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