forked from luck/tmp_suning_uos_patched
2ff906994b
Currently, the VDSO is being linked through $(CC). This does not match how the rest of the kernel links objects, which is through the $(LD) variable. When clang is built in a default configuration, it first attempts to use the target triple's default linker then the system's default linker, unless told otherwise through -fuse-ld=... We do not use -fuse-ld= because it can be brittle and we have support for invoking $(LD) directly. See commitfe00e50b2d("ARM: 8858/1: vdso: use $(LD) instead of $(CC) to link VDSO") and commit691efbedc6("arm64: vdso: use $(LD) instead of $(CC) to link VDSO") for examples of doing this in the VDSO. Do the same thing here. Replace the custom linking logic with $(cmd_ld) and ldflags-y so that $(LD) is respected. We need to explicitly add two flags to the linker that were implicitly passed by the compiler: -G 0 (which comes from ccflags-vdso) and --eh-frame-hdr. Before this patch (generated by adding '-v' to VDSO_LDFLAGS): <gcc_prefix>/libexec/gcc/mips64-linux/9.3.0/collect2 \ -plugin <gcc_prefix>/libexec/gcc/mips64-linux/9.3.0/liblto_plugin.so \ -plugin-opt=<gcc_prefix>/libexec/gcc/mips64-linux/9.3.0/lto-wrapper \ -plugin-opt=-fresolution=/tmp/ccGEi5Ka.res \ --eh-frame-hdr \ -G 0 \ -EB \ -mips64r2 \ -shared \ -melf64btsmip \ -o arch/mips/vdso/vdso.so.dbg.raw \ -L<gcc_prefix>/lib/gcc/mips64-linux/9.3.0/64 \ -L<gcc_prefix>/lib/gcc/mips64-linux/9.3.0 \ -L<gcc_prefix>/lib/gcc/mips64-linux/9.3.0/../../../../mips64-linux/lib \ -Bsymbolic \ --no-undefined \ -soname=linux-vdso.so.1 \ -EB \ --hash-style=sysv \ --build-id \ -T arch/mips/vdso/vdso.lds \ arch/mips/vdso/elf.o \ arch/mips/vdso/vgettimeofday.o \ arch/mips/vdso/sigreturn.o After this patch: <gcc_prefix>/bin/mips64-linux-ld \ -m elf64btsmip \ -Bsymbolic \ --no-undefined \ -soname=linux-vdso.so.1 \ -EB \ -nostdlib \ -shared \ -G 0 \ --eh-frame-hdr \ --hash-style=sysv \ --build-id \ -T arch/mips/vdso/vdso.lds \ arch/mips/vdso/elf.o \ arch/mips/vdso/vgettimeofday.o arch/mips/vdso/sigreturn.o \ -o arch/mips/vdso/vdso.so.dbg.raw Note that we leave behind -mips64r2. Turns out that ld ignores it (see get_emulation in ld/ldmain.c). This is true of current trunk and 2.23, which is the minimum supported version for the kernel: https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=ld/ldmain.c;hb=aa4209e7b679afd74a3860ce25659e71cc4847d5#l593 https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=ld/ldmain.c;hb=a55e30b51bc6227d8d41f707654d0a5620978dcf#l641 Before this patch, LD=ld.lld did nothing: $ llvm-readelf -p.comment arch/mips/vdso/vdso.so.dbg | sed 's/(.*//' String dump of section '.comment': [ 0] ClangBuiltLinux clang version 11.0.0 After this patch, it does: $ llvm-readelf -p.comment arch/mips/vdso/vdso.so.dbg | sed 's/(.*//' String dump of section '.comment': [ 0] Linker: LLD 11.0.0 [ 62] ClangBuiltLinux clang version 11.0.0 Link: https://github.com/ClangBuiltLinux/linux/issues/785 Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
213 lines
6.1 KiB
Makefile
213 lines
6.1 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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# Objects to go into the VDSO.
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# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before
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# the inclusion of generic Makefile.
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ARCH_REL_TYPE_ABS := R_MIPS_JUMP_SLOT|R_MIPS_GLOB_DAT
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include $(srctree)/lib/vdso/Makefile
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obj-vdso-y := elf.o vgettimeofday.o sigreturn.o
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# Common compiler flags between ABIs.
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ccflags-vdso := \
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$(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,$(KBUILD_CFLAGS)) \
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$(filter -mno-loongson-%,$(KBUILD_CFLAGS)) \
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-D__VDSO__
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ifndef CONFIG_64BIT
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ccflags-vdso += -DBUILD_VDSO32
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endif
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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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#
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# The -fno-jump-tables flag only prevents the compiler from generating
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# jump tables but does not prevent the compiler from emitting absolute
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# offsets.
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cflags-vdso := $(ccflags-vdso) \
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$(filter -W%,$(filter-out -Wa$(comma)%,$(KBUILD_CFLAGS))) \
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-O3 -g -fPIC -fno-strict-aliasing -fno-common -fno-builtin -G 0 \
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-mrelax-pic-calls $(call cc-option, -mexplicit-relocs) \
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-fno-stack-protector -fno-jump-tables -DDISABLE_BRANCH_PROFILING \
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$(call cc-option, -fno-asynchronous-unwind-tables) \
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$(call cc-option, -fno-stack-protector)
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aflags-vdso := $(ccflags-vdso) \
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-D__ASSEMBLY__ -Wa,-gdwarf-2
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ifneq ($(c-gettimeofday-y),)
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CFLAGS_vgettimeofday.o = -include $(c-gettimeofday-y)
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# config-n32-o32-env.c prepares the environment to build a 32bit vDSO
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# library on a 64bit kernel.
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# Note: Needs to be included before than the generic library.
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CFLAGS_vgettimeofday-o32.o = -include $(srctree)/$(src)/config-n32-o32-env.c -include $(c-gettimeofday-y)
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CFLAGS_vgettimeofday-n32.o = -include $(srctree)/$(src)/config-n32-o32-env.c -include $(c-gettimeofday-y)
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endif
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CFLAGS_REMOVE_vgettimeofday.o = -pg
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ifdef CONFIG_MIPS_DISABLE_VDSO
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ifndef CONFIG_MIPS_LD_CAN_LINK_VDSO
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$(warning MIPS VDSO requires binutils >= 2.25)
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endif
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obj-vdso-y := $(filter-out vgettimeofday.o, $(obj-vdso-y))
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endif
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# VDSO linker flags.
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ldflags-y := -Bsymbolic --no-undefined -soname=linux-vdso.so.1 \
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$(filter -E%,$(KBUILD_CFLAGS)) -nostdlib -shared \
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-G 0 --eh-frame-hdr --hash-style=sysv --build-id -T
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CFLAGS_REMOVE_vdso.o = -pg
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GCOV_PROFILE := n
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UBSAN_SANITIZE := n
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KCOV_INSTRUMENT := n
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# Check that we don't have PIC 'jalr t9' calls left
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quiet_cmd_vdso_mips_check = VDSOCHK $@
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cmd_vdso_mips_check = if $(OBJDUMP) --disassemble $@ | egrep -h "jalr.*t9" > /dev/null; \
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then (echo >&2 "$@: PIC 'jalr t9' calls are not supported"; \
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rm -f $@; /bin/false); fi
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#
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# Shared build commands.
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#
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quiet_cmd_vdsold_and_vdso_check = LD $@
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cmd_vdsold_and_vdso_check = $(cmd_ld); $(cmd_vdso_check); $(cmd_vdso_mips_check)
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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 := 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_and_vdso_check)
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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 := $(ccflags-vdso) -mabi=32
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$(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_and_vdso_check)
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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 := $(ccflags-vdso) -mabi=n32
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$(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_and_vdso_check)
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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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