arch/arm64/kernel/vdso/Makefile

   1 # SPDX-License-Identifier: GPL-2.0
   2 #
   3 # Building a vDSO image for AArch64.
   4 #
   5 # Author: Will Deacon <will.deacon@arm.com>
   6 # Heavily based on the vDSO Makefiles for other archs.
   7 #
   8
   9 # Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before
  10 # the inclusion of generic Makefile.
  11 ARCH_REL_TYPE_ABS := R_AARCH64_JUMP_SLOT|R_AARCH64_GLOB_DAT|R_AARCH64_ABS64
  12 include $(srctree)/lib/vdso/Makefile
  13
  14 obj-vdso := vgettimeofday.o note.o sigreturn.o
  15
  16 # Build rules
  17 targets := $(obj-vdso) vdso.so vdso.so.dbg
  18 obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
  19
  20 btildflags-$(CONFIG_ARM64_BTI_KERNEL) += -z force-bti
  21
  22 # -Bsymbolic has been added for consistency with arm, the compat vDSO and
  23 # potential future proofing if we end up with internal calls to the exported
  24 # routines, as x86 does (see 6f121e548f83 ("x86, vdso: Reimplement vdso.so
  25 # preparation in build-time C")).
  26 ldflags-y := -shared -soname=linux-vdso.so.1 --hash-style=sysv  \
  27              -Bsymbolic --build-id=sha1 -n $(btildflags-y) -T
  28
  29 ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18
  30 ccflags-y += -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
  31
  32 # -Wmissing-prototypes and -Wmissing-declarations are removed from
  33 # the CFLAGS of vgettimeofday.c to make possible to build the
  34 # kernel with CONFIG_WERROR enabled.
  35 CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) $(GCC_PLUGINS_CFLAGS) \
  36                                 $(CC_FLAGS_LTO) -Wmissing-prototypes -Wmissing-declarations
  37 KASAN_SANITIZE                  := n
  38 KCSAN_SANITIZE                  := n
  39 UBSAN_SANITIZE                  := n
  40 OBJECT_FILES_NON_STANDARD       := y
  41 KCOV_INSTRUMENT                 := n
  42
  43 CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny -fasynchronous-unwind-tables
  44
  45 ifneq ($(c-gettimeofday-y),)
  46   CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
  47 endif
  48
  49 # Disable gcov profiling for VDSO code
  50 GCOV_PROFILE := n
  51
  52 targets += vdso.lds
  53 CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
  54
  55 # Force dependency (incbin is bad)
  56 $(obj)/vdso.o : $(obj)/vdso.so
  57
  58 # Link rule for the .so file, .lds has to be first
  59 $(obj)/vdso.so.dbg: $(obj)/vdso.lds $(obj-vdso) FORCE
  60         $(call if_changed,vdsold_and_vdso_check)
  61
  62 # Strip rule for the .so file
  63 $(obj)/%.so: OBJCOPYFLAGS := -S
  64 $(obj)/%.so: $(obj)/%.so.dbg FORCE
  65         $(call if_changed,objcopy)
  66
  67 # Generate VDSO offsets using helper script
  68 gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh
  69 quiet_cmd_vdsosym = VDSOSYM $@
  70       cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
  71
  72 include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE
  73         $(call if_changed,vdsosym)
  74
  75 # Actual build commands
  76 quiet_cmd_vdsold_and_vdso_check = LD      $@
  77       cmd_vdsold_and_vdso_check = $(cmd_ld); $(cmd_vdso_check)
  78
  79 # Install commands for the unstripped file
  80 quiet_cmd_vdso_install = INSTALL $@
  81       cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@
  82
  83 vdso.so: $(obj)/vdso.so.dbg
  84         @mkdir -p $(MODLIB)/vdso
  85         $(call cmd,vdso_install)
  86
  87 vdso_install: vdso.so