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 \ 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) $(CC_FLAGS_CFI) \ 42 -Wmissing-prototypes -Wmissing-declarations 43 44CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny -fasynchronous-unwind-tables 45 46ifneq ($(c-gettimeofday-y),) 47 CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y) 48endif 49 50targets += vdso.lds 51CPPFLAGS_vdso.lds += -P -C -U$(ARCH) 52 53# Link rule for the .so file, .lds has to be first 54$(obj)/vdso.so.dbg: $(obj)/vdso.lds $(obj-vdso) FORCE 55 $(call if_changed,vdsold_and_vdso_check) 56 57# Strip rule for the .so file 58$(obj)/%.so: OBJCOPYFLAGS := -S 59$(obj)/%.so: $(obj)/%.so.dbg FORCE 60 $(call if_changed,objcopy) 61 62# Generate VDSO offsets using helper script 63gen-vdsosym := $(src)/gen_vdso_offsets.sh 64quiet_cmd_vdsosym = VDSOSYM $@ 65 cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@ 66 67include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE 68 $(call if_changed,vdsosym) 69 70# Actual build commands 71quiet_cmd_vdsold_and_vdso_check = LD $@ 72 cmd_vdsold_and_vdso_check = $(cmd_ld); $(cmd_vdso_check) 73