1# SPDX-License-Identifier: GPL-2.0
2#
3# Building a vDSO image for AArch64.
4#
5# Author: Will Deacon <will.deacon@arm.com>
6# Heavily based on the vDSO Makefiles for other archs.
7#
8
9# Include the generic Makefile to check the built vdso.
10include $(srctree)/lib/vdso/Makefile
11
12obj-vdso := vgettimeofday.o note.o sigreturn.o
13
14# Build rules
15targets := $(obj-vdso) vdso.so vdso.so.dbg
16obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
17
18btildflags-$(CONFIG_ARM64_BTI_KERNEL) += -z force-bti
19
20# -Bsymbolic has been added for consistency with arm, the compat vDSO and
21# potential future proofing if we end up with internal calls to the exported
22# routines, as x86 does (see 6f121e548f83 ("x86, vdso: Reimplement vdso.so
23# preparation in build-time C")).
24ldflags-y := -shared -soname=linux-vdso.so.1 --hash-style=sysv	\
25	     -Bsymbolic --build-id=sha1 -n $(btildflags-y)
26
27ifdef CONFIG_LD_ORPHAN_WARN
28  ldflags-y += --orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL)
29endif
30
31ldflags-y += -T
32
33ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18
34ccflags-y += -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
35
36# -Wmissing-prototypes and -Wmissing-declarations are removed from
37# the CFLAGS of vgettimeofday.c to make possible to build the
38# kernel with CONFIG_WERROR enabled.
39CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) \
40				$(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) \
41				$(CC_FLAGS_LTO) $(CC_FLAGS_CFI) \
42				-Wmissing-prototypes -Wmissing-declarations
43KASAN_SANITIZE			:= n
44KCSAN_SANITIZE			:= n
45UBSAN_SANITIZE			:= n
46OBJECT_FILES_NON_STANDARD	:= y
47KCOV_INSTRUMENT			:= n
48
49CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny -fasynchronous-unwind-tables
50
51ifneq ($(c-gettimeofday-y),)
52  CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
53endif
54
55# Disable gcov profiling for VDSO code
56GCOV_PROFILE := n
57
58targets += vdso.lds
59CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
60
61# Link rule for the .so file, .lds has to be first
62$(obj)/vdso.so.dbg: $(obj)/vdso.lds $(obj-vdso) FORCE
63	$(call if_changed,vdsold_and_vdso_check)
64
65# Strip rule for the .so file
66$(obj)/%.so: OBJCOPYFLAGS := -S
67$(obj)/%.so: $(obj)/%.so.dbg FORCE
68	$(call if_changed,objcopy)
69
70# Generate VDSO offsets using helper script
71gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh
72quiet_cmd_vdsosym = VDSOSYM $@
73      cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
74
75include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE
76	$(call if_changed,vdsosym)
77
78# Actual build commands
79quiet_cmd_vdsold_and_vdso_check = LD      $@
80      cmd_vdsold_and_vdso_check = $(cmd_ld); $(cmd_vdso_check)
81