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