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