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) 13COMPAT_GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE_COMPAT)elfedit)) 14COMPAT_GCC_TOOLCHAIN := $(realpath $(COMPAT_GCC_TOOLCHAIN_DIR)/..) 15 16CC_COMPAT_CLANG_FLAGS := --target=$(notdir $(CROSS_COMPILE_COMPAT:%-=%)) 17CC_COMPAT_CLANG_FLAGS += --prefix=$(COMPAT_GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE_COMPAT)) 18CC_COMPAT_CLANG_FLAGS += -no-integrated-as -Qunused-arguments 19ifneq ($(COMPAT_GCC_TOOLCHAIN),) 20CC_COMPAT_CLANG_FLAGS += --gcc-toolchain=$(COMPAT_GCC_TOOLCHAIN) 21endif 22 23CC_COMPAT ?= $(CC) 24CC_COMPAT += $(CC_COMPAT_CLANG_FLAGS) 25 26ifneq ($(LLVM),) 27LD_COMPAT ?= $(LD) 28else 29LD_COMPAT ?= $(CROSS_COMPILE_COMPAT)ld 30endif 31else 32CC_COMPAT ?= $(CROSS_COMPILE_COMPAT)gcc 33LD_COMPAT ?= $(CROSS_COMPILE_COMPAT)ld 34endif 35 36cc32-option = $(call try-run,\ 37 $(CC_COMPAT) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2)) 38cc32-disable-warning = $(call try-run,\ 39 $(CC_COMPAT) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1))) 40cc32-as-instr = $(call try-run,\ 41 printf "%b\n" "$(1)" | $(CC_COMPAT) $(VDSO_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3)) 42 43# We cannot use the global flags to compile the vDSO files, the main reason 44# being that the 32-bit compiler may be older than the main (64-bit) compiler 45# and therefore may not understand flags set using $(cc-option ...). Besides, 46# arch-specific options should be taken from the arm Makefile instead of the 47# arm64 one. 48# As a result we set our own flags here. 49 50# KBUILD_CPPFLAGS and NOSTDINC_FLAGS from top-level Makefile 51VDSO_CPPFLAGS := -DBUILD_VDSO -D__KERNEL__ -nostdinc -isystem $(shell $(CC_COMPAT) -print-file-name=include) 52VDSO_CPPFLAGS += $(LINUXINCLUDE) 53 54# Common C and assembly flags 55# From top-level Makefile 56VDSO_CAFLAGS := $(VDSO_CPPFLAGS) 57ifneq ($(shell $(CC_COMPAT) --version 2>&1 | head -n 1 | grep clang),) 58VDSO_CAFLAGS += --target=$(notdir $(CROSS_COMPILE_COMPAT:%-=%)) 59endif 60 61VDSO_CAFLAGS += $(call cc32-option,-fno-PIE) 62ifdef CONFIG_DEBUG_INFO 63VDSO_CAFLAGS += -g 64endif 65 66# From arm Makefile 67VDSO_CAFLAGS += $(call cc32-option,-fno-dwarf2-cfi-asm) 68VDSO_CAFLAGS += -mabi=aapcs-linux -mfloat-abi=soft 69ifeq ($(CONFIG_CPU_BIG_ENDIAN), y) 70VDSO_CAFLAGS += -mbig-endian 71else 72VDSO_CAFLAGS += -mlittle-endian 73endif 74 75# From arm vDSO Makefile 76VDSO_CAFLAGS += -fPIC -fno-builtin -fno-stack-protector 77VDSO_CAFLAGS += -DDISABLE_BRANCH_PROFILING 78 79 80# Try to compile for ARMv8. If the compiler is too old and doesn't support it, 81# fall back to v7. There is no easy way to check for what architecture the code 82# is being compiled, so define a macro specifying that (see arch/arm/Makefile). 83VDSO_CAFLAGS += $(call cc32-option,-march=armv8-a -D__LINUX_ARM_ARCH__=8,\ 84 -march=armv7-a -D__LINUX_ARM_ARCH__=7) 85 86VDSO_CFLAGS := $(VDSO_CAFLAGS) 87VDSO_CFLAGS += -DENABLE_COMPAT_VDSO=1 88# KBUILD_CFLAGS from top-level Makefile 89VDSO_CFLAGS += -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \ 90 -fno-strict-aliasing -fno-common \ 91 -Werror-implicit-function-declaration \ 92 -Wno-format-security \ 93 -std=gnu89 94VDSO_CFLAGS += -O2 95# Some useful compiler-dependent flags from top-level Makefile 96VDSO_CFLAGS += $(call cc32-option,-Wdeclaration-after-statement,) 97VDSO_CFLAGS += $(call cc32-option,-Wno-pointer-sign) 98VDSO_CFLAGS += -fno-strict-overflow 99VDSO_CFLAGS += $(call cc32-option,-Werror=strict-prototypes) 100VDSO_CFLAGS += -Werror=date-time 101VDSO_CFLAGS += $(call cc32-option,-Werror=incompatible-pointer-types) 102 103# The 32-bit compiler does not provide 128-bit integers, which are used in 104# some headers that are indirectly included from the vDSO code. 105# This hack makes the compiler happy and should trigger a warning/error if 106# variables of such type are referenced. 107VDSO_CFLAGS += -D__uint128_t='void*' 108# Silence some warnings coming from headers that operate on long's 109# (on GCC 4.8 or older, there is unfortunately no way to silence this warning) 110VDSO_CFLAGS += $(call cc32-disable-warning,shift-count-overflow) 111VDSO_CFLAGS += -Wno-int-to-pointer-cast 112 113# Compile as THUMB2 or ARM. Unwinding via frame-pointers in THUMB2 is 114# unreliable. 115ifeq ($(CONFIG_THUMB2_COMPAT_VDSO), y) 116VDSO_CFLAGS += -mthumb -fomit-frame-pointer 117else 118VDSO_CFLAGS += -marm 119endif 120 121VDSO_AFLAGS := $(VDSO_CAFLAGS) 122VDSO_AFLAGS += -D__ASSEMBLY__ 123 124# Check for binutils support for dmb ishld 125dmbinstr := $(call cc32-as-instr,dmb ishld,-DCONFIG_AS_DMB_ISHLD=1) 126 127VDSO_CFLAGS += $(dmbinstr) 128VDSO_AFLAGS += $(dmbinstr) 129 130# From arm vDSO Makefile 131VDSO_LDFLAGS += -Bsymbolic --no-undefined -soname=linux-vdso.so.1 132VDSO_LDFLAGS += -z max-page-size=4096 -z common-page-size=4096 133VDSO_LDFLAGS += -nostdlib -shared --hash-style=sysv --build-id=sha1 134 135 136# Borrow vdsomunge.c from the arm vDSO 137# We have to use a relative path because scripts/Makefile.host prefixes 138# $(hostprogs) with $(obj) 139munge := ../../../arm/vdso/vdsomunge 140hostprogs := $(munge) 141 142c-obj-vdso := note.o 143c-obj-vdso-gettimeofday := vgettimeofday.o 144 145ifneq ($(c-gettimeofday-y),) 146VDSO_CFLAGS_gettimeofday_o += -include $(c-gettimeofday-y) 147endif 148 149VDSO_CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os 150 151# Build rules 152targets := $(c-obj-vdso) $(c-obj-vdso-gettimeofday) $(asm-obj-vdso) vdso.so vdso.so.dbg vdso.so.raw 153c-obj-vdso := $(addprefix $(obj)/, $(c-obj-vdso)) 154c-obj-vdso-gettimeofday := $(addprefix $(obj)/, $(c-obj-vdso-gettimeofday)) 155asm-obj-vdso := $(addprefix $(obj)/, $(asm-obj-vdso)) 156obj-vdso := $(c-obj-vdso) $(c-obj-vdso-gettimeofday) $(asm-obj-vdso) 157 158obj-y += vdso.o 159targets += vdso.lds 160CPPFLAGS_vdso.lds += -P -C -U$(ARCH) 161 162# Force dependency (vdso.s includes vdso.so through incbin) 163$(obj)/vdso.o: $(obj)/vdso.so 164 165include/generated/vdso32-offsets.h: $(obj)/vdso.so.dbg FORCE 166 $(call if_changed,vdsosym) 167 168# Strip rule for vdso.so 169$(obj)/vdso.so: OBJCOPYFLAGS := -S 170$(obj)/vdso.so: $(obj)/vdso.so.dbg FORCE 171 $(call if_changed,objcopy) 172 173$(obj)/vdso.so.dbg: $(obj)/vdso.so.raw $(obj)/$(munge) FORCE 174 $(call if_changed,vdsomunge) 175 176# Link rule for the .so file, .lds has to be first 177$(obj)/vdso.so.raw: $(src)/vdso.lds $(obj-vdso) FORCE 178 $(call if_changed,vdsold_and_vdso_check) 179 180# Compilation rules for the vDSO sources 181$(c-obj-vdso): %.o: %.c FORCE 182 $(call if_changed_dep,vdsocc) 183$(c-obj-vdso-gettimeofday): %.o: %.c FORCE 184 $(call if_changed_dep,vdsocc_gettimeofday) 185$(asm-obj-vdso): %.o: %.S FORCE 186 $(call if_changed_dep,vdsoas) 187 188# Actual build commands 189quiet_cmd_vdsold_and_vdso_check = LD32 $@ 190 cmd_vdsold_and_vdso_check = $(cmd_vdsold); $(cmd_vdso_check) 191 192quiet_cmd_vdsold = LD32 $@ 193 cmd_vdsold = $(LD_COMPAT) $(VDSO_LDFLAGS) \ 194 -T $(filter %.lds,$^) $(filter %.o,$^) -o $@ 195quiet_cmd_vdsocc = CC32 $@ 196 cmd_vdsocc = $(CC_COMPAT) -Wp,-MD,$(depfile) $(VDSO_CFLAGS) -c -o $@ $< 197quiet_cmd_vdsocc_gettimeofday = CC32 $@ 198 cmd_vdsocc_gettimeofday = $(CC_COMPAT) -Wp,-MD,$(depfile) $(VDSO_CFLAGS) $(VDSO_CFLAGS_gettimeofday_o) -c -o $@ $< 199quiet_cmd_vdsoas = AS32 $@ 200 cmd_vdsoas = $(CC_COMPAT) -Wp,-MD,$(depfile) $(VDSO_AFLAGS) -c -o $@ $< 201 202quiet_cmd_vdsomunge = MUNGE $@ 203 cmd_vdsomunge = $(obj)/$(munge) $< $@ 204 205# Generate vDSO offsets using helper script (borrowed from the 64-bit vDSO) 206gen-vdsosym := $(srctree)/$(src)/../vdso/gen_vdso_offsets.sh 207quiet_cmd_vdsosym = VDSOSYM $@ 208# The AArch64 nm should be able to read an AArch32 binary 209 cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@ 210 211# Install commands for the unstripped file 212quiet_cmd_vdso_install = INSTALL32 $@ 213 cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/vdso32.so 214 215vdso.so: $(obj)/vdso.so.dbg 216 @mkdir -p $(MODLIB)/vdso 217 $(call cmd,vdso_install) 218 219vdso_install: vdso.so 220