#
  # arch/arm64/Makefile
  #
  # This file is included by the global makefile so that you can add your own
  # architecture-specific flags and dependencies.
  #
  # This file is subject to the terms and conditions of the GNU General Public
  # License.  See the file "COPYING" in the main directory of this archive
  # for more details.
  #
  # Copyright (C) 1995-2001 by Russell King

  LDFLAGS_vmlinux	:=--no-undefined -X

  ifeq ($(CONFIG_RELOCATABLE), y)
  # Pass --no-apply-dynamic-relocs to restore pre-binutils-2.27 behaviour
  # for relative relocs, since this leads to better Image compression
  # with the relocation offsets always being zero.

  LDFLAGS_vmlinux		+= -shared -Bsymbolic -z notext \

  			$(call ld-option, --no-apply-dynamic-relocs)

  endif

  ifeq ($(CONFIG_ARM64_ERRATUM_843419),y)
    ifeq ($(call ld-option, --fix-cortex-a53-843419),)
  $(warning ld does not support --fix-cortex-a53-843419; kernel may be susceptible to erratum)
    else
  LDFLAGS_vmlinux	+= --fix-cortex-a53-843419
    endif
  endif

  ifeq ($(CONFIG_ARM64_USE_LSE_ATOMICS), y)
    ifneq ($(CONFIG_ARM64_LSE_ATOMICS), y)

  $(warning LSE atomics not supported by binutils)
    endif
  endif

  cc_has_k_constraint := $(call try-run,echo				\
  	'int main(void) {						\
  		asm volatile("and w0, w0, %w0" :: "K" (4294967295));	\
  		return 0;						\
  	}' | $(CC) -S -x c -o "$$TMP" -,,-DCONFIG_CC_HAS_K_CONSTRAINT=1)

  ifeq ($(CONFIG_BROKEN_GAS_INST),y)

  $(warning Detected assembler with broken .inst; disassembly will be unreliable)
  endif

  KBUILD_CFLAGS	+= -mgeneral-regs-only	\

  		   $(compat_vdso) $(cc_has_k_constraint)

  KBUILD_CFLAGS	+= $(call cc-disable-warning, psabi)

  KBUILD_AFLAGS	+= $(compat_vdso)

  KBUILD_CFLAGS	+= $(call cc-option,-mabi=lp64)
  KBUILD_AFLAGS	+= $(call cc-option,-mabi=lp64)

  # Avoid generating .eh_frame* sections.
  KBUILD_CFLAGS	+= -fno-asynchronous-unwind-tables -fno-unwind-tables
  KBUILD_AFLAGS	+= -fno-asynchronous-unwind-tables -fno-unwind-tables

  ifeq ($(CONFIG_STACKPROTECTOR_PER_TASK),y)
  prepare: stack_protector_prepare
  stack_protector_prepare: prepare0
  	$(eval KBUILD_CFLAGS += -mstack-protector-guard=sysreg		  \
  				-mstack-protector-guard-reg=sp_el0	  \
  				-mstack-protector-guard-offset=$(shell	  \
  			awk '{if ($$2 == "TSK_STACK_CANARY") print $$3;}' \
  					include/generated/asm-offsets.h))
  endif

  # Ensure that if the compiler supports branch protection we default it
  # off, this will be overridden if we are using branch protection.
  branch-prot-flags-y += $(call cc-option,-mbranch-protection=none)

  ifeq ($(CONFIG_ARM64_PTR_AUTH),y)
  branch-prot-flags-$(CONFIG_CC_HAS_SIGN_RETURN_ADDRESS) := -msign-return-address=all

  # We enable additional protection for leaf functions as there is some
  # narrow potential for ROP protection benefits and no substantial
  # performance impact has been observed.

  ifeq ($(CONFIG_ARM64_BTI_KERNEL),y)
  branch-prot-flags-$(CONFIG_CC_HAS_BRANCH_PROT_PAC_RET_BTI) := -mbranch-protection=pac-ret+leaf+bti
  else

  branch-prot-flags-$(CONFIG_CC_HAS_BRANCH_PROT_PAC_RET) := -mbranch-protection=pac-ret+leaf

  endif

  # -march=armv8.3-a enables the non-nops instructions for PAC, to avoid the
  # compiler to generate them and consequently to break the single image contract
  # we pass it only to the assembler. This option is utilized only in case of non
  # integrated assemblers.

  ifeq ($(CONFIG_AS_HAS_PAC), y)
  asm-arch := armv8.3-a

  endif

  endif

  KBUILD_CFLAGS += $(branch-prot-flags-y)

  ifeq ($(CONFIG_AS_HAS_ARMV8_4), y)
  # make sure to pass the newest target architecture to -march.

  asm-arch := armv8.4-a
  endif
  
  ifdef asm-arch
  KBUILD_CFLAGS	+= -Wa,-march=$(asm-arch) \
  		   -DARM64_ASM_ARCH='"$(asm-arch)"'

  endif

  ifeq ($(CONFIG_SHADOW_CALL_STACK), y)
  KBUILD_CFLAGS	+= -ffixed-x18
  endif

  ifeq ($(CONFIG_CPU_BIG_ENDIAN), y)
  KBUILD_CPPFLAGS	+= -mbig-endian

  CHECKFLAGS	+= -D__AARCH64EB__

  # Prefer the baremetal ELF build target, but not all toolchains include
  # it so fall back to the standard linux version if needed.

  KBUILD_LDFLAGS	+= -EB $(call ld-option, -maarch64elfb, -maarch64linuxb -z norelro)

  UTS_MACHINE	:= aarch64_be

  else

  KBUILD_CPPFLAGS	+= -mlittle-endian

  CHECKFLAGS	+= -D__AARCH64EL__

  # Same as above, prefer ELF but fall back to linux target if needed.

  KBUILD_LDFLAGS	+= -EL $(call ld-option, -maarch64elf, -maarch64linux -z norelro)

  UTS_MACHINE	:= aarch64

  endif

  ifeq ($(CONFIG_LD_IS_LLD), y)
  KBUILD_LDFLAGS	+= -z norelro
  endif

  CHECKFLAGS	+= -D__aarch64__

  ifeq ($(CONFIG_DYNAMIC_FTRACE_WITH_REGS),y)
    KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY
    CC_FLAGS_FTRACE := -fpatchable-function-entry=2
  endif

  # Default value
  head-y		:= arch/arm64/kernel/head.o

  ifeq ($(CONFIG_KASAN_SW_TAGS), y)
  KASAN_SHADOW_SCALE_SHIFT := 4
  else
  KASAN_SHADOW_SCALE_SHIFT := 3
  endif
  
  KBUILD_CFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
  KBUILD_CPPFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
  KBUILD_AFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)

  core-y		+= arch/arm64/

  libs-y		:= arch/arm64/lib/ $(libs-y)

  libs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a

  
  # Default target when executing plain make

  boot		:= arch/arm64/boot
  KBUILD_IMAGE	:= $(boot)/Image.gz

  all:	Image.gz

  Image: vmlinux
  	$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@

  Image.%: Image

  	$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@

  zinstall install:

  	$(Q)$(MAKE) $(build)=$(boot) $@

  PHONY += vdso_install
  vdso_install:
  	$(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso $@

  	$(if $(CONFIG_COMPAT_VDSO), \
  		$(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso32 $@)

  # We use MRPROPER_FILES and CLEAN_FILES now
  archclean:
  	$(Q)$(MAKE) $(clean)=$(boot)

  ifeq ($(KBUILD_EXTMOD),)

  # We need to generate vdso-offsets.h before compiling certain files in kernel/.
  # In order to do that, we should use the archprepare target, but we can't since
  # asm-offsets.h is included in some files used to generate vdso-offsets.h, and
  # asm-offsets.h is built in prepare0, for which archprepare is a dependency.
  # Therefore we need to generate the header after prepare0 has been made, hence
  # this hack.
  prepare: vdso_prepare
  vdso_prepare: prepare0
  	$(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso include/generated/vdso-offsets.h

  	$(if $(CONFIG_COMPAT_VDSO),$(Q)$(MAKE) \
  		$(build)=arch/arm64/kernel/vdso32  \
  		include/generated/vdso32-offsets.h)

  endif

  define archhelp
    echo  '* Image.gz      - Compressed kernel image (arch/$(ARCH)/boot/Image.gz)'
    echo  '  Image         - Uncompressed kernel image (arch/$(ARCH)/boot/Image)'
    echo  '  install       - Install uncompressed kernel'
    echo  '  zinstall      - Install compressed kernel'
    echo  '                  Install using (your) ~/bin/installkernel or'
    echo  '                  (distribution) /sbin/installkernel or'
    echo  '                  install to $$(INSTALL_PATH) and run lilo'
  endef