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 -nostdlib -soname=linux-vdso.so.1 --hash-style=sysv        \
  27              -Bsymbolic $(call ld-option, --no-eh-frame-hdr) --build-id=sha1 -n \
  28              $(btildflags-y) -T
  29
  30 ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18
  31 ccflags-y += -DDISABLE_BRANCH_PROFILING
  32
  33 CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) $(GCC_PLUGINS_CFLAGS)
  34 KASAN_SANITIZE                  := n
  35 UBSAN_SANITIZE                  := n
  36 OBJECT_FILES_NON_STANDARD       := y
  37 KCOV_INSTRUMENT                 := n
  38
  39 CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny -fasynchronous-unwind-tables
  40
  41 ifneq ($(c-gettimeofday-y),)
  42   CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
  43 endif
  44
  45 # Clang versions less than 8 do not support -mcmodel=tiny
  46 ifeq ($(CONFIG_CC_IS_CLANG), y)
  47   ifeq ($(shell test $(CONFIG_CLANG_VERSION) -lt 80000; echo $$?),0)
  48     CFLAGS_REMOVE_vgettimeofday.o += -mcmodel=tiny
  49   endif
  50 endif
  51
  52 # Disable gcov profiling for VDSO code
  53 GCOV_PROFILE := n
  54
  55 obj-y += vdso.o
  56 targets += vdso.lds
  57 CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
  58
  59 # Force dependency (incbin is bad)
  60 $(obj)/vdso.o : $(obj)/vdso.so
  61
  62 # Link rule for the .so file, .lds has to be first
  63 $(obj)/vdso.so.dbg: $(obj)/vdso.lds $(obj-vdso) FORCE
  64         $(call if_changed,vdsold_and_vdso_check)
  65
  66 # Strip rule for the .so file
  67 $(obj)/%.so: OBJCOPYFLAGS := -S
  68 $(obj)/%.so: $(obj)/%.so.dbg FORCE
  69         $(call if_changed,objcopy)
  70
  71 # Generate VDSO offsets using helper script
  72 gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh
  73 quiet_cmd_vdsosym = VDSOSYM $@
  74       cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
  75
  76 include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE
  77         $(call if_changed,vdsosym)
  78
  79 # Actual build commands
  80 quiet_cmd_vdsold_and_vdso_check = LD      $@
  81       cmd_vdsold_and_vdso_check = $(cmd_ld); $(cmd_vdso_check)
  82
  83 # Install commands for the unstripped file
  84 quiet_cmd_vdso_install = INSTALL $@
  85       cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@
  86
  87 vdso.so: $(obj)/vdso.so.dbg
  88         @mkdir -p $(MODLIB)/vdso
  89         $(call cmd,vdso_install)
  90
  91 vdso_install: vdso.so