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) $(vdso_img-y:%=vdso%.so)
  46
  47 CPPFLAGS_vdso.lds += -P -C
  48
  49 VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --no-undefined \
  50                         -z max-page-size=4096
  51
  52 $(obj)/vdso64.so.dbg: $(obj)/vdso.lds $(vobjs) FORCE
  53         $(call if_changed,vdso)
  54
  55 HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/$(SUBARCH)/include/uapi
  56 hostprogs-y                     += vdso2c
  57
  58 quiet_cmd_vdso2c = VDSO2C  $@
  59       cmd_vdso2c = $(obj)/vdso2c $< $(<:%.dbg=%) $@
  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)) $(call cc-option, -fno-stack-protector) \
  70        -fno-omit-frame-pointer -foptimize-sibling-calls \
  71        -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
  72
  73 ifdef CONFIG_RETPOLINE
  74 ifneq ($(RETPOLINE_VDSO_CFLAGS),)
  75   CFL += $(RETPOLINE_VDSO_CFLAGS)
  76 endif
  77 endif
  78
  79 $(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL)
  80
  81 #
  82 # vDSO code runs in userspace and -pg doesn't help with profiling anyway.
  83 #
  84 CFLAGS_REMOVE_vdso-note.o = -pg
  85 CFLAGS_REMOVE_vclock_gettime.o = -pg
  86 CFLAGS_REMOVE_vgetcpu.o = -pg
  87 CFLAGS_REMOVE_vvar.o = -pg
  88
  89 #
  90 # X32 processes use x32 vDSO to access 64bit kernel data.
  91 #
  92 # Build x32 vDSO image:
  93 # 1. Compile x32 vDSO as 64bit.
  94 # 2. Convert object files to x32.
  95 # 3. Build x32 VDSO image with x32 objects, which contains 64bit codes
  96 # so that it can reach 64bit address space with 64bit pointers.
  97 #
  98
  99 CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds)
 100 VDSO_LDFLAGS_vdsox32.lds = -m elf32_x86_64 -soname linux-vdso.so.1 \
 101                            -z max-page-size=4096
 102
 103 # x32-rebranded versions
 104 vobjx32s-y := $(vobjs-y:.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: $(obj)/vdsox32.lds $(vobjx32s) FORCE
 123         $(call if_changed,vdso)
 124
 125 CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds)
 126 VDSO_LDFLAGS_vdso32.lds = -m elf_i386 -soname linux-gate.so.1
 127
 128 targets += vdso32/vdso32.lds
 129 targets += vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o
 130 targets += vdso32/vclock_gettime.o
 131
 132 KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS)) -DBUILD_VDSO
 133 $(obj)/vdso32.so.dbg: KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
 134 $(obj)/vdso32.so.dbg: asflags-$(CONFIG_X86_64) += -m32
 135
 136 KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
 137 KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
 138 KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
 139 KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
 140 KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32))
 141 KBUILD_CFLAGS_32 := $(filter-out $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS_32))
 142 KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
 143 KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector)
 144 KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)
 145 KBUILD_CFLAGS_32 += -fno-omit-frame-pointer
 146 KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING
 147
 148 ifdef CONFIG_RETPOLINE
 149 ifneq ($(RETPOLINE_VDSO_CFLAGS),)
 150   KBUILD_CFLAGS_32 += $(RETPOLINE_VDSO_CFLAGS)
 151 endif
 152 endif
 153
 154 $(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
 155
 156 $(obj)/vdso32.so.dbg: FORCE \
 157                       $(obj)/vdso32/vdso32.lds \
 158                       $(obj)/vdso32/vclock_gettime.o \
 159                       $(obj)/vdso32/note.o \
 160                       $(obj)/vdso32/system_call.o \
 161                       $(obj)/vdso32/sigreturn.o
 162         $(call if_changed,vdso)
 163
 164 #
 165 # The DSO images are built using a special linker script.
 166 #
 167 quiet_cmd_vdso = VDSO    $@
 168       cmd_vdso = $(LD) -nostdlib -o $@ \
 169                        $(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \
 170                        -T $(filter %.lds,$^) $(filter %.o,$^) && \
 171                  sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@'
 172
 173 VDSO_LDFLAGS = -shared $(call ld-option, --hash-style=both) \
 174         $(call ld-option, --build-id) $(call ld-option, --eh-frame-hdr) \
 175         -Bsymbolic
 176 GCOV_PROFILE := n
 177
 178 #
 179 # Install the unstripped copies of vdso*.so.  If our toolchain supports
 180 # build-id, install .build-id links as well.
 181 #
 182 quiet_cmd_vdso_install = INSTALL $(@:install_%=%)
 183 define cmd_vdso_install
 184         cp $< "$(MODLIB)/vdso/$(@:install_%=%)"; \
 185         if readelf -n $< |grep -q 'Build ID'; then \
 186           buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \
 187           first=`echo $$buildid | cut -b-2`; \
 188           last=`echo $$buildid | cut -b3-`; \
 189           mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \
 190           ln -sf "../../$(@:install_%=%)" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \
 191         fi
 192 endef
 193
 194 vdso_img_insttargets := $(vdso_img_sodbg:%.dbg=install_%)
 195
 196 $(MODLIB)/vdso: FORCE
 197         @mkdir -p $(MODLIB)/vdso
 198
 199 $(vdso_img_insttargets): install_%: $(obj)/%.dbg $(MODLIB)/vdso
 200         $(call cmd,vdso_install)
 201
 202 PHONY += vdso_install $(vdso_img_insttargets)
 203 vdso_install: $(vdso_img_insttargets)
 204
 205 clean-files := vdso32.so vdso32.so.dbg vdso64* vdso-image-*.c vdsox32.so*