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 -soname=linux-vdso.so.1 --hash-style=sysv \ 27 -Bsymbolic --build-id=sha1 -n $(btildflags-y) 28 29ifdef CONFIG_LD_ORPHAN_WARN 30 ldflags-y += --orphan-handling=warn 31endif 32 33ldflags-y += -T 34 35ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18 36ccflags-y += -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO 37 38# -Wmissing-prototypes and -Wmissing-declarations are removed from 39# the CFLAGS of vgettimeofday.c to make possible to build the 40# kernel with CONFIG_WERROR enabled. 41CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) \ 42 $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) \ 43 $(CC_FLAGS_LTO) -Wmissing-prototypes -Wmissing-declarations 44KASAN_SANITIZE := n 45KCSAN_SANITIZE := n 46UBSAN_SANITIZE := n 47OBJECT_FILES_NON_STANDARD := y 48KCOV_INSTRUMENT := n 49 50CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny -fasynchronous-unwind-tables 51 52ifneq ($(c-gettimeofday-y),) 53 CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y) 54endif 55 56# Disable gcov profiling for VDSO code 57GCOV_PROFILE := n 58 59targets += vdso.lds 60CPPFLAGS_vdso.lds += -P -C -U$(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 := $(srctree)/$(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