1 # SPDX-License-Identifier: GPL-2.0
2 #
3 # Building a vDSO image for AArch64.
4 #
5 # Author: Will Deacon <will.deacon@arm.com>
6 # Heavily based on the vDSO Makefiles for other archs.
7 #
8
9 # Include the generic Makefile to check the built vdso.
10 include $(srctree)/lib/vdso/Makefile
11
12 obj-vdso := vgettimeofday.o note.o sigreturn.o vgetrandom.o vgetrandom-chacha.o
13
14 # Build rules
15 targets := $(obj-vdso) vdso.so vdso.so.dbg
16 obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
17
18 btildflags-$(CONFIG_ARM64_BTI_KERNEL) += -z force-bti
19
20 # -Bsymbolic has been added for consistency with arm, the compat vDSO and
21 # potential future proofing if we end up with internal calls to the exported
22 # routines, as x86 does (see 6f121e548f83 ("x86, vdso: Reimplement vdso.so
23 # preparation in build-time C")).
24 ldflags-y := -shared -soname=linux-vdso.so.1 \
25 -Bsymbolic --build-id=sha1 -n $(btildflags-y)
26
27 ifdef CONFIG_LD_ORPHAN_WARN
28 ldflags-y += --orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL)
29 endif
30
31 ldflags-y += -T
32
33 ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18
34 ccflags-y += -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
35
36 # -Wmissing-prototypes and -Wmissing-declarations are removed from
37 # the CFLAGS to make possible to build the kernel with CONFIG_WERROR enabled.
38 CC_FLAGS_REMOVE_VDSO := $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) \
39 $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) \
40 $(CC_FLAGS_LTO) $(CC_FLAGS_CFI) \
41 -Wmissing-prototypes -Wmissing-declarations
42
43 CC_FLAGS_ADD_VDSO := -O2 -mcmodel=tiny -fasynchronous-unwind-tables
44
45 CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_REMOVE_VDSO)
46 CFLAGS_REMOVE_vgetrandom.o = $(CC_FLAGS_REMOVE_VDSO)
47
48 CFLAGS_vgettimeofday.o = $(CC_FLAGS_ADD_VDSO)
49 CFLAGS_vgetrandom.o = $(CC_FLAGS_ADD_VDSO)
50
51 ifneq ($(c-gettimeofday-y),)
52 CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
53 endif
54
55 ifneq ($(c-getrandom-y),)
56 CFLAGS_vgetrandom.o += -include $(c-getrandom-y)
57 endif
58
59 targets += vdso.lds
60 CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
61
62 # Link rule for the .so file, .lds has to be first
63 $(obj)/vdso.so.dbg: $(obj)/vdso.lds $(obj-vdso) FORCE
64 $(call if_changed,vdsold_and_vdso_check)
65
66 # Strip rule for the .so file
67 $(obj)/%.so: OBJCOPYFLAGS := -S
68 $(obj)/%.so: $(obj)/%.so.dbg FORCE
69 $(call if_changed,objcopy)
70
71 # Generate VDSO offsets using helper script
72 gen-vdsosym := $(src)/gen_vdso_offsets.sh
73 quiet_cmd_vdsosym = VDSOSYM $@
74 cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
75
76 include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE
77 $(call if_changed,vdsosym)
78
79 # Actual build commands
80 quiet_cmd_vdsold_and_vdso_check = LD $@
81 cmd_vdsold_and_vdso_check = $(cmd_ld); $(cmd_vdso_check)
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