if="$XIPIMAGE"  skip=$data_start iflag=skip_bytes |
61gzip -9 >> "$XIPIMAGE.tmp"
62
63# replace kernel binary
64mv -f "$XIPIMAGE.tmp" "$XIPIMAGE"
65