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-s := note.o sigreturn.o
   9 obj-vdso-c := vgettimeofday.o
  10
  11 # Build rules
  12 targets := $(obj-vdso-s) $(obj-vdso-c) vdso.so vdso.so.dbg
  13 obj-vdso-s := $(addprefix $(obj)/, $(obj-vdso-s))
  14 obj-vdso-c := $(addprefix $(obj)/, $(obj-vdso-c))
  15 obj-vdso   := $(obj-vdso-c) $(obj-vdso-s)
  16
  17 ccflags-y := -shared -fno-common -fno-builtin -fno-stack-protector
  18 ccflags-y += -DDISABLE_BRANCH_PROFILING
  19 ccflags-y += -nostdlib -Wl,-soname=linux-vdso.so.1 \
  20                 $(call cc-ldoption, -Wl$(comma)--hash-style=sysv)
  21
  22 # Force -O2 to avoid libgcc dependencies
  23 CFLAGS_REMOVE_vgettimeofday.o = -pg -Os
  24 CFLAGS_vgettimeofday.o = -O2 -fPIC
  25 ifneq ($(cc-name),clang)
  26 CFLAGS_vgettimeofday.o += -mcmodel=tiny
  27 endif
  28
  29 # Disable gcov profiling for VDSO code
  30 GCOV_PROFILE := n
  31 KASAN_SANITIZE := n
  32 UBSAN_SANITIZE := n
  33 KCOV_INSTRUMENT := n
  34
  35 # Workaround for bare-metal (ELF) toolchains that neglect to pass -shared
  36 # down to collect2, resulting in silent corruption of the vDSO image.
  37 ccflags-y += -Wl,-shared
  38
  39 obj-y += vdso.o
  40 extra-y += vdso.lds
  41 CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
  42
  43 # Force dependency (incbin is bad)
  44 $(obj)/vdso.o : $(obj)/vdso.so
  45
  46 # Link rule for the .so file, .lds has to be first
  47 $(obj)/vdso.so.dbg: $(src)/vdso.lds $(obj-vdso)
  48         $(call if_changed,vdsold)
  49
  50 # Strip rule for the .so file
  51 $(obj)/%.so: OBJCOPYFLAGS := -S
  52 $(obj)/%.so: $(obj)/%.so.dbg FORCE
  53         $(call if_changed,objcopy)
  54
  55 # Generate VDSO offsets using helper script
  56 gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh
  57 quiet_cmd_vdsosym = VDSOSYM $@
  58 define cmd_vdsosym
  59         $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
  60 endef
  61
  62 include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE
  63         $(call if_changed,vdsosym)
  64
  65 # Assembly rules for the .S files
  66 $(obj-vdso-s): %.o: %.S FORCE
  67         $(call if_changed_dep,vdsoas)
  68
  69 $(obj-vdso-c): %.o: %.c FORCE
  70         $(call if_changed_dep,vdsocc)
  71
  72 # Actual build commands
  73 quiet_cmd_vdsold = VDSOL   $@
  74       cmd_vdsold = $(CC) $(c_flags) -Wl,-n -Wl,-T $^ -o $@
  75 quiet_cmd_vdsocc = VDSOC   $@
  76       cmd_vdsocc = ${CC} $(c_flags) -c -o $@ $<
  77 quiet_cmd_vdsoas = VDSOA   $@
  78       cmd_vdsoas = $(CC) $(a_flags) -c -o $@ $<
  79
  80 # Install commands for the unstripped file
  81 quiet_cmd_vdso_install = INSTALL $@
  82       cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@
  83
  84 vdso.so: $(obj)/vdso.so.dbg
  85         @mkdir -p $(MODLIB)/vdso
  86         $(call cmd,vdso_install)
  87
  88 vdso_install: vdso.so