arch/x86/entry/vdso/Makefile

   1 # SPDX-License-Identifier: GPL-2.0
   2 #
   3 # Building vDSO images for x86.
   4 #
   5
   6 KBUILD_CFLAGS += $(DISABLE_LTO)
   7 KASAN_SANITIZE                  := n
   8 UBSAN_SANITIZE                  := n
   9 OBJECT_FILES_NON_STANDARD       := y
  10
  11 # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
  12 KCOV_INSTRUMENT         := n
  13
  14 VDSO64-$(CONFIG_X86_64)         := y
  15 VDSOX32-$(CONFIG_X86_X32_ABI)   := y
  16 VDSO32-$(CONFIG_X86_32)         := y
  17 VDSO32-$(CONFIG_IA32_EMULATION) := y
  18
  19 # files to link into the vdso
  20 vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
  21
  22 # files to link into kernel
  23 obj-y                           += vma.o
  24 OBJECT_FILES_NON_STANDARD_vma.o := n
  25
  26 # vDSO images to build
  27 vdso_img-$(VDSO64-y)            += 64
  28 vdso_img-$(VDSOX32-y)           += x32
  29 vdso_img-$(VDSO32-y)            += 32
  30
  31 obj-$(VDSO32-y)                 += vdso32-setup.o
  32
  33 vobjs := $(foreach F,$(vobjs-y),$(obj)/$F)
  34
  35 $(obj)/vdso.o: $(obj)/vdso.so
  36
  37 targets += vdso.lds $(vobjs-y)
  38
  39 # Build the vDSO image C files and link them in.
  40 vdso_img_objs := $(vdso_img-y:%=vdso-image-%.o)
  41 vdso_img_cfiles := $(vdso_img-y:%=vdso-image-%.c)
  42 vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg)
  43 obj-y += $(vdso_img_objs)
  44 targets += $(vdso_img_cfiles)
  45 targets += $(vdso_img_sodbg)
  46 .SECONDARY: $(vdso_img-y:%=$(obj)/vdso-image-%.c) \
  47         $(vdso_img-y:%=$(obj)/vdso%.so)
  48
  49 export CPPFLAGS_vdso.lds += -P -C
  50
  51 VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --no-undefined \
  52                         -z max-page-size=4096
  53
  54 $(obj)/vdso64.so.dbg: $(src)/vdso.lds $(vobjs) FORCE
  55         $(call if_changed,vdso)
  56
  57 HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/$(SUBARCH)/include/uapi
  58 hostprogs-y                     += vdso2c
  59
  60 quiet_cmd_vdso2c = VDSO2C  $@
  61 define cmd_vdso2c
  62         $(obj)/vdso2c $< $(<:%.dbg=%) $@
  63 endef
  64
  65 $(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE
  66         $(call if_changed,vdso2c)
  67
  68 #
  69 # Don't omit frame pointers for ease of userspace debugging, but do
  70 # optimize sibling calls.
  71 #
  72 CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \
  73        $(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \
  74        -fno-omit-frame-pointer -foptimize-sibling-calls \
  75        -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
  76
  77 ifdef CONFIG_RETPOLINE
  78 ifneq ($(RETPOLINE_VDSO_CFLAGS),)
  79   CFL += $(RETPOLINE_VDSO_CFLAGS)
  80 endif
  81 endif
  82
  83 $(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL)
  84
  85 #
  86 # vDSO code runs in userspace and -pg doesn't help with profiling anyway.
  87 #
  88 CFLAGS_REMOVE_vdso-note.o = -pg
  89 CFLAGS_REMOVE_vclock_gettime.o = -pg
  90 CFLAGS_REMOVE_vgetcpu.o = -pg
  91 CFLAGS_REMOVE_vvar.o = -pg
  92
  93 #
  94 # X32 processes use x32 vDSO to access 64bit kernel data.
  95 #
  96 # Build x32 vDSO image:
  97 # 1. Compile x32 vDSO as 64bit.
  98 # 2. Convert object files to x32.
  99 # 3. Build x32 VDSO image with x32 objects, which contains 64bit codes
 100 # so that it can reach 64bit address space with 64bit pointers.
 101 #
 102
 103 CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds)
 104 VDSO_LDFLAGS_vdsox32.lds = -m elf32_x86_64 -soname linux-vdso.so.1 \
 105                            -z max-page-size=4096
 106
 107 # 64-bit objects to re-brand as x32
 108 vobjs64-for-x32 := $(filter-out $(vobjs-nox32),$(vobjs-y))
 109
 110 # x32-rebranded versions
 111 vobjx32s-y := $(vobjs64-for-x32:.o=-x32.o)
 112
 113 # same thing, but in the output directory
 114 vobjx32s := $(foreach F,$(vobjx32s-y),$(obj)/$F)
 115
 116 # Convert 64bit object file to x32 for x32 vDSO.
 117 quiet_cmd_x32 = X32     $@
 118       cmd_x32 = $(OBJCOPY) -O elf32-x86-64 $< $@
 119
 120 $(obj)/%-x32.o: $(obj)/%.o FORCE
 121         $(call if_changed,x32)
 122
 123 targets += vdsox32.lds $(vobjx32s-y)
 124
 125 $(obj)/%.so: OBJCOPYFLAGS := -S
 126 $(obj)/%.so: $(obj)/%.so.dbg
 127         $(call if_changed,objcopy)
 128
 129 $(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds $(vobjx32s) FORCE
 130         $(call if_changed,vdso)
 131
 132 CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds)
 133 VDSO_LDFLAGS_vdso32.lds = -m elf_i386 -soname linux-gate.so.1
 134
 135 # This makes sure the $(obj) subdirectory exists even though vdso32/
 136 # is not a kbuild sub-make subdirectory.
 137 override obj-dirs = $(dir $(obj)) $(obj)/vdso32/
 138
 139 targets += vdso32/vdso32.lds
 140 targets += vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o
 141 targets += vdso32/vclock_gettime.o
 142
 143 KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS)) -DBUILD_VDSO
 144 $(obj)/vdso32.so.dbg: KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
 145 $(obj)/vdso32.so.dbg: asflags-$(CONFIG_X86_64) += -m32
 146
 147 KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
 148 KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
 149 KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
 150 KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
 151 KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32))
 152 KBUILD_CFLAGS_32 := $(filter-out $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS_32))
 153 KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
 154 KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector)
 155 KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)
 156 KBUILD_CFLAGS_32 += -fno-omit-frame-pointer
 157 KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING
 158
 159 ifdef CONFIG_RETPOLINE
 160 ifneq ($(RETPOLINE_VDSO_CFLAGS),)
 161   KBUILD_CFLAGS_32 += $(RETPOLINE_VDSO_CFLAGS)
 162 endif
 163 endif
 164
 165 $(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
 166
 167 $(obj)/vdso32.so.dbg: FORCE \
 168                       $(obj)/vdso32/vdso32.lds \
 169                       $(obj)/vdso32/vclock_gettime.o \
 170                       $(obj)/vdso32/note.o \
 171                       $(obj)/vdso32/system_call.o \
 172                       $(obj)/vdso32/sigreturn.o
 173         $(call if_changed,vdso)
 174
 175 #
 176 # The DSO images are built using a special linker script.
 177 #
 178 quiet_cmd_vdso = VDSO    $@
 179       cmd_vdso = $(LD) -nostdlib -o $@ \
 180                        $(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \
 181                        -T $(filter %.lds,$^) $(filter %.o,$^) && \
 182                  sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@'
 183
 184 VDSO_LDFLAGS = -shared $(call ld-option, --hash-style=both) \
 185         $(call ld-option, --build-id) -Bsymbolic
 186 GCOV_PROFILE := n
 187
 188 #
 189 # Install the unstripped copies of vdso*.so.  If our toolchain supports
 190 # build-id, install .build-id links as well.
 191 #
 192 quiet_cmd_vdso_install = INSTALL $(@:install_%=%)
 193 define cmd_vdso_install
 194         cp $< "$(MODLIB)/vdso/$(@:install_%=%)"; \
 195         if readelf -n $< |grep -q 'Build ID'; then \
 196           buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \
 197           first=`echo $$buildid | cut -b-2`; \
 198           last=`echo $$buildid | cut -b3-`; \
 199           mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \
 200           ln -sf "../../$(@:install_%=%)" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \
 201         fi
 202 endef
 203
 204 vdso_img_insttargets := $(vdso_img_sodbg:%.dbg=install_%)
 205
 206 $(MODLIB)/vdso: FORCE
 207         @mkdir -p $(MODLIB)/vdso
 208
 209 $(vdso_img_insttargets): install_%: $(obj)/%.dbg $(MODLIB)/vdso
 210         $(call cmd,vdso_install)
 211
 212 PHONY += vdso_install $(vdso_img_insttargets)
 213 vdso_install: $(vdso_img_insttargets)
 214
 215 clean-files := vdso32.so vdso32.so.dbg vdso64* vdso-image-*.c vdsox32.so*