linux/scripts/link-vmlinux.sh
Kees Cook 8959e39272 kbuild: Parameterize kallsyms generation and correct reporting
When kallsyms generation happens, temporary vmlinux outputs are linked
but the quiet make output didn't report it, giving the impression that
the prior command is taking longer than expected.

Instead, report the linking step explicitly. While at it, this
consolidates the repeated "kallsyms generation step" into a single
function and removes the existing copy/pasting.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-21 21:05:21 +09:00

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#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
#
# link vmlinux
#
# vmlinux is linked from the objects selected by $(KBUILD_VMLINUX_OBJS) and
# $(KBUILD_VMLINUX_LIBS). Most are built-in.a files from top-level directories
# in the kernel tree, others are specified in arch/$(ARCH)/Makefile.
# $(KBUILD_VMLINUX_LIBS) are archives which are linked conditionally
# (not within --whole-archive), and do not require symbol indexes added.
#
# vmlinux
# ^
# |
# +--< $(KBUILD_VMLINUX_OBJS)
# | +--< init/built-in.a drivers/built-in.a mm/built-in.a + more
# |
# +--< $(KBUILD_VMLINUX_LIBS)
# | +--< lib/lib.a + more
# |
# +-< ${kallsymso} (see description in KALLSYMS section)
#
# vmlinux version (uname -v) cannot be updated during normal
# descending-into-subdirs phase since we do not yet know if we need to
# update vmlinux.
# Therefore this step is delayed until just before final link of vmlinux.
#
# System.map is generated to document addresses of all kernel symbols
# Error out on error
set -e
# Nice output in kbuild format
# Will be supressed by "make -s"
info()
{
if [ "${quiet}" != "silent_" ]; then
printf " %-7s %s\n" "${1}" "${2}"
fi
}
# Link of vmlinux.o used for section mismatch analysis
# ${1} output file
modpost_link()
{
local objects
objects="--whole-archive \
${KBUILD_VMLINUX_OBJS} \
--no-whole-archive \
--start-group \
${KBUILD_VMLINUX_LIBS} \
--end-group"
${LD} ${KBUILD_LDFLAGS} -r -o ${1} ${objects}
}
# Link of vmlinux
# ${1} - optional extra .o files
# ${2} - output file
vmlinux_link()
{
info LD ${2}
local lds="${objtree}/${KBUILD_LDS}"
local objects
if [ "${SRCARCH}" != "um" ]; then
objects="--whole-archive \
${KBUILD_VMLINUX_OBJS} \
--no-whole-archive \
--start-group \
${KBUILD_VMLINUX_LIBS} \
--end-group \
${1}"
${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} -o ${2} \
-T ${lds} ${objects}
else
objects="-Wl,--whole-archive \
${KBUILD_VMLINUX_OBJS} \
-Wl,--no-whole-archive \
-Wl,--start-group \
${KBUILD_VMLINUX_LIBS} \
-Wl,--end-group \
${1}"
${CC} ${CFLAGS_vmlinux} -o ${2} \
-Wl,-T,${lds} \
${objects} \
-lutil -lrt -lpthread
rm -f linux
fi
}
# generate .BTF typeinfo from DWARF debuginfo
gen_btf()
{
local pahole_ver;
if ! [ -x "$(command -v ${PAHOLE})" ]; then
info "BTF" "${1}: pahole (${PAHOLE}) is not available"
return 0
fi
pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/')
if [ "${pahole_ver}" -lt "113" ]; then
info "BTF" "${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.13"
return 0
fi
info "BTF" ${1}
LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${1}
}
# Create ${2} .o file with all symbols from the ${1} object file
kallsyms()
{
info KSYM ${2}
local kallsymopt;
if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
kallsymopt="${kallsymopt} --all-symbols"
fi
if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then
kallsymopt="${kallsymopt} --absolute-percpu"
fi
if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then
kallsymopt="${kallsymopt} --base-relative"
fi
local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \
${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
local afile="`basename ${2} .o`.S"
${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${afile}
${CC} ${aflags} -c -o ${2} ${afile}
}
# Perform one step in kallsyms generation, including temporary linking of
# vmlinux.
kallsyms_step()
{
kallsymso_prev=${kallsymso}
kallsymso=.tmp_kallsyms${1}.o
kallsyms_vmlinux=.tmp_vmlinux${1}
vmlinux_link "${kallsymso_prev}" ${kallsyms_vmlinux}
kallsyms ${kallsyms_vmlinux} ${kallsymso}
}
# Create map file with all symbols from ${1}
# See mksymap for additional details
mksysmap()
{
${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
}
sortextable()
{
${objtree}/scripts/sortextable ${1}
}
# Delete output files in case of error
cleanup()
{
rm -f .tmp_System.map
rm -f .tmp_kallsyms*
rm -f .tmp_vmlinux*
rm -f System.map
rm -f vmlinux
rm -f vmlinux.o
}
on_exit()
{
if [ $? -ne 0 ]; then
cleanup
fi
}
trap on_exit EXIT
on_signals()
{
exit 1
}
trap on_signals HUP INT QUIT TERM
#
#
# Use "make V=1" to debug this script
case "${KBUILD_VERBOSE}" in
*1*)
set -x
;;
esac
if [ "$1" = "clean" ]; then
cleanup
exit 0
fi
# We need access to CONFIG_ symbols
. include/config/auto.conf
# Update version
info GEN .version
if [ -r .version ]; then
VERSION=$(expr 0$(cat .version) + 1)
echo $VERSION > .version
else
rm -f .version
echo 1 > .version
fi;
# final build of init/
${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init
#link vmlinux.o
info LD vmlinux.o
modpost_link vmlinux.o
# modpost vmlinux.o to check for section mismatches
${MAKE} -f "${srctree}/scripts/Makefile.modpost" MODPOST_VMLINUX=1
info MODINFO modules.builtin.modinfo
${OBJCOPY} -j .modinfo -O binary vmlinux.o modules.builtin.modinfo
kallsymso=""
kallsymso_prev=""
kallsyms_vmlinux=""
if [ -n "${CONFIG_KALLSYMS}" ]; then
# kallsyms support
# Generate section listing all symbols and add it into vmlinux
# It's a three step process:
# 1) Link .tmp_vmlinux1 so it has all symbols and sections,
# but __kallsyms is empty.
# Running kallsyms on that gives us .tmp_kallsyms1.o with
# the right size
# 2) Link .tmp_vmlinux2 so it now has a __kallsyms section of
# the right size, but due to the added section, some
# addresses have shifted.
# From here, we generate a correct .tmp_kallsyms2.o
# 3) That link may have expanded the kernel image enough that
# more linker branch stubs / trampolines had to be added, which
# introduces new names, which further expands kallsyms. Do another
# pass if that is the case. In theory it's possible this results
# in even more stubs, but unlikely.
# KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
# other bugs.
# 4) The correct ${kallsymso} is linked into the final vmlinux.
#
# a) Verify that the System.map from vmlinux matches the map from
# ${kallsymso}.
kallsyms_step 1
kallsyms_step 2
# step 3
size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso_prev})
size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
kallsyms_step 3
fi
fi
vmlinux_link "${kallsymso}" vmlinux
if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then
gen_btf vmlinux
fi
if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then
info SORTEX vmlinux
sortextable vmlinux
fi
info SYSMAP System.map
mksysmap vmlinux System.map
# step a (see comment above)
if [ -n "${CONFIG_KALLSYMS}" ]; then
mksysmap ${kallsyms_vmlinux} .tmp_System.map
if ! cmp -s System.map .tmp_System.map; then
echo >&2 Inconsistent kallsyms data
echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround
exit 1
fi
fi