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 # Include the generic Makefile to check the built vdso.
  10 include $(srctree)/lib/vdso/Makefile
  11
  12 obj-vdso := vgettimeofday.o note.o sigreturn.o vgetrandom.o vgetrandom-chacha.o
  13
  14 # Build rules
  15 targets := $(obj-vdso) vdso.so vdso.so.dbg
  16 obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
  17
  18 btildflags-$(CONFIG_ARM64_BTI_KERNEL) += -z force-bti
  19
  20 # -Bsymbolic has been added for consistency with arm, the compat vDSO and
  21 # potential future proofing if we end up with internal calls to the exported
  22 # routines, as x86 does (see 6f121e548f83 ("x86, vdso: Reimplement vdso.so
  23 # preparation in build-time C")).
  24 ldflags-y := -shared -soname=linux-vdso.so.1 \
  25              -Bsymbolic --build-id=sha1 -n $(btildflags-y)
  26
  27 ifdef CONFIG_LD_ORPHAN_WARN
  28   ldflags-y += --orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL)
  29 endif
  30
  31 ldflags-y += -T
  32
  33 ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18
  34 ccflags-y += -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
  35
  36 # -Wmissing-prototypes and -Wmissing-declarations are removed from
  37 # the CFLAGS to make possible to build the kernel with CONFIG_WERROR enabled.
  38 CC_FLAGS_REMOVE_VDSO := $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) \
  39                         $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) \
  40                         $(CC_FLAGS_LTO) $(CC_FLAGS_CFI) \
  41                         -Wmissing-prototypes -Wmissing-declarations
  42
  43 CC_FLAGS_ADD_VDSO := -O2 -mcmodel=tiny -fasynchronous-unwind-tables
  44
  45 CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_REMOVE_VDSO)
  46 CFLAGS_REMOVE_vgetrandom.o = $(CC_FLAGS_REMOVE_VDSO)
  47
  48 CFLAGS_vgettimeofday.o = $(CC_FLAGS_ADD_VDSO)
  49 CFLAGS_vgetrandom.o = $(CC_FLAGS_ADD_VDSO)
  50
  51 ifneq ($(c-gettimeofday-y),)
  52   CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
  53 endif
  54
  55 ifneq ($(c-getrandom-y),)
  56   CFLAGS_vgetrandom.o += -include $(c-getrandom-y)
  57 endif
  58
  59 targets += vdso.lds
  60 CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
  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 := $(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)