1# 2# Building vDSO images for x86. 3# 4 5KBUILD_CFLAGS += $(DISABLE_LTO) 6KASAN_SANITIZE := n 7 8VDSO64-$(CONFIG_X86_64) := y 9VDSOX32-$(CONFIG_X86_X32_ABI) := y 10VDSO32-$(CONFIG_X86_32) := y 11VDSO32-$(CONFIG_IA32_EMULATION) := y 12 13# files to link into the vdso 14vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o 15 16# files to link into kernel 17obj-y += vma.o 18 19# vDSO images to build 20vdso_img-$(VDSO64-y) += 64 21vdso_img-$(VDSOX32-y) += x32 22vdso_img-$(VDSO32-y) += 32-int80 23vdso_img-$(CONFIG_IA32_EMULATION) += 32-syscall 24vdso_img-$(VDSO32-y) += 32-sysenter 25 26obj-$(VDSO32-y) += vdso32-setup.o 27 28vobjs := $(foreach F,$(vobjs-y),$(obj)/$F) 29 30$(obj)/vdso.o: $(obj)/vdso.so 31 32targets += vdso.lds $(vobjs-y) 33 34# Build the vDSO image C files and link them in. 35vdso_img_objs := $(vdso_img-y:%=vdso-image-%.o) 36vdso_img_cfiles := $(vdso_img-y:%=vdso-image-%.c) 37vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg) 38obj-y += $(vdso_img_objs) 39targets += $(vdso_img_cfiles) 40targets += $(vdso_img_sodbg) 41.SECONDARY: $(vdso_img-y:%=$(obj)/vdso-image-%.c) \ 42 $(vdso_img-y:%=$(obj)/vdso%.so) 43 44export CPPFLAGS_vdso.lds += -P -C 45 46VDSO_LDFLAGS_vdso.lds = -m64 -Wl,-soname=linux-vdso.so.1 \ 47 -Wl,--no-undefined \ 48 -Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096 \ 49 $(DISABLE_LTO) 50 51$(obj)/vdso64.so.dbg: $(src)/vdso.lds $(vobjs) FORCE 52 $(call if_changed,vdso) 53 54HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/x86/include/uapi 55hostprogs-y += vdso2c 56 57quiet_cmd_vdso2c = VDSO2C $@ 58define cmd_vdso2c 59 $(obj)/vdso2c $< $(<:%.dbg=%) $@ 60endef 61 62$(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE 63 $(call if_changed,vdso2c) 64 65# 66# Don't omit frame pointers for ease of userspace debugging, but do 67# optimize sibling calls. 68# 69CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \ 70 $(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \ 71 -fno-omit-frame-pointer -foptimize-sibling-calls \ 72 -DDISABLE_BRANCH_PROFILING 73 74$(vobjs): KBUILD_CFLAGS += $(CFL) 75 76# 77# vDSO code runs in userspace and -pg doesn't help with profiling anyway. 78# 79CFLAGS_REMOVE_vdso-note.o = -pg 80CFLAGS_REMOVE_vclock_gettime.o = -pg 81CFLAGS_REMOVE_vgetcpu.o = -pg 82CFLAGS_REMOVE_vvar.o = -pg 83 84# 85# X32 processes use x32 vDSO to access 64bit kernel data. 86# 87# Build x32 vDSO image: 88# 1. Compile x32 vDSO as 64bit. 89# 2. Convert object files to x32. 90# 3. Build x32 VDSO image with x32 objects, which contains 64bit codes 91# so that it can reach 64bit address space with 64bit pointers. 92# 93 94CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds) 95VDSO_LDFLAGS_vdsox32.lds = -Wl,-m,elf32_x86_64 \ 96 -Wl,-soname=linux-vdso.so.1 \ 97 -Wl,-z,max-page-size=4096 \ 98 -Wl,-z,common-page-size=4096 99 100# 64-bit objects to re-brand as x32 101vobjs64-for-x32 := $(filter-out $(vobjs-nox32),$(vobjs-y)) 102 103# x32-rebranded versions 104vobjx32s-y := $(vobjs64-for-x32:.o=-x32.o) 105 106# same thing, but in the output directory 107vobjx32s := $(foreach F,$(vobjx32s-y),$(obj)/$F) 108 109# Convert 64bit object file to x32 for x32 vDSO. 110quiet_cmd_x32 = X32 $@ 111 cmd_x32 = $(OBJCOPY) -O elf32-x86-64 $< $@ 112 113$(obj)/%-x32.o: $(obj)/%.o FORCE 114 $(call if_changed,x32) 115 116targets += vdsox32.lds $(vobjx32s-y) 117 118$(obj)/%.so: OBJCOPYFLAGS := -S 119$(obj)/%.so: $(obj)/%.so.dbg 120 $(call if_changed,objcopy) 121 122$(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds $(vobjx32s) FORCE 123 $(call if_changed,vdso) 124 125# 126# Build multiple 32-bit vDSO images to choose from at boot time. 127# 128vdso32.so-$(VDSO32-y) += int80 129vdso32.so-$(CONFIG_IA32_EMULATION) += syscall 130vdso32.so-$(VDSO32-y) += sysenter 131 132vdso32-images = $(vdso32.so-y:%=vdso32-%.so) 133 134CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds) 135VDSO_LDFLAGS_vdso32.lds = -m32 -Wl,-m,elf_i386 -Wl,-soname=linux-gate.so.1 136 137# This makes sure the $(obj) subdirectory exists even though vdso32/ 138# is not a kbuild sub-make subdirectory. 139override obj-dirs = $(dir $(obj)) $(obj)/vdso32/ 140 141targets += vdso32/vdso32.lds 142targets += vdso32/note.o vdso32/vclock_gettime.o $(vdso32.so-y:%=vdso32/%.o) 143targets += vdso32/vclock_gettime.o 144 145$(obj)/vdso32.o: $(vdso32-images:%=$(obj)/%) 146 147KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS)) 148$(vdso32-images:%=$(obj)/%.dbg): KBUILD_AFLAGS = $(KBUILD_AFLAGS_32) 149$(vdso32-images:%=$(obj)/%.dbg): asflags-$(CONFIG_X86_64) += -m32 150 151KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS)) 152KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32)) 153KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32)) 154KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32)) 155KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic 156KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector) 157KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls) 158KBUILD_CFLAGS_32 += -fno-omit-frame-pointer 159KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING 160$(vdso32-images:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_32) 161 162$(vdso32-images:%=$(obj)/%.dbg): $(obj)/vdso32-%.so.dbg: FORCE \ 163 $(obj)/vdso32/vdso32.lds \ 164 $(obj)/vdso32/vclock_gettime.o \ 165 $(obj)/vdso32/note.o \ 166 $(obj)/vdso32/%.o 167 $(call if_changed,vdso) 168 169# 170# The DSO images are built using a special linker script. 171# 172quiet_cmd_vdso = VDSO $@ 173 cmd_vdso = $(CC) -nostdlib -o $@ \ 174 $(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \ 175 -Wl,-T,$(filter %.lds,$^) $(filter %.o,$^) && \ 176 sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@' 177 178VDSO_LDFLAGS = -fPIC -shared $(call cc-ldoption, -Wl$(comma)--hash-style=both) \ 179 $(call cc-ldoption, -Wl$(comma)--build-id) -Wl,-Bsymbolic $(LTO_CFLAGS) 180GCOV_PROFILE := n 181 182# 183# Install the unstripped copies of vdso*.so. If our toolchain supports 184# build-id, install .build-id links as well. 185# 186quiet_cmd_vdso_install = INSTALL $(@:install_%=%) 187define cmd_vdso_install 188 cp $< "$(MODLIB)/vdso/$(@:install_%=%)"; \ 189 if readelf -n $< |grep -q 'Build ID'; then \ 190 buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \ 191 first=`echo $$buildid | cut -b-2`; \ 192 last=`echo $$buildid | cut -b3-`; \ 193 mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \ 194 ln -sf "../../$(@:install_%=%)" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \ 195 fi 196endef 197 198vdso_img_insttargets := $(vdso_img_sodbg:%.dbg=install_%) 199 200$(MODLIB)/vdso: FORCE 201 @mkdir -p $(MODLIB)/vdso 202 203$(vdso_img_insttargets): install_%: $(obj)/%.dbg $(MODLIB)/vdso FORCE 204 $(call cmd,vdso_install) 205 206PHONY += vdso_install $(vdso_img_insttargets) 207vdso_install: $(vdso_img_insttargets) FORCE 208 209clean-files := vdso32-syscall* vdso32-sysenter* vdso32-int80* vdso64* vdso-image-*.c vdsox32.so* 210