projects/linux·blob master · refs

55 lines · 1.8 KiB

1# SPDX-License-Identifier: GPL-2.0-only
2
3# Include the generic Makefile to check the built vdso.
4include $(srctree)/lib/vdso/Makefile.include
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 > $@