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