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