1# SPDX-License-Identifier: GPL-2.0-only 2 3# Include the generic Makefile to check the built vdso. 4include $(srctree)/lib/vdso/Makefile 5 6# Symbols present in the vdso 7vdso-syms += rt_sigreturn 8vdso-syms += vgettimeofday 9 10# Files to link into the vdso 11obj-vdso = $(patsubst %, %.o, $(vdso-syms)) note.o 12 13ifneq ($(c-gettimeofday-y),) 14 CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y) 15endif 16 17ccflags-y := -fno-stack-protector -DBUILD_VDSO32 18 19# Build rules 20targets := $(obj-vdso) vdso.so vdso.so.dbg vdso.lds vdso-dummy.o 21obj-vdso := $(addprefix $(obj)/, $(obj-vdso)) 22 23obj-y += vdso.o vdso-syms.o 24CPPFLAGS_vdso.lds += -P -C -U$(ARCH) 25 26# Force dependency 27$(obj)/vdso.o: $(obj)/vdso.so 28 29SYSCFLAGS_vdso.so.dbg = $(c_flags) 30$(obj)/vdso.so.dbg: $(obj)/vdso.lds $(obj-vdso) FORCE 31 $(call if_changed,vdsold) 32SYSCFLAGS_vdso.so.dbg = -shared -s -Wl,-soname=linux-vdso.so.1 \ 33 -Wl,--build-id=sha1 -Wl,--hash-style=both 34 35$(obj)/vdso-syms.S: $(obj)/vdso.so FORCE 36 $(call if_changed,so2s) 37 38# strip rule for the .so file 39$(obj)/%.so: OBJCOPYFLAGS := -S 40$(obj)/%.so: $(obj)/%.so.dbg FORCE 41 $(call if_changed,objcopy) 42 43# actual build commands 44# The DSO images are built using a special linker script 45# Make sure only to export the intended __vdso_xxx symbol offsets. 46quiet_cmd_vdsold = VDSOLD $@ 47 cmd_vdsold = $(CC) $(KBUILD_CFLAGS) $(call cc-option, -no-pie) -nostdlib -nostartfiles $(SYSCFLAGS_$(@F)) \ 48 -Wl,-T,$(filter-out FORCE,$^) -o $@.tmp && \ 49 $(CROSS_COMPILE)objcopy \ 50 $(patsubst %, -G __vdso_%, $(vdso-syms)) $@.tmp $@ && \ 51 rm $@.tmp 52 53# Extracts symbol offsets from the VDSO, converting them into an assembly file 54# that contains the same symbols at the same offsets. 55quiet_cmd_so2s = SO2S $@ 56 cmd_so2s = $(NM) -D $< | $(src)/so2s.sh > $@ 57