HardenedBSD/sys/tools/amd64_vdso.sh

#!/bin/sh
# SPDX-License-Identifier: BSD-2-Clause-FreeBSD
#
# Copyright (c) 2021 The FreeBSD Foundation
# All rights reserved.
#
# This software was developed by Konstantin Belousov <kib@FreeBSD.org>
# under sponsorship from the FreeBSD Foundation.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.

set -e

${CC} -x assembler-with-cpp -DLOCORE -fPIC -nostdinc -c \
   -o sigtramp.pico -I. -I"${S}" -include opt_global.h \
   "${S}"/amd64/amd64/sigtramp.S

# We need to make vdso as compact as possible, for it to leave space
# for other things in the shared page.  For this, we pack everything
# into single loadable segment.
#
# -z rodynamic is undocumented lld-specific option, seemingly required
# for lld to avoid putting dynamic into dedicated writeable segment,
# despite ldscript placement.  It is ignored by ld.bfd but ldscript
# alone is enough there.
#
${LD} --shared -Bsymbolic -soname="elf-vdso.so.1" \
   -T "${S}"/conf/vdso_amd64.ldscript \
   --eh-frame-hdr --no-undefined -z rodynamic -z norelro -nmagic \
   --hash-style=sysv --fatal-warnings --strip-all \
   -o elf-vdso.so.1 sigtramp.pico

${CC} -x assembler-with-cpp -DLOCORE -fPIC -nostdinc -c \
   -o elf-vdso.so.o -I. -I"${S}" -include opt_global.h \
   -DVDSO_NAME=elf_vdso_so_1 -DVDSO_FILE=elf-vdso.so.1 \
   "${S}"/tools/vdso_wrap.S

${NM} -D elf-vdso.so.1 | \
   ${AWK} '/__vdso_sigcode/{printf "#define VDSO_SIGCODE_OFFSET 0x%s\n",$1}' \
   >vdso_offsets.h