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# 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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KBUILD_CFLAGS += $(DISABLE_LTO)
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KASAN_SANITIZE			:= n
UBSAN_SANITIZE			:= n
OBJECT_FILES_NON_STANDARD	:= y
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# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
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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# files to link into kernel
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obj-y				+= vma.o
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OBJECT_FILES_NON_STANDARD_vma.o	:= n
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# vDSO images to build
vdso_img-$(VDSO64-y)		+= 64
vdso_img-$(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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$(obj)/vdso.o: $(obj)/vdso.so

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targets += vdso.lds $(vobjs-y)

# Build the vDSO image C files and link them in.
vdso_img_objs := $(vdso_img-y:%=vdso-image-%.o)
vdso_img_cfiles := $(vdso_img-y:%=vdso-image-%.c)
vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg)
obj-y += $(vdso_img_objs)
targets += $(vdso_img_cfiles)
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targets += $(vdso_img_sodbg) $(vdso_img-y:%=vdso%.so)
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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 \
			$(DISABLE_LTO)
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$(obj)/vdso64.so.dbg: $(src)/vdso.lds $(vobjs) FORCE
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	$(call if_changed,vdso)
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HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/$(SUBARCH)/include/uapi
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hostprogs-y			+= vdso2c

quiet_cmd_vdso2c = VDSO2C  $@
define cmd_vdso2c
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	$(obj)/vdso2c $< $(<:%.dbg=%) $@
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endef

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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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#
# Don't omit frame pointers for ease of userspace debugging, but do
# optimize sibling calls.
#
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CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \
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       $(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \
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       -fno-omit-frame-pointer -foptimize-sibling-calls \
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       -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
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$(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS)) $(CFL)
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#
# vDSO code runs in userspace and -pg doesn't help with profiling anyway.
#
CFLAGS_REMOVE_vdso-note.o = -pg
CFLAGS_REMOVE_vclock_gettime.o = -pg
CFLAGS_REMOVE_vgetcpu.o = -pg
CFLAGS_REMOVE_vvar.o = -pg

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#
# X32 processes use x32 vDSO to access 64bit kernel data.
#
# Build x32 vDSO image:
# 1. Compile x32 vDSO as 64bit.
# 2. Convert object files to x32.
# 3. Build x32 VDSO image with x32 objects, which contains 64bit codes
# so that it can reach 64bit address space with 64bit pointers.
#

CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds)
VDSO_LDFLAGS_vdsox32.lds = -Wl,-m,elf32_x86_64 \
			   -Wl,-soname=linux-vdso.so.1 \
			   -Wl,-z,max-page-size=4096 \
			   -Wl,-z,common-page-size=4096

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# 64-bit objects to re-brand as x32
vobjs64-for-x32 := $(filter-out $(vobjs-nox32),$(vobjs-y))

# x32-rebranded versions
vobjx32s-y := $(vobjs64-for-x32:.o=-x32.o)

# same thing, but in the output directory
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vobjx32s := $(foreach F,$(vobjx32s-y),$(obj)/$F)

# Convert 64bit object file to x32 for x32 vDSO.
quiet_cmd_x32 = X32     $@
      cmd_x32 = $(OBJCOPY) -O elf32-x86-64 $< $@

$(obj)/%-x32.o: $(obj)/%.o FORCE
	$(call if_changed,x32)

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targets += vdsox32.lds $(vobjx32s-y)
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$(obj)/%.so: OBJCOPYFLAGS := -S
$(obj)/%.so: $(obj)/%.so.dbg
	$(call if_changed,objcopy)

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$(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds $(vobjx32s) FORCE
	$(call if_changed,vdso)

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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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targets += vdso32/vdso32.lds
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targets += vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o
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targets += vdso32/vclock_gettime.o
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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)
$(obj)/vdso32.so.dbg: asflags-$(CONFIG_X86_64) += -m32
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KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
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 += -m32 -msoft-float -mregparm=0 -fpic
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KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector)
KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)
KBUILD_CFLAGS_32 += -fno-omit-frame-pointer
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KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING
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$(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
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$(obj)/vdso32.so.dbg: FORCE \
		      $(obj)/vdso32/vdso32.lds \
		      $(obj)/vdso32/vclock_gettime.o \
		      $(obj)/vdso32/note.o \
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		      $(obj)/vdso32/system_call.o \
		      $(obj)/vdso32/sigreturn.o
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	$(call if_changed,vdso)

#
# The DSO images are built using a special linker script.
#
quiet_cmd_vdso = VDSO    $@
      cmd_vdso = $(CC) -nostdlib -o $@ \
		       $(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \
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		       -Wl,-T,$(filter %.lds,$^) $(filter %.o,$^) && \
		 sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@'
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VDSO_LDFLAGS = -fPIC -shared $(call cc-ldoption, -Wl$(comma)--hash-style=both) \
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	$(call cc-ldoption, -Wl$(comma)--build-id) -Wl,-Bsymbolic $(LTO_CFLAGS)
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GCOV_PROFILE := n
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#
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# Install the unstripped copies of vdso*.so.  If our toolchain supports
# 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
	cp $< "$(MODLIB)/vdso/$(@:install_%=%)"; \
	if readelf -n $< |grep -q 'Build ID'; then \
	  buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \
	  first=`echo $$buildid | cut -b-2`; \
	  last=`echo $$buildid | cut -b3-`; \
	  mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \
	  ln -sf "../../$(@:install_%=%)" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \
	fi
endef
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vdso_img_insttargets := $(vdso_img_sodbg:%.dbg=install_%)

$(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*