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# SPDX-License-Identifier: GPL-2.0
#
# Building vDSO images for x86.
#
# Include the generic Makefile to check the built vDSO:
include $(srctree)/lib/vdso/Makefile.include
obj-y += $(foreach x,$(vdsos-y),vdso$(x)-image.o)
targets += $(foreach x,$(vdsos-y),vdso$(x)-image.c vdso$(x).so vdso$(x).so.dbg vdso$(x).lds)
targets += $(vobjs-y)
# vobjs-y with $(obj)/ prepended
vobjs := $(addprefix $(obj)/,$(vobjs-y))
# Options for vdso*.lds
CPPFLAGS_VDSO_LDS := -P -C -I$(src)/..
$(obj)/%.lds : KBUILD_CPPFLAGS += $(CPPFLAGS_VDSO_LDS)
#
# Options from KBUILD_[AC]FLAGS that should *NOT* be kept
#
flags-remove-y += \
-D__KERNEL__ -mcmodel=kernel -mregparm=3 \
-fno-pic -fno-PIC -fno-pie -fno-PIE \
-mfentry -pg \
$(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) $(KSTACK_ERASE_CFLAGS) \
$(RETPOLINE_CFLAGS) $(CC_FLAGS_LTO) $(CC_FLAGS_CFI) \
$(PADDING_CFLAGS)
#
# Don't omit frame pointers for ease of userspace debugging, but do
# optimize sibling calls.
#
flags-y += -D__DISABLE_EXPORTS
flags-y += -DDISABLE_BRANCH_PROFILING
flags-y += -DBUILD_VDSO
flags-y += -I$(src)/.. -I$(srctree)
flags-y += -O2 -fpic
flags-y += -fno-stack-protector
flags-y += -fno-omit-frame-pointer
flags-y += -foptimize-sibling-calls
flags-y += -fasynchronous-unwind-tables
# Reset cf protections enabled by compiler default
flags-y += $(call cc-option, -fcf-protection=none)
flags-$(X86_USER_SHADOW_STACK) += $(call cc-option, -fcf-protection=return)
# When user space IBT is supported, enable this.
# flags-$(CONFIG_USER_IBT) += $(call cc-option, -fcf-protection=branch)
flags-$(CONFIG_MITIGATION_RETPOLINE) += $(RETPOLINE_VDSO_CFLAGS)
# These need to be conditional on $(vobjs) as they do not apply to
# the output vdso*-image.o files which are standard kernel objects.
$(vobjs) : KBUILD_AFLAGS := \
$(filter-out $(flags-remove-y),$(KBUILD_AFLAGS)) $(flags-y)
$(vobjs) : KBUILD_CFLAGS := \
$(filter-out $(flags-remove-y),$(KBUILD_CFLAGS)) $(flags-y)
#
# The VDSO images are built using a special linker script.
#
VDSO_LDFLAGS := -shared --hash-style=both --build-id=sha1 --no-undefined \
$(call ld-option, --eh-frame-hdr) -Bsymbolic -z noexecstack
quiet_cmd_vdso = VDSO $@
cmd_vdso = $(LD) -o $@ \
$(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$*) \
-T $(filter %.lds,$^) $(filter %.o,$^)
quiet_cmd_vdso_and_check = VDSO $@
cmd_vdso_and_check = $(cmd_vdso); $(cmd_vdso_check)
$(obj)/vdso%.so.dbg: $(obj)/vdso%.lds FORCE
$(call if_changed,vdso_and_check)
$(obj)/%.so: OBJCOPYFLAGS := -S --remove-section __ex_table
$(obj)/%.so: $(obj)/%.so.dbg FORCE
$(call if_changed,objcopy)
VDSO2C = $(objtree)/arch/x86/tools/vdso2c
quiet_cmd_vdso2c = VDSO2C $@
cmd_vdso2c = $(VDSO2C) $< $(<:%.dbg=%) $@
$(obj)/%-image.c: $(obj)/%.so.dbg $(obj)/%.so $(VDSO2C) FORCE
$(call if_changed,vdso2c)
$(obj)/%-image.o: $(obj)/%-image.c
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