Kconfig

	depends on XEN

config XEN
	bool "Xen guest support on ARM64"
	depends on ARM64 && OF
	select SWIOTLB_XEN
	select PARAVIRT
	help
	  Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.

config FORCE_MAX_ZONEORDER
	int
	default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE)
	default "12" if (ARM64_16K_PAGES && TRANSPARENT_HUGEPAGE)
	default "11"
	help
	  The kernel memory allocator divides physically contiguous memory
	  blocks into "zones", where each zone is a power of two number of
	  pages.  This option selects the largest power of two that the kernel
	  keeps in the memory allocator.  If you need to allocate very large
	  blocks of physically contiguous memory, then you may need to
	  increase this value.

	  This config option is actually maximum order plus one. For example,
	  a value of 11 means that the largest free memory block is 2^10 pages.

	  We make sure that we can allocate upto a HugePage size for each configuration.
	  Hence we have :
		MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2

	  However for 4K, we choose a higher default value, 11 as opposed to 10, giving us
	  4M allocations matching the default size used by generic code.

config UNMAP_KERNEL_AT_EL0
	bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT
	default y
	help
	  Speculation attacks against some high-performance processors can
	  be used to bypass MMU permission checks and leak kernel data to
	  userspace. This can be defended against by unmapping the kernel
	  when running in userspace, mapping it back in on exception entry
	  via a trampoline page in the vector table.

	  If unsure, say Y.

config HARDEN_BRANCH_PREDICTOR
	bool "Harden the branch predictor against aliasing attacks" if EXPERT
	default y
	help
	  Speculation attacks against some high-performance processors rely on
	  being able to manipulate the branch predictor for a victim context by
	  executing aliasing branches in the attacker context.  Such attacks
	  can be partially mitigated against by clearing internal branch
	  predictor state and limiting the prediction logic in some situations.

	  This config option will take CPU-specific actions to harden the
	  branch predictor against aliasing attacks and may rely on specific
	  instruction sequences or control bits being set by the system
	  firmware.

	  If unsure, say Y.

config HARDEN_EL2_VECTORS
	bool "Harden EL2 vector mapping against system register leak" if EXPERT
	default y
	help
	  Speculation attacks against some high-performance processors can
	  be used to leak privileged information such as the vector base
	  register, resulting in a potential defeat of the EL2 layout
	  randomization.

	  This config option will map the vectors to a fixed location,
	  independent of the EL2 code mapping, so that revealing VBAR_EL2
	  to an attacker does not give away any extra information. This
	  only gets enabled on affected CPUs.

	  If unsure, say Y.

config ARM64_SSBD
	bool "Speculative Store Bypass Disable" if EXPERT
	default y
	help
	  This enables mitigation of the bypassing of previous stores
	  by speculative loads.

	  If unsure, say Y.

config RODATA_FULL_DEFAULT_ENABLED
	bool "Apply r/o permissions of VM areas also to their linear aliases"
	default y
	help
	  Apply read-only attributes of VM areas to the linear alias of
	  the backing pages as well. This prevents code or read-only data
	  from being modified (inadvertently or intentionally) via another
	  mapping of the same memory page. This additional enhancement can
	  be turned off at runtime by passing rodata=[off|on] (and turned on
	  with rodata=full if this option is set to 'n')

	  This requires the linear region to be mapped down to pages,
	  which may adversely affect performance in some cases.

config ARM64_SW_TTBR0_PAN
	bool "Emulate Privileged Access Never using TTBR0_EL1 switching"
	help
	  Enabling this option prevents the kernel from accessing
	  user-space memory directly by pointing TTBR0_EL1 to a reserved
	  zeroed area and reserved ASID. The user access routines
	  restore the valid TTBR0_EL1 temporarily.

menuconfig COMPAT
	bool "Kernel support for 32-bit EL0"
	depends on ARM64_4K_PAGES || EXPERT
	select COMPAT_BINFMT_ELF if BINFMT_ELF
	select HAVE_UID16
	select OLD_SIGSUSPEND3
	select COMPAT_OLD_SIGACTION
	help
	  This option enables support for a 32-bit EL0 running under a 64-bit
	  kernel at EL1. AArch32-specific components such as system calls,
	  the user helper functions, VFP support and the ptrace interface are
	  handled appropriately by the kernel.

	  If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware
	  that you will only be able to execute AArch32 binaries that were compiled
	  with page size aligned segments.

	  If you want to execute 32-bit userspace applications, say Y.

if COMPAT

config KUSER_HELPERS
	bool "Enable kuser helpers page for 32 bit applications"
	default y
	help
	  Warning: disabling this option may break 32-bit user programs.

	  Provide kuser helpers to compat tasks. The kernel provides
	  helper code to userspace in read only form at a fixed location
	  to allow userspace to be independent of the CPU type fitted to
	  the system. This permits binaries to be run on ARMv4 through
	  to ARMv8 without modification.

	  See Documentation/arm/kernel_user_helpers.txt for details.

	  However, the fixed address nature of these helpers can be used
	  by ROP (return orientated programming) authors when creating
	  exploits.

	  If all of the binaries and libraries which run on your platform
	  are built specifically for your platform, and make no use of
	  these helpers, then you can turn this option off to hinder
	  such exploits. However, in that case, if a binary or library
	  relying on those helpers is run, it will not function correctly.

	  Say N here only if you are absolutely certain that you do not
	  need these helpers; otherwise, the safe option is to say Y.


menuconfig ARMV8_DEPRECATED
	bool "Emulate deprecated/obsolete ARMv8 instructions"
	depends on SYSCTL
	help
	  Legacy software support may require certain instructions
	  that have been deprecated or obsoleted in the architecture.

	  Enable this config to enable selective emulation of these
	  features.

	  If unsure, say Y

if ARMV8_DEPRECATED

config SWP_EMULATION
	bool "Emulate SWP/SWPB instructions"
	help
	  ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that
	  they are always undefined. Say Y here to enable software
	  emulation of these instructions for userspace using LDXR/STXR.

	  In some older versions of glibc [<=2.8] SWP is used during futex
	  trylock() operations with the assumption that the code will not
	  be preempted. This invalid assumption may be more likely to fail
	  with SWP emulation enabled, leading to deadlock of the user
	  application.

	  NOTE: when accessing uncached shared regions, LDXR/STXR rely
	  on an external transaction monitoring block called a global
	  monitor to maintain update atomicity. If your system does not
	  implement a global monitor, this option can cause programs that
	  perform SWP operations to uncached memory to deadlock.

	  If unsure, say Y

config CP15_BARRIER_EMULATION
	bool "Emulate CP15 Barrier instructions"
	help
	  The CP15 barrier instructions - CP15ISB, CP15DSB, and
	  CP15DMB - are deprecated in ARMv8 (and ARMv7). It is
	  strongly recommended to use the ISB, DSB, and DMB
	  instructions instead.

	  Say Y here to enable software emulation of these
	  instructions for AArch32 userspace code. When this option is
	  enabled, CP15 barrier usage is traced which can help
	  identify software that needs updating.

	  If unsure, say Y

config SETEND_EMULATION
	bool "Emulate SETEND instruction"
	help
	  The SETEND instruction alters the data-endianness of the
	  AArch32 EL0, and is deprecated in ARMv8.

	  Say Y here to enable software emulation of the instruction
	  for AArch32 userspace code.

	  Note: All the cpus on the system must have mixed endian support at EL0
	  for this feature to be enabled. If a new CPU - which doesn't support mixed
	  endian - is hotplugged in after this feature has been enabled, there could
	  be unexpected results in the applications.

	  If unsure, say Y
endif

endif

menu "ARMv8.1 architectural features"

config ARM64_HW_AFDBM
	bool "Support for hardware updates of the Access and Dirty page flags"
	default y
	help
	  The ARMv8.1 architecture extensions introduce support for
	  hardware updates of the access and dirty information in page
	  table entries. When enabled in TCR_EL1 (HA and HD bits) on
	  capable processors, accesses to pages with PTE_AF cleared will
	  set this bit instead of raising an access flag fault.
	  Similarly, writes to read-only pages with the DBM bit set will
	  clear the read-only bit (AP[2]) instead of raising a
	  permission fault.

	  Kernels built with this configuration option enabled continue
	  to work on pre-ARMv8.1 hardware and the performance impact is
	  minimal. If unsure, say Y.

config ARM64_PAN
	bool "Enable support for Privileged Access Never (PAN)"
	default y
	help
	 Privileged Access Never (PAN; part of the ARMv8.1 Extensions)
	 prevents the kernel or hypervisor from accessing user-space (EL0)
	 memory directly.

	 Choosing this option will cause any unprotected (not using
	 copy_to_user et al) memory access to fail with a permission fault.

	 The feature is detected at runtime, and will remain as a 'nop'
	 instruction if the cpu does not implement the feature.

config ARM64_LSE_ATOMICS
	bool "Atomic instructions"
	default y
	help
	  As part of the Large System Extensions, ARMv8.1 introduces new
	  atomic instructions that are designed specifically to scale in
	  very large systems.

	  Say Y here to make use of these instructions for the in-kernel
	  atomic routines. This incurs a small overhead on CPUs that do
	  not support these instructions and requires the kernel to be
	  built with binutils >= 2.25 in order for the new instructions
	  to be used.

config ARM64_VHE
	bool "Enable support for Virtualization Host Extensions (VHE)"
	default y
	help
	  Virtualization Host Extensions (VHE) allow the kernel to run
	  directly at EL2 (instead of EL1) on processors that support
	  it. This leads to better performance for KVM, as they reduce
	  the cost of the world switch.

	  Selecting this option allows the VHE feature to be detected
	  at runtime, and does not affect processors that do not
	  implement this feature.

endmenu

menu "ARMv8.2 architectural features"

config ARM64_UAO
	bool "Enable support for User Access Override (UAO)"
	default y
	help
	  User Access Override (UAO; part of the ARMv8.2 Extensions)
	  causes the 'unprivileged' variant of the load/store instructions to
	  be overridden to be privileged.

	  This option changes get_user() and friends to use the 'unprivileged'
	  variant of the load/store instructions. This ensures that user-space
	  really did have access to the supplied memory. When addr_limit is
	  set to kernel memory the UAO bit will be set, allowing privileged
	  access to kernel memory.

	  Choosing this option will cause copy_to_user() et al to use user-space
	  memory permissions.

	  The feature is detected at runtime, the kernel will use the
	  regular load/store instructions if the cpu does not implement the
	  feature.

config ARM64_PMEM
	bool "Enable support for persistent memory"
	select ARCH_HAS_PMEM_API
	select ARCH_HAS_UACCESS_FLUSHCACHE
	help
	  Say Y to enable support for the persistent memory API based on the
	  ARMv8.2 DCPoP feature.

	  The feature is detected at runtime, and the kernel will use DC CVAC
	  operations if DC CVAP is not supported (following the behaviour of
	  DC CVAP itself if the system does not define a point of persistence).

config ARM64_RAS_EXTN
	bool "Enable support for RAS CPU Extensions"
	default y
	help
	  CPUs that support the Reliability, Availability and Serviceability
	  (RAS) Extensions, part of ARMv8.2 are able to track faults and
	  errors, classify them and report them to software.

	  On CPUs with these extensions system software can use additional
	  barriers to determine if faults are pending and read the
	  classification from a new set of registers.

	  Selecting this feature will allow the kernel to use these barriers
	  and access the new registers if the system supports the extension.
	  Platform RAS features may additionally depend on firmware support.

config ARM64_CNP
	bool "Enable support for Common Not Private (CNP) translations"
	default y
	depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
	help
	  Common Not Private (CNP) allows translation table entries to
	  be shared between different PEs in the same inner shareable
	  domain, so the hardware can use this fact to optimise the
	  caching of such entries in the TLB.

	  Selecting this option allows the CNP feature to be detected
	  at runtime, and does not affect PEs that do not implement
	  this feature.

endmenu

menu "ARMv8.3 architectural features"

config ARM64_PTR_AUTH
	bool "Enable support for pointer authentication"
	default y
	depends on !KVM || ARM64_VHE
	help
	  Pointer authentication (part of the ARMv8.3 Extensions) provides
	  instructions for signing and authenticating pointers against secret
	  keys, which can be used to mitigate Return Oriented Programming (ROP)
	  and other attacks.

	  This option enables these instructions at EL0 (i.e. for userspace).

	  Choosing this option will cause the kernel to initialise secret keys
	  for each process at exec() time, with these keys being
	  context-switched along with the process.

	  The feature is detected at runtime. If the feature is not present in
	  hardware it will not be advertised to userspace/KVM guest nor will it
	  be enabled. However, KVM guest also require VHE mode and hence
	  CONFIG_ARM64_VHE=y option to use this feature.

endmenu

config ARM64_SVE
	bool "ARM Scalable Vector Extension support"
	default y
	depends on !KVM || ARM64_VHE
	help
	  The Scalable Vector Extension (SVE) is an extension to the AArch64
	  execution state which complements and extends the SIMD functionality
	  of the base architecture to support much larger vectors and to enable
	  additional vectorisation opportunities.

	  To enable use of this extension on CPUs that implement it, say Y.

	  On CPUs that support the SVE2 extensions, this option will enable
	  those too.

	  Note that for architectural reasons, firmware _must_ implement SVE
	  support when running on SVE capable hardware.  The required support
	  is present in:

	    * version 1.5 and later of the ARM Trusted Firmware
	    * the AArch64 boot wrapper since commit 5e1261e08abf
	      ("bootwrapper: SVE: Enable SVE for EL2 and below").

	  For other firmware implementations, consult the firmware documentation
	  or vendor.

	  If you need the kernel to boot on SVE-capable hardware with broken
	  firmware, you may need to say N here until you get your firmware
	  fixed.  Otherwise, you may experience firmware panics or lockups when
	  booting the kernel.  If unsure and you are not observing these
	  symptoms, you should assume that it is safe to say Y.

	  CPUs that support SVE are architecturally required to support the
	  Virtualization Host Extensions (VHE), so the kernel makes no
	  provision for supporting SVE alongside KVM without VHE enabled.
	  Thus, you will need to enable CONFIG_ARM64_VHE if you want to support
	  KVM in the same kernel image.

config ARM64_MODULE_PLTS
	bool "Use PLTs to allow module memory to spill over into vmalloc area"
	select HAVE_MOD_ARCH_SPECIFIC
	help
	  Allocate PLTs when loading modules so that jumps and calls whose
	  targets are too far away for their relative offsets to be encoded
	  in the instructions themselves can be bounced via veneers in the
	  module's PLT. This allows modules to be allocated in the generic
	  vmalloc area after the dedicated module memory area has been
	  exhausted.

	  When running with address space randomization (KASLR), the module
	  region itself may be too far away for ordinary relative jumps and
	  calls, and so in that case, module PLTs are required and cannot be
	  disabled.

	  Specific errata workaround(s) might also force module PLTs to be
	  enabled (ARM64_ERRATUM_843419).

config ARM64_PSEUDO_NMI
	bool "Support for NMI-like interrupts"
	select CONFIG_ARM_GIC_V3
	help
	  Adds support for mimicking Non-Maskable Interrupts through the use of
	  GIC interrupt priority. This support requires version 3 or later of
	  ARM GIC.

	  This high priority configuration for interrupts needs to be
	  explicitly enabled by setting the kernel parameter
	  "irqchip.gicv3_pseudo_nmi" to 1.

	  If unsure, say N

if ARM64_PSEUDO_NMI
config ARM64_DEBUG_PRIORITY_MASKING
	bool "Debug interrupt priority masking"
	help
	  This adds runtime checks to functions enabling/disabling
	  interrupts when using priority masking. The additional checks verify
	  the validity of ICC_PMR_EL1 when calling concerned functions.

	  If unsure, say N
endif

config RELOCATABLE
	bool
	help
	  This builds the kernel as a Position Independent Executable (PIE),
	  which retains all relocation metadata required to relocate the
	  kernel binary at runtime to a different virtual address than the
	  address it was linked at.
	  Since AArch64 uses the RELA relocation format, this requires a
	  relocation pass at runtime even if the kernel is loaded at the
	  same address it was linked at.

config RANDOMIZE_BASE
	bool "Randomize the address of the kernel image"
	select ARM64_MODULE_PLTS if MODULES
	select RELOCATABLE
	help
	  Randomizes the virtual address at which the kernel image is
	  loaded, as a security feature that deters exploit attempts
	  relying on knowledge of the location of kernel internals.

	  It is the bootloader's job to provide entropy, by passing a
	  random u64 value in /chosen/kaslr-seed at kernel entry.

	  When booting via the UEFI stub, it will invoke the firmware's
	  EFI_RNG_PROTOCOL implementation (if available) to supply entropy
	  to the kernel proper. In addition, it will randomise the physical
	  location of the kernel Image as well.

	  If unsure, say N.

config RANDOMIZE_MODULE_REGION_FULL
	bool "Randomize the module region over a 4 GB range"
	depends on RANDOMIZE_BASE
	default y
	help
	  Randomizes the location of the module region inside a 4 GB window
	  covering the core kernel. This way, it is less likely for modules
	  to leak information about the location of core kernel data structures
	  but it does imply that function calls between modules and the core
	  kernel will need to be resolved via veneers in the module PLT.

	  When this option is not set, the module region will be randomized over
	  a limited range that contains the [_stext, _etext] interval of the
	  core kernel, so branch relocations are always in range.

config CC_HAVE_STACKPROTECTOR_SYSREG
	def_bool $(cc-option,-mstack-protector-guard=sysreg -mstack-protector-guard-reg=sp_el0 -mstack-protector-guard-offset=0)

config STACKPROTECTOR_PER_TASK
	def_bool y
	depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_SYSREG

endmenu

menu "Boot options"

config ARM64_ACPI_PARKING_PROTOCOL
	bool "Enable support for the ARM64 ACPI parking protocol"
	depends on ACPI
	help
	  Enable support for the ARM64 ACPI parking protocol. If disabled
	  the kernel will not allow booting through the ARM64 ACPI parking
	  protocol even if the corresponding data is present in the ACPI
	  MADT table.

config CMDLINE
	string "Default kernel command string"
	default ""
	help
	  Provide a set of default command-line options at build time by
	  entering them here. As a minimum, you should specify the the
	  root device (e.g. root=/dev/nfs).

config CMDLINE_FORCE
	bool "Always use the default kernel command string"
	help
	  Always use the default kernel command string, even if the boot
	  loader passes other arguments to the kernel.
	  This is useful if you cannot or don't want to change the
	  command-line options your boot loader passes to the kernel.

config EFI_STUB
	bool

config EFI
	bool "UEFI runtime support"
	depends on OF && !CPU_BIG_ENDIAN
	depends on KERNEL_MODE_NEON
	select ARCH_SUPPORTS_ACPI
	select LIBFDT
	select UCS2_STRING
	select EFI_PARAMS_FROM_FDT
	select EFI_RUNTIME_WRAPPERS
	select EFI_STUB
	select EFI_ARMSTUB
	default y
	help
	  This option provides support for runtime services provided
	  by UEFI firmware (such as non-volatile variables, realtime
          clock, and platform reset). A UEFI stub is also provided to
	  allow the kernel to be booted as an EFI application. This
	  is only useful on systems that have UEFI firmware.

config DMI
	bool "Enable support for SMBIOS (DMI) tables"
	depends on EFI
	default y
	help
	  This enables SMBIOS/DMI feature for systems.

	  This option is only useful on systems that have UEFI firmware.
	  However, even with this option, the resultant kernel should
	  continue to boot on existing non-UEFI platforms.

endmenu

config SYSVIPC_COMPAT
	def_bool y
	depends on COMPAT && SYSVIPC

config ARCH_ENABLE_HUGEPAGE_MIGRATION
	def_bool y
	depends on HUGETLB_PAGE && MIGRATION

menu "Power management options"

source "kernel/power/Kconfig"

config ARCH_HIBERNATION_POSSIBLE
	def_bool y
	depends on CPU_PM

config ARCH_HIBERNATION_HEADER
	def_bool y
	depends on HIBERNATION

config ARCH_SUSPEND_POSSIBLE
	def_bool y

endmenu

menu "CPU Power Management"

source "drivers/cpuidle/Kconfig"

source "drivers/cpufreq/Kconfig"

endmenu

source "drivers/firmware/Kconfig"

source "drivers/acpi/Kconfig"

source "arch/arm64/kvm/Kconfig"

if CRYPTO
source "arch/arm64/crypto/Kconfig"
endif