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) -T 28 29ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18 30ccflags-y += -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO 31 32# -Wmissing-prototypes and -Wmissing-declarations are removed from 33# the CFLAGS of vgettimeofday.c to make possible to build the 34# kernel with CONFIG_WERROR enabled. 35CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) $(GCC_PLUGINS_CFLAGS) \ 36 $(CC_FLAGS_LTO) -Wmissing-prototypes -Wmissing-declarations 37KASAN_SANITIZE := n 38KCSAN_SANITIZE := n 39UBSAN_SANITIZE := n 40OBJECT_FILES_NON_STANDARD := y 41KCOV_INSTRUMENT := n 42 43CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny -fasynchronous-unwind-tables 44 45ifneq ($(c-gettimeofday-y),) 46 CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y) 47endif 48 49# Disable gcov profiling for VDSO code 50GCOV_PROFILE := n 51 52targets += vdso.lds 53CPPFLAGS_vdso.lds += -P -C -U$(ARCH) 54 55# Force dependency (incbin is bad) 56$(obj)/vdso.o : $(obj)/vdso.so 57 58# Link rule for the .so file, .lds has to be first 59$(obj)/vdso.so.dbg: $(obj)/vdso.lds $(obj-vdso) FORCE 60 $(call if_changed,vdsold_and_vdso_check) 61 62# Strip rule for the .so file 63$(obj)/%.so: OBJCOPYFLAGS := -S 64$(obj)/%.so: $(obj)/%.so.dbg FORCE 65 $(call if_changed,objcopy) 66 67# Generate VDSO offsets using helper script 68gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh 69quiet_cmd_vdsosym = VDSOSYM $@ 70 cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@ 71 72include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE 73 $(call if_changed,vdsosym) 74 75# Actual build commands 76quiet_cmd_vdsold_and_vdso_check = LD $@ 77 cmd_vdsold_and_vdso_check = $(cmd_ld); $(cmd_vdso_check) 78 79# Install commands for the unstripped file 80quiet_cmd_vdso_install = INSTALL $@ 81 cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@ 82 83vdso.so: $(obj)/vdso.so.dbg 84 @mkdir -p $(MODLIB)/vdso 85 $(call cmd,vdso_install) 86 87vdso_install: vdso.so 88