treewide: replace '---help---' in Kconfig files with 'help'

[mirror_ubuntu-jammy-kernel.git] / arch / arm64 / Kconfig

# SPDX-License-Identifier: GPL-2.0-only
config ARM64
        def_bool y
        select ACPI_CCA_REQUIRED if ACPI
        select ACPI_GENERIC_GSI if ACPI
        select ACPI_GTDT if ACPI
        select ACPI_IORT if ACPI
        select ACPI_REDUCED_HARDWARE_ONLY if ACPI
        select ACPI_MCFG if (ACPI && PCI)
        select ACPI_SPCR_TABLE if ACPI
        select ACPI_PPTT if ACPI
        select ARCH_HAS_DEBUG_WX
        select ARCH_BINFMT_ELF_STATE
        select ARCH_HAS_DEBUG_VIRTUAL
        select ARCH_HAS_DEBUG_VM_PGTABLE
        select ARCH_HAS_DEVMEM_IS_ALLOWED
        select ARCH_HAS_DMA_PREP_COHERENT
        select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
        select ARCH_HAS_FAST_MULTIPLIER
        select ARCH_HAS_FORTIFY_SOURCE
        select ARCH_HAS_GCOV_PROFILE_ALL
        select ARCH_HAS_GIGANTIC_PAGE
        select ARCH_HAS_KCOV
        select ARCH_HAS_KEEPINITRD
        select ARCH_HAS_MEMBARRIER_SYNC_CORE
        select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
        select ARCH_HAS_PTE_DEVMAP
        select ARCH_HAS_PTE_SPECIAL
        select ARCH_HAS_SETUP_DMA_OPS
        select ARCH_HAS_SET_DIRECT_MAP
        select ARCH_HAS_SET_MEMORY
        select ARCH_HAS_STRICT_KERNEL_RWX
        select ARCH_HAS_STRICT_MODULE_RWX
        select ARCH_HAS_SYNC_DMA_FOR_DEVICE
        select ARCH_HAS_SYNC_DMA_FOR_CPU
        select ARCH_HAS_SYSCALL_WRAPPER
        select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT
        select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
        select ARCH_HAVE_ELF_PROT
        select ARCH_HAVE_NMI_SAFE_CMPXCHG
        select ARCH_INLINE_READ_LOCK if !PREEMPTION
        select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION
        select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPTION
        select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPTION
        select ARCH_INLINE_READ_UNLOCK if !PREEMPTION
        select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPTION
        select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPTION
        select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPTION
        select ARCH_INLINE_WRITE_LOCK if !PREEMPTION
        select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPTION
        select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPTION
        select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPTION
        select ARCH_INLINE_WRITE_UNLOCK if !PREEMPTION
        select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPTION
        select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPTION
        select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPTION
        select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPTION
        select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPTION
        select ARCH_INLINE_SPIN_LOCK if !PREEMPTION
        select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPTION
        select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPTION
        select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPTION
        select ARCH_INLINE_SPIN_UNLOCK if !PREEMPTION
        select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPTION
        select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPTION
        select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION
        select ARCH_KEEP_MEMBLOCK
        select ARCH_USE_CMPXCHG_LOCKREF
        select ARCH_USE_GNU_PROPERTY
        select ARCH_USE_QUEUED_RWLOCKS
        select ARCH_USE_QUEUED_SPINLOCKS
        select ARCH_USE_SYM_ANNOTATIONS
        select ARCH_SUPPORTS_MEMORY_FAILURE
        select ARCH_SUPPORTS_SHADOW_CALL_STACK if CC_HAVE_SHADOW_CALL_STACK
        select ARCH_SUPPORTS_ATOMIC_RMW
        select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && (GCC_VERSION >= 50000 || CC_IS_CLANG)
        select ARCH_SUPPORTS_NUMA_BALANCING
        select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
        select ARCH_WANT_DEFAULT_BPF_JIT
        select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
        select ARCH_WANT_FRAME_POINTERS
        select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
        select ARCH_HAS_UBSAN_SANITIZE_ALL
        select ARM_AMBA
        select ARM_ARCH_TIMER
        select ARM_GIC
        select AUDIT_ARCH_COMPAT_GENERIC
        select ARM_GIC_V2M if PCI
        select ARM_GIC_V3
        select ARM_GIC_V3_ITS if PCI
        select ARM_PSCI_FW
        select BUILDTIME_TABLE_SORT
        select CLONE_BACKWARDS
        select COMMON_CLK
        select CPU_PM if (SUSPEND || CPU_IDLE)
        select CRC32
        select DCACHE_WORD_ACCESS
        select DMA_DIRECT_REMAP
        select EDAC_SUPPORT
        select FRAME_POINTER
        select GENERIC_ALLOCATOR
        select GENERIC_ARCH_TOPOLOGY
        select GENERIC_CLOCKEVENTS
        select GENERIC_CLOCKEVENTS_BROADCAST
        select GENERIC_CPU_AUTOPROBE
        select GENERIC_CPU_VULNERABILITIES
        select GENERIC_EARLY_IOREMAP
        select GENERIC_IDLE_POLL_SETUP
        select GENERIC_IRQ_MULTI_HANDLER
        select GENERIC_IRQ_PROBE
        select GENERIC_IRQ_SHOW
        select GENERIC_IRQ_SHOW_LEVEL
        select GENERIC_PCI_IOMAP
        select GENERIC_PTDUMP
        select GENERIC_SCHED_CLOCK
        select GENERIC_SMP_IDLE_THREAD
        select GENERIC_STRNCPY_FROM_USER
        select GENERIC_STRNLEN_USER
        select GENERIC_TIME_VSYSCALL
        select GENERIC_GETTIMEOFDAY
        select HANDLE_DOMAIN_IRQ
        select HARDIRQS_SW_RESEND
        select HAVE_PCI
        select HAVE_ACPI_APEI if (ACPI && EFI)
        select HAVE_ALIGNED_STRUCT_PAGE if SLUB
        select HAVE_ARCH_AUDITSYSCALL
        select HAVE_ARCH_BITREVERSE
        select HAVE_ARCH_COMPILER_H
        select HAVE_ARCH_HUGE_VMAP
        select HAVE_ARCH_JUMP_LABEL
        select HAVE_ARCH_JUMP_LABEL_RELATIVE
        select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
        select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN
        select HAVE_ARCH_KGDB
        select HAVE_ARCH_MMAP_RND_BITS
        select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
        select HAVE_ARCH_PREL32_RELOCATIONS
        select HAVE_ARCH_SECCOMP_FILTER
        select HAVE_ARCH_STACKLEAK
        select HAVE_ARCH_THREAD_STRUCT_WHITELIST
        select HAVE_ARCH_TRACEHOOK
        select HAVE_ARCH_TRANSPARENT_HUGEPAGE
        select HAVE_ARCH_VMAP_STACK
        select HAVE_ARM_SMCCC
        select HAVE_ASM_MODVERSIONS
        select HAVE_EBPF_JIT
        select HAVE_C_RECORDMCOUNT
        select HAVE_CMPXCHG_DOUBLE
        select HAVE_CMPXCHG_LOCAL
        select HAVE_CONTEXT_TRACKING
        select HAVE_COPY_THREAD_TLS
        select HAVE_DEBUG_BUGVERBOSE
        select HAVE_DEBUG_KMEMLEAK
        select HAVE_DMA_CONTIGUOUS
        select HAVE_DYNAMIC_FTRACE
        select HAVE_DYNAMIC_FTRACE_WITH_REGS \
                if $(cc-option,-fpatchable-function-entry=2)
        select HAVE_EFFICIENT_UNALIGNED_ACCESS
        select HAVE_FAST_GUP
        select HAVE_FTRACE_MCOUNT_RECORD
        select HAVE_FUNCTION_TRACER
        select HAVE_FUNCTION_ERROR_INJECTION
        select HAVE_FUNCTION_GRAPH_TRACER
        select HAVE_GCC_PLUGINS
        select HAVE_HW_BREAKPOINT if PERF_EVENTS
        select HAVE_IRQ_TIME_ACCOUNTING
        select HAVE_NMI
        select HAVE_PATA_PLATFORM
        select HAVE_PERF_EVENTS
        select HAVE_PERF_REGS
        select HAVE_PERF_USER_STACK_DUMP
        select HAVE_REGS_AND_STACK_ACCESS_API
        select HAVE_FUNCTION_ARG_ACCESS_API
        select HAVE_FUTEX_CMPXCHG if FUTEX
        select MMU_GATHER_RCU_TABLE_FREE
        select HAVE_RSEQ
        select HAVE_STACKPROTECTOR
        select HAVE_SYSCALL_TRACEPOINTS
        select HAVE_KPROBES
        select HAVE_KRETPROBES
        select HAVE_GENERIC_VDSO
        select IOMMU_DMA if IOMMU_SUPPORT
        select IRQ_DOMAIN
        select IRQ_FORCED_THREADING
        select MODULES_USE_ELF_RELA
        select NEED_DMA_MAP_STATE
        select NEED_SG_DMA_LENGTH
        select OF
        select OF_EARLY_FLATTREE
        select PCI_DOMAINS_GENERIC if PCI
        select PCI_ECAM if (ACPI && PCI)
        select PCI_SYSCALL if PCI
        select POWER_RESET
        select POWER_SUPPLY
        select SPARSE_IRQ
        select SWIOTLB
        select SYSCTL_EXCEPTION_TRACE
        select THREAD_INFO_IN_TASK
        help
          ARM 64-bit (AArch64) Linux support.

config 64BIT
        def_bool y

config MMU
        def_bool y

config ARM64_PAGE_SHIFT
        int
        default 16 if ARM64_64K_PAGES
        default 14 if ARM64_16K_PAGES
        default 12

config ARM64_CONT_SHIFT
        int
        default 5 if ARM64_64K_PAGES
        default 7 if ARM64_16K_PAGES
        default 4

config ARCH_MMAP_RND_BITS_MIN
       default 14 if ARM64_64K_PAGES
       default 16 if ARM64_16K_PAGES
       default 18

# max bits determined by the following formula:
#  VA_BITS - PAGE_SHIFT - 3
config ARCH_MMAP_RND_BITS_MAX
       default 19 if ARM64_VA_BITS=36
       default 24 if ARM64_VA_BITS=39
       default 27 if ARM64_VA_BITS=42
       default 30 if ARM64_VA_BITS=47
       default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES
       default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES
       default 33 if ARM64_VA_BITS=48
       default 14 if ARM64_64K_PAGES
       default 16 if ARM64_16K_PAGES
       default 18

config ARCH_MMAP_RND_COMPAT_BITS_MIN
       default 7 if ARM64_64K_PAGES
       default 9 if ARM64_16K_PAGES
       default 11

config ARCH_MMAP_RND_COMPAT_BITS_MAX
       default 16

config NO_IOPORT_MAP
        def_bool y if !PCI

config STACKTRACE_SUPPORT
        def_bool y

config ILLEGAL_POINTER_VALUE
        hex
        default 0xdead000000000000

config LOCKDEP_SUPPORT
        def_bool y

config TRACE_IRQFLAGS_SUPPORT
        def_bool y

config GENERIC_BUG
        def_bool y
        depends on BUG

config GENERIC_BUG_RELATIVE_POINTERS
        def_bool y
        depends on GENERIC_BUG

config GENERIC_HWEIGHT
        def_bool y

config GENERIC_CSUM
        def_bool y

config GENERIC_CALIBRATE_DELAY
        def_bool y

config ZONE_DMA
        bool "Support DMA zone" if EXPERT
        default y

config ZONE_DMA32
        bool "Support DMA32 zone" if EXPERT
        default y

config ARCH_ENABLE_MEMORY_HOTPLUG
        def_bool y

config ARCH_ENABLE_MEMORY_HOTREMOVE
        def_bool y

config SMP
        def_bool y

config KERNEL_MODE_NEON
        def_bool y

config FIX_EARLYCON_MEM
        def_bool y

config PGTABLE_LEVELS
        int
        default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36
        default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42
        default 3 if ARM64_64K_PAGES && (ARM64_VA_BITS_48 || ARM64_VA_BITS_52)
        default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39
        default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47
        default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48

config ARCH_SUPPORTS_UPROBES
        def_bool y

config ARCH_PROC_KCORE_TEXT
        def_bool y

config BROKEN_GAS_INST
        def_bool !$(as-instr,1:\n.inst 0\n.rept . - 1b\n\nnop\n.endr\n)

config KASAN_SHADOW_OFFSET
        hex
        depends on KASAN
        default 0xdfffa00000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && !KASAN_SW_TAGS
        default 0xdfffd00000000000 if ARM64_VA_BITS_47 && !KASAN_SW_TAGS
        default 0xdffffe8000000000 if ARM64_VA_BITS_42 && !KASAN_SW_TAGS
        default 0xdfffffd000000000 if ARM64_VA_BITS_39 && !KASAN_SW_TAGS
        default 0xdffffffa00000000 if ARM64_VA_BITS_36 && !KASAN_SW_TAGS
        default 0xefff900000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && KASAN_SW_TAGS
        default 0xefffc80000000000 if ARM64_VA_BITS_47 && KASAN_SW_TAGS
        default 0xeffffe4000000000 if ARM64_VA_BITS_42 && KASAN_SW_TAGS
        default 0xefffffc800000000 if ARM64_VA_BITS_39 && KASAN_SW_TAGS
        default 0xeffffff900000000 if ARM64_VA_BITS_36 && KASAN_SW_TAGS
        default 0xffffffffffffffff

source "arch/arm64/Kconfig.platforms"

menu "Kernel Features"

menu "ARM errata workarounds via the alternatives framework"

config ARM64_WORKAROUND_CLEAN_CACHE
        bool

config ARM64_ERRATUM_826319
        bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted"
        default y
        select ARM64_WORKAROUND_CLEAN_CACHE
        help
          This option adds an alternative code sequence to work around ARM
          erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or
          AXI master interface and an L2 cache.

          If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors
          and is unable to accept a certain write via this interface, it will
          not progress on read data presented on the read data channel and the
          system can deadlock.

          The workaround promotes data cache clean instructions to
          data cache clean-and-invalidate.
          Please note that this does not necessarily enable the workaround,
          as it depends on the alternative framework, which will only patch
          the kernel if an affected CPU is detected.

          If unsure, say Y.

config ARM64_ERRATUM_827319
        bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect"
        default y
        select ARM64_WORKAROUND_CLEAN_CACHE
        help
          This option adds an alternative code sequence to work around ARM
          erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI
          master interface and an L2 cache.

          Under certain conditions this erratum can cause a clean line eviction
          to occur at the same time as another transaction to the same address
          on the AMBA 5 CHI interface, which can cause data corruption if the
          interconnect reorders the two transactions.

          The workaround promotes data cache clean instructions to
          data cache clean-and-invalidate.
          Please note that this does not necessarily enable the workaround,
          as it depends on the alternative framework, which will only patch
          the kernel if an affected CPU is detected.

          If unsure, say Y.

config ARM64_ERRATUM_824069
        bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop"
        default y
        select ARM64_WORKAROUND_CLEAN_CACHE
        help
          This option adds an alternative code sequence to work around ARM
          erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected
          to a coherent interconnect.

          If a Cortex-A53 processor is executing a store or prefetch for
          write instruction at the same time as a processor in another
          cluster is executing a cache maintenance operation to the same
          address, then this erratum might cause a clean cache line to be
          incorrectly marked as dirty.

          The workaround promotes data cache clean instructions to
          data cache clean-and-invalidate.
          Please note that this option does not necessarily enable the
          workaround, as it depends on the alternative framework, which will
          only patch the kernel if an affected CPU is detected.

          If unsure, say Y.

config ARM64_ERRATUM_819472
        bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption"
        default y
        select ARM64_WORKAROUND_CLEAN_CACHE
        help
          This option adds an alternative code sequence to work around ARM
          erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache
          present when it is connected to a coherent interconnect.

          If the processor is executing a load and store exclusive sequence at
          the same time as a processor in another cluster is executing a cache
          maintenance operation to the same address, then this erratum might
          cause data corruption.

          The workaround promotes data cache clean instructions to
          data cache clean-and-invalidate.
          Please note that this does not necessarily enable the workaround,
          as it depends on the alternative framework, which will only patch
          the kernel if an affected CPU is detected.

          If unsure, say Y.

config ARM64_ERRATUM_832075
        bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads"
        default y
        help
          This option adds an alternative code sequence to work around ARM
          erratum 832075 on Cortex-A57 parts up to r1p2.

          Affected Cortex-A57 parts might deadlock when exclusive load/store
          instructions to Write-Back memory are mixed with Device loads.

          The workaround is to promote device loads to use Load-Acquire
          semantics.
          Please note that this does not necessarily enable the workaround,
          as it depends on the alternative framework, which will only patch
          the kernel if an affected CPU is detected.

          If unsure, say Y.

config ARM64_ERRATUM_834220
        bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault"
        depends on KVM
        default y
        help
          This option adds an alternative code sequence to work around ARM
          erratum 834220 on Cortex-A57 parts up to r1p2.

          Affected Cortex-A57 parts might report a Stage 2 translation
          fault as the result of a Stage 1 fault for load crossing a
          page boundary when there is a permission or device memory
          alignment fault at Stage 1 and a translation fault at Stage 2.

          The workaround is to verify that the Stage 1 translation
          doesn't generate a fault before handling the Stage 2 fault.
          Please note that this does not necessarily enable the workaround,
          as it depends on the alternative framework, which will only patch
          the kernel if an affected CPU is detected.

          If unsure, say Y.

config ARM64_ERRATUM_845719
        bool "Cortex-A53: 845719: a load might read incorrect data"
        depends on COMPAT
        default y
        help
          This option adds an alternative code sequence to work around ARM
          erratum 845719 on Cortex-A53 parts up to r0p4.

          When running a compat (AArch32) userspace on an affected Cortex-A53
          part, a load at EL0 from a virtual address that matches the bottom 32
          bits of the virtual address used by a recent load at (AArch64) EL1
          might return incorrect data.

          The workaround is to write the contextidr_el1 register on exception
          return to a 32-bit task.
          Please note that this does not necessarily enable the workaround,
          as it depends on the alternative framework, which will only patch
          the kernel if an affected CPU is detected.

          If unsure, say Y.

config ARM64_ERRATUM_843419
        bool "Cortex-A53: 843419: A load or store might access an incorrect address"
        default y
        select ARM64_MODULE_PLTS if MODULES
        help
          This option links the kernel with '--fix-cortex-a53-843419' and
          enables PLT support to replace certain ADRP instructions, which can
          cause subsequent memory accesses to use an incorrect address on
          Cortex-A53 parts up to r0p4.

          If unsure, say Y.

config ARM64_ERRATUM_1024718
        bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update"
        default y
        help
          This option adds a workaround for ARM Cortex-A55 Erratum 1024718.

          Affected Cortex-A55 cores (r0p0, r0p1, r1p0) could cause incorrect
          update of the hardware dirty bit when the DBM/AP bits are updated
          without a break-before-make. The workaround is to disable the usage
          of hardware DBM locally on the affected cores. CPUs not affected by
          this erratum will continue to use the feature.

          If unsure, say Y.

config ARM64_ERRATUM_1418040
        bool "Cortex-A76/Neoverse-N1: MRC read following MRRC read of specific Generic Timer in AArch32 might give incorrect result"
        default y
        depends on COMPAT
        help
          This option adds a workaround for ARM Cortex-A76/Neoverse-N1
          errata 1188873 and 1418040.

          Affected Cortex-A76/Neoverse-N1 cores (r0p0 to r3p1) could
          cause register corruption when accessing the timer registers
          from AArch32 userspace.

          If unsure, say Y.

config ARM64_WORKAROUND_SPECULATIVE_AT
        bool

config ARM64_ERRATUM_1165522
        bool "Cortex-A76: 1165522: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
        default y
        select ARM64_WORKAROUND_SPECULATIVE_AT
        help
          This option adds a workaround for ARM Cortex-A76 erratum 1165522.

          Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could end-up with
          corrupted TLBs by speculating an AT instruction during a guest
          context switch.

          If unsure, say Y.

config ARM64_ERRATUM_1319367
        bool "Cortex-A57/A72: 1319537: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
        default y
        select ARM64_WORKAROUND_SPECULATIVE_AT
        help
          This option adds work arounds for ARM Cortex-A57 erratum 1319537
          and A72 erratum 1319367

          Cortex-A57 and A72 cores could end-up with corrupted TLBs by
          speculating an AT instruction during a guest context switch.

          If unsure, say Y.

config ARM64_ERRATUM_1530923
        bool "Cortex-A55: 1530923: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
        default y
        select ARM64_WORKAROUND_SPECULATIVE_AT
        help
          This option adds a workaround for ARM Cortex-A55 erratum 1530923.

          Affected Cortex-A55 cores (r0p0, r0p1, r1p0, r2p0) could end-up with
          corrupted TLBs by speculating an AT instruction during a guest
          context switch.

          If unsure, say Y.

config ARM64_WORKAROUND_REPEAT_TLBI
        bool

config ARM64_ERRATUM_1286807
        bool "Cortex-A76: Modification of the translation table for a virtual address might lead to read-after-read ordering violation"
        default y
        select ARM64_WORKAROUND_REPEAT_TLBI
        help
          This option adds a workaround for ARM Cortex-A76 erratum 1286807.

          On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual
          address for a cacheable mapping of a location is being
          accessed by a core while another core is remapping the virtual
          address to a new physical page using the recommended
          break-before-make sequence, then under very rare circumstances
          TLBI+DSB completes before a read using the translation being
          invalidated has been observed by other observers. The
          workaround repeats the TLBI+DSB operation.

config ARM64_ERRATUM_1463225
        bool "Cortex-A76: Software Step might prevent interrupt recognition"
        default y
        help
          This option adds a workaround for Arm Cortex-A76 erratum 1463225.

          On the affected Cortex-A76 cores (r0p0 to r3p1), software stepping
          of a system call instruction (SVC) can prevent recognition of
          subsequent interrupts when software stepping is disabled in the
          exception handler of the system call and either kernel debugging
          is enabled or VHE is in use.

          Work around the erratum by triggering a dummy step exception
          when handling a system call from a task that is being stepped
          in a VHE configuration of the kernel.

          If unsure, say Y.

config ARM64_ERRATUM_1542419
        bool "Neoverse-N1: workaround mis-ordering of instruction fetches"
        default y
        help
          This option adds a workaround for ARM Neoverse-N1 erratum
          1542419.

          Affected Neoverse-N1 cores could execute a stale instruction when
          modified by another CPU. The workaround depends on a firmware
          counterpart.

          Workaround the issue by hiding the DIC feature from EL0. This
          forces user-space to perform cache maintenance.

          If unsure, say Y.

config CAVIUM_ERRATUM_22375
        bool "Cavium erratum 22375, 24313"
        default y
        help
          Enable workaround for errata 22375 and 24313.

          This implements two gicv3-its errata workarounds for ThunderX. Both
          with a small impact affecting only ITS table allocation.

            erratum 22375: only alloc 8MB table size
            erratum 24313: ignore memory access type

          The fixes are in ITS initialization and basically ignore memory access
          type and table size provided by the TYPER and BASER registers.

          If unsure, say Y.

config CAVIUM_ERRATUM_23144
        bool "Cavium erratum 23144: ITS SYNC hang on dual socket system"
        depends on NUMA
        default y
        help
          ITS SYNC command hang for cross node io and collections/cpu mapping.

          If unsure, say Y.

config CAVIUM_ERRATUM_23154
        bool "Cavium erratum 23154: Access to ICC_IAR1_EL1 is not sync'ed"
        default y
        help
          The gicv3 of ThunderX requires a modified version for
          reading the IAR status to ensure data synchronization
          (access to icc_iar1_el1 is not sync'ed before and after).

          If unsure, say Y.

config CAVIUM_ERRATUM_27456
        bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption"
        default y
        help
          On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI
          instructions may cause the icache to become corrupted if it
          contains data for a non-current ASID.  The fix is to
          invalidate the icache when changing the mm context.

          If unsure, say Y.

config CAVIUM_ERRATUM_30115
        bool "Cavium erratum 30115: Guest may disable interrupts in host"
        default y
        help
          On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through
          1.2, and T83 Pass 1.0, KVM guest execution may disable
          interrupts in host. Trapping both GICv3 group-0 and group-1
          accesses sidesteps the issue.

          If unsure, say Y.

config CAVIUM_TX2_ERRATUM_219
        bool "Cavium ThunderX2 erratum 219: PRFM between TTBR change and ISB fails"
        default y
        help
          On Cavium ThunderX2, a load, store or prefetch instruction between a
          TTBR update and the corresponding context synchronizing operation can
          cause a spurious Data Abort to be delivered to any hardware thread in
          the CPU core.

          Work around the issue by avoiding the problematic code sequence and
          trapping KVM guest TTBRx_EL1 writes to EL2 when SMT is enabled. The
          trap handler performs the corresponding register access, skips the
          instruction and ensures context synchronization by virtue of the
          exception return.

          If unsure, say Y.

config FUJITSU_ERRATUM_010001
        bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly"
        default y
        help
          This option adds a workaround for Fujitsu-A64FX erratum E#010001.
          On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory
          accesses may cause undefined fault (Data abort, DFSC=0b111111).
          This fault occurs under a specific hardware condition when a
          load/store instruction performs an address translation using:
          case-1  TTBR0_EL1 with TCR_EL1.NFD0 == 1.
          case-2  TTBR0_EL2 with TCR_EL2.NFD0 == 1.
          case-3  TTBR1_EL1 with TCR_EL1.NFD1 == 1.
          case-4  TTBR1_EL2 with TCR_EL2.NFD1 == 1.

          The workaround is to ensure these bits are clear in TCR_ELx.
          The workaround only affects the Fujitsu-A64FX.

          If unsure, say Y.

config HISILICON_ERRATUM_161600802
        bool "Hip07 161600802: Erroneous redistributor VLPI base"
        default y
        help
          The HiSilicon Hip07 SoC uses the wrong redistributor base
          when issued ITS commands such as VMOVP and VMAPP, and requires
          a 128kB offset to be applied to the target address in this commands.

          If unsure, say Y.

config QCOM_FALKOR_ERRATUM_1003
        bool "Falkor E1003: Incorrect translation due to ASID change"
        default y
        help
          On Falkor v1, an incorrect ASID may be cached in the TLB when ASID
          and BADDR are changed together in TTBRx_EL1. Since we keep the ASID
          in TTBR1_EL1, this situation only occurs in the entry trampoline and
          then only for entries in the walk cache, since the leaf translation
          is unchanged. Work around the erratum by invalidating the walk cache
          entries for the trampoline before entering the kernel proper.

config QCOM_FALKOR_ERRATUM_1009
        bool "Falkor E1009: Prematurely complete a DSB after a TLBI"
        default y
        select ARM64_WORKAROUND_REPEAT_TLBI
        help
          On Falkor v1, the CPU may prematurely complete a DSB following a
          TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation
          one more time to fix the issue.

          If unsure, say Y.

config QCOM_QDF2400_ERRATUM_0065
        bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size"
        default y
        help
          On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports
          ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have
          been indicated as 16Bytes (0xf), not 8Bytes (0x7).

          If unsure, say Y.

config QCOM_FALKOR_ERRATUM_E1041
        bool "Falkor E1041: Speculative instruction fetches might cause errant memory access"
        default y
        help
          Falkor CPU may speculatively fetch instructions from an improper
          memory location when MMU translation is changed from SCTLR_ELn[M]=1
          to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem.

          If unsure, say Y.

config SOCIONEXT_SYNQUACER_PREITS
        bool "Socionext Synquacer: Workaround for GICv3 pre-ITS"
        default y
        help
          Socionext Synquacer SoCs implement a separate h/w block to generate
          MSI doorbell writes with non-zero values for the device ID.

          If unsure, say Y.

endmenu


choice
        prompt "Page size"
        default ARM64_4K_PAGES
        help
          Page size (translation granule) configuration.

config ARM64_4K_PAGES
        bool "4KB"
        help
          This feature enables 4KB pages support.

config ARM64_16K_PAGES
        bool "16KB"
        help
          The system will use 16KB pages support. AArch32 emulation
          requires applications compiled with 16K (or a multiple of 16K)
          aligned segments.

config ARM64_64K_PAGES
        bool "64KB"
        help
          This feature enables 64KB pages support (4KB by default)
          allowing only two levels of page tables and faster TLB
          look-up. AArch32 emulation requires applications compiled
          with 64K aligned segments.

endchoice

choice
        prompt "Virtual address space size"
        default ARM64_VA_BITS_39 if ARM64_4K_PAGES
        default ARM64_VA_BITS_47 if ARM64_16K_PAGES
        default ARM64_VA_BITS_42 if ARM64_64K_PAGES
        help
          Allows choosing one of multiple possible virtual address
          space sizes. The level of translation table is determined by
          a combination of page size and virtual address space size.

config ARM64_VA_BITS_36
        bool "36-bit" if EXPERT
        depends on ARM64_16K_PAGES

config ARM64_VA_BITS_39
        bool "39-bit"
        depends on ARM64_4K_PAGES

config ARM64_VA_BITS_42
        bool "42-bit"
        depends on ARM64_64K_PAGES

config ARM64_VA_BITS_47
        bool "47-bit"
        depends on ARM64_16K_PAGES

config ARM64_VA_BITS_48
        bool "48-bit"

config ARM64_VA_BITS_52
        bool "52-bit"
        depends on ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN)
        help
          Enable 52-bit virtual addressing for userspace when explicitly
          requested via a hint to mmap(). The kernel will also use 52-bit
          virtual addresses for its own mappings (provided HW support for
          this feature is available, otherwise it reverts to 48-bit).

          NOTE: Enabling 52-bit virtual addressing in conjunction with
          ARMv8.3 Pointer Authentication will result in the PAC being
          reduced from 7 bits to 3 bits, which may have a significant
          impact on its susceptibility to brute-force attacks.

          If unsure, select 48-bit virtual addressing instead.

endchoice

config ARM64_FORCE_52BIT
        bool "Force 52-bit virtual addresses for userspace"
        depends on ARM64_VA_BITS_52 && EXPERT
        help
          For systems with 52-bit userspace VAs enabled, the kernel will attempt
          to maintain compatibility with older software by providing 48-bit VAs
          unless a hint is supplied to mmap.

          This configuration option disables the 48-bit compatibility logic, and
          forces all userspace addresses to be 52-bit on HW that supports it. One
          should only enable this configuration option for stress testing userspace
          memory management code. If unsure say N here.

config ARM64_VA_BITS
        int
        default 36 if ARM64_VA_BITS_36
        default 39 if ARM64_VA_BITS_39
        default 42 if ARM64_VA_BITS_42
        default 47 if ARM64_VA_BITS_47
        default 48 if ARM64_VA_BITS_48
        default 52 if ARM64_VA_BITS_52

choice
        prompt "Physical address space size"
        default ARM64_PA_BITS_48
        help
          Choose the maximum physical address range that the kernel will
          support.

config ARM64_PA_BITS_48
        bool "48-bit"

config ARM64_PA_BITS_52
        bool "52-bit (ARMv8.2)"
        depends on ARM64_64K_PAGES
        depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
        help
          Enable support for a 52-bit physical address space, introduced as
          part of the ARMv8.2-LPA extension.

          With this enabled, the kernel will also continue to work on CPUs that
          do not support ARMv8.2-LPA, but with some added memory overhead (and
          minor performance overhead).

endchoice

config ARM64_PA_BITS
        int
        default 48 if ARM64_PA_BITS_48
        default 52 if ARM64_PA_BITS_52

choice
        prompt "Endianness"
        default CPU_LITTLE_ENDIAN
        help
          Select the endianness of data accesses performed by the CPU. Userspace
          applications will need to be compiled and linked for the endianness
          that is selected here.

config CPU_BIG_ENDIAN
       bool "Build big-endian kernel"
       help
          Say Y if you plan on running a kernel with a big-endian userspace.

config CPU_LITTLE_ENDIAN
        bool "Build little-endian kernel"
        help
          Say Y if you plan on running a kernel with a little-endian userspace.
          This is usually the case for distributions targeting arm64.

endchoice

config SCHED_MC
        bool "Multi-core scheduler support"
        help
          Multi-core scheduler support improves the CPU scheduler's decision
          making when dealing with multi-core CPU chips at a cost of slightly
          increased overhead in some places. If unsure say N here.

config SCHED_SMT
        bool "SMT scheduler support"
        help
          Improves the CPU scheduler's decision making when dealing with
          MultiThreading at a cost of slightly increased overhead in some
          places. If unsure say N here.

config NR_CPUS
        int "Maximum number of CPUs (2-4096)"
        range 2 4096
        default "256"

config HOTPLUG_CPU
        bool "Support for hot-pluggable CPUs"
        select GENERIC_IRQ_MIGRATION
        help
          Say Y here to experiment with turning CPUs off and on.  CPUs
          can be controlled through /sys/devices/system/cpu.

# Common NUMA Features
config NUMA
        bool "NUMA Memory Allocation and Scheduler Support"
        select ACPI_NUMA if ACPI
        select OF_NUMA
        help
          Enable NUMA (Non-Uniform Memory Access) support.

          The kernel will try to allocate memory used by a CPU on the
          local memory of the CPU and add some more
          NUMA awareness to the kernel.

config NODES_SHIFT
        int "Maximum NUMA Nodes (as a power of 2)"
        range 1 10
        default "2"
        depends on NEED_MULTIPLE_NODES
        help
          Specify the maximum number of NUMA Nodes available on the target
          system.  Increases memory reserved to accommodate various tables.

config USE_PERCPU_NUMA_NODE_ID
        def_bool y
        depends on NUMA

config HAVE_SETUP_PER_CPU_AREA
        def_bool y
        depends on NUMA

config NEED_PER_CPU_EMBED_FIRST_CHUNK
        def_bool y
        depends on NUMA

config HOLES_IN_ZONE
        def_bool y

source "kernel/Kconfig.hz"

config ARCH_SUPPORTS_DEBUG_PAGEALLOC
        def_bool y

config ARCH_SPARSEMEM_ENABLE
        def_bool y
        select SPARSEMEM_VMEMMAP_ENABLE

config ARCH_SPARSEMEM_DEFAULT
        def_bool ARCH_SPARSEMEM_ENABLE

config ARCH_SELECT_MEMORY_MODEL
        def_bool ARCH_SPARSEMEM_ENABLE

config ARCH_FLATMEM_ENABLE
        def_bool !NUMA

config HAVE_ARCH_PFN_VALID
        def_bool y

config HW_PERF_EVENTS
        def_bool y
        depends on ARM_PMU

config SYS_SUPPORTS_HUGETLBFS
        def_bool y

config ARCH_WANT_HUGE_PMD_SHARE

config ARCH_HAS_CACHE_LINE_SIZE
        def_bool y

config ARCH_ENABLE_SPLIT_PMD_PTLOCK
        def_bool y if PGTABLE_LEVELS > 2

# Supported by clang >= 7.0
config CC_HAVE_SHADOW_CALL_STACK
        def_bool $(cc-option, -fsanitize=shadow-call-stack -ffixed-x18)

config SECCOMP
        bool "Enable seccomp to safely compute untrusted bytecode"
        help
          This kernel feature is useful for number crunching applications
          that may need to compute untrusted bytecode during their
          execution. By using pipes or other transports made available to
          the process as file descriptors supporting the read/write
          syscalls, it's possible to isolate those applications in
          their own address space using seccomp. Once seccomp is
          enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
          and the task is only allowed to execute a few safe syscalls
          defined by each seccomp mode.

config PARAVIRT
        bool "Enable paravirtualization code"
        help
          This changes the kernel so it can modify itself when it is run
          under a hypervisor, potentially improving performance significantly
          over full virtualization.

config PARAVIRT_TIME_ACCOUNTING
        bool "Paravirtual steal time accounting"
        select PARAVIRT
        help
          Select this option to enable fine granularity task steal time
          accounting. Time spent executing other tasks in parallel with
          the current vCPU is discounted from the vCPU power. To account for
          that, there can be a small performance impact.

          If in doubt, say N here.

config KEXEC
        depends on PM_SLEEP_SMP
        select KEXEC_CORE
        bool "kexec system call"
        help
          kexec is a system call that implements the ability to shutdown your
          current kernel, and to start another kernel.  It is like a reboot
          but it is independent of the system firmware.   And like a reboot
          you can start any kernel with it, not just Linux.

config KEXEC_FILE
        bool "kexec file based system call"
        select KEXEC_CORE
        help
          This is new version of kexec system call. This system call is
          file based and takes file descriptors as system call argument
          for kernel and initramfs as opposed to list of segments as
          accepted by previous system call.

config KEXEC_SIG
        bool "Verify kernel signature during kexec_file_load() syscall"
        depends on KEXEC_FILE
        help
          Select this option to verify a signature with loaded kernel
          image. If configured, any attempt of loading a image without
          valid signature will fail.

          In addition to that option, you need to enable signature
          verification for the corresponding kernel image type being
          loaded in order for this to work.

config KEXEC_IMAGE_VERIFY_SIG
        bool "Enable Image signature verification support"
        default y
        depends on KEXEC_SIG
        depends on EFI && SIGNED_PE_FILE_VERIFICATION
        help
          Enable Image signature verification support.

comment "Support for PE file signature verification disabled"
        depends on KEXEC_SIG
        depends on !EFI || !SIGNED_PE_FILE_VERIFICATION

config CRASH_DUMP
        bool "Build kdump crash kernel"
        help
          Generate crash dump after being started by kexec. This should
          be normally only set in special crash dump kernels which are
          loaded in the main kernel with kexec-tools into a specially
          reserved region and then later executed after a crash by
          kdump/kexec.

          For more details see Documentation/admin-guide/kdump/kdump.rst

config XEN_DOM0
        def_bool y
        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.

config ARM64_TAGGED_ADDR_ABI
        bool "Enable the tagged user addresses syscall ABI"
        default y
        help
          When this option is enabled, user applications can opt in to a
          relaxed ABI via prctl() allowing tagged addresses to be passed
          to system calls as pointer arguments. For details, see
          Documentation/arm64/tagged-address-abi.rst.

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.rst 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.

config COMPAT_VDSO
        bool "Enable vDSO for 32-bit applications"
        depends on !CPU_BIG_ENDIAN && "$(CROSS_COMPILE_COMPAT)" != ""
        select GENERIC_COMPAT_VDSO
        default y
        help
          Place in the process address space of 32-bit applications an
          ELF shared object providing fast implementations of gettimeofday
          and clock_gettime.

          You must have a 32-bit build of glibc 2.22 or later for programs
          to seamlessly take advantage of this.

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
        default ARM64_USE_LSE_ATOMICS
        depends on $(as-instr,.arch_extension lse)

config ARM64_USE_LSE_ATOMICS
        bool "Atomic instructions"
        depends on JUMP_LABEL
        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
        depends on (CC_HAS_SIGN_RETURN_ADDRESS || CC_HAS_BRANCH_PROT_PAC_RET) && AS_HAS_PAC
        # GCC 9.1 and later inserts a .note.gnu.property section note for PAC
        # which is only understood by binutils starting with version 2.33.1.
        depends on !CC_IS_GCC || GCC_VERSION < 90100 || LD_VERSION >= 233010000
        depends on !CC_IS_CLANG || AS_HAS_CFI_NEGATE_RA_STATE
        depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS)
        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.

          If the compiler supports the -mbranch-protection or
          -msign-return-address flag (e.g. GCC 7 or later), then this option
          will also cause the kernel itself to be compiled with return address
          protection. In this case, and if the target hardware is known to
          support pointer authentication, then CONFIG_STACKPROTECTOR can be
          disabled with minimal loss of protection.

          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.

          If the feature is present on the boot CPU but not on a late CPU, then
          the late CPU will be parked. Also, if the boot CPU does not have
          address auth and the late CPU has then the late CPU will still boot
          but with the feature disabled. On such a system, this option should
          not be selected.

          This feature works with FUNCTION_GRAPH_TRACER option only if
          DYNAMIC_FTRACE_WITH_REGS is enabled.

config CC_HAS_BRANCH_PROT_PAC_RET
        # GCC 9 or later, clang 8 or later
        def_bool $(cc-option,-mbranch-protection=pac-ret+leaf)

config CC_HAS_SIGN_RETURN_ADDRESS
        # GCC 7, 8
        def_bool $(cc-option,-msign-return-address=all)

config AS_HAS_PAC
        def_bool $(as-option,-Wa$(comma)-march=armv8.3-a)

config AS_HAS_CFI_NEGATE_RA_STATE
        def_bool $(as-instr,.cfi_startproc\n.cfi_negate_ra_state\n.cfi_endproc\n)

endmenu

menu "ARMv8.4 architectural features"

config ARM64_AMU_EXTN
        bool "Enable support for the Activity Monitors Unit CPU extension"
        default y
        help
          The activity monitors extension is an optional extension introduced
          by the ARMv8.4 CPU architecture. This enables support for version 1
          of the activity monitors architecture, AMUv1.

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

          Note that for architectural reasons, firmware _must_ implement AMU
          support when running on CPUs that present the activity monitors
          extension. The required support is present in:
            * Version 1.5 and later of the ARM Trusted Firmware

          For kernels that have this configuration enabled but boot with broken
          firmware, you may need to say N here until the firmware is fixed.
          Otherwise you may experience firmware panics or lockups when
          accessing the counter registers. Even if you are not observing these
          symptoms, the values returned by the register reads might not
          correctly reflect reality. Most commonly, the value read will be 0,
          indicating that the counter is not enabled.

endmenu

menu "ARMv8.5 architectural features"

config ARM64_BTI
        bool "Branch Target Identification support"
        default y
        help
          Branch Target Identification (part of the ARMv8.5 Extensions)
          provides a mechanism to limit the set of locations to which computed
          branch instructions such as BR or BLR can jump.

          To make use of BTI on CPUs that support it, say Y.

          BTI is intended to provide complementary protection to other control
          flow integrity protection mechanisms, such as the Pointer
          authentication mechanism provided as part of the ARMv8.3 Extensions.
          For this reason, it does not make sense to enable this option without
          also enabling support for pointer authentication.  Thus, when
          enabling this option you should also select ARM64_PTR_AUTH=y.

          Userspace binaries must also be specifically compiled to make use of
          this mechanism.  If you say N here or the hardware does not support
          BTI, such binaries can still run, but you get no additional
          enforcement of branch destinations.

config ARM64_BTI_KERNEL
        bool "Use Branch Target Identification for kernel"
        default y
        depends on ARM64_BTI
        depends on ARM64_PTR_AUTH
        depends on CC_HAS_BRANCH_PROT_PAC_RET_BTI
        # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94697
        depends on !CC_IS_GCC || GCC_VERSION >= 100100
        depends on !(CC_IS_CLANG && GCOV_KERNEL)
        depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS)
        help
          Build the kernel with Branch Target Identification annotations
          and enable enforcement of this for kernel code. When this option
          is enabled and the system supports BTI all kernel code including
          modular code must have BTI enabled.

config CC_HAS_BRANCH_PROT_PAC_RET_BTI
        # GCC 9 or later, clang 8 or later
        def_bool $(cc-option,-mbranch-protection=pac-ret+leaf+bti)

config ARM64_E0PD
        bool "Enable support for E0PD"
        default y
        help
          E0PD (part of the ARMv8.5 extensions) allows us to ensure
          that EL0 accesses made via TTBR1 always fault in constant time,
          providing similar benefits to KASLR as those provided by KPTI, but
          with lower overhead and without disrupting legitimate access to
          kernel memory such as SPE.

          This option enables E0PD for TTBR1 where available.

config ARCH_RANDOM
        bool "Enable support for random number generation"
        default y
        help
          Random number generation (part of the ARMv8.5 Extensions)
          provides a high bandwidth, cryptographically secure
          hardware random number generator.

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"
        depends on MODULES
        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 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
        select ARCH_HAS_RELR
        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"
        depends on CMDLINE != ""
        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_GENERIC_STUB
        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