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