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 += $(DISABLE_LTO) 13 14# Sanitizer runtimes are unavailable and cannot be linked here. 15KASAN_SANITIZE := n 16UBSAN_SANITIZE := n 17KCSAN_SANITIZE := n 18OBJECT_FILES_NON_STANDARD := y 19 20# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in. 21KCOV_INSTRUMENT := n 22 23VDSO64-$(CONFIG_X86_64) := y 24VDSOX32-$(CONFIG_X86_X32_ABI) := y 25VDSO32-$(CONFIG_X86_32) := y 26VDSO32-$(CONFIG_IA32_EMULATION) := y 27 28# files to link into the vdso 29vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o 30vobjs32-y := vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o 31vobjs32-y += vdso32/vclock_gettime.o 32 33# files to link into kernel 34obj-y += vma.o 35KASAN_SANITIZE_vma.o := y 36UBSAN_SANITIZE_vma.o := y 37KCSAN_SANITIZE_vma.o := y 38OBJECT_FILES_NON_STANDARD_vma.o := n 39 40# vDSO images to build 41vdso_img-$(VDSO64-y) += 64 42vdso_img-$(VDSOX32-y) += x32 43vdso_img-$(VDSO32-y) += 32 44 45obj-$(VDSO32-y) += vdso32-setup.o 46 47vobjs := $(foreach F,$(vobjs-y),$(obj)/$F) 48vobjs32 := $(foreach F,$(vobjs32-y),$(obj)/$F) 49 50$(obj)/vdso.o: $(obj)/vdso.so 51 52targets += vdso.lds $(vobjs-y) 53targets += vdso32/vdso32.lds $(vobjs32-y) 54 55# Build the vDSO image C files and link them in. 56vdso_img_objs := $(vdso_img-y:%=vdso-image-%.o) 57vdso_img_cfiles := $(vdso_img-y:%=vdso-image-%.c) 58vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg) 59obj-y += $(vdso_img_objs) 60targets += $(vdso_img_cfiles) 61targets += $(vdso_img_sodbg) $(vdso_img-y:%=vdso%.so) 62 63CPPFLAGS_vdso.lds += -P -C 64 65VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --no-undefined \ 66 -z max-page-size=4096 67 68$(obj)/vdso64.so.dbg: $(obj)/vdso.lds $(vobjs) FORCE 69 $(call if_changed,vdso_and_check) 70 71HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/$(SUBARCH)/include/uapi 72hostprogs += vdso2c 73 74quiet_cmd_vdso2c = VDSO2C $@ 75 cmd_vdso2c = $(obj)/vdso2c $< $(<:%.dbg=%) $@ 76 77$(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE 78 $(call if_changed,vdso2c) 79 80# 81# Don't omit frame pointers for ease of userspace debugging, but do 82# optimize sibling calls. 83# 84CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \ 85 $(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \ 86 -fno-omit-frame-pointer -foptimize-sibling-calls \ 87 -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO 88 89ifdef CONFIG_RETPOLINE 90ifneq ($(RETPOLINE_VDSO_CFLAGS),) 91 CFL += $(RETPOLINE_VDSO_CFLAGS) 92endif 93endif 94 95$(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL) 96 97# 98# vDSO code runs in userspace and -pg doesn't help with profiling anyway. 99# 100CFLAGS_REMOVE_vclock_gettime.o = -pg 101CFLAGS_REMOVE_vdso32/vclock_gettime.o = -pg 102CFLAGS_REMOVE_vgetcpu.o = -pg 103 104# 105# X32 processes use x32 vDSO to access 64bit kernel data. 106# 107# Build x32 vDSO image: 108# 1. Compile x32 vDSO as 64bit. 109# 2. Convert object files to x32. 110# 3. Build x32 VDSO image with x32 objects, which contains 64bit codes 111# so that it can reach 64bit address space with 64bit pointers. 112# 113 114CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds) 115VDSO_LDFLAGS_vdsox32.lds = -m elf32_x86_64 -soname linux-vdso.so.1 \ 116 -z max-page-size=4096 117 118# x32-rebranded versions 119vobjx32s-y := $(vobjs-y:.o=-x32.o) 120 121# same thing, but in the output directory 122vobjx32s := $(foreach F,$(vobjx32s-y),$(obj)/$F) 123 124# Convert 64bit object file to x32 for x32 vDSO. 125quiet_cmd_x32 = X32 $@ 126 cmd_x32 = $(OBJCOPY) -O elf32-x86-64 $< $@ 127 128$(obj)/%-x32.o: $(obj)/%.o FORCE 129 $(call if_changed,x32) 130 131targets += vdsox32.lds $(vobjx32s-y) 132 133$(obj)/%.so: OBJCOPYFLAGS := -S 134$(obj)/%.so: $(obj)/%.so.dbg FORCE 135 $(call if_changed,objcopy) 136 137$(obj)/vdsox32.so.dbg: $(obj)/vdsox32.lds $(vobjx32s) FORCE 138 $(call if_changed,vdso_and_check) 139 140CPPFLAGS_vdso32/vdso32.lds = $(CPPFLAGS_vdso.lds) 141VDSO_LDFLAGS_vdso32.lds = -m elf_i386 -soname linux-gate.so.1 142 143KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS)) -DBUILD_VDSO 144$(obj)/vdso32.so.dbg: KBUILD_AFLAGS = $(KBUILD_AFLAGS_32) 145$(obj)/vdso32.so.dbg: asflags-$(CONFIG_X86_64) += -m32 146 147KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS)) 148KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32)) 149KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32)) 150KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32)) 151KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32)) 152KBUILD_CFLAGS_32 := $(filter-out $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS_32)) 153KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic 154KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector) 155KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls) 156KBUILD_CFLAGS_32 += -fno-omit-frame-pointer 157KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING 158 159ifdef CONFIG_RETPOLINE 160ifneq ($(RETPOLINE_VDSO_CFLAGS),) 161 KBUILD_CFLAGS_32 += $(RETPOLINE_VDSO_CFLAGS) 162endif 163endif 164 165$(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32) 166 167$(obj)/vdso32.so.dbg: $(obj)/vdso32/vdso32.lds $(vobjs32) FORCE 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 --hash-style=both --build-id \ 180 $(call ld-option, --eh-frame-hdr) -Bsymbolic 181GCOV_PROFILE := n 182 183quiet_cmd_vdso_and_check = VDSO $@ 184 cmd_vdso_and_check = $(cmd_vdso); $(cmd_vdso_check) 185 186# 187# Install the unstripped copies of vdso*.so. If our toolchain supports 188# build-id, install .build-id links as well. 189# 190quiet_cmd_vdso_install = INSTALL $(@:install_%=%) 191define cmd_vdso_install 192 cp $< "$(MODLIB)/vdso/$(@:install_%=%)"; \ 193 if readelf -n $< |grep -q 'Build ID'; then \ 194 buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \ 195 first=`echo $$buildid | cut -b-2`; \ 196 last=`echo $$buildid | cut -b3-`; \ 197 mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \ 198 ln -sf "../../$(@:install_%=%)" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \ 199 fi 200endef 201 202vdso_img_insttargets := $(vdso_img_sodbg:%.dbg=install_%) 203 204$(MODLIB)/vdso: FORCE 205 @mkdir -p $(MODLIB)/vdso 206 207$(vdso_img_insttargets): install_%: $(obj)/%.dbg $(MODLIB)/vdso 208 $(call cmd,vdso_install) 209 210PHONY += vdso_install $(vdso_img_insttargets) 211vdso_install: $(vdso_img_insttargets) 212 213clean-files := vdso32.so vdso32.so.dbg vdso64* vdso-image-*.c vdsox32.so* 214