1# SPDX-License-Identifier: GPL-2.0 2# 3# Building vDSO images for x86. 4# 5 6KBUILD_CFLAGS += $(DISABLE_LTO) 7KASAN_SANITIZE := n 8UBSAN_SANITIZE := n 9OBJECT_FILES_NON_STANDARD := y 10 11# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in. 12KCOV_INSTRUMENT := n 13 14VDSO64-$(CONFIG_X86_64) := y 15VDSOX32-$(CONFIG_X86_X32_ABI) := y 16VDSO32-$(CONFIG_X86_32) := y 17VDSO32-$(CONFIG_IA32_EMULATION) := y 18 19# files to link into the vdso 20vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o 21 22# files to link into kernel 23obj-y += vma.o 24OBJECT_FILES_NON_STANDARD_vma.o := n 25 26# vDSO images to build 27vdso_img-$(VDSO64-y) += 64 28vdso_img-$(VDSOX32-y) += x32 29vdso_img-$(VDSO32-y) += 32 30 31obj-$(VDSO32-y) += vdso32-setup.o 32 33vobjs := $(foreach F,$(vobjs-y),$(obj)/$F) 34 35$(obj)/vdso.o: $(obj)/vdso.so 36 37targets += vdso.lds $(vobjs-y) 38 39# Build the vDSO image C files and link them in. 40vdso_img_objs := $(vdso_img-y:%=vdso-image-%.o) 41vdso_img_cfiles := $(vdso_img-y:%=vdso-image-%.c) 42vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg) 43obj-y += $(vdso_img_objs) 44targets += $(vdso_img_cfiles) 45targets += $(vdso_img_sodbg) 46.SECONDARY: $(vdso_img-y:%=$(obj)/vdso-image-%.c) \ 47 $(vdso_img-y:%=$(obj)/vdso%.so) 48 49export CPPFLAGS_vdso.lds += -P -C 50 51VDSO_LDFLAGS_vdso.lds = -m64 -Wl,-soname=linux-vdso.so.1 \ 52 -Wl,--no-undefined \ 53 -Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096 \ 54 $(DISABLE_LTO) 55 56$(obj)/vdso64.so.dbg: $(src)/vdso.lds $(vobjs) FORCE 57 $(call if_changed,vdso) 58 59HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/$(SUBARCH)/include/uapi 60hostprogs-y += vdso2c 61 62quiet_cmd_vdso2c = VDSO2C $@ 63define cmd_vdso2c 64 $(obj)/vdso2c $< $(<:%.dbg=%) $@ 65endef 66 67$(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)) $(call cc-option, -fno-stack-protector) \ 76 -fno-omit-frame-pointer -foptimize-sibling-calls \ 77 -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO 78 79$(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS)) $(CFL) 80 81# 82# vDSO code runs in userspace and -pg doesn't help with profiling anyway. 83# 84CFLAGS_REMOVE_vdso-note.o = -pg 85CFLAGS_REMOVE_vclock_gettime.o = -pg 86CFLAGS_REMOVE_vgetcpu.o = -pg 87CFLAGS_REMOVE_vvar.o = -pg 88 89# 90# X32 processes use x32 vDSO to access 64bit kernel data. 91# 92# Build x32 vDSO image: 93# 1. Compile x32 vDSO as 64bit. 94# 2. Convert object files to x32. 95# 3. Build x32 VDSO image with x32 objects, which contains 64bit codes 96# so that it can reach 64bit address space with 64bit pointers. 97# 98 99CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds) 100VDSO_LDFLAGS_vdsox32.lds = -Wl,-m,elf32_x86_64 \ 101 -Wl,-soname=linux-vdso.so.1 \ 102 -Wl,-z,max-page-size=4096 \ 103 -Wl,-z,common-page-size=4096 104 105# 64-bit objects to re-brand as x32 106vobjs64-for-x32 := $(filter-out $(vobjs-nox32),$(vobjs-y)) 107 108# x32-rebranded versions 109vobjx32s-y := $(vobjs64-for-x32:.o=-x32.o) 110 111# same thing, but in the output directory 112vobjx32s := $(foreach F,$(vobjx32s-y),$(obj)/$F) 113 114# Convert 64bit object file to x32 for x32 vDSO. 115quiet_cmd_x32 = X32 $@ 116 cmd_x32 = $(OBJCOPY) -O elf32-x86-64 $< $@ 117 118$(obj)/%-x32.o: $(obj)/%.o FORCE 119 $(call if_changed,x32) 120 121targets += vdsox32.lds $(vobjx32s-y) 122 123$(obj)/%.so: OBJCOPYFLAGS := -S 124$(obj)/%.so: $(obj)/%.so.dbg 125 $(call if_changed,objcopy) 126 127$(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds $(vobjx32s) FORCE 128 $(call if_changed,vdso) 129 130CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds) 131VDSO_LDFLAGS_vdso32.lds = -m32 -Wl,-m,elf_i386 -Wl,-soname=linux-gate.so.1 132 133targets += vdso32/vdso32.lds 134targets += vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o 135targets += vdso32/vclock_gettime.o 136 137KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS)) -DBUILD_VDSO 138$(obj)/vdso32.so.dbg: KBUILD_AFLAGS = $(KBUILD_AFLAGS_32) 139$(obj)/vdso32.so.dbg: asflags-$(CONFIG_X86_64) += -m32 140 141KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS)) 142KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32)) 143KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32)) 144KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32)) 145KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32)) 146KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic 147KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector) 148KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls) 149KBUILD_CFLAGS_32 += -fno-omit-frame-pointer 150KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING 151$(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32) 152 153$(obj)/vdso32.so.dbg: FORCE \ 154 $(obj)/vdso32/vdso32.lds \ 155 $(obj)/vdso32/vclock_gettime.o \ 156 $(obj)/vdso32/note.o \ 157 $(obj)/vdso32/system_call.o \ 158 $(obj)/vdso32/sigreturn.o 159 $(call if_changed,vdso) 160 161# 162# The DSO images are built using a special linker script. 163# 164quiet_cmd_vdso = VDSO $@ 165 cmd_vdso = $(CC) -nostdlib -o $@ \ 166 $(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \ 167 -Wl,-T,$(filter %.lds,$^) $(filter %.o,$^) && \ 168 sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@' 169 170VDSO_LDFLAGS = -fPIC -shared $(call cc-ldoption, -Wl$(comma)--hash-style=both) \ 171 $(call cc-ldoption, -Wl$(comma)--build-id) -Wl,-Bsymbolic $(LTO_CFLAGS) 172GCOV_PROFILE := n 173 174# 175# Install the unstripped copies of vdso*.so. If our toolchain supports 176# build-id, install .build-id links as well. 177# 178quiet_cmd_vdso_install = INSTALL $(@:install_%=%) 179define cmd_vdso_install 180 cp $< "$(MODLIB)/vdso/$(@:install_%=%)"; \ 181 if readelf -n $< |grep -q 'Build ID'; then \ 182 buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \ 183 first=`echo $$buildid | cut -b-2`; \ 184 last=`echo $$buildid | cut -b3-`; \ 185 mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \ 186 ln -sf "../../$(@:install_%=%)" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \ 187 fi 188endef 189 190vdso_img_insttargets := $(vdso_img_sodbg:%.dbg=install_%) 191 192$(MODLIB)/vdso: FORCE 193 @mkdir -p $(MODLIB)/vdso 194 195$(vdso_img_insttargets): install_%: $(obj)/%.dbg $(MODLIB)/vdso 196 $(call cmd,vdso_install) 197 198PHONY += vdso_install $(vdso_img_insttargets) 199vdso_install: $(vdso_img_insttargets) 200 201clean-files := vdso32.so vdso32.so.dbg vdso64* vdso-image-*.c vdsox32.so* 202