1# SPDX-License-Identifier: GPL-2.0 2# 3# Building vDSO images for x86. 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_X86_64_JUMP_SLOT|R_X86_64_GLOB_DAT|R_X86_64_RELATIVE| 9ARCH_REL_TYPE_ABS += R_386_GLOB_DAT|R_386_JMP_SLOT|R_386_RELATIVE 10include $(srctree)/lib/vdso/Makefile 11 12KBUILD_CFLAGS += $(DISABLE_LTO) 13KASAN_SANITIZE := n 14UBSAN_SANITIZE := n 15OBJECT_FILES_NON_STANDARD := y 16 17# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in. 18KCOV_INSTRUMENT := n 19 20VDSO64-$(CONFIG_X86_64) := y 21VDSOX32-$(CONFIG_X86_X32_ABI) := y 22VDSO32-$(CONFIG_X86_32) := y 23VDSO32-$(CONFIG_IA32_EMULATION) := y 24 25# files to link into the vdso 26vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o 27 28# files to link into kernel 29obj-y += vma.o 30OBJECT_FILES_NON_STANDARD_vma.o := n 31 32# vDSO images to build 33vdso_img-$(VDSO64-y) += 64 34vdso_img-$(VDSOX32-y) += x32 35vdso_img-$(VDSO32-y) += 32 36 37obj-$(VDSO32-y) += vdso32-setup.o 38 39vobjs := $(foreach F,$(vobjs-y),$(obj)/$F) 40 41$(obj)/vdso.o: $(obj)/vdso.so 42 43targets += vdso.lds $(vobjs-y) 44 45# Build the vDSO image C files and link them in. 46vdso_img_objs := $(vdso_img-y:%=vdso-image-%.o) 47vdso_img_cfiles := $(vdso_img-y:%=vdso-image-%.c) 48vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg) 49obj-y += $(vdso_img_objs) 50targets += $(vdso_img_cfiles) 51targets += $(vdso_img_sodbg) $(vdso_img-y:%=vdso%.so) 52 53CPPFLAGS_vdso.lds += -P -C 54 55VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --no-undefined \ 56 -z max-page-size=4096 57 58$(obj)/vdso64.so.dbg: $(obj)/vdso.lds $(vobjs) FORCE 59 $(call if_changed,vdso_and_check) 60 61HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/$(SUBARCH)/include/uapi 62hostprogs-y += vdso2c 63 64quiet_cmd_vdso2c = VDSO2C $@ 65 cmd_vdso2c = $(obj)/vdso2c $< $(<:%.dbg=%) $@ 66 67$(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE 68 $(call if_changed,vdso2c) 69 70# 71# Don't omit frame pointers for ease of userspace debugging, but do 72# optimize sibling calls. 73# 74CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \ 75 $(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \ 76 -fno-omit-frame-pointer -foptimize-sibling-calls \ 77 -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO 78 79ifdef CONFIG_RETPOLINE 80ifneq ($(RETPOLINE_VDSO_CFLAGS),) 81 CFL += $(RETPOLINE_VDSO_CFLAGS) 82endif 83endif 84 85$(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL) 86 87# 88# vDSO code runs in userspace and -pg doesn't help with profiling anyway. 89# 90CFLAGS_REMOVE_vdso-note.o = -pg 91CFLAGS_REMOVE_vclock_gettime.o = -pg 92CFLAGS_REMOVE_vgetcpu.o = -pg 93CFLAGS_REMOVE_vvar.o = -pg 94 95# 96# X32 processes use x32 vDSO to access 64bit kernel data. 97# 98# Build x32 vDSO image: 99# 1. Compile x32 vDSO as 64bit. 100# 2. Convert object files to x32. 101# 3. Build x32 VDSO image with x32 objects, which contains 64bit codes 102# so that it can reach 64bit address space with 64bit pointers. 103# 104 105CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds) 106VDSO_LDFLAGS_vdsox32.lds = -m elf32_x86_64 -soname linux-vdso.so.1 \ 107 -z max-page-size=4096 108 109# x32-rebranded versions 110vobjx32s-y := $(vobjs-y:.o=-x32.o) 111 112# same thing, but in the output directory 113vobjx32s := $(foreach F,$(vobjx32s-y),$(obj)/$F) 114 115# Convert 64bit object file to x32 for x32 vDSO. 116quiet_cmd_x32 = X32 $@ 117 cmd_x32 = $(OBJCOPY) -O elf32-x86-64 $< $@ 118 119$(obj)/%-x32.o: $(obj)/%.o FORCE 120 $(call if_changed,x32) 121 122targets += vdsox32.lds $(vobjx32s-y) 123 124$(obj)/%.so: OBJCOPYFLAGS := -S 125$(obj)/%.so: $(obj)/%.so.dbg FORCE 126 $(call if_changed,objcopy) 127 128$(obj)/vdsox32.so.dbg: $(obj)/vdsox32.lds $(vobjx32s) FORCE 129 $(call if_changed,vdso_and_check) 130 131CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds) 132VDSO_LDFLAGS_vdso32.lds = -m elf_i386 -soname linux-gate.so.1 133 134targets += vdso32/vdso32.lds 135targets += vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o 136targets += vdso32/vclock_gettime.o 137 138KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS)) -DBUILD_VDSO 139$(obj)/vdso32.so.dbg: KBUILD_AFLAGS = $(KBUILD_AFLAGS_32) 140$(obj)/vdso32.so.dbg: asflags-$(CONFIG_X86_64) += -m32 141 142KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS)) 143KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32)) 144KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32)) 145KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32)) 146KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32)) 147KBUILD_CFLAGS_32 := $(filter-out $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS_32)) 148KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic 149KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector) 150KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls) 151KBUILD_CFLAGS_32 += -fno-omit-frame-pointer 152KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING 153 154ifdef CONFIG_RETPOLINE 155ifneq ($(RETPOLINE_VDSO_CFLAGS),) 156 KBUILD_CFLAGS_32 += $(RETPOLINE_VDSO_CFLAGS) 157endif 158endif 159 160$(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32) 161 162$(obj)/vdso32.so.dbg: FORCE \ 163 $(obj)/vdso32/vdso32.lds \ 164 $(obj)/vdso32/vclock_gettime.o \ 165 $(obj)/vdso32/note.o \ 166 $(obj)/vdso32/system_call.o \ 167 $(obj)/vdso32/sigreturn.o 168 $(call if_changed,vdso_and_check) 169 170# 171# The DSO images are built using a special linker script. 172# 173quiet_cmd_vdso = VDSO $@ 174 cmd_vdso = $(LD) -nostdlib -o $@ \ 175 $(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \ 176 -T $(filter %.lds,$^) $(filter %.o,$^) && \ 177 sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@' 178 179VDSO_LDFLAGS = -shared $(call ld-option, --hash-style=both) \ 180 $(call ld-option, --build-id) $(call ld-option, --eh-frame-hdr) \ 181 -Bsymbolic 182GCOV_PROFILE := n 183 184quiet_cmd_vdso_and_check = VDSO $@ 185 cmd_vdso_and_check = $(cmd_vdso); $(cmd_vdso_check) 186 187# 188# Install the unstripped copies of vdso*.so. If our toolchain supports 189# build-id, install .build-id links as well. 190# 191quiet_cmd_vdso_install = INSTALL $(@:install_%=%) 192define cmd_vdso_install 193 cp $< "$(MODLIB)/vdso/$(@:install_%=%)"; \ 194 if readelf -n $< |grep -q 'Build ID'; then \ 195 buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \ 196 first=`echo $$buildid | cut -b-2`; \ 197 last=`echo $$buildid | cut -b3-`; \ 198 mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \ 199 ln -sf "../../$(@:install_%=%)" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \ 200 fi 201endef 202 203vdso_img_insttargets := $(vdso_img_sodbg:%.dbg=install_%) 204 205$(MODLIB)/vdso: FORCE 206 @mkdir -p $(MODLIB)/vdso 207 208$(vdso_img_insttargets): install_%: $(obj)/%.dbg $(MODLIB)/vdso 209 $(call cmd,vdso_install) 210 211PHONY += vdso_install $(vdso_img_insttargets) 212vdso_install: $(vdso_img_insttargets) 213 214clean-files := vdso32.so vdso32.so.dbg vdso64* vdso-image-*.c vdsox32.so* 215