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 $(call ld-option, --no-eh-frame-hdr) --build-id -n \ 28 $(btildflags-y) -T 29 30ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18 31ccflags-y += -DDISABLE_BRANCH_PROFILING 32 33CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) $(GCC_PLUGINS_CFLAGS) 34KBUILD_CFLAGS += $(DISABLE_LTO) 35KASAN_SANITIZE := n 36UBSAN_SANITIZE := n 37OBJECT_FILES_NON_STANDARD := y 38KCOV_INSTRUMENT := n 39 40CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny -fasynchronous-unwind-tables 41 42ifneq ($(c-gettimeofday-y),) 43 CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y) 44endif 45 46# Clang versions less than 8 do not support -mcmodel=tiny 47ifeq ($(CONFIG_CC_IS_CLANG), y) 48 ifeq ($(shell test $(CONFIG_CLANG_VERSION) -lt 80000; echo $$?),0) 49 CFLAGS_REMOVE_vgettimeofday.o += -mcmodel=tiny 50 endif 51endif 52 53# Disable gcov profiling for VDSO code 54GCOV_PROFILE := n 55 56obj-y += vdso.o 57extra-y += vdso.lds 58CPPFLAGS_vdso.lds += -P -C -U$(ARCH) 59 60# Force dependency (incbin is bad) 61$(obj)/vdso.o : $(obj)/vdso.so 62 63# Link rule for the .so file, .lds has to be first 64$(obj)/vdso.so.dbg: $(obj)/vdso.lds $(obj-vdso) FORCE 65 $(call if_changed,vdsold_and_vdso_check) 66 67# Strip rule for the .so file 68$(obj)/%.so: OBJCOPYFLAGS := -S 69$(obj)/%.so: $(obj)/%.so.dbg FORCE 70 $(call if_changed,objcopy) 71 72# Generate VDSO offsets using helper script 73gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh 74quiet_cmd_vdsosym = VDSOSYM $@ 75 cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@ 76 77include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE 78 $(call if_changed,vdsosym) 79 80# Actual build commands 81quiet_cmd_vdsold_and_vdso_check = LD $@ 82 cmd_vdsold_and_vdso_check = $(cmd_ld); $(cmd_vdso_check) 83 84# Install commands for the unstripped file 85quiet_cmd_vdso_install = INSTALL $@ 86 cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@ 87 88vdso.so: $(obj)/vdso.so.dbg 89 @mkdir -p $(MODLIB)/vdso 90 $(call cmd,vdso_install) 91 92vdso_install: vdso.so 93