Makefile

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