xref: /openbmc/linux/arch/riscv/kernel/vdso/Makefile (revision fc772314)
1# SPDX-License-Identifier: GPL-2.0-only
2# Copied from arch/tile/kernel/vdso/Makefile
3
4# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before
5# the inclusion of generic Makefile.
6ARCH_REL_TYPE_ABS := R_RISCV_32|R_RISCV_64|R_RISCV_JUMP_SLOT
7include $(srctree)/lib/vdso/Makefile
8# Symbols present in the vdso
9vdso-syms  = rt_sigreturn
10ifdef CONFIG_64BIT
11vdso-syms += vgettimeofday
12endif
13vdso-syms += getcpu
14vdso-syms += flush_icache
15
16# Files to link into the vdso
17obj-vdso = $(patsubst %, %.o, $(vdso-syms)) note.o
18
19ccflags-y := -fno-stack-protector
20
21ifneq ($(c-gettimeofday-y),)
22  CFLAGS_vgettimeofday.o += -fPIC -include $(c-gettimeofday-y)
23endif
24
25# Build rules
26targets := $(obj-vdso) vdso.so vdso.so.dbg vdso.lds vdso-dummy.o
27obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
28
29obj-y += vdso.o vdso-syms.o
30CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
31
32# Disable -pg to prevent insert call site
33CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os
34
35# Disable gcov profiling for VDSO code
36GCOV_PROFILE := n
37KCOV_INSTRUMENT := n
38
39# Force dependency
40$(obj)/vdso.o: $(obj)/vdso.so
41
42# link rule for the .so file, .lds has to be first
43SYSCFLAGS_vdso.so.dbg = $(c_flags)
44$(obj)/vdso.so.dbg: $(src)/vdso.lds $(obj-vdso) FORCE
45	$(call if_changed,vdsold)
46
47# We also create a special relocatable object that should mirror the symbol
48# table and layout of the linked DSO. With ld --just-symbols we can then
49# refer to these symbols in the kernel code rather than hand-coded addresses.
50
51SYSCFLAGS_vdso.so.dbg = -shared -s -Wl,-soname=linux-vdso.so.1 \
52	-Wl,--build-id -Wl,--hash-style=both
53$(obj)/vdso-dummy.o: $(src)/vdso.lds $(obj)/rt_sigreturn.o FORCE
54	$(call if_changed,vdsold)
55
56LDFLAGS_vdso-syms.o := -r --just-symbols
57$(obj)/vdso-syms.o: $(obj)/vdso-dummy.o FORCE
58	$(call if_changed,ld)
59
60# strip rule for the .so file
61$(obj)/%.so: OBJCOPYFLAGS := -S
62$(obj)/%.so: $(obj)/%.so.dbg FORCE
63	$(call if_changed,objcopy)
64
65# actual build commands
66# The DSO images are built using a special linker script
67# Add -lgcc so rv32 gets static muldi3 and lshrdi3 definitions.
68# Make sure only to export the intended __vdso_xxx symbol offsets.
69quiet_cmd_vdsold = VDSOLD  $@
70      cmd_vdsold = $(CC) $(KBUILD_CFLAGS) $(call cc-option, -no-pie) -nostdlib -nostartfiles $(SYSCFLAGS_$(@F)) \
71                           -Wl,-T,$(filter-out FORCE,$^) -o $@.tmp && \
72                   $(CROSS_COMPILE)objcopy \
73                           $(patsubst %, -G __vdso_%, $(vdso-syms)) $@.tmp $@ && \
74                   rm $@.tmp
75
76# install commands for the unstripped file
77quiet_cmd_vdso_install = INSTALL $@
78      cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@
79
80vdso.so: $(obj)/vdso.so.dbg
81	@mkdir -p $(MODLIB)/vdso
82	$(call cmd,vdso_install)
83
84vdso_install: vdso.so
85