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# Disable gcov profiling for VDSO code 27GCOV_PROFILE := n 28KCOV_INSTRUMENT := n 29 30# Force dependency 31$(obj)/vdso.o: $(obj)/vdso.so 32 33SYSCFLAGS_vdso.so.dbg = $(c_flags) 34$(obj)/vdso.so.dbg: $(src)/vdso.lds $(obj-vdso) FORCE 35 $(call if_changed,vdsold) 36SYSCFLAGS_vdso.so.dbg = -shared -s -Wl,-soname=linux-vdso.so.1 \ 37 -Wl,--build-id=sha1 -Wl,--hash-style=both 38 39$(obj)/vdso-syms.S: $(obj)/vdso.so FORCE 40 $(call if_changed,so2s) 41 42# strip rule for the .so file 43$(obj)/%.so: OBJCOPYFLAGS := -S 44$(obj)/%.so: $(obj)/%.so.dbg FORCE 45 $(call if_changed,objcopy) 46 47# actual build commands 48# The DSO images are built using a special linker script 49# Make sure only to export the intended __vdso_xxx symbol offsets. 50quiet_cmd_vdsold = VDSOLD $@ 51 cmd_vdsold = $(CC) $(KBUILD_CFLAGS) $(call cc-option, -no-pie) -nostdlib -nostartfiles $(SYSCFLAGS_$(@F)) \ 52 -Wl,-T,$(filter-out FORCE,$^) -o $@.tmp && \ 53 $(CROSS_COMPILE)objcopy \ 54 $(patsubst %, -G __vdso_%, $(vdso-syms)) $@.tmp $@ && \ 55 rm $@.tmp 56 57# Extracts symbol offsets from the VDSO, converting them into an assembly file 58# that contains the same symbols at the same offsets. 59quiet_cmd_so2s = SO2S $@ 60 cmd_so2s = $(NM) -D $< | $(srctree)/$(src)/so2s.sh > $@ 61 62# install commands for the unstripped file 63quiet_cmd_vdso_install = INSTALL $@ 64 cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@ 65 66vdso.so: $(obj)/vdso.so.dbg 67 @mkdir -p $(MODLIB)/vdso 68 $(call cmd,vdso_install) 69 70vdso_install: vdso.so 71