linux/arch/arm/boot/deflate_xip_data.sh
Denis Efremov 8dfb61dcba kbuild: add variables for compression tools
Allow user to use alternative implementations of compression tools,
such as pigz, pbzip2, pxz. For example, multi-threaded tools to
speed up the build:
$ make GZIP=pigz BZIP2=pbzip2

Variables _GZIP, _BZIP2, _LZOP are used internally because original env
vars are reserved by the tools. The use of GZIP in gzip tool is obsolete
since 2015. However, alternative implementations (e.g., pigz) still rely
on it. BZIP2, BZIP, LZOP vars are not obsolescent.

The credit goes to @grsecurity.

As a sidenote, for multi-threaded lzma, xz compression one can use:
$ export XZ_OPT="--threads=0"

Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06 23:42:01 +09:00

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#!/bin/sh
# SPDX-License-Identifier: GPL-2.0-only
# XIP kernel .data segment compressor
#
# Created by: Nicolas Pitre, August 2017
# Copyright: (C) 2017 Linaro Limited
#
# This script locates the start of the .data section in xipImage and
# substitutes it with a compressed version. The needed offsets are obtained
# from symbol addresses in vmlinux. It is expected that .data extends to
# the end of xipImage.
set -e
VMLINUX="$1"
XIPIMAGE="$2"
DD="dd status=none"
# Use "make V=1" to debug this script.
case "$KBUILD_VERBOSE" in
*1*)
set -x
;;
esac
sym_val() {
# extract hex value for symbol in $1
local val=$($NM "$VMLINUX" 2>/dev/null | sed -n "/ $1\$/{s/ .*$//p;q}")
[ "$val" ] || { echo "can't find $1 in $VMLINUX" 1>&2; exit 1; }
# convert from hex to decimal
echo $((0x$val))
}
__data_loc=$(sym_val __data_loc)
_edata_loc=$(sym_val _edata_loc)
base_offset=$(sym_val _xiprom)
# convert to file based offsets
data_start=$(($__data_loc - $base_offset))
data_end=$(($_edata_loc - $base_offset))
# Make sure data occupies the last part of the file.
file_end=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" "$XIPIMAGE")
if [ "$file_end" != "$data_end" ]; then
printf "end of xipImage doesn't match with _edata_loc (%#x vs %#x)\n" \
$(($file_end + $base_offset)) $_edata_loc 1>&2
exit 1;
fi
# be ready to clean up
trap 'rm -f "$XIPIMAGE.tmp"; exit 1' 1 2 3
# substitute the data section by a compressed version
$DD if="$XIPIMAGE" count=$data_start iflag=count_bytes of="$XIPIMAGE.tmp"
$DD if="$XIPIMAGE" skip=$data_start iflag=skip_bytes |
$_GZIP -9 >> "$XIPIMAGE.tmp"
# replace kernel binary
mv -f "$XIPIMAGE.tmp" "$XIPIMAGE"