[linux-2.6-block.git] / scripts / link-vmlinux.sh

#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
#
# link vmlinux
#
# vmlinux is linked from the objects in vmlinux.a and $(KBUILD_VMLINUX_LIBS).
# vmlinux.a contains objects that are linked unconditionally.
# $(KBUILD_VMLINUX_LIBS) are archives which are linked conditionally
# (not within --whole-archive), and do not require symbol indexes added.
#
# vmlinux
#   ^
#   |
#   +--< vmlinux.a
#   |
#   +--< $(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

LD="$1"
KBUILD_LDFLAGS="$2"
LDFLAGS_vmlinux="$3"
VMLINUX="$4"

is_enabled() {
	grep -q "^$1=y" include/config/auto.conf
}

# Nice output in kbuild format
# Will be supressed by "make -s"
info()
{
	printf "  %-7s %s\n" "${1}" "${2}"
}

# Link of vmlinux
# ${1} - output file
vmlinux_link()
{
	local output=${1}
	local objs
	local libs
	local ld
	local ldflags
	local ldlibs

	info LD ${output}

	# skip output file argument
	shift

	if is_enabled CONFIG_LTO_CLANG || is_enabled CONFIG_X86_KERNEL_IBT; then
		# Use vmlinux.o instead of performing the slow LTO link again.
		objs=vmlinux.o
		libs=
	else
		objs=vmlinux.a
		libs="${KBUILD_VMLINUX_LIBS}"
	fi

	if is_enabled CONFIG_GENERIC_BUILTIN_DTB; then
		objs="${objs} .builtin-dtbs.o"
	fi

	if is_enabled CONFIG_MODULES; then
		objs="${objs} .vmlinux.export.o"
	fi

	objs="${objs} init/version-timestamp.o"

	if [ "${SRCARCH}" = "um" ]; then
		wl=-Wl,
		ld="${CC}"
		ldflags="${CFLAGS_vmlinux}"
		ldlibs="-lutil -lrt -lpthread"
	else
		wl=
		ld="${LD}"
		ldflags="${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux}"
		ldlibs=
	fi

	ldflags="${ldflags} ${wl}--script=${objtree}/${KBUILD_LDS}"

	# The kallsyms linking does not need debug symbols included.
	if [ -n "${strip_debug}" ] ; then
		ldflags="${ldflags} ${wl}--strip-debug"
	fi

	if [ -n "${generate_map}" ];  then
		ldflags="${ldflags} ${wl}-Map=vmlinux.map"
	fi

	${ld} ${ldflags} -o ${output}					\
		${wl}--whole-archive ${objs} ${wl}--no-whole-archive	\
		${wl}--start-group ${libs} ${wl}--end-group		\
		${kallsymso} ${btf_vmlinux_bin_o} ${arch_vmlinux_o} ${ldlibs}
}

# generate .BTF typeinfo from DWARF debuginfo
# ${1} - vmlinux image
gen_btf()
{
	local btf_data=${1}.btf.o

	info BTF "${btf_data}"
	LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${1}

	# Create ${btf_data} which contains just .BTF section but no symbols. Add
	# SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all
	# deletes all symbols including __start_BTF and __stop_BTF, which will
	# be redefined in the linker script. Add 2>/dev/null to suppress GNU
	# objcopy warnings: "empty loadable segment detected at ..."
	${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \
		--strip-all ${1} "${btf_data}" 2>/dev/null
	# Change e_type to ET_REL so that it can be used to link final vmlinux.
	# GNU ld 2.35+ and lld do not allow an ET_EXEC input.
	if is_enabled CONFIG_CPU_BIG_ENDIAN; then
		et_rel='\0\1'
	else
		et_rel='\1\0'
	fi
	printf "${et_rel}" | dd of="${btf_data}" conv=notrunc bs=1 seek=16 status=none

	btf_vmlinux_bin_o=${btf_data}
}

# Create ${2}.o file with all symbols from the ${1} object file
kallsyms()
{
	local kallsymopt;

	if is_enabled CONFIG_KALLSYMS_ALL; then
		kallsymopt="${kallsymopt} --all-symbols"
	fi

	info KSYMS "${2}.S"
	scripts/kallsyms ${kallsymopt} "${1}" > "${2}.S"

	info AS "${2}.o"
	${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \
	      ${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} -c -o "${2}.o" "${2}.S"

	kallsymso=${2}.o
}

# Perform kallsyms for the given temporary vmlinux.
sysmap_and_kallsyms()
{
	mksysmap "${1}" "${1}.syms"
	kallsyms "${1}.syms" "${1}.kallsyms"

	kallsyms_sysmap=${1}.syms
}

# Create map file with all symbols from ${1}
# See mksymap for additional details
mksysmap()
{
	info NM ${2}
	${NM} -n "${1}" | sed -f "${srctree}/scripts/mksysmap" > "${2}"
}

sorttable()
{
	${NM} -S ${1} > .tmp_vmlinux.nm-sort
	${objtree}/scripts/sorttable -s .tmp_vmlinux.nm-sort ${1}
}

cleanup()
{
	rm -f .btf.*
	rm -f .tmp_vmlinux.nm-sort
	rm -f System.map
	rm -f vmlinux
	rm -f vmlinux.map
}

# Use "make V=1" to debug this script
case "${KBUILD_VERBOSE}" in
*1*)
	set -x
	;;
esac

if [ "$1" = "clean" ]; then
	cleanup
	exit 0
fi

${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init init/version-timestamp.o

arch_vmlinux_o=
if is_enabled CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX; then
	arch_vmlinux_o=arch/${SRCARCH}/tools/vmlinux.arch.o
fi

btf_vmlinux_bin_o=
kallsymso=
strip_debug=
generate_map=

if is_enabled CONFIG_KALLSYMS; then
	true > .tmp_vmlinux0.syms
	kallsyms .tmp_vmlinux0.syms .tmp_vmlinux0.kallsyms
fi

if is_enabled CONFIG_KALLSYMS || is_enabled CONFIG_DEBUG_INFO_BTF; then

	# The kallsyms linking does not need debug symbols, but the BTF does.
	if ! is_enabled CONFIG_DEBUG_INFO_BTF; then
		strip_debug=1
	fi

	vmlinux_link .tmp_vmlinux1
fi

if is_enabled CONFIG_DEBUG_INFO_BTF; then
	if ! gen_btf .tmp_vmlinux1; then
		echo >&2 "Failed to generate BTF for vmlinux"
		echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF"
		exit 1
	fi
fi

if is_enabled CONFIG_KALLSYMS; then

	# kallsyms support
	# Generate section listing all symbols and add it into vmlinux
	# It's a four step process:
	# 0)  Generate a dummy __kallsyms with empty symbol list.
	# 1)  Link .tmp_vmlinux1.kallsyms so it has all symbols and sections,
	#     with a dummy __kallsyms.
	#     Running kallsyms on that gives us .tmp_vmlinux1.kallsyms.o with
	#     the right size
	# 2)  Link .tmp_vmlinux2.kallsyms 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_vmlinux2.kallsyms.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}.

	# The kallsyms linking does not need debug symbols included.
	strip_debug=1

	sysmap_and_kallsyms .tmp_vmlinux1
	size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})

	vmlinux_link .tmp_vmlinux2
	sysmap_and_kallsyms .tmp_vmlinux2
	size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})

	if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
		vmlinux_link .tmp_vmlinux3
		sysmap_and_kallsyms .tmp_vmlinux3
	fi
fi

strip_debug=

if is_enabled CONFIG_VMLINUX_MAP; then
	generate_map=1
fi

vmlinux_link "${VMLINUX}"

# fill in BTF IDs
if is_enabled CONFIG_DEBUG_INFO_BTF; then
	info BTFIDS "${VMLINUX}"
	RESOLVE_BTFIDS_ARGS=""
	if is_enabled CONFIG_WERROR; then
		RESOLVE_BTFIDS_ARGS=" --fatal_warnings "
	fi
	${RESOLVE_BTFIDS} ${RESOLVE_BTFIDS_ARGS} "${VMLINUX}"
fi

mksysmap "${VMLINUX}" System.map

if is_enabled CONFIG_BUILDTIME_TABLE_SORT; then
	info SORTTAB "${VMLINUX}"
	if ! sorttable "${VMLINUX}"; then
		echo >&2 Failed to sort kernel tables
		exit 1
	fi
fi

# step a (see comment above)
if is_enabled CONFIG_KALLSYMS; then
	if ! cmp -s System.map "${kallsyms_sysmap}"; then
		echo >&2 Inconsistent kallsyms data
		echo >&2 'Try "make KALLSYMS_EXTRA_PASS=1" as a workaround'
		exit 1
	fi
fi

# For fixdep
echo "${VMLINUX}: $0" > ".${VMLINUX}.d"
Commit	Line	Data
	1	#!/bin/sh
	2	# SPDX-License-Identifier: GPL-2.0
	3	#
	4	# link vmlinux
	5	#
	6	# vmlinux is linked from the objects in vmlinux.a and $(KBUILD_VMLINUX_LIBS).
	7	# vmlinux.a contains objects that are linked unconditionally.
	8	# $(KBUILD_VMLINUX_LIBS) are archives which are linked conditionally
	9	# (not within --whole-archive), and do not require symbol indexes added.
	10	#
	11	# vmlinux
	12	# ^
	13	# \|
	14	# +--< vmlinux.a
	15	# \|
	16	# +--< $(KBUILD_VMLINUX_LIBS)
	17	# \| +--< lib/lib.a + more
	18	# \|
	19	# +-< ${kallsymso} (see description in KALLSYMS section)
	20	#
	21	# vmlinux version (uname -v) cannot be updated during normal
	22	# descending-into-subdirs phase since we do not yet know if we need to
	23	# update vmlinux.
	24	# Therefore this step is delayed until just before final link of vmlinux.
	25	#
	26	# System.map is generated to document addresses of all kernel symbols
	27
	28	# Error out on error
	29	set -e
	30
	31	LD="$1"
	32	KBUILD_LDFLAGS="$2"
	33	LDFLAGS_vmlinux="$3"
	34	VMLINUX="$4"
	35
	36	is_enabled() {
	37	grep -q "^$1=y" include/config/auto.conf
	38	}
	39
	40	# Nice output in kbuild format
	41	# Will be supressed by "make -s"
	42	info()
	43	{
	44	printf " %-7s %s\n" "${1}" "${2}"
	45	}
	46
	47	# Link of vmlinux
	48	# ${1} - output file
	49	vmlinux_link()
	50	{
	51	local output=${1}
	52	local objs
	53	local libs
	54	local ld
	55	local ldflags
	56	local ldlibs
	57
	58	info LD ${output}
	59
	60	# skip output file argument
	61	shift
	62
	63	if is_enabled CONFIG_LTO_CLANG \|\| is_enabled CONFIG_X86_KERNEL_IBT; then
	64	# Use vmlinux.o instead of performing the slow LTO link again.
	65	objs=vmlinux.o
	66	libs=
	67	else
	68	objs=vmlinux.a
	69	libs="${KBUILD_VMLINUX_LIBS}"
	70	fi
	71
	72	if is_enabled CONFIG_GENERIC_BUILTIN_DTB; then
	73	objs="${objs} .builtin-dtbs.o"
	74	fi
	75
	76	if is_enabled CONFIG_MODULES; then
	77	objs="${objs} .vmlinux.export.o"
	78	fi
	79
	80	objs="${objs} init/version-timestamp.o"
	81
	82	if [ "${SRCARCH}" = "um" ]; then
	83	wl=-Wl,
	84	ld="${CC}"
	85	ldflags="${CFLAGS_vmlinux}"
	86	ldlibs="-lutil -lrt -lpthread"
	87	else
	88	wl=
	89	ld="${LD}"
	90	ldflags="${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux}"
	91	ldlibs=
	92	fi
	93
	94	ldflags="${ldflags} ${wl}--script=${objtree}/${KBUILD_LDS}"
	95
	96	# The kallsyms linking does not need debug symbols included.
	97	if [ -n "${strip_debug}" ] ; then
	98	ldflags="${ldflags} ${wl}--strip-debug"
	99	fi
	100
	101	if [ -n "${generate_map}" ]; then
	102	ldflags="${ldflags} ${wl}-Map=vmlinux.map"
	103	fi
	104
	105	${ld} ${ldflags} -o ${output} \
	106	${wl}--whole-archive ${objs} ${wl}--no-whole-archive \
	107	${wl}--start-group ${libs} ${wl}--end-group \
	108	${kallsymso} ${btf_vmlinux_bin_o} ${arch_vmlinux_o} ${ldlibs}
	109	}
	110
	111	# generate .BTF typeinfo from DWARF debuginfo
	112	# ${1} - vmlinux image
	113	gen_btf()
	114	{
	115	local btf_data=${1}.btf.o
	116
	117	info BTF "${btf_data}"
	118	LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${1}
	119
	120	# Create ${btf_data} which contains just .BTF section but no symbols. Add
	121	# SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all
	122	# deletes all symbols including __start_BTF and __stop_BTF, which will
	123	# be redefined in the linker script. Add 2>/dev/null to suppress GNU
	124	# objcopy warnings: "empty loadable segment detected at ..."
	125	${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \
	126	--strip-all ${1} "${btf_data}" 2>/dev/null
	127	# Change e_type to ET_REL so that it can be used to link final vmlinux.
	128	# GNU ld 2.35+ and lld do not allow an ET_EXEC input.
	129	if is_enabled CONFIG_CPU_BIG_ENDIAN; then
	130	et_rel='\0\1'
	131	else
	132	et_rel='\1\0'
	133	fi
	134	printf "${et_rel}" \| dd of="${btf_data}" conv=notrunc bs=1 seek=16 status=none
	135
	136	btf_vmlinux_bin_o=${btf_data}
	137	}
	138
	139	# Create ${2}.o file with all symbols from the ${1} object file
	140	kallsyms()
	141	{
	142	local kallsymopt;
	143
	144	if is_enabled CONFIG_KALLSYMS_ALL; then
	145	kallsymopt="${kallsymopt} --all-symbols"
	146	fi
	147
	148	info KSYMS "${2}.S"
	149	scripts/kallsyms ${kallsymopt} "${1}" > "${2}.S"
	150
	151	info AS "${2}.o"
	152	${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \
	153	${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} -c -o "${2}.o" "${2}.S"
	154
	155	kallsymso=${2}.o
	156	}
	157
	158	# Perform kallsyms for the given temporary vmlinux.
	159	sysmap_and_kallsyms()
	160	{
	161	mksysmap "${1}" "${1}.syms"
	162	kallsyms "${1}.syms" "${1}.kallsyms"
	163
	164	kallsyms_sysmap=${1}.syms
	165	}
	166
	167	# Create map file with all symbols from ${1}
	168	# See mksymap for additional details
	169	mksysmap()
	170	{
	171	info NM ${2}
	172	${NM} -n "${1}" \| sed -f "${srctree}/scripts/mksysmap" > "${2}"
	173	}
	174
	175	sorttable()
	176	{
	177	${NM} -S ${1} > .tmp_vmlinux.nm-sort
	178	${objtree}/scripts/sorttable -s .tmp_vmlinux.nm-sort ${1}
	179	}
	180
	181	cleanup()
	182	{
	183	rm -f .btf.*
	184	rm -f .tmp_vmlinux.nm-sort
	185	rm -f System.map
	186	rm -f vmlinux
	187	rm -f vmlinux.map
	188	}
	189
	190	# Use "make V=1" to debug this script
	191	case "${KBUILD_VERBOSE}" in
	192	1)
	193	set -x
	194	;;
	195	esac
	196
	197	if [ "$1" = "clean" ]; then
	198	cleanup
	199	exit 0
	200	fi
	201
	202	${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init init/version-timestamp.o
	203
	204	arch_vmlinux_o=
	205	if is_enabled CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX; then
	206	arch_vmlinux_o=arch/${SRCARCH}/tools/vmlinux.arch.o
	207	fi
	208
	209	btf_vmlinux_bin_o=
	210	kallsymso=
	211	strip_debug=
	212	generate_map=
	213
	214	if is_enabled CONFIG_KALLSYMS; then
	215	true > .tmp_vmlinux0.syms
	216	kallsyms .tmp_vmlinux0.syms .tmp_vmlinux0.kallsyms
	217	fi
	218
	219	if is_enabled CONFIG_KALLSYMS \|\| is_enabled CONFIG_DEBUG_INFO_BTF; then
	220
	221	# The kallsyms linking does not need debug symbols, but the BTF does.
	222	if ! is_enabled CONFIG_DEBUG_INFO_BTF; then
	223	strip_debug=1
	224	fi
	225
	226	vmlinux_link .tmp_vmlinux1
	227	fi
	228
	229	if is_enabled CONFIG_DEBUG_INFO_BTF; then
	230	if ! gen_btf .tmp_vmlinux1; then
	231	echo >&2 "Failed to generate BTF for vmlinux"
	232	echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF"
	233	exit 1
	234	fi
	235	fi
	236
	237	if is_enabled CONFIG_KALLSYMS; then
	238
	239	# kallsyms support
	240	# Generate section listing all symbols and add it into vmlinux
	241	# It's a four step process:
	242	# 0) Generate a dummy __kallsyms with empty symbol list.
	243	# 1) Link .tmp_vmlinux1.kallsyms so it has all symbols and sections,
	244	# with a dummy __kallsyms.
	245	# Running kallsyms on that gives us .tmp_vmlinux1.kallsyms.o with
	246	# the right size
	247	# 2) Link .tmp_vmlinux2.kallsyms so it now has a __kallsyms section of
	248	# the right size, but due to the added section, some
	249	# addresses have shifted.
	250	# From here, we generate a correct .tmp_vmlinux2.kallsyms.o
	251	# 3) That link may have expanded the kernel image enough that
	252	# more linker branch stubs / trampolines had to be added, which
	253	# introduces new names, which further expands kallsyms. Do another
	254	# pass if that is the case. In theory it's possible this results
	255	# in even more stubs, but unlikely.
	256	# KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
	257	# other bugs.
	258	# 4) The correct ${kallsymso} is linked into the final vmlinux.
	259	#
	260	# a) Verify that the System.map from vmlinux matches the map from
	261	# ${kallsymso}.
	262
	263	# The kallsyms linking does not need debug symbols included.
	264	strip_debug=1
	265
	266	sysmap_and_kallsyms .tmp_vmlinux1
	267	size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
	268
	269	vmlinux_link .tmp_vmlinux2
	270	sysmap_and_kallsyms .tmp_vmlinux2
	271	size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
	272
	273	if [ $size1 -ne $size2 ] \|\| [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
	274	vmlinux_link .tmp_vmlinux3
	275	sysmap_and_kallsyms .tmp_vmlinux3
	276	fi
	277	fi
	278
	279	strip_debug=
	280
	281	if is_enabled CONFIG_VMLINUX_MAP; then
	282	generate_map=1
	283	fi
	284
	285	vmlinux_link "${VMLINUX}"
	286
	287	# fill in BTF IDs
	288	if is_enabled CONFIG_DEBUG_INFO_BTF; then
	289	info BTFIDS "${VMLINUX}"
	290	RESOLVE_BTFIDS_ARGS=""
	291	if is_enabled CONFIG_WERROR; then
	292	RESOLVE_BTFIDS_ARGS=" --fatal_warnings "
	293	fi
	294	${RESOLVE_BTFIDS} ${RESOLVE_BTFIDS_ARGS} "${VMLINUX}"
	295	fi
	296
	297	mksysmap "${VMLINUX}" System.map
	298
	299	if is_enabled CONFIG_BUILDTIME_TABLE_SORT; then
	300	info SORTTAB "${VMLINUX}"
	301	if ! sorttable "${VMLINUX}"; then
	302	echo >&2 Failed to sort kernel tables
	303	exit 1
	304	fi
	305	fi
	306
	307	# step a (see comment above)
	308	if is_enabled CONFIG_KALLSYMS; then
	309	if ! cmp -s System.map "${kallsyms_sysmap}"; then
	310	echo >&2 Inconsistent kallsyms data
	311	echo >&2 'Try "make KALLSYMS_EXTRA_PASS=1" as a workaround'
	312	exit 1
	313	fi
	314	fi
	315
	316	# For fixdep
	317	echo "${VMLINUX}: $0" > ".${VMLINUX}.d"