Introduce cpu_dcache_is_aliasing() across all architectures

[linux.git] / arch / arm / Kconfig

# SPDX-License-Identifier: GPL-2.0
config ARM
        bool
        default y
        select ARCH_32BIT_OFF_T
        select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE if HAVE_KRETPROBES && FRAME_POINTER && !ARM_UNWIND
        select ARCH_HAS_BINFMT_FLAT
        select ARCH_HAS_CPU_CACHE_ALIASING
        select ARCH_HAS_CPU_FINALIZE_INIT if MMU
        select ARCH_HAS_CURRENT_STACK_POINTER
        select ARCH_HAS_DEBUG_VIRTUAL if MMU
        select ARCH_HAS_DMA_ALLOC if MMU
        select ARCH_HAS_DMA_WRITE_COMBINE if !ARM_DMA_MEM_BUFFERABLE
        select ARCH_HAS_ELF_RANDOMIZE
        select ARCH_HAS_FORTIFY_SOURCE
        select ARCH_HAS_KEEPINITRD
        select ARCH_HAS_KCOV
        select ARCH_HAS_MEMBARRIER_SYNC_CORE
        select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
        select ARCH_HAS_PTE_SPECIAL if ARM_LPAE
        select ARCH_HAS_SETUP_DMA_OPS
        select ARCH_HAS_SET_MEMORY
        select ARCH_STACKWALK
        select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL
        select ARCH_HAS_STRICT_MODULE_RWX if MMU
        select ARCH_HAS_SYNC_DMA_FOR_DEVICE
        select ARCH_HAS_SYNC_DMA_FOR_CPU
        select ARCH_HAS_TEARDOWN_DMA_OPS if MMU
        select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
        select ARCH_HAVE_NMI_SAFE_CMPXCHG if CPU_V7 || CPU_V7M || CPU_V6K
        select ARCH_HAS_GCOV_PROFILE_ALL
        select ARCH_KEEP_MEMBLOCK
        select ARCH_HAS_UBSAN_SANITIZE_ALL
        select ARCH_MIGHT_HAVE_PC_PARPORT
        select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
        select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7
        select ARCH_SUPPORTS_ATOMIC_RMW
        select ARCH_SUPPORTS_HUGETLBFS if ARM_LPAE
        select ARCH_SUPPORTS_PER_VMA_LOCK
        select ARCH_USE_BUILTIN_BSWAP
        select ARCH_USE_CMPXCHG_LOCKREF
        select ARCH_USE_MEMTEST
        select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
        select ARCH_WANT_GENERAL_HUGETLB
        select ARCH_WANT_IPC_PARSE_VERSION
        select ARCH_WANT_LD_ORPHAN_WARN
        select BINFMT_FLAT_ARGVP_ENVP_ON_STACK
        select BUILDTIME_TABLE_SORT if MMU
        select COMMON_CLK if !(ARCH_RPC || ARCH_FOOTBRIDGE)
        select CLONE_BACKWARDS
        select CPU_PM if SUSPEND || CPU_IDLE
        select DCACHE_WORD_ACCESS if HAVE_EFFICIENT_UNALIGNED_ACCESS
        select DMA_DECLARE_COHERENT
        select DMA_GLOBAL_POOL if !MMU
        select DMA_OPS
        select DMA_NONCOHERENT_MMAP if MMU
        select EDAC_SUPPORT
        select EDAC_ATOMIC_SCRUB
        select GENERIC_ALLOCATOR
        select GENERIC_ARCH_TOPOLOGY if ARM_CPU_TOPOLOGY
        select GENERIC_ATOMIC64 if CPU_V7M || CPU_V6 || !CPU_32v6K || !AEABI
        select GENERIC_CLOCKEVENTS_BROADCAST if SMP
        select GENERIC_IRQ_IPI if SMP
        select GENERIC_CPU_AUTOPROBE
        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_LIB_DEVMEM_IS_ALLOWED
        select GENERIC_PCI_IOMAP
        select GENERIC_SCHED_CLOCK
        select GENERIC_SMP_IDLE_THREAD
        select HARDIRQS_SW_RESEND
        select HAS_IOPORT
        select HAVE_ARCH_AUDITSYSCALL if AEABI && !OABI_COMPAT
        select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6
        select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU
        select HAVE_ARCH_KFENCE if MMU && !XIP_KERNEL
        select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU
        select HAVE_ARCH_KASAN if MMU && !XIP_KERNEL
        select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN
        select HAVE_ARCH_MMAP_RND_BITS if MMU
        select HAVE_ARCH_PFN_VALID
        select HAVE_ARCH_SECCOMP
        select HAVE_ARCH_SECCOMP_FILTER if AEABI && !OABI_COMPAT
        select HAVE_ARCH_THREAD_STRUCT_WHITELIST
        select HAVE_ARCH_TRACEHOOK
        select HAVE_ARCH_TRANSPARENT_HUGEPAGE if ARM_LPAE
        select HAVE_ARM_SMCCC if CPU_V7
        select HAVE_EBPF_JIT if !CPU_ENDIAN_BE32
        select HAVE_CONTEXT_TRACKING_USER
        select HAVE_C_RECORDMCOUNT
        select HAVE_BUILDTIME_MCOUNT_SORT
        select HAVE_DEBUG_KMEMLEAK if !XIP_KERNEL
        select HAVE_DMA_CONTIGUOUS if MMU
        select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU
        select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
        select HAVE_EFFICIENT_UNALIGNED_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && MMU
        select HAVE_EXIT_THREAD
        select HAVE_FAST_GUP if ARM_LPAE
        select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
        select HAVE_FUNCTION_ERROR_INJECTION
        select HAVE_FUNCTION_GRAPH_TRACER
        select HAVE_FUNCTION_TRACER if !XIP_KERNEL
        select HAVE_GCC_PLUGINS
        select HAVE_HW_BREAKPOINT if PERF_EVENTS && (CPU_V6 || CPU_V6K || CPU_V7)
        select HAVE_IRQ_TIME_ACCOUNTING
        select HAVE_KERNEL_GZIP
        select HAVE_KERNEL_LZ4
        select HAVE_KERNEL_LZMA
        select HAVE_KERNEL_LZO
        select HAVE_KERNEL_XZ
        select HAVE_KPROBES if !XIP_KERNEL && !CPU_ENDIAN_BE32 && !CPU_V7M
        select HAVE_KRETPROBES if HAVE_KPROBES
        select HAVE_MOD_ARCH_SPECIFIC
        select HAVE_NMI
        select HAVE_OPTPROBES if !THUMB2_KERNEL
        select HAVE_PCI if MMU
        select HAVE_PERF_EVENTS
        select HAVE_PERF_REGS
        select HAVE_PERF_USER_STACK_DUMP
        select MMU_GATHER_RCU_TABLE_FREE if SMP && ARM_LPAE
        select HAVE_REGS_AND_STACK_ACCESS_API
        select HAVE_RSEQ
        select HAVE_STACKPROTECTOR
        select HAVE_SYSCALL_TRACEPOINTS
        select HAVE_UID16
        select HAVE_VIRT_CPU_ACCOUNTING_GEN
        select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU
        select IRQ_FORCED_THREADING
        select LOCK_MM_AND_FIND_VMA
        select MODULES_USE_ELF_REL
        select NEED_DMA_MAP_STATE
        select OF_EARLY_FLATTREE if OF
        select OLD_SIGACTION
        select OLD_SIGSUSPEND3
        select PCI_DOMAINS_GENERIC if PCI
        select PCI_SYSCALL if PCI
        select PERF_USE_VMALLOC
        select RTC_LIB
        select SPARSE_IRQ if !(ARCH_FOOTBRIDGE || ARCH_RPC)
        select SYS_SUPPORTS_APM_EMULATION
        select THREAD_INFO_IN_TASK
        select TIMER_OF if OF
        select HAVE_ARCH_VMAP_STACK if MMU && ARM_HAS_GROUP_RELOCS
        select TRACE_IRQFLAGS_SUPPORT if !CPU_V7M
        select USE_OF if !(ARCH_FOOTBRIDGE || ARCH_RPC || ARCH_SA1100)
        # Above selects are sorted alphabetically; please add new ones
        # according to that.  Thanks.
        help
          The ARM series is a line of low-power-consumption RISC chip designs
          licensed by ARM Ltd and targeted at embedded applications and
          handhelds such as the Compaq IPAQ.  ARM-based PCs are no longer
          manufactured, but legacy ARM-based PC hardware remains popular in
          Europe.  There is an ARM Linux project with a web page at
          <http://www.arm.linux.org.uk/>.

config ARM_HAS_GROUP_RELOCS
        def_bool y
        depends on !LD_IS_LLD || LLD_VERSION >= 140000
        depends on !COMPILE_TEST
        help
          Whether or not to use R_ARM_ALU_PC_Gn or R_ARM_LDR_PC_Gn group
          relocations, which have been around for a long time, but were not
          supported in LLD until version 14. The combined range is -/+ 256 MiB,
          which is usually sufficient, but not for allyesconfig, so we disable
          this feature when doing compile testing.

config ARM_DMA_USE_IOMMU
        bool
        select NEED_SG_DMA_LENGTH

if ARM_DMA_USE_IOMMU

config ARM_DMA_IOMMU_ALIGNMENT
        int "Maximum PAGE_SIZE order of alignment for DMA IOMMU buffers"
        range 4 9
        default 8
        help
          DMA mapping framework by default aligns all buffers to the smallest
          PAGE_SIZE order which is greater than or equal to the requested buffer
          size. This works well for buffers up to a few hundreds kilobytes, but
          for larger buffers it just a waste of address space. Drivers which has
          relatively small addressing window (like 64Mib) might run out of
          virtual space with just a few allocations.

          With this parameter you can specify the maximum PAGE_SIZE order for
          DMA IOMMU buffers. Larger buffers will be aligned only to this
          specified order. The order is expressed as a power of two multiplied
          by the PAGE_SIZE.

endif

config SYS_SUPPORTS_APM_EMULATION
        bool

config HAVE_TCM
        bool
        select GENERIC_ALLOCATOR

config HAVE_PROC_CPU
        bool

config NO_IOPORT_MAP
        bool

config SBUS
        bool

config STACKTRACE_SUPPORT
        bool
        default y

config LOCKDEP_SUPPORT
        bool
        default y

config ARCH_HAS_ILOG2_U32
        bool

config ARCH_HAS_ILOG2_U64
        bool

config ARCH_HAS_BANDGAP
        bool

config FIX_EARLYCON_MEM
        def_bool y if MMU

config GENERIC_HWEIGHT
        bool
        default y

config GENERIC_CALIBRATE_DELAY
        bool
        default y

config ARCH_MAY_HAVE_PC_FDC
        bool

config ARCH_SUPPORTS_UPROBES
        def_bool y

config GENERIC_ISA_DMA
        bool

config FIQ
        bool

config ARCH_MTD_XIP
        bool

config ARM_PATCH_PHYS_VIRT
        bool "Patch physical to virtual translations at runtime" if !ARCH_MULTIPLATFORM
        default y
        depends on MMU
        help
          Patch phys-to-virt and virt-to-phys translation functions at
          boot and module load time according to the position of the
          kernel in system memory.

          This can only be used with non-XIP MMU kernels where the base
          of physical memory is at a 2 MiB boundary.

          Only disable this option if you know that you do not require
          this feature (eg, building a kernel for a single machine) and
          you need to shrink the kernel to the minimal size.

config NEED_MACH_IO_H
        bool
        help
          Select this when mach/io.h is required to provide special
          definitions for this platform.  The need for mach/io.h should
          be avoided when possible.

config NEED_MACH_MEMORY_H
        bool
        help
          Select this when mach/memory.h is required to provide special
          definitions for this platform.  The need for mach/memory.h should
          be avoided when possible.

config PHYS_OFFSET
        hex "Physical address of main memory" if MMU
        depends on !ARM_PATCH_PHYS_VIRT || !AUTO_ZRELADDR
        default DRAM_BASE if !MMU
        default 0x00000000 if ARCH_FOOTBRIDGE
        default 0x10000000 if ARCH_OMAP1 || ARCH_RPC
        default 0xa0000000 if ARCH_PXA
        default 0xc0000000 if ARCH_EP93XX || ARCH_SA1100
        default 0
        help
          Please provide the physical address corresponding to the
          location of main memory in your system.

config GENERIC_BUG
        def_bool y
        depends on BUG

config PGTABLE_LEVELS
        int
        default 3 if ARM_LPAE
        default 2

menu "System Type"

config MMU
        bool "MMU-based Paged Memory Management Support"
        default y
        help
          Select if you want MMU-based virtualised addressing space
          support by paged memory management. If unsure, say 'Y'.

config ARM_SINGLE_ARMV7M
        def_bool !MMU
        select ARM_NVIC
        select CPU_V7M
        select NO_IOPORT_MAP

config ARCH_MMAP_RND_BITS_MIN
        default 8

config ARCH_MMAP_RND_BITS_MAX
        default 14 if PAGE_OFFSET=0x40000000
        default 15 if PAGE_OFFSET=0x80000000
        default 16

config ARCH_MULTIPLATFORM
        bool "Require kernel to be portable to multiple machines" if EXPERT
        depends on MMU && !(ARCH_FOOTBRIDGE || ARCH_RPC || ARCH_SA1100)
        default y
        help
          In general, all Arm machines can be supported in a single
          kernel image, covering either Armv4/v5 or Armv6/v7.

          However, some configuration options require hardcoding machine
          specific physical addresses or enable errata workarounds that may
          break other machines.

          Selecting N here allows using those options, including
          DEBUG_UNCOMPRESS, XIP_KERNEL and ZBOOT_ROM. If unsure, say Y.

source "arch/arm/Kconfig.platforms"

#
# This is sorted alphabetically by mach-* pathname.  However, plat-*
# Kconfigs may be included either alphabetically (according to the
# plat- suffix) or along side the corresponding mach-* source.
#
source "arch/arm/mach-actions/Kconfig"

source "arch/arm/mach-alpine/Kconfig"

source "arch/arm/mach-artpec/Kconfig"

source "arch/arm/mach-aspeed/Kconfig"

source "arch/arm/mach-at91/Kconfig"

source "arch/arm/mach-axxia/Kconfig"

source "arch/arm/mach-bcm/Kconfig"

source "arch/arm/mach-berlin/Kconfig"

source "arch/arm/mach-clps711x/Kconfig"

source "arch/arm/mach-davinci/Kconfig"

source "arch/arm/mach-digicolor/Kconfig"

source "arch/arm/mach-dove/Kconfig"

source "arch/arm/mach-ep93xx/Kconfig"

source "arch/arm/mach-exynos/Kconfig"

source "arch/arm/mach-footbridge/Kconfig"

source "arch/arm/mach-gemini/Kconfig"

source "arch/arm/mach-highbank/Kconfig"

source "arch/arm/mach-hisi/Kconfig"

source "arch/arm/mach-hpe/Kconfig"

source "arch/arm/mach-imx/Kconfig"

source "arch/arm/mach-ixp4xx/Kconfig"

source "arch/arm/mach-keystone/Kconfig"

source "arch/arm/mach-lpc32xx/Kconfig"

source "arch/arm/mach-mediatek/Kconfig"

source "arch/arm/mach-meson/Kconfig"

source "arch/arm/mach-milbeaut/Kconfig"

source "arch/arm/mach-mmp/Kconfig"

source "arch/arm/mach-mstar/Kconfig"

source "arch/arm/mach-mv78xx0/Kconfig"

source "arch/arm/mach-mvebu/Kconfig"

source "arch/arm/mach-mxs/Kconfig"

source "arch/arm/mach-nomadik/Kconfig"

source "arch/arm/mach-npcm/Kconfig"

source "arch/arm/mach-omap1/Kconfig"

source "arch/arm/mach-omap2/Kconfig"

source "arch/arm/mach-orion5x/Kconfig"

source "arch/arm/mach-pxa/Kconfig"

source "arch/arm/mach-qcom/Kconfig"

source "arch/arm/mach-realtek/Kconfig"

source "arch/arm/mach-rpc/Kconfig"

source "arch/arm/mach-rockchip/Kconfig"

source "arch/arm/mach-s3c/Kconfig"

source "arch/arm/mach-s5pv210/Kconfig"

source "arch/arm/mach-sa1100/Kconfig"

source "arch/arm/mach-shmobile/Kconfig"

source "arch/arm/mach-socfpga/Kconfig"

source "arch/arm/mach-spear/Kconfig"

source "arch/arm/mach-sti/Kconfig"

source "arch/arm/mach-stm32/Kconfig"

source "arch/arm/mach-sunxi/Kconfig"

source "arch/arm/mach-tegra/Kconfig"

source "arch/arm/mach-ux500/Kconfig"

source "arch/arm/mach-versatile/Kconfig"

source "arch/arm/mach-vt8500/Kconfig"

source "arch/arm/mach-zynq/Kconfig"

# ARMv7-M architecture
config ARCH_LPC18XX
        bool "NXP LPC18xx/LPC43xx"
        depends on ARM_SINGLE_ARMV7M
        select ARCH_HAS_RESET_CONTROLLER
        select ARM_AMBA
        select CLKSRC_LPC32XX
        select PINCTRL
        help
          Support for NXP's LPC18xx Cortex-M3 and LPC43xx Cortex-M4
          high performance microcontrollers.

config ARCH_MPS2
        bool "ARM MPS2 platform"
        depends on ARM_SINGLE_ARMV7M
        select ARM_AMBA
        select CLKSRC_MPS2
        help
          Support for Cortex-M Prototyping System (or V2M-MPS2) which comes
          with a range of available cores like Cortex-M3/M4/M7.

          Please, note that depends which Application Note is used memory map
          for the platform may vary, so adjustment of RAM base might be needed.

# Definitions to make life easier
config ARCH_ACORN
        bool

config PLAT_ORION
        bool
        select CLKSRC_MMIO
        select GENERIC_IRQ_CHIP
        select IRQ_DOMAIN

config PLAT_ORION_LEGACY
        bool
        select PLAT_ORION

config PLAT_VERSATILE
        bool

source "arch/arm/mm/Kconfig"

config IWMMXT
        bool "Enable iWMMXt support"
        depends on CPU_XSCALE || CPU_XSC3 || CPU_MOHAWK || CPU_PJ4 || CPU_PJ4B
        default y if PXA27x || PXA3xx || ARCH_MMP || CPU_PJ4 || CPU_PJ4B
        help
          Enable support for iWMMXt context switching at run time if
          running on a CPU that supports it.

if !MMU
source "arch/arm/Kconfig-nommu"
endif

config PJ4B_ERRATA_4742
        bool "PJ4B Errata 4742: IDLE Wake Up Commands can Cause the CPU Core to Cease Operation"
        depends on CPU_PJ4B && MACH_ARMADA_370
        default y
        help
          When coming out of either a Wait for Interrupt (WFI) or a Wait for
          Event (WFE) IDLE states, a specific timing sensitivity exists between
          the retiring WFI/WFE instructions and the newly issued subsequent
          instructions.  This sensitivity can result in a CPU hang scenario.
          Workaround:
          The software must insert either a Data Synchronization Barrier (DSB)
          or Data Memory Barrier (DMB) command immediately after the WFI/WFE
          instruction

config ARM_ERRATA_326103
        bool "ARM errata: FSR write bit incorrect on a SWP to read-only memory"
        depends on CPU_V6
        help
          Executing a SWP instruction to read-only memory does not set bit 11
          of the FSR on the ARM 1136 prior to r1p0. This causes the kernel to
          treat the access as a read, preventing a COW from occurring and
          causing the faulting task to livelock.

config ARM_ERRATA_411920
        bool "ARM errata: Invalidation of the Instruction Cache operation can fail"
        depends on CPU_V6 || CPU_V6K
        help
          Invalidation of the Instruction Cache operation can
          fail. This erratum is present in 1136 (before r1p4), 1156 and 1176.
          It does not affect the MPCore. This option enables the ARM Ltd.
          recommended workaround.

config ARM_ERRATA_430973
        bool "ARM errata: Stale prediction on replaced interworking branch"
        depends on CPU_V7
        help
          This option enables the workaround for the 430973 Cortex-A8
          r1p* erratum. If a code sequence containing an ARM/Thumb
          interworking branch is replaced with another code sequence at the
          same virtual address, whether due to self-modifying code or virtual
          to physical address re-mapping, Cortex-A8 does not recover from the
          stale interworking branch prediction. This results in Cortex-A8
          executing the new code sequence in the incorrect ARM or Thumb state.
          The workaround enables the BTB/BTAC operations by setting ACTLR.IBE
          and also flushes the branch target cache at every context switch.
          Note that setting specific bits in the ACTLR register may not be
          available in non-secure mode.

config ARM_ERRATA_458693
        bool "ARM errata: Processor deadlock when a false hazard is created"
        depends on CPU_V7
        depends on !ARCH_MULTIPLATFORM
        help
          This option enables the workaround for the 458693 Cortex-A8 (r2p0)
          erratum. For very specific sequences of memory operations, it is
          possible for a hazard condition intended for a cache line to instead
          be incorrectly associated with a different cache line. This false
          hazard might then cause a processor deadlock. The workaround enables
          the L1 caching of the NEON accesses and disables the PLD instruction
          in the ACTLR register. Note that setting specific bits in the ACTLR
          register may not be available in non-secure mode and thus is not
          available on a multiplatform kernel. This should be applied by the
          bootloader instead.

config ARM_ERRATA_460075
        bool "ARM errata: Data written to the L2 cache can be overwritten with stale data"
        depends on CPU_V7
        depends on !ARCH_MULTIPLATFORM
        help
          This option enables the workaround for the 460075 Cortex-A8 (r2p0)
          erratum. Any asynchronous access to the L2 cache may encounter a
          situation in which recent store transactions to the L2 cache are lost
          and overwritten with stale memory contents from external memory. The
          workaround disables the write-allocate mode for the L2 cache via the
          ACTLR register. Note that setting specific bits in the ACTLR register
          may not be available in non-secure mode and thus is not available on
          a multiplatform kernel. This should be applied by the bootloader
          instead.

config ARM_ERRATA_742230
        bool "ARM errata: DMB operation may be faulty"
        depends on CPU_V7 && SMP
        depends on !ARCH_MULTIPLATFORM
        help
          This option enables the workaround for the 742230 Cortex-A9
          (r1p0..r2p2) erratum. Under rare circumstances, a DMB instruction
          between two write operations may not ensure the correct visibility
          ordering of the two writes. This workaround sets a specific bit in
          the diagnostic register of the Cortex-A9 which causes the DMB
          instruction to behave as a DSB, ensuring the correct behaviour of
          the two writes. Note that setting specific bits in the diagnostics
          register may not be available in non-secure mode and thus is not
          available on a multiplatform kernel. This should be applied by the
          bootloader instead.

config ARM_ERRATA_742231
        bool "ARM errata: Incorrect hazard handling in the SCU may lead to data corruption"
        depends on CPU_V7 && SMP
        depends on !ARCH_MULTIPLATFORM
        help
          This option enables the workaround for the 742231 Cortex-A9
          (r2p0..r2p2) erratum. Under certain conditions, specific to the
          Cortex-A9 MPCore micro-architecture, two CPUs working in SMP mode,
          accessing some data located in the same cache line, may get corrupted
          data due to bad handling of the address hazard when the line gets
          replaced from one of the CPUs at the same time as another CPU is
          accessing it. This workaround sets specific bits in the diagnostic
          register of the Cortex-A9 which reduces the linefill issuing
          capabilities of the processor. Note that setting specific bits in the
          diagnostics register may not be available in non-secure mode and thus
          is not available on a multiplatform kernel. This should be applied by
          the bootloader instead.

config ARM_ERRATA_643719
        bool "ARM errata: LoUIS bit field in CLIDR register is incorrect"
        depends on CPU_V7 && SMP
        default y
        help
          This option enables the workaround for the 643719 Cortex-A9 (prior to
          r1p0) erratum. On affected cores the LoUIS bit field of the CLIDR
          register returns zero when it should return one. The workaround
          corrects this value, ensuring cache maintenance operations which use
          it behave as intended and avoiding data corruption.

config ARM_ERRATA_720789
        bool "ARM errata: TLBIASIDIS and TLBIMVAIS operations can broadcast a faulty ASID"
        depends on CPU_V7
        help
          This option enables the workaround for the 720789 Cortex-A9 (prior to
          r2p0) erratum. A faulty ASID can be sent to the other CPUs for the
          broadcasted CP15 TLB maintenance operations TLBIASIDIS and TLBIMVAIS.
          As a consequence of this erratum, some TLB entries which should be
          invalidated are not, resulting in an incoherency in the system page
          tables. The workaround changes the TLB flushing routines to invalidate
          entries regardless of the ASID.

config ARM_ERRATA_743622
        bool "ARM errata: Faulty hazard checking in the Store Buffer may lead to data corruption"
        depends on CPU_V7
        depends on !ARCH_MULTIPLATFORM
        help
          This option enables the workaround for the 743622 Cortex-A9
          (r2p*) erratum. Under very rare conditions, a faulty
          optimisation in the Cortex-A9 Store Buffer may lead to data
          corruption. This workaround sets a specific bit in the diagnostic
          register of the Cortex-A9 which disables the Store Buffer
          optimisation, preventing the defect from occurring. This has no
          visible impact on the overall performance or power consumption of the
          processor. Note that setting specific bits in the diagnostics register
          may not be available in non-secure mode and thus is not available on a
          multiplatform kernel. This should be applied by the bootloader instead.

config ARM_ERRATA_751472
        bool "ARM errata: Interrupted ICIALLUIS may prevent completion of broadcasted operation"
        depends on CPU_V7
        depends on !ARCH_MULTIPLATFORM
        help
          This option enables the workaround for the 751472 Cortex-A9 (prior
          to r3p0) erratum. An interrupted ICIALLUIS operation may prevent the
          completion of a following broadcasted operation if the second
          operation is received by a CPU before the ICIALLUIS has completed,
          potentially leading to corrupted entries in the cache or TLB.
          Note that setting specific bits in the diagnostics register may
          not be available in non-secure mode and thus is not available on
          a multiplatform kernel. This should be applied by the bootloader
          instead.

config ARM_ERRATA_754322
        bool "ARM errata: possible faulty MMU translations following an ASID switch"
        depends on CPU_V7
        help
          This option enables the workaround for the 754322 Cortex-A9 (r2p*,
          r3p*) erratum. A speculative memory access may cause a page table walk
          which starts prior to an ASID switch but completes afterwards. This
          can populate the micro-TLB with a stale entry which may be hit with
          the new ASID. This workaround places two dsb instructions in the mm
          switching code so that no page table walks can cross the ASID switch.

config ARM_ERRATA_754327
        bool "ARM errata: no automatic Store Buffer drain"
        depends on CPU_V7 && SMP
        help
          This option enables the workaround for the 754327 Cortex-A9 (prior to
          r2p0) erratum. The Store Buffer does not have any automatic draining
          mechanism and therefore a livelock may occur if an external agent
          continuously polls a memory location waiting to observe an update.
          This workaround defines cpu_relax() as smp_mb(), preventing correctly
          written polling loops from denying visibility of updates to memory.

config ARM_ERRATA_364296
        bool "ARM errata: Possible cache data corruption with hit-under-miss enabled"
        depends on CPU_V6
        help
          This options enables the workaround for the 364296 ARM1136
          r0p2 erratum (possible cache data corruption with
          hit-under-miss enabled). It sets the undocumented bit 31 in
          the auxiliary control register and the FI bit in the control
          register, thus disabling hit-under-miss without putting the
          processor into full low interrupt latency mode. ARM11MPCore
          is not affected.

config ARM_ERRATA_764369
        bool "ARM errata: Data cache line maintenance operation by MVA may not succeed"
        depends on CPU_V7 && SMP
        help
          This option enables the workaround for erratum 764369
          affecting Cortex-A9 MPCore with two or more processors (all
          current revisions). Under certain timing circumstances, a data
          cache line maintenance operation by MVA targeting an Inner
          Shareable memory region may fail to proceed up to either the
          Point of Coherency or to the Point of Unification of the
          system. This workaround adds a DSB instruction before the
          relevant cache maintenance functions and sets a specific bit
          in the diagnostic control register of the SCU.

config ARM_ERRATA_764319
        bool "ARM errata: Read to DBGPRSR and DBGOSLSR may generate Undefined instruction"
        depends on CPU_V7
        help
          This option enables the workaround for the 764319 Cortex A-9 erratum.
          CP14 read accesses to the DBGPRSR and DBGOSLSR registers generate an
          unexpected Undefined Instruction exception when the DBGSWENABLE
          external pin is set to 0, even when the CP14 accesses are performed
          from a privileged mode. This work around catches the exception in a
          way the kernel does not stop execution.

config ARM_ERRATA_775420
       bool "ARM errata: A data cache maintenance operation which aborts, might lead to deadlock"
       depends on CPU_V7
       help
         This option enables the workaround for the 775420 Cortex-A9 (r2p2,
         r2p6,r2p8,r2p10,r3p0) erratum. In case a data cache maintenance
         operation aborts with MMU exception, it might cause the processor
         to deadlock. This workaround puts DSB before executing ISB if
         an abort may occur on cache maintenance.

config ARM_ERRATA_798181
        bool "ARM errata: TLBI/DSB failure on Cortex-A15"
        depends on CPU_V7 && SMP
        help
          On Cortex-A15 (r0p0..r3p2) the TLBI*IS/DSB operations are not
          adequately shooting down all use of the old entries. This
          option enables the Linux kernel workaround for this erratum
          which sends an IPI to the CPUs that are running the same ASID
          as the one being invalidated.

config ARM_ERRATA_773022
        bool "ARM errata: incorrect instructions may be executed from loop buffer"
        depends on CPU_V7
        help
          This option enables the workaround for the 773022 Cortex-A15
          (up to r0p4) erratum. In certain rare sequences of code, the
          loop buffer may deliver incorrect instructions. This
          workaround disables the loop buffer to avoid the erratum.

config ARM_ERRATA_818325_852422
        bool "ARM errata: A12: some seqs of opposed cond code instrs => deadlock or corruption"
        depends on CPU_V7
        help
          This option enables the workaround for:
          - Cortex-A12 818325: Execution of an UNPREDICTABLE STR or STM
            instruction might deadlock.  Fixed in r0p1.
          - Cortex-A12 852422: Execution of a sequence of instructions might
            lead to either a data corruption or a CPU deadlock.  Not fixed in
            any Cortex-A12 cores yet.
          This workaround for all both errata involves setting bit[12] of the
          Feature Register. This bit disables an optimisation applied to a
          sequence of 2 instructions that use opposing condition codes.

config ARM_ERRATA_821420
        bool "ARM errata: A12: sequence of VMOV to core registers might lead to a dead lock"
        depends on CPU_V7
        help
          This option enables the workaround for the 821420 Cortex-A12
          (all revs) erratum. In very rare timing conditions, a sequence
          of VMOV to Core registers instructions, for which the second
          one is in the shadow of a branch or abort, can lead to a
          deadlock when the VMOV instructions are issued out-of-order.

config ARM_ERRATA_825619
        bool "ARM errata: A12: DMB NSHST/ISHST mixed ... might cause deadlock"
        depends on CPU_V7
        help
          This option enables the workaround for the 825619 Cortex-A12
          (all revs) erratum. Within rare timing constraints, executing a
          DMB NSHST or DMB ISHST instruction followed by a mix of Cacheable
          and Device/Strongly-Ordered loads and stores might cause deadlock

config ARM_ERRATA_857271
        bool "ARM errata: A12: CPU might deadlock under some very rare internal conditions"
        depends on CPU_V7
        help
          This option enables the workaround for the 857271 Cortex-A12
          (all revs) erratum. Under very rare timing conditions, the CPU might
          hang. The workaround is expected to have a < 1% performance impact.

config ARM_ERRATA_852421
        bool "ARM errata: A17: DMB ST might fail to create order between stores"
        depends on CPU_V7
        help
          This option enables the workaround for the 852421 Cortex-A17
          (r1p0, r1p1, r1p2) erratum. Under very rare timing conditions,
          execution of a DMB ST instruction might fail to properly order
          stores from GroupA and stores from GroupB.

config ARM_ERRATA_852423
        bool "ARM errata: A17: some seqs of opposed cond code instrs => deadlock or corruption"
        depends on CPU_V7
        help
          This option enables the workaround for:
          - Cortex-A17 852423: Execution of a sequence of instructions might
            lead to either a data corruption or a CPU deadlock.  Not fixed in
            any Cortex-A17 cores yet.
          This is identical to Cortex-A12 erratum 852422.  It is a separate
          config option from the A12 erratum due to the way errata are checked
          for and handled.

config ARM_ERRATA_857272
        bool "ARM errata: A17: CPU might deadlock under some very rare internal conditions"
        depends on CPU_V7
        help
          This option enables the workaround for the 857272 Cortex-A17 erratum.
          This erratum is not known to be fixed in any A17 revision.
          This is identical to Cortex-A12 erratum 857271.  It is a separate
          config option from the A12 erratum due to the way errata are checked
          for and handled.

endmenu

source "arch/arm/common/Kconfig"

menu "Bus support"

config ISA
        bool
        help
          Find out whether you have ISA slots on your motherboard.  ISA is the
          name of a bus system, i.e. the way the CPU talks to the other stuff
          inside your box.  Other bus systems are PCI, EISA, MicroChannel
          (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
          newer boards don't support it.  If you have ISA, say Y, otherwise N.

# Select ISA DMA interface
config ISA_DMA_API
        bool

config ARM_ERRATA_814220
        bool "ARM errata: Cache maintenance by set/way operations can execute out of order"
        depends on CPU_V7
        help
          The v7 ARM states that all cache and branch predictor maintenance
          operations that do not specify an address execute, relative to
          each other, in program order.
          However, because of this erratum, an L2 set/way cache maintenance
          operation can overtake an L1 set/way cache maintenance operation.
          This ERRATA only affected the Cortex-A7 and present in r0p2, r0p3,
          r0p4, r0p5.

endmenu

menu "Kernel Features"

config HAVE_SMP
        bool
        help
          This option should be selected by machines which have an SMP-
          capable CPU.

          The only effect of this option is to make the SMP-related
          options available to the user for configuration.

config SMP
        bool "Symmetric Multi-Processing"
        depends on CPU_V6K || CPU_V7
        depends on HAVE_SMP
        depends on MMU || ARM_MPU
        select IRQ_WORK
        help
          This enables support for systems with more than one CPU. If you have
          a system with only one CPU, say N. If you have a system with more
          than one CPU, say Y.

          If you say N here, the kernel will run on uni- and multiprocessor
          machines, but will use only one CPU of a multiprocessor machine. If
          you say Y here, the kernel will run on many, but not all,
          uniprocessor machines. On a uniprocessor machine, the kernel
          will run faster if you say N here.

          See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
          <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
          <http://tldp.org/HOWTO/SMP-HOWTO.html>.

          If you don't know what to do here, say N.

config SMP_ON_UP
        bool "Allow booting SMP kernel on uniprocessor systems"
        depends on SMP && MMU
        default y
        help
          SMP kernels contain instructions which fail on non-SMP processors.
          Enabling this option allows the kernel to modify itself to make
          these instructions safe.  Disabling it allows about 1K of space
          savings.

          If you don't know what to do here, say Y.


config CURRENT_POINTER_IN_TPIDRURO
        def_bool y
        depends on CPU_32v6K && !CPU_V6

config IRQSTACKS
        def_bool y
        select HAVE_IRQ_EXIT_ON_IRQ_STACK
        select HAVE_SOFTIRQ_ON_OWN_STACK

config ARM_CPU_TOPOLOGY
        bool "Support cpu topology definition"
        depends on SMP && CPU_V7
        default y
        help
          Support ARM cpu topology definition. The MPIDR register defines
          affinity between processors which is then used to describe the cpu
          topology of an ARM System.

config SCHED_MC
        bool "Multi-core scheduler support"
        depends on ARM_CPU_TOPOLOGY
        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"
        depends on ARM_CPU_TOPOLOGY
        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 HAVE_ARM_SCU
        bool
        help
          This option enables support for the ARM snoop control unit

config HAVE_ARM_ARCH_TIMER
        bool "Architected timer support"
        depends on CPU_V7
        select ARM_ARCH_TIMER
        help
          This option enables support for the ARM architected timer

config HAVE_ARM_TWD
        bool
        help
          This options enables support for the ARM timer and watchdog unit

config MCPM
        bool "Multi-Cluster Power Management"
        depends on CPU_V7 && SMP
        help
          This option provides the common power management infrastructure
          for (multi-)cluster based systems, such as big.LITTLE based
          systems.

config MCPM_QUAD_CLUSTER
        bool
        depends on MCPM
        help
          To avoid wasting resources unnecessarily, MCPM only supports up
          to 2 clusters by default.
          Platforms with 3 or 4 clusters that use MCPM must select this
          option to allow the additional clusters to be managed.

config BIG_LITTLE
        bool "big.LITTLE support (Experimental)"
        depends on CPU_V7 && SMP
        select MCPM
        help
          This option enables support selections for the big.LITTLE
          system architecture.

config BL_SWITCHER
        bool "big.LITTLE switcher support"
        depends on BIG_LITTLE && MCPM && HOTPLUG_CPU && ARM_GIC
        select CPU_PM
        help
          The big.LITTLE "switcher" provides the core functionality to
          transparently handle transition between a cluster of A15's
          and a cluster of A7's in a big.LITTLE system.

config BL_SWITCHER_DUMMY_IF
        tristate "Simple big.LITTLE switcher user interface"
        depends on BL_SWITCHER && DEBUG_KERNEL
        help
          This is a simple and dummy char dev interface to control
          the big.LITTLE switcher core code.  It is meant for
          debugging purposes only.

choice
        prompt "Memory split"
        depends on MMU
        default VMSPLIT_3G
        help
          Select the desired split between kernel and user memory.

          If you are not absolutely sure what you are doing, leave this
          option alone!

        config VMSPLIT_3G
                bool "3G/1G user/kernel split"
        config VMSPLIT_3G_OPT
                depends on !ARM_LPAE
                bool "3G/1G user/kernel split (for full 1G low memory)"
        config VMSPLIT_2G
                bool "2G/2G user/kernel split"
        config VMSPLIT_1G
                bool "1G/3G user/kernel split"
endchoice

config PAGE_OFFSET
        hex
        default PHYS_OFFSET if !MMU
        default 0x40000000 if VMSPLIT_1G
        default 0x80000000 if VMSPLIT_2G
        default 0xB0000000 if VMSPLIT_3G_OPT
        default 0xC0000000

config KASAN_SHADOW_OFFSET
        hex
        depends on KASAN
        default 0x1f000000 if PAGE_OFFSET=0x40000000
        default 0x5f000000 if PAGE_OFFSET=0x80000000
        default 0x9f000000 if PAGE_OFFSET=0xC0000000
        default 0x8f000000 if PAGE_OFFSET=0xB0000000
        default 0xffffffff

config NR_CPUS
        int "Maximum number of CPUs (2-32)"
        range 2 16 if DEBUG_KMAP_LOCAL
        range 2 32 if !DEBUG_KMAP_LOCAL
        depends on SMP
        default "4"
        help
          The maximum number of CPUs that the kernel can support.
          Up to 32 CPUs can be supported, or up to 16 if kmap_local()
          debugging is enabled, which uses half of the per-CPU fixmap
          slots as guard regions.

config HOTPLUG_CPU
        bool "Support for hot-pluggable CPUs"
        depends on SMP
        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.

config ARM_PSCI
        bool "Support for the ARM Power State Coordination Interface (PSCI)"
        depends on HAVE_ARM_SMCCC
        select ARM_PSCI_FW
        help
          Say Y here if you want Linux to communicate with system firmware
          implementing the PSCI specification for CPU-centric power
          management operations described in ARM document number ARM DEN
          0022A ("Power State Coordination Interface System Software on
          ARM processors").

config HZ_FIXED
        int
        default 128 if SOC_AT91RM9200
        default 0

choice
        depends on HZ_FIXED = 0
        prompt "Timer frequency"

config HZ_100
        bool "100 Hz"

config HZ_200
        bool "200 Hz"

config HZ_250
        bool "250 Hz"

config HZ_300
        bool "300 Hz"

config HZ_500
        bool "500 Hz"

config HZ_1000
        bool "1000 Hz"

endchoice

config HZ
        int
        default HZ_FIXED if HZ_FIXED != 0
        default 100 if HZ_100
        default 200 if HZ_200
        default 250 if HZ_250
        default 300 if HZ_300
        default 500 if HZ_500
        default 1000

config SCHED_HRTICK
        def_bool HIGH_RES_TIMERS

config THUMB2_KERNEL
        bool "Compile the kernel in Thumb-2 mode" if !CPU_THUMBONLY
        depends on (CPU_V7 || CPU_V7M) && !CPU_V6 && !CPU_V6K
        default y if CPU_THUMBONLY
        select ARM_UNWIND
        help
          By enabling this option, the kernel will be compiled in
          Thumb-2 mode.

          If unsure, say N.

config ARM_PATCH_IDIV
        bool "Runtime patch udiv/sdiv instructions into __aeabi_{u}idiv()"
        depends on CPU_32v7
        default y
        help
          The ARM compiler inserts calls to __aeabi_idiv() and
          __aeabi_uidiv() when it needs to perform division on signed
          and unsigned integers. Some v7 CPUs have support for the sdiv
          and udiv instructions that can be used to implement those
          functions.

          Enabling this option allows the kernel to modify itself to
          replace the first two instructions of these library functions
          with the sdiv or udiv plus "bx lr" instructions when the CPU
          it is running on supports them. Typically this will be faster
          and less power intensive than running the original library
          code to do integer division.

config AEABI
        bool "Use the ARM EABI to compile the kernel" if !CPU_V7 && \
                !CPU_V7M && !CPU_V6 && !CPU_V6K && !CC_IS_CLANG
        default CPU_V7 || CPU_V7M || CPU_V6 || CPU_V6K || CC_IS_CLANG
        help
          This option allows for the kernel to be compiled using the latest
          ARM ABI (aka EABI).  This is only useful if you are using a user
          space environment that is also compiled with EABI.

          Since there are major incompatibilities between the legacy ABI and
          EABI, especially with regard to structure member alignment, this
          option also changes the kernel syscall calling convention to
          disambiguate both ABIs and allow for backward compatibility support
          (selected with CONFIG_OABI_COMPAT).

          To use this you need GCC version 4.0.0 or later.

config OABI_COMPAT
        bool "Allow old ABI binaries to run with this kernel (EXPERIMENTAL)"
        depends on AEABI && !THUMB2_KERNEL
        help
          This option preserves the old syscall interface along with the
          new (ARM EABI) one. It also provides a compatibility layer to
          intercept syscalls that have structure arguments which layout
          in memory differs between the legacy ABI and the new ARM EABI
          (only for non "thumb" binaries). This option adds a tiny
          overhead to all syscalls and produces a slightly larger kernel.

          The seccomp filter system will not be available when this is
          selected, since there is no way yet to sensibly distinguish
          between calling conventions during filtering.

          If you know you'll be using only pure EABI user space then you
          can say N here. If this option is not selected and you attempt
          to execute a legacy ABI binary then the result will be
          UNPREDICTABLE (in fact it can be predicted that it won't work
          at all). If in doubt say N.

config ARCH_SELECT_MEMORY_MODEL
        def_bool y

config ARCH_FLATMEM_ENABLE
        def_bool !(ARCH_RPC || ARCH_SA1100)

config ARCH_SPARSEMEM_ENABLE
        def_bool !ARCH_FOOTBRIDGE
        select SPARSEMEM_STATIC if SPARSEMEM

config HIGHMEM
        bool "High Memory Support"
        depends on MMU
        select KMAP_LOCAL
        select KMAP_LOCAL_NON_LINEAR_PTE_ARRAY
        help
          The address space of ARM processors is only 4 Gigabytes large
          and it has to accommodate user address space, kernel address
          space as well as some memory mapped IO. That means that, if you
          have a large amount of physical memory and/or IO, not all of the
          memory can be "permanently mapped" by the kernel. The physical
          memory that is not permanently mapped is called "high memory".

          Depending on the selected kernel/user memory split, minimum
          vmalloc space and actual amount of RAM, you may not need this
          option which should result in a slightly faster kernel.

          If unsure, say n.

config HIGHPTE
        bool "Allocate 2nd-level pagetables from highmem" if EXPERT
        depends on HIGHMEM
        default y
        help
          The VM uses one page of physical memory for each page table.
          For systems with a lot of processes, this can use a lot of
          precious low memory, eventually leading to low memory being
          consumed by page tables.  Setting this option will allow
          user-space 2nd level page tables to reside in high memory.

config CPU_SW_DOMAIN_PAN
        bool "Enable use of CPU domains to implement privileged no-access"
        depends on MMU && !ARM_LPAE
        default y
        help
          Increase kernel security by ensuring that normal kernel accesses
          are unable to access userspace addresses.  This can help prevent
          use-after-free bugs becoming an exploitable privilege escalation
          by ensuring that magic values (such as LIST_POISON) will always
          fault when dereferenced.

          CPUs with low-vector mappings use a best-efforts implementation.
          Their lower 1MB needs to remain accessible for the vectors, but
          the remainder of userspace will become appropriately inaccessible.

config HW_PERF_EVENTS
        def_bool y
        depends on ARM_PMU

config ARM_MODULE_PLTS
        bool "Use PLTs to allow module memory to spill over into vmalloc area"
        depends on MODULES
        select KASAN_VMALLOC if KASAN
        default y
        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. The modules will use slightly more memory, but after
          rounding up to page size, the actual memory footprint is usually
          the same.

          Disabling this is usually safe for small single-platform
          configurations. If unsure, say y.

config ARCH_FORCE_MAX_ORDER
        int "Order of maximal physically contiguous allocations"
        default "11" if SOC_AM33XX
        default "8" if SA1111
        default "10"
        help
          The kernel page allocator limits the size of maximal physically
          contiguous allocations. The limit is called MAX_PAGE_ORDER and it
          defines the maximal power of two of number of pages that can be
          allocated as a single contiguous block. This option allows
          overriding the default setting when ability to allocate very
          large blocks of physically contiguous memory is required.

          Don't change if unsure.

config ALIGNMENT_TRAP
        def_bool CPU_CP15_MMU
        select HAVE_PROC_CPU if PROC_FS
        help
          ARM processors cannot fetch/store information which is not
          naturally aligned on the bus, i.e., a 4 byte fetch must start at an
          address divisible by 4. On 32-bit ARM processors, these non-aligned
          fetch/store instructions will be emulated in software if you say
          here, which has a severe performance impact. This is necessary for
          correct operation of some network protocols. With an IP-only
          configuration it is safe to say N, otherwise say Y.

config UACCESS_WITH_MEMCPY
        bool "Use kernel mem{cpy,set}() for {copy_to,clear}_user()"
        depends on MMU
        default y if CPU_FEROCEON
        help
          Implement faster copy_to_user and clear_user methods for CPU
          cores where a 8-word STM instruction give significantly higher
          memory write throughput than a sequence of individual 32bit stores.

          A possible side effect is a slight increase in scheduling latency
          between threads sharing the same address space if they invoke
          such copy operations with large buffers.

          However, if the CPU data cache is using a write-allocate mode,
          this option is unlikely to provide any performance gain.

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 XEN_DOM0
        def_bool y
        depends on XEN

config XEN
        bool "Xen guest support on ARM"
        depends on ARM && AEABI && OF
        depends on CPU_V7 && !CPU_V6
        depends on !GENERIC_ATOMIC64
        depends on MMU
        select ARCH_DMA_ADDR_T_64BIT
        select ARM_PSCI
        select SWIOTLB
        select SWIOTLB_XEN
        select PARAVIRT
        help
          Say Y if you want to run Linux in a Virtual Machine on Xen on ARM.

config CC_HAVE_STACKPROTECTOR_TLS
        def_bool $(cc-option,-mtp=cp15 -mstack-protector-guard=tls -mstack-protector-guard-offset=0)

config STACKPROTECTOR_PER_TASK
        bool "Use a unique stack canary value for each task"
        depends on STACKPROTECTOR && CURRENT_POINTER_IN_TPIDRURO && !XIP_DEFLATED_DATA
        depends on GCC_PLUGINS || CC_HAVE_STACKPROTECTOR_TLS
        select GCC_PLUGIN_ARM_SSP_PER_TASK if !CC_HAVE_STACKPROTECTOR_TLS
        default y
        help
          Due to the fact that GCC uses an ordinary symbol reference from
          which to load the value of the stack canary, this value can only
          change at reboot time on SMP systems, and all tasks running in the
          kernel's address space are forced to use the same canary value for
          the entire duration that the system is up.

          Enable this option to switch to a different method that uses a
          different canary value for each task.

endmenu

menu "Boot options"

config USE_OF
        bool "Flattened Device Tree support"
        select IRQ_DOMAIN
        select OF
        help
          Include support for flattened device tree machine descriptions.

config ARCH_WANT_FLAT_DTB_INSTALL
        def_bool y

config ATAGS
        bool "Support for the traditional ATAGS boot data passing"
        default y
        help
          This is the traditional way of passing data to the kernel at boot
          time. If you are solely relying on the flattened device tree (or
          the ARM_ATAG_DTB_COMPAT option) then you may unselect this option
          to remove ATAGS support from your kernel binary.

config DEPRECATED_PARAM_STRUCT
        bool "Provide old way to pass kernel parameters"
        depends on ATAGS
        help
          This was deprecated in 2001 and announced to live on for 5 years.
          Some old boot loaders still use this way.

# Compressed boot loader in ROM.  Yes, we really want to ask about
# TEXT and BSS so we preserve their values in the config files.
config ZBOOT_ROM_TEXT
        hex "Compressed ROM boot loader base address"
        default 0x0
        help
          The physical address at which the ROM-able zImage is to be
          placed in the target.  Platforms which normally make use of
          ROM-able zImage formats normally set this to a suitable
          value in their defconfig file.

          If ZBOOT_ROM is not enabled, this has no effect.

config ZBOOT_ROM_BSS
        hex "Compressed ROM boot loader BSS address"
        default 0x0
        help
          The base address of an area of read/write memory in the target
          for the ROM-able zImage which must be available while the
          decompressor is running. It must be large enough to hold the
          entire decompressed kernel plus an additional 128 KiB.
          Platforms which normally make use of ROM-able zImage formats
          normally set this to a suitable value in their defconfig file.

          If ZBOOT_ROM is not enabled, this has no effect.

config ZBOOT_ROM
        bool "Compressed boot loader in ROM/flash"
        depends on ZBOOT_ROM_TEXT != ZBOOT_ROM_BSS
        depends on !ARM_APPENDED_DTB && !XIP_KERNEL && !AUTO_ZRELADDR
        help
          Say Y here if you intend to execute your compressed kernel image
          (zImage) directly from ROM or flash.  If unsure, say N.

config ARM_APPENDED_DTB
        bool "Use appended device tree blob to zImage (EXPERIMENTAL)"
        depends on OF
        help
          With this option, the boot code will look for a device tree binary
          (DTB) appended to zImage
          (e.g. cat zImage <filename>.dtb > zImage_w_dtb).

          This is meant as a backward compatibility convenience for those
          systems with a bootloader that can't be upgraded to accommodate
          the documented boot protocol using a device tree.

          Beware that there is very little in terms of protection against
          this option being confused by leftover garbage in memory that might
          look like a DTB header after a reboot if no actual DTB is appended
          to zImage.  Do not leave this option active in a production kernel
          if you don't intend to always append a DTB.  Proper passing of the
          location into r2 of a bootloader provided DTB is always preferable
          to this option.

config ARM_ATAG_DTB_COMPAT
        bool "Supplement the appended DTB with traditional ATAG information"
        depends on ARM_APPENDED_DTB
        help
          Some old bootloaders can't be updated to a DTB capable one, yet
          they provide ATAGs with memory configuration, the ramdisk address,
          the kernel cmdline string, etc.  Such information is dynamically
          provided by the bootloader and can't always be stored in a static
          DTB.  To allow a device tree enabled kernel to be used with such
          bootloaders, this option allows zImage to extract the information
          from the ATAG list and store it at run time into the appended DTB.

choice
        prompt "Kernel command line type" if ARM_ATAG_DTB_COMPAT
        default ARM_ATAG_DTB_COMPAT_CMDLINE_FROM_BOOTLOADER

config ARM_ATAG_DTB_COMPAT_CMDLINE_FROM_BOOTLOADER
        bool "Use bootloader kernel arguments if available"
        help
          Uses the command-line options passed by the boot loader instead of
          the device tree bootargs property. If the boot loader doesn't provide
          any, the device tree bootargs property will be used.

config ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEND
        bool "Extend with bootloader kernel arguments"
        help
          The command-line arguments provided by the boot loader will be
          appended to the the device tree bootargs property.

endchoice

config CMDLINE
        string "Default kernel command string"
        default ""
        help
          On some architectures (e.g. CATS), there is currently no way
          for the boot loader to pass arguments to the kernel. For these
          architectures, you should supply some command-line options at build
          time by entering them here. As a minimum, you should specify the
          memory size and the root device (e.g., mem=64M root=/dev/nfs).

choice
        prompt "Kernel command line type" if CMDLINE != ""
        default CMDLINE_FROM_BOOTLOADER

config CMDLINE_FROM_BOOTLOADER
        bool "Use bootloader kernel arguments if available"
        help
          Uses the command-line options passed by the boot loader. If
          the boot loader doesn't provide any, the default kernel command
          string provided in CMDLINE will be used.

config CMDLINE_EXTEND
        bool "Extend bootloader kernel arguments"
        help
          The command-line arguments provided by the boot loader will be
          appended to the default kernel command string.

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.
endchoice

config XIP_KERNEL
        bool "Kernel Execute-In-Place from ROM"
        depends on !ARM_LPAE && !ARCH_MULTIPLATFORM
        depends on !ARM_PATCH_IDIV && !ARM_PATCH_PHYS_VIRT && !SMP_ON_UP
        help
          Execute-In-Place allows the kernel to run from non-volatile storage
          directly addressable by the CPU, such as NOR flash. This saves RAM
          space since the text section of the kernel is not loaded from flash
          to RAM.  Read-write sections, such as the data section and stack,
          are still copied to RAM.  The XIP kernel is not compressed since
          it has to run directly from flash, so it will take more space to
          store it.  The flash address used to link the kernel object files,
          and for storing it, is configuration dependent. Therefore, if you
          say Y here, you must know the proper physical address where to
          store the kernel image depending on your own flash memory usage.

          Also note that the make target becomes "make xipImage" rather than
          "make zImage" or "make Image".  The final kernel binary to put in
          ROM memory will be arch/arm/boot/xipImage.

          If unsure, say N.

config XIP_PHYS_ADDR
        hex "XIP Kernel Physical Location"
        depends on XIP_KERNEL
        default "0x00080000"
        help
          This is the physical address in your flash memory the kernel will
          be linked for and stored to.  This address is dependent on your
          own flash usage.

config XIP_DEFLATED_DATA
        bool "Store kernel .data section compressed in ROM"
        depends on XIP_KERNEL
        select ZLIB_INFLATE
        help
          Before the kernel is actually executed, its .data section has to be
          copied to RAM from ROM. This option allows for storing that data
          in compressed form and decompressed to RAM rather than merely being
          copied, saving some precious ROM space. A possible drawback is a
          slightly longer boot delay.

config ARCH_SUPPORTS_KEXEC
        def_bool (!SMP || PM_SLEEP_SMP) && MMU

config ATAGS_PROC
        bool "Export atags in procfs"
        depends on ATAGS && KEXEC
        default y
        help
          Should the atags used to boot the kernel be exported in an "atags"
          file in procfs. Useful with kexec.

config ARCH_SUPPORTS_CRASH_DUMP
        def_bool y

config AUTO_ZRELADDR
        bool "Auto calculation of the decompressed kernel image address" if !ARCH_MULTIPLATFORM
        default !(ARCH_FOOTBRIDGE || ARCH_RPC || ARCH_SA1100)
        help
          ZRELADDR is the physical address where the decompressed kernel
          image will be placed. If AUTO_ZRELADDR is selected, the address
          will be determined at run-time, either by masking the current IP
          with 0xf8000000, or, if invalid, from the DTB passed in r2.
          This assumes the zImage being placed in the first 128MB from
          start of memory.

config EFI_STUB
        bool

config EFI
        bool "UEFI runtime support"
        depends on OF && !CPU_BIG_ENDIAN && MMU && AUTO_ZRELADDR && !XIP_KERNEL
        select UCS2_STRING
        select EFI_PARAMS_FROM_FDT
        select EFI_STUB
        select EFI_GENERIC_STUB
        select EFI_RUNTIME_WRAPPERS
        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 for kernels that may run 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.

          NOTE: This does *NOT* enable or encourage the use of DMI quirks,
          i.e., the the practice of identifying the platform via DMI to
          decide whether certain workarounds for buggy hardware and/or
          firmware need to be enabled. This would require the DMI subsystem
          to be enabled much earlier than we do on ARM, which is non-trivial.

endmenu

menu "CPU Power Management"

source "drivers/cpufreq/Kconfig"

source "drivers/cpuidle/Kconfig"

endmenu

menu "Floating point emulation"

comment "At least one emulation must be selected"

config FPE_NWFPE
        bool "NWFPE math emulation"
        depends on (!AEABI || OABI_COMPAT) && !THUMB2_KERNEL
        help
          Say Y to include the NWFPE floating point emulator in the kernel.
          This is necessary to run most binaries. Linux does not currently
          support floating point hardware so you need to say Y here even if
          your machine has an FPA or floating point co-processor podule.

          You may say N here if you are going to load the Acorn FPEmulator
          early in the bootup.

config FPE_NWFPE_XP
        bool "Support extended precision"
        depends on FPE_NWFPE
        help
          Say Y to include 80-bit support in the kernel floating-point
          emulator.  Otherwise, only 32 and 64-bit support is compiled in.
          Note that gcc does not generate 80-bit operations by default,
          so in most cases this option only enlarges the size of the
          floating point emulator without any good reason.

          You almost surely want to say N here.

config FPE_FASTFPE
        bool "FastFPE math emulation (EXPERIMENTAL)"
        depends on (!AEABI || OABI_COMPAT) && !CPU_32v3
        help
          Say Y here to include the FAST floating point emulator in the kernel.
          This is an experimental much faster emulator which now also has full
          precision for the mantissa.  It does not support any exceptions.
          It is very simple, and approximately 3-6 times faster than NWFPE.

          It should be sufficient for most programs.  It may be not suitable
          for scientific calculations, but you have to check this for yourself.
          If you do not feel you need a faster FP emulation you should better
          choose NWFPE.

config VFP
        bool "VFP-format floating point maths"
        depends on CPU_V6 || CPU_V6K || CPU_ARM926T || CPU_V7 || CPU_FEROCEON
        help
          Say Y to include VFP support code in the kernel. This is needed
          if your hardware includes a VFP unit.

          Please see <file:Documentation/arch/arm/vfp/release-notes.rst> for
          release notes and additional status information.

          Say N if your target does not have VFP hardware.

config VFPv3
        bool
        depends on VFP
        default y if CPU_V7

config NEON
        bool "Advanced SIMD (NEON) Extension support"
        depends on VFPv3 && CPU_V7
        help
          Say Y to include support code for NEON, the ARMv7 Advanced SIMD
          Extension.

config KERNEL_MODE_NEON
        bool "Support for NEON in kernel mode"
        depends on NEON && AEABI
        help
          Say Y to include support for NEON in kernel mode.

endmenu

menu "Power management options"

source "kernel/power/Kconfig"

config ARCH_SUSPEND_POSSIBLE
        depends on CPU_ARM920T || CPU_ARM926T || CPU_FEROCEON || CPU_SA1100 || \
                CPU_V6 || CPU_V6K || CPU_V7 || CPU_V7M || CPU_XSC3 || CPU_XSCALE || CPU_MOHAWK
        def_bool y

config ARM_CPU_SUSPEND
        def_bool PM_SLEEP || BL_SWITCHER || ARM_PSCI_FW
        depends on ARCH_SUSPEND_POSSIBLE

config ARCH_HIBERNATION_POSSIBLE
        bool
        depends on MMU
        default y if ARCH_SUSPEND_POSSIBLE

endmenu

source "arch/arm/Kconfig.assembler"