arch/arm64/kernel/vdso/Makefile

   1 #
   2 # Building a vDSO image for AArch64.
   3 #
   4 # Author: Will Deacon <will.deacon@arm.com>
   5 # Heavily based on the vDSO Makefiles for other archs.
   6 #
   7
   8 obj-vdso := gettimeofday.o note.o sigreturn.o
   9
  10 # Build rules
  11 targets := $(obj-vdso) vdso.so vdso.so.dbg
  12 obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
  13
  14 ccflags-y := -shared -fno-common -fno-builtin
  15 ccflags-y += -nostdlib -Wl,-soname=linux-vdso.so.1 \
  16                 $(call cc-ldoption, -Wl$(comma)--hash-style=sysv)
  17
  18 # Disable gcov profiling for VDSO code
  19 GCOV_PROFILE := n
  20
  21 # Workaround for bare-metal (ELF) toolchains that neglect to pass -shared
  22 # down to collect2, resulting in silent corruption of the vDSO image.
  23 ccflags-y += -Wl,-shared
  24
  25 obj-y += vdso.o
  26 extra-y += vdso.lds
  27 CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
  28
  29 # Force dependency (incbin is bad)
  30 $(obj)/vdso.o : $(obj)/vdso.so
  31
  32 # Link rule for the .so file, .lds has to be first
  33 $(obj)/vdso.so.dbg: $(src)/vdso.lds $(obj-vdso)
  34         $(call if_changed,vdsold)
  35
  36 # Strip rule for the .so file
  37 $(obj)/%.so: OBJCOPYFLAGS := -S
  38 $(obj)/%.so: $(obj)/%.so.dbg FORCE
  39         $(call if_changed,objcopy)
  40
  41 # Generate VDSO offsets using helper script
  42 gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh
  43 quiet_cmd_vdsosym = VDSOSYM $@
  44 define cmd_vdsosym
  45         $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
  46 endef
  47
  48 include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE
  49         $(call if_changed,vdsosym)
  50
  51 # Assembly rules for the .S files
  52 $(obj-vdso): %.o: %.S FORCE
  53         $(call if_changed_dep,vdsoas)
  54
  55 # Actual build commands
  56 quiet_cmd_vdsold = VDSOL   $@
  57       cmd_vdsold = $(CC) $(c_flags) -Wl,-n -Wl,-T $^ -o $@
  58 quiet_cmd_vdsoas = VDSOA   $@
  59       cmd_vdsoas = $(CC) $(a_flags) -c -o $@ $<
  60
  61 # Install commands for the unstripped file
  62 quiet_cmd_vdso_install = INSTALL $@
  63       cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@
  64
  65 vdso.so: $(obj)/vdso.so.dbg
  66         @mkdir -p $(MODLIB)/vdso
  67         $(call cmd,vdso_install)
  68
  69 vdso_install: vdso.so