arch/x86/entry/vdso/Makefile

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