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 $(srctree)/lib/vdso/Makefile 11 12# Sanitizer runtimes are unavailable and cannot be linked here. 13KASAN_SANITIZE := n 14UBSAN_SANITIZE := n 15KCSAN_SANITIZE := n 16OBJECT_FILES_NON_STANDARD := y 17 18# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in. 19KCOV_INSTRUMENT := n 20 21VDSO64-$(CONFIG_X86_64) := y 22VDSOX32-$(CONFIG_X86_X32_ABI) := y 23VDSO32-$(CONFIG_X86_32) := y 24VDSO32-$(CONFIG_IA32_EMULATION) := y 25 26# files to link into the vdso 27vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o 28vobjs32-y := vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o 29vobjs32-y += vdso32/vclock_gettime.o 30 31# files to link into kernel 32obj-y += vma.o 33KASAN_SANITIZE_vma.o := y 34UBSAN_SANITIZE_vma.o := y 35KCSAN_SANITIZE_vma.o := y 36OBJECT_FILES_NON_STANDARD_vma.o := n 37 38# vDSO images to build 39vdso_img-$(VDSO64-y) += 64 40vdso_img-$(VDSOX32-y) += x32 41vdso_img-$(VDSO32-y) += 32 42 43obj-$(VDSO32-y) += vdso32-setup.o 44 45vobjs := $(foreach F,$(vobjs-y),$(obj)/$F) 46vobjs32 := $(foreach F,$(vobjs32-y),$(obj)/$F) 47 48$(obj)/vdso.o: $(obj)/vdso.so 49 50targets += vdso.lds $(vobjs-y) 51targets += vdso32/vdso32.lds $(vobjs32-y) 52 53# Build the vDSO image C files and link them in. 54vdso_img_objs := $(vdso_img-y:%=vdso-image-%.o) 55vdso_img_cfiles := $(vdso_img-y:%=vdso-image-%.c) 56vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg) 57obj-y += $(vdso_img_objs) 58targets += $(vdso_img_cfiles) 59targets += $(vdso_img_sodbg) $(vdso_img-y:%=vdso%.so) 60 61CPPFLAGS_vdso.lds += -P -C 62 63VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --no-undefined \ 64 -z max-page-size=4096 65 66$(obj)/vdso64.so.dbg: $(obj)/vdso.lds $(vobjs) FORCE 67 $(call if_changed,vdso_and_check) 68 69HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/$(SUBARCH)/include/uapi 70hostprogs += vdso2c 71 72quiet_cmd_vdso2c = VDSO2C $@ 73 cmd_vdso2c = $(obj)/vdso2c $< $(<:%.dbg=%) $@ 74 75$(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE 76 $(call if_changed,vdso2c) 77 78# 79# Don't omit frame pointers for ease of userspace debugging, but do 80# optimize sibling calls. 81# 82CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \ 83 $(filter -g%,$(KBUILD_CFLAGS)) -fno-stack-protector \ 84 -fno-omit-frame-pointer -foptimize-sibling-calls \ 85 -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO 86 87ifdef CONFIG_RETPOLINE 88ifneq ($(RETPOLINE_VDSO_CFLAGS),) 89 CFL += $(RETPOLINE_VDSO_CFLAGS) 90endif 91endif 92 93$(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL) 94 95# 96# vDSO code runs in userspace and -pg doesn't help with profiling anyway. 97# 98CFLAGS_REMOVE_vclock_gettime.o = -pg 99CFLAGS_REMOVE_vdso32/vclock_gettime.o = -pg 100CFLAGS_REMOVE_vgetcpu.o = -pg 101 102# 103# X32 processes use x32 vDSO to access 64bit kernel data. 104# 105# Build x32 vDSO image: 106# 1. Compile x32 vDSO as 64bit. 107# 2. Convert object files to x32. 108# 3. Build x32 VDSO image with x32 objects, which contains 64bit codes 109# so that it can reach 64bit address space with 64bit pointers. 110# 111 112CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds) 113VDSO_LDFLAGS_vdsox32.lds = -m elf32_x86_64 -soname linux-vdso.so.1 \ 114 -z max-page-size=4096 115 116# x32-rebranded versions 117vobjx32s-y := $(vobjs-y:.o=-x32.o) 118 119# same thing, but in the output directory 120vobjx32s := $(foreach F,$(vobjx32s-y),$(obj)/$F) 121 122# Convert 64bit object file to x32 for x32 vDSO. 123quiet_cmd_x32 = X32 $@ 124 cmd_x32 = $(OBJCOPY) -O elf32-x86-64 $< $@ 125 126$(obj)/%-x32.o: $(obj)/%.o FORCE 127 $(call if_changed,x32) 128 129targets += vdsox32.lds $(vobjx32s-y) 130 131$(obj)/%.so: OBJCOPYFLAGS := -S 132$(obj)/%.so: $(obj)/%.so.dbg FORCE 133 $(call if_changed,objcopy) 134 135$(obj)/vdsox32.so.dbg: $(obj)/vdsox32.lds $(vobjx32s) FORCE 136 $(call if_changed,vdso_and_check) 137 138CPPFLAGS_vdso32/vdso32.lds = $(CPPFLAGS_vdso.lds) 139VDSO_LDFLAGS_vdso32.lds = -m elf_i386 -soname linux-gate.so.1 140 141KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS)) -DBUILD_VDSO 142$(obj)/vdso32.so.dbg: KBUILD_AFLAGS = $(KBUILD_AFLAGS_32) 143$(obj)/vdso32.so.dbg: asflags-$(CONFIG_X86_64) += -m32 144 145KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS)) 146KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32)) 147KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32)) 148KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32)) 149KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32)) 150KBUILD_CFLAGS_32 := $(filter-out $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS_32)) 151KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic 152KBUILD_CFLAGS_32 += -fno-stack-protector 153KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls) 154KBUILD_CFLAGS_32 += -fno-omit-frame-pointer 155KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING 156 157ifdef CONFIG_RETPOLINE 158ifneq ($(RETPOLINE_VDSO_CFLAGS),) 159 KBUILD_CFLAGS_32 += $(RETPOLINE_VDSO_CFLAGS) 160endif 161endif 162 163$(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32) 164 165$(obj)/vdso32.so.dbg: $(obj)/vdso32/vdso32.lds $(vobjs32) FORCE 166 $(call if_changed,vdso_and_check) 167 168# 169# The DSO images are built using a special linker script. 170# 171quiet_cmd_vdso = VDSO $@ 172 cmd_vdso = $(LD) -nostdlib -o $@ \ 173 $(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \ 174 -T $(filter %.lds,$^) $(filter %.o,$^) && \ 175 sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@' 176 177VDSO_LDFLAGS = -shared --hash-style=both --build-id=sha1 \ 178 $(call ld-option, --eh-frame-hdr) -Bsymbolic 179GCOV_PROFILE := n 180 181quiet_cmd_vdso_and_check = VDSO $@ 182 cmd_vdso_and_check = $(cmd_vdso); $(cmd_vdso_check) 183 184# 185# Install the unstripped copies of vdso*.so. If our toolchain supports 186# build-id, install .build-id links as well. 187# 188quiet_cmd_vdso_install = INSTALL $(@:install_%=%) 189define cmd_vdso_install 190 cp $< "$(MODLIB)/vdso/$(@:install_%=%)"; \ 191 if readelf -n $< |grep -q 'Build ID'; then \ 192 buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \ 193 first=`echo $$buildid | cut -b-2`; \ 194 last=`echo $$buildid | cut -b3-`; \ 195 mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \ 196 ln -sf "../../$(@:install_%=%)" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \ 197 fi 198endef 199 200vdso_img_insttargets := $(vdso_img_sodbg:%.dbg=install_%) 201 202$(MODLIB)/vdso: FORCE 203 @mkdir -p $(MODLIB)/vdso 204 205$(vdso_img_insttargets): install_%: $(obj)/%.dbg $(MODLIB)/vdso 206 $(call cmd,vdso_install) 207 208PHONY += vdso_install $(vdso_img_insttargets) 209vdso_install: $(vdso_img_insttargets) 210 211clean-files := vdso32.so vdso32.so.dbg vdso64* vdso-image-*.c vdsox32.so* 212