1# SPDX-License-Identifier: GPL-2.0
2#
3# Makefile for vdso32
4#
5
6include $(srctree)/lib/vdso/Makefile
7
8# Same as cc-*option, but using CC_COMPAT instead of CC
9ifeq ($(CONFIG_CC_IS_CLANG), y)
10CC_COMPAT ?= $(CC)
11CC_COMPAT += --target=arm-linux-gnueabi
12else
13CC_COMPAT ?= $(CROSS_COMPILE_COMPAT)gcc
14endif
15
16ifeq ($(CONFIG_LD_IS_LLD), y)
17LD_COMPAT ?= $(LD)
18else
19LD_COMPAT ?= $(CROSS_COMPILE_COMPAT)ld
20endif
21
22cc32-option = $(call try-run,\
23        $(CC_COMPAT) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2))
24cc32-disable-warning = $(call try-run,\
25	$(CC_COMPAT) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
26
27# We cannot use the global flags to compile the vDSO files, the main reason
28# being that the 32-bit compiler may be older than the main (64-bit) compiler
29# and therefore may not understand flags set using $(cc-option ...). Besides,
30# arch-specific options should be taken from the arm Makefile instead of the
31# arm64 one.
32# As a result we set our own flags here.
33
34# KBUILD_CPPFLAGS and NOSTDINC_FLAGS from top-level Makefile
35VDSO_CPPFLAGS := -DBUILD_VDSO -D__KERNEL__ -nostdinc
36VDSO_CPPFLAGS += -isystem $(shell $(CC_COMPAT) -print-file-name=include 2>/dev/null)
37VDSO_CPPFLAGS += $(LINUXINCLUDE)
38
39# Common C and assembly flags
40# From top-level Makefile
41VDSO_CAFLAGS := $(VDSO_CPPFLAGS)
42VDSO_CAFLAGS += $(call cc32-option,-fno-PIE)
43ifdef CONFIG_DEBUG_INFO
44VDSO_CAFLAGS += -g
45endif
46
47# From arm Makefile
48VDSO_CAFLAGS += $(call cc32-option,-fno-dwarf2-cfi-asm)
49VDSO_CAFLAGS += -mabi=aapcs-linux -mfloat-abi=soft
50ifeq ($(CONFIG_CPU_BIG_ENDIAN), y)
51VDSO_CAFLAGS += -mbig-endian
52else
53VDSO_CAFLAGS += -mlittle-endian
54endif
55
56# From arm vDSO Makefile
57VDSO_CAFLAGS += -fPIC -fno-builtin -fno-stack-protector
58VDSO_CAFLAGS += -DDISABLE_BRANCH_PROFILING
59VDSO_CAFLAGS += -march=armv8-a
60
61VDSO_CFLAGS := $(VDSO_CAFLAGS)
62VDSO_CFLAGS += -DENABLE_COMPAT_VDSO=1
63# KBUILD_CFLAGS from top-level Makefile
64VDSO_CFLAGS += -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
65               -fno-strict-aliasing -fno-common \
66               -Werror-implicit-function-declaration \
67               -Wno-format-security \
68               -std=gnu11
69VDSO_CFLAGS  += -O2
70# Some useful compiler-dependent flags from top-level Makefile
71VDSO_CFLAGS += $(call cc32-option,-Wno-pointer-sign)
72VDSO_CFLAGS += -fno-strict-overflow
73VDSO_CFLAGS += $(call cc32-option,-Werror=strict-prototypes)
74VDSO_CFLAGS += -Werror=date-time
75VDSO_CFLAGS += $(call cc32-option,-Werror=incompatible-pointer-types)
76
77# The 32-bit compiler does not provide 128-bit integers, which are used in
78# some headers that are indirectly included from the vDSO code.
79# This hack makes the compiler happy and should trigger a warning/error if
80# variables of such type are referenced.
81VDSO_CFLAGS += -D__uint128_t='void*'
82# Silence some warnings coming from headers that operate on long's
83# (on GCC 4.8 or older, there is unfortunately no way to silence this warning)
84VDSO_CFLAGS += $(call cc32-disable-warning,shift-count-overflow)
85VDSO_CFLAGS += -Wno-int-to-pointer-cast
86
87# Compile as THUMB2 or ARM. Unwinding via frame-pointers in THUMB2 is
88# unreliable.
89ifeq ($(CONFIG_THUMB2_COMPAT_VDSO), y)
90VDSO_CFLAGS += -mthumb -fomit-frame-pointer
91else
92VDSO_CFLAGS += -marm
93endif
94
95VDSO_AFLAGS := $(VDSO_CAFLAGS)
96VDSO_AFLAGS += -D__ASSEMBLY__
97
98# From arm vDSO Makefile
99VDSO_LDFLAGS += -Bsymbolic --no-undefined -soname=linux-vdso.so.1
100VDSO_LDFLAGS += -z max-page-size=4096 -z common-page-size=4096
101VDSO_LDFLAGS += -shared --hash-style=sysv --build-id=sha1
102VDSO_LDFLAGS += --orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL)
103
104
105# Borrow vdsomunge.c from the arm vDSO
106# We have to use a relative path because scripts/Makefile.host prefixes
107# $(hostprogs) with $(obj)
108munge := ../../../arm/vdso/vdsomunge
109hostprogs := $(munge)
110
111c-obj-vdso := note.o
112c-obj-vdso-gettimeofday := vgettimeofday.o
113
114ifneq ($(c-gettimeofday-y),)
115VDSO_CFLAGS_gettimeofday_o += -include $(c-gettimeofday-y)
116endif
117
118VDSO_CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os
119
120# Build rules
121targets := $(c-obj-vdso) $(c-obj-vdso-gettimeofday) $(asm-obj-vdso) vdso.so vdso32.so.dbg vdso.so.raw
122c-obj-vdso := $(addprefix $(obj)/, $(c-obj-vdso))
123c-obj-vdso-gettimeofday := $(addprefix $(obj)/, $(c-obj-vdso-gettimeofday))
124asm-obj-vdso := $(addprefix $(obj)/, $(asm-obj-vdso))
125obj-vdso := $(c-obj-vdso) $(c-obj-vdso-gettimeofday) $(asm-obj-vdso)
126
127targets += vdso.lds
128CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
129
130# Strip rule for vdso.so
131$(obj)/vdso.so: OBJCOPYFLAGS := -S
132$(obj)/vdso.so: $(obj)/vdso32.so.dbg FORCE
133	$(call if_changed,objcopy)
134
135$(obj)/vdso32.so.dbg: $(obj)/vdso.so.raw $(obj)/$(munge) FORCE
136	$(call if_changed,vdsomunge)
137
138# Link rule for the .so file, .lds has to be first
139$(obj)/vdso.so.raw: $(src)/vdso.lds $(obj-vdso) FORCE
140	$(call if_changed,vdsold_and_vdso_check)
141
142# Compilation rules for the vDSO sources
143$(c-obj-vdso): %.o: %.c FORCE
144	$(call if_changed_dep,vdsocc)
145$(c-obj-vdso-gettimeofday): %.o: %.c FORCE
146	$(call if_changed_dep,vdsocc_gettimeofday)
147$(asm-obj-vdso): %.o: %.S FORCE
148	$(call if_changed_dep,vdsoas)
149
150# Actual build commands
151quiet_cmd_vdsold_and_vdso_check = LD32    $@
152      cmd_vdsold_and_vdso_check = $(cmd_vdsold); $(cmd_vdso_check)
153
154quiet_cmd_vdsold = LD32    $@
155      cmd_vdsold = $(LD_COMPAT) $(VDSO_LDFLAGS) \
156                   -T $(filter %.lds,$^) $(filter %.o,$^) -o $@
157quiet_cmd_vdsocc = CC32    $@
158      cmd_vdsocc = $(CC_COMPAT) -Wp,-MD,$(depfile) $(VDSO_CFLAGS) -c -o $@ $<
159quiet_cmd_vdsocc_gettimeofday = CC32    $@
160      cmd_vdsocc_gettimeofday = $(CC_COMPAT) -Wp,-MD,$(depfile) $(VDSO_CFLAGS) $(VDSO_CFLAGS_gettimeofday_o) -c -o $@ $<
161quiet_cmd_vdsoas = AS32    $@
162      cmd_vdsoas = $(CC_COMPAT) -Wp,-MD,$(depfile) $(VDSO_AFLAGS) -c -o $@ $<
163
164quiet_cmd_vdsomunge = MUNGE   $@
165      cmd_vdsomunge = $(obj)/$(munge) $< $@
166