kernel/arch/x86/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-$(CONFIG_COMPAT)         := y
  12
  13 # files to link into the vdso
  14 vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
  15
  16 # files to link into kernel
  17 obj-y                           += vma.o
  18
  19 # vDSO images to build
  20 vdso_img-$(VDSO64-y)            += 64
  21 vdso_img-$(VDSOX32-y)           += x32
  22 vdso_img-$(VDSO32-y)            += 32-int80
  23 vdso_img-$(CONFIG_COMPAT)       += 32-syscall
  24 vdso_img-$(VDSO32-y)            += 32-sysenter
  25
  26 obj-$(VDSO32-y)                 += vdso32-setup.o
  27
  28 vobjs := $(foreach F,$(vobjs-y),$(obj)/$F)
  29
  30 $(obj)/vdso.o: $(obj)/vdso.so
  31
  32 targets += vdso.lds $(vobjs-y)
  33
  34 # Build the vDSO image C files and link them in.
  35 vdso_img_objs := $(vdso_img-y:%=vdso-image-%.o)
  36 vdso_img_cfiles := $(vdso_img-y:%=vdso-image-%.c)
  37 vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg)
  38 obj-y += $(vdso_img_objs)
  39 targets += $(vdso_img_cfiles)
  40 targets += $(vdso_img_sodbg)
  41 .SECONDARY: $(vdso_img-y:%=$(obj)/vdso-image-%.c) \
  42         $(vdso_img-y:%=$(obj)/vdso%.so)
  43
  44 export CPPFLAGS_vdso.lds += -P -C
  45
  46 VDSO_LDFLAGS_vdso.lds = -m64 -Wl,-soname=linux-vdso.so.1 \
  47                         -Wl,--no-undefined \
  48                         -Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096 \
  49                         $(DISABLE_LTO)
  50
  51 $(obj)/vdso64.so.dbg: $(src)/vdso.lds $(vobjs) FORCE
  52         $(call if_changed,vdso)
  53
  54 HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/x86/include/uapi
  55 hostprogs-y                     += vdso2c
  56
  57 quiet_cmd_vdso2c = VDSO2C  $@
  58 define cmd_vdso2c
  59         $(obj)/vdso2c $< $(<:%.dbg=%) $@
  60 endef
  61
  62 $(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE
  63         $(call if_changed,vdso2c)
  64
  65 #
  66 # Don't omit frame pointers for ease of userspace debugging, but do
  67 # optimize sibling calls.
  68 #
  69 CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \
  70        $(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \
  71        -fno-omit-frame-pointer -foptimize-sibling-calls \
  72        -DDISABLE_BRANCH_PROFILING
  73
  74 $(vobjs): KBUILD_CFLAGS += $(CFL)
  75
  76 #
  77 # vDSO code runs in userspace and -pg doesn't help with profiling anyway.
  78 #
  79 CFLAGS_REMOVE_vdso-note.o = -pg
  80 CFLAGS_REMOVE_vclock_gettime.o = -pg
  81 CFLAGS_REMOVE_vgetcpu.o = -pg
  82 CFLAGS_REMOVE_vvar.o = -pg
  83
  84 #
  85 # X32 processes use x32 vDSO to access 64bit kernel data.
  86 #
  87 # Build x32 vDSO image:
  88 # 1. Compile x32 vDSO as 64bit.
  89 # 2. Convert object files to x32.
  90 # 3. Build x32 VDSO image with x32 objects, which contains 64bit codes
  91 # so that it can reach 64bit address space with 64bit pointers.
  92 #
  93
  94 CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds)
  95 VDSO_LDFLAGS_vdsox32.lds = -Wl,-m,elf32_x86_64 \
  96                            -Wl,-soname=linux-vdso.so.1 \
  97                            -Wl,-z,max-page-size=4096 \
  98                            -Wl,-z,common-page-size=4096
  99
 100 # 64-bit objects to re-brand as x32
 101 vobjs64-for-x32 := $(filter-out $(vobjs-nox32),$(vobjs-y))
 102
 103 # x32-rebranded versions
 104 vobjx32s-y := $(vobjs64-for-x32:.o=-x32.o)
 105
 106 # same thing, but in the output directory
 107 vobjx32s := $(foreach F,$(vobjx32s-y),$(obj)/$F)
 108
 109 # Convert 64bit object file to x32 for x32 vDSO.
 110 quiet_cmd_x32 = X32     $@
 111       cmd_x32 = $(OBJCOPY) -O elf32-x86-64 $< $@
 112
 113 $(obj)/%-x32.o: $(obj)/%.o FORCE
 114         $(call if_changed,x32)
 115
 116 targets += vdsox32.lds $(vobjx32s-y)
 117
 118 $(obj)/%.so: OBJCOPYFLAGS := -S
 119 $(obj)/%.so: $(obj)/%.so.dbg
 120         $(call if_changed,objcopy)
 121
 122 $(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds $(vobjx32s) FORCE
 123         $(call if_changed,vdso)
 124
 125 #
 126 # Build multiple 32-bit vDSO images to choose from at boot time.
 127 #
 128 vdso32.so-$(VDSO32-y)           += int80
 129 vdso32.so-$(CONFIG_COMPAT)      += syscall
 130 vdso32.so-$(VDSO32-y)           += sysenter
 131
 132 vdso32-images                   = $(vdso32.so-y:%=vdso32-%.so)
 133
 134 CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds)
 135 VDSO_LDFLAGS_vdso32.lds = -m32 -Wl,-m,elf_i386 -Wl,-soname=linux-gate.so.1
 136
 137 # This makes sure the $(obj) subdirectory exists even though vdso32/
 138 # is not a kbuild sub-make subdirectory.
 139 override obj-dirs = $(dir $(obj)) $(obj)/vdso32/
 140
 141 targets += vdso32/vdso32.lds
 142 targets += vdso32/note.o vdso32/vclock_gettime.o $(vdso32.so-y:%=vdso32/%.o)
 143 targets += vdso32/vclock_gettime.o
 144
 145 $(obj)/vdso32.o: $(vdso32-images:%=$(obj)/%)
 146
 147 KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS))
 148 $(vdso32-images:%=$(obj)/%.dbg): KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
 149 $(vdso32-images:%=$(obj)/%.dbg): asflags-$(CONFIG_X86_64) += -m32
 150
 151 KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
 152 KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
 153 KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
 154 KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
 155 KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
 156 KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector)
 157 KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)
 158 KBUILD_CFLAGS_32 += -fno-omit-frame-pointer
 159 KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING
 160 $(vdso32-images:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
 161
 162 $(vdso32-images:%=$(obj)/%.dbg): $(obj)/vdso32-%.so.dbg: FORCE \
 163                                  $(obj)/vdso32/vdso32.lds \
 164                                  $(obj)/vdso32/vclock_gettime.o \
 165                                  $(obj)/vdso32/note.o \
 166                                  $(obj)/vdso32/%.o
 167         $(call if_changed,vdso)
 168
 169 #
 170 # The DSO images are built using a special linker script.
 171 #
 172 quiet_cmd_vdso = VDSO    $@
 173       cmd_vdso = $(CC) -nostdlib -o $@ \
 174                        $(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \
 175                        -Wl,-T,$(filter %.lds,$^) $(filter %.o,$^) && \
 176                  sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@'
 177
 178 VDSO_LDFLAGS = -fPIC -shared $(call cc-ldoption, -Wl$(comma)--hash-style=sysv) \
 179         $(call cc-ldoption, -Wl$(comma)--build-id) -Wl,-Bsymbolic $(LTO_CFLAGS)
 180 GCOV_PROFILE := n
 181
 182 #
 183 # Install the unstripped copies of vdso*.so.  If our toolchain supports
 184 # build-id, install .build-id links as well.
 185 #
 186 quiet_cmd_vdso_install = INSTALL $(@:install_%=%)
 187 define cmd_vdso_install
 188         cp $< "$(MODLIB)/vdso/$(@:install_%=%)"; \
 189         if readelf -n $< |grep -q 'Build ID'; then \
 190           buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \
 191           first=`echo $$buildid | cut -b-2`; \
 192           last=`echo $$buildid | cut -b3-`; \
 193           mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \
 194           ln -sf "../../$(@:install_%=%)" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \
 195         fi
 196 endef
 197
 198 vdso_img_insttargets := $(vdso_img_sodbg:%.dbg=install_%)
 199
 200 $(MODLIB)/vdso: FORCE
 201         @mkdir -p $(MODLIB)/vdso
 202
 203 $(vdso_img_insttargets): install_%: $(obj)/%.dbg $(MODLIB)/vdso FORCE
 204         $(call cmd,vdso_install)
 205
 206 PHONY += vdso_install $(vdso_img_insttargets)
 207 vdso_install: $(vdso_img_insttargets) FORCE
 208
 209 clean-files := vdso32-syscall* vdso32-sysenter* vdso32-int80* vdso64* vdso-image-*.c vdsox32.so*