xref: /linux/arch/riscv/kernel/compat_vdso/Makefile (revision ff9a79307f89563da6d841da8b7cc4a0afceb0e2) 
1# SPDX-License-Identifier: GPL-2.0-only
2#
3# Makefile for compat_vdso
4#
5
6# Symbols present in the compat_vdso
7compat_vdso-syms  = rt_sigreturn
8compat_vdso-syms += getcpu
9compat_vdso-syms += flush_icache
10
11COMPAT_CC := $(CC)
12COMPAT_LD := $(LD)
13
14# binutils 2.35 does not support the zifencei extension, but in the ISA
15# spec 20191213, G stands for IMAFD_ZICSR_ZIFENCEI.
16ifdef CONFIG_TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
17	COMPAT_CC_FLAGS := -march=rv32g -mabi=ilp32
18else
19	COMPAT_CC_FLAGS := -march=rv32imafd -mabi=ilp32
20endif
21COMPAT_LD_FLAGS := -melf32lriscv
22
23# Disable attributes, as they're useless and break the build.
24COMPAT_CC_FLAGS += $(call cc-option,-mno-riscv-attribute)
25COMPAT_CC_FLAGS += $(call as-option,-Wa$(comma)-mno-arch-attr)
26
27# Files to link into the compat_vdso
28obj-compat_vdso = $(patsubst %, %.o, $(compat_vdso-syms)) note.o
29
30# Build rules
31targets := $(obj-compat_vdso) compat_vdso.so compat_vdso.so.dbg compat_vdso.lds
32obj-compat_vdso := $(addprefix $(obj)/, $(obj-compat_vdso))
33
34obj-y += compat_vdso.o
35CPPFLAGS_compat_vdso.lds += -P -C -DCOMPAT_VDSO -U$(ARCH)
36
37# Force dependency
38$(obj)/compat_vdso.o: $(obj)/compat_vdso.so
39
40# link rule for the .so file, .lds has to be first
41$(obj)/compat_vdso.so.dbg: $(obj)/compat_vdso.lds $(obj-compat_vdso) FORCE
42	$(call if_changed,compat_vdsold)
43LDFLAGS_compat_vdso.so.dbg = -shared -S -soname=linux-compat_vdso.so.1 \
44	--build-id=sha1 --hash-style=both --eh-frame-hdr
45
46$(obj-compat_vdso): %.o: %.S FORCE
47	$(call if_changed_dep,compat_vdsoas)
48
49# strip rule for the .so file
50$(obj)/%.so: OBJCOPYFLAGS := -S
51$(obj)/%.so: $(obj)/%.so.dbg FORCE
52	$(call if_changed,objcopy)
53
54# Generate VDSO offsets using helper script
55gen-compat_vdsosym := $(src)/gen_compat_vdso_offsets.sh
56quiet_cmd_compat_vdsosym = VDSOSYM $@
57	cmd_compat_vdsosym = $(NM) $< | $(gen-compat_vdsosym) | LC_ALL=C sort > $@
58
59include/generated/compat_vdso-offsets.h: $(obj)/compat_vdso.so.dbg FORCE
60	$(call if_changed,compat_vdsosym)
61
62# actual build commands
63# The DSO images are built using a special linker script
64# Make sure only to export the intended __compat_vdso_xxx symbol offsets.
65quiet_cmd_compat_vdsold = VDSOLD  $@
66      cmd_compat_vdsold = $(COMPAT_LD) $(ld_flags) $(COMPAT_LD_FLAGS) -T $(filter-out FORCE,$^) -o $@.tmp && \
67                   $(OBJCOPY) $(patsubst %, -G __compat_vdso_%, $(compat_vdso-syms)) $@.tmp $@ && \
68                   rm $@.tmp
69
70# actual build commands
71quiet_cmd_compat_vdsoas = VDSOAS  $@
72      cmd_compat_vdsoas = $(COMPAT_CC) $(a_flags) $(COMPAT_CC_FLAGS) -c -o $@ $<
73