1# SPDX-License-Identifier: GPL-2.0 2# 3# Makefile for vdso32 4# 5 6# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before 7# the inclusion of generic Makefile. 8ARCH_REL_TYPE_ABS := R_ARM_JUMP_SLOT|R_ARM_GLOB_DAT|R_ARM_ABS32 9include $(srctree)/lib/vdso/Makefile 10 11# Same as cc-*option, but using CC_COMPAT instead of CC 12ifeq ($(CONFIG_CC_IS_CLANG), y) 13CC_COMPAT_CLANG_FLAGS := --target=$(notdir $(CROSS_COMPILE_COMPAT:%-=%)) 14 15CC_COMPAT ?= $(CC) 16CC_COMPAT += $(CC_COMPAT_CLANG_FLAGS) 17 18ifneq ($(LLVM),) 19LD_COMPAT ?= $(LD) 20else 21LD_COMPAT ?= $(CROSS_COMPILE_COMPAT)ld 22endif 23else 24CC_COMPAT ?= $(CROSS_COMPILE_COMPAT)gcc 25LD_COMPAT ?= $(CROSS_COMPILE_COMPAT)ld 26endif 27 28cc32-option = $(call try-run,\ 29 $(CC_COMPAT) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2)) 30cc32-disable-warning = $(call try-run,\ 31 $(CC_COMPAT) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1))) 32 33# We cannot use the global flags to compile the vDSO files, the main reason 34# being that the 32-bit compiler may be older than the main (64-bit) compiler 35# and therefore may not understand flags set using $(cc-option ...). Besides, 36# arch-specific options should be taken from the arm Makefile instead of the 37# arm64 one. 38# As a result we set our own flags here. 39 40# KBUILD_CPPFLAGS and NOSTDINC_FLAGS from top-level Makefile 41VDSO_CPPFLAGS := -DBUILD_VDSO -D__KERNEL__ -nostdinc -isystem $(shell $(CC_COMPAT) -print-file-name=include) 42VDSO_CPPFLAGS += $(LINUXINCLUDE) 43 44# Common C and assembly flags 45# From top-level Makefile 46VDSO_CAFLAGS := $(VDSO_CPPFLAGS) 47ifneq ($(shell $(CC_COMPAT) --version 2>&1 | head -n 1 | grep clang),) 48VDSO_CAFLAGS += --target=$(notdir $(CROSS_COMPILE_COMPAT:%-=%)) 49endif 50 51VDSO_CAFLAGS += $(call cc32-option,-fno-PIE) 52ifdef CONFIG_DEBUG_INFO 53VDSO_CAFLAGS += -g 54endif 55 56# From arm Makefile 57VDSO_CAFLAGS += $(call cc32-option,-fno-dwarf2-cfi-asm) 58VDSO_CAFLAGS += -mabi=aapcs-linux -mfloat-abi=soft 59ifeq ($(CONFIG_CPU_BIG_ENDIAN), y) 60VDSO_CAFLAGS += -mbig-endian 61else 62VDSO_CAFLAGS += -mlittle-endian 63endif 64 65# From arm vDSO Makefile 66VDSO_CAFLAGS += -fPIC -fno-builtin -fno-stack-protector 67VDSO_CAFLAGS += -DDISABLE_BRANCH_PROFILING 68 69 70# Try to compile for ARMv8. If the compiler is too old and doesn't support it, 71# fall back to v7. There is no easy way to check for what architecture the code 72# is being compiled, so define a macro specifying that (see arch/arm/Makefile). 73VDSO_CAFLAGS += $(call cc32-option,-march=armv8-a -D__LINUX_ARM_ARCH__=8,\ 74 -march=armv7-a -D__LINUX_ARM_ARCH__=7) 75 76VDSO_CFLAGS := $(VDSO_CAFLAGS) 77VDSO_CFLAGS += -DENABLE_COMPAT_VDSO=1 78# KBUILD_CFLAGS from top-level Makefile 79VDSO_CFLAGS += -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \ 80 -fno-strict-aliasing -fno-common \ 81 -Werror-implicit-function-declaration \ 82 -Wno-format-security \ 83 -std=gnu89 84VDSO_CFLAGS += -O2 85# Some useful compiler-dependent flags from top-level Makefile 86VDSO_CFLAGS += $(call cc32-option,-Wdeclaration-after-statement,) 87VDSO_CFLAGS += $(call cc32-option,-Wno-pointer-sign) 88VDSO_CFLAGS += -fno-strict-overflow 89VDSO_CFLAGS += $(call cc32-option,-Werror=strict-prototypes) 90VDSO_CFLAGS += -Werror=date-time 91VDSO_CFLAGS += $(call cc32-option,-Werror=incompatible-pointer-types) 92 93# The 32-bit compiler does not provide 128-bit integers, which are used in 94# some headers that are indirectly included from the vDSO code. 95# This hack makes the compiler happy and should trigger a warning/error if 96# variables of such type are referenced. 97VDSO_CFLAGS += -D__uint128_t='void*' 98# Silence some warnings coming from headers that operate on long's 99# (on GCC 4.8 or older, there is unfortunately no way to silence this warning) 100VDSO_CFLAGS += $(call cc32-disable-warning,shift-count-overflow) 101VDSO_CFLAGS += -Wno-int-to-pointer-cast 102 103# Compile as THUMB2 or ARM. Unwinding via frame-pointers in THUMB2 is 104# unreliable. 105ifeq ($(CONFIG_THUMB2_COMPAT_VDSO), y) 106VDSO_CFLAGS += -mthumb -fomit-frame-pointer 107else 108VDSO_CFLAGS += -marm 109endif 110 111VDSO_AFLAGS := $(VDSO_CAFLAGS) 112VDSO_AFLAGS += -D__ASSEMBLY__ 113 114# From arm vDSO Makefile 115VDSO_LDFLAGS += -Bsymbolic --no-undefined -soname=linux-vdso.so.1 116VDSO_LDFLAGS += -z max-page-size=4096 -z common-page-size=4096 117VDSO_LDFLAGS += -nostdlib -shared --hash-style=sysv --build-id=sha1 118 119 120# Borrow vdsomunge.c from the arm vDSO 121# We have to use a relative path because scripts/Makefile.host prefixes 122# $(hostprogs) with $(obj) 123munge := ../../../arm/vdso/vdsomunge 124hostprogs := $(munge) 125 126c-obj-vdso := note.o 127c-obj-vdso-gettimeofday := vgettimeofday.o 128 129ifneq ($(c-gettimeofday-y),) 130VDSO_CFLAGS_gettimeofday_o += -include $(c-gettimeofday-y) 131endif 132 133VDSO_CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os 134 135# Build rules 136targets := $(c-obj-vdso) $(c-obj-vdso-gettimeofday) $(asm-obj-vdso) vdso.so vdso.so.dbg vdso.so.raw 137c-obj-vdso := $(addprefix $(obj)/, $(c-obj-vdso)) 138c-obj-vdso-gettimeofday := $(addprefix $(obj)/, $(c-obj-vdso-gettimeofday)) 139asm-obj-vdso := $(addprefix $(obj)/, $(asm-obj-vdso)) 140obj-vdso := $(c-obj-vdso) $(c-obj-vdso-gettimeofday) $(asm-obj-vdso) 141 142targets += vdso.lds 143CPPFLAGS_vdso.lds += -P -C -U$(ARCH) 144 145# Force dependency (vdso.s includes vdso.so through incbin) 146$(obj)/vdso.o: $(obj)/vdso.so 147 148include/generated/vdso32-offsets.h: $(obj)/vdso.so.dbg FORCE 149 $(call if_changed,vdsosym) 150 151# Strip rule for vdso.so 152$(obj)/vdso.so: OBJCOPYFLAGS := -S 153$(obj)/vdso.so: $(obj)/vdso.so.dbg FORCE 154 $(call if_changed,objcopy) 155 156$(obj)/vdso.so.dbg: $(obj)/vdso.so.raw $(obj)/$(munge) FORCE 157 $(call if_changed,vdsomunge) 158 159# Link rule for the .so file, .lds has to be first 160$(obj)/vdso.so.raw: $(src)/vdso.lds $(obj-vdso) FORCE 161 $(call if_changed,vdsold_and_vdso_check) 162 163# Compilation rules for the vDSO sources 164$(c-obj-vdso): %.o: %.c FORCE 165 $(call if_changed_dep,vdsocc) 166$(c-obj-vdso-gettimeofday): %.o: %.c FORCE 167 $(call if_changed_dep,vdsocc_gettimeofday) 168$(asm-obj-vdso): %.o: %.S FORCE 169 $(call if_changed_dep,vdsoas) 170 171# Actual build commands 172quiet_cmd_vdsold_and_vdso_check = LD32 $@ 173 cmd_vdsold_and_vdso_check = $(cmd_vdsold); $(cmd_vdso_check) 174 175quiet_cmd_vdsold = LD32 $@ 176 cmd_vdsold = $(LD_COMPAT) $(VDSO_LDFLAGS) \ 177 -T $(filter %.lds,$^) $(filter %.o,$^) -o $@ 178quiet_cmd_vdsocc = CC32 $@ 179 cmd_vdsocc = $(CC_COMPAT) -Wp,-MD,$(depfile) $(VDSO_CFLAGS) -c -o $@ $< 180quiet_cmd_vdsocc_gettimeofday = CC32 $@ 181 cmd_vdsocc_gettimeofday = $(CC_COMPAT) -Wp,-MD,$(depfile) $(VDSO_CFLAGS) $(VDSO_CFLAGS_gettimeofday_o) -c -o $@ $< 182quiet_cmd_vdsoas = AS32 $@ 183 cmd_vdsoas = $(CC_COMPAT) -Wp,-MD,$(depfile) $(VDSO_AFLAGS) -c -o $@ $< 184 185quiet_cmd_vdsomunge = MUNGE $@ 186 cmd_vdsomunge = $(obj)/$(munge) $< $@ 187 188# Generate vDSO offsets using helper script (borrowed from the 64-bit vDSO) 189gen-vdsosym := $(srctree)/$(src)/../vdso/gen_vdso_offsets.sh 190quiet_cmd_vdsosym = VDSOSYM $@ 191# The AArch64 nm should be able to read an AArch32 binary 192 cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@ 193 194# Install commands for the unstripped file 195quiet_cmd_vdso_install = INSTALL32 $@ 196 cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/vdso32.so 197 198vdso.so: $(obj)/vdso.so.dbg 199 @mkdir -p $(MODLIB)/vdso 200 $(call cmd,vdso_install) 201 202vdso_install: vdso.so 203