c6f21243ce
Pull x86 vdso changes from Peter Anvin: "This is the revamp of the 32-bit vdso and the associated cleanups. This adds timekeeping support to the 32-bit vdso that we already have in the 64-bit vdso. Although 32-bit x86 is legacy, it is likely to remain in the embedded space for a very long time to come. This removes the traditional COMPAT_VDSO support; the configuration variable is reused for simply removing the 32-bit vdso, which will produce correct results but obviously suffer a performance penalty. Only one beta version of glibc was affected, but that version was unfortunately included in one OpenSUSE release. This is not the end of the vdso cleanups. Stefani and Andy have agreed to continue work for the next kernel cycle; in fact Andy has already produced another set of cleanups that came too late for this cycle. An incidental, but arguably important, change is that this ensures that unused space in the VVAR page is properly zeroed. It wasn't before, and would contain whatever garbage was left in memory by BIOS or the bootloader. Since the VVAR page is accessible to user space this had the potential of information leaks" * 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits) x86, vdso: Fix the symbol versions on the 32-bit vDSO x86, vdso, build: Don't rebuild 32-bit vdsos on every make x86, vdso: Actually discard the .discard sections x86, vdso: Fix size of get_unmapped_area() x86, vdso: Finish removing VDSO32_PRELINK x86, vdso: Move more vdso definitions into vdso.h x86: Load the 32-bit vdso in place, just like the 64-bit vdsos x86, vdso32: handle 32 bit vDSO larger one page x86, vdso32: Disable stack protector, adjust optimizations x86, vdso: Zero-pad the VVAR page x86, vdso: Add 32 bit VDSO time support for 64 bit kernel x86, vdso: Add 32 bit VDSO time support for 32 bit kernel x86, vdso: Patch alternatives in the 32-bit VDSO x86, vdso: Introduce VVAR marco for vdso32 x86, vdso: Cleanup __vdso_gettimeofday() x86, vdso: Replace VVAR(vsyscall_gtod_data) by gtod macro x86, vdso: __vdso_clock_gettime() cleanup x86, vdso: Revamp vclock_gettime.c mm: Add new func _install_special_mapping() to mmap.c x86, vdso: Make vsyscall_gtod_data handling x86 generic ...
216 lines
6.4 KiB
Makefile
216 lines
6.4 KiB
Makefile
#
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# Building vDSO images for x86.
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#
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KBUILD_CFLAGS += $(DISABLE_LTO)
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VDSO64-$(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-$(CONFIG_COMPAT) := y
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vdso-install-$(VDSO64-y) += vdso.so
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vdso-install-$(VDSOX32-y) += vdsox32.so
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vdso-install-$(VDSO32-y) += $(vdso32-images)
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# files to link into the vdso
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vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
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vobjs-$(VDSOX32-y) += $(vobjx32s-compat)
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# Filter out x32 objects.
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vobj64s := $(filter-out $(vobjx32s-compat),$(vobjs-y))
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# files to link into kernel
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obj-y += vma.o
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obj-$(VDSO64-y) += vdso.o
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obj-$(VDSOX32-y) += vdsox32.o
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obj-$(VDSO32-y) += vdso32.o vdso32-setup.o
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vobjs := $(foreach F,$(vobj64s),$(obj)/$F)
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$(obj)/vdso.o: $(obj)/vdso.so
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targets += vdso.so vdso.so.dbg vdso.lds $(vobjs-y)
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export CPPFLAGS_vdso.lds += -P -C
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VDSO_LDFLAGS_vdso.lds = -m64 -Wl,-soname=linux-vdso.so.1 \
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-Wl,--no-undefined \
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-Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096 \
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$(DISABLE_LTO)
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$(obj)/vdso.o: $(src)/vdso.S $(obj)/vdso.so
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$(obj)/vdso.so.dbg: $(src)/vdso.lds $(vobjs) FORCE
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$(call if_changed,vdso)
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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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#
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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)) $(call cc-option, -fno-stack-protector) \
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-fno-omit-frame-pointer -foptimize-sibling-calls
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$(vobjs): KBUILD_CFLAGS += $(CFL)
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#
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# vDSO code runs in userspace and -pg doesn't help with profiling anyway.
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#
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CFLAGS_REMOVE_vdso-note.o = -pg
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CFLAGS_REMOVE_vclock_gettime.o = -pg
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CFLAGS_REMOVE_vgetcpu.o = -pg
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CFLAGS_REMOVE_vvar.o = -pg
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targets += vdso-syms.lds
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obj-$(VDSO64-y) += vdso-syms.lds
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#
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# Match symbols in the DSO that look like VDSO*; produce a file of constants.
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#
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sed-vdsosym := -e 's/^00*/0/' \
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-e 's/^\([0-9a-fA-F]*\) . \(VDSO[a-zA-Z0-9_]*\)$$/\2 = 0x\1;/p'
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quiet_cmd_vdsosym = VDSOSYM $@
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define cmd_vdsosym
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$(NM) $< | LC_ALL=C sed -n $(sed-vdsosym) | LC_ALL=C sort > $@
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endef
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$(obj)/%-syms.lds: $(obj)/%.so.dbg FORCE
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$(call if_changed,vdsosym)
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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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targets += vdsox32-syms.lds
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obj-$(VDSOX32-y) += vdsox32-syms.lds
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CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds)
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VDSO_LDFLAGS_vdsox32.lds = -Wl,-m,elf32_x86_64 \
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-Wl,-soname=linux-vdso.so.1 \
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-Wl,-z,max-page-size=4096 \
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-Wl,-z,common-page-size=4096
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vobjx32s-y := $(vobj64s:.o=-x32.o)
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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.so vdsox32.so.dbg vdsox32.lds $(vobjx32s-y)
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$(obj)/vdsox32.o: $(src)/vdsox32.S $(obj)/vdsox32.so
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$(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds $(vobjx32s) FORCE
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$(call if_changed,vdso)
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#
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# Build multiple 32-bit vDSO images to choose from at boot time.
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#
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obj-$(VDSO32-y) += vdso32-syms.lds
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vdso32.so-$(VDSO32-y) += int80
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vdso32.so-$(CONFIG_COMPAT) += syscall
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vdso32.so-$(VDSO32-y) += sysenter
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vdso32-images = $(vdso32.so-y:%=vdso32-%.so)
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CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds)
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VDSO_LDFLAGS_vdso32.lds = -m32 -Wl,-m,elf_i386 -Wl,-soname=linux-gate.so.1
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# This makes sure the $(obj) subdirectory exists even though vdso32/
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# is not a kbuild sub-make subdirectory.
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override obj-dirs = $(dir $(obj)) $(obj)/vdso32/
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targets += vdso32/vdso32.lds
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targets += $(vdso32-images) $(vdso32-images:=.dbg)
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targets += vdso32/note.o vdso32/vclock_gettime.o $(vdso32.so-y:%=vdso32/%.o)
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extra-y += $(vdso32-images)
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$(obj)/vdso32.o: $(vdso32-images:%=$(obj)/%)
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KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS))
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$(vdso32-images:%=$(obj)/%.dbg): KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
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$(vdso32-images:%=$(obj)/%.dbg): asflags-$(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 += -m32 -msoft-float -mregparm=0 -fpic
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KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector)
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KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)
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KBUILD_CFLAGS_32 += -fno-omit-frame-pointer
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$(vdso32-images:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
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$(vdso32-images:%=$(obj)/%.dbg): $(obj)/vdso32-%.so.dbg: FORCE \
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$(obj)/vdso32/vdso32.lds \
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$(obj)/vdso32/vclock_gettime.o \
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$(obj)/vdso32/note.o \
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$(obj)/vdso32/%.o
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$(call if_changed,vdso)
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# Make vdso32-*-syms.lds from each image, and then make sure they match.
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# The only difference should be that some do not define VDSO32_SYSENTER_RETURN.
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targets += vdso32-syms.lds $(vdso32.so-y:%=vdso32-%-syms.lds)
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quiet_cmd_vdso32sym = VDSOSYM $@
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define cmd_vdso32sym
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if LC_ALL=C sort -u $(filter-out FORCE,$^) > $(@D)/.tmp_$(@F) && \
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$(foreach H,$(filter-out FORCE,$^),\
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if grep -q VDSO32_SYSENTER_RETURN $H; \
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then diff -u $(@D)/.tmp_$(@F) $H; \
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else sed /VDSO32_SYSENTER_RETURN/d $(@D)/.tmp_$(@F) | \
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diff -u - $H; fi &&) : ;\
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then mv -f $(@D)/.tmp_$(@F) $@; \
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else rm -f $(@D)/.tmp_$(@F); exit 1; \
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fi
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endef
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$(obj)/vdso32-syms.lds: $(vdso32.so-y:%=$(obj)/vdso32-%-syms.lds) FORCE
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$(call if_changed,vdso32sym)
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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 = $(CC) -nostdlib -o $@ \
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$(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \
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-Wl,-T,$(filter %.lds,$^) $(filter %.o,$^) && \
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sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@'
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VDSO_LDFLAGS = -fPIC -shared $(call cc-ldoption, -Wl$(comma)--hash-style=sysv) \
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$(LTO_CFLAGS)
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GCOV_PROFILE := n
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#
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# Install the unstripped copy of vdso*.so listed in $(vdso-install-y).
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#
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quiet_cmd_vdso_install = INSTALL $@
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cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@
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$(vdso-install-y): %.so: $(obj)/%.so.dbg FORCE
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@mkdir -p $(MODLIB)/vdso
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$(call cmd,vdso_install)
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PHONY += vdso_install $(vdso-install-y)
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vdso_install: $(vdso-install-y)
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clean-files := vdso32-syscall* vdso32-sysenter* vdso32-int80*
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