arch/arm64/kernel/vdso32/Makefile

   1 #
   2 # Building a vDSO image for AArch32.
   3 #
   4 # Author: Kevin Brodsky <kevin.brodsky@arm.com>
   5 # A mix between the arm64 and arm vDSO Makefiles.
   6
   7 ifeq ($(cc-name),clang)
   8   CC_ARM32 := $(cc-name) $(CLANG_TARGET_ARM32) -no-integrated-as
   9 else
  10   CC_ARM32 := $(CROSS_COMPILE_ARM32)$(cc-name)
  11 endif
  12
  13 # Same as cc-*option, but using CC_ARM32 instead of CC
  14 cc32-option = $(call try-run,\
  15         $(CC_ARM32) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2))
  16 cc32-disable-warning = $(call try-run,\
  17         $(CC_ARM32) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
  18 cc32-ldoption = $(call try-run,\
  19         $(CC_ARM32) $(1) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2))
  20
  21 # We cannot use the global flags to compile the vDSO files, the main reason
  22 # being that the 32-bit compiler may be older than the main (64-bit) compiler
  23 # and therefore may not understand flags set using $(cc-option ...). Besides,
  24 # arch-specific options should be taken from the arm Makefile instead of the
  25 # arm64 one.
  26 # As a result we set our own flags here.
  27
  28 # From top-level Makefile
  29 # NOSTDINC_FLAGS
  30 VDSO_CPPFLAGS := -nostdinc -isystem $(shell $(CC_ARM32) -print-file-name=include)
  31 VDSO_CPPFLAGS += $(LINUXINCLUDE)
  32 VDSO_CPPFLAGS += $(KBUILD_CPPFLAGS)
  33
  34 # Common C and assembly flags
  35 # From top-level Makefile
  36 VDSO_CAFLAGS := $(VDSO_CPPFLAGS)
  37 VDSO_CAFLAGS += $(call cc32-option,-fno-PIE)
  38 ifdef CONFIG_DEBUG_INFO
  39 VDSO_CAFLAGS += -g
  40 endif
  41 ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC_ARM32)), y)
  42 VDSO_CAFLAGS += -DCC_HAVE_ASM_GOTO
  43 endif
  44
  45 # From arm Makefile
  46 VDSO_CAFLAGS += $(call cc32-option,-fno-dwarf2-cfi-asm)
  47 VDSO_CAFLAGS += -mabi=aapcs-linux -mfloat-abi=soft
  48 ifeq ($(CONFIG_CPU_BIG_ENDIAN), y)
  49 VDSO_CAFLAGS += -mbig-endian
  50 else
  51 VDSO_CAFLAGS += -mlittle-endian
  52 endif
  53
  54 # From arm vDSO Makefile
  55 VDSO_CAFLAGS += -fPIC -fno-builtin -fno-stack-protector
  56 VDSO_CAFLAGS += -DDISABLE_BRANCH_PROFILING
  57
  58 # Try to compile for ARMv8. If the compiler is too old and doesn't support it,
  59 # fall back to v7. There is no easy way to check for what architecture the code
  60 # is being compiled, so define a macro specifying that (see arch/arm/Makefile).
  61 VDSO_CAFLAGS += $(call cc32-option,-march=armv8-a -D__LINUX_ARM_ARCH__=8,\
  62                                    -march=armv7-a -D__LINUX_ARM_ARCH__=7)
  63
  64 VDSO_CFLAGS := $(VDSO_CAFLAGS)
  65 # KBUILD_CFLAGS from top-level Makefile
  66 VDSO_CFLAGS += -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
  67                -fno-strict-aliasing -fno-common \
  68                -Werror-implicit-function-declaration \
  69                -Wno-format-security \
  70                -std=gnu89
  71 VDSO_CFLAGS  += -O2
  72 # Some useful compiler-dependent flags from top-level Makefile
  73 VDSO_CFLAGS += $(call cc32-option,-Wdeclaration-after-statement,)
  74 VDSO_CFLAGS += $(call cc32-option,-Wno-pointer-sign)
  75 VDSO_CFLAGS += $(call cc32-option,-fno-strict-overflow)
  76 VDSO_CFLAGS += $(call cc32-option,-Werror=strict-prototypes)
  77 VDSO_CFLAGS += $(call cc32-option,-Werror=date-time)
  78 VDSO_CFLAGS += $(call cc32-option,-Werror=incompatible-pointer-types)
  79
  80 # The 32-bit compiler does not provide 128-bit integers, which are used in
  81 # some headers that are indirectly included from the vDSO code.
  82 # This hack makes the compiler happy and should trigger a warning/error if
  83 # variables of such type are referenced.
  84 VDSO_CFLAGS += -D__uint128_t='void*'
  85 # Silence some warnings coming from headers that operate on long's
  86 # (on GCC 4.8 or older, there is unfortunately no way to silence this warning)
  87 VDSO_CFLAGS += $(call cc32-disable-warning,shift-count-overflow)
  88 VDSO_CFLAGS += -Wno-int-to-pointer-cast
  89
  90 VDSO_AFLAGS := $(VDSO_CAFLAGS)
  91 VDSO_AFLAGS += -D__ASSEMBLY__
  92
  93 VDSO_LDFLAGS := $(VDSO_CPPFLAGS)
  94 # From arm vDSO Makefile
  95 VDSO_LDFLAGS += -Wl,-Bsymbolic -Wl,--no-undefined -Wl,-soname=linux-vdso.so.1
  96 VDSO_LDFLAGS += -Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096
  97 VDSO_LDFLAGS += -nostdlib -shared -mfloat-abi=soft
  98 VDSO_LDFLAGS += $(call cc32-ldoption,-Wl$(comma)--hash-style=sysv)
  99 VDSO_LDFLAGS += $(call cc32-ldoption,-Wl$(comma)--build-id)
 100 VDSO_LDFLAGS += $(call cc32-ldoption,-fuse-ld=bfd)
 101
 102
 103 # Borrow vdsomunge.c from the arm vDSO
 104 # We have to use a relative path because scripts/Makefile.host prefixes
 105 # $(hostprogs-y) with $(obj)
 106 munge := ../../../arm/vdso/vdsomunge
 107 hostprogs-y := $(munge)
 108
 109 c-obj-vdso := vgettimeofday.o
 110 asm-obj-vdso := sigreturn.o
 111
 112 # Build rules
 113 targets := $(c-obj-vdso) $(asm-obj-vdso) vdso.so vdso.so.dbg vdso.so.raw
 114 c-obj-vdso := $(addprefix $(obj)/, $(c-obj-vdso))
 115 asm-obj-vdso := $(addprefix $(obj)/, $(asm-obj-vdso))
 116 obj-vdso := $(c-obj-vdso) $(asm-obj-vdso)
 117
 118 obj-y += vdso.o
 119 extra-y += vdso.lds
 120 CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
 121
 122 # Force dependency (vdso.s includes vdso.so through incbin)
 123 $(obj)/vdso.o: $(obj)/vdso.so
 124
 125 include/generated/vdso32-offsets.h: $(obj)/vdso.so.dbg FORCE
 126         $(call if_changed,vdsosym)
 127
 128 # Strip rule for vdso.so
 129 $(obj)/vdso.so: OBJCOPYFLAGS := -S
 130 $(obj)/vdso.so: $(obj)/vdso.so.dbg FORCE
 131         $(call if_changed,objcopy)
 132
 133 $(obj)/vdso.so.dbg: $(obj)/vdso.so.raw $(obj)/$(munge) FORCE
 134         $(call if_changed,vdsomunge)
 135
 136 # Link rule for the .so file, .lds has to be first
 137 $(obj)/vdso.so.raw: $(src)/vdso.lds $(obj-vdso) FORCE
 138         $(call if_changed,vdsold)
 139
 140 # Compilation rules for the vDSO sources
 141 $(filter-out vgettimeofday.o, $(c-obj-vdso)): %.o: %.c FORCE
 142         $(call if_changed_dep,vdsocc)
 143 $(asm-obj-vdso): %.o: %.S FORCE
 144         $(call if_changed_dep,vdsoas)
 145
 146 # Actual build commands
 147 quiet_cmd_vdsold = VDSOL32   $@
 148       cmd_vdsold = $(CC_ARM32) -Wp,-MD,$(depfile) $(VDSO_LDFLAGS) \
 149                    -Wl,-T $(filter %.lds,$^) $(filter %.o,$^) -o $@
 150 quiet_cmd_vdsocc = VDSOC32   $@
 151       cmd_vdsocc = $(CC_ARM32) -Wp,-MD,$(depfile) $(VDSO_CFLAGS) -c -o $@ $<
 152 quiet_cmd_vdsoas = VDSOA32   $@
 153       cmd_vdsoas = $(CC_ARM32) -Wp,-MD,$(depfile) $(VDSO_AFLAGS) -c -o $@ $<
 154
 155 quiet_cmd_vdsomunge = MUNGE   $@
 156       cmd_vdsomunge = $(obj)/$(munge) $< $@
 157
 158 # Generate vDSO offsets using helper script (borrowed from the 64-bit vDSO)
 159 gen-vdsosym := $(srctree)/$(src)/../vdso/gen_vdso_offsets.sh
 160 quiet_cmd_vdsosym = VDSOSYM $@
 161 # The AArch64 nm should be able to read an AArch32 binary
 162       cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
 163
 164 # Install commands for the unstripped file
 165 quiet_cmd_vdso_install = INSTALL $@
 166       cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/vdso32.so
 167
 168 vdso.so: $(obj)/vdso.so.dbg
 169         @mkdir -p $(MODLIB)/vdso
 170         $(call cmd,vdso_install)
 171
 172 vdso_install: vdso.so