arch/x86/entry/vdso/Makefile

   1 #
   2 # Building vDSO images for x86.
   3 #
   4
   5 KBUILD_CFLAGS += $(DISABLE_LTO)
   6 KASAN_SANITIZE := n
   7 UBSAN_SANITIZE := n
   8
   9 VDSO64-$(CONFIG_X86_64)         := y
  10 VDSOX32-$(CONFIG_X86_X32_ABI)   := y
  11 VDSO32-$(CONFIG_X86_32)         := y
  12 VDSO32-$(CONFIG_IA32_EMULATION) := y
  13
  14 # files to link into the vdso
  15 vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
  16
  17 # files to link into kernel
  18 obj-y                           += vma.o
  19
  20 # vDSO images to build
  21 vdso_img-$(VDSO64-y)            += 64
  22 vdso_img-$(VDSOX32-y)           += x32
  23 vdso_img-$(VDSO32-y)            += 32
  24
  25 obj-$(VDSO32-y)                 += vdso32-setup.o
  26
  27 vobjs := $(foreach F,$(vobjs-y),$(obj)/$F)
  28
  29 $(obj)/vdso.o: $(obj)/vdso.so
  30
  31 targets += vdso.lds $(vobjs-y)
  32
  33 # Build the vDSO image C files and link them in.
  34 vdso_img_objs := $(vdso_img-y:%=vdso-image-%.o)
  35 vdso_img_cfiles := $(vdso_img-y:%=vdso-image-%.c)
  36 vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg)
  37 obj-y += $(vdso_img_objs)
  38 targets += $(vdso_img_cfiles)
  39 targets += $(vdso_img_sodbg)
  40 .SECONDARY: $(vdso_img-y:%=$(obj)/vdso-image-%.c) \
  41         $(vdso_img-y:%=$(obj)/vdso%.so)
  42
  43 export CPPFLAGS_vdso.lds += -P -C
  44
  45 VDSO_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         $(call if_changed,vdso)
  52
  53 HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/x86/include/uapi
  54 hostprogs-y                     += vdso2c
  55
  56 quiet_cmd_vdso2c = VDSO2C  $@
  57 define cmd_vdso2c
  58         $(obj)/vdso2c $< $(<:%.dbg=%) $@
  59 endef
  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 #
  68 CFL := $(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 #
  78 CFLAGS_REMOVE_vdso-note.o = -pg
  79 CFLAGS_REMOVE_vclock_gettime.o = -pg
  80 CFLAGS_REMOVE_vgetcpu.o = -pg
  81 CFLAGS_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
  93 CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds)
  94 VDSO_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
 100 vobjs64-for-x32 := $(filter-out $(vobjs-nox32),$(vobjs-y))
 101
 102 # x32-rebranded versions
 103 vobjx32s-y := $(vobjs64-for-x32:.o=-x32.o)
 104
 105 # same thing, but in the output directory
 106 vobjx32s := $(foreach F,$(vobjx32s-y),$(obj)/$F)
 107
 108 # Convert 64bit object file to x32 for x32 vDSO.
 109 quiet_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
 115 targets += 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
 124 CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds)
 125 VDSO_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.
 129 override obj-dirs = $(dir $(obj)) $(obj)/vdso32/
 130
 131 targets += vdso32/vdso32.lds
 132 targets += vdso32/note.o vdso32/vclock_gettime.o vdso32/system_call.o
 133 targets += vdso32/vclock_gettime.o
 134
 135 KBUILD_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
 139 KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
 140 KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
 141 KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
 142 KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
 143 KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
 144 KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector)
 145 KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)
 146 KBUILD_CFLAGS_32 += -fno-omit-frame-pointer
 147 KBUILD_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 #
 160 quiet_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
 166 VDSO_LDFLAGS = -fPIC -shared $(call cc-ldoption, -Wl$(comma)--hash-style=both) \
 167         $(call cc-ldoption, -Wl$(comma)--build-id) -Wl,-Bsymbolic $(LTO_CFLAGS)
 168 GCOV_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 #
 174 quiet_cmd_vdso_install = INSTALL $(@:install_%=%)
 175 define 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
 184 endef
 185
 186 vdso_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
 194 PHONY += vdso_install $(vdso_img_insttargets)
 195 vdso_install: $(vdso_img_insttargets) FORCE
 196
 197 clean-files := vdso32.so vdso32.so.dbg vdso64* vdso-image-*.c vdsox32.so*