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linux/arch/mips/vdso/Makefile
Paul Burton 8919975b61
MIPS: VDSO: Fix build for binutils < 2.25 
Versions of binutils prior to 2.25 are unable to link our VDSO due to an
unsupported R_MIPS_PC32 relocation generated by the ".word _start - ."
line of the inline asm in get_vdso_base(). As such, the intent is that
when building with binutils older than 2.25 we don't build code for
gettimeofday() & friends in the VDSO that rely upon get_vdso_base().

Commit 24640f233b46 ("mips: Add support for generic vDSO") converted us
to using generic VDSO infrastructure, and as part of that the
gettimeofday() functionality moved to a new vgettimeofday.c file. The
check for binutils < 2.25 wasn't updated to handle this new filename,
and so it continues trying to remove the old unused filename from the
build. The end result is that we try to include the gettimeofday() code
in builds that will fail to link.

Fix this by updating the binutils < 2.25 case to remove vgettimeofday.c
from obj-vdso-y, rather than gettimeofday.c.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Fixes: 24640f233b46 ("mips: Add support for generic vDSO")
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: linux-mips@vger.kernel.org
2019-10-02 14:07:32 -07:00

216 lines
6.3 KiB
Makefile
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# SPDX-License-Identifier: GPL-2.0
# Objects to go into the VDSO.
# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before
# the inclusion of generic Makefile.
ARCH_REL_TYPE_ABS := R_MIPS_JUMP_SLOT|R_MIPS_GLOB_DAT
include $(srctree)/lib/vdso/Makefile
obj-vdso-y := elf.o vgettimeofday.o sigreturn.o
# Common compiler flags between ABIs.
ccflags-vdso := \
$(filter -I%,$(KBUILD_CFLAGS)) \
$(filter -E%,$(KBUILD_CFLAGS)) \
$(filter -mmicromips,$(KBUILD_CFLAGS)) \
$(filter -march=%,$(KBUILD_CFLAGS)) \
$(filter -m%-float,$(KBUILD_CFLAGS)) \
-D__VDSO__
ifdef CONFIG_CC_IS_CLANG
ccflags-vdso += $(filter --target=%,$(KBUILD_CFLAGS))
endif
#
# The -fno-jump-tables flag only prevents the compiler from generating
# jump tables but does not prevent the compiler from emitting absolute
# offsets.
cflags-vdso := $(ccflags-vdso) \
$(filter -W%,$(filter-out -Wa$(comma)%,$(KBUILD_CFLAGS))) \
-O3 -g -fPIC -fno-strict-aliasing -fno-common -fno-builtin -G 0 \
-fno-stack-protector -fno-jump-tables -DDISABLE_BRANCH_PROFILING \
$(call cc-option, -fno-asynchronous-unwind-tables) \
$(call cc-option, -fno-stack-protector)
aflags-vdso := $(ccflags-vdso) \
-D__ASSEMBLY__ -Wa,-gdwarf-2
ifneq ($(c-gettimeofday-y),)
CFLAGS_vgettimeofday.o = -include $(c-gettimeofday-y)
# config-n32-o32-env.c prepares the environment to build a 32bit vDSO
# library on a 64bit kernel.
# Note: Needs to be included before than the generic library.
CFLAGS_vgettimeofday-o32.o = -include $(srctree)/$(src)/config-n32-o32-env.c -include $(c-gettimeofday-y)
CFLAGS_vgettimeofday-n32.o = -include $(srctree)/$(src)/config-n32-o32-env.c -include $(c-gettimeofday-y)
endif
CFLAGS_REMOVE_vgettimeofday.o = -pg
#
# For the pre-R6 code in arch/mips/vdso/vdso.h for locating
# the base address of VDSO, the linker will emit a R_MIPS_PC32
# relocation in binutils > 2.25 but it will fail with older versions
# because that relocation is not supported for that symbol. As a result
# of which we are forced to disable the VDSO symbols when building
# with < 2.25 binutils on pre-R6 kernels. For more references on why we
# can't use other methods to get the base address of VDSO please refer to
# the comments on that file.
#
ifndef CONFIG_CPU_MIPSR6
ifeq ($(call ld-ifversion, -lt, 225000000, y),y)
$(warning MIPS VDSO requires binutils >= 2.25)
obj-vdso-y := $(filter-out vgettimeofday.o, $(obj-vdso-y))
ccflags-vdso += -DDISABLE_MIPS_VDSO
endif
endif
# VDSO linker flags.
VDSO_LDFLAGS := \
-Wl,-Bsymbolic -Wl,--no-undefined -Wl,-soname=linux-vdso.so.1 \
$(addprefix -Wl$(comma),$(filter -E%,$(KBUILD_CFLAGS))) \
-nostdlib -shared -Wl,--hash-style=sysv -Wl,--build-id
CFLAGS_REMOVE_vdso.o = -pg
GCOV_PROFILE := n
UBSAN_SANITIZE := n
#
# Shared build commands.
#
quiet_cmd_vdsold_and_vdso_check = LD $@
cmd_vdsold_and_vdso_check = $(cmd_vdsold); $(cmd_vdso_check)
quiet_cmd_vdsold = VDSO $@
cmd_vdsold = $(CC) $(c_flags) $(VDSO_LDFLAGS) \
-Wl,-T $(filter %.lds,$^) $(filter %.o,$^) -o $@
quiet_cmd_vdsoas_o_S = AS $@
cmd_vdsoas_o_S = $(CC) $(a_flags) -c -o $@ $<
# Strip rule for the raw .so files
$(obj)/%.so.raw: OBJCOPYFLAGS := -S
$(obj)/%.so.raw: $(obj)/%.so.dbg.raw FORCE
$(call if_changed,objcopy)
hostprogs-y := genvdso
quiet_cmd_genvdso = GENVDSO $@
define cmd_genvdso
$(foreach file,$(filter %.raw,$^),cp $(file) $(file:%.raw=%) &&) \
$(obj)/genvdso $(<:%.raw=%) $(<:%.dbg.raw=%) $@ $(VDSO_NAME)
endef
#
# Build native VDSO.
#
native-abi := $(filter -mabi=%,$(KBUILD_CFLAGS))
targets += $(obj-vdso-y)
targets += vdso.lds
targets += vdso.so.dbg.raw vdso.so.raw
targets += vdso.so.dbg vdso.so
targets += vdso-image.c
obj-vdso := $(obj-vdso-y:%.o=$(obj)/%.o)
$(obj-vdso): KBUILD_CFLAGS := $(cflags-vdso) $(native-abi)
$(obj-vdso): KBUILD_AFLAGS := $(aflags-vdso) $(native-abi)
$(obj)/vdso.lds: KBUILD_CPPFLAGS := $(ccflags-vdso) $(native-abi)
$(obj)/vdso.so.dbg.raw: $(obj)/vdso.lds $(obj-vdso) FORCE
$(call if_changed,vdsold_and_vdso_check)
$(obj)/vdso-image.c: $(obj)/vdso.so.dbg.raw $(obj)/vdso.so.raw \
$(obj)/genvdso FORCE
$(call if_changed,genvdso)
obj-y += vdso-image.o
#
# Build O32 VDSO.
#
# Define these outside the ifdef to ensure they are picked up by clean.
targets += $(obj-vdso-y:%.o=%-o32.o)
targets += vdso-o32.lds
targets += vdso-o32.so.dbg.raw vdso-o32.so.raw
targets += vdso-o32.so.dbg vdso-o32.so
targets += vdso-o32-image.c
ifdef CONFIG_MIPS32_O32
obj-vdso-o32 := $(obj-vdso-y:%.o=$(obj)/%-o32.o)
$(obj-vdso-o32): KBUILD_CFLAGS := $(cflags-vdso) -mabi=32
$(obj-vdso-o32): KBUILD_AFLAGS := $(aflags-vdso) -mabi=32
$(obj)/%-o32.o: $(src)/%.S FORCE
$(call if_changed_dep,vdsoas_o_S)
$(obj)/%-o32.o: $(src)/%.c FORCE
$(call cmd,force_checksrc)
$(call if_changed_rule,cc_o_c)
$(obj)/vdso-o32.lds: KBUILD_CPPFLAGS := $(ccflags-vdso) -mabi=32
$(obj)/vdso-o32.lds: $(src)/vdso.lds.S FORCE
$(call if_changed_dep,cpp_lds_S)
$(obj)/vdso-o32.so.dbg.raw: $(obj)/vdso-o32.lds $(obj-vdso-o32) FORCE
$(call if_changed,vdsold_and_vdso_check)
$(obj)/vdso-o32-image.c: VDSO_NAME := o32
$(obj)/vdso-o32-image.c: $(obj)/vdso-o32.so.dbg.raw $(obj)/vdso-o32.so.raw \
$(obj)/genvdso FORCE
$(call if_changed,genvdso)
obj-y += vdso-o32-image.o
endif
#
# Build N32 VDSO.
#
targets += $(obj-vdso-y:%.o=%-n32.o)
targets += vdso-n32.lds
targets += vdso-n32.so.dbg.raw vdso-n32.so.raw
targets += vdso-n32.so.dbg vdso-n32.so
targets += vdso-n32-image.c
ifdef CONFIG_MIPS32_N32
obj-vdso-n32 := $(obj-vdso-y:%.o=$(obj)/%-n32.o)
$(obj-vdso-n32): KBUILD_CFLAGS := $(cflags-vdso) -mabi=n32
$(obj-vdso-n32): KBUILD_AFLAGS := $(aflags-vdso) -mabi=n32
$(obj)/%-n32.o: $(src)/%.S FORCE
$(call if_changed_dep,vdsoas_o_S)
$(obj)/%-n32.o: $(src)/%.c FORCE
$(call cmd,force_checksrc)
$(call if_changed_rule,cc_o_c)
$(obj)/vdso-n32.lds: KBUILD_CPPFLAGS := $(ccflags-vdso) -mabi=n32
$(obj)/vdso-n32.lds: $(src)/vdso.lds.S FORCE
$(call if_changed_dep,cpp_lds_S)
$(obj)/vdso-n32.so.dbg.raw: $(obj)/vdso-n32.lds $(obj-vdso-n32) FORCE
$(call if_changed,vdsold_and_vdso_check)
$(obj)/vdso-n32-image.c: VDSO_NAME := n32
$(obj)/vdso-n32-image.c: $(obj)/vdso-n32.so.dbg.raw $(obj)/vdso-n32.so.raw \
$(obj)/genvdso FORCE
$(call if_changed,genvdso)
obj-y += vdso-n32-image.o
endif
# FIXME: Need install rule for debug.
# Needs to deal with dependency for generation of dbg by cmd_genvdso...
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