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# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before 10# the inclusion of generic Makefile. 11ARCH_REL_TYPE_ABS := R_AARCH64_JUMP_SLOT|R_AARCH64_GLOB_DAT|R_AARCH64_ABS64 12include $(srctree)/lib/vdso/Makefile 13 14obj-vdso := vgettimeofday.o note.o sigreturn.o 15 16# Build rules 17targets := $(obj-vdso) vdso.so vdso.so.dbg 18obj-vdso := $(addprefix $(obj)/, $(obj-vdso)) 19 20btildflags-$(CONFIG_ARM64_BTI_KERNEL) += -z force-bti 21 22# -Bsymbolic has been added for consistency with arm, the compat vDSO and 23# potential future proofing if we end up with internal calls to the exported 24# routines, as x86 does (see 6f121e548f83 ("x86, vdso: Reimplement vdso.so 25# preparation in build-time C")). 26ldflags-y := -shared -nostdlib -soname=linux-vdso.so.1 --hash-style=sysv \ 27 -Bsymbolic --eh-frame-hdr --build-id -n $(btildflags-y) -T 28 29ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18 30ccflags-y += -DDISABLE_BRANCH_PROFILING 31 32CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) 33KBUILD_CFLAGS += $(DISABLE_LTO) 34KASAN_SANITIZE := n 35UBSAN_SANITIZE := n 36OBJECT_FILES_NON_STANDARD := y 37KCOV_INSTRUMENT := n 38 39CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny -fasynchronous-unwind-tables 40 41ifneq ($(c-gettimeofday-y),) 42 CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y) 43endif 44 45# Clang versions less than 8 do not support -mcmodel=tiny 46ifeq ($(CONFIG_CC_IS_CLANG), y) 47 ifeq ($(shell test $(CONFIG_CLANG_VERSION) -lt 80000; echo $$?),0) 48 CFLAGS_REMOVE_vgettimeofday.o += -mcmodel=tiny 49 endif 50endif 51 52# Disable gcov profiling for VDSO code 53GCOV_PROFILE := n 54 55obj-y += vdso.o 56extra-y += vdso.lds 57CPPFLAGS_vdso.lds += -P -C -U$(ARCH) 58 59# Force dependency (incbin is bad) 60$(obj)/vdso.o : $(obj)/vdso.so 61 62# Link rule for the .so file, .lds has to be first 63$(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 := $(srctree)/$(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 83# Install commands for the unstripped file 84quiet_cmd_vdso_install = INSTALL $@ 85 cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@ 86 87vdso.so: $(obj)/vdso.so.dbg 88 @mkdir -p $(MODLIB)/vdso 89 $(call cmd,vdso_install) 90 91vdso_install: vdso.so 92