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 vgetrandom.o vgetrandom-chacha.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 to make possible to build the kernel with CONFIG_WERROR enabled. 38CC_FLAGS_REMOVE_VDSO := $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) \ 39 $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) \ 40 $(CC_FLAGS_LTO) $(CC_FLAGS_CFI) \ 41 -Wmissing-prototypes -Wmissing-declarations 42 43CC_FLAGS_ADD_VDSO := -O2 -mcmodel=tiny -fasynchronous-unwind-tables 44 45CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_REMOVE_VDSO) 46CFLAGS_REMOVE_vgetrandom.o = $(CC_FLAGS_REMOVE_VDSO) 47 48CFLAGS_vgettimeofday.o = $(CC_FLAGS_ADD_VDSO) 49CFLAGS_vgetrandom.o = $(CC_FLAGS_ADD_VDSO) 50 51ifneq ($(c-gettimeofday-y),) 52 CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y) 53endif 54 55ifneq ($(c-getrandom-y),) 56 CFLAGS_vgetrandom.o += -include $(c-getrandom-y) 57endif 58 59targets += vdso.lds 60CPPFLAGS_vdso.lds += -P -C -U$(ARCH) 61 62# Link rule for the .so file, .lds has to be first 63$(obj)/vdso.so.dbg: $(obj)/vdso.lds $(obj-vdso) FORCE 64 $(call if_changed,vdsold_and_vdso_check) 65 66# Strip rule for the .so file 67$(obj)/%.so: OBJCOPYFLAGS := -S 68$(obj)/%.so: $(obj)/%.so.dbg FORCE 69 $(call if_changed,objcopy) 70 71# Generate VDSO offsets using helper script 72gen-vdsosym := $(src)/gen_vdso_offsets.sh 73quiet_cmd_vdsosym = VDSOSYM $@ 74 cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@ 75 76include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE 77 $(call if_changed,vdsosym) 78 79# Actual build commands 80quiet_cmd_vdsold_and_vdso_check = LD $@ 81 cmd_vdsold_and_vdso_check = $(cmd_ld); $(cmd_vdso_check) 82