mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-31 08:28:13 +00:00
0f6372e522
This change removes all instances of DISABLE_LTO from Makefiles, as they are currently unused, and the preferred method of disabling LTO is to filter out the flags instead. Note added by Masahiro Yamada: DISABLE_LTO was added as preparation for GCC LTO, but GCC LTO was not pulled into the mainline. (https://lkml.org/lkml/2014/4/8/272) Suggested-by: Kees Cook <keescook@chromium.org> Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
211 lines
6.6 KiB
Makefile
211 lines
6.6 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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#
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# Building vDSO images for x86.
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#
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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_X86_64_JUMP_SLOT|R_X86_64_GLOB_DAT|R_X86_64_RELATIVE|
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ARCH_REL_TYPE_ABS += R_386_GLOB_DAT|R_386_JMP_SLOT|R_386_RELATIVE
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include $(srctree)/lib/vdso/Makefile
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# Sanitizer runtimes are unavailable and cannot be linked here.
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KASAN_SANITIZE := n
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UBSAN_SANITIZE := n
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KCSAN_SANITIZE := n
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OBJECT_FILES_NON_STANDARD := y
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# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
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KCOV_INSTRUMENT := n
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VDSO64-$(CONFIG_X86_64) := y
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VDSOX32-$(CONFIG_X86_X32_ABI) := y
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VDSO32-$(CONFIG_X86_32) := y
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VDSO32-$(CONFIG_IA32_EMULATION) := y
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# files to link into the vdso
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vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
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vobjs32-y := vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o
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vobjs32-y += vdso32/vclock_gettime.o
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# files to link into kernel
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obj-y += vma.o
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KASAN_SANITIZE_vma.o := y
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UBSAN_SANITIZE_vma.o := y
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KCSAN_SANITIZE_vma.o := y
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OBJECT_FILES_NON_STANDARD_vma.o := n
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# vDSO images to build
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vdso_img-$(VDSO64-y) += 64
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vdso_img-$(VDSOX32-y) += x32
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vdso_img-$(VDSO32-y) += 32
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obj-$(VDSO32-y) += vdso32-setup.o
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vobjs := $(foreach F,$(vobjs-y),$(obj)/$F)
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vobjs32 := $(foreach F,$(vobjs32-y),$(obj)/$F)
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$(obj)/vdso.o: $(obj)/vdso.so
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targets += vdso.lds $(vobjs-y)
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targets += vdso32/vdso32.lds $(vobjs32-y)
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# Build the vDSO image C files and link them in.
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vdso_img_objs := $(vdso_img-y:%=vdso-image-%.o)
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vdso_img_cfiles := $(vdso_img-y:%=vdso-image-%.c)
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vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg)
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obj-y += $(vdso_img_objs)
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targets += $(vdso_img_cfiles)
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targets += $(vdso_img_sodbg) $(vdso_img-y:%=vdso%.so)
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CPPFLAGS_vdso.lds += -P -C
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VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --no-undefined \
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-z max-page-size=4096
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$(obj)/vdso64.so.dbg: $(obj)/vdso.lds $(vobjs) FORCE
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$(call if_changed,vdso_and_check)
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HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/$(SUBARCH)/include/uapi
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hostprogs += vdso2c
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quiet_cmd_vdso2c = VDSO2C $@
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cmd_vdso2c = $(obj)/vdso2c $< $(<:%.dbg=%) $@
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$(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE
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$(call if_changed,vdso2c)
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#
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# Don't omit frame pointers for ease of userspace debugging, but do
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# optimize sibling calls.
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#
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CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \
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$(filter -g%,$(KBUILD_CFLAGS)) -fno-stack-protector \
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-fno-omit-frame-pointer -foptimize-sibling-calls \
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-DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
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ifdef CONFIG_RETPOLINE
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ifneq ($(RETPOLINE_VDSO_CFLAGS),)
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CFL += $(RETPOLINE_VDSO_CFLAGS)
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endif
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endif
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$(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL)
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#
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# vDSO code runs in userspace and -pg doesn't help with profiling anyway.
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#
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CFLAGS_REMOVE_vclock_gettime.o = -pg
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CFLAGS_REMOVE_vdso32/vclock_gettime.o = -pg
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CFLAGS_REMOVE_vgetcpu.o = -pg
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#
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# X32 processes use x32 vDSO to access 64bit kernel data.
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#
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# Build x32 vDSO image:
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# 1. Compile x32 vDSO as 64bit.
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# 2. Convert object files to x32.
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# 3. Build x32 VDSO image with x32 objects, which contains 64bit codes
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# so that it can reach 64bit address space with 64bit pointers.
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#
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CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds)
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VDSO_LDFLAGS_vdsox32.lds = -m elf32_x86_64 -soname linux-vdso.so.1 \
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-z max-page-size=4096
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# x32-rebranded versions
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vobjx32s-y := $(vobjs-y:.o=-x32.o)
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# same thing, but in the output directory
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vobjx32s := $(foreach F,$(vobjx32s-y),$(obj)/$F)
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# Convert 64bit object file to x32 for x32 vDSO.
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quiet_cmd_x32 = X32 $@
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cmd_x32 = $(OBJCOPY) -O elf32-x86-64 $< $@
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$(obj)/%-x32.o: $(obj)/%.o FORCE
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$(call if_changed,x32)
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targets += vdsox32.lds $(vobjx32s-y)
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$(obj)/%.so: OBJCOPYFLAGS := -S
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$(obj)/%.so: $(obj)/%.so.dbg FORCE
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$(call if_changed,objcopy)
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$(obj)/vdsox32.so.dbg: $(obj)/vdsox32.lds $(vobjx32s) FORCE
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$(call if_changed,vdso_and_check)
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CPPFLAGS_vdso32/vdso32.lds = $(CPPFLAGS_vdso.lds)
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VDSO_LDFLAGS_vdso32.lds = -m elf_i386 -soname linux-gate.so.1
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KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS)) -DBUILD_VDSO
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$(obj)/vdso32.so.dbg: KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
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$(obj)/vdso32.so.dbg: asflags-$(CONFIG_X86_64) += -m32
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KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
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KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
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KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
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KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
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KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32))
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KBUILD_CFLAGS_32 := $(filter-out $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS_32))
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KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
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KBUILD_CFLAGS_32 += -fno-stack-protector
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KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)
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KBUILD_CFLAGS_32 += -fno-omit-frame-pointer
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KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING
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ifdef CONFIG_RETPOLINE
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ifneq ($(RETPOLINE_VDSO_CFLAGS),)
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KBUILD_CFLAGS_32 += $(RETPOLINE_VDSO_CFLAGS)
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endif
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endif
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$(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
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$(obj)/vdso32.so.dbg: $(obj)/vdso32/vdso32.lds $(vobjs32) FORCE
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$(call if_changed,vdso_and_check)
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#
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# The DSO images are built using a special linker script.
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#
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quiet_cmd_vdso = VDSO $@
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cmd_vdso = $(LD) -nostdlib -o $@ \
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$(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \
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-T $(filter %.lds,$^) $(filter %.o,$^) && \
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sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@'
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VDSO_LDFLAGS = -shared --hash-style=both --build-id=sha1 \
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$(call ld-option, --eh-frame-hdr) -Bsymbolic
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GCOV_PROFILE := n
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quiet_cmd_vdso_and_check = VDSO $@
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cmd_vdso_and_check = $(cmd_vdso); $(cmd_vdso_check)
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#
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# Install the unstripped copies of vdso*.so. If our toolchain supports
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# build-id, install .build-id links as well.
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#
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quiet_cmd_vdso_install = INSTALL $(@:install_%=%)
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define cmd_vdso_install
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cp $< "$(MODLIB)/vdso/$(@:install_%=%)"; \
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if readelf -n $< |grep -q 'Build ID'; then \
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buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \
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first=`echo $$buildid | cut -b-2`; \
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last=`echo $$buildid | cut -b3-`; \
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mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \
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ln -sf "../../$(@:install_%=%)" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \
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fi
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endef
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vdso_img_insttargets := $(vdso_img_sodbg:%.dbg=install_%)
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$(MODLIB)/vdso: FORCE
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@mkdir -p $(MODLIB)/vdso
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$(vdso_img_insttargets): install_%: $(obj)/%.dbg $(MODLIB)/vdso
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$(call cmd,vdso_install)
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PHONY += vdso_install $(vdso_img_insttargets)
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vdso_install: $(vdso_img_insttargets)
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clean-files := vdso32.so vdso32.so.dbg vdso64* vdso-image-*.c vdsox32.so*
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