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0648e50e54
The MIPS VDSO build currently doesn't provide the -msoft-float flag to
the compiler as the kernel proper does. This results in an attempt to
use the compiler's default floating point configuration, which can be
problematic in cases where this is incompatible with the target CPU's
-march= flag. For example decstation_defconfig fails to build using
toolchains in which gcc was configured --with-fp-32=xx with the
following error:
LDS arch/mips/vdso/vdso.lds
cc1: error: '-march=r3000' requires '-mfp32'
make[2]: *** [scripts/Makefile.build:379: arch/mips/vdso/vdso.lds] Error 1
The kernel proper avoids this error because we build with the
-msoft-float compiler flag, rather than using the compiler's default.
Pass this flag through to the VDSO build so that it too becomes agnostic
to the toolchain's floating point configuration.
Note that this is filtered out from KBUILD_CFLAGS rather than simply
always using -msoft-float such that if we switch the kernel to use
-mno-float in the future the VDSO will automatically inherit the change.
The VDSO doesn't actually include any floating point code, and its
.MIPS.abiflags section is already manually generated to specify that
it's compatible with any floating point ABI. As such this change should
have no effect on the resulting VDSO, apart from fixing the build
failure for affected toolchains.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Reported-by: Kevin Hilman <khilman@baylibre.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Kevin Hilman <khilman@baylibre.com>
References: https://lore.kernel.org/linux-mips/1477843551-21813-1-git-send-email-linux@roeck-us.net/
References: https://kernelci.org/build/id/5c4e4ae059b5142a249ad004/logs/
Fixes: ebb5e78cc6 ("MIPS: Initial implementation of a VDSO")
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@vger.kernel.org
Cc: stable@vger.kernel.org # v4.4+
191 lines
5.3 KiB
Makefile
191 lines
5.3 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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# Objects to go into the VDSO.
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obj-vdso-y := elf.o gettimeofday.o sigreturn.o
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# Common compiler flags between ABIs.
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ccflags-vdso := \
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$(filter -I%,$(KBUILD_CFLAGS)) \
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$(filter -E%,$(KBUILD_CFLAGS)) \
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$(filter -mmicromips,$(KBUILD_CFLAGS)) \
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$(filter -march=%,$(KBUILD_CFLAGS)) \
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$(filter -m%-float,$(KBUILD_CFLAGS)) \
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-D__VDSO__
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ifdef CONFIG_CC_IS_CLANG
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ccflags-vdso += $(filter --target=%,$(KBUILD_CFLAGS))
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endif
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cflags-vdso := $(ccflags-vdso) \
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$(filter -W%,$(filter-out -Wa$(comma)%,$(KBUILD_CFLAGS))) \
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-O2 -g -fPIC -fno-strict-aliasing -fno-common -fno-builtin -G 0 \
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-DDISABLE_BRANCH_PROFILING \
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$(call cc-option, -fno-asynchronous-unwind-tables) \
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$(call cc-option, -fno-stack-protector)
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aflags-vdso := $(ccflags-vdso) \
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-D__ASSEMBLY__ -Wa,-gdwarf-2
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#
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# For the pre-R6 code in arch/mips/vdso/vdso.h for locating
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# the base address of VDSO, the linker will emit a R_MIPS_PC32
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# relocation in binutils > 2.25 but it will fail with older versions
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# because that relocation is not supported for that symbol. As a result
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# of which we are forced to disable the VDSO symbols when building
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# with < 2.25 binutils on pre-R6 kernels. For more references on why we
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# can't use other methods to get the base address of VDSO please refer to
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# the comments on that file.
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#
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ifndef CONFIG_CPU_MIPSR6
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ifeq ($(call ld-ifversion, -lt, 225000000, y),y)
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$(warning MIPS VDSO requires binutils >= 2.25)
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obj-vdso-y := $(filter-out gettimeofday.o, $(obj-vdso-y))
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ccflags-vdso += -DDISABLE_MIPS_VDSO
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endif
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endif
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# VDSO linker flags.
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VDSO_LDFLAGS := \
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-Wl,-Bsymbolic -Wl,--no-undefined -Wl,-soname=linux-vdso.so.1 \
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$(addprefix -Wl$(comma),$(filter -E%,$(KBUILD_CFLAGS))) \
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-nostdlib -shared \
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$(call cc-ldoption, -Wl$(comma)--hash-style=sysv) \
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$(call cc-ldoption, -Wl$(comma)--build-id)
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GCOV_PROFILE := n
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UBSAN_SANITIZE := n
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#
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# Shared build commands.
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#
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quiet_cmd_vdsold = VDSO $@
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cmd_vdsold = $(CC) $(c_flags) $(VDSO_LDFLAGS) \
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-Wl,-T $(filter %.lds,$^) $(filter %.o,$^) -o $@
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quiet_cmd_vdsoas_o_S = AS $@
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cmd_vdsoas_o_S = $(CC) $(a_flags) -c -o $@ $<
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# Strip rule for the raw .so files
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$(obj)/%.so.raw: OBJCOPYFLAGS := -S
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$(obj)/%.so.raw: $(obj)/%.so.dbg.raw FORCE
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$(call if_changed,objcopy)
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hostprogs-y := genvdso
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quiet_cmd_genvdso = GENVDSO $@
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define cmd_genvdso
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$(foreach file,$(filter %.raw,$^),cp $(file) $(file:%.raw=%) &&) \
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$(obj)/genvdso $(<:%.raw=%) $(<:%.dbg.raw=%) $@ $(VDSO_NAME)
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endef
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#
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# Build native VDSO.
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#
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native-abi := $(filter -mabi=%,$(KBUILD_CFLAGS))
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targets += $(obj-vdso-y)
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targets += vdso.lds
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targets += vdso.so.dbg.raw vdso.so.raw
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targets += vdso.so.dbg vdso.so
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targets += vdso-image.c
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obj-vdso := $(obj-vdso-y:%.o=$(obj)/%.o)
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$(obj-vdso): KBUILD_CFLAGS := $(cflags-vdso) $(native-abi)
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$(obj-vdso): KBUILD_AFLAGS := $(aflags-vdso) $(native-abi)
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$(obj)/vdso.lds: KBUILD_CPPFLAGS := $(ccflags-vdso) $(native-abi)
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$(obj)/vdso.so.dbg.raw: $(obj)/vdso.lds $(obj-vdso) FORCE
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$(call if_changed,vdsold)
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$(obj)/vdso-image.c: $(obj)/vdso.so.dbg.raw $(obj)/vdso.so.raw \
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$(obj)/genvdso FORCE
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$(call if_changed,genvdso)
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obj-y += vdso-image.o
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#
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# Build O32 VDSO.
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#
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# Define these outside the ifdef to ensure they are picked up by clean.
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targets += $(obj-vdso-y:%.o=%-o32.o)
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targets += vdso-o32.lds
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targets += vdso-o32.so.dbg.raw vdso-o32.so.raw
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targets += vdso-o32.so.dbg vdso-o32.so
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targets += vdso-o32-image.c
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ifdef CONFIG_MIPS32_O32
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obj-vdso-o32 := $(obj-vdso-y:%.o=$(obj)/%-o32.o)
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$(obj-vdso-o32): KBUILD_CFLAGS := $(cflags-vdso) -mabi=32
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$(obj-vdso-o32): KBUILD_AFLAGS := $(aflags-vdso) -mabi=32
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$(obj)/%-o32.o: $(src)/%.S FORCE
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$(call if_changed_dep,vdsoas_o_S)
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$(obj)/%-o32.o: $(src)/%.c FORCE
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$(call cmd,force_checksrc)
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$(call if_changed_rule,cc_o_c)
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$(obj)/vdso-o32.lds: KBUILD_CPPFLAGS := -mabi=32
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$(obj)/vdso-o32.lds: $(src)/vdso.lds.S FORCE
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$(call if_changed_dep,cpp_lds_S)
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$(obj)/vdso-o32.so.dbg.raw: $(obj)/vdso-o32.lds $(obj-vdso-o32) FORCE
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$(call if_changed,vdsold)
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$(obj)/vdso-o32-image.c: VDSO_NAME := o32
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$(obj)/vdso-o32-image.c: $(obj)/vdso-o32.so.dbg.raw $(obj)/vdso-o32.so.raw \
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$(obj)/genvdso FORCE
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$(call if_changed,genvdso)
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obj-y += vdso-o32-image.o
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endif
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#
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# Build N32 VDSO.
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#
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targets += $(obj-vdso-y:%.o=%-n32.o)
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targets += vdso-n32.lds
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targets += vdso-n32.so.dbg.raw vdso-n32.so.raw
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targets += vdso-n32.so.dbg vdso-n32.so
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targets += vdso-n32-image.c
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ifdef CONFIG_MIPS32_N32
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obj-vdso-n32 := $(obj-vdso-y:%.o=$(obj)/%-n32.o)
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$(obj-vdso-n32): KBUILD_CFLAGS := $(cflags-vdso) -mabi=n32
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$(obj-vdso-n32): KBUILD_AFLAGS := $(aflags-vdso) -mabi=n32
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$(obj)/%-n32.o: $(src)/%.S FORCE
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$(call if_changed_dep,vdsoas_o_S)
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$(obj)/%-n32.o: $(src)/%.c FORCE
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$(call cmd,force_checksrc)
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$(call if_changed_rule,cc_o_c)
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$(obj)/vdso-n32.lds: KBUILD_CPPFLAGS := -mabi=n32
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$(obj)/vdso-n32.lds: $(src)/vdso.lds.S FORCE
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$(call if_changed_dep,cpp_lds_S)
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$(obj)/vdso-n32.so.dbg.raw: $(obj)/vdso-n32.lds $(obj-vdso-n32) FORCE
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$(call if_changed,vdsold)
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$(obj)/vdso-n32-image.c: VDSO_NAME := n32
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$(obj)/vdso-n32-image.c: $(obj)/vdso-n32.so.dbg.raw $(obj)/vdso-n32.so.raw \
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$(obj)/genvdso FORCE
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$(call if_changed,genvdso)
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obj-y += vdso-n32-image.o
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endif
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# FIXME: Need install rule for debug.
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# Needs to deal with dependency for generation of dbg by cmd_genvdso...
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