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